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Amambo GN, Fombad FF, Chounna Ndongmo PW, Abong RA, Njouendou AJ, Beng AA, Nji TM, Esum ME, Fru-Cho J, Manuel R, Kebede D, Enyong PI, Hoerauf A, Koudou B, Bockarie M, Wanji S. Impact of repeated mass ivermectin administration using a community directed approach on L. loa infection in Chrysops silacea of the rain forest and forest savanna of Cameroon. Parasite Epidemiol Control 2024; 25:e00343. [PMID: 38405181 PMCID: PMC10884510 DOI: 10.1016/j.parepi.2024.e00343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/22/2023] [Accepted: 02/06/2024] [Indexed: 02/27/2024] Open
Abstract
Background Loiasis is an endemic filarial infection in the rainforest zone of West and Central Africa. Repeated annual community-directed treatment with ivermectin (CDTI) delivered for several years to control onchocerciasis has been shown to reduce the prevalence and intensity of Loiasis in some Loa loa-Onchocerca volvulus co-endemic areas. However, the impact of these multiple rounds of CDTI on entomological indicators of loiasis transmission is not known, and was therefore assessed in this study in areas with contrasting histories of CDTI. Methods The study was conducted in the East, North-west and South-west 1 CDTI project sites of Cameroon. Two communities per CDTI project were selected for fly collection and dissection. Ivermectin treatment coverage was documented in these areas, and this was correlated to Chrysops infection and infective rates. A total of 7029 female Chrysops were collected from 6 communities of the 3 CDTI projects (East, North-west, and South-west 1) and from 2 communities in a non-CDTI district (East). Results Chrysops biting densities and parous rates were significantly reduced in the North-west and South-west sites post-CDTI, while in the East, biting densities were similar in non-CDTI and CDTI sites, with higher parous rates observed in the non-CDTI site. Infection and infective rates in the East non-CDTI site were 4.4% and 1.8% respectively, as compared to 3.3% and 1.3% in the CDTI site after 10 ivermectin rounds (there were no baseline data for the latter). In the North-west site, significant reductions in Chrysops infection and infective rates from 10.2% and 4.2% respectively, to 3.5% and 1.2 (after 9 rounds of ivermectin treatment), were recorded following CDTI. In the South-west, infection rate significantly increased from 1.74% to 2.8% and infective rate remained statistically unchanged after 14 rounds of CDTI (0.45% - 0.40%). Similar trends in Mean Head L3 were observed except in the East site where this indicator was similar in both CDTI and control sites. Only in the North-west site did monthly transmission potentials decrease significantly. Conclusion This study demonstrated that the impact of repeated annual treatment with ivermectin for the control of onchocerciasis using community directed delivery approach on the entomological indicators of loiasis varies with bioecological zones. Community directed treatment with ivermectin induced a significant reduction in the entomological indicators of loiasis in the North-West project site which lies in forest savanna area. A non-significant decrease was observed in the East project site and in contrast, a significant increase was observed in the South-West 1 project site which both lies in the rainforest zones.
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Affiliation(s)
- Glory N. Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- Centre for Neglected Tropical Diseases (Incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- German Center for Infection Research (DZIF), Partner site Bonn-Cologne, Bonn, Germany
| | - Fanny F. Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Patrick W. Chounna Ndongmo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Department of Biomedical Science, Faculty of Health Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Theobald Mue Nji
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- Department of Sociology and Anthropology, Faculty of Social and Management Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Jerome Fru-Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Ritter Manuel
- Institute of Medical Microbiology, Immunology, and Parasitology, University Hospital Bonn, Germany
| | - Deribe Kebede
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton BN1 9PX, United Kingdom
- School of Public Health, College of Health Sciences, Addis Ababa University, Ethiopia
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology, and Parasitology, University Hospital Bonn, Germany
- German Center for Infection Research (DZIF), Partner site Bonn-Cologne, Bonn, Germany
| | - Benjamin Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Moses Bockarie
- Centre for Neglected Tropical Diseases (Incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
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Ateutchia-Ngouanet S, Nanfack-Minkeu F, Mavridis K, Wanji S, Demanou M, Vontas J, Djouaka R. Monitoring Aedes populations for arboviruses, Wolbachia, insecticide resistance and its mechanisms in various agroecosystems in Benin. Acta Trop 2024; 253:107178. [PMID: 38461924 DOI: 10.1016/j.actatropica.2024.107178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/07/2024] [Accepted: 03/07/2024] [Indexed: 03/12/2024]
Abstract
Aedes mosquitoes are the main vectors of arboviruses in Benin. Cases of dengue have been reported in Benin with all four serotypes of the virus actively circulating in this region. Some agricultural settings are known to harbor Aedes vectors responsible for the transmission of arboviruses. The massive use of certain insecticides in agricultural settings has probably contributed to insecticide resistance in these vectors. In Benin, the susceptibility of arbovirus vectors to insecticides is poorly studied. In addition, the distribution of Wolbachia spp., which is used against some arboviruses is unknown. Moreover, there is limited information regarding the vectors responsible for the transmission of arboviruses in Benin. This present study monitored the species composition, arboviruses, and Wolbachia symbiont status, as well as the phenotypic and molecular insecticide resistance profile of Aedes populations from three agroecosystems in Benin. Aedes species identification was performed morphologically and confirmed using qPCR. (RT)-qPCR assay was applied for monitoring the presence of DENV, CHIKV, ZIKV, and WNV pathogens as well as for naturally occurring Wolbachia symbionts. Insecticide resistance was assessed phenotypically, by permethrin (0.75%) exposure of Adults (F0) using World Health Organization (WHO) bioassay protocols, and at the molecular level, using TaqMan (RT)-qPCR assays for assessing knock-down resistance (kdr) mutations (F1534C, V1016G/I, and S989P) and the expression levels of eight detoxification genes (P450s from the CYP9 and CYP6 families, carboxylesterases and glutathione-S-transferases). Aedes aegypti (Ae. aegypti) mosquitoes were the most abundant (93.9%) in the three agroecosystems studied, followed by Aedes albopictus (Ae. albopictus) mosquitoes (6.1%). No arboviruses were detected in the study's mosquito populations. Naturally occurring Wolbachia symbionts were present in 7 pools out of 15 pools tested. This could influence the effectiveness of vector control strategies based on exogenously introduced Wolbachia, all present in the three agroecosystems. Full susceptibility to permethrin was observed in all tested populations of Ae. albopictus. On the contrary, Ae. aegypti were found to be resistant in all three agroecosystem sites except for banana plantation sites, where full susceptibility was observed. Molecular analysis revealed that individual target site resistance kdr mutations F1534C and V1016G/I were detected in most Ae. aegypti populations. Additionally, double mutant (F1534C + V1016G/I) mosquitoes were found in some populations, and in one case, triple mutant (F1534C + V1016G/I + S989P) mosquitoes were detected. Metabolic resistance, as reflected by overexpression of three P450 genes (CYP6BB2, CYP9J26, and CYP9J32), was also detected in Ae. aegypti mosquitoes. Our study provides information that could be used to strategize future vector control strategies and highlights the importance of continuing vector surveillance. Future studies should assess the effect of piperonyl butoxide (PBO) on metabolic resistance and identify the different strains of Wolbachia spp., to choose the best vector control strategies in Benin.
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Affiliation(s)
- S Ateutchia-Ngouanet
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin; Department Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. BOX 63, Buea, Cameroon.
| | - F Nanfack-Minkeu
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin; Department of Biology, The College of Wooster, OH, USA
| | - K Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - S Wanji
- Department Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. BOX 63, Buea, Cameroon
| | - M Demanou
- Regional Yellow Fever Laboratory Coordinator World Health Organization, Inter-Country Support Team West Africa, 03 PO BOX 7019 Ouagadougou 03, Burkina Faso
| | - J Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece; Department of Crop Science, Pesticide Science Laboratory, Agricultural University of Athens, Athens 11855, Greece
| | - R Djouaka
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin
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Chunda VC, Fombad FF, Kien CA, Ebai R, Esofi F, Ntuh AN, Ouam E, Gandjui NVT, Ekanya R, Nietcho F, Nchang LC, Magha C, Njouendou AJ, Enyong P, Hoerauf A, Wanji S, Ritter M. Comparative development of human filariae Loa loa, Onchocerca volvulus and Mansonella perstans in immunocompromised mouse strains. Front Trop Dis 2024; 5:1293632. [PMID: 38655273 PMCID: PMC7615855 DOI: 10.3389/fitd.2024.1293632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Introduction Mouse models of human filarial infections are not only urgently needed to investigate the biology of the nematodes and their modulation of the host's immunity, but will also provide a platform to screen and test novel anti-filarial drugs. Recently, murine Loa loa infection models have been stablished using immunocompromised mouse strains, whereas murine Mansonella perstans infections have not been implemented until now. Methods Therefore, we aim to establish experimental M. perstans infections using the immunocompromised mouse strains RAG2IL-2Rγ-/- (lack B, T and natural killer cells), IL-4Rα/IL-5-/- (impaired IL-4/5 signalling and eosinophil activation) and NOD.Cg-PrkdcscidIl2rgtm1Wj l/SzJ (NOD scid gamma, NSG) BALB/c mice (lack mature lymphocytes) through subcutaneous (s.c.) or intraperitoneal (i.p.) inoculation of infective stage 3 larvae (L3) isolated from engorged vectors. Results In total, 145 immunocompromised mice have been inoculated with 3,250 M. perstans, 3,337 O. volvulus, and 2,720 Loa loa L3 to comparatively analyse which immunocompromised mouse strain is susceptible to human filarial infections. Whereas, no M. perstans and O. volvulus L3 could be recovered upon 2-63 days post-inoculation, a 62-66% Loa loa L3 recovery rate could be achieved in the different mouse strains. Gender of mice, type of inoculation (s.c. or i.p.) or time point of analysis (2-63 days post inoculation) did not interfere with the success of L3 recovery. In addition, administration of the immune suppressants hydrocortisone, prednisolone and cyclophosphamide did not restore M. perstans L3 recovery rates. Discussion These findings show that RAG2IL-2Rg-/-BALB/c and C57BL/6, IL-4Rα/IL-5-/- BALB/c and NSG mice were not susceptible to M. perstans and O. volvulus L3 inoculation using the applied methods, whereas Loa loa infection could be maintained. Further studies should investigate if humanized immunocompromised mice might be susceptible to M. perstans. and O. volvulus.
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Affiliation(s)
- Valerine C. Chunda
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Chi Anizette Kien
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Rene Ebai
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Frederick Esofi
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Anna Ning Ntuh
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Emmanuel Ouam
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Narcisse Victor Tchamatchoua Gandjui
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Relindis Ekanya
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Franck Nietcho
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Lucy Cho Nchang
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Chefor Magha
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Peter Enyong
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, Bonn, Germany
| | - Samuel Wanji
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
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Tanue EA, Omam LA, Ayuk GT, Noukeme BM, Metuge A, Nganmou I, Ebob MB, Donovan L, Stratil AS, Counihan H, Nkfusai CN, Hawkings H, Homolova B, Berryman E, Kolawole M, Zoungrana Y, Achu D, Wanji S, Omam EN. A formative cross-sectional study to assess caregiver's health-seeking behaviour and knowledge surrounding malaria, and understand the burden of malaria among children under-five in conflict-affected communities of Cameroon. Malar J 2024; 23:99. [PMID: 38589868 PMCID: PMC11003128 DOI: 10.1186/s12936-024-04902-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 03/05/2024] [Indexed: 04/10/2024] Open
Abstract
BACKGROUND Malaria remains a major global health problem often worsened by political instability and armed conflict. The purpose of the study was to explore community knowledge, attitudes and practices on malaria prevention, and to understand the burden of malaria and health-seeking behaviours of caregivers of children under-five in conflict-affected communities of the South West and Littoral Regions of Cameroon. METHODS A cross-sectional survey involving internally displaced persons (IDPS), host population, and their children under-five was conducted across 80 communities. The survey was conducted from May to June 2021. Participants were interviewed using a structured questionnaire. Malaria prevalence for children under-five was determined using rapid diagnostic tests (RDT) on blood samples. Association between variables and displacement status was measured using chi square test and multivariate logistic regression model was fitted to identify factors associated with adequate knowledge on malaria prevention. RESULTS A total of 2386 adults participated in the study and 1543 RDTs were conducted for children under-five. Adequate levels of knowledge and attitudes on malaria prevention was recorded among 1258 (52.9%) of the participants, with very strong evidence to suggest the level to be higher among the host (59.5%) compared to the IDPs (49.5%) and returnees (39.7%) (p < 0.001). Good practices towards malaria prevention was 43.3%, with very strong evidence indicating lower levels among IDPs (42.8%) and returnees (28.5%) compared to the host (49.4%) (p < 0.001). Malaria prevalence for children under-five was 54.0% and adequate health-seeking for suspected episodes of malaria was 53.0%, without any difference among IDPs (51.78%) and returnees (48.7%) compared to host populations (55.4%) (p = 0.154). Multivariate logistic regression model showed that there was quite strong evidence to suggest primary and secondary levels of education have higher odds of having correct knowledge of malaria prevention (adjusted odds ratio (AOR) 1.71, 95% confidence interval (CI): 1.11-2.64, p = 0.015 and AOR 1.80, 95% CI 1.15-2.82, p = 0.010 respectively). There was very strong evidence to suggest that owning a radio or a television was associated with greater odds of having a higher knowledge on malaria prevention (AOR 1.49, 95% CI 1.233-1.81, p = 0.000 and AOR 1.47, 95% CI 1.18-1.84, p = 0.001). CONCLUSION Over half of the population have correct knowledge and attitudes towards malaria prevention but gaps in complete knowledge remained. Some of the caregivers know the correct malaria preventive practices coupled with largely unsatisfactory treatment approaches and reflected by the high prevalence of malaria among their children. In order to effectively treat malaria, innovative strategies should target community participation.
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Affiliation(s)
- Elvis Asangbeng Tanue
- Reach Out Cameroon, Small Soppo, P.O Box 88, Buea, Cameroon.
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, P.O Box 63, Buea, Cameroon.
| | - Lundi-Anne Omam
- Reach Out Cameroon, Small Soppo, P.O Box 88, Buea, Cameroon
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB2 0SR, UK
| | - Glennis T Ayuk
- Reach Out Cameroon, Small Soppo, P.O Box 88, Buea, Cameroon
| | | | - Alain Metuge
- Reach Out Cameroon, Small Soppo, P.O Box 88, Buea, Cameroon
| | | | - Margaret Besem Ebob
- Reach Out Cameroon, Small Soppo, P.O Box 88, Buea, Cameroon
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Laura Donovan
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Ann-Sophie Stratil
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Helen Counihan
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Claude Ngwayu Nkfusai
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
- Department of Public Health, School of Nursing and Public Health, University of Kwa-Zulu Natal, Durban, South Africa
| | - Helen Hawkings
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Blanka Homolova
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Elizabeth Berryman
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Maxwell Kolawole
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Yakouba Zoungrana
- Malaria Consortium, the Green House, 244-254 Cambridge Heath Rd, London, E2 9DA, UK
| | - Dorothy Achu
- National Malaria Control Programme, Ministry of Public Health, P.O Box 14386, Yaounde, Cameroon
| | - Samuel Wanji
- Department for Microbiology and Parasitology, University of Buea, P.O Box 12, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
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5
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Ambe LA, Limunga E, Mbah CE, Adela N, Eric N, Ngoe M, Sone B, Lochnit G, Tachu JB, Wanji S, Taubert A, Hermosilla C, Kamena F. Identification and Characterization of Onchocerca volvulus Heat Shock Protein 70 ( OvHSP70) as Novel Diagnostic Marker of Onchocerciasis in Human Urine. Pathogens 2024; 13:293. [PMID: 38668248 PMCID: PMC11053476 DOI: 10.3390/pathogens13040293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 04/29/2024] Open
Abstract
Despite several decades of mass drug administration and elimination-related activities, human onchocerciasis still represents a major parasitic threat in endemic regions. Among the challenges encountered by the elimination program is the lack of a suitable diagnostic tool that is accurate and non-invasive. Currently used methods are either invasive or not suitable for monitoring large numbers of patients. Herein, we describe the identification and characterization of Onchocerca volvulus heat shock protein 70 (OvHSP70) as a novel diagnostic biomarker for human onchocerciasis, which can directly be detected in urine samples of infected patients. This nematode-specific antigen was identified through LC-MS after differential SDS-PAGE using urine-derived protein extracts from O. volvulus-infected patients in Cameroon. Polyclonal antibodies generated in rabbits after cloning and expression of OvHSP70 in Escherichia coli reliably differentiated between urine samples from infected- and uninfected patients in a hypoendemic area of human onchocerciasis. These results provide an excellent basis for further development of a non-invasive and scalable diagnostic assay for human onchocerciasis using urine samples. Such a urine-based diagnostic assay will be of major importance for the elimination program of human onchcerciasis in endemic countries.
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Affiliation(s)
- Lum Abienwi Ambe
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Elisabeth Limunga
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Clarisse Engowei Mbah
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Ngwewondo Adela
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Ndumu Eric
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Martha Ngoe
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Bertrand Sone
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Günter Lochnit
- Protein Analytics, Institute of Biochemistry, Faculty of Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany;
| | - Julius Babila Tachu
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon;
- Research Foundation in Tropical Disease and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Anja Taubert
- Biomedical Research Center Seltersberg (BFS), Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (A.T.); (C.H.)
| | - Carlos Hermosilla
- Biomedical Research Center Seltersberg (BFS), Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (A.T.); (C.H.)
| | - Faustin Kamena
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
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6
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Debrah LB, Arthur JF, Yeboah A, Owusu DO, Adankwah E, Acheampong I, Minadzi D, Lamptey M, Opoku VS, Aniagyei W, Vivekanandan MM, Abass MK, Gawusu A, Wanji S, Debrah AY, Jacobsen M, Phillips RO. Diversity of Culicoides in the middle belt of Ghana with Implications on the transmission of Mansonella perstans; a molecular approach. Parasit Vectors 2024; 17:123. [PMID: 38475862 DOI: 10.1186/s13071-024-06179-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/05/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Culicoides, also known as biting midges, carry pathogens which include Mansonella perstans. Mansonella perstans is a nematode parasite implicated in a number of disease outcomes. Even though a high prevalence of about 75% M. perstans infection has been recorded in some communities in the middle belt of Ghana, and a wide diversity of Culicoides species has been identified, the exact Culicoides species transmitting M. perstans in Ghana has not yet been deciphered. This study therefore aimed at assessing the species diversity of Culicoides and their role in the transmission of M. perstans in the middle belt of Ghana. METHODS Culicoides species were sampled from 11 communities in the Asante-Akim North and Sene West districts in the middle belt of Ghana. Centre for Disease Control (CDC) UV light traps, as well as human bait (i.e. human landing catch and engorged catch) methods were used to assess the species abundance and diversity of Culicoides in the study communities in the wet and dry season. A colorimetric Loop-Mediated Isothermal Amplification (LAMP) assay was performed to assess the vector competence of the various Culicoides species. RESULTS A total of 4810 Culicoides from 6 species were sampled. These included Culicoides inornatipennis, C. milnei, C. schultzei, C. grahamii, C. neavei, and C. imicola. Culicoides imicola was the most abundant species (56%) followed by C. grahamii (16%). Light traps sampled the most diverse species (6 species). Human landing catch and engorged catch methods identified three anthropophilic species, C. grahamii, C. milnei, and C. inornatipennis, with C. grahamii being the most anthropophilic with a peak biting time between the hours of 5 p.m. to 6 p.m. Generally, there was relatively higher species abundance in the wet than dry season. LAMP assay identified C. grahamii as the potential vector for M. perstans transmission in the middle belt of Ghana. CONCLUSIONS For the first time, we have demonstrated that C. grahamii is the potential competent vector for M. perstans transmission in the middle belt of Ghana. It is more abundant in the rainy season and has a peak biting time between the hours of 5 and 6 p.m.
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Grants
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
- DFG, JA 1479/9-1 Deutsche Forschungsgemeinschaft
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Affiliation(s)
- Linda Batsa Debrah
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana.
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana.
| | - Joseph F Arthur
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Augustine Yeboah
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Dorcas O Owusu
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | - Ernest Adankwah
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Medical Diagnostics, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Isaac Acheampong
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Medical Diagnostics, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Difery Minadzi
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | - Millicent Lamptey
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Vera Serwaa Opoku
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Wilfred Aniagyei
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | | | | | - Amidu Gawusu
- Sene West Health Directorate, Kwame Danso, Ghana
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Alexander Y Debrah
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- Department of Medical Diagnostics, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Marc Jacobsen
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, University Hospital Duesseldorf, Heinrich-Heine University, 40225, Duesseldorf, Germany
| | - Richard O Phillips
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
- School of Medicine and Dentistry, College of Health Sciences, KNUST, Kumasi, Ghana
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Ebai R, Kien CA, Fombad FF, Esofi F, Ouam E, Ntuh AN, Amambo GN, Gandjui VNT, Chunda VC, Nietcho F, Nchang LC, Magha C, Cho JF, Esum ME, Enyong PI, Pfarr K, Hoerauf A, Ritter M, Wanji S. Culicoides Species of the Rain Forest Belt of the Littoral Region of Cameroon: Their Incrimination in the Transmission of Mansonella perstans. Pathogens 2024; 13:146. [PMID: 38392884 PMCID: PMC10892414 DOI: 10.3390/pathogens13020146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/05/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Biting midges belonging to the genus Culicoides are tiny stout-shaped hematophagous insects and are thought to transmit the filarial nematode Mansonella perstans. Little is known about the Culicoides fauna in the rain forest belt of the Littoral Region of Cameroon. This study was designed to investigate the diversity, abundance and distribution of Culicoides spp. and their role as the purported vector(s) of M. perstans. Overnight light trap collections and human landing catches (HLCs) revealed eight species of Culicoides with C. grahamii being the most abundant species followed by C. milnei. Four anthropophilic species (C. inornatipennis, C. grahamii, C. fulvithorax and C. milnei) were determined by the HLCs with a higher abundance in the 4-6 p.m. collections. The drop trap technique and Mp419 LAMP assay confirmed C. milnei to be the most efficient vector in enabling the development of the microfilarial stage to the infective larval form of M. perstans. The LAMP assay also revealed that natural transmission of this nematode is fostered by C. milnei and C. grahamii in the wild. In conclusion, C. milnei was shown to be the main vector of M. perstans in the rain forest belt of the Littoral Region of Cameroon.
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Affiliation(s)
- Rene Ebai
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Chi Anizette Kien
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Fanny Fri Fombad
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Frederick Esofi
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Emmanuel Ouam
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Anna Ning Ntuh
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Glory Ngongeh Amambo
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Victor Narcisse Tchamatchoua Gandjui
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Valerine Chawa Chunda
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Franck Nietcho
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Lucy Cho Nchang
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Chefor Magha
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Jerome Fru Cho
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Mathias Eyong Esum
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Peter Ivo Enyong
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, 53127 Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, 53127 Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, 53127 Bonn, Germany
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, 53127 Bonn, Germany
| | - Samuel Wanji
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
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8
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Fadel AN, Ibrahim SS, Sandeu MM, Tatsinkou CGM, Menze BD, Irving H, Hearn J, Nagi SC, Weedall GD, Terence E, Tchapga W, Wanji S, Wondji CS. Exploring the molecular mechanisms of increased intensity of pyrethroid resistance in Central African population of a major malaria vector Anopheles coluzzii. Evol Appl 2024; 17:e13641. [PMID: 38410533 PMCID: PMC10895554 DOI: 10.1111/eva.13641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/14/2023] [Accepted: 01/01/2024] [Indexed: 02/28/2024] Open
Abstract
Molecular mechanisms driving the escalation of pyrethroid resistance in the major malaria mosquitoes of Central Africa remain largely uncharacterized, hindering effective management strategies. Here, resistance intensity and the molecular mechanisms driving it were investigated in a population of Anopheles coluzzii from northern Cameroon. High levels of pyrethroid and organochloride resistance were observed in An. coluzzii population, with no mortality for 1× permethrin; only 11% and 33% mortalities for 5× and 10× permethrin diagnostic concentrations, and <2% mortalities for deltamethrin and DDT, respectively. Moderate bendiocarb resistance (88% mortality) and full susceptibility to malathion were observed. Synergist bioassays with piperonyl butoxide recovered permethrin susceptibility, with mortalities increasing to 53.39%, and 87.30% for 5× and 10× permethrin, respectively, implicating P450 monooxygenases. Synergist bioassays with diethyl maleate (DEM) recovered permethrin and DDT susceptibilities (mortalities increasing to 34.75% and 14.88%, respectively), implicating glutathione S-transferases. RNA-seq-based genome-wide transcriptional analyses supported by quantitative PCR identified glutathione S-transferase, GSTe2 (RNA-seqFC = 2.93 and qRT-PCRFC = 8.4, p < 0.0043) and CYP450, CYP6Z2 (RNA-seqFC = 2.39 and qRT-PCRFC = 11.7, p < 0.0177) as the most overexpressed detoxification genes in the pyrethroid-resistant mosquitoes, compared to mosquitoes of the susceptible Ngousso colony. Other overexpressed genes include P450s, CYP6M2 (FC = 1.68, p < 0.0114), CYP4G16 (FC = 2.02, p < 0.0005), and CYP4G17 (FC = 1.86, p < 0.0276). While high frequency of the 1014F kdr mutation (50%) and low frequencies of 1014S (6.61%) and 1575Y (10.29%) were observed, no ace-1 mutation was detected in bendiocarb-resistant populations, suggesting the preeminent role of metabolic mechanism. Overexpression of metabolic resistance genes (including GSTe2 and CYP6Z2 known to confer resistance to multiple insecticides) in An. coluzzii from the Sudan Savannah of Cameroon highlights the need for alternative management strategies to reduce malaria burden in northern Cameroon.
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Affiliation(s)
- Amen N. Fadel
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Sulaiman S. Ibrahim
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of BiochemistryBayero UniversityKanoNigeria
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Maurice M. Sandeu
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and Infectious DiseasesSchool of Veterinary Medicine and SciencesUniversity of NgaoundéréNgaoundéréCameroon
| | | | | | - Helen Irving
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Jack Hearn
- Centre of Epidemiology and Planetary HealthNorth FacultyVeterinary & Animal ScienceScotland's Rural CollegeInvernessUK
| | - Sanjay C. Nagi
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Gareth D. Weedall
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | - Ebai Terence
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Williams Tchapga
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Samuel Wanji
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Charles S. Wondji
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
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Nkemngo FN, Raissa LW, Nguete DN, Ndo C, Fru-Cho J, Njiokou F, Wanji S, Wondji CS. Geographical emergence of sulfadoxine-pyrimethamine drug resistance-associated P. falciparum and P. malariae alleles in co-existing Anopheles mosquito and asymptomatic human populations across Cameroon. Antimicrob Agents Chemother 2023; 67:e0058823. [PMID: 37947766 PMCID: PMC10720508 DOI: 10.1128/aac.00588-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 09/28/2023] [Indexed: 11/12/2023] Open
Abstract
Malaria molecular surveillance remains critical in detecting and tracking emerging parasite resistance to anti-malarial drugs. The current study employed molecular techniques to determine Plasmodium species prevalence and characterize the genetic diversity of Plasmodium falciparum and Plasmodium malariae molecular markers of sulfadoxine-pyrimethamine resistance in humans and wild Anopheles mosquito populations in Cameroon. Anopheles mosquito collections and parasitological survey were conducted in villages to determine Plasmodium species infection, and genomic phenotyping of anti-folate resistance was accomplished by sequencing the dihydrofolate-reductase (dhfr) and dihydropteroate-synthase (dhps) genes of naturally circulating P. falciparum and P. malariae isolates. The malaria prevalence in Elende was 73.5% with the 5-15 years age group harboring significant P. falciparum (27%) and P. falciparum + P. malariae (19%) infections. The polymorphism breadth of the pyrimethamine-associated Pfdhfr marker revealed a near fixation (94%) of the triple-mutant -A16I51R59N108I164. The Pfdhps backbone mediating sulfadoxine resistance reveals a high frequency of the V431A436G437K540A581A613 alleles (20.8%). Similarly, the Pmdhfr N50K55L57R58S59S114F168I170 haplotype (78.4%) was predominantly detected in the asexual blood stage. In contrast, the Pmdhps- S436A437occured at 37.2% frequency. The combined quadruple N50K55L57R58S59S114F168I170_ S436G437K540A581A613 (31.9%) was the major circulating haplotype with similar frequency in humans and mosquitoes. This study highlights the increasing frequency of the P. malariae parasite mostly common in asymptomatic individuals with apparent P. falciparum infection. Interventions directed at reducing malaria transmission such as the scaling-up of SP are favoring the emergence and spread of multiple drug-resistant alleles between the human and mosquito host systems.
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Affiliation(s)
- Francis N. Nkemngo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Lymen W. Raissa
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Daniel N. Nguete
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Jerome Fru-Cho
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
- Centre for Infection Biology and Translational Research, Forzi Institute, Buea, Cameroon
| | - Flobert Njiokou
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Charles S. Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Doherty M, Grant JR, Pilotte N, Bennuru S, Fischer K, Fischer PU, Lustigman S, Nutman TB, Pfarr K, Hoerauf A, Unnasch TR, Hassan HK, Wanji S, Lammie PJ, Ottesen E, Mackenzie C, Williams SA. Optimized strategy for real-time qPCR detection of Onchocerca volvulus DNA in pooled Simulium sp. blackfly vectors. PLoS Negl Trop Dis 2023; 17:e0011815. [PMID: 38096317 PMCID: PMC10754622 DOI: 10.1371/journal.pntd.0011815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/28/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
BACKGROUND Onchocerca volvulus is a filarial parasite that is a major cause of dermatitis and blindness in endemic regions primarily in sub-Saharan Africa. Widespread efforts to control the disease caused by O. volvulus infection (onchocerciasis) began in 1974 and in recent years, following successful elimination of transmission in much of the Americas, the focus of efforts in Africa has moved from control to the more challenging goal of elimination of transmission in all endemic countries. Mass drug administration (MDA) with ivermectin has reached more than 150 million people and elimination of transmission has been confirmed in four South American countries, with at least two African countries having now stopped MDA as they approach verification of elimination. It is essential that accurate data for active transmission are used to assist in making the critical decision to stop MDA, since missing low levels of transmission and infection can lead to continued spread or recrudescence of the disease. METHODOLOGY/PRINCIPAL FINDINGS Current World Health Organization guidelines for MDA stopping decisions and post-treatment surveillance include screening pools of the Simulium blackfly vector for the presence of O. volvulus larvae using a PCR-ELISA-based molecular technique. In this study, we address the potential of an updated, practical, standardized molecular diagnostic tool with increased sensitivity and species-specificity by comparing several candidate qPCR assays. When paired with heat-stable reagents, a qPCR assay with a mitochondrial DNA target (OvND5) was found to be more sensitive and species-specific than an O150 qPCR, which targets a non-protein coding repetitive DNA sequence. The OvND5 assay detected 19/20 pools of 100 blackfly heads spiked with a single L3, compared to 16/20 for the O150 qPCR assay. CONCLUSIONS/SIGNIFICANCE Given the improved sensitivity, species-specificity and resistance to PCR inhibitors, we identified OvND5 as the optimal target for field sample detection. All reagents for this assay can be shipped at room temperature with no loss of activity. The qPCR protocol we propose is also simpler, faster, and more cost-effective than the current end-point molecular assays.
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Affiliation(s)
- Mary Doherty
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Jessica R. Grant
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Nils Pilotte
- Department of Biological Sciences, Quinnipiac University, Hamden, Connecticut, United States of America
| | - Sasisekhar Bennuru
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Kerstin Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Peter U. Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner-Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner-Site Bonn-Cologne, Bonn, Germany
| | - Thomas R. Unnasch
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida, United States of America
| | - Hassan K. Hassan
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida, United States of America
| | - Samuel Wanji
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Patrick J. Lammie
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Eric Ottesen
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Charles Mackenzie
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
- RLMF, The END Fund, New York, New York, United States of America
| | - Steven A. Williams
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, United States of America
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11
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Eyong EM, Njoh AA, Etutu SJM, Bachir HB, Ndoula ST, Saidou Y, Wanji S. Factors associated with a measles outbreak in three health districts of Cameroon in 2019: a cross-sectional study. Pan Afr Med J 2023; 46:41. [PMID: 38188886 PMCID: PMC10768634 DOI: 10.11604/pamj.2023.46.41.35832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 04/30/2023] [Indexed: 01/09/2024] Open
Abstract
Introduction measles is an infectious viral disease that affects susceptible individuals of all ages. It is a leading cause of death among young children globally due to suboptimal vaccination coverage. In 2019, measles outbreaks affected several parts of the world, including three health districts (HDs) of Cameroon's South West Region (SWR) experiencing armed conflict. Herein, we assessed the factors associated with the outbreak in the SWR. Methods we conducted a comparative study from March to August 2020. Data on study participants were compared between the three HDs that experienced a measles outbreak and three other HDs of the region that reported a case of measles but did not get into an outbreak. Records on vaccination between 2015 and 2019 were reviewed. Results information was obtained from 56 participants with known measles status, 32 from outbreak districts, and 24 from non-outbreak districts. The population in the outbreak group was more likely to have traveled from an area in a measles outbreak (OR 2, 95%CI 1.1-11.20). There was a suboptimal availability of measles vaccines in both categories of districts compared to the needs, and there was a downward trend in vaccination coverage in both groups. In addition, vaccines were more exposed to extreme temperatures in HDs with the outbreak (P<0.01) from 2015 to 2019. We found no statistically significant difference between both groups concerning the preexisting comorbidities of participants. Conclusion there is an urgent need to improve the cold chain and intensify vaccination activities in these districts.
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Affiliation(s)
- Esum Mathias Eyong
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea Cameroon
| | - Andreas Ateke Njoh
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea Cameroon
- School of Global Health and Bioethics, Euclid University, Bangui, Central African Republic
- Expanded program on immunization, Ministry of Public Health, Yaoundé, Cameroon
| | - Sophie Jose Molua Etutu
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea Cameroon
| | - Hassan Ben Bachir
- Department of Family Health, Ministry of Public Health, Yaoundé, Cameroon
| | | | - Yauba Saidou
- Clinton Health Access Initiative, Yaoundé, Cameroon
- Institute of Global Health, University of Siena, Siena, Italy
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea Cameroon
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12
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Neidhöfer C, Nkwetta DL, Fuen BR, Yenban NF, Mbiatong N, Nchanji GT, Korir P, Wetzig N, Sieber M, Thiele R, Parcina M, Klarmann-Schulz U, Hoerauf A, Wanji S, Ritter M. Tropical leg lymphedema caused by podoconiosis is associated with increased colonisation by anaerobic bacteria. Sci Rep 2023; 13:13785. [PMID: 37612446 PMCID: PMC10447442 DOI: 10.1038/s41598-023-40765-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 08/16/2023] [Indexed: 08/25/2023] Open
Abstract
The non-filarial and non-communicable disease podoconiosis affects around 4 million people and is characterized by severe leg lymphedema accompanied with painful intermittent acute inflammatory episodes, called acute dermatolymphangioadenitis (ADLA) attacks. Risk factors have been associated with the disease but the mechanisms of pathophysiology remain uncertain. Lymphedema can lead to skin lesions, which can serve as entry points for bacteria that may cause ADLA attacks leading to progression of the lymphedema. However, the microbiome of the skin of affected legs from podoconiosis individuals remains unclear. Thus, we analysed the skin microbiome of podoconiosis legs using next generation sequencing. We revealed a positive correlation between increasing lymphedema severity and non-commensal anaerobic bacteria, especially Anaerococcus provencensis, as well as a negative correlation with the presence of Corynebacterium, a constituent of normal skin flora. Disease symptoms were generally linked to higher microbial diversity and richness, which deviated from the normal composition of the skin. These findings show an association of distinct bacterial taxa with lymphedema stages, highlighting the important role of bacteria for the pathogenesis of podoconiosis and might enable a selection of better treatment regimens to manage ADLA attacks and disease progression.
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Affiliation(s)
- Claudio Neidhöfer
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Derick Lekealem Nkwetta
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Bangsi Rose Fuen
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Njodzeka Flora Yenban
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Nancielle Mbiatong
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Gordon Takop Nchanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Patricia Korir
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Nina Wetzig
- Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany
| | - Martin Sieber
- Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany
| | - Ralf Thiele
- Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany
| | - Marijo Parcina
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), Neglected Tropical Disease, Partner Site, Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), Neglected Tropical Disease, Partner Site, Bonn-Cologne, Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site, Bonn, Bonn, Germany
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany.
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13
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Nkemngo FN, W G Raissa L, Nebangwa DN, Nkeng AM, Kengne A, Mugenzi LMJ, Fotso-Toguem YG, Wondji MJ, Shey RA, Nguiffo-Nguete D, Fru-Cho J, Ndo C, Njiokou F, Webster JP, Wanji S, Wondji CS. Epidemiology of malaria, schistosomiasis, and geohelminthiasis amongst children 3-15 years of age during the dry season in Northern Cameroon. PLoS One 2023; 18:e0288560. [PMID: 37523402 PMCID: PMC10389741 DOI: 10.1371/journal.pone.0288560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 06/29/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND The double burden of malaria and helminthiasis in children poses an obvious public health challenge, particularly in terms of anemia morbidity. While both diseases frequently geographically overlap, most studies focus on mono-infection and general prevalence surveys without molecular analysis. The current study investigated the epidemiological determinants of malaria, schistosomiasis, and geohelminthiasis transmission among children in the North Region of Cameroon. METHODOLOGY School and pre-school children aged 3-15 year-of-age were enrolled from three communities in March 2021 using a community cross-sectional design. Capillary-blood samples were obtained, and each was examined for malaria parasites using rapid-diagnostic-test (RDT), microscopy, and PCR while hemoglobin level was measured using a hemoglobinometer. Stool samples were analyzed for Schistosoma mansoni, S. guineensis, and soil-transmitted-helminthiasis (STH) infections using the Kato Katz method, and urine samples were assessed for the presence of S. haematobium eggs (including hybrids) using the standard urine filtration technique. RESULT A malaria prevalence of 56% (277/495) was recorded by PCR as opposed to 31.5% (156/495) by microscopy and 37.8% (186/495) by RDT. Similarly, schistosomiasis was observed at prevalence levels of up to 13.3% (66/495) overall [S. haematobium (8.7%); S. mansoni (3.8%); mixed Sh/Sm (0.6%); mixed Sh/Sm/Sg (0.2%). Both infections were higher in males and the 3-9 year-of-age groups. A high frequency of PCR reported P. falciparum mono-infection of 81.9% (227/277) and mixed P. falciparum/P. malariae infection of 17.3% (48/277) was observed. Malaria-helminths co-infections were observed at 13.1% (65/495) with marked variation between P. falciparum/S. haematobium (50.8%, 33/65); P. falciparum/S. mansoni (16.9%, 11/65) and P. falciparum/Ascaris (9.2%, 6/65) (χ2 = 17.5, p = 0.00003). Anemia prevalence was 32.9% (163/495), categorically associated with P. falciparum (45.8%, 104/227), Pf/Sh (11.5%, 26/227), and Pf/Sm (3.9%, 9/227) polyparasitism. CONCLUSION Polyparasitism with malaria and helminth infections is common in school-aged children despite periodic long-lasting insecticide-treated nets (LLINs) distribution and regular school-based praziquantel (for schistosomiasis) and albendazole (for STH) campaigns. Co-existence of Plasmodium parasites and helminths infections notably Schistosoma species among children may concurrently lead to an increase in Plasmodium infection with an enhanced risk of anemia, highlighting the necessity of an integrated approach for disease control interventions.
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Affiliation(s)
- Francis N Nkemngo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Lymen W G Raissa
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Derrick N Nebangwa
- Faculty of Life Science and Medicine, King's College London, New Hunt's House, London, United Kingdom
| | - Asongha M Nkeng
- Centre for Infection Biology and Translational Research (CIBiT), Forzi Institute, Buea, Cameroon
- Department of Sociology & Anthropology, Faculty of Social and Management Sciences, University of Buea, Buea, Cameroon
| | - Alvine Kengne
- Department of Animal Biology and Physiology, Parasitology and Ecology Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | | | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Robert A Shey
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | | | - Jerome Fru-Cho
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Parasitology and Ecology Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Joanne P Webster
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Herts, United Kingdom
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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14
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Hedtke SM, Choi YJ, Kode A, Chalasani GC, Sirwani N, Jada SR, Hotterbeekx A, Mandro M, Siewe Fodjo JN, Amambo GN, Abong RA, Wanji S, Kuesel AC, Colebunders R, Mitreva M, Grant WN. Assessing Onchocerca volvulus Intensity of Infection and Genetic Diversity Using Mitochondrial Genome Sequencing of Single Microfilariae Obtained before and after Ivermectin Treatment. Pathogens 2023; 12:971. [PMID: 37513818 PMCID: PMC10385737 DOI: 10.3390/pathogens12070971] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/16/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Onchocerciasis is a neglected tropical disease targeted for elimination using ivermectin mass administration. Ivermectin kills the microfilariae and temporarily arrests microfilariae production by the macrofilariae. We genotyped 436 microfilariae from 10 people each in Ituri, Democratic Republic of the Congo (DRC), and Maridi County, South Sudan, collected before and 4-5 months after ivermectin treatment. Population genetic analyses identified 52 and 103 mitochondrial DNA haplotypes among the microfilariae from DRC and South Sudan, respectively, with few haplotypes shared between people. The percentage of genotype-based correct assignment to person within DRC was ~88% and within South Sudan ~64%. Rarefaction and extrapolation analysis showed that the genetic diversity in DRC, and even more so in South Sudan, was captured incompletely. The results indicate that the per-person adult worm burden is likely higher in South Sudan than DRC. Analyses of haplotype data from a subsample (n = 4) did not discriminate genetically between pre- and post-treatment microfilariae, confirming that post-treatment microfilariae are not the result of new infections. With appropriate sampling, mitochondrial haplotype analysis could help monitor changes in the number of macrofilariae in a population as a result of treatment, identify cases of potential treatment failure, and detect new infections as an indicator of continuing transmission.
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Affiliation(s)
- Shannon M. Hedtke
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Young-Jun Choi
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA; (Y.-J.C.); (M.M.)
| | - Anusha Kode
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Gowtam C. Chalasani
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Neha Sirwani
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | | | - An Hotterbeekx
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Michel Mandro
- Provincial Health Division Ituri, Ministry of Health, Bunia P.O. Box 57, Democratic Republic of the Congo;
| | - Joseph N. Siewe Fodjo
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Glory Ngongeh Amambo
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
| | - Raphael A. Abong
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
- Research Foundation for Tropical Diseases and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Samuel Wanji
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
- Research Foundation for Tropical Diseases and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1202 Geneva, Switzerland;
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Makedonka Mitreva
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA; (Y.-J.C.); (M.M.)
| | - Warwick N. Grant
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
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15
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Nkwetta DL, Fuen BR, Yenban NF, Mbiatong N, Nchanji GT, Bonekeh J, Ndzeshang BL, Gandjui NVT, Fombad FF, Klarmann-Schulz U, Esum ME, Njouendou AJ, Cho JF, Hoerauf A, Ritter M, Wanji S. Phenotypical characterization, and antibiotics susceptibility patterns of skin bacteria found in podoconiosis patients in the North West Region of Cameroon. BMC Microbiol 2023; 23:189. [PMID: 37460950 PMCID: PMC10351198 DOI: 10.1186/s12866-023-02923-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND Podoconiosis, a non-infectious disease originating from long-term exposure of bare feet to irritant red clay soil is a lifelong, disabling disease with no specific diagnostic tool, classified into 5 stages based on the severity of leg swelling (lymphoedema). Secondary bacterial infections have been suggested to cause acute dermatolymphangioadenitis (ADLA) attacks and drive disease progression. Although the North West Region of Cameroon has a proven history of podoconiosis endemicity, the bacterial composition of lymphoedema due to this condition has not been studied. Thus, this study investigated the leg bacterial diversity of patients who suffered from the lymphoedema and their susceptibility pattern to selected antibiotics. METHODS A cross-sectional study was carried out in which podoconiosis affected and non-lymphoedema individuals living in the same community were purposively selected. Samples were collected by swabbing the skin between the toes and around the anklebone, then cultured and sub-cultured on nutrient agar to obtain pure isolates. The cultured isolates were then morphologically and biochemically classified using microscopy and analytic profile index test kits, respectively. The disk diffusion technique was used to determine antibiotic susceptibility. RESULTS Thirty-three participants were recruited, and 249 bacterial isolates were characterized into 29 genera, 60 species; with 30 (50%) being gram positive rods, 19 (31.7%) gram positive cocci, and 11 (18.3%) gram negative rods. Thirteen gram positive rods, fifteen gram positive cocci, and eight gram negative rods of bacterial species were found only in podoconiosis individuals among which Cellulomonas spp / Microbacterium spp. (2.8%), Staphylococcus lentus (3.3%), and Burkholderia cepacia (4.0%) dominated. 90% (90%) of the bacterial isolates were sensitive to doxycycline, whereas ampicillin had a high level of intermediate resistance, and penicillin G had the greatest resistant profile. CONCLUSION Our findings show that 94 (37.8%) out of 249 described bacterial isolates were exclusively found in the legs of podoconiosis individuals, and their susceptibility pattern to antibiotics was similar to that of others.
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Affiliation(s)
- Derick Lekealem Nkwetta
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Bangsi Rose Fuen
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Njodzeka Flora Yenban
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Nancielle Mbiatong
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Gordon Takop Nchanji
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - John Bonekeh
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Bertrand Lontum Ndzeshang
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Narcisse Victor Tchamatchoua Gandjui
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Fanny Fri Fombad
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Centre for Infection Research (DZIF), Neglected Tropical Disease, partner site, Bonn- Cologne, Bonn, Germany
| | - Mathias Eyong Esum
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
- Department of Biomedical Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Jerome Fru Cho
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site, Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon.
- The Peoples' Hope Medical Care Centre (PHOMECC), Bamenda, Cameroon.
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16
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Lenz B, Andrew BA, Ritter M, Karunakaran I, Gandjui NVT, Nchang LC, Surendar J, Ebob AOB, Ehrens A, Klarmann-Schulz U, Ricchiuto A, Kuehlwein JM, Fombad FF, Ngwa AM, Katcho TD, Hoerauf A, Wanji S, Hübner MP. The design and development of a study protocol to investigate Onchocerca volvulus, Loa loa and Mansonella perstans-mediated modulation of the metabolic and immunological profile in lean and obese individuals in Cameroon. PLoS One 2023; 18:e0285689. [PMID: 37267236 DOI: 10.1371/journal.pone.0285689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/10/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Life-style metabolic diseases are steadily rising, not only in developed countries, but also in low- and middle-income countries, presenting a global health problem. Metabolic disorders like type 2 diabetes and cardiovascular diseases are among the ten leading causes of death defined by the WHO in 2019. Results from animal and observational human studies suggest a connection between the decline in human helminth infections and rise of life-style-associated metabolic diseases in developing regions. This trial was designed to investigate filarial infections and their impact on metabolic diseases in Cameroon. We hypothesize that the induction of regulatory immune responses during filarial infection reduces obesity-induced low-grade inflammatory immune responses and thereby improves metabolic parameters, whereas anthelmintic treatment abolishes this protective effect. METHODS/DESIGN Participants infected with Mansonella perstans, Onchocerca volvulus and/or Loa loa being lean (BMI <25), overweight (BMI >25 and <30) or clinically obese (BMI ≥30) from Littoral regions of Cameroon will be evaluated for their parasitological, immunological, metabolic and biochemical profile before and after treatment of their parasitic infections. Anthropomorphic measurements and a detailed questionnaire will complement our analysis. The investigation will assess blood immune cell populations, serum adipokines and cytokines that could be influenced by the parasite infection and/or metabolic diseases. Further, parameters like blood glucose, homeostatic model assessment of insulin resistance (HOMA-IR), circulating lipids and circulating makers of liver function will be monitored. Parameters will be assessed before treatment, 12 and 18 months after treatment. CONCLUSION The focus of this study is to obtain a comprehensive metabolic profile of the participants in rural areas of Cameroon and to investigate the relationship between filarial immunomodulation and metabolic diseases. This study will elucidate the effect of anti-filarial treatment on the metabolic and immunological parameters that partake in the development of insulin resistance, narrowing in on a potential protective effect of filarial infections on metabolic diseases. TRIAL REGISTRATION doi.org/10.1186/ISRCTN43845142, ISRCTN43845142 February 2020 Trial title Effects of filarial parasite infection on type 2 diabetes Issue date: 27.10.22, V.1.
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Affiliation(s)
- Benjamin Lenz
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Beng Amuam Andrew
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Indulekha Karunakaran
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Narcisse Victor Tchamatchoua Gandjui
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Lucy Cho Nchang
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Jayagopi Surendar
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Anita Obi Bate Ebob
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Alexandra Ehrens
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Bonn, Germany
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Bonn, Germany
| | - Arcangelo Ricchiuto
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Janina M Kuehlwein
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Bonn, Germany
| | - Fanny Fri Fombad
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Ambe Marius Ngwa
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Tatiana Djikeussi Katcho
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Bonn, Germany
| | - Samuel Wanji
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Bonn, Germany
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17
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Sinha A, Li Z, Poole CB, Ettwiller L, Lima NF, Ferreira MU, Fombad FF, Wanji S, Carlow CKS. Multiple lineages of nematode-Wolbachia symbiosis in supergroup F and convergent loss of bacterioferritin in filarial Wolbachia. Genome Biol Evol 2023:7156662. [PMID: 37154102 DOI: 10.1093/gbe/evad073] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 04/14/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023] Open
Abstract
The intracellular endosymbiotic proteobacteria Wolbachia have evolved across the phyla nematoda and arthropoda. In Wolbachia phylogeny, supergroup F is the only clade known so far with members from both arthropod and filarial nematode hosts and therefore can provide unique insights into their evolution and biology. In this study, 4 new supergroup F Wolbachia genomes have been assembled using a metagenomic assembly and binning approach, wMoz and wMpe from the human filarial parasites Mansonella ozzardi and Mansonella perstans, and wOcae and wMoviF from the blue mason bee Osmia caerulescens and the sheep ked Melophagus ovinus respectively. A comprehensive phylogenomic analysis revealed two distinct lineages of filarial Wolbachia in supergroup F, indicating multiple horizontal transfer events between arthropod and nematode hosts. The analysis also reveals that the evolution of Wolbachia-filaria symbioses is accompanied by a convergent pseudogenization and loss of the bacterioferritin gene, a phenomenon found to be shared by all filarial Wolbachia, even those outside supergroup F. These observations indicate that differences in heme metabolism might be a key feature distinguishing filarial and arthropod Wolbachia. The new genomes provide a valuable resource for further studies on symbiosis, evolution, and the discovery of new antibiotics to treat mansonellosis.
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Affiliation(s)
- Amit Sinha
- New England Biolabs, Ipswich, Massachusetts, 01938, USA
| | - Zhiru Li
- New England Biolabs, Ipswich, Massachusetts, 01938, USA
| | | | | | - Nathália F Lima
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Fanny F Fombad
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
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18
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Ekanya R, Beng AA, Anim MA, Pangwoh YZ, Dibando OE, Gandjui NVT, Awah AR, Amambo GN, Nchanji GT, Ndzeshang BL, Nji TM, Fombad FF, Njouendou AJ, Eyong EM, Cho JF, Eyong PA, Deribe K, Ngum NH, Golden A, Wanji S. Concordance between Ov16 Rapid Diagnostic Test(RDT) and Ov16 Enzyme-Linked Immunosorbent Assay (ELISA) for the Diagnosis of Onchocerciasis in Areas of Contrasting Endemicity in Cameroon. Parasite Epidemiol Control 2023; 21:e00290. [PMID: 36875175 PMCID: PMC7614264 DOI: 10.1016/j.parepi.2023.e00290] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
The diagnosis of onchocerciasis in endemic areas has been demanding given the need to replace the invasive skin snip method with a more sensitive and specific rapid point-of-contact tool. Filarial antigen detection tests are better alternative methods in diagnosing Onchocercal infections, as they detect infections and could be used to monitor transmission in endemic areas following mass drug administration. With the shift in paradigme from control to elimination, a rapid point- of-contact tool is required to support elimination programs. This was a cross-sectional, community-based study conducted in 50 villages selected from six health districts using a systematic sampling technique. Individuals ≥17 years who had lived in the community for a duration of 5 years and above provided blood specimens for IgG4 antibodies testing against O. volvulus antigens. Data were analyzed using SPSS v.20 and expectation maximization to classify optical densities for positive and negative samples from ELISA results. The kappa statistics was used to measure the level of agreement between the two tests. In a total of 5001 participants which were recruited for the study, 4416 (88.3 %) participant samples passed the plate quality control criteria and were considered for the test comparison analysis. Out of the 4416 participants, 292 (6.6 %) tested positive with Ov16 RDT and 310 (7.0 %) with Ov16 ELISA. All those who tested positive with the rapid test agreed positive with ELISA. The overall percentage agreement was 99.2 %, the Kappa score of 0.936. The results obtained indicate an excellent agreement between ELISA and RDT as measured by kappa (0.936) which was statistically significant (P<0.001). Our experience with the Ov16 ELISA biplex rapid test was favorable. However, the Ov16 RDT test may be more appropriate to use in remote areas for the point diagnosis of onchocerciasis in view towards achieving elimination in Africa.
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Affiliation(s)
- Relindis Ekanya
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Amuam Andrew Beng
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Muwah Anastacia Anim
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Yokyu Zachary Pangwoh
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Obie Elisabeth Dibando
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Narcisse Victor Tchamatchoua Gandjui
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Abong Raphael Awah
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Glory N. Amambo
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Gordon Takop Nchanji
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Bertrand Lontum Ndzeshang
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Theobald Mue Nji
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Esum Mathias Eyong
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Jerome Fru Cho
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Peter A. Eyong
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Children's Investment Fund Foundation, Addis Ababa, Ethiopia
- Brighton and Sussex Medical School, Department of Global Health and Infection, Brighton, UK
| | | | | | - Samuel Wanji
- Parasite and vector biology research unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment, (REFOTDE), Buea, Cameroon
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19
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Sinha A, Li Z, Poole CB, Morgan RD, Ettwiller L, Lima NF, Ferreira MU, Fombad FF, Wanji S, Carlow CKS. Genomes of the human filarial parasites Mansonella perstans and Mansonella ozzardi. Front Trop Dis 2023. [DOI: 10.3389/fitd.2023.1139343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
The filarial parasites Mansonella ozzardi and Mansonella perstans, causative agents of mansonellosis, infect hundreds of millions of people worldwide, yet remain among the most understudied of the human filarial pathogens. M. ozzardi is highly prevalent in Latin American countries and Caribbean Islands, while M. perstans is predominantly found in sub-Saharan Africa as well as in a few areas in South America. In addition to the differences in their geographical distribution, the two parasites are transmitted by different insect vectors, as well as exhibit differences in their responses to commonly used anthelminthic drugs. The lack of genome information has hindered investigations into the biology and evolution of Mansonella parasites and understanding the molecular basis of the clinical differences between species. In the current study, high quality genomes of two independent clinical isolates of M. perstans from Cameroon and two M. ozzardi isolates one from Brazil and one from Venezuela are reported. The genomes are approximately 76 Mb in size, encode about 10,000 genes each, and are largely complete based on BUSCO scores of about 90%, similar to other completed filarial genomes. These sequences represent the first genomes from Mansonella parasites and enabled a comparative genomic analysis of the similarities and differences between Mansonella and other filarial parasites. Horizontal DNA transfers (HDT) from mitochondria (nuMTs) as well as transfers from genomes of endosymbiotic Wolbachia bacteria (nuWTs) to the host nuclear genome were identified and analyzed. Sequence comparisons and phylogenetic analysis of known targets of anti-filarial drugs diethylcarbamazine (DEC), ivermectin and mebendazole revealed that all known target genes were present in both species, except for the DEC target encoded by gon-2 gene, which is fragmented in genome assemblies from both M. ozzardi isolates. These new reference genome sequences will provide a valuable resource for further studies on biology, symbiosis, evolution and drug discovery.
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Nditanchou R, Dixon R, Atekem K, Akongo S, Biholong B, Ayisi F, Nwane P, Wilhelm A, Basnet S, Selby R, Wanji S, Bakajika D, Oye J, Kamgno J, Boakye D, Schmidt E, Senyonjo L. Acceptability of test and treat with doxycycline against Onchocerciasis in an area of persistent transmission in Massangam Health District, Cameroon. PLoS Negl Trop Dis 2023; 17:e0011185. [PMID: 37018235 PMCID: PMC10075443 DOI: 10.1371/journal.pntd.0011185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 02/21/2023] [Indexed: 04/06/2023] Open
Abstract
The main onchocerciasis elimination strategy is annual Community-Directed Treatment with ivermectin (CDTi). However, as a response to persistent high infection prevalence in Massangam Health District in Cameroon, two rounds of alternative treatments including biannual CDTi, ground larviciding and test and treat with doxycycline (TTd) were implemented. This led to a significant prevalence reduction from 35.7% to 12.3% (p<0.001) as reported by Atekem and colleagues. Here we report on the acceptability of TTd component based on qualitative and quantitative data. The TTd involved microscopic examination for microfilaria in skin biopsy and those infected were offered doxycycline 100 mg daily for 35 days by community-directed distributors (CDDs). Participation level was significantly high with 54% of eligible population (age > 8, not pregnant, not breastfeeding, not severely ill,) participating in the test in each round, increasing to 83% over the two rounds. Factors associated with non-participation included mistrust, being female; being younger than 26 years; short stay in the community; and belonging to semi-nomadic sub population due to their remote and disperse settlement, discrimination, their non selection as CDD, and language and cultural barriers. Treatment coverage was high -71% in round 1 and 83% in round 2. People moving away between testing and treatment impacted treatment coverage. Some participants noted mismatch between symptoms and test result; and that ivermectin is better than doxycycline, while others favoured doxycycline. CDD worried about work burden with unmatching compensation. Overall, TTd participation was satisfactory. But can be improved through reinforcing sensitisation, reducing time between test and treatment; combining TTd and CDTi in one outing; augmenting CDDs compensation and/or weekly visit; exploring for frequently excluded populations and adapting strategies to reach them; and use of a sensitive less invasive test.
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Affiliation(s)
| | - Ruth Dixon
- Sightsavers, Haywards Heath, United Kingdom
| | | | | | - Benjamin Biholong
- National Programme for the Fight against Onchocerciasis and Lymphatic Filariasis, Ministry of Public Health, Yaoundé, Cameroon
| | - Franklin Ayisi
- National Programme for the Fight against Onchocerciasis and Lymphatic Filariasis, Ministry of Public Health, Yaoundé, Cameroon
| | - Philippe Nwane
- Filariasis and other Tropical Neglected Diseases Research Center, Yaoundé, Cameroon
| | | | | | | | - Samuel Wanji
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Cameroon
| | - Didier Bakajika
- WHO/Regional Office for Africa, Brazzaville, Republic of the Congo
| | - Joseph Oye
- Sightsavers, Cameroon Country Office, Cameroon
| | - Joseph Kamgno
- Filariasis and other Tropical Neglected Diseases Research Center, Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Daniel Boakye
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
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Petralia LMC, van Diepen A, Nguyen DL, Lokker LA, Sartono E, Bennuru S, Nutman TB, Pfarr K, Hoerauf A, Wanji S, Foster JM, Hokke CH. Unraveling cross-reactivity of anti-glycan IgG responses in filarial nematode infections. Front Immunol 2023; 14:1102344. [PMID: 36949937 PMCID: PMC10026598 DOI: 10.3389/fimmu.2023.1102344] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/02/2023] [Indexed: 03/08/2023] Open
Abstract
Parasitic nematodes responsible for filarial diseases cause chronic disablement in humans worldwide. Elimination programs have substantially reduced the rate of infection in certain areas, but limitations of current diagnostics for population surveillance have been pointed out and improved assays are needed to reach the elimination targets. While serological tests detecting antibodies to parasite antigens are convenient tools, those currently available are compromised by the occurrence of antibodies cross-reactive between nematodes, as well as by the presence of residual antibodies in sera years after treatment and clearance of the infection. We recently characterized the N-linked and glycosphingolipid derived glycans of the parasitic nematode Brugia malayi and revealed the presence of various antigenic structures that triggered immunoglobulin G (IgG) responses in infected individuals. To address the specificity of IgG binding to these glycan antigens, we screened microarrays containing Brugia malayi glycans with plasma from uninfected individuals and from individuals infected with Loa loa, Onchocerca volvulus, Mansonella perstans and Wuchereria bancrofti, four closely related filarial nematodes. IgG to a restricted subset of cross-reactive glycans was observed in infection plasmas from all four species. In plasma from Onchocerca volvulus and Mansonella perstans infected individuals, IgG binding to many more glycans was additionally detected, resulting in total IgG responses similar to the ones of Brugia malayi infected individuals. For these infection groups, Brugia malayi, Onchocerca volvulus and Mansonella perstans, we further studied the different IgG subclasses to Brugia malayi glycans. In all three infections, IgG1 and IgG2 appeared to be the major subclasses involved in response to glycan antigens. Interestingly, in Brugia malayi infected individuals, we observed a marked reduction in particular in IgG2 to parasite glycans post-treatment with anthelminthic, suggesting a promising potential for diagnostic applications. Thus, we compared the IgG response to a broad repertoire of Brugia malayi glycans in individuals infected with various filarial nematodes. We identified broadly cross-reactive and more specific glycan targets, extending the currently scarce knowledge of filarial nematode glycosylation and host anti-glycan antibody response. We believe that our initial findings could be further exploited to develop disease-specific diagnostics as part of an integrated approach for filarial disease control.
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Affiliation(s)
- Laudine M. C. Petralia
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
- Division of Protein Expression & Modification, New England Biolabs, Ipswich, MA, United States
| | - Angela van Diepen
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Dieu-Linh Nguyen
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Lena A. Lokker
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Erliyani Sartono
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Sasisekhar Bennuru
- Laboratory of Parasitic Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kenneth Pfarr
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Samuel Wanji
- Epidemiology and Control of Infectious Diseases, Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Jeremy M. Foster
- Division of Protein Expression & Modification, New England Biolabs, Ipswich, MA, United States
| | - Cornelis H. Hokke
- Department of Parasitology, Leiden University – Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
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22
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Karunakaran I, Ritter M, Pfarr K, Klarmann-Schulz U, Debrah AY, Debrah LB, Katawa G, Wanji S, Specht S, Adjobimey T, Hübner MP, Hoerauf A. Filariasis research - from basic research to drug development and novel diagnostics, over a decade of research at the Institute for Medical Microbiology, Immunology and Parasitology, Bonn, Germany. Front Trop Dis 2023; 4:1126173. [PMID: 38655130 PMCID: PMC7615856 DOI: 10.3389/fitd.2023.1126173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Filariae are vector borne parasitic nematodes, endemic in tropical and subtropical regions causing avoidable infections ranging from asymptomatic to stigmatizing and disfiguring disease. The filarial species that are the major focus of our institution's research are Onchocerca volvulus causing onchocerciasis (river blindness), Wuchereria bancrofti and Brugia spp. causing lymphatic filariasis (elephantiasis), Loa loa causing loiasis (African eye worm), and Mansonella spp causing mansonellosis. This paper aims to showcase the contribution of our institution and our collaborating partners to filarial research and covers decades of long research spanning basic research using the Litomosoides sigmodontis animal model to development of drugs and novel diagnostics. Research with the L. sigmodontis model has been extensively useful in elucidating protective immune responses against filariae as well as in identifying the mechanisms of filarial immunomodulation during metabolic, autoimmune and infectious diseases. The institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany has also been actively involved in translational research in contributing to the identification of new drug targets and pre-clinical drug research with successful and ongoing partnership with sub-Saharan Africa, mainly Ghana (the Kumasi Centre for Collaborative Research (KCCR)), Cameroon (University of Buea (UB)) and Togo (Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires (LAMICODA)), Asia and industry partners. Further, in the direction of developing novel diagnostics that are sensitive, time, and labour saving, we have developed sensitive qPCRs as well as LAMP assays and are currently working on artificial intelligence based histology analysis for onchocerciasis. The article also highlights our ongoing research and the need for novel animal models and new drug targets.
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Affiliation(s)
- Indulekha Karunakaran
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Kenneth Pfarr
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Alexander Yaw Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Kumasi Center for Collaborative Research (KCCR), Kumasi, Ghana
| | - Linda Batsa Debrah
- Kumasi Center for Collaborative Research (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Gnatoulma Katawa
- Unité de Recherche en Immunologie et Immunomodulation (UR2IM)/Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires (LAMICODA), Ecole Supérieure des Techniques Biologiques et Alimentaires, Université de Lomé, Lomé, Togo
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Sabine Specht
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Tomabu Adjobimey
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
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23
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Amambo GN, Innocentia N, Abong RA, Fombad FF, Njouendou AJ, Nietcho F, Ekanya R, Kien CA, Ebai R, Lenz B, Ritter M, Esum ME, Deribe K, Cho JF, Beng AA, Enyong PI, Li Z, Hübner MP, Pfarr K, Hoerauf A, Carlow C, Wanji S. Application of loop mediated isothermal amplification (LAMP) assays for the detection of Onchocerca volvulus, Loa loa and Mansonella perstans in humans and vectors. Front Trop Dis 2023; 3:1016176. [PMID: 36684508 PMCID: PMC7614089 DOI: 10.3389/fitd.2022.1016176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Conventional diagnosis of filarial infections is based on morphological identification of microfilariae using light microscopy and requires considerable expertise, is time-consuming, and can be subjective. Loop-mediated isothermal amplification (LAMP) has advantages over microscopy or PCR because of its operational simplicity, rapidity and versatility of readout options. LAMP assays represent a major step forward in improved filarial diagnostic tools suitable for low resource settings and field applicability. The study goal was to retrospectively evaluate the performance and suitability of the O-150, RF4, and Mp419 LAMP assays for diagnosing Onchocerca volvulus, Loa loa and Mansonella perstans infections, respectively, in humans and vectors under experimental and natural field conditions. Surveys were conducted in four health districts of Cameroon using skin snip and thick blood film methods to detect skin (O. volvulus) and blood (L. loa and M. perstans) dwelling microfilaria in humans. Engorged vectors (Simulium spp., Chrysops spp., and Culicoides spp.) were evaluated by LAMP. Dissected, wild-caught vectors were also analyzed. LAMP showed a prevalence of 40.4% (O. volvulus), 17.8% (L. loa) and 36.6% (M. perstans) versus 20.6% (O. volvulus), 17.4% (L. loa) and 33.8% (M. perstans) with microscopy. Simulium spp. were dissected for microscopy and pooled for LAMP. The O-150 LAMP assay infection rate was 4.3% versus 4.1% by microscopy. Chrysops spp. were dissected and analyzed individually in the LAMP assay. The RF4 LAMP assay infection rate was 23.5% versus 3.3% with microscopy. The RF4 LAMP assay also detected parasites in Chrysops spp. fed on low microfilaremic volunteers. The Mp419 LAMP assay infection rate was 0.2% for C. milnei and 0.04% for C. grahamii, while three other species were LAMP-negative. The sensitivity, species specificity, rapidity and ease of its use of these filarial LAMP assays, and validation of their performance in the field support use as alternatives to microscopy as diagnostic and surveillance tools in global health programs aimed to eliminate onchocerciasis.
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Affiliation(s)
- Glory Ngongeh Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Ngong Innocentia
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Department of Biomedical Science, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Franck Nietcho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Relindis Ekanya
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Chi Anizette Kien
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Rene Ebai
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Benjamin Lenz
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jerome Fru Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Zhiru Li
- New England Biolabs, Ipswich, MA, United States
| | - Marc P. Hübner
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, Bonn, Germany
| | | | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
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24
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Ateutchia Ngouanet S, Wanji S, Yadouleton A, Demanou M, Djouaka R, Nanfack-Minkeu F. Factors enhancing the transmission of mosquito-borne arboviruses in Africa. Virusdisease 2022; 33:477-488. [PMID: 36278029 PMCID: PMC9579656 DOI: 10.1007/s13337-022-00795-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/19/2022] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sandra Ateutchia Ngouanet
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin
- Department Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. BOX 63, Buea, Cameroon
| | - Samuel Wanji
- Department Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. BOX 63, Buea, Cameroon
| | - Anges Yadouleton
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin
| | - Maurice Demanou
- Regional Yellow Fever Laboratory Coordinator World Health Organization, Inter-Country Support Team West Africa, 03 P.O. Box 7019, Ouagadougou 03, Burkina Faso
| | - Rousseau Djouaka
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin
| | - Ferdinand Nanfack-Minkeu
- International Institute of Tropical Agriculture (IITA), 08 Tri-Postal, P.O. Box 0932, Cotonou, Benin
- Department of Biology, The College of Wooster, Wooster, OH USA
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25
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Ekanya R, Obie ED, Hamill L, Thorogood S, Abong RA, Njouendou AJ, Amuam A, Ndzeshang BL, Nkimbeng DA, Cho JF, Esum ME, Enyong P, Turner JD, Taylor MJ, Wanji S. The preparatory phase for ground larviciding implementation for chocerciasis control in the Meme River Basin in South West Cameroon: the COUNTDOWN Consortium alternative strategy implementation trial. Parasit Vectors 2022; 15:219. [PMID: 35729597 PMCID: PMC9210632 DOI: 10.1186/s13071-022-05300-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Onchocerciasis control using ivermectin alone has been achieved in some endemic savannah zones of Africa. In the forest regions, the co-endemicity with Loa loa has led to severe adverse events (SAEs) resulting in poor adherence of community members to ivermectin mass drug administration (MDA). This may jeopardize achieving the interruption of transmission of onchocerciasis. Therefore, to accelerate the elimination of onchocerciasis in L. loa co-endemic zones, alternative treatment strategies (ATS) including ground larviciding may be necessary. This study aimed at identifying Simulium breeding sites, cytospecies, transmission profile, susceptibility of Simulium larvae to insecticide (temephos) and identification of some non-target aquatic fauna prior to the implementation of the COUNTDOWN consortium ground larviciding alternative strategy in the Meme River Basin in South West Cameroon. METHODS A topographic map and entomological survey were used to determine breeding sites. Larvae and adults were identified using standard identification keys. Susceptibility tests were carried out on collected larvae by exposing them to decreasing concentrations of temephos and assessing survival rates while the cytospecies were identified using cytotaxonomy. Various entomological indicators were assessed from dissected flies. Fishing was used as proxy to traps to assess some aquatic fauna at different sites. RESULTS Twenty-two breeding sites were prospected in the Meme River Basin with eight productive for larvae. A concentration of 0.5-0.1 mg/l temephos induced 100% larval mortality. As the concentration of temephos decreased from 0.05 to 0.0025 mg/l, mortality of larvae also decreased from 98.7 to 12%. Nine cytospecies were observed in the Meme River Basin; 13,633 flies were collected and 4033 dissected. A total of 1455 flies were parous (36.1%), 224 flies were infected (5.5%), and 64 were infective (1.6%). Aquatic fauna observed included Cyprinus spp., Clarias spp., crabs, tadpoles, beetles and larvae of damsel fly. CONCLUSIONS Onchocerciasis is being actively transmitted within the Meme River Basin. Simulium larvae are susceptible to temephos, and nine cytospecies are present. Non-target fauna observed included fishes, frogs, crabs and insects. Besides treatment with ivermectin, vector control through ground larviciding may be a complementary strategy to accelerate onchocerciasis elimination in the study area.
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Affiliation(s)
- Relindis Ekanya
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Elisabeth Dibando Obie
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Louise Hamill
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Sophie Thorogood
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Raphael Awah Abong
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Abdel Jelil Njouendou
- COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon.,COUNTDOWN, Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Andrew Amuam
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Bertrand Lontum Ndzeshang
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Desmond Akumtoh Nkimbeng
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Jerome Fru Cho
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Mathias Eyong Esum
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Peter Enyong
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Joseph D Turner
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Mark J Taylor
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Samuel Wanji
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon. .,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon.
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26
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Sonhafouo-Chiana N, Nkahe LD, Kopya E, Awono-Ambene PH, Wanji S, Wondji CS, Antonio-Nkondjio C. Rapid evolution of insecticide resistance and patterns of pesticides usage in agriculture in the city of Yaoundé, Cameroon. Parasit Vectors 2022; 15:186. [PMID: 35655243 PMCID: PMC9164381 DOI: 10.1186/s13071-022-05321-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/11/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The practice of agriculture in urban settings contributes to the rapid expansion of insecticide resistance in malaria vectors. However, there is still not enough information on pesticide usage in most urban settings. The present study aims to assess the evolution of Anopheles gambiae (s.l.) population susceptibility to insecticides and patterns of pesticide usage in agriculture in the city of Yaoundé, Cameroon. METHODS WHO susceptibility tests and synergist PBO bioassays were conducted on adult An. gambiae (s.l.) mosquitoes aged 3 to 5 days emerging from larvae collected from the field. Seven insecticides (deltamethrin, permethrin, DDT, bendiocarb, propoxur, fenitrothion and malathion) were evaluated. The presence of target site mutation conferring knockdown (kdr) resistance was investigated using TaqMan assay, and mosquito species were identified using SINE-PCR. Surveys on 81 retailers and 232 farmers were conducted to assess general knowledge and practices regarding agricultural pesticide usage. RESULTS High resistance intensity to pyrethroids was observed with a high frequency of the kdr allele 1014F and low frequency of the kdr 1014S allele. The level of susceptibility of An. gambiae (s.l.) to pyrethroids and carbamates was found to decrease with time (from > 34% in 2017 to < 23% in 2019 for deltamethrin and permethrin and from 97% in 2017 to < 86% in 2019 for bendiocarb). Both An. gambiae (s.s.) and An. coluzzii were recorded. Over 150 pesticides and fertilizers were sold by retailers for agricultural purposes in the city of Yaoundé. Most farmers do not respect safety practices. Poor practices including extensive and inappropriate application of pesticides as well as poor management of perished pesticides and empty pesticide containers were also documented. CONCLUSIONS The study indicated rapid evolution of insecticide resistance and uncontrolled usage of pesticides by farmers in agriculture. There is an urgent need to address these gaps to improve the management of insecticide resistance.
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Affiliation(s)
- Nadège Sonhafouo-Chiana
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Leslie Diane Nkahe
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Edmond Kopya
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Parfait Herman Awono-Ambene
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Charles Sinclair Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Vector Biology, Liverpool School of Tropical medicine, Pembroke Place, Liverpool, L3 5QA UK
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Vector Biology, Liverpool School of Tropical medicine, Pembroke Place, Liverpool, L3 5QA UK
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27
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Nkemngo FN, Mugenzi LMJ, Tchouakui M, Nguiffo-Nguete D, Wondji MJ, Mbakam B, Tchoupo M, Ndo C, Wanji S, Wondji CS. Xeno-monitoring of molecular drivers of artemisinin and partner drug resistance in P. falciparum populations in malaria vectors across Cameroon. Gene 2022; 821:146339. [PMID: 35183684 PMCID: PMC8942117 DOI: 10.1016/j.gene.2022.146339] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 01/29/2023]
Abstract
High Plasmodium infection rate in the major Anopheles vectors across Cameroon. Emerging signal of the R575I polymorphism in the k13 propeller domain backbone. Dominance of the N86F184mdr1 variants in natural P. falciparum populations. Low k13 and mdr1 genetic diversity in P. falciparum-infected mosquitoes.
Background Monitoring of drug resistance in Plasmodium populations is crucial for malaria control. This has primarily been performed in humans and rarely in mosquitoes where parasites genetic recombination occurs. Here, we characterized the Plasmodium spp populations in wild Anopheles vectors by analyzing the genetic diversity of the P. falciparum kelch13 and mdr1 gene fragments implicated in artemisinin and partner drug resistance across Cameroon in three major malaria vectors. Methods Anopheles mosquitoes were collected across nine localities in Cameroon and dissected into the head/thorax (H/T) and abdomen (Abd) after species identification. A TaqMan assay was performed to detect Plasmodium infection. Fragments of the Kelch 13 and mdr1 genes were amplified in P. falciparum positive samples and directly sequenced to assess their drug resistance polymorphisms and genetic diversity profile. Results The study revealed a high Plasmodium infection rate in the major Anopheles vectors across Cameroon. Notably, An. funestus vector recorded the highest sporozoite (8.0%) and oocyst (14.4%) infection rates. A high P. falciparum sporozoite rate (80.08%) alongside epidemiological signatures of significant P. malariae (15.9%) circulation were recorded in these vectors. Low genetic diversity with six (A578S, R575I, G450R, L663L, G453D, N458D) and eight (H53H, V62L, V77E, N86Y, G102G, L132I, H143H, Y184F) point mutations were observed in the k13 and mdr1 backbones respectively. Remarkably, the R575I (4.4%) k13 and Y184F (64.2%) mdr1 mutations were the predominant variants in the P. falciparum populations. Conclusion The emerging signal of the R575I polymorphism in the Pfk13 propeller backbone entails the regular surveillance of molecular markers to inform evidence-based policy decisions. Moreover, the high frequency of the 86N184F allele highlights concerns on the plausible decline in efficacy of artemisinin-combination therapies (ACTs); further implying that parasite genotyping from mosquitoes can provide a more relevant scale for quantifying resistance epidemiology in the field.
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Affiliation(s)
- Francis N Nkemngo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Magellan Tchouakui
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Daniel Nguiffo-Nguete
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Bertrand Mbakam
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon.
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon; Research Foundation in Tropical Diseases and Environment, Buea, Cameroon.
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
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Pionnier N, Furlong-Silva J, Colombo SAP, Marriott AE, Chunda VC, Ndzeshang BL, Sjoberg H, Archer J, Steven A, Wanji S, Taylor MJ, Turner JD. NKp46 + natural killer cells develop an activated/memory-like phenotype and contribute to innate immunity against experimental filarial infection. Front Immunol 2022; 13:969340. [PMID: 36238293 PMCID: PMC9551455 DOI: 10.3389/fimmu.2022.969340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 09/05/2022] [Indexed: 11/13/2022] Open
Abstract
Lymphatic filariasis and onchocerciasis are major neglected tropical diseases affecting over 90 million people worldwide with painful and profoundly disfiguring pathologies (such as lymphoedema or blindness). Type 2 inflammation is a hallmark of filarial nematode tissue infection and is implicated both in eosinophil dependent immunity and lymphatic or ocular immunopathologies. Type-2 innate lymphoid cells (ILC2) are known to play an important role in the initiation of type 2 inflammation in helminth infection. We therefore tracked comparative IL-12Rβ2+ ILC1, ST2+ ILC2 and NKp46+ natural killer (NK) innate lymphoid cell population expansions during Brugia malayi experimental peritoneal filarial infections using either immunocompetent or immunodeficient mice. In immunocompetent BALB/c animals, NKp46+ NK cells rapidly expanded representing over 90% of the ILC population in the first week of infection, whereas, surprisingly, ST2+ ILC2 failed to expand. NKp46+ NK cell expansions were confirmed in RAG2 deficient mice lacking adaptive immunity. Ablation of the NKp46+ NK cell compartment in RAG2 common gamma chain (gc) mice led to increased susceptibility to chronic adult B. malayi infection. This data was recapitulated using an Onchocerca ochengi male worm peritoneal implant model. When NKp46+ NK cells were depleted in RAG2 deficient mice using anti-NKp46 or asialo GM1 antibody injections over the first five weeks of B. malayi infection, susceptibility to adult B. malayi infection was significantly increased by 2-3 fold with concomitant impairment in eosinophil or neutrophil recruitments. Finally, we demonstrate that in RAG2 deficient mice, drug clearance of a primary adult B. malayi infection followed by challenge infection leads to resistance against early larval B. malayi establishment. This innate resistance is associated with bolstered NK and eosinophils whereby NKp46+ NK cells express markers of memory-like/enhanced activation (increased expression of interferon gamma and Ly6C). Our data promotes a novel functional role for NKp46+ NK cells in immunoprotection against experimental primary and secondary filarial infection which can proceed in the absence of adaptive immune regulation.
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Affiliation(s)
- Nicolas Pionnier
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Centre for Bioscience, John Dalton Building, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, United Kingdom
| | - Julio Furlong-Silva
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Stefano A P Colombo
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Amy E Marriott
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Valerine C Chunda
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Bertrand L Ndzeshang
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Hanna Sjoberg
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - John Archer
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Andrew Steven
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Samuel Wanji
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Mark J Taylor
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Joseph D Turner
- Centre for Drugs and Diagnostics, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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29
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Wiszniewsky A, Layland LE, Arndts K, Wadephul LM, Tamadaho RSE, Borrero-Wolff D, Chunda VC, Kien CA, Hoerauf A, Wanji S, Ritter M. Adoptive Transfer of Immune Cells Into RAG2IL-2Rγ-Deficient Mice During Litomosoides sigmodontis Infection: A Novel Approach to Investigate Filarial-Specific Immune Responses. Front Immunol 2021; 12:777860. [PMID: 34868049 PMCID: PMC8636703 DOI: 10.3389/fimmu.2021.777860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/25/2021] [Indexed: 12/03/2022] Open
Abstract
Despite long-term mass drug administration programmes, approximately 220 million people are still infected with filariae in endemic regions. Several research studies have characterized host immune responses but a major obstacle for research on human filariae has been the inability to obtain adult worms which in turn has hindered analysis on infection kinetics and immune signalling. Although the Litomosoides sigmodontis filarial mouse model is well-established, the complex immunological mechanisms associated with filarial control and disease progression remain unclear and translation to human infections is difficult, especially since human filarial infections in rodents are limited. To overcome these obstacles, we performed adoptive immune cell transfer experiments into RAG2IL-2Rγ-deficient C57BL/6 mice. These mice lack T, B and natural killer cells and are susceptible to infection with the human filaria Loa loa. In this study, we revealed a long-term release of L. sigmodontis offspring (microfilariae) in RAG2IL-2Rγ-deficient C57BL/6 mice, which contrasts to C57BL/6 mice which normally eliminate the parasites before patency. We further showed that CD4+ T cells isolated from acute L. sigmodontis-infected C57BL/6 donor mice or mice that already cleared the infection were able to eliminate the parasite and prevent inflammation at the site of infection. In addition, the clearance of the parasites was associated with Th17 polarization of the CD4+ T cells. Consequently, adoptive transfer of immune cell subsets into RAG2IL-2Rγ-deficient C57BL/6 mice will provide an optimal platform to decipher characteristics of distinct immune cells that are crucial for the immunity against rodent and human filarial infections and moreover, might be useful for preclinical research, especially about the efficacy of macrofilaricidal drugs.
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Affiliation(s)
- Anna Wiszniewsky
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Laura E Layland
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany.,German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Kathrin Arndts
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Lisa M Wadephul
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Ruth S E Tamadaho
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Dennis Borrero-Wolff
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Valerine C Chunda
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Chi Anizette Kien
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany.,German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.,German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, Bonn, Germany
| | - Samuel Wanji
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
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30
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Wanji S, Chunda VC, Fombad FF, Jélil Njouendou A, Gandjui NVT, Ritter M, Enyong PA, Mackenzie C, Taylor MJ, Hoerauf A, Turner JD. Advances in preclinical platforms of Loa loa for filarial neglected tropical disease drug and diagnostics research. Front Trop Dis 2021; 2:778724. [PMID: 38654889 PMCID: PMC7615857 DOI: 10.3389/fitd.2021.778724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
The tropical disease, loiasis, caused by the filarial parasite, Loa, has gained prominence in global public health as a cause of excess mortality and a barrier to the elimination of the related prioritized neglected tropical diseases (NTDs), lymphatic filariasis and onchocerciasis, within Central Africa. There are no effective drug cures or vaccines available to treat loiasis safely. Here we review recent advances in loiasis preclinical platform technologies, including novel in vitro culturing systems, animal models and innovations in experimental infections of the L. loa vector, Chrysops, that have facilitated access to all L. loa filarial life-cycle stages. We detail applications of these new model systems in anti-filarial drug screening, diagnostic development, immunology, and pathophysiology research. Finally, we provide an overview of how loiasis preclinical platforms may be further utilized in translational medicine applications to support the development of much needed new interventions against filarial NTDs.
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Affiliation(s)
- Samuel Wanji
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Valerine Chawa Chunda
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Abdel Jélil Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Narcisse Victor T. Gandjui
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Peter A. Enyong
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Charles Mackenzie
- Neglected Tropical Diseases Support Center l The Task Force for Global Health, 325 Swanton Way, Decatur, Atlanta, Georgia, United States of America
| | - Mark J Taylor
- Centre for Drugs and Diagnostics Research and Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), Bonn-Cologne partner site, Bonn, Germany
| | - Joseph D Turner
- Centre for Drugs and Diagnostics Research and Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Akumtoh DN, Njouendou AJ, Metuge HM, Sjoberg HT, Pionnier NP, Chunda VC, Gandjui NVT, Ndzeshang LB, Fombad FF, Abong RA, Enyong PA, Fru-Cho J, Esum ME, Ritter M, Taylor MJ, Turner JD, Wanji S. Onchocerca ochengi male worms implanted in SCID mice and Gerbil: Relationship between microfilaridermia status of cows, nodular worm viability and fertility and worm survival in the rodents. Exp Parasitol 2021; 229:108143. [PMID: 34437906 PMCID: PMC8518880 DOI: 10.1016/j.exppara.2021.108143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 05/06/2021] [Accepted: 08/16/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Current treatment options for onchocerciasis are sub-optimal, prompting research and development of a safe cure (macrofilaricide). Onchocerca ochengi, a parasite of cattle, is used as a close surrogate for the human parasite O. volvulus in a murine model for pre-clinical screening of macrofilaricides. Skin from naturally infected cattle have been used in previous studies as a reliable source of parasite material. However, there is limited knowledge on how source-related factors such as the microfilaridermia status of the cattle, the nodule load and nodular worm viability may affect survival of male O. ochengi worms implanted in the rodent hosts. Such relationships were investigated in this study. METHODS Dermal tissue and nodules were obtained from Gudali cattle, dissected and cultured to obtain migrating microfilariae (mf) and male worms. Emerged male worms were implanted into SCID mice and Gerbils (Meriones unguiculatus) and recovery rates were determined upon 42 days post implantation. Finally, nodules were processed for histology and embryogram analyses to assess the nodular worm viability and fertility, respectively. RESULTS Of the 69 cattle sampled, 24 (34.8%) were mf+ and 45 (65.2%) were mf-. The mean nodule loads were 180.5 ± 117.7 (mf+) and 110.6 ± 102.7 (mf-) (p = 0.0186). The mean male worm harvest from nodules were 76.8 ± 120.3 and 47.2 ± 33.4 (p = 0.2488) for mf+ and mf- cattle, respectively. The number of male worms per 100 nodules were 57/100 and 46/100 nodules for mf+ and mf- cows, respectively. Female worms from nodules of mf- cows had higher counts of both normal and abnormal embryos with higher proportions of dead nodular worms evinced by histology compared to those from mf+ cows. A total of 651 worms were implanted into mice and gerbils, out of which 129 (19.81%) were recovered. Logistic regression analysis indicated that the microfilaridermia status of the cattle (presence of mf) (OR = 4.3319; P = 0.001) is the single most important predictor of the success of male worm recovery after implantation into rodents. CONCLUSION Microfilaridermic cattle provide a promising source of adult O. ochengi. Male worms from this group of cattle have a better success rate of survival in a murine implant model. Nevertheless, in the programmatic point of view, amicrofilaridermic Gudali cattle would still constitute an important source of O. ochengi male worms with relatively good viability after implantation into rodents.
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Affiliation(s)
- Desmond N Akumtoh
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Abdel J Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon.
| | - Haelly M Metuge
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Hanna T Sjoberg
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nicolas P Pionnier
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Valerine C Chunda
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Narcisse Victor T Gandjui
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Lontum B Ndzeshang
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Fanny F Fombad
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon.
| | - Raphael A Abong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Peter A Enyong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Jerome Fru-Cho
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Mathias E Esum
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany; German Center for Infection Research (DZIF), Bonn - Cologne Partner Site, Bonn, Germany.
| | - Mark J Taylor
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Joseph D Turner
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
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Wanji S, Deribe K, Minich J, Debrah AY, Kalinga A, Kroidl I, Luguet A, Hoerauf A, Ritter M. Podoconiosis - From known to unknown: Obstacles to tackle. Acta Trop 2021; 219:105918. [PMID: 33839086 DOI: 10.1016/j.actatropica.2021.105918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/24/2021] [Accepted: 04/01/2021] [Indexed: 12/17/2022]
Abstract
Podoconiosis is a non-filarial and non-communicable disease leading to lymphedema of the lower limbs. Worldwide, 4 million individuals live with podoconiosis, which is accompanied by disability and painful intermittent acute inflammatory episodes that attribute to significant disability adjusted life years (DALYs). Different risk factors like contact with volcanic red clay soil, high altitude (above 1000 m), high seasonal rainfall (above 1000 mm/year) and occupation (e.g., subsistence farmer) are associated with the risk of podoconiosis. Although podoconiosis was described to be endemic in 32 countries in Africa, parts of Latin America and South East Asia, knowledge about related genetics, pathophysiology, immunology and especially the causing molecule(s) in the soil remain uncertain. Thus, podoconiosis can be considered as one of the most neglected diseases. This review provides an overview about this non-filarial related geochemical disease and aim to present perspectives and future directions that might be important for better understanding of the disease, prospect for point-of-care diagnosis, achieving protection and developing novel treatment strategies.
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Forrer A, Wanji S, Obie ED, Nji TM, Hamill L, Ozano K, Piotrowski H, Dean L, Njouendou AJ, Ekanya R, Ndongmo WPC, Fung EG, Nnamdi DB, Abong RA, Beng AA, Eyong ME, Ndzeshang BL, Nkimbeng DA, Teghen S, Suireng A, Ashu EE, Kah E, Murdoch MM, Thomson R, Theobald S, Enyong P, Turner JD, Taylor MJ. Why onchocerciasis transmission persists after 15 annual ivermectin mass drug administrations in South-West Cameroon. BMJ Glob Health 2021; 6:bmjgh-2020-003248. [PMID: 33431378 PMCID: PMC7802695 DOI: 10.1136/bmjgh-2020-003248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 11/11/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Introduction Onchocerciasis is targeted for elimination mainly with annual community-directed treatment with ivermectin (CDTI). High infection levels have been reported in South-West Cameroon, despite ≥15 years of CDTI. The aim of this study was to assess factors associated with continued onchocerciasis transmission and skin disease. Methods A large-scale cross-sectional study was conducted in 2017 in 20 communities in a loiasis-risk area in South-West Cameroon. A mixed-methods approach was used. Associations between infection levels, skin disease and adherence to CDTI were assessed using mixed regression modelling. Different community members’ perception and acceptability of the CDTI strategy was explored using semi-structured interviews. Results Onchocerciasis prevalence was 44.4% among 9456 participants. 17.5% of adults were systematic non-adherers and 5.9% participated in ≥75% of CDTI rounds. Skin disease affected 1/10 participants, including children. Increasing self-reported adherence to CDTI was associated with lower infection levels in participants aged ≥15 years but not in children. Adherence to CDTI was positively influenced by perceived health benefits, and negatively influenced by fear of adverse events linked with economic loss. Concern of lethal adverse events was a common reason for systematic non-adherence. Conclusion CDTI alone is unlikely to achieve elimination in those high transmission areas where low participation is commonly associated with the fear of adverse events, despite the current quasi absence of high-risk levels of loiasis. Such persisting historical memories and fear of ivermectin might impact adherence to CDTI also in areas with historical presence but current absence of loiasis. Because such issues are unlikely to be tackled by CDTI adaptive measures, alternative strategies are needed for onchocerciasis elimination where negative perception of ivermectin is an entrenched barrier to community participation in programmes.
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Affiliation(s)
- Armelle Forrer
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Samuel Wanji
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Elisabeth Dibando Obie
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Theobald Mue Nji
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Louise Hamill
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Kim Ozano
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Helen Piotrowski
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Laura Dean
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Abdel J Njouendou
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Relindis Ekanya
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Winston Patrick Chounna Ndongmo
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Ebua Gallus Fung
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Dum-Buo Nnamdi
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Raphael A Abong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Amuam Andrew Beng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Mathias Esum Eyong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Bertrand L Ndzeshang
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Desmond Akumtoh Nkimbeng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Samuel Teghen
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Anicetus Suireng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Ernerstine Ebot Ashu
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Emmanuel Kah
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Michele M Murdoch
- Watford General Hospital, West Herts Hospitals NHS Trust, Watford, UK
| | - Rachael Thomson
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Sally Theobald
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Peter Enyong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Joseph D Turner
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Mark J Taylor
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
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Ndzeshang BL, Mbiakop RT, Nchanji GT, Kien CA, Amambo GN, Abong RA, Yuyun T, Beng AA, Bonekeh J, Ritter M, Esum ME, Cho JF, Njouendou AJ, Ndifor IN, Deribe K, Fombad FF, Enyong P, Klarmann-Schulz U, Hoerauf A, Wanji S. Clinical, haematological and biochemical profiling of podoconiosis lymphoedema patients prior to their involvement in a clinical trial in the Northwest Region of Cameroon. Trans R Soc Trop Med Hyg 2021; 114:954-961. [PMID: 33258944 PMCID: PMC7738657 DOI: 10.1093/trstmh/traa146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/03/2020] [Accepted: 11/09/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Prior to carrying out clinical trials, it is important to assess the health status of the study participants to be able to interpret subsequent changes that may be related to the effects of the treatments during the follow-up of patients. This study presents the clinical, haematological and biochemical profiles of podoconiosis patients prior to their involvement in the PodoLEDoxy clinical trial. METHODS All lower limb lymphoedema patients visiting the centre were screened and a podoconiosis diagnosis was based on clinical manifestation and detailed medical history. Patients who satisfied the eligibility criteria were enrolled in the study and their demographic data, vital signs and medical history were collected followed by biochemical and haematological examinations. RESULTS Of the 222 participants enrolled in the study, 55.4% and 41.4% had either stage 3 or 2 podoconiosis as their highest stages, respectively. On physical examination, gastritis (46%) and poor vision (2.7%) were the most prevalent health issues identified. The majority of haematological and biochemical values were within the normal range except for mean platelet volume (47.7%), plateletcrit (58.1%), platelet distribution width (66.2%), mean corpuscular volume (67.6%) and red cell distribution width-standard deviation (79.3%), where >40% of the study participants had values out of the normal. CONCLUSION The clinical, haematological and biochemical profiles of the study participants were largely within the normal range except for certain haematological parameters that might be worth investigating.
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Affiliation(s)
- Bertrand Lontum Ndzeshang
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Randy Tchachoua Mbiakop
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Gordon Takop Nchanji
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Chi Anizette Kien
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Glory Ngongeh Amambo
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Raphael Awah Abong
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Timothy Yuyun
- Regional Hospital Bamenda, P.O. Box 818, Bamenda Cameroon
| | - Amuam Andrew Beng
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - John Bonekeh
- Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Mathias Eyong Esum
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Jerome Fru Cho
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | | | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, BN1 9PX, UK.,School of Public Health, Addis Ababa University, Ethiopia
| | - Fanny Fri Fombad
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Peter Enyong
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany.,German Center for Infection Research (DZIF), partner-site Bonn-Cologne, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany.,German Center for Infection Research (DZIF), partner-site Bonn-Cologne, Germany
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon
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Nji TM, Piotrowski H, Dum-Buo N, Fung EG, Dean L, Theobald S, Thomson R, Wanji S, Ozano K. Eliminating onchocerciasis within the Meme River Basin of Cameroon: A social-ecological approach to understanding everyday realities and health systems. PLoS Negl Trop Dis 2021; 15:e0009433. [PMID: 34077416 PMCID: PMC8202923 DOI: 10.1371/journal.pntd.0009433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 06/14/2021] [Accepted: 05/02/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Onchocerciasis affects some of the world's most marginalized people, perpetuating poverty and inequalities. Mass Drug Administration (MDA) with Ivermectin has taken place within the Meme River basin region in Cameroon for over 15 years. Despite this, onchocerciasis is still prevalent in the region due to existing and emerging contextual challenges. Using a social-ecological approach we explore the everyday realities of communities, highlighting the challenges and potential solutions that could support Neglected Tropical Disease (NTD) programmes when transitioning from control to elimination of onchocerciasis in this highly endemic area and other similar communities. METHODOLOGY/PRINCIPAL FINDING In-depth interviews (71) with community members and Community Drug Distributors (CDDs) were conducted to understand current knowledge, attitudes, and behaviours in relation to transmission, prevention and treatment of onchocerciasis. Through application of the social-ecological model, four key themes were identified: 1. Contextual factors on health promotion interventions (Onchocerciasis history and understanding of the disease, prevention and mitigation strategies and MDA experience); 2. Social determinants (poverty and livelihoods, economic and social impacts on CDD volunteers and stigma); 3. Environmental determinants (exposure, housing, occupation and poverty); and 4. health seeking pathways and decision making for treatment (access, cost and preferable treatment routes). We discuss these core and cross cutting themes (gender differences and community participation/ownership) in relation to intersectoral collaboration, gender equity and health systems support, making recommendations for NTD programmes within the context of integrated and interdisciplinary approaches. These include the need for; intersectional and gender analysis at the local level, addressing environmental dimensions of onchocerciasis through integrated and regular health promotion, vector control strategies and access to safe water sources; reflection and action that embeds responses to social and economic barriers to MDA; integrated case detection and management that is responsive to onchocerciasis symptoms and related stigma and a fair and just support network for CDDs. CONCLUSION/SIGNIFICANCE NTD programmes need to respond to diverse community circumstances and behaviours. Communities are not a homogeneous risk group and treating them in this way will delay elimination. A deeper understanding of individual needs and their capacity to seek prevention and treatment must be considered if onchocerciasis is to be eliminated and the remaining impacts managed.
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Affiliation(s)
- Theobald Mue Nji
- Department of Sociology and Anthropology, Faculty of Social and Management Sciences, University of Buea, Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Helen Piotrowski
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nnamdi Dum-Buo
- Department of Sociology and Anthropology, Faculty of Social and Management Sciences, University of Buea, Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Ebua Gallus Fung
- Department of Sociology and Anthropology, Faculty of Social and Management Sciences, University of Buea, Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Laura Dean
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sally Theobald
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rachael Thomson
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
| | - Kim Ozano
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Badia-Rius X, Betts H, Wanji S, Molyneux D, Taylor MJ, Kelly-Hope LA. Environmental Factors Associated With Loa loa Microfilaria Prevalence and Intensity in Diverse Bioecological Zones of Cameroon. Front Trop Dis 2021. [DOI: 10.3389/fitd.2021.668641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Loiasis (African Eye Worm) is a filarial infection caused by Loa loa and transmitted by Chrysops vectors, which are confined to the tropical rainforests of Central and West Africa. Loiasis is a major impediment to control and elimination programmes that use the drug ivermectin due to the risk of serious adverse events. There is an urgent need to better refine and map high-risk communities. This study aimed to quantify and predict environmental factors associated with loiasis across five bioecological zones in Cameroon. The L. loa microfilaria (mf) prevalence (%) and intensity (mf number/ml) data from 42 villages within an Equatorial Rainforest and Savannah region were examined in relation to climate, topographic and forest-related data derived from satellite remote sensing sources. Differences between zones and regions were examined using nonparametric tests, and the relationship between L. loa mf prevalence, mf intensity, and the environmental factors using polynomial regression models. Overall, the L. loa mf prevalence was 11.6%, L. loa intensity 927.4 mf/ml, mean annual temperature 23.7°C, annual precipitation 2143.2 mm, elevation 790 m, tree canopy cover 46.7%, and canopy height 19.3m. Significant differences between the Equatorial Rainforest and Savannah region were found. Within the Equatorial Rainforest region, no significant differences were found. However, within the Savannah region, significant differences between the three bioecological zones were found, and the regression models indicated that tree canopy cover and elevation were significant predictors, explaining 85.1% of the L. loa mf prevalence (adjusted R2 = 0.851; p<0.001) and tree cover alone was significant, explaining 58.1% of the mf intensity (adjusted R2 = 0.581; p<0.001). The study highlights that environmental analysis can help delineate risk at different geographical scales, which may be practical for developing larger scale operational plans for mapping and implementing safe effective interventions.
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Gandjui NVT, Njouendou AJ, Gemeg EN, Fombad FF, Ritter M, Kien CA, Chunda VC, Fru J, Esum ME, Hübner MP, Enyong PA, Hoerauf A, Wanji S. Establishment of an in vitro culture system to study the developmental biology of Onchocerca volvulus with implications for anti-Onchocerca drug discovery and screening. PLoS Negl Trop Dis 2021; 15:e0008513. [PMID: 33561123 PMCID: PMC7899360 DOI: 10.1371/journal.pntd.0008513] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 02/22/2021] [Accepted: 01/13/2021] [Indexed: 11/21/2022] Open
Abstract
Background Infections with Onchocerca volvulus nematodes remain a threat in Sub-Saharan Africa after three decades of ivermectin mass drug administration. Despite this effort, there is still an urgent need for understanding the parasite biology especially the mating behaviour and nodule formation as well as the development of more potent drugs that can clear the developmental (L3, L4, L5) and adult stages of the parasite and inhibit parasite reproduction and behaviour. Methodology/Principal findings Prior to culture, freshly harvested O. volvulus L3 larvae from dissected Simulium damnosum flies were purified by centrifugation using a 30% Percoll solution to eliminate fly tissue debris and contaminants. Parasites were cultured in both cell-free and cell-based co-culture systems and monitored daily by microscopic visual inspection. Exhausted culture medium was replenished every 2–3 days. The cell-free culture system (DMEM supplemented with 10% NCS) supported the viability and motility of O. volvulus larvae for up to 84 days, while the co-culture system (DMEM supplemented with 10% FBS and seeded on LLC-MK2 feeder cells) extended worm survival for up to 315 days. Co-culture systems alone promoted two consecutive parasite moults (L3 to L4 and L4 to L5) with highest moulting rates (69.2±30%) observed in DMEM supplemented with 10% FBS and seeded on LLC-MK2 feeder cells, while no moult was observed in DMEM supplemented with 10% NCS and seeded on LEC feeder cells. In DMEM supplemented with 10% FBS and seeded on LLC-MK2 feeder cells, O. volvulus adult male worms attached to the vulva region of adult female worms and may have mated in vitro. Apparent early initiation of nodulogenesis was observed in both DMEM supplemented with 10% FBS and seeded on LLC-MK2 and DMEM supplemented with 10% NCS and seeded on LLC-MK2 systems. Conclusions/Significance The present study describes an in vitro system in which O. volvulus L3 larvae can be maintained in culture leading to the development of adult stages. Thus, this in vitro system may provide a platform to investigate mating behaviour and early stage of nodulogenesis of O. volvulus adult worms that can be used as additional targets for macrofilaricidal drug screening. River blindness affects people living in mostly remote and underserved rural communities in some of the poorest areas of the world. Although significant efforts have been achieved towards the reduction of disease morbidity, onchocerciasis still affects millions of people in Sub-Saharan Africa. The current control strategy is the annual mass administration of ivermectin which has accumulated several drawbacks over time, especially the action of the drug is solely microfilaricidal, very long treatment period (15–17 years) and reports of ivermectin losing its efficacy; thus, raising the urgent need for new adulticidal compounds. Our study has established an in vitro platform capable of supporting the growth and development of Onchocerca volvulus for up to 315 days, enabling the observation of parasite developmental processes: moulting (from the infective L3 stage to adults), increase in morphometry, the attachment of adult male and female worms and the potential initiation of nodulogenesis. Moreover, the platform might provide more insight into O. volvulus adult worms behavioural pattern in vitro. Also, our findings provide more avenues for mass production of different parasite stages, the investigation of parasite developmental biology and the identification of targets for drug discovery against different developmental stages of this filarial parasite within 315 days.
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Affiliation(s)
- Narcisse V. T. Gandjui
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Abdel J. Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Eric N. Gemeg
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Fanny F. Fombad
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Chi A. Kien
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Valerine C. Chunda
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Jerome Fru
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Mathias E. Esum
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Marc P. Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), Bonn-Cologne partner site, Bonn, Germany
| | - Peter A. Enyong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), Bonn-Cologne partner site, Bonn, Germany
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- * E-mail:
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Abong RA, Amambo GN, Hamid AA, Enow BA, Beng AA, Nietcho FN, Nji TM, Njouendou AJ, Ritter M, Esum ME, Deribe K, Cho JF, Fombad FF, Enyong PI, Poole C, Pfarr K, Hoerauf A, Carlow C, Wanji S. The Mbam drainage system and onchocerciasis transmission post ivermectin mass drug administration (MDA) campaign, Cameroon. PLoS Negl Trop Dis 2021; 15:e0008926. [PMID: 33465080 PMCID: PMC7815102 DOI: 10.1371/journal.pntd.0008926] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 10/27/2020] [Indexed: 11/19/2022] Open
Abstract
Background The impact of large scale Mass Drug Adminstration (MDA) of ivermectin on active onchocerciasis transmission by Simulium damnosum, which transmits the parasite O. volvulus is of great importance for onchocerciasis control programmes. We investigated in the Mbam river system area, the impact of MDA of ivermectin on entomological indices and also verify if there are river system factors that could have favoured the transmission of onchocerciasis in this area and contribute to the persistence of disease. We compared three independent techniques to detect Onchocerca larvae in blackflies and also analyzed the river system within 9 months post-MDA of ivermectin. Method Simulium flies were captured before and after 1, 3, 6 and 9months of ivermectin-MDA. The biting rate was determined and 41% of the flies dissected while the rest were grouped into pools of 100 flies for DNA extraction. The extracted DNA was then subjected to O-150 LAMP and real-time PCR for the detection of infection by Onchocerca species using pool screening. The river system was analysed and the water discharge compared between rainy and dry seasons. Principal findings We used human landing collection method (previously called human bait) to collect 22,274 adult female Simulium flies from Mbam River System. Of this number, 9,134 were dissected while 129 pools constituted for molecular screening. Overall biting and parous rates of 1113 flies/man/day and 24.7%, respectively, were observed. All diagnostic techniques detected similar rates of O. volvulus infection (P = 0.9252) and infectivity (P = 0.4825) at all monitoring time points. Onchocerca ochengi larvae were only detected in 2 of the 129 pools. Analysis of the river drainage revealed two hydroelectric dams constructed on the tributaries of the Mbam river were the key contributing factor to the high-water discharge during both rainy and dry seasons. Conclusion Results from fly dissection (Microscopy), real-time PCR and LAMP revealed the same trends pre- and post-MDA. The infection rate with animal Onchocerca sp was exceptionally low. The dense river system generate important breeding sites that govern the abundance of Simulium during both dry and rainy seasons. The presence of parasite strains that respond sub-optimally to an approved drug, favourable breeding sites for the vector and infected individual in an area, will surely provide conditions for continuous and persistent transmission of a disease despite a long-term control intervention. We investigated the impact of ivermectin on entomological indices within 9 months following a large-scale MDA in the Mbam river drainage. The river system factors that could have favoured abundance vector breeding and contribute to the persistence of disease transmission were also examined within the study period. We observed vector abundance and high entomological indices throughout the study period following ivermectin MDA. We also observed high water discharge along the main river of the drainage basin in both the rainy and dry seasons and this is due to the presence of two dams constructed upstream at Bamendjing and Mape to regularize the course of river Sanaga in view of generating hydroelectric power at Edea. Factors favouring continuous and persistent disease transmission are present in this drainage basin despite over 20 years of annual IVM-MDA. There is need for alternative control strategy in order to accelerate the fight against onchocerciasis in the area.
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Affiliation(s)
- Raphael Awah Abong
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Glory Ngongeh Amambo
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Ali Ahamat Hamid
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Belinda Agbor Enow
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Franck Noel Nietcho
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Theobald Mue Nji
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
- Department of Sociology and Anthropology, University of Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Department of Biomedical science, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Mathias Eyong Esum
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jerome Fru Cho
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Catherine Poole
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Kenneth Pfarr
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Clotilde Carlow
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Samuel Wanji
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
- * E-mail:
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Abong RA, Amambo GN, Chounna Ndongmo PW, Njouendou AJ, Ritter M, Beng AA, Esum ME, Deribe K, Fru-Cho J, Fombad FF, Nji TM, Enyong PI, Poole CB, Pfarr K, Hoerauf A, Carlow CKS, Wanji S. Correction to: Differential susceptibility of Onchocerca volvulus microfilaria to ivermectin in two areas of contrasting history of mass drug administration in Cameroon: relevance of microscopy and molecular techniques for the monitoring of skin microfilarial repopulation within six months of direct observed treatment. BMC Infect Dis 2021; 21:81. [PMID: 33461481 PMCID: PMC7814557 DOI: 10.1186/s12879-021-05797-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Glory N Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Patrick W Chounna Ndongmo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Department of Biomedical science, Faculty of Health Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, BN1 9PX, UK.,School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jerome Fru-Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Fanny F Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Theobald Mue Nji
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | | | - Kenneth Pfarr
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | | | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon.
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Amambo GN, Abong RA, Fombad FF, Njouendou AJ, Nietcho F, Beng AA, Manuel R, Esum ME, Deribe K, Cho JF, Enyong PI, Poole C, Hoerauf A, Carlow C, Wanji S. Validation of loop-mediated isothermal amplification for the detection of Loa loa infection in Chrysops spp in experimental and natural field conditions. Parasit Vectors 2021; 14:19. [PMID: 33407819 PMCID: PMC7788981 DOI: 10.1186/s13071-020-04506-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The mass drug administration of ivermectin for onchocerciasis control has contributed to a significant drop in Loa loa microfilaria loads in humans that has, in turn, led to reduction of infection levels in Chrysops vectors. Accurate parasite detection is essential for assessing loiasis transmission as it provides a potential alternative or indirect strategy for addressing the problem of co-endemic loiasis and lymphatic filariasis through the Onchocerciasis Elimination Programme and it further reflects the true magnitude of the loiasis problem as excess human mortality has been reported to be associated with the disease. Although microscopy is the gold standard for detecting the infection, the sensitivity of this method is compromised when the intensity of infection is low. The loop-mediated isothermal amplification (LAMP) assay of parasite DNA is an alternative method for detecting infection which offers operational simplicity, rapidity and versatility of visual readout options. The aim of this study was to validate the Loa loa LAMP assay for the detection of infected Chrysops spp. under experimental and natural field conditions. METHODS Two sets of 18 flies were fed on volunteers with either a low (< 10 mf/ml) or high (> 30,000mf/ml) microfilarial load. The fed flies were maintained under laboratory conditions for 14 days and then analysed using LAMP for the detection of L. loa infection. In addition, a total of 9270 flies were collected from the north-west, east, and south-west regions (SW 1 and 2) of Cameroon using sweep nets and subjected to microscopy (7841 flies) and LAMP (1291 flies plus 138 nulliparous flies) analyses. RESULTS The LAMP assay successfully detected parasites in Chrysops fed on volunteers with both low and high microfilariaemic loads. Field validation and surveillance studies revealed LAMP-based infection rates ranging from 0.5 to 31.6%, with the lowest levels in SW 2 and the highest infection rates in SW 1. The LAMP assay detected significantly higher infection rates than microscopy in four of the five study sites. CONCLUSION This study demonstrated the potential of LAMP as a simple surveillance tool. It was found to be more sensitive than microscopy for the detection of experimental and natural L. loa infections in Chrysops vectors.
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Affiliation(s)
- Glory Ngongeh Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Fanny Fri Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Department of Biomedical science, Faculty of Health Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Franck Nietcho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Ritter Manuel
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, BN1 9PX, UK
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jerome Fru Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | | | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | | | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon.
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Vinkeles Melchers NVS, Coffeng LE, Boussinesq M, Pedrique B, Pion SDS, Tekle AH, Zouré HGM, Wanji S, Remme JH, Stolk WA. Projected Number of People With Onchocerciasis-Loiasis Coinfection in Africa, 1995 to 2025. Clin Infect Dis 2021; 70:2281-2289. [PMID: 31304961 PMCID: PMC7245158 DOI: 10.1093/cid/ciz647] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/12/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Onchocerciasis elimination through mass drug administration (MDA) is hampered by coendemicity of Loa loa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and loiasis prevalence and estimated the number of coinfected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS Focusing on regions with suspected loiasis transmission in 14 countries, we overlaid precontrol maps of loiasis and onchocerciasis prevalence to calculate precontrol prevalence of coinfection by 5 km2 × 5 km2 pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted prevalence of both infections and coinfection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137 000 people were estimated to also have L. loa hypermicrofilaremia (≥20 000 L. loa mf/mL) in 1995, declining to 31 000 in 2025. In 2025, 92.8% of coinfected cases with loiasis hypermicrofilaremia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS Loiasis coinfection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31 000 coinfected people still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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Affiliation(s)
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Michel Boussinesq
- Unité Mixte Internationale 233 TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM U1175, University of Montpellier, Montpellier, France
| | - Belén Pedrique
- Research & Development Department, Drugs for Neglected Diseases initiative, and, Geneva, Switzerland
| | - Sébastien D S Pion
- Unité Mixte Internationale 233 TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM U1175, University of Montpellier, Montpellier, France
| | - Afework H Tekle
- Preventive Chemotherapy and Transmission Control Unit, Control of Neglected Tropical Diseases Department, World Health Organization, Geneva, Switzerland
| | - Honorat G M Zouré
- Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), World Health Organization, Regional Office for Africa, Cité du Djoué, Brazzaville, Republic of Congo
| | - Samuel Wanji
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, Cameroon
| | | | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands
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Cheteug G, Elanga-Ndille E, Donkeu C, Ekoko W, Oloume M, Essangui E, Nwane P, NSango SE, Etang J, Wanji S, Ayong L, Eboumbou Moukoko CE. Preliminary validation of the use of IgG antibody response to Anopheles gSG6-p1 salivary peptide to assess human exposure to malaria vector bites in two endemic areas of Cameroon in Central Africa. PLoS One 2020; 15:e0242510. [PMID: 33382730 PMCID: PMC7774847 DOI: 10.1371/journal.pone.0242510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 11/03/2020] [Indexed: 11/25/2022] Open
Abstract
The specific immune response to the Anopheles salivary peptide could be a pertinent and complementary tool to assess the risk of malaria transmission and the effectiveness of vector control strategies. This study aimed to obtain first reliable data on the current state of the Anopheles gSG6-P1 biomarker for assess the level of exposure to Anopheles bites in high malaria endemic areas in Cameroon. Blood smears were collected from people living in the neighborhoods of Youpwe (suburban area, continental) and Manoka (rural area, Island), both areas in the coastal region of Cameroon. Malaria infection was determined using thick blood smear microscopy, whereas the level of specific IgG response to gSG-P1 peptide was assessed by enzyme-linked immunosorbent assay from the dried blood spots. Of 266 (153 from Youpwe, 113 from Manoka) malaria endemic residents (mean age: 22.8±19.8 years, age range: 6 months–94 years, male/female sex ratio: 1/1.2, with Manoka mean age: 23.71±20.53, male/female sex ratio:1/1.13 and Youpwe mean age: 22.12±19.22, male/female sex ratio 1/0.67) randomly included in the study, Plasmodium infection prevalence was significantly higher in Manoka than in Youpwe (64.6% vs 12,4%, p = 0.0001). The anti-gSG6-P1 IgG response showed a high inter-individual heterogeneity and was significantly higher among individuals from Manoka than those from Youpwe (p = 0.023). Malaria infected individuals presented a higher anti-gSG6-P1 IgG antibody response than non-infected (p = 0.0004). No significant difference in the level of specific IgG response to gSG-P1 was observed according to long lasting insecticidal nets use. Taken together, the data revealed that human IgG antibody response to Anopheles gSG-P1 salivary peptide could be also used to assess human exposure to malaria vectors in Central African region. This finding strengthens the relevance of this candidate biomarker to be used for measuring human exposure to malaria vectors worldwide.
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Affiliation(s)
- Glwadys Cheteug
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Department of Microbiology and Parasitology, Faculty of Sciences, University of Buea, Buea, Cameroon
| | | | - Christiane Donkeu
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaounde, Yaounde, Cameroon
| | - Wolfgang Ekoko
- Parasitology and Entomology Research Unit, Department of Animal Biology and Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Martine Oloume
- Department of hematology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | - Estelle Essangui
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Parasitology and Entomology Research Unit, Department of Animal Biology and Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Philippe Nwane
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Sandrine Eveline NSango
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, University of Douala, Douala, Cameroon
| | - Josiane Etang
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Organisation de Coordination pour la Lutte contre les Endemies en Afrique Central, Yaounde, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Sciences, University of Buea, Buea, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, University of Douala, Douala, Cameroon
- * E-mail: ,
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Gislam H, Burnside NG, Brolly M, Deribe K, Davey G, Wanji S, Suh CE, Kemp SJ, Watts MJ, Le Blond JS. Linking soils and human health: geospatial analysis of ground-sampled soil data in relation to community-level podoconiosis data in North West Cameroon. Trans R Soc Trop Med Hyg 2020; 114:937-946. [PMID: 33216129 PMCID: PMC7738663 DOI: 10.1093/trstmh/traa138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/26/2020] [Accepted: 11/02/2020] [Indexed: 12/02/2022] Open
Abstract
Background Podoconiosis is a form of leg swelling, which arises when individuals are exposed over time to red clay soil formed from alkaline volcanic rock. The exact causal agent of the disease is unknown. This study investigates associations between podoconiosis disease data and ground-sampled soil data from North West Cameroon. Methods The mineralogy and elemental concentrations were measured in the soil samples and the data were spatially interpolated. Mean soil values were calculated from a 3 km buffer region around the prevalence data points to perform statistical analysis. Analysis included Spearman's rho correlation, binary logistic regression and principal component analysis (PCA). Results Six elements, barium, beryllium, potassium, rubidium, strontium and thallium, as well as two minerals, potassium feldspar and quartz, were identified as statistically related to podoconiosis. PCA did not show distinct separation between the spatial locations with or without recorded cases of podoconiosis, indicating that other factors such as shoe-wearing behaviour and genetics may significantly influence podoconiosis occurrence and prevalence in North West Cameroon. Conclusion Several soil variables were statistically significantly related to podoconiosis. To further the current study, future investigations will look at the inflammatory pathway response of cells after exposure to these variables.
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Affiliation(s)
- H Gislam
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - N G Burnside
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - M Brolly
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - K Deribe
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, UK.,Centre for Environmental and Developmental Studies and School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - G Davey
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, UK.,Centre for Environmental and Developmental Studies and School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - S Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - C E Suh
- Department of Geology, Environmental Science and Mining, University of Bamenda, Bamenda, Cameroon
| | - S J Kemp
- British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK
| | - M J Watts
- British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK
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Deribe K, Simpson H, Pullan RL, Bosco MJ, Wanji S, Weaver ND, Murray CJL, Newport MJ, Hay SI, Davey G, Cano J. Predicting the environmental suitability and population at risk of podoconiosis in Africa. PLoS Negl Trop Dis 2020; 14:e0008616. [PMID: 32853202 PMCID: PMC7480865 DOI: 10.1371/journal.pntd.0008616] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 09/09/2020] [Accepted: 07/20/2020] [Indexed: 01/17/2023] Open
Abstract
Podoconiosis is a type of tropical lymphedema that causes massive swelling of the lower limbs. The disease is associated with both economic insecurity, due to long-term morbidity-related loss of productivity, and intense social stigma. The geographical distribution and burden of podoconiosis in Africa are uncertain. We applied statistical modelling to the most comprehensive database compiled to date to predict the environmental suitability of podoconiosis in the African continent. By combining climate and environmental data and overlaying population figures, we predicted the environmental suitability and human population at risk of podoconiosis in Africa. Environmental suitability for podoconiosis was predicted in 29 African countries. In the year 2020, the total population in areas suitable for podoconiosis is estimated at 114.5 million people, (95% uncertainty interval: 109.4-123.9) with 16.9 million in areas suitable for both lymphatic filariasis and podoconiosis. Of the total 5,712 implementation units (typically second administrative-level units, such as districts) defined by the World Health Organization in Africa, 1,655 (29.0%) were found to be environmentally suitable for podoconiosis. The majority of implementation units with high environmental suitability are located in Angola (80, 4.8%), Cameroon (170, 10.3%), the DRC (244, 14.7%), Ethiopia (495, 29.9%), Kenya (217, 13.1%), Uganda (116, 7.0%) and Tanzania (112, 6.8%). Of the 1,655 environmentally suitable implementation units, 960 (58.0%) require more detailed community-level mapping. Our estimates provide key evidence of the population at risk and geographical extent of podoconiosis in Africa, which will help decision-makers to better plan more integrated intervention programmes.
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Affiliation(s)
- Kebede Deribe
- Department of Global Heath and Infection, Brighton and Sussex Medical School, Falmer, Brighton, BN1 9PX, United Kingdom
- School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail:
| | - Hope Simpson
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rachel L. Pullan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Mbonigaba Jean Bosco
- Malaria and Other Parasitic Disease Division, Rwanda Biomedical Center–Ministry of Health, Kigali, Rwanda
| | - Samuel Wanji
- Parasites and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Nicole Davis Weaver
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
| | - Christopher J. L. Murray
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Department of Health Metrics Sciences, University of Washington, Seattle, Washington, United States of America
| | - Melanie J. Newport
- Department of Global Heath and Infection, Brighton and Sussex Medical School, Falmer, Brighton, BN1 9PX, United Kingdom
| | - Simon I. Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Department of Health Metrics Sciences, University of Washington, Seattle, Washington, United States of America
| | - Gail Davey
- Department of Global Heath and Infection, Brighton and Sussex Medical School, Falmer, Brighton, BN1 9PX, United Kingdom
- School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jorge Cano
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Boussinesq M, Enyong P, Chounna-Ndongmo P, Njouendou AJ, Pion SD, Rech A, Roberge C, Gaudriault G, Wanji S. Effects of an injectable long-acting formulation of ivermectin on Onchocerca ochengi in zebu cattle. ACTA ACUST UNITED AC 2020; 27:36. [PMID: 32420864 PMCID: PMC7233116 DOI: 10.1051/parasite/2020036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 05/05/2020] [Indexed: 11/14/2022]
Abstract
The availability of a safe macrofilaricidal drug would help to accelerate onchocerciasis elimination. A trial was conducted in Cameroon to evaluate the effects of a subcutaneous injectable long-acting formulation of ivermectin (LAFI) on the microfilariae (mf) and adult stages of Onchocerca ochengi. Ten zebu cattle naturally infected with the parasite were injected subcutaneously with either 500 mg (group A, N = 4), or 1000 mg long-acting ivermectin (group B, N = 4) or the vehicle (group C, N = 2). Skin samples were collected from each animal before, and 6, 12, and 24 months after treatment to measure microfilarial densities (MFDs). Nodules excised before, and 6 and 12 months after treatment were examined histologically to assess the adult worms’ viability and reproductive status. Blood samples were collected at pre-determined time-points to obtain pharmacokinetic data. Before treatment, the average O. ochengi MFDs were similar in the three groups. Six months after treatment, all animals in groups A and B were free of skin mf, whereas those in group C still showed high MFDs (mean = 324.5 mf/g). Only one ivermectin-treated animal (belonging to group A) had skin mf 12 months after treatment (0.9 mf/g). At 24 months, another animal in group A showed skin mf (10.0 mf/g). The histologic examination of nodules at 6 and 12 months showed that LAFI was not macrofilaricidal but had a strong effect on embryogenesis. The new LAFI regimen might be an additional tool to accelerate the elimination of human onchocerciasis in specific settings.
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Affiliation(s)
- Michel Boussinesq
- Recherches Translationnelles sur le VIH et les Maladies Infectieuses (TransVIHMI), UMI233 IRD-U1175 INSERM-Université de Montpellier, BP 64501, 34394 Montpellier Cedex 5, France
| | - Peter Enyong
- Research Foundation for Tropical Diseases and the Environment, PO Box 474, Buea, Cameroon
| | | | - Abdel-Jelil Njouendou
- Research Foundation for Tropical Diseases and the Environment, PO Box 474, Buea, Cameroon
| | - Sébastien David Pion
- Recherches Translationnelles sur le VIH et les Maladies Infectieuses (TransVIHMI), UMI233 IRD-U1175 INSERM-Université de Montpellier, BP 64501, 34394 Montpellier Cedex 5, France
| | - Anthony Rech
- MedinCell S.A., 3 Rue des Frères Lumière, 34830 Jacou, France
| | | | | | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment, PO Box 474, Buea, Cameroon
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Beng AA, Esum ME, Deribe K, Njouendou AJ, Ndongmo PWC, Abong RA, Fru J, Fombad FF, Nchanji GT, Amambo G, Gandjui NTV, Biholong B, Nko'Ayissi G, Mbia P, Akame J, Enyong PI, Reid SD, Tougoue JJ, Zhang Y, Wanji S. Mapping lymphatic filariasis in Loa loa endemic health districts naïve for ivermectin mass administration and situated in the forested zone of Cameroon. BMC Infect Dis 2020; 20:284. [PMID: 32299374 PMCID: PMC7164349 DOI: 10.1186/s12879-020-05009-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/01/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The control of lymphatic filariasis (LF) caused by Wuchereria bancrofti in the Central African Region has been hampered by the presence of Loa loa due to severe adverse events that arise in the treatment with ivermectin. The immunochromatographic test (ICT) cards used for mapping LF demonstrated cross-reactivity with L. loa and posed the problem of delineating the LF map. To verify LF endemicity in forest areas of Cameroon where mass drug administration (MDA) has not been ongoing, we used the recently developed strategy that combined serology, microscopy and molecular techniques. METHODS This study was carried out in 124 communities in 31 health districts (HDs) where L. loa is present. At least 125 persons per site were screened. Diurnal blood samples were investigated for circulating filarial antigen (CFA) by FTS and for L. loa microfilariae (mf) using TBF. FTS positive individuals were further subjected to night blood collection for detecting W. bancrofti. qPCR was used to detect DNA of the parasites. RESULTS Overall, 14,446 individuals took part in this study, 233 participants tested positive with FTS in 29 HDs, with positivity rates ranging from 0.0 to 8.2%. No W. bancrofti mf was found in the night blood of any individuals but L. loa mf were found in both day and night blood of participants who were FTS positive. Also, qPCR revealed that no W. bancrofti but L.loa DNA was found with dry bloodspot. Positive FTS results were strongly associated with high L. loa mf load. Similarly, a strong positive association was observed between FTS positivity and L loa prevalence. CONCLUSIONS Using a combination of parasitological and molecular tools, we were unable to find evidence of W. bancrofti presence in the 31 HDs, but L. loa instead. Therefore, LF is not endemic and LF MDA is not required in these districts.
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Affiliation(s)
- Andrew A Beng
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Mathias E Esum
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, BN1 9PS, UK.
- School of Public Health, College of Health Sciences, Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.
| | - Abdel J Njouendou
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Patrick W C Ndongmo
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Raphael A Abong
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Jerome Fru
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny F Fombad
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Gordon T Nchanji
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Glory Amambo
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Narcisse T V Gandjui
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | | | | | | | - Julie Akame
- Helen Keller International, Yaoundé, Cameroon
| | - Peter I Enyong
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | | | | | - Yaobi Zhang
- Helen Keller International, New York, NY, USA
- Helen Keller International, Regional Office for Africa, Dakar, Senegal
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
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Horton J, Klarmann-Schulz U, Stephens M, Budge PJ, Coulibaly Y, Debrah A, Debrah LB, Krishnasastry S, Mwingira U, Ngenya A, Wanji S, Weerasooriya M, Yahathugoda C, Kroidl I, Deathe D, Majewski A, Sullivan S, Mackenzie C, Nutman TB, Shott JP, Weil G, Ottesen E, Hoerauf A. The design and development of a multicentric protocol to investigate the impact of adjunctive doxycycline on the management of peripheral lymphoedema caused by lymphatic filariasis and podoconiosis. Parasit Vectors 2020; 13:155. [PMID: 32228663 PMCID: PMC7106687 DOI: 10.1186/s13071-020-04024-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/16/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND As new lymphatic filariasis infections are eliminated through mass chemotherapy, previously affected individuals are left with the sequellae, especially chronic progressive lymphoedema. Currently this is managed by careful attention to limb hygiene to prevent infection. Studies over the past 15 years have suggested that the incorporation of doxycycline treatment may arrest or even reverse progression of lymphoedema. Most of this work has been observational or based on small studies, and if this intervention is effective, studies need to be conducted on a larger scale and under diverse geographical and social conditions before it can be incorporated into treatment policy. METHODS/DESIGN The double-blind, placebo-controlled study was designed to investigate the impact of six weeks treatment with doxycycline added to standard limb hygiene on early stage filarial lymphoedema in five sites in Africa and the Indian subcontinent. One site in Cameroon is selected for studying lymphoedema in podoconiosis. Each site was individually powered with the potential to undertake a meta-analysis on completion. Evaluation methods followed those used in Ghana in 2012 with additions resulting from advances in technology. The details of the core protocol and how it was varied to take account of differing situations at each of the sites are provided. The study will enrol up to 1800 patients and will complete in mid-2021. CONCLUSIONS This paper provides details of what challenges were faced during its development and discusses the issues and how they were resolved. In particular, the reasons for inclusion of new technology and the problems encountered with the supply of drugs for the studies are described in detail. By making these details available, it is hoped that the study protocol will help others interested in improving treatment for filarial lymphoedema in the design of future studies. Trial registration India: Clintrials.gov. NCT02929121 registered 10 Oct 2016: https://clinicaltrials.gov/ct2/show/NCT02929121 Mali: Clintrials.gov. NCT02927496 registered 7 Oct 2016: https://clinicaltrials.gov/ct2/show/NCT0292749 Sri Lanka: Clintrials.gov. NCT02929134 registered 10 Oct 2016: https://clinicaltrials.gov/ct2/show/NCT02929134 Ghana: ISRCTN. 14042737 registered 10 July 2017: https://doi.org/10.1186/ISRCTN14042737 Tanzania: ISRCTN. 65756724 registered 21 July 2017: https://doi.org/10.1186/ISRCTN65756724 Cameroon: ISRCTN. 1181662 registered 25 July 2017: https://doi.org/10.1186/ISRCTN11881662.
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Affiliation(s)
- John Horton
- Tropical Projects, 24 The Paddock, Hitchin, UK
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), German Centre for Infection Research (DZIF), Bonn-Cologne Site, University Hospital Bonn, Venusberg-Campus 1, 53105 Bonn, Germany
| | - Mariana Stephens
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | | | - Yaya Coulibaly
- Filariasis Research Unit, International Center for Excellence in Research, ICER-Mali, Bamako, Mali
| | - Alex Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Linda Batsa Debrah
- Department of Microbiology, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Suma Krishnasastry
- Filariasis Research Unit, Govt. T D Medical College, Kerala, 699005 India
| | - Upendo Mwingira
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Abdallah Ngenya
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, SW State Cameroon
| | - Mirani Weerasooriya
- Filariasis Research Training and Services Unit (FRTSU), Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka
| | - Channa Yahathugoda
- Filariasis Research Training and Services Unit (FRTSU), Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka
| | - Inge Kroidl
- Division of Infectious Diseases and Tropical Medicine, University Hospital of the University of Munich (LMU), Munich, Germany
| | - Drew Deathe
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | - Andrew Majewski
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | - Sarah Sullivan
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | - Charles Mackenzie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Joseph P. Shott
- Division of Neglected Tropical Diseases, US Agency for International Development, 1300 Pennsylvania Ave NW, Washington, DC USA
| | - Gary Weil
- Washington University School of Medicine, St. Louis, MO USA
| | - Eric Ottesen
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA USA
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), German Centre for Infection Research (DZIF), Bonn-Cologne Site, University Hospital Bonn, Venusberg-Campus 1, 53105 Bonn, Germany
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Taylor MJ, von Geldern TW, Ford L, Hübner MP, Marsh K, Johnston KL, Sjoberg HT, Specht S, Pionnier N, Tyrer HE, Clare RH, Cook DAN, Murphy E, Steven A, Archer J, Bloemker D, Lenz F, Koschel M, Ehrens A, Metuge HM, Chunda VC, Ndongmo Chounna PW, Njouendou AJ, Fombad FF, Carr R, Morton HE, Aljayyoussi G, Hoerauf A, Wanji S, Kempf DJ, Turner JD, Ward SA. Preclinical development of an oral anti- Wolbachia macrolide drug for the treatment of lymphatic filariasis and onchocerciasis. Sci Transl Med 2020; 11:11/483/eaau2086. [PMID: 30867321 DOI: 10.1126/scitranslmed.aau2086] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/19/2018] [Indexed: 01/04/2023]
Abstract
There is an urgent global need for a safe macrofilaricide drug to accelerate elimination of the neglected tropical diseases onchocerciasis and lymphatic filariasis. From an anti-infective compound library, the macrolide veterinary antibiotic, tylosin A, was identified as a hit against Wolbachia This bacterial endosymbiont is required for filarial worm viability and fertility and is a validated target for macrofilaricidal drugs. Medicinal chemistry was undertaken to develop tylosin A analogs with improved oral bioavailability. Two analogs, A-1535469 and A-1574083, were selected. Their efficacy was tested against the gold-standard second-generation tetracycline antibiotics, doxycycline and minocycline, in mouse and gerbil infection models of lymphatic filariasis (Brugia malayi and Litomosoides sigmodontis) and onchocerciasis (Onchocerca ochengi). A 1- or 2-week course of oral A-1535469 or A-1574083 provided >90% Wolbachia depletion from nematodes in infected animals, resulting in a block in embryogenesis and depletion of microfilarial worm loads. The two analogs delivered comparative or superior efficacy compared to a 3- to 4-week course of doxycycline or minocycline. A-1574083 (now called ABBV-4083) was selected for further preclinical testing. Cardiovascular studies in dogs and toxicology studies in rats and dogs revealed no adverse effects at doses (50 mg/kg) that achieved plasma concentrations >10-fold above the efficacious concentration. A-1574083 (ABBV-4083) shows potential as an anti-Wolbachia macrolide with an efficacy, pharmacology, and safety profile that is compatible with a short-term oral drug course for treating lymphatic filariasis and onchocerciasis.
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Affiliation(s)
- Mark J Taylor
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Thomas W von Geldern
- Global Pharmaceutical Research and Development, AbbVie, North Chicago, IL, USA.,Franciscan Institute for World Health, Franciscan University, Steubenville, OH, USA
| | - Louise Ford
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Kennan Marsh
- Global Pharmaceutical Research and Development, AbbVie, North Chicago, IL, USA
| | - Kelly L Johnston
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Hanna T Sjoberg
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Sabine Specht
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Nicolas Pionnier
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Hayley E Tyrer
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Rachel H Clare
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Darren A N Cook
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Emma Murphy
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Andrew Steven
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - John Archer
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Dominique Bloemker
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Franziska Lenz
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Marianne Koschel
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Alexandra Ehrens
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Haelly M Metuge
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Valerinne C Chunda
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Patrick W Ndongmo Chounna
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Abdel J Njouendou
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Fanny F Fombad
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Robert Carr
- Global Pharmaceutical Research and Development, AbbVie, North Chicago, IL, USA
| | - Howard E Morton
- Global Pharmaceutical Research and Development, AbbVie, North Chicago, IL, USA
| | - Ghaith Aljayyoussi
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.,Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Dale J Kempf
- Global Pharmaceutical Research and Development, AbbVie, North Chicago, IL, USA
| | - Joseph D Turner
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Stephen A Ward
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
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Chunda VC, Ritter M, Bate A, Gandjui NVT, Esum ME, Fombad FF, Njouendou AJ, Ndongmo PWC, Taylor MJ, Hoerauf A, Layland LE, Turner JD, Wanji S. Comparison of immune responses to Loa loa stage-specific antigen extracts in Loa loa-exposed BALB/c mice upon clearance of infection. Parasit Vectors 2020; 13:51. [PMID: 32033624 PMCID: PMC7006431 DOI: 10.1186/s13071-020-3921-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/31/2020] [Indexed: 01/10/2023] Open
Abstract
Background Different immune mechanisms are capable of killing developmental stages of filarial nematodes and these mechanisms are also likely to vary between the primary and a challenge infection. However, the lack of a detailed analysis of cytokine, chemokine and immunoglobulin levels in human loiasis is still evident. Therefore, detailed analysis of immune responses induced by the different developmental stages of Loa loa in immune-competent BALB/c mice will aid in the characterization of distinct immune responses that are important for the immunity against loiasis. Methods Different developmental stages of L. loa were obtained from human peripheral blood (microfilariae, MF), the transmitting vector, Chrysops (larval stage 3, L3) and infected immune-deficient BALB/cRAG2γc−/− mice (L4, L5, adult worms). Groups of wildtype BALB/c mice were then injected with the isolated stages and after 42 days post-infection (pi), systemic cytokine, chemokine and immunoglobulin levels were determined. These were then compared to L. loa-specific responses from in vitro re-stimulated splenocytes from individual mice. All parameters were determined using Luminex technology. Results In a pilot study, BALB/c mice cleared the different life stages of L. loa within 42 days pi and systemic cytokine, chemokine and immunoglobulin levels were equal between infected and naive mice. Nevertheless, L. loa-specific re-stimulation of splenocytes from mice infected with L5, MF or adult worms led to induction of Th2, Th17 and chemokine secretion patterns. Conclusions This study shows that although host immunity remains comparable to naive mice, clearance of L. loa life-cycle development stages can induce immune cell memory leading to cytokine, chemokine and immunoglobulins secretion patterns which might contribute to immunity and protection against reinfection.![]()
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Affiliation(s)
- Valerine C Chunda
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), Medical Faculty, University of Bonn, Bonn, Germany.
| | - Ayukenchengamba Bate
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Narcisse V T Gandjui
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Mathias E Esum
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Fanny F Fombad
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Abdel J Njouendou
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Patrick W C Ndongmo
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
| | - Mark J Taylor
- Centre for Drugs and Diagnostics Research, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), Medical Faculty, University of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), Bonn-Cologne partner site, Bonn, Germany
| | - Laura E Layland
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), Medical Faculty, University of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), Bonn-Cologne partner site, Bonn, Germany
| | - Joseph D Turner
- Centre for Drugs and Diagnostics Research, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Samuel Wanji
- Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon
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Njouendou AJ, Ritter M, Kien CA, Esum ME, Ndongmo WPC, Fombad FF, Gandjui NVT, Njiokou F, Enyong P, Pfarr K, Turner J, Layland LE, Hoerauf A, Wanji S. Dataset on in vitro maintenance of Mansonella perstans microfilariae and drug testing. Data Brief 2019; 28:104930. [PMID: 31886361 PMCID: PMC6920388 DOI: 10.1016/j.dib.2019.104930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 11/26/2022] Open
Abstract
Endemic communities of Mansonella perstans infections have been neglected since associated pathology remains undefined. Consequently, improvements in drug therapy have also been ignored despite a large number of infected individuals in areas of Cameroon. Thus, we established an in vitro system to culture M. perstans microfilariae (Mf); the transmission stage of infection. In short, we compared the ability of two renowned culture media (Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640)) to sustain Mf in culture. Media were supplemented with 10% fetal bovine serum (FBS) and monkey kidney epithelial cells (LLC-MK2) were used as feeder cells. As readout we assessed Mf survival and motility using a standardised microscopy assessment strategy. Moreover, this in vitro culture system was used to test susceptibility levels of microfilariae to different chemotherapeutic agents. Parasite motility was scored daily using a graded system and analysed using the average motility and area under the motility curve of M. perstans Mf. These datasets were analysed and discussed in detail in the related article entitled: “In vitro maintenance of Mansonella perstans microfilariae and its relevance for drug screening” [1].
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Affiliation(s)
- Abdel Jelil Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Chi Anizette Kien
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Mathias E Esum
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Winston Patrick Chounna Ndongmo
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Fanny Fri Fombad
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Narcisse Victor T Gandjui
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
| | - Peter Enyong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany.,German Center for Infection Research (DZIF), Bonn - Cologne Partner Site, Bonn, Germany
| | - Joseph Turner
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, UK
| | - Laura E Layland
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany.,German Center for Infection Research (DZIF), Bonn - Cologne Partner Site, Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany.,German Center for Infection Research (DZIF), Bonn - Cologne Partner Site, Bonn, Germany
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
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