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Opoku M, de Souza DK. Identification and characterisation of Mansonella perstans in the Volta Region of Ghana. PLoS One 2024; 19:e0295089. [PMID: 38848396 PMCID: PMC11161070 DOI: 10.1371/journal.pone.0295089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 05/09/2024] [Indexed: 06/09/2024] Open
Abstract
Mansonella spp. have been reported to have a wide global distribution. Despite the distribution and co-occurrence with other filarial parasites like Wuchereria bancrofti, Onchocerca volvulus and Loa loa, it is given little attention. There are few surveillance programmes for assessing the distribution of mansonellosis, due to the associated mild to no symptoms experienced by infected people. However, addressing this infection is critical to the onchocerciasis control program as current rapid diagnostic tools targeting O. volvulus have the tendency to cross react with Mansonella species. In this study we identified and characterised M. perstans from five sites in two districts in the Volta Region of Ghana and compared them to samples from other regions. Night blood smears and filter blood blots were obtained from individuals as part of a study on lymphatic filariasis. The Giemsa-stained smears were screened by microscopy for the presence of filarial parasites. Genomic DNA was extracted from blood blots from 39 individuals that were positive for M. perstans and Nested PCR targeting the internal spacer 1 (ITS-1) was conducted. Of these, 30 were sequenced and 24 sequences were kept for further analysis. Phylogenetic analysis of 194 nucleotide positions showed no differences in the samples collected. The similarities suggests that there could be one species in this area. However, more robust studies with larger sample sizes are required to draw such conclusions. We also observed a clustering of the samples from Ghana with reference sequences from Africa and Brazil, suggesting they could be related. This study draws further attention to a neglected infection, presents the first characterisation of M. perstans in Ghana and calls for more population-based studies across different geographical zones to ascertain species variations and disease distribution.
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Affiliation(s)
- Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- Environment and Genetics Department, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Dziedzom K. de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
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Burger G, Adamou R, Kreuzmair R, Ndoumba WN, Mbassi DE, Mouima AMN, Tabopda CM, Adegnika RM, More A, Okwu DG, Mbadinga LBD, Calle CL, Veletzky L, Metzger WG, Mordmüller B, Ramharter M, Mombo-Ngoma G, Adegnika AA, Zoleko-Manego R, McCall MBB. Eosinophils, basophils and myeloid-derived suppressor cells in chronic Loa loa infection and its treatment in an endemic setting. PLoS Negl Trop Dis 2024; 18:e0012203. [PMID: 38771861 PMCID: PMC11147522 DOI: 10.1371/journal.pntd.0012203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 06/03/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND Chronic infection by Loa loa remains an unsolved immunological paradox. Despite harboring subcutaneously migrating adult worms and often high densities of microfilariae, most patients experience only relatively mild symptoms, yet microfilaricidal treatment can trigger life-threatening inflammation. Here, we investigated innate cell populations hypothesized to play a role in these two faces of the disease, in an endemic population in Gabon. METHODOLOGY/PRINCIPAL FINDINGS We analyzed numbers and activation of eosinophils and basophils, as well as myeloid-derived suppressor cell (MDSC) subsets and associated circulating cytokine levels by flow cytometry in sex- and age-matched L. loa-uninfected (LL-), -amicrofilaraemic (MF-) and -microfilaraemic (MF+) individuals (n = 42), as well as microfilaraemic individuals treated with albendazole (n = 26). The percentage of eosinophils was lower in LL- (3.0%) than in the combined L. loa-infected population, but was similar in MF+ (13.1%) and MF- (12.3%). Upon treatment of MF+, eosinophilia increased from day 0 (17.2%) to day 14 (24.8%) and had decreased below baseline at day 168 (6.3%). Expression of the eosinophil activation marker CD123 followed the same pattern as the percentage of eosinophils, while the inverse was observed for CD193 and to some extent CD125. Circulating IL-5 levels after treatment followed the same pattern as eosinophil dynamics. Basophil numbers did not differ between infection states but increased after treatment of MF+. We did not observe differences in MDSC numbers between infection states or upon treatment. CONCLUSIONS/SIGNIFICANCE We demonstrate that both chronic infection and treatment of L. loa microfilaraemia are associated with eosinophil circulation and distinct phenotypical activation markers that might contribute to inflammatory pathways in this setting. In this first ever investigation into MDSC in L. loa infection, we found no evidence for their increased presence in chronic loiasis, suggesting that immunomodulation by L. loa is induced through other pathways.
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Affiliation(s)
- Gerrit Burger
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Rafiou Adamou
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Ruth Kreuzmair
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Wilfrid Ndzebe Ndoumba
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
| | - Dorothea Ekoka Mbassi
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
- Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | - Ayong More
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Dearie Glory Okwu
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
| | | | | | - Luzia Veletzky
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | | | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
- Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
| | - Ayola Akim Adegnika
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner site Tübingen, Tübingen Germany
| | - Rella Zoleko-Manego
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- German Center for Infection Research, Partner sites Hamburg-Borstel-Lübeck-Riems, Germany
- Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Matthew B. B. McCall
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
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Hildebrandt TR, Davi SD, Kabwende AL, Endamne LR, Mehmel E, Rakotonirinalalao M, Alabi A, Manego RZ, Kremsner PG, Lell B, Adegnika AA, Mombo-Ngoma G, Mischlinger J, Agnandji ST, Ramharter M. Evaluation of knowledge, attitude and practices towards loiasis in the rural community of Sindara, in central African Gabon. PLoS Negl Trop Dis 2024; 18:e0012109. [PMID: 38781277 PMCID: PMC11265652 DOI: 10.1371/journal.pntd.0012109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 07/23/2024] [Accepted: 03/27/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND More than 20 million people are infected with L. loa, and around 40 million live in high or intermediate-risk areas in West- and Central Africa. Although loiasis is associated with significant morbidity and excess mortality, little is known about the perception of loiasis by affected communities. This study assessed the knowledge, attitudes, and practices in the rural population of Sindara, Gabon, a region characterized by high loiasis prevalence. METHODS A community-based cross-sectional survey was conducted in Gabon between January and June 2022. During systematic door-to-door visits, randomly selected inhabitants were invited to participate in this questionnaire based survey. Venous blood was collected at midday from all participants for microscopic detection of filarial infection and clinical signs of loiasis were assessed. RESULTS A total of 150 participants were recruited, of which 66% were infected by L. loa. While almost everyone had some knowledge about L. loa, 72% of the participants understood that L. loa is a parasitic worm. The transmission of L. loa via the deer fly was known to only 21% of participants. The most frequently mentioned clinical symptoms attributed to loiasis were itching (84%), eye worm migration (59%), and conjunctivitis-like symptoms (53%). Participants who experienced migratory loiasis had better knowledge of loiasis and considered it as more serious. Traditional and herbal medicine was reported most often as an available treatment option (72%). While the formal healthcare sector was mentioned as the preferred treatment provider, 60% of the reported infections were treated by traditional medical practitioners. CONCLUSION Loiasis is in general well known by this community residing in a region of high L. loa transmission. Important gaps in knowledge were discovered foremost regarding the mode of transmission. The available healthcare system does not seem to provide adequate management for loiasis.
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Affiliation(s)
- Teite Rebecca Hildebrandt
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Saskia Dede Davi
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | | | - Lilian Rene Endamne
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Esther Mehmel
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Maximilian Rakotonirinalalao
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Ayodele Alabi
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rella Zoleko Manego
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Peter G. Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Medical University of Vienna, Vienna, Austria
| | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- German Center for Infection Research, Partner Site Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Johannes Mischlinger
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Michael Ramharter
- Center for Tropical Medicine, Bernhard-Nocht Institute for Tropical Medicine and I. Department of Medicine University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research, Partner Sites Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
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M'Bondoukwé NP, Owono-Medang M, Moussavou-Boussougou MN, Akoue Y, Migueba V, Bulaev D, Neven A, James LAJ, Ntsame Ella SA, Mawili-Mboumba DP, Atsame J, Vaillant M, Bouyou Akotet MK. Low diagnostic performance of thick blood smears of 50 µl in comparison with direct examination of 10 µl blood and the leukoconcentration technique of 5ml blood among loiasis-suspected patients with low microfilaremia in Gabon, Central Africa, using the STARD-BLCM guidelines. Parasit Vectors 2024; 17:138. [PMID: 38491557 PMCID: PMC10943916 DOI: 10.1186/s13071-023-06089-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/08/2023] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND The aim of this study was to determine performance indicators of thick blood smears of 50 µl (TBS-50), following the Standards for the Reporting of Diagnostic Accuracy Studies-Bayesian Latent Class Model (STARD-BLCM) guidelines. TBS-50 was compared with two common parasitological techniques-direct examination of 10 µl blood and a leukoconcentration of 5 ml-for the diagnosis of microfilaremic loiasis. METHODS The study population was recruited among patients of the Department of Parasitology-Mycology-Tropical Medicine over a period of 1 year. Age, sex, symptoms, and eosinophilia variables were recorded from laboratory registers and medical files. Direct examination of 10 µl of blood, TBS-50, and the leukoconcentration technique with 5 ml of blood were performed for each patient. The classical formula and BLCM were used to determine the diagnostic accuracy of the three techniques as well as the prevalence of microfilaremic loiasis. Three models were built within the framework of BLCM-the BLCM model I and alternative models II and III-for sensitivity analysis. RESULTS In total, 191 patients consented to be included. The direct blood examination and TBS-50 yielded comparable qualitative and quantitative results. Hence, they are reported together. The prevalence of Loa loa microfilaremia was 9.4% (95% CI 5.7-14.5; n = 18/191) with direct blood examination/TBS-50 and 12.6% [8.2-18.1] (n = 24/191) for leukoconcentration. Comparing TBS-50 with the leukoconcentration method using the classical formula, the sensitivity was 75.0% [53.3-90.2], specificity was 100.0% [97.8-100.0], the positive predictive value was 100.0% [81.5-100.0], and the negative predictive value was 96.5% [92.6-98.7]. The prevalence of microfilaremic loiasis was estimated at 9.7% [6.2-13.7] using BLCM model I. The outputs of BLCM model I showed sensitivity of 78.9% [65.3-90.3], specificity of 100.0% [99.3-100.0], a positive predictive value of 99.1% [87.2-100.0], and a negative predictive value of 93.0% [87.3-97.7] for direct blood examination/TBS-50. CONCLUSIONS TBS-50 demonstrates low sensitivity relative to two other techniques. In one in five cases, the result will be falsely declared negative using these methods. However, this method can be deployed with limited funds.
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Affiliation(s)
- Noé Patrick M'Bondoukwé
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon.
| | - Matthieu Owono-Medang
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | - Marie Noëlle Moussavou-Boussougou
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | - Yvan Akoue
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | - Valentin Migueba
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | - Dmitry Bulaev
- Competence Centre for Methodology and Statistics, Luxembourg Institute of Health, 1A-B Rue Thomas Edison, 1445, Strassen, Luxembourg
| | - Anouk Neven
- Competence Centre for Methodology and Statistics, Luxembourg Institute of Health, 1A-B Rue Thomas Edison, 1445, Strassen, Luxembourg
| | - Luice Aurtin Joel James
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | | | - Denise Patricia Mawili-Mboumba
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
| | - Julienne Atsame
- Programme de Lutte Contre les Maladies Parasitaires, Ministère de la Santé du Gabon, Libreville, Gabon
| | - Michel Vaillant
- Competence Centre for Methodology and Statistics, Luxembourg Institute of Health, 1A-B Rue Thomas Edison, 1445, Strassen, Luxembourg
| | - Marielle Karine Bouyou Akotet
- Department of Parasitology-Mycology-Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, 4009, Libreville, Gabon
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Parkouda S, Saidou M, Bisseye C. Microfilariae Prevalence and its Association with Anemia Among First-time Blood Donors in Lambaréné, Gabon. Balkan Med J 2024; 41:139-143. [PMID: 38259115 PMCID: PMC10913112 DOI: 10.4274/balkanmedj.galenos.2023.2023-9-86] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024] Open
Abstract
Background Anemia remains a significant public health concern in Gabon, particularly among children, adolescents, and females. Gabon is also home to two major species of filarial worms, Loa and Mansonella spp., which cause microfilaremia. The epidemiological nexus between hemoglobin (Hb) concentrations and microfilaremia in Gabonese first-time blood donors remains unknown. Aims To understand better the epidemiological relationship between anemia and microfilaremia to improve donor selection and management protocols. Study Design A retrospective cohort study. Methods This study was conducted among first-time blood donors in Lambaréné between March 2018 and October 2019. Participants aged 16-65 years old and weighing a minimum of 50 kg were enrolled using standard donor selection criteria. An automatic hematological analyzer was used to quantify Hb concentrations, and microscopy techniques were used to detect the presence of microfilariae. Results Microfilariae were found in 4.8% (35/723) of the 723 first-time blood donors from Lambaréné. Anemia was classified as mild in 35.5% (257/723) and moderate in 1% (7/723). No significant associations were found between the distribution of microfilariae and variables such as age, sex, socioprofessional classification, marital status, or residence. Blood group O donors had a higher prevalence of microfilariae (6%) than non-O donors (2.7%). However, the observed difference was not statistically significant (AOR =2.3, p = 0.052). Furthermore, microfilariae were associated with increased moderate anemia (3.7% vs. 29%, AOR =15.6, p = 0.003). Conclusion Our findings highlight microfilaremia as a possible etiological cause of anemia among Gabonese blood donors, emphasizing the need for further research and a potential review of donor management strategies.
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Affiliation(s)
- Soulemane Parkouda
- Biomedical Laboratory, Centre Hospitalier Régional Georges Rawiri, Lambaréné, Gabon
| | - Mahmoudou Saidou
- Biostatistiques, Centre de Recherches Medicales de Lambaréné, Lambaréné, Gabon
| | - Cyrille Bisseye
- Biologie/Unité de Recherche en Sciences Biologiques, Université des Sciences et Techniques de Masuku, Franceville, Gabon
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Ramharter M, Butler J, Mombo-Ngoma G, Nordmann T, Davi SD, Zoleko Manego R. The African eye worm: current understanding of the epidemiology, clinical disease, and treatment of loiasis. THE LANCET. INFECTIOUS DISEASES 2024; 24:e165-e178. [PMID: 37858326 DOI: 10.1016/s1473-3099(23)00438-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 10/21/2023]
Abstract
Loa loa, the African eye worm, is a filarial pathogen transmitted by blood-sucking flies of the genus Chrysops. Loiasis primarily affects rural populations residing in the forest and adjacent savannah regions of central and west Africa, where more than 20 million patients are chronically infected in medium and high transmission regions. For a long time, loiasis has been regarded as a relatively benign condition. However, morbidity as measured by disability-adjusted life-years lost might be as high as 400 per 100 000 residents, and the population attributable fraction of death is estimated at 14·5% in highly endemic regions, providing unequivocal evidence for the substantial disease burden that loiasis exerts on affected communities. The clinical penetrance of loiasis is variable and might present with the classic signs of eye worm migration or transient Calabar swellings, but might include common, unspecific symptoms or rare but potentially life-threatening complications. Although adult worm migration seems most closely linked to symptomatic disease, high levels of microfilaraemia are associated with clinically important complications and death. Loiasis remains difficult to diagnose, treat, and control due to an absence of reliable point-of-care diagnostic assays, safe and efficacious drugs, and cost-effective prevention strategies. This Review summarises the major advances in our understanding of loiasis made over the past decade and highlights the many gaps that await to be addressed urgently.
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Affiliation(s)
- Michael Ramharter
- Department of Clinical Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany; Division of Tropical Medicine, I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Centre de Recherche Médicale de Lambaréné, Lambaréné, Gabon; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany.
| | | | - Ghyslain Mombo-Ngoma
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany; Division of Tropical Medicine, I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Centre de Recherche Médicale de Lambaréné, Lambaréné, Gabon; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Tamara Nordmann
- Department of Clinical Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany; Division of Tropical Medicine, I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Saskia Dede Davi
- Department of Clinical Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany; Division of Tropical Medicine, I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Rella Zoleko Manego
- Department of Clinical Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany; Division of Tropical Medicine, I Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Centre de Recherche Médicale de Lambaréné, Lambaréné, Gabon
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7
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Veletzky L, Eberhardt KA, Hergeth J, Stelzl DR, Zoleko Manego R, Kreuzmair R, Burger G, Mischlinger J, McCall MBB, Mombo-Ngoma G, Adegnika AA, Agnandji ST, Matsiegui PB, Lell B, Kremsner P, Mordmüller B, Tappe D, Ramharter M. Analysis of diagnostic test outcomes in a large loiasis cohort from an endemic region: Serological tests are often false negative in hyper-microfilaremic infections. PLoS Negl Trop Dis 2024; 18:e0012054. [PMID: 38484012 DOI: 10.1371/journal.pntd.0012054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 03/26/2024] [Accepted: 03/07/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND The parasitic disease loiasis is associated with significant morbidity and mortality. Individuals with hyper-microfilaremia (greater than 20,000 microfilariae per mL of blood) may suffer from serious treatment-related or spontaneous adverse events. Diagnosing loiasis remains complex and primarily relies on direct parasite detection. In this study, we analyzed the performance of various diagnostic tests and the influence of parasitological and clinical factors on test outcomes in samples from individuals living in an endemic region. METHODS Data and samples were collected from rural Gabon. Loiasis was defined as either detectable microfilaremia, or a positive history of eyeworm as assessed by the RAPLOA questionnaire. Diagnostic testing included a quantitative PCR (qPCR) for detection of Loa loa DNA in blood samples, an in-house crude L. loa antigen IgG ELISA, and a rapid test for antibodies against the Ll-SXP-1 antigen (RDT). Sensitivity and specificity were determined for each test and factors potentially influencing outcomes were evaluated in an exploratory analysis. RESULTS ELISA, RDT and qPCR results were available for 99.8%, 78.5%, and 100% of the 1,232 participants, respectively. The ELISA and RDT had only modest diagnostic accuracy. qPCR was specific for L. loa microfilaremia and Cycle threshold values correlated with microfilarial density. Anti-L. loa IgG levels were highest in occult loiasis, and antibody levels correlated inversely with L. loa microfilarial density as did RDT line intensities. Only 84.6% and 16.7% of hyper-microfilaremic individuals tested positive by ELISA (11/13) and RDT (2/12), respectively. CONCLUSION None of the tests demonstrated high sensitivity and specificity for loiasis. Indirect diagnostic assays were characterized by low specificity. Additionally, hyper-microfilaremic individuals often tested negative by RDT and ELISA, indicating that these tests are not suitable for individual case management in endemic populations.
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Affiliation(s)
- Luzia Veletzky
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
| | - Kirsten Alexandra Eberhardt
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Daniel Robert Stelzl
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rella Zoleko Manego
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Ruth Kreuzmair
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Gerrit Burger
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
- Department of Internal Medicine, Infectious Diseases, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
| | - Johannes Mischlinger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Matthew B B McCall
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Radboud University Medical Center, Department of Medical Microbiology, HB Nijmegen, The Netherlands
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | | | - Bertrand Lell
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Peter Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
- Radboud University Medical Center, Department of Medical Microbiology, HB Nijmegen, The Netherlands
| | - Dennis Tappe
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
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8
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Moutongo Mouandza R, Mourou JR, Moutombi Ditombi B, Roger Sibi Matotou H, Ekomi B, Bouyou-Akotet MK, Mawili-Mboumba DP. Sociodemographics, Clinical Factors, and Biological Factors Associated with Loiasis in Endemic Onchocerciasis Areas in Southern Gabon. Am J Trop Med Hyg 2023; 109:850-857. [PMID: 37339766 PMCID: PMC10551092 DOI: 10.4269/ajtmh.22-0558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 04/22/2023] [Indexed: 06/22/2023] Open
Abstract
To implement the appropriate strategies for scale-up interventions to eliminate onchocerciasis without severe adverse events, clinical and biological factors associated with loiasis were analyzed in onchocerciasis-endemic areas. Blood was collected from volunteers after examination by a physician. Detection of microfilariae and measurement of Ov16 IgG4 were performed using direct microscopic examination of blood and onchocerciasis rapid test detection, respectively. Areas with sporadic, hypoendemic, and hyperendemic onchocerciasis endemicity were found. Participants with microfilaremia were considered microfilaremic, and those without microfilaremia were seen as amicrofilaremic. Of the 471 study participants, 40.5% (n = 191) had microfilariae. Among them, Mansonella spp. was the most common (78.2%, n = 147), followed by Loa loa (41.4%, n = 79). The association between the two species represented 18.3% (n = 35). The specific immunoglobulins of Onchocerca volvulus were detected in 24.2% of participants (n = 87/359). Overall prevalence of L. loa was 16.8%. Hypermicrofilaremia was found in 3% (N = 14), and one participant had more than 30,000 microfilaremiae per milliliter. The frequency of L. loa did not vary according to the level of onchocerciasis transmission. Pruritus was the most common clinical sign (60.5%, n = 285) reported, mainly in microfilaremic participants (72.2%, n = 138/191). The prevalence of L. loa microfilaria in the study population was below the threshold at risk for the occurrence of serious side effects due to ivermectin. Clinical manifestations frequently observed could be exacerbated by microfilaremia in areas where onchocerciasis transmission is high.
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Affiliation(s)
- Reinne Moutongo Mouandza
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Jean Romain Mourou
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Bridy Moutombi Ditombi
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Hadry Roger Sibi Matotou
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Bernadette Ekomi
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Marielle Karine Bouyou-Akotet
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Denise Patricia Mawili-Mboumba
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
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9
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Eyang-Assengone ER, Makouloutou-Nzassi P, Mbou-Boutambe C, Bangueboussa F, Atsame J, Boundenga L. Status of Onchocerciasis Elimination in Gabon and Challenges: A Systematic Review. Microorganisms 2023; 11:1946. [PMID: 37630506 PMCID: PMC10458829 DOI: 10.3390/microorganisms11081946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/19/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Control and treatment programs (CDTI) have been set up nationally in all endemic countries to overcome the impact of onchocerciasis on the affected populations. However, Gabon must still succeed in setting up real onchocerciasis control programs. Here, various database articles have been used to provide the scientific community with a summary document showing the mapping of this disease in Gabon. The articles dealing with onchocerciasis, animal reservoirs, surveillance, and elimination were analyzed. Results showed that little research has been performed. Most studies are concentrated in one region (The area of Lastourville). In addition, we observed that the distribution of the disease varies significantly across the country. Indeed, specific environments present a hyper-endemicity of the disease, while others are meso and hypo-endemic. So, we found some departments with a prevalence ranging from 0% to over 20%; within them, villages had infection levels comprising 10% to 60%, indicating potential hotspots. Vectors activities were studied in some areas. This paper showed the challenges encountered in the country to eliminate this disease. One solution is a deeper understanding of the disease's bioecology to establish effective health policies to eliminate onchocerciasis in Gabon effectively.
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Affiliation(s)
- Elsa-Rush Eyang-Assengone
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon; (P.M.-N.); (C.M.-B.); (F.B.)
| | - Patrice Makouloutou-Nzassi
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon; (P.M.-N.); (C.M.-B.); (F.B.)
- Département de Biologie et Ecologie Animale, Institut de Recherche en Ecologie Tropicale (IRET/CENAREST), Libreville BP 13354, Gabon
| | - Clark Mbou-Boutambe
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon; (P.M.-N.); (C.M.-B.); (F.B.)
| | - Félicien Bangueboussa
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon; (P.M.-N.); (C.M.-B.); (F.B.)
| | - Julienne Atsame
- Programme de Lutte Contre les Maladies Parasitaires, Ministère de la Santé du Gabon, Libreville BP 2434, Gabon;
| | - Larson Boundenga
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville BP 769, Gabon; (P.M.-N.); (C.M.-B.); (F.B.)
- Département d’anthropologie, Université de Durham, South Road, Durham DH1 3LE, UK
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10
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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. FRONTIERS IN TROPICAL DISEASES 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] [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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11
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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. FRONTIERS IN TROPICAL DISEASES 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] [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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12
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Dieki R, Eyang Assengone ER, Nsi Emvo E, Akue JP. Profile of loiasis infection through clinical and laboratory diagnostics: the importance of biomarkers. Trans R Soc Trop Med Hyg 2022; 117:349-357. [PMID: 36520072 PMCID: PMC10153730 DOI: 10.1093/trstmh/trac116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 10/30/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022] Open
Abstract
ABSTRACT
Background
Detection of Loa loa microfilariae in peripheral blood is insensitive given only 30% of individuals are microfilaraemic while 70% are amicrofilaraemic with a variety of clinical signs. Biomarkers may improve the diagnosis of loiasis.
Methods
A total of 545 individuals exposed to L. loa were analysed using clinical data collected through a questionnaire (requesting information on eye worm, Calabar swelling, pruritis) and detection of microfilariae, immunoglobulin G4 (IgG4), DNA and antigens using microscopy, enzyme-linked immunosorbent assay (ELISA), quantitative polymerase chain reaction (qPCR) and Western blot, respectively.
Results
The results revealed that the rates of detection of L. loa microfilariae in the blood, of DNA by qPCR, of IgG4 by ELISA and of antigen by Western blot were 4.7%, 5.5%, 15.60% and 10.09%, respectively.
Conclusions
This study showed that clinical signs based on a questionnaire are highly subjective. Therefore it is imperative to use IgG4 and DNA biomarkers as well as antigens detected by Western blot to identify individuals infected with L. loa.
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Affiliation(s)
- Roland Dieki
- Department of Parasitology, Centre International of Medical Research of Franceville , Franceville , Gabon
- Department of Chemistry, Université des Sciences et Techniques de Masuku (USTM) , Franceville , Gabon
| | - E R Eyang Assengone
- Department of Parasitology, Centre International of Medical Research of Franceville , Franceville , Gabon
| | - E Nsi Emvo
- Department of Chemistry, Université des Sciences et Techniques de Masuku (USTM) , Franceville , Gabon
| | - J P Akue
- Department of Parasitology, Centre International of Medical Research of Franceville , Franceville , Gabon
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13
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Pongui Ngondza B, Koumba Lengongo JV, Mickala P, M'bondoukwé NP, Ndong Ngomo JM, Moutombi Ditombi BC, Mawili-Mboumba DP, Bouyou-Akotet MK. Prevalence and risk factors for blood filariasis among HIV-infected adults in Gabon, Central Africa: a pilot study. Trans R Soc Trop Med Hyg 2022; 116:1015-1021. [PMID: 35474144 DOI: 10.1093/trstmh/trac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/20/2022] [Accepted: 03/28/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The level of blood filariasis parasitaemia as well as the frequency of and the relationship between cotrimoxazole prophylaxis (CTX-P), antiretroviral therapy (ART) intake and CD4 cell count among people living with human immunodeficiency virus (PLHIV) in rural areas of Gabon were being studied. METHODS Sociodemographic data and recent biological tests of PLHIV and HIV-negative participants were collected. Loa loa and Mansonella perstans microfilaria were detected by direct microscopy examination and leucoconcentration. RESULTS Overall, 209 HIV-positive and 148 HIV-negative subjects were enrolled. The overall prevalence of microfilaria was comparable between PLHIV (19.9% [n=41/206]) and HIV-negative participants (14.8% [n=22/148]) (p=0.2). The L. loa infection rate was comparable between HIV-positive (9.2%) and HIV-negative participants (6.8%) (p=0.2), while the M. perstans infection rate was 14-fold higher among PLHIV (p<0.01). L. loa parasitaemia was 6-fold lower in PLHIV receiving CTX-P (median 150 mf/mL [interquartile range {IQR} 125-350]) than in patients without (900 [550-2225]) (p<0.01). Among subjects with a CD4 cell count <200 cells/μL, the prevalence of M. perstans was 7-fold higher than that of L. loa (20.6% vs 2.9%). CONCLUSIONS This study suggests a similar exposure to L. loa infection of PLHIV and HIV-negative patients while M. perstans is more frequently found in HIV-positive individuals, notably those with a CD4 count <200 cells/μL.
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Affiliation(s)
- B Pongui Ngondza
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - J V Koumba Lengongo
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - P Mickala
- Department of Biology, Faculty of Sciences, Université des Sciences et Techniques de Masuku, BP 901, Franceville, Gabon
| | - N P M'bondoukwé
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - J M Ndong Ngomo
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - B C Moutombi Ditombi
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - D P Mawili-Mboumba
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - M K Bouyou-Akotet
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
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14
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Veletzky L, Eberhardt KA, Hergeth J, Stelzl DR, Zoleko Manego R, Mombo-Ngoma G, Kreuzmair R, Burger G, Adegnika AA, Agnandji ST, Matsiegui PB, Boussinesq M, Mordmüller B, Ramharter M. Distinct loiasis infection states and associated clinical and hematological manifestations in patients from Gabon. PLoS Negl Trop Dis 2022; 16:e0010793. [PMID: 36121900 PMCID: PMC9521832 DOI: 10.1371/journal.pntd.0010793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 09/29/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
Background Loiasis–a filarial disease endemic in Central and West Africa–is increasingly recognized as significant individual and public health concern. While the understanding of the disease characteristics remains limited, significant morbidity and excess mortality have been demonstrated. Here, we characterize clinical and hematological findings in a large cohort from Gabon. Methods Loiasis-related clinical manifestations and microfilaremia, hemoglobin and differential blood counts were recorded prospectively during a cross-sectional survey. For analysis, participants were categorized into distinct infection states by the diagnostic criteria of eye worm history and microfilaremia. Results Analysis of data from 1,232 individuals showed that occurrence of clinical and hematological findings differed significantly between the infection states. Eye worm positivity was associated with a wide range of clinical manifestations while microfilaremia by itself was not. Loa loa infection was associated with presence of eosinophilia and absolute eosinophil counts were associated with extent of microfilaremia (p-adj. = 0.012, ß-estimate:0.17[0.04–0.31]). Conclusions Loiasis is a complex disease, causing different disease manifestations in patients from endemic regions. The consequences for the affected individuals or populations as well as the pathophysiological consequences of correlating eosinophilia are largely unknown. High-quality research on loiasis should be fostered to improve patient care and understanding of the disease. Loiasis is a parasitic disease, endemic in parts of Western and Central Africa. While the disease has traditionally been considered to be benign, only recently significant disease morbidity and mortality have been shown. Most of the knowledge about loiasis, however, stems from reports on returning travelers, while comprehensive data from patients living in endemic areas are missing. Blood microfilaremia and reported eye worm are important diagnostic manifestations of the disease, but they can occur independent of each other in affected individuals. We analyzed hematological and clinical findings according to loiasis infection states, comprising reported eye worm and microfilaremia positivity, in a large group of individuals from a highly endemic area. While we found that all loiasis infection states were significantly associated with absolute blood eosinophilia, the eosinophilia was more pronounced in microfilaremic loiasis. Further, there was an association between the extent of microfilaremia and absolute eosinophilia. Analyzing the frequency of clinical disease manifestations, we found that eye worm positive loiasis was associated with a range of symptoms, but microfilaremic loiasis was not. Summarizing, even in highly endemic populations different loiasis infection states are associated with distinct disease manifestations, underlining that loiasis is a versatile and indeed relevant disease.
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Affiliation(s)
- Luzia Veletzky
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center For Infection Research (DZIF), Hamburg-Borstel-Riems, Germany
- * E-mail: (LV); (MR)
| | - Kirsten Alexandra Eberhardt
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Daniel Robert Stelzl
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rella Zoleko Manego
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Ruth Kreuzmair
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Gerrit Burger
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | | | - Michel Boussinesq
- Institut de Recherche pour le Développement (IRD), UMI 233-TransVIHMI-Inserm U1175-University of Montpellier, Montpellier, France
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany & German Center for Infection Research, partner site Tübingen, Tübingen, Germany
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center For Infection Research (DZIF), Hamburg-Borstel-Riems, Germany
- * E-mail: (LV); (MR)
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15
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Ekoka Mbassi FA, Mombo-Ngoma G, Ndoumba WN, Yovo EK, Eberhardt KA, Ekoka Mbassi D, Adegnika AA, Agnandji ST, Bouyou-Akotet MK, Ramharter M, Zoleko-Manego R. Performance of Field's Stain Compared with Conventional Giemsa Stain for the Rapid Detection of Blood Microfilariae in Gabon. Am J Trop Med Hyg 2022; 107:383-387. [PMID: 35895407 PMCID: PMC9393457 DOI: 10.4269/ajtmh.22-0061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/25/2021] [Indexed: 11/15/2022] Open
Abstract
Filarial infections caused by Loa loa and Mansonella perstans are a considerable public health burden in rural regions of Central Africa. Rapid diagnostic tools for the detection of microfilariae in the blood are needed. Field's stain is a rapid staining technique for microscopic slides originally established for malaria diagnostics. It requires less than 1 minute of staining compared with conventional staining protocols requiring at least 15 to 20 minutes for staining and could thus significantly accelerate diagnostics for human filariasis. Here we evaluated Field's stain as a rapid staining technique in comparison to Giemsa stain for the detection of microfilariae in peripheral blood. Blood smears were collected from 175 participants residing in the region of Lambaréné and Fougamou, Gabon. Each participant's samples were stained in parallel with Field's stain and conventional Giemsa stain. Slides were then microscopically assessed and compared for qualitative and quantitative results by a blinded assessor for the two endemic filarial blood pathogens M. perstans and L. loa. Field's stain shows excellent diagnostic performance characteristics for L. loa microfilariae compared with Giemsa staining. Concordance was favorable for M. perstans although lower than for L. loa. Field's stain offers a rapid alternative to Giemsa stain for detection of L. loa microfilariae in thick blood smears. This could help accelerate diagnostics of blood filarial pathogens in mass screening programs or resource constrained health care institutions with high patient load.
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Affiliation(s)
- Franck-A. Ekoka Mbassi
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, Libreville, Gabon
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Kirsten A. Eberhardt
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Sites Hamburg-Lübeck-Borstel-Riems
| | - Dorothea Ekoka Mbassi
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Sites Hamburg-Lübeck-Borstel-Riems
| | - Ayôla A. Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | | | - Marielle K. Bouyou-Akotet
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, Libreville, Gabon
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Sites Hamburg-Lübeck-Borstel-Riems
| | - Rella Zoleko-Manego
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical‚ Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Sites Hamburg-Lübeck-Borstel-Riems
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16
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Circulating IL-6, IL-10, and TNF-alpha and IL-10/IL-6 and IL-10/TNF-alpha ratio profiles of polyparasitized individuals in rural and urban areas of gabon. PLoS Negl Trop Dis 2022; 16:e0010308. [PMID: 35421083 PMCID: PMC9041759 DOI: 10.1371/journal.pntd.0010308] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 04/26/2022] [Accepted: 03/06/2022] [Indexed: 11/20/2022] Open
Abstract
Malaria, blood-borne filarial worms and intestinal parasites are all endemic in Gabon. This geographical co-distribution leads to polyparasitism and, consequently, the possibility of immune-mediated interactions among different parasite species. Intestinal protozoa and helminths could modulate antimalarial immunity, for example, thereby potentially increasing or reducing susceptibility to malaria. The aim of the study was to compare the cytokine levels and cytokine ratios according to parasitic profiles of the population to determine the potential role of co-endemic parasites in the malaria susceptibility of populations. Blood and stool samples were collected during cross-sectional surveys in five provinces of Gabon. Parasitological diagnosis was performed to detect plasmodial parasites, Loa loa, Mansonella perstans, intestinal helminths (STHs) and protozoan parasites. Nested PCR was used to detect submicroscopic plasmodial infection in individuals with negative blood smears. A cytometric bead array was used to quantify interleukin (IL)-6, IL-10 and tumour necrosis factor (TNF)-α in the plasma of subjects with different parasitological profiles. Median IL-6 and IL-10 levels and the median IL-10/TNF-α ratio were all significantly higher among individuals with Plasmodium (P.) falciparum infection than among other participants (p<0.0001). The median TNF-α level and IL-10/IL-6 ratio were higher in subjects with STHs (p = 0.09) and P. falciparum-intestinal protozoa co-infection (p = 0.04), respectively. IL-6 (r = -0.37; P<0.01) and IL-10 (r = -0.37; P<0.01) levels and the IL-10/TNF-α ratio (r = -0.36; P<0.01) correlated negatively with age. Among children under five years old, the IL-10/TNF-α and IL-10/IL-6 ratios were higher in those with intestinal protozoan infections than in uninfected children. The IL-10/TNF-α ratio was also higher in children aged 5–15 years and in adults harbouring blood-borne filariae than in their control counterparts, whereas the IL-10/IL-6 ratio was lower in those aged 5–15 years with filariae and intestinal parasites but higher in adults with intestinal parasitic infections. Asymptomatic malaria is associated with a strong polarization towards a regulatory immune response, presenting high circulating levels of IL-10. P. falciparum/intestinal protozoa co-infections were associated with an enhanced IL-10 response. Immunity against malaria could differ according to age and carriage of other parasites. Helminths and intestinal protozoa can play a role in the high susceptibility to malaria currently observed in some areas of Gabon, but further investigations are necessary. The current epidemiological transition of malaria observed in Gabon included, for example, a shift in the at-risk population from children aged less than 5 years old to older children aged 5–15 years. Another consequence was the increasing number of cases of infection among adults. In view of these findings, it is important to explain this phenomenon of epidemiological modification of malaria in Gabon. Intestinal parasites and blood filariasis are endemic in Gabon. These parasites are described to alter the malaria immune response and can be implicated in the susceptibility of individuals to malaria. In Gabon, malaria presents a heterogeneous repartition. Thus, in the present study, we investigated the role of co-endemic parasitosis in the alteration of the malarial immune response by comparing Th1 (IL-6 and TNF-α) and Th2/Treg (IL-10) cytokine production between mono- and co-parasitized individuals in many localities with different epidemiological patterns of malaria. Microscopic analyses and rapid antigenic tests were performed for malaria diagnosis. The nested PCR technique was used to demonstrate the submicroscopic parasitaemia of Plasmodium sp. Then, once groups with different parasitological profiles were constituted, IL-6, IL-10 and TNF-α levels were measured in the plasma of individuals. Th2/Th1 ratios, which can indicate the level of susceptibility of individuals to malaria, were calculated. We observed that there was no interaction between Plasmodium sp. and co-endemic parasites in the present study. However, the high Th2/Th1 cytokine ratio among patients with intestinal protozoa seems to suggest that these intestinal parasites could also play a role in susceptibility to malaria as they do for helminths.
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17
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Risch F, Ritter M, Hoerauf A, Hübner MP. Human filariasis-contributions of the Litomosoides sigmodontis and Acanthocheilonema viteae animal model. Parasitol Res 2021; 120:4125-4143. [PMID: 33547508 PMCID: PMC8599372 DOI: 10.1007/s00436-020-07026-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/20/2020] [Indexed: 12/16/2022]
Abstract
Filariae are vector-borne parasitic nematodes that are endemic worldwide, in tropical and subtropical regions. Important human filariae spp. include Onchocerca volvulus, Wuchereria bancrofti and Brugia spp., and Loa loa and Mansonella spp. causing onchocerciasis (river blindness), lymphatic filariasis (lymphedema and hydrocele), loiasis (eye worm), and mansonelliasis, respectively. It is estimated that over 1 billion individuals live in endemic regions where filarial diseases are a public health concern contributing to significant disability adjusted life years (DALYs). Thus, efforts to control and eliminate filarial diseases were already launched by the WHO in the 1970s, especially against lymphatic filariasis and onchocerciasis, and are mainly based on mass drug administration (MDA) of microfilaricidal drugs (ivermectin, diethylcarbamazine, albendazole) to filarial endemic areas accompanied with vector control strategies with the goal to reduce the transmission. With the United Nations Sustainable Development Goals (SDGs), it was decided to eliminate transmission of onchocerciasis and stop lymphatic filariasis as a public health problem by 2030. It was also requested that novel drugs and treatment strategies be developed. Mouse models provide an important platform for anti-filarial drug research in a preclinical setting. This review presents an overview about the Litomosoides sigmodontis and Acanthocheilonema viteae filarial mouse models and their role in immunological research as well as preclinical studies about novel anti-filarial drugs and treatment strategies.
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Affiliation(s)
- Frederic Risch
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany.
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany.
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18
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Sandri TL, Kreidenweiss A, Cavallo S, Weber D, Juhas S, Rodi M, Woldearegai TG, Gmeiner M, Veletzky L, Ramharter M, Tazemda-Kuitsouc GB, Matsiegui PB, Mordmüller B, Held J. Molecular Epidemiology of Mansonella Species in Gabon. J Infect Dis 2021; 223:287-296. [PMID: 33099649 DOI: 10.1093/infdis/jiaa670] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/20/2020] [Indexed: 01/04/2023] Open
Abstract
Mansonella perstans, a filarial nematode, infects large populations in Africa and Latin America. Recently, a potential new species, Mansonella sp "DEUX," was reported. Carriage of endosymbiotic Wolbachia opens treatment options for Mansonella infections. Within a cross-sectional study, we assessed the prevalence of filarial infections in 834 Gabonese individuals and the presence of the endosymbiont Wolbachia. Almost half of the participants (400/834 [48%]) were infected with filarial nematodes, with Mansonella sp "DEUX" being the most frequent (295/400 [74%]), followed by Loa loa (273/400 [68%]) and Mansonella perstans (82/400 [21%]). Being adult/elderly, male, and living in rural areas was associated with a higher risk of infection. Wolbachia carriage was confirmed in M. perstans and Mansonella sp "DEUX." In silico analysis revealed that Mansonella sp "DEUX" is not detected with currently published M. perstans-specific assays. Mansonella infections are highly prevalent in Gabon and might have been underreported, likely also beyond Gabon.
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Affiliation(s)
- Thaisa Lucas Sandri
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Laboratory of Molecular Immunopathology, Department of Clinical Pathology, Federal University of Paraná, Curitiba, Brazil
| | - Andrea Kreidenweiss
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Simon Cavallo
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - David Weber
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Sascha Juhas
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Miriam Rodi
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Tamirat Gebru Woldearegai
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Markus Gmeiner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Luzia Veletzky
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,German Center for Infection Research, partner site Tübingen, Tübingen, Germany
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19
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Nouatin O, Mengue JB, Dejon-Agobé JC, Fendel R, Ibáñez J, Ngoa UA, Edoa JR, Adégbité BR, Honkpéhédji YJ, Zinsou JF, Hounkpatin AB, Moutairou K, Homoet A, Esen M, Kreidenweiss A, Hoffman SL, Theisen M, Luty AJF, Lell B, Agnandji ST, Mombo-Ngoma G, Ramharter M, Kremsner P, Mordmüller B, Adegnika AA. Exploratory analysis of the effect of helminth infection on the immunogenicity and efficacy of the asexual blood-stage malaria vaccine candidate GMZ2. PLoS Negl Trop Dis 2021; 15:e0009361. [PMID: 34061838 PMCID: PMC8195366 DOI: 10.1371/journal.pntd.0009361] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 06/11/2021] [Accepted: 04/03/2021] [Indexed: 11/18/2022] Open
Abstract
Background Helminths can modulate the host immune response to Plasmodium falciparum and can therefore affect the risk of clinical malaria. We assessed here the effect of helminth infections on both the immunogenicity and efficacy of the GMZ2 malaria vaccine candidate, a recombinant protein consisting of conserved domains of GLURP and MSP3, two asexual blood-stage antigens of P. falciparum. Controlled human malaria infection (CHMI) was used to assess the efficacy of the vaccine. Methodology In a randomized, double-blind Phase I clinical trial, fifty, healthy, lifelong malaria-exposed adult volunteers received three doses of GMZ2 adjuvanted with either Cationic Adjuvant Formulation (CAF) 01 or Alhydrogel, or a control vaccine (Rabies) on days (D) 0, D28 and D56, followed by direct venous inoculation (DVI) of 3,200 P. falciparum sporozoites (PfSPZ Challenge) approximately 13 weeks after last vaccination to assess vaccine efficacy. Participants were followed-up on a daily basis with clinical examinations and thick blood smears to monitor P. falciparum parasitemia for 35 days. Malaria was defined as the presence of P. falciparum parasites in the blood associated with at least one symptom that can be associated to malaria over 35 days following DVI of PfSPZ Challenge. Soil-transmitted helminth (STH) infection was assessed by microscopy and by polymerase chain reaction (PCR) on stool, and Schistosoma infection was assessed by microscopy on urine. Participants were considered as infected if positive for any helminth either by PCR and/or microscopy at D0 and/or at D84 (Helm+) and were classified as mono-infection or co-infection. Total vaccine-specific IgG concentrations assessed on D84 were analysed as immunogenicity outcome. Main findings The helminth in mono-infection, particularly Schistosoma haematobium and STH were significantly associated with earlier malaria episodes following CHMI, while no association was found in case of coinfection. In further analyses, the anti-GMZ2 IgG concentration on D84 was significantly higher in the S. haematobium-infected and significantly lower in the Strongyloides stercoralis-infected groups, compared to helminth-negative volunteers. Interesting, in the absence of helminth infection, a high anti-GMZ2 IgG concentration on D84 was significantly associated with protection against malaria. Conclusions Our results suggest that helminth infection may reduce naturally acquired and vaccine-induced protection against malaria. Vaccine-specific antibody concentrations on D84 may be associated with protection in participants with no helminth infection. These results suggest that helminth infection affect malaria vaccine immunogenicity and efficacy in helminth endemic countries. Helminths, mainly because of their immune regulatory effects, are able to impact the response induced by vaccines. In the context of clinical trial designs that measure accrual of natural infections during follow up or outcome of controlled human malaria infection (CHMI), their effect on vaccine efficacy can be measured. Indeed, most of such clinical trials on malaria vaccine candidates conducted in Africa, especially where the prevalence of helminths is high, have shown a certain limit in their efficacy and immunogenicity, as compared to results observed in European and U.S volunteers. The present analysis assessed the effect of helminths on GMZ2, a malaria vaccine candidate. We found a high level of anti-GMZ2 antibodies among volunteers not infected with helminths and protected against CHMI, indicating efficacy of the candidate vaccine in this population. We found a species-dependent effect of helminths on the level of post-immunization GMZ2-specific IgG concentration, and an association of helminths with an early onset of malaria in CHMI. Our findings reveal that helminths are associated with immunogenicity and may decrease the protective effect of antibodies induced by vaccination. Helminth infection status shall be determined when measuring the immunogenicity and efficacy of malaria vaccine candidates in helminth endemic countries.
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Affiliation(s)
- Odilon Nouatin
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | | | - Jean Claude Dejon-Agobé
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Rolf Fendel
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Javier Ibáñez
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | | | | | - Bayodé Roméo Adégbité
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands.,Fondation pour la Recherche Scientifique, Cotonou, Bénin
| | - Yabo Josiane Honkpéhédji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Fondation pour la Recherche Scientifique, Cotonou, Bénin.,Department of Parasitology, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Jeannot Fréjus Zinsou
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Fondation pour la Recherche Scientifique, Cotonou, Bénin.,Department of Parasitology, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Aurore Bouyoukou Hounkpatin
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Kabirou Moutairou
- Département de Biochimie et de Biologie Cellulaire, Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Cotonou, Bénin
| | - Andreas Homoet
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Meral Esen
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Andrea Kreidenweiss
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | | | - Michael Theisen
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Adrian J F Luty
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance, Calavi, Bénin.,Université de Paris, MERIT, IRD, Paris, France
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I, Department of Medicine, University Medical Centre, Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I, Department of Medicine, University Medical Centre, Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Fondation pour la Recherche Scientifique, Cotonou, Bénin.,Department of Parasitology, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
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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. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.668641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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21
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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] [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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22
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Matthewman J, Manego RZ, Dimessa Mbadinga LB, Šinkovec H, Völker K, Akinosho M, Haedrich C, Tardif d’Hamonville J, Lell B, Adegnika AA, Ramharter M, Mombo-Ngoma G. A randomized controlled trial comparing the effectiveness of individual versus household treatment for Scabies in Lambaréné, Gabon. PLoS Negl Trop Dis 2020; 14:e0008423. [PMID: 32589632 PMCID: PMC7347237 DOI: 10.1371/journal.pntd.0008423] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/09/2020] [Accepted: 05/25/2020] [Indexed: 11/18/2022] Open
Abstract
Background It is unclear whether individual treatment of scabies is similarly effective compared to household treatment. This study compared these two treatment strategies with topical benzyl benzoate for treating scabies in Lambaréné, Gabon. Methods Participants presenting with uncomplicated scabies were randomized into either the Individual Treatment group, where only the affected participants received treatment, or the Household Treatment group, where all family members were treated in parallel to the affected participants regardless of signs and symptoms. The primary endpoint was clinical cure after 28 days; the secondary endpoint was the proportion of affected household members per household after 28 days. Results After 28 days, from a total of 79 participants assessed, 67% (n = 53) were clinically cured; 59% (20/34) in the Individual Treatment group and 73% (33/45) in the Household Treatment group. Participants in the Household Treatment group had about twice the odds of being cured (odds ratio 1.9, 95% confidence interval: 0.8–4.9; p = 0.17). For the secondary outcome, an effect of similar size was observed. Conclusions Our findings show that treating close contacts of persons affected by scabies may be beneficial to patients and contacts, however, the benefit was less pronounced than anticipated and further research is needed to definitively answer this question. Scabies is a skin disease caused by parasitic mites that burrow into the skin and cause itchiness and rash. Since these mites can be easily transmitted from person to person the disease is highly contagious. Many guidelines on the treatment of scabies recommend that all family members and close contacts of persons suffering from scabies should be treated alongside the affected person, in order to prevent the disease from spreading. However, there is only little evidence to be found in the medical literature on how well this practice works. We conducted a study in Lambaréné, Gabon and surrounding villages, where many cases of scabies occurred at the time, to answer this question. We found that, on average, those patients whose entire family was treated were more likely to be cured after 4 weeks, and that fewer of their family members were affected. However, the difference to patients whose families weren’t treated was smaller than expected, suggesting that larger studies are needed to definitively answer the question.
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Affiliation(s)
- Julian Matthewman
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, & I Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (JM); (GMN)
| | - Rella Zoleko Manego
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, & I Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Hana Šinkovec
- Center for Medical Statistics, Informatics and Intelligent Systems, Institute of Clinical Biometrics, Medical University of Vienna, Vienna, Austria
| | - Katrin Völker
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, & I Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Malik Akinosho
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | | | | | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Ayola Akim Adegnika
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, & I Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, & I Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (JM); (GMN)
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23
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Veletzky L, Hergeth J, Stelzl DR, Mischlinger J, Manego RZ, Mombo-Ngoma G, McCall MBB, Adegnika AA, Agnandji ST, Metzger WG, Matsiegui PB, Lagler H, Mordmüller B, Budke C, Ramharter M. Burden of disease in Gabon caused by loiasis: a cross-sectional survey. THE LANCET. INFECTIOUS DISEASES 2020; 20:1339-1346. [PMID: 32585133 DOI: 10.1016/s1473-3099(20)30256-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 03/12/2020] [Accepted: 03/23/2020] [Indexed: 11/13/2022]
Abstract
BACKGROUND Loiasis is a highly prevalent helminth infection found in distinct regions of sub-Saharan Africa. The disease has been considered to be of minor clinical significance, but this belief is being increasingly challenged by recent evidence. We aimed to prospectively quantify the overall burden of disease caused by loiasis in an endemic region of Gabon, using disability-adjusted life years (DALYs). METHODS We did a cross-sectional survey during 2017 and 2018 in rural Gabon. Volunteers underwent diagnostic tests for loiasis and were given a standardised questionnaire on symptoms. Participants reporting eye worm migration or harbouring Loa loa microfilariae were defined as loiasis positive. Morbidity-based DALYs associated with loiasis were estimated for the rural population of Gabon. FINDINGS Between Sept 1, 2017 and May 31, 2018, 1235 participants residing in 38 villages in the Gabonese departments of Tsamba-Magotsi and Ogooué et des Lacs were screened. 626 (50·8%) of 1232 eligible participants had loiasis. 520 (42·2%) of 1232 participants reported eye worm migration. 478 (93·9%) of 509 individuals with eye worm migration also reported associated pain, and 397 (78·6%) of 505 reported vision disturbances. After correcting for age and sex, loiasis was significantly associated with a variety of symptoms, including transient painful oedema (adjusted odds ratio 1·76 [95% CI 1·37-2·26]) and arthralgia (1·30 [1·01-1·69]). Application of attributable fractions of correlating symptoms resulted in 412·9 (95% CI 273·9-567·7) morbidity-based DALYs per 100 000 people in rural Gabon. INTERPRETATION Loiasis, with the pathognomonic sign of eye worm migration, appears to not be benign, but severely impeding to affected individuals. Furthermore, loiasis is associated with substantial morbidity, comparable to that of other neglected tropical parasitic diseases. These findings call for reconsideration of L loa as a relevant pathogen in affected populations, with a need for more concerted research and control of these infections. FUNDING Federal Ministry of Science, Research and Economy of Austria, and the European Union.
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Affiliation(s)
- Luzia Veletzky
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Lambaréné Medical Research Centre, Lambaréné, Gabon; Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | | | | | - Johannes Mischlinger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Rella Zoleko Manego
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Lambaréné Medical Research Centre, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Lambaréné Medical Research Centre, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | - Matthew B B McCall
- Lambaréné Medical Research Centre, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany; Radboud University Medical Centre, Department of Medical Microbiology, Nijmegen, Netherlands
| | - Ayôla A Adegnika
- Lambaréné Medical Research Centre, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | - Selidji T Agnandji
- Lambaréné Medical Research Centre, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | - Wolfram G Metzger
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | | | - Heimo Lagler
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Centre for Infection Research, Tübingen, Germany
| | - Christine Budke
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Lambaréné Medical Research Centre, Lambaréné, Gabon.
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Abbate JL, Becquart P, Leroy E, Ezenwa VO, Roche B. Exposure to Ebola Virus and Risk for Infection with Malaria Parasites, Rural Gabon. Emerg Infect Dis 2020; 26:229-237. [PMID: 31829919 PMCID: PMC6986822 DOI: 10.3201/eid2602.181120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
An association between malaria and risk for death among patients with Ebola virus disease has suggested within-host interactions between Plasmodium falciparum parasites and Ebola virus. To determine whether such an interaction might also influence the probability of acquiring either infection, we used a large snapshot surveillance study from rural Gabon to test if past exposure to Ebola virus is associated with current infection with Plasmodium spp. during nonepidemic conditions. We found a strong positive association, on population and individual levels, between seropositivity for antibodies against Ebola virus and the presence of Plasmodium parasites in the blood. According to a multiple regression model accounting for other key variables, antibodies against Ebola virus emerged as the strongest individual-level risk factor for acquiring malaria. Our results suggest that within-host interactions between malaria parasites and Ebola virus may underlie epidemiologic associations.
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Buell KG, Whittaker C, Chesnais CB, Jewell PD, Pion SDS, Walker M, Basáñez MG, Boussinesq M. Atypical Clinical Manifestations of Loiasis and Their Relevance for Endemic Populations. Open Forum Infect Dis 2019; 6:ofz417. [PMID: 31696139 PMCID: PMC6824532 DOI: 10.1093/ofid/ofz417] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/08/2019] [Indexed: 01/02/2023] Open
Abstract
Background Loiasis is mostly considered a relatively benign infection when compared with other filarial and parasitic diseases, with Calabar swellings and eyeworm being the most common signs. Yet, there are numerous reports in the literature of more serious sequelae. Establishing the relationship between infection and disease is a crucial first step toward estimating the burden of loiasis. Methods We conducted a systematic review of case reports containing 329 individuals and detailing clinical manifestations of loiasis with a focus on nonclassical, atypical presentations. Results Results indicate a high proportion (47%) of atypical presentations in the case reports identified, encompassing a wide range of cardiac, respiratory, gastrointestinal, renal, neurological, ophthalmological, and dermatological pathologies. Individuals with high microfilarial densities and residing in an endemic country were at greater risk of suffering from atypical manifestations. Conclusions Our findings have important implications for understanding the clinical spectrum of conditions associated with Loa loa infection, which extends well beyond the classical eyeworm and Calabar swellings. As case reports may overestimate the true rate of atypical manifestations in endemic populations, large-scale, longitudinal clinico-epidemiological studies will be required to refine our estimates and demonstrate causality between loiasis and the breadth of clinical manifestations reported. Even if the rates of atypical presentations were found to be lower, given that residents of loiasis-endemic areas are both numerous and the group most at risk of severe atypical manifestations, our conclusions support the recognition of loiasis as a significant public health burden across Central Africa.
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Affiliation(s)
- Kevin G Buell
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Faculty of Medicine (St Mary's Campus), Imperial College London, London, UK
| | - Charles Whittaker
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Faculty of Medicine (St Mary's Campus), Imperial College London, London, UK
| | - Cédric B Chesnais
- Institut de Recherche pour le Développement (IRD), UMI 233-INSERM U1175-Montpellier University, Montpellier, France
| | - Paul D Jewell
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Faculty of Medicine (St Mary's Campus), Imperial College London, London, UK
| | - Sébastien D S Pion
- Institut de Recherche pour le Développement (IRD), UMI 233-INSERM U1175-Montpellier University, Montpellier, France
| | - Martin Walker
- Department of Pathobiology and Population Sciences, London Centre for Neglected Tropical Disease Research, Royal Veterinary College, Hatfield, UK
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis, Faculty of Medicine (St Mary's Campus), Imperial College London, London, UK
| | - Michel Boussinesq
- Institut de Recherche pour le Développement (IRD), UMI 233-INSERM U1175-Montpellier University, Montpellier, France
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Mischlinger J, Veletzky L, Tazemda-Kuitsouc GB, Pitzinger P, Matsegui PB, Gmeiner M, Lagler H, Gebru T, Held J, Mordmüller B, Ramharter M. Behavioural and clinical predictors for Loiasis. J Glob Health 2018; 8:010413. [PMID: 29497506 PMCID: PMC5827628 DOI: 10.7189/jogh.08.010413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Loiasis is a vector-borne disease in Central and West Africa. While there is still uncertainty to what extent loiasis is responsible for population morbidity, individuals having both loiasis and onchocerciasis have a high risk of fatal encephalopathy when treatment (ie, ivermectin) for onchocerciasis is given. Therefore it is current policy that communities of high loiasis-burden are excluded from mass drug administration programmes of ivermectin. To address this treatment gap we present diagnostic scores, based on clinical and behavioural predictors that may help to rapidly identify sub-groups with loiasis within high-burden communities. Methods A cross-sectional survey was performed in the province of la Ngounie, Gabon between December 2015 and Februrary 2016 and 947 participants of all ages were recruited. Clinical parameters and behavioural exposure factors were ascertained by questionnaire-based interviews. Parasitological analysis of blood samples was performed for L. loa detection. Diagnostic scores consisting of clinical and behavioural factors were modelled to predict loiasis in sub-groups residing in endemic regions. Results Increasing sylvan exposure was identified as important risk factor for loiasis with adjusted odds ratios of 5.1 (95% confidence interval CI 2.6-9.9) for occasional forest exposure, 11.1 (95% CI 5.4-22.6) for frequent forest exposure and 25.7 (95% CI 12.5-52.9) for intensive forest exposure. Individuals with loiasis were 7.7 (95% CI 5.4-11.0) times more likely to report recurrent pruritus than those without loiasis. Reporting of regular daily exposure to the deep rain forest and recurrent pruritus was 9-fold (positive likelihood ratio 9.18; 95% CI: 6.39-13.18) more prevalent in individuals with loiasis than in controls. Concordantly, the absence of regular weekly forest exposure was associated with extremely low disease-likelihood (negative likelihood ratio 0.09; 95% CI 0.05-0.16). Conclusions These composite scores may serve as a simple tool to rapidly identify both those most and those least at risk of disease and may simplify loiasis control activities as well as screening procedures for studies on loiasis. Further, they may aid policy-makers to tailor the delivery of ivermectin mass drug administration for onchocerciasis control programmes more effectively and safely in regions of high loiasis-burden.
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Affiliation(s)
- Johannes Mischlinger
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany.,Bernhard Nocht Hospital for Tropical Diseases, Bernhard Nocht Institute for Tropical Medicine and University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Luzia Veletzky
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Bernhard Nocht Hospital for Tropical Diseases, Bernhard Nocht Institute for Tropical Medicine and University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Paul Pitzinger
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Pierre B Matsegui
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
| | - Markus Gmeiner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Heimo Lagler
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Tamirat Gebru
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Jana Held
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - Michael Ramharter
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, and German Center for Infection Research, partner site Tübingen, Tübingen, Germany.,Bernhard Nocht Hospital for Tropical Diseases, Bernhard Nocht Institute for Tropical Medicine and University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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27
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Njouendou AJ, Fombad FF, O'Neill M, Zofou D, Nutting C, Ndongmo PC, Kengne-Ouafo AJ, Geary TG, Mackenzie CD, Wanji S. Heterogeneity in the in vitro susceptibility of Loa loa microfilariae to drugs commonly used in parasitological infections. Parasit Vectors 2018; 11:223. [PMID: 29615094 PMCID: PMC5883330 DOI: 10.1186/s13071-018-2799-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/15/2018] [Indexed: 01/10/2023] Open
Abstract
Background Co-infection with loiasis remains a potential problem in control programs targeting filarial infections. The effects of many anti-parasitic drugs often administered to Loa loa infected people are not well documented. This study compared the in vitro activity of several of these drugs on the viability of L. loa microfilariae (mf). Methods Human strain L. loa mf were isolated from baboon blood using iso-osmotic Percoll gradient, and cultured in RPMI 1640/10% FBS with antimalarial drugs (mefloquine, amodiaquine, artesunate, chloroquine and quinine), anthelmintics (ivermectin, praziquantel, flubendazole and its reduced and hydrolyzed metabolites), two potential trypanocidal agents (fexinidazole and Scynexis-7158) and the anticancer drug imatinib. The drug concentrations used varied between 0.156 μg/ml and 10 μg/ml. Mf motility (CR50 = 50% immotility) and a metabolic viability assay (MTT) were used to assess the effects of these drugs on the parasites. Results Mf in control cultures showed only a slight reduction in motility after 5 days of culture. Active inhibition of Loa loa motility was seen with mefloquine and amodiaquine (CR50 values of 3.87 and 4.05 μg/ml, respectively), immobilizing > 90% mf within the first 24 hours: mefloquine killed the mf after 24 hours of culture at concentrations ≥ 5 μg/ml. SCYX-7158 also induced a concentration-dependent reduction in mf motility, with > 50% reduction in mf motility seen after 5 days at 10 μg/ml. The anticancer drug imatinib reduced mf motility at 10 μg/ml from the first day of incubation to 55% by day 5, and the reduction in motility was concentration-dependent. Praziquantel and fexinidazole were inactive, and FLBZ and its metabolites, as well as ivermectin at concentrations > 5 μg/ml, had very minimal effects on mf motility over the first 4 days of culture. Conclusions The considerable action of the anti-malarial drugs mefloquine and amodiaquine on Loa mf in vitro highlights the possibility of repurposing the existing anti-infectious agents for the development of drugs against loiasis. The heterogeneity in the activity of anti-parasitic agents on Loa loa mf supports the need for further investigation using animal models of loiasis. Electronic supplementary material The online version of this article (10.1186/s13071-018-2799-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Abdel J Njouendou
- Parasites and Vectors Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Fanny F Fombad
- Parasites and Vectors Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Maeghan O'Neill
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Denis Zofou
- Biotechnology unit, Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Chuck Nutting
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - Patrick C Ndongmo
- Parasites and Vectors Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Arnaud J Kengne-Ouafo
- Parasites and Vectors Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Timothy G Geary
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Charles D Mackenzie
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI, 48824, USA.,Filariasis Programmes Support Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Samuel Wanji
- Parasites and Vectors Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.
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28
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Whittaker C, Walker M, Pion SD, Chesnais CB, Boussinesq M, Basáñez MG. The Population Biology and Transmission Dynamics of Loa loa. Trends Parasitol 2018; 34:335-350. [DOI: 10.1016/j.pt.2017.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/10/2017] [Accepted: 12/11/2017] [Indexed: 11/27/2022]
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M’bondoukwé NP, Kendjo E, Mawili-Mboumba DP, Koumba Lengongo JV, Offouga Mbouoronde C, Nkoghe D, Touré F, Bouyou-Akotet MK. Prevalence of and risk factors for malaria, filariasis, and intestinal parasites as single infections or co-infections in different settlements of Gabon, Central Africa. Infect Dis Poverty 2018; 7:6. [PMID: 29378644 PMCID: PMC5789590 DOI: 10.1186/s40249-017-0381-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 12/13/2017] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Malaria, filariasis, and intestinal parasitic infections (IPIs) are common and frequently overlap in developing countries. The prevalence and predictors of these infections were investigated in three different settlements (rural, semi-urban, and urban) of Gabon. METHODS During cross-sectional surveys performed from September 2013 to June 2014, 451 individuals were interviewed. In addition, blood and stool samples were analysed for the presence of Plasmodium, filarial roundworm, intestinal protozoan, and helminth infections. RESULTS Intestinal parasitic infections (61.1%), including intestinal protozoa (56.7%) and soil-transmitted helminths (STHs) (22.2%), predominated, whereas Plasmodium falciparum (18.8%), Loa loa (4.7%), and Mansonella perstans (1.1%) were less prevalent. Filariasis and STHs were mainly found in rural settlements, whereas a higher plasmodial infection prevalence rate was observed in the periurban area. The most common IPI was blastocystosis (48.6%), followed by ascaridiasis (13.7%), trichuriasis (11.8%), amoebiasis (9.3%), giardiasis (4.8%), and strongyloidiasis (3.7%). Hookworm was detected in one adult from rural Dienga. Adults had a higher prevalence of Blastocystis hominis and STHs, whereas Giardia duodenalis was more frequently observed among children aged below 5 years (P < 0.01). The polyparasitism rate was 41.5%, with 7.0% Plasmodium-IPIs and 1.8% Plasmodium-STH co-infections. The multivariate analysis showed that living in a suburban area, belonging to the age group of 5-15 years, having none or a secondary education, or having an open body water close to home were significant risk factors for malaria (P ≤ 0.01). For STH infections, identified risk factors were drinking untreated water and living in a rural area (P ≤ 0.04). No significant predictors were identified for IPIs and malaria-IPI co-infection. CONCLUSIONS This study reports a high prevalence of IPIs and intestinal protozoa, but a low rate of malaria-IPI co-infections in the study sites. Improvements in the living conditions of the population such as adequate water supply and proper health education and sanitation should be integrated into control strategies for malaria, STHs, and IPIs.
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Affiliation(s)
- Noé Patrick M’bondoukwé
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
| | - Eric Kendjo
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
| | - Denise Patricia Mawili-Mboumba
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
| | - Jeanne Vanessa Koumba Lengongo
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
| | - Christelle Offouga Mbouoronde
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
| | - Dieudonné Nkoghe
- International Center for Medical Research of Franceville, Franceville, Gabon
| | - Fousseyni Touré
- International Center for Medical Research of Franceville, Franceville, Gabon
| | - Marielle Karine Bouyou-Akotet
- Department of Parasitology-Mycology, Faculty of Medicine, University of Health Sciences, P.O. Box 4009, Libreville, Gabon
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30
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Manego RZ, Mombo-Ngoma G, Witte M, Held J, Gmeiner M, Gebru T, Tazemda B, Mischlinger J, Groger M, Lell B, Adegnika AA, Agnandji ST, Kremsner PG, Mordmüller B, Ramharter M, Matsiegui PB. Demography, maternal health and the epidemiology of malaria and other major infectious diseases in the rural department Tsamba-Magotsi, Ngounie Province, in central African Gabon. BMC Public Health 2017; 17:130. [PMID: 28129759 PMCID: PMC5273856 DOI: 10.1186/s12889-017-4045-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 01/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sub-Saharan Africa is undergoing an epidemiological transition from a predominance of infectious diseases to non-communicable and lifestyle related conditions. However, the pace of this transition and the pattern of disease epidemiology are uneven between affluent urban and rural poor populations. To address this question for a remote rural region located in the central African rainforest region of Gabon, this study was conducted to assess reasons for health care attendance and to characterize the epidemiology of malaria and other major infectious diseases for the department of Tsamba Magotsi. METHODS Major causes for health care attendance were collected from local hospital records. Cross sectional population based surveys were performed for the assessment of local malaria epidemiology. Pregnant women attending antenatal care services were surveyed as a sentinel population for the characterization of chronic viral and parasitic infections in the community. RESULTS Infectious diseases were responsible for 71% (7469) of a total of 10,580 consultations at the formal health care sector in 2010. Overall, malaria - defined by clinical syndrome - remained the most frequent cause for health care attendance. A cross sectional malaria survey in 840 asymptomatic individuals residing in Tsamba Magotsi resulted in a Plasmodium spp. infection prevalence of 37%. The infection rate in 2-10 year old asymptomatic children - a standard measure for malaria endemicity - was 46% (100 of 217) with P. falciparum as predominant species (79%). Infection with other plasmodial species (P. ovale and P. malariae) presented most commonly as coinfections (23.2%). Prevalence of HIV, HBV, and syphilis were 6.2, 7.3, and 2.5%, respectively, in cross-sectional assessments of antenatal care visits of pregnant women. Urogenital schistosomiasis and the filarial pathogens Loa loa and Mansonella perstans are highly prevalent chronic parasitic infections affecting the local population. CONCLUSIONS Despite major improvements in the accessibility of Tsamba Magotsi over the past decade the epidemiological transition does not appear to have majorly changed on the spectrum of diseases in this rural Gabonese population. The high prevalence of Plasmodium infection indicates a high burden of malaria related morbidity. Infectious diseases remain one of the most important health issues and further research activities in the field of tropical medicine and infectious diseases could help improve health care for the local population.
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Affiliation(s)
- R Zoleko Manego
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - G Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Département de Parasitologie-Mycologie, Université des Sciences de La Santé, Libreville, Gabon
| | - M Witte
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - J Held
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Deutsches Zentrum für Infektionsforschung (DZIF), Standort, Tübingen, Germany
| | - M Gmeiner
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Deutsches Zentrum für Infektionsforschung (DZIF), Standort, Tübingen, Germany
| | - T Gebru
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Deutsches Zentrum für Infektionsforschung (DZIF), Standort, Tübingen, Germany
| | - B Tazemda
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
| | - J Mischlinger
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - M Groger
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - B Lell
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - A A Adegnika
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - S T Agnandji
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - P G Kremsner
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany
| | - B Mordmüller
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Deutsches Zentrum für Infektionsforschung (DZIF), Standort, Tübingen, Germany
| | - M Ramharter
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon. .,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany. .,Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.
| | - P B Matsiegui
- Centre de Recherches Médicales de Lambaréné , Lambaréné, Gabon.,Institut für Tropenmedizin, University of Tübingen, 72074, Tübingen, Germany.,Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
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31
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Debrah LB, Nausch N, Opoku VS, Owusu W, Mubarik Y, Berko DA, Wanji S, Layland LE, Hoerauf A, Jacobsen M, Debrah AY, Phillips RO. Epidemiology of Mansonella perstans in the middle belt of Ghana. Parasit Vectors 2017; 10:15. [PMID: 28061905 PMCID: PMC5219801 DOI: 10.1186/s13071-016-1960-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 12/28/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mansonellosis was first reported in Ghana by Awadzi in the 1990s. Co-infections of Mansonella perstans have also been reported in a small cohort of patients with Buruli ulcer and their contacts. However, no study has assessed the exact prevalence of the disease in a larger study population. This study therefore aimed to find out the prevalence of M. perstans infection in some districts in Ghana and to determine the diversity of Culicoides that could be potential vectors for transmission. METHODS From each participant screened in the Asante Akim North (Ashanti Region), Sene West and Atebubu Amantin (Brong Ahafo Region) districts, a total of 70 μl of finger prick blood was collected for assessment of M. perstans microfilariae. Centre for Disease Control (CDC) light traps as well as the Human Landing Catch (HLC) method were used to assess the species diversity of Culicoides present in the study communities. RESULTS From 2,247 participants, an overall prevalence of 32% was recorded although up to 75% prevalence was demonstrated in some of the communities. Culicoides inornatipennis was the only species of Culicoides caught with the HLC method. By contrast, C. imicola (47%), C. neavei (25%) and C. schultzei (15%) were caught by the CDC light trap method. A wide diversity of other Culicoides spp. was also identified but correlation was only found between the prevalence of C. inornatipennis and M. perstans during the dry season. CONCLUSIONS Here we demonstrate for the first time that M. perstans is highly prevalent in three districts in Ghana. We found a wide spectrum of Culicoides spp. Culicoides inornatipennis was the most anthropophilic and is therefore likely to be the species responsible for transmission of infection but formal proof has yet to be obtained. TRIAL REGISTRATION NCT02281643 . Registered October 26, 2014. 'Retrospectively registered'. TRIAL REGISTRY ClinicalTrials.gov.
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Affiliation(s)
- Linda Batsa Debrah
- Kumasi Centre for Collaborative Research into Tropical Medicine (KCCR), Kumasi, Ghana. .,Department of Clinical Microbiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Norman Nausch
- Department of General Pediatrics, Neonatology, and Pediatric Cardiology, University Children's Hospital, Duesseldorf, Germany
| | - Vera Serwaa Opoku
- Kumasi Centre for Collaborative Research into Tropical Medicine (KCCR), Kumasi, Ghana
| | - Wellington Owusu
- Kumasi Centre for Collaborative Research into Tropical Medicine (KCCR), Kumasi, Ghana
| | - Yusif Mubarik
- Kumasi Centre for Collaborative Research into Tropical Medicine (KCCR), Kumasi, Ghana
| | - Daniel Antwi Berko
- Kumasi Centre for Collaborative Research into Tropical Medicine (KCCR), Kumasi, Ghana
| | - Samuel Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Laura E Layland
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Marc Jacobsen
- Department of General Pediatrics, Neonatology, and Pediatric Cardiology, University Children's Hospital, Duesseldorf, Germany
| | - Alexander Yaw Debrah
- Faculty of Allied Health Sciences of Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Richard O Phillips
- Department of Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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Ateba-Ngoa U, Jones S, Zinsou JF, Honkpehedji J, Adegnika AA, Agobe JCD, Massinga-Loembe M, Mordmüller B, Bousema T, Yazdanbakhsh M. Associations Between Helminth Infections, Plasmodium falciparum Parasite Carriage and Antibody Responses to Sexual and Asexual Stage Malarial Antigens. Am J Trop Med Hyg 2016; 95:394-400. [PMID: 27273645 DOI: 10.4269/ajtmh.15-0703] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 12/28/2015] [Indexed: 12/28/2022] Open
Abstract
Infections with helminths and Plasmodium spp. overlap in their geographical distribution. It has been postulated that helminth infections may influence malarial transmission by altering Plasmodium falciparum gametocytogenesis. This cross-sectional study assessed the effect of helminth infections on P. falciparum gametocyte carriage and on humoral immune responses to sexual stage antigens in Gabon. Schistosoma haematobium and filarial infections as well as P. falciparum asexual forms and gametocyte carriage were determined. The antibody responses measured were to sexual (Pfs230, Pfs48/45) and asexual P. falciparum antigens (AMA1, MSP1, and GLURP). A total of 287 subjects were included. The prevalence of microscopically detectable P. falciparum asexual parasites was higher in S. haematobium-infected subjects in comparison to their uninfected counterparts (47% versus 26%, P = 0.003), but this was not different when filarial infections were considered. Plasmodium falciparum gametocyte carriage was similar between Schistosoma- or filaria-infected and uninfected subjects. We observed a significant decrease of Pfs48/45 immunoglobulin G titer in S. haematobium-infected subjects (P = 0.037), whereas no difference was seen for Pfs230 antibody titer, nor for antibodies to AMA1, MSP1, or GLURP. Our findings suggest an effect of S. haematobium on antibody responses to some P. falciparum gametocyte antigens that may have consequences for transmission-blocking immunity.
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Affiliation(s)
- Ulysse Ateba-Ngoa
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands. Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.
| | - Sophie Jones
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jeannot Fréjus Zinsou
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Josiane Honkpehedji
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Ayola Akim Adegnika
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands. Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Jean-Claude Dejon Agobe
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Marguerite Massinga-Loembe
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Teun Bousema
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom. Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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Wanji S, Tayong DB, Layland LE, Datchoua Poutcheu FR, Ndongmo WPC, Kengne-Ouafo JA, Ritter M, Amvongo-Adjia N, Fombad FF, Njeshi CN, Nkwescheu AS, Enyong PA, Hoerauf A. Update on the distribution of Mansonella perstans in the southern part of Cameroon: influence of ecological factors and mass drug administration with ivermectin. Parasit Vectors 2016; 9:311. [PMID: 27245442 PMCID: PMC4886396 DOI: 10.1186/s13071-016-1595-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/17/2016] [Indexed: 11/10/2022] Open
Abstract
Background Mansonellosis remains one of the most neglected of tropical diseases and its current distribution in the entire forest block of southern Cameroon is unknown. In order to address this issue, we have surveyed the distribution of Mansonella perstans in different bioecological zones and in addition, elucidated the influence of multiple rounds of ivermectin (IVM) based mass drug administration (MDA). Methods A mixed design was used. Between 2000 and 2014, both cross-sectional and longitudinal surveys were carried out in 137 communities selected from 12 health districts belonging to five main bioecological zones of the southern part of Cameroon. The zones comprised of grassland savanna (GS), mosaic forest savanna (MFS), forested savanna (FS), deciduous equatorial rainforest (DERF) and the dense humid equatorial rainforest (DHERF). The survey was carried out in some areas with no treatment history as well as those currently under IVM MDA. Individuals within the participatory communities were screened for the presence of M. perstans microfilariae (mf) in peripheral blood by the calibrated thick film method to determine both prevalence and geometric mean intensities at the community level. Results Apart from sporadic cases in savanna areas, distribution of M. perstans was strongly linked to the equatorial rainforest zones. Before CDTI, the highest mean prevalence (70.0 %) and intensity (17,382.2 mf/ml) were obtained in communities in Mamfes’ DHERF areas followed by communities in the DHERF zone of Lolodorf (53.8 % and 7,814.8 mf/ml, respectively). A longitudinal survey in Mamfe further showed that M. perstans infections had reduced by 34.5 % in DERF (P < 0.001) but not DHERF zones after ten years of IVM MDA. Further data from the cross-sectional study revealed that there was a decrease in prevalence in DHERF zones only after ten years of MDA. In DERF zones however, the infection was relatively lower after four years of MDA. Conclusions The distribution of M. perstans in the southern part of Cameroon varies with bioecological zones and IVM MDA history. The zones with high prevalence and intensities lie in forested areas while those with low endemicity are in the savanna areas. MDA with ivermectin induced significant reduction in the endemicity of mansonellosis in the decidious equatorial rainforest. In contrast, the prevalence and intensity remained relatively high and stable in the dense humid equatorial rainforest zones even after a decade of mass drug administration with ivermectin. Since it is known that M. perstans down-regulates host's immune system, the findings from this work would be useful in designing studies to understand the impact of M. perstans on host immune response to vaccination and co-infection with other pathogens such as Mycobacterium spp. and Plasmodium spp. in areas of contrasting endemicities. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1595-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- 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.
| | - Dizzle Bita Tayong
- 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
| | - Laura E Layland
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), partner site, Bonn-Cologne, Bonn, Germany
| | - Fabrice R Datchoua Poutcheu
- 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
| | - Winston Patrick Chounna Ndongmo
- 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
| | - Jonas Arnaud Kengne-Ouafo
- 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 of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), partner site, Bonn-Cologne, Bonn, Germany
| | | | - 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
| | - Charity Nya Njeshi
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Armand Seraphin Nkwescheu
- Scientific Networks and Ethics Promotion, Division of Health Operations Research, Ministry of Public Health, Yaoundé, Republic of Cameroon
| | - Peter A 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 of Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), partner site, Bonn-Cologne, Bonn, Germany
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Drame PM, Montavon C, Pion SD, Kubofcik J, Fay MP, Nutman TB. Molecular Epidemiology of Blood-Borne Human Parasites in a Loa loa-, Mansonella perstans-, and Plasmodium falciparum-Endemic Region of Cameroon. Am J Trop Med Hyg 2016; 94:1301-1308. [PMID: 27044568 PMCID: PMC4889748 DOI: 10.4269/ajtmh.15-0746] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/23/2015] [Indexed: 12/17/2022] Open
Abstract
The study of the interactions among parasites within their hosts is crucial to the understanding of epidemiology of disease and for the design of effective control strategies. We have conducted an assessment of infections with Loa loa, Mansonella perstans, Wuchereria bancrofti, and Plasmodium falciparum in eastern Cameroon using a highly sensitive and specific quantitative polymerase chain reaction assay using archived dried whole blood spots. The resident population (N = 1,085) was parasitized with M. perstans (76%), L. loa (39%), and P. falciparum (33%), but not with W. bancrofti Compared with single infections (40.1%), coinfection was more common (48.8%): 21.0% had L. loa-M. perstans (Ll(+)/Mp(+)/Pf(-)), 2.7% had L. loa-P. falciparum (Ll(+)/Pf(+)/Mp(-)), 15.1% had M. perstans-P. falciparum (Mp(+)/Pf(+)/Ll(-)), and 10.0% had L. loa-M. perstans-P. falciparum (Ll(+)/Mp(+)/Pf(+)). Interestingly, those with all three infections (Ll(+)/Mp(+)/Pf(+)) had significantly higher L. loa microfilaria (mf) counts than either single Ll(+) (P = 0.004) or double Ll(+)/Mp(+) (P = 0.024) infected individuals. Of those infected with L. loa, the mean estimated counts of L. loa mf varied based on location and were positively correlated with estimated intensities of M. perstans mf. Finally, at a community level, heavy L. loa infections were concentrated in a few individuals whereby they were likely the major reservoir for infection.
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Affiliation(s)
- Papa M. Drame
- *Address correspondence to Papa M. Drame, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Drive, Bethesda, MD 20892. E-mail:
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Ecological Drivers of Mansonella perstans Infection in Uganda and Patterns of Co-endemicity with Lymphatic Filariasis and Malaria. PLoS Negl Trop Dis 2016; 10:e0004319. [PMID: 26793972 PMCID: PMC4721671 DOI: 10.1371/journal.pntd.0004319] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/02/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mansonella perstans is a widespread, but relatively unknown human filarial parasite transmitted by Culicoides biting midges. Although it is found in many parts of sub-Saharan Africa, only few studies have been carried out to deepen the understanding of its ecology, epidemiology, and health consequences. Hence, knowledge about ecological drivers of the vector and parasite distribution, integral to develop spatially explicit models for disease prevention, control, and elimination strategies, is limited. METHODOLOGY We analyzed data from a comprehensive nationwide survey of M. perstans infection conducted in 76 schools across Uganda in 2000-2003, to identify environmental drivers. A suite of Bayesian geostatistical regression models was fitted, and the best fitting model based on the deviance information criterion was utilized to predict M. perstans infection risk for all of Uganda. Additionally, we investigated co-infection rates and co-distribution with Wuchereria bancrofti and Plasmodium spp. infections observed at the same survey by mapping geographically overlapping areas. PRINCIPAL FINDINGS Several bioclimatic factors were significantly associated with M. perstans infection levels. A spatial Bayesian regression model showed the best fit, with diurnal temperature range, normalized difference vegetation index, and cattle densities identified as significant covariates. This model was employed to predict M. perstans infection risk at non-sampled locations. The level of co-infection with W. bancrofti was low (0.3%), due to limited geographic overlap. However, where the two infections did overlap geographically, a positive association was found. CONCLUSIONS/SIGNIFICANCE This study presents the first geostatistical risk map for M. perstans in Uganda. We confirmed a widespread distribution of M. perstans, and identified important potential drivers of risk. The results provide new insight about the ecologic preferences of this otherwise poorly known filarial parasite and its Culicoides vector species in Uganda, which might be relevant for other settings in sub-Saharan Africa.
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Mansonella, including a Potential New Species, as Common Parasites in Children in Gabon. PLoS Negl Trop Dis 2015; 9:e0004155. [PMID: 26484866 PMCID: PMC4618925 DOI: 10.1371/journal.pntd.0004155] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/21/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Like other tropical African countries, Gabon is afflicted by many parasitic diseases, including filariases such as loiasis and mansonellosis. This study aimed to assess the prevalence of these two filarial diseases in febrile and afebrile children using quantitative real-time PCR and standard PCR assays coupled with sequencing. METHODOLOGY/PRINCIPAL FINDINGS DNA from blood specimens of 1,418 Gabonese children (1,258 febrile and 160 afebrile) were analyzed. Overall, filarial DNA was detected in 95 (6.7%) children, including 67 positive for M. perstans (4.7%), which was the most common. M. perstans was detected in 61/1,258 febrile children (4.8%) and 6/160 afebrile children (3.8%, P = 0.6). Its prevalence increased statistically with age: 3.5%, 7.7% and 10.6% in children aged ≤ 5, 6-10 and 11-15 years, respectively. M. perstans prevalence was significantly higher in Koulamoutou and Lastourville (12% and 10.5%, respectively) than in Franceville and Fougamou (2.6% and 2.4%, respectively). Loa loa was detected in seven febrile children including one co-infection with M. perstans. Finally, 21 filarial DNA positive were negative for M. perstans and Loa loa, but ITS sequencing could be performed for 12 and allowed the identification of a potential new species of Mansonella provisionally called "DEUX". Mansonella sp. "DEUX" was detected only in febrile children. CONCLUSIONS/SIGNIFICANCE Further study should be performed to characterize Mansonella sp. "DEUX" and evaluate the clinical significance of mansonellosis in humans.
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The relationship between microfilaraemic and amicrofilaraemic loiasis involving co-infection with Mansonella perstans and clinical symptoms in an exposed population from Gabon. J Helminthol 2015; 90:469-75. [DOI: 10.1017/s0022149x15000607] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThe relationship between the frequency of loiasis objective symptoms and microfilaraemic or amicrofilaraemic infection was assessed in 1148 exposed patients also infected, or not, with Mansonella perstans. Filarial infections were detected by direct microscopy, leucoconcentration and serology, with prevalence values of 39.5% Loa loa, 5.6% M. perstans and 3.4% co-infection with both filarial species. Amicrofilaraemic or occult loiasis (OL) predominated among L. loa-infected individuals, with a prevalence of 58.2%. Hypermicrofilaraemia (>8000 microfilariae (mf)/ml) was found in 18.4% of L. loa microfilaraemic patients, with 25.7% of them harbouring more than 30,000 mf/ml. Up to 34% of patients with OL showed evidence of Calabar swelling, compared with 26.3% of microfilaraemic patients (P= 0.03). Overall 5.3% of patients presented with adult worm migration across the eye, representing 16.3% of microfilaraemic individuals and 11.4% of amicrofilaraemic patients (P= 0.13). This symptom was similarly found in patients with more than 30,000 mf/ml (22%), those with microfilaraemia between 8 and 30,000 mf/ml (15.4%) and also in individuals with low or without microfilaraemia (16.1%) (P= 0.7). Five (14.3%) hypermicrofilaraemic patients did not present any L. loa-specific objective symptoms, as well as all the patients with single M. perstans infection. The presence of adult eye worm migration as a strong predictor of high microfilaraemia density would obscure the real burden of L. loa hypermicrofilaraemia in exposed individuals. For epidemiological purposes and control strategies, the mapping of L. loa in endemic areas should also take into account the group of patients with occult loiasis.
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Janssen S, Hermans S, Knap M, Moekotte A, Rossatanga EG, Adegnika AA, Bélard S, Hänscheid T, Grobusch MP. Impact of Anti-Retroviral Treatment and Cotrimoxazole Prophylaxis on Helminth Infections in HIV-Infected Patients in Lambaréné, Gabon. PLoS Negl Trop Dis 2015; 9:e0003769. [PMID: 25993501 PMCID: PMC4439024 DOI: 10.1371/journal.pntd.0003769] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/17/2015] [Indexed: 12/31/2022] Open
Abstract
Background Foci of the HIV epidemic and helminthic infections largely overlap geographically. Treatment options for helminth infections are limited, and there is a paucity of drug-development research in this area. Limited evidence suggests that antiretroviral therapy (ART) reduces prevalence of helminth infections in HIV-infected individuals. We investigated whether ART exposure and cotrimoxazole preventive therapy (CTX-P) is associated with a reduced prevalence of helminth infections. Methodology and Principal Findings This cross-sectional study was conducted at a primary HIV-clinic in Lambaréné, Gabon. HIV-infected adults who were ART-naïve or exposed to ART for at least 3 months submitted one blood sample and stool and urine samples on 3 consecutive days. Outcome was helminth infection with intestinal helminths, Schistosoma haematobium, Loa loa or Mansonella perstans. Multivariable logistic regression was used to assess associations between ART or CTX-P and helminth infection. In total, 408 patients were enrolled. Helminth infection was common (77/252 [30.5%]). Filarial infections were most prevalent (55/310 [17.7%]), followed by infection with intestinal helminths (35/296 [11.8%]) and S. haematobium (19/323 [5.9%]). Patients on CTX-P had a reduced risk of Loa loa microfilaremia (adjusted odds ratio (aOR) 0.47, 95% CI 0.23-0.97, P = 0.04), also in the subgroup of patients on ART (aOR 0.36, 95% CI 0.13-0.96, P = 0.04). There was no effect of ART exposure on helminth infection prevalence. Conclusions/Significance CTX-P use was associated with a decreased risk of Loa loa infection, suggesting an anthelminthic effect of antifolate drugs. No relation between ART use and helminth infections was established. The geographical distribution of helminth infections, which are highly prevalent in many areas, overlaps considerably with regions of high HIV sero-prevalence. The highest burden of infection is found in resource-poor settings, making it unattractive for the pharmaceutical industry to invest. Limited available treatment options and drug-resistance are increasing problems for soil-transmitted helminths, whereas for some other helminth infections, such as for the blood-dwelling microfilariae, effective and safe treatment options are still far from being optimal. Limited evidence suggests antihelminthic effects of antiretroviral therapy (ART) in HIV-infected individuals. We aimed to investigate whether ART or cotrimoxazole preventive treatment (CTX-P) reduces prevalence of helminth infection in HIV-infected individuals attending a primary HIV clinic in a semi-rural area in Gabon. The most important finding of our study was that the use of CTX-P was associated with a reduced prevalence of Loa loa microfilaremia. ART use was not associated with a reduced prevalence of helminth infections. Additional studies are needed to assess the effects of CTX on helminth infections, as this might be a promising safe and effective drug adding to the limited repertoire of anthelminthic drugs.
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Affiliation(s)
- Saskia Janssen
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Centre de Traitement Ambulatoire (CTA), Lambaréné, Gabon
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Clinical Infectious Diseases Research Initiative, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- * E-mail:
| | - Sabine Hermans
- Desmond Tutu HIV Centre, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Department of Global Health, Amsterdam Institute for Global Health and Development, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Internal Medicine, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Martijn Knap
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Alma Moekotte
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | | | - Akim A. Adegnika
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Sabine Bélard
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin, Berlin, Germany
| | - Thomas Hänscheid
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Instituto de Microbiologia, Faculdade de Medicina de Lisboa, Lisbon, Portugal
| | - Martin P. Grobusch
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Clinical Infectious Diseases Research Initiative, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Department of Global Health, Amsterdam Institute for Global Health and Development, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Mombo-Ngoma G, Mackanga JR, Basra A, Capan M, Manego RZ, Adegnika AA, Lötsch F, Yazdanbakhsh M, González R, Menendez C, Mabika B, Matsiegui PB, Kremsner PG, Ramharter M. Loa loa Infection in Pregnant Women, Gabon. Emerg Infect Dis 2015; 21:899-901. [PMID: 25897819 PMCID: PMC4412224 DOI: 10.3201/eid2105.141471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Co-endemicity of loiasis and onchocerciasis in rain forest communities in southwestern Nigeria. PLoS Negl Trop Dis 2015; 9:e0003633. [PMID: 25812086 PMCID: PMC4374772 DOI: 10.1371/journal.pntd.0003633] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 02/20/2015] [Indexed: 11/19/2022] Open
Abstract
Background Loiasis is currently receiving attention as a disease of public health importance because of the possibility of increased risk of developing neurologic serious adverse event following mass ivermectin treatment against onchocerciasis in individual co-infected with Onchocerca volvulus and Loa loa. Methodology/Principal Findings Rapid assessment procedure for loiasis (RAPLOA) was conducted in 12 communities covering the 3 senatorial districts of Osun State, Nigeria. A total of 960 people were interviewed for history of eye worm using the WHO guidelines for rapid assessment. The survey confirmed the presence of loiasis in all the 12 communities with 4 in Osun East/Ife south senatorial district being at high risk with a prevalence of over 40%. Based on the RAPLOA results, communities within Osun East/Ife south senatorial district were selected for microfilaraemic assessment of L. loa and O. volvulus. A total of 1115 and 1091 individuals were screened for L. loa and O. volvulus microfilaria worms respectively. 160 (14.3%) had L. loa microfilaria detected in their blood with 8 (5.0%) individuals having L. loa loads above 8000 mf/ml. 166 (15.2%) subjects had O. volvulus microfilaria (range 4-504 mf/ml) detected in their skin snip. 30 (2.69%) subjects were co-infected with both L. loa and O. volvulus. There was a significant variation in the prevalence (2.1% to 33.3%) of onchocerciasis in the communities studied (p = 0.001). Five (41.7%) of the studied communities had a prevalence that is equal to or greater than 20%. Conclusions/Significance Low prevalence of onchocerciasis and loiasis co-infection in this study suggests that loiasis may not pose a serious epidemiological threat to the continuous distribution and sustainability of ivermectin for the treatment of onchocerciasis. Evaluation of the interruption of onchocerciasis transmissions in this region using all the indicators set forth by WHO is therefore suggested. Loiasis recently emerged as a disease of public health importance because of the risk of rare severe adverse events (SAEs) associated with the rapid killing of Loa loa microfilariae in heavily parasitized individuals following ivermectin treatment. for onchocerciasis. The possibility of developing these SAEs has been slowing down the control of onchocerciasis in some endemic communities. Based on information available at the Osun State Ministry of Health, the detailed geographic distribution of L. loa in Osun State is still awaiting elucidation. The results of this study revealed an overlap in geographic distribution of loasis and onchocerciasis in many communities in Osun State. The overall Community Microfilaria Load (CMFL) for L. loa was below the threshold level of endemicity that could be associated with the risk of SAEs after ivermectin treatment. Most individuals with slightly high L. loa microfilaria are either O. volvulus microfilaria free or have very low microfilaria load. The low prevalence of co-infection of both diseases in the study area is an indication that loiasis may not pose any serious epidemiological threat to the distribution and sustainability of ivermectin in the treatment of onchocerciaisis.
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Ateba-Ngoa U, Mombo-Ngoma G, Zettlmeissl E, van der Vlugt LEPM, de Jong S, Matsiegui PB, Ramharter M, Kremsner PG, Yazdanbakhsh M, Adegnika AA. CD4+CD25hiFOXP3+ cells in cord blood of neonates born from filaria infected mother are negatively associated with CD4+Tbet+ and CD4+RORγt+ T cells. PLoS One 2014; 9:e114630. [PMID: 25531674 PMCID: PMC4273973 DOI: 10.1371/journal.pone.0114630] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/11/2014] [Indexed: 11/18/2022] Open
Abstract
Background Children who have been exposed in utero to maternal filarial infection are immunologically less responsive to filarial antigens, have less pathology, and are more susceptible to acquire infection than offspring of uninfected mothers. Moreover children from filaria infected mothers have been shown to be less responsive to vaccination as a consequence of an impairment of their immune response. However, it is not well known how in utero exposure to parasite antigens affects cellular immune responses. Methodology Here, 30 pregnant women were examined for the presence of microfilaria of Loa loa and Mansonella perstans in peripheral blood. At delivery, cord blood mononuclear cells (CBMC) were obtained and the CD4+T cells were phenotyped by expression of the transcription factors Tbet, RORγt, and FOXP3. Results No significant difference was observed between newborns from infected versus uninfected mothers in the frequencies of total CD4+T cells and CD4+T cells subsets including CD4+Tbet+, CD4+RORγt+ T and CD4+CD25hiFOXP3+ T cells. However, there was a negative association between CD4+CD25hiFOXP3+T cells and CD4+Tbet+ as well as CD4+RORγt+ T cells in the infected group only (B = −0.242, P = 0.002; B = −0.178, P = 0.013 respectively). Conclusion Our results suggest that filarial infection during pregnancy leads to an expansion of functionally active regulatory T cells that keep TH1 and TH17 in check.
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Affiliation(s)
- Ulysse Ateba-Ngoa
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
- Département de Parasitologie-Mycologie, Université des Sciences de la Santé, BP 4009, Libreville, Gabon
| | - Eva Zettlmeissl
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
| | | | - Sanne de Jong
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
| | - Pierre-Blaise Matsiegui
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria
| | - Peter G. Kremsner
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
| | - Maria Yazdanbakhsh
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
| | - Ayola Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, BP 118, Lambaréné, Gabon
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2 2333 ZA Leiden, The Netherlands
- Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27 D-72074 Tübingen, Germany
- * E-mail:
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Ateba Ngoa U, Zinsou JF, Kassa RFK, Ngoune Feugap E, Honkpehedji YJ, Massinga-Loembe M, Kenguele Moundounga H, Nkoma Mouima AM, Mbenkep LH, Wammes LJ, Mbow M, Kruize Y, Mombo-Ngoma G, Bouyoukou Hounkpatin AL, Dejon Agobe JC, Saadou I, Lell B, Smits H, Kremsner PG, Yazdanbakhsh M, Adegnika AA. Assessment of the effect of Schistosoma haematobium co infection on malaria parasites and immune responses in rural populations in Gabon: study protocol. SPRINGERPLUS 2014; 3:388. [PMID: 25120947 PMCID: PMC4128953 DOI: 10.1186/2193-1801-3-388] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 07/15/2014] [Indexed: 02/05/2023]
Abstract
Background Malaria and helminth co infection are common in tropical and subtropical areas where they affect the life of millions of people. While both helminth and malaria parasites have immunomodulatory activities, little is known about the consequence of co-infections on malaria antigen specific immune responses. Method/Design This study will be conducted in two rural areas of the Moyen Ogooué province in Gabon, endemic for both Plasmodium falciparum and Schistosoma haematobium infections. Participants, 5 to 50 years old, will be enrolled and grouped according to their infection status. S. haematobium and malaria parasites will be detected, demographic and clinical data will be recorded and blood will be collected for hematological as well as for immunological assays. The level of antibody specific to Plasmodium falciparum blood stage and gametocyte antigens will be measured using ELISA. PBMC will be isolated for phenotyping of different T cell subsets ex vivo by flow cytometry and for culture and cytokine response assessment. Discussion We will provide a comprehensive picture of the interaction between schistosomes and malaria parasites which co-localize in peripheral blood. We will test the hypothesis that schistosome infection has an impact on specific humoral as well as on cellular immune responses to malaria antigens.
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Affiliation(s)
- Ulysse Ateba Ngoa
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany ; Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Jeannot Fréjus Zinsou
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Roland Fabrice Kassa Kassa
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Eliane Ngoune Feugap
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Yabo Josiane Honkpehedji
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Marguerite Massinga-Loembe
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany ; Faculté de Médecine, Université des Sciences de la Santé de Libreville, BP: 4009, Libreville, Gabon
| | - Hilaire Kenguele Moundounga
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Anne Marie Nkoma Mouima
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Lima Honorine Mbenkep
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Linda Judith Wammes
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Moustapha Mbow
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands ; Immunology Unit of the Laboratory of Bacteriology and Virology of Aristide Le Dantec Teaching Hospital, 30 Avenue Pasteur, BP 7325, Dakar, Senegal ; Institute of Tropical Medicine of Antwerp, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Yvonne Kruize
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany ; Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands ; Faculté de Médecine, Université des Sciences de la Santé de Libreville, BP: 4009, Libreville, Gabon
| | - Aurore Larissa Bouyoukou Hounkpatin
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Jean Claude Dejon Agobe
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Issifou Saadou
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Hermelijn Smits
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Peter Gottfried Kremsner
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Ayola Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, BP: 118, Lambaréné, Gabon ; Institut für Tropenmedizin, Universität Tübingen, Wilhelmstraβe 27, D-72074 Tübingen, Germany ; Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
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Gehringer C, Kreidenweiss A, Flamen A, Antony JS, Grobusch MP, Bélard S. Molecular Evidence ofWolbachiaEndosymbiosis inMansonella perstansin Gabon, Central Africa. J Infect Dis 2014; 210:1633-8. [DOI: 10.1093/infdis/jiu320] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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van der Vlugt LEPM, Zinsou JF, Ozir-Fazalalikhan A, Kremsner PG, Yazdanbakhsh M, Adegnika AA, Smits HH. Interleukin 10 (IL-10)–Producing CD1dhi Regulatory B Cells From Schistosoma Haematobium–Infected Individuals Induce IL-10–Positive T Cells and Suppress Effector T-Cell Cytokines. J Infect Dis 2014; 210:1207-16. [DOI: 10.1093/infdis/jiu257] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Loop-mediated isothermal amplification for rapid and semiquantitative detection of Loa loa infection. J Clin Microbiol 2014; 52:2071-7. [PMID: 24696020 DOI: 10.1128/jcm.00525-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rapid and accurate tests are currently needed to identify individuals with high levels of Loa loa microfilaria (mf), so that these individuals may be excluded from mass ivermectin administration campaigns against onchocerciasis and lymphatic filariasis being conducted in areas where Onchocerca volvulus, Wuchereria bancrofti, and L. loa are coendemic. To address this need, colorimetric loop-mediated isothermal amplification (LAMP) assays targeting the L. loa-specific gene sequences LLMF72 and LLMF342 were developed for the detection and quantification of L. loa microfilaremia. Both LAMP assays were highly specific (100%) for L. loa infection compared to the absence of infection or infection with related filarial pathogens. The LLMF72-based LAMP assay showed greater analytic sensitivity (limit of detection, 0.1 pg/ml of genomic DNA [gDNA] and/or 5 mf/ml) than the LLMF342-based LAMP assay (10 pg/ml of gDNA and/or 50 mf/ml), and its analytic sensitivity was similar to that of LLMF72-based quantitative PCR (qPCR). A high level of correlation was observed between microfilaria counts as determined by LLMF72-based qPCR and time to positivity by the LAMP assay, and performance measures of sensitivity, specificity, and positive and negative predictive values were similar for both assays when applied to field-collected clinical samples. By simply varying the run time, the LAMP assay was able to accurately distinguish individuals at risk for serious adverse events (SAEs) after exposure to ivermectin, using thresholds of >5,000 mf/ml and >30,000 mf/ml as indicators of increasing levels of risk. In summary, LLMF72 LAMP represents a new molecular diagnostic tool that is readily applicable as a point-of-care method for L. loa microfilarial detection and quantification in resource-limited countries where L. loa infection is endemic.
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Metzger WG, Mordmüller B. Loa loa—does it deserve to be neglected? THE LANCET. INFECTIOUS DISEASES 2014; 14:353-7. [DOI: 10.1016/s1473-3099(13)70263-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Filaria zoogeography in Africa: ecology, competitive exclusion, and public health relevance. Trends Parasitol 2014; 30:163-9. [PMID: 24636357 DOI: 10.1016/j.pt.2014.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 02/04/2014] [Accepted: 02/09/2014] [Indexed: 11/20/2022]
Abstract
Six species of filariae infect humans in sub-Saharan Africa. We hypothesise that these nematodes are able to polyparasitise human hosts by having successfully, through competitive exclusion, adapted to distinct niches. Despite inhabiting the same host, adult stages reside in different tissue sites. Microfilariae of some species exhibit temporal separation by reaching peak levels in the blood at specific times of day. Spatial and temporal distributions in microfilaria location are exploited by the vector feeding-behaviour whereas adult survival is enhanced by occupying exclusive 'ecological' niches of the body. We present specific examples to demonstrate this concept, which is not only important from the biological aspect but important in the context of elimination programmes.
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Bouyou-Akotet M, Moussavou Boussougou M, Ovono-Abessolo F, Owono-Medang M, Kombila M. Influence of Mansonella perstans microfilaraemia on total IgE levels in Gabonese patients co-infected with Loa loa. Acta Trop 2014; 131:11-5. [PMID: 24280145 DOI: 10.1016/j.actatropica.2013.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 11/25/2022]
Abstract
Mansonella (M.) perstans filariasis is widely found in Africa, including Gabon where Loa loa is also endemic. This study reports the total IgE titres according to different bioclinical forms of single or co-infection with L. loa and M. perstans in 138 patients and 20 healthy controls. The median parasite density was significantly higher in cases of loiasis. IgE titres were higher in patients with microscopic dual-infection and in the group of patients with occult loiasis plus M. perstans microfilaraemia (8425 [5292-20,679]KUI/L and 6304 [1045-10,326]KUI/L, respectively), compared to individuals with either microfilaraemic Loa loa (3368 [1414-7074]KUI/L) or Mansonella (4370 [1478-7334]KUI/L) single infections (p<0.01). IgE levels were positively correlated with M. perstans microfilaraemia (rho=0.27; p<0.01). Compared to single infections, dual M. perstans-L. loa infection induces very high total IgE titres. Studies correlating IgE titres and clinical symptoms are needed to confirm the involvement of this immunoglobulin in the pathological processes during filariasis.
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Senghor B, Diallo A, Sylla SN, Doucouré S, Ndiath MO, Gaayeb L, Djuikwo-Teukeng FF, Bâ CT, Sokhna C. Prevalence and intensity of urinary schistosomiasis among school children in the district of Niakhar, region of Fatick, Senegal. Parasit Vectors 2014; 7:5. [PMID: 24387599 PMCID: PMC3882112 DOI: 10.1186/1756-3305-7-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 12/23/2013] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Urinary schistosomiasis is a parasitic disease that exists in all regions of Senegal. It is a major public health issue in this country. This study was carried out to determine the prevalence and intensity of this parasitosis in 12 villages of Niakhar (Fatick, Senegal). METHODS A total of 210 schoolchildren, aged 7 to 15 years, were enrolled in this study, and urine samples were examined for Schistosoma haematobium eggs using a standard urine filtration technique. RESULTS Of these children, 121 (57.6%) were found to be infected with a mean geometric count of 185 eggs per 10 ml of urine. The disease was present in all surveyed villages, and the prevalence ranged from 14.3% to 92.8%. The prevalence of infection was significantly correlated with increasing age and was higher in boys. Infection intensity was significantly higher in boys but did not significantly differ with age. Significant relationships between i) water contact or access to running water and ii) the prevalence or intensity of urinary schistosomiasis were also noted. CONCLUSIONS The district of Niakhar is endemic for urinary schistosomiasis, with a high intensity of infection. A control program to decrease the prevalence and intensity should be implemented in this area to improve community health.
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Affiliation(s)
- Bruno Senghor
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
- Département de Biologie Animale, Université Cheikh Anta Diop de Dakar, BP 5005 Dakar, Senegal
| | - Aldiouma Diallo
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
| | - Seydou N Sylla
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
- Université Gaston Berger de Saint Louis, UFR Sciences Appliquées et Technologies, BP 234 Saint Louis, Senegal
| | - Souleymane Doucouré
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
| | - Mamadou O Ndiath
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
| | - Lobna Gaayeb
- EPLS Biomedical Research Center, Saint-Louis, Senegal
| | | | - Cheikh T Bâ
- Département de Biologie Animale, Université Cheikh Anta Diop de Dakar, BP 5005 Dakar, Senegal
| | - Cheikh Sokhna
- Institut de Recherche pour le Développement, UMR 198 (URMITE), Campus International de Hann, IRD, BP 1386, CP 18524 Dakar, Senegal
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