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Amambo GN, Fombad FF, Chounna Ndongmo PW, Abong RA, Njouendou AJ, Beng AA, Nji TM, Esum ME, Fru-Cho J, Manuel R, Kebede D, Enyong PI, Hoerauf A, Koudou B, Bockarie M, Wanji S. Impact of repeated mass ivermectin administration using a community directed approach on L. loa infection in Chrysops silacea of the rain forest and forest savanna of Cameroon. Parasite Epidemiol Control 2024; 25:e00343. [PMID: 38405181 PMCID: PMC10884510 DOI: 10.1016/j.parepi.2024.e00343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/22/2023] [Accepted: 02/06/2024] [Indexed: 02/27/2024] Open
Abstract
Background Loiasis is an endemic filarial infection in the rainforest zone of West and Central Africa. Repeated annual community-directed treatment with ivermectin (CDTI) delivered for several years to control onchocerciasis has been shown to reduce the prevalence and intensity of Loiasis in some Loa loa-Onchocerca volvulus co-endemic areas. However, the impact of these multiple rounds of CDTI on entomological indicators of loiasis transmission is not known, and was therefore assessed in this study in areas with contrasting histories of CDTI. Methods The study was conducted in the East, North-west and South-west 1 CDTI project sites of Cameroon. Two communities per CDTI project were selected for fly collection and dissection. Ivermectin treatment coverage was documented in these areas, and this was correlated to Chrysops infection and infective rates. A total of 7029 female Chrysops were collected from 6 communities of the 3 CDTI projects (East, North-west, and South-west 1) and from 2 communities in a non-CDTI district (East). Results Chrysops biting densities and parous rates were significantly reduced in the North-west and South-west sites post-CDTI, while in the East, biting densities were similar in non-CDTI and CDTI sites, with higher parous rates observed in the non-CDTI site. Infection and infective rates in the East non-CDTI site were 4.4% and 1.8% respectively, as compared to 3.3% and 1.3% in the CDTI site after 10 ivermectin rounds (there were no baseline data for the latter). In the North-west site, significant reductions in Chrysops infection and infective rates from 10.2% and 4.2% respectively, to 3.5% and 1.2 (after 9 rounds of ivermectin treatment), were recorded following CDTI. In the South-west, infection rate significantly increased from 1.74% to 2.8% and infective rate remained statistically unchanged after 14 rounds of CDTI (0.45% - 0.40%). Similar trends in Mean Head L3 were observed except in the East site where this indicator was similar in both CDTI and control sites. Only in the North-west site did monthly transmission potentials decrease significantly. Conclusion This study demonstrated that the impact of repeated annual treatment with ivermectin for the control of onchocerciasis using community directed delivery approach on the entomological indicators of loiasis varies with bioecological zones. Community directed treatment with ivermectin induced a significant reduction in the entomological indicators of loiasis in the North-West project site which lies in forest savanna area. A non-significant decrease was observed in the East project site and in contrast, a significant increase was observed in the South-West 1 project site which both lies in the rainforest zones.
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Affiliation(s)
- Glory N. Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- Centre for Neglected Tropical Diseases (Incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- German Center for Infection Research (DZIF), Partner site Bonn-Cologne, Bonn, Germany
| | - Fanny F. Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Patrick W. Chounna Ndongmo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Department of Biomedical Science, Faculty of Health Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Theobald Mue Nji
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
- Department of Sociology and Anthropology, Faculty of Social and Management Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Jerome Fru-Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Ritter Manuel
- Institute of Medical Microbiology, Immunology, and Parasitology, University Hospital Bonn, Germany
| | - Deribe Kebede
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton BN1 9PX, United Kingdom
- School of Public Health, College of Health Sciences, Addis Ababa University, Ethiopia
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology, and Parasitology, University Hospital Bonn, Germany
- German Center for Infection Research (DZIF), Partner site Bonn-Cologne, Bonn, Germany
| | - Benjamin Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Moses Bockarie
- Centre for Neglected Tropical Diseases (Incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Res1earch Foundation for Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
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2
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Ambe LA, Limunga E, Mbah CE, Adela N, Eric N, Ngoe M, Sone B, Lochnit G, Tachu JB, Wanji S, Taubert A, Hermosilla C, Kamena F. Identification and Characterization of Onchocerca volvulus Heat Shock Protein 70 ( OvHSP70) as Novel Diagnostic Marker of Onchocerciasis in Human Urine. Pathogens 2024; 13:293. [PMID: 38668248 PMCID: PMC11053476 DOI: 10.3390/pathogens13040293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 04/29/2024] Open
Abstract
Despite several decades of mass drug administration and elimination-related activities, human onchocerciasis still represents a major parasitic threat in endemic regions. Among the challenges encountered by the elimination program is the lack of a suitable diagnostic tool that is accurate and non-invasive. Currently used methods are either invasive or not suitable for monitoring large numbers of patients. Herein, we describe the identification and characterization of Onchocerca volvulus heat shock protein 70 (OvHSP70) as a novel diagnostic biomarker for human onchocerciasis, which can directly be detected in urine samples of infected patients. This nematode-specific antigen was identified through LC-MS after differential SDS-PAGE using urine-derived protein extracts from O. volvulus-infected patients in Cameroon. Polyclonal antibodies generated in rabbits after cloning and expression of OvHSP70 in Escherichia coli reliably differentiated between urine samples from infected- and uninfected patients in a hypoendemic area of human onchocerciasis. These results provide an excellent basis for further development of a non-invasive and scalable diagnostic assay for human onchocerciasis using urine samples. Such a urine-based diagnostic assay will be of major importance for the elimination program of human onchcerciasis in endemic countries.
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Affiliation(s)
- Lum Abienwi Ambe
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Elisabeth Limunga
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Clarisse Engowei Mbah
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Ngwewondo Adela
- Centre for Research on Health and Priority Pathologies, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaounde P.O. Box 13033, Cameroon; (C.E.M.); (N.A.)
| | - Ndumu Eric
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Martha Ngoe
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Bertrand Sone
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Günter Lochnit
- Protein Analytics, Institute of Biochemistry, Faculty of Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany;
| | - Julius Babila Tachu
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon;
- Research Foundation in Tropical Disease and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Anja Taubert
- Biomedical Research Center Seltersberg (BFS), Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (A.T.); (C.H.)
| | - Carlos Hermosilla
- Biomedical Research Center Seltersberg (BFS), Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (A.T.); (C.H.)
| | - Faustin Kamena
- Laboratory for Molecular Parasitology, Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon; (E.L.); (N.E.); (M.N.); (B.S.); (J.B.T.)
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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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Maddren R, Phillips A, Rayment Gomez S, Forbes K, Collyer BS, Kura K, Anderson R. Individual longitudinal compliance to neglected tropical disease mass drug administration programmes, a systematic review. PLoS Negl Trop Dis 2023; 17:e0010853. [PMID: 37459369 PMCID: PMC10374057 DOI: 10.1371/journal.pntd.0010853] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 07/27/2023] [Accepted: 06/05/2023] [Indexed: 07/28/2023] Open
Abstract
Repeated distribution of preventative chemotherapy (PC) by mass drug administration forms the mainstay of transmission control for five of the 20 recognised neglected tropical diseases (NTDs); soil-transmitted helminths, schistosomiasis, lymphatic filariasis, onchocerciasis and trachoma. The efficiency of such programmes is reliant upon participants swallowing the offered treatment consistently at each round. This is measured by compliance, defined as the proportion of eligible participants swallowing treatment. Individually linked longitudinal compliance data is important for assessing the potential impact of MDA-based control programmes, yet this accurate monitoring is rarely implemented in those for NTDs. Longitudinal compliance data reported by control programmes globally for the five (PC)-NTDs since 2016 is examined, focusing on key associations of compliance with age and gender. PubMed and Web of Science was searched in January 2022 for articles written in English and Spanish, and the subsequent extraction adhered to PRISMA guidelines. Study title screening was aided by Rayyan, a machine learning software package. Studies were considered for inclusion if primary compliance data was recorded for more than one time point, in a population larger than 100 participants. All data analysis was conducted in R. A total of 89 studies were identified containing compliance data, 57 were longitudinal studies, of which 25 reported individually linked data reported by varying methods. The association of increasing age with the degree of systematic treatment was commonly reported. The review is limited by the paucity of data published on this topic. The varying and overlapping terminologies used to describe coverage (receiving treatment) and compliance (swallowing treatment) is reviewed. Consequently, it is recommended that WHO considers clearly defining the terms for coverage, compliance, and longitudinal compliance which are currently contradictory across their NTD treatment guidelines. This review is registered with PROSPERO (number: CRD42022301991).
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Affiliation(s)
- Rosie Maddren
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
| | - Anna Phillips
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
- FHI 360, Durham, North Carolina, United States of America
| | - Santiago Rayment Gomez
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
| | - Kathryn Forbes
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
| | - Benjamin S Collyer
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
| | - Klodeta Kura
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
| | - Roy Anderson
- Department of Infectious Disease Epidemiology, Imperial College London, Saint Mary's Campus, Norfolk Place, London, United Kingdom
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Risch F, Scheunemann JF, Reichwald JJ, Lenz B, Ehrens A, Gal J, Fercoq F, Koschel M, Fendler M, Hoerauf A, Martin C, Hübner MP. The efficacy of the benzimidazoles oxfendazole and flubendazole against Litomosoides sigmodontis is dependent on the adaptive and innate immune system. Front Microbiol 2023; 14:1213143. [PMID: 37440891 PMCID: PMC10335397 DOI: 10.3389/fmicb.2023.1213143] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023] Open
Abstract
Filarial nematodes can cause debilitating diseases such as lymphatic filariasis and onchocerciasis. Oxfendazole (OXF) is one promising macrofilaricidal candidate with improved oral availability compared to flubendazole (FBZ), and OXF is currently under preparation for phase 2 clinical trials in filariasis patients. This study aimed to investigate the immune system's role during treatment with OXF and FBZ and explore the potential to boost the treatment efficacy via stimulation of the immune system. Wild type (WT) BALB/c, eosinophil-deficient ΔdblGata1, IL-4r/IL-5-/-, antibody-deficient μMT and B-, T-, NK-cell and ILC-deficient Rag2/IL-2rγ-/- mice were infected with the rodent filaria Litomosoides sigmodontis and treated with an optimal and suboptimal regimen of OXF and FBZ for up to 5 days. In the second part, WT mice were treated for 2-3 days with a combination of OXF and IL-4, IL-5, or IL-33. Treatment of WT mice reduced the adult worm burden by up to 94% (OXF) and 100% (FBZ) compared to vehicle controls. In contrast, treatment efficacy was lower in all immunodeficient strains with a reduction of up to 90% (OXF) and 75% (FBZ) for ΔdblGata1, 50 and 92% for IL-4r/IL-5-/-, 64 and 78% for μMT or 0% for Rag2/IL-2rγ-/- mice. The effect of OXF on microfilariae and embryogenesis displayed a similar pattern, while FBZ's ability to prevent microfilaremia was independent of the host's immune status. Furthermore, flow cytometric analysis revealed strain-and treatment-specific immunological changes. The efficacy of a shortened 3-day treatment of OXF (-33% adult worms vs. vehicle) could be boosted to a 91% worm burden reduction via combination with IL-5, but not IL-4 or IL-33. Our results suggest that various components of the immune system support the filaricidal effect of benzimidazoles in vivo and present an opportunity to boost treatment efficacy.
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Affiliation(s)
- Frederic Risch
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Johanna F. Scheunemann
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Julia J. Reichwald
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Benjamin Lenz
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Alexandra Ehrens
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Joséphine Gal
- Unité Molécules de Communication et Adaptation des Microorganismes, Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Paris, France
| | - Frédéric Fercoq
- Unité Molécules de Communication et Adaptation des Microorganismes, Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Paris, France
| | - Marianne Koschel
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Martina Fendler
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Coralie Martin
- Unité Molécules de Communication et Adaptation des Microorganismes, Sorbonne Université, Muséum national d’Histoire naturelle, CNRS, Paris, France
| | - Marc P. Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
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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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7
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Schluth CG, Standley CJ, Bansal S, Carlson CJ. Spatial parasitology and the unmapped human helminthiases. Parasitology 2023; 150:1-9. [PMID: 36632014 PMCID: PMC10090474 DOI: 10.1017/s0031182023000045] [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: 08/28/2022] [Revised: 12/29/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023]
Abstract
Helminthiases are a class of neglected tropical diseases that affect at least 1 billion people worldwide, with a disproportionate impact on resource-poor areas with limited disease surveillance. Geospatial methods can offer valuable insights into the burden of these infections, particularly given that many are subject to strong ecological influences on the environmental, vector-borne or zoonotic stages of their life cycle. In this study, we screened 6829 abstracts and analysed 485 studies that use maps to document, infer or predict transmission patterns for over 200 species of parasitic worms. We found that quantitative mapping methods are increasingly used in medical parasitology, drawing on One Health surveillance data from the community scale to model geographic distributions and burdens up to the regional or global scale. However, we found that the vast majority of the human helminthiases may be entirely unmapped, with research effort focused disproportionately on a half-dozen infections that are targeted by mass drug administration programmes. Entire regions were also surprisingly under-represented in the literature, particularly southern Asia and the Neotropics. We conclude by proposing a shortlist of possible priorities for future research, including several neglected helminthiases with a burden that may be underestimated.
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Affiliation(s)
| | - Claire J. Standley
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
- Center for Global Health Science and Security, Georgetown University Medical Center, Washington, DC, USA
| | - Shweta Bansal
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Colin J. Carlson
- Department of Biology, Georgetown University, Washington, DC, USA
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
- Center for Global Health Science and Security, Georgetown University Medical Center, Washington, DC, USA
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8
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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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9
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Frallonardo L, Di Gennaro F, Panico GG, Novara R, Pallara E, Cotugno S, Guido G, De Vita E, Ricciardi A, Totaro V, Camporeale M, De Iaco G, Bavaro DF, Lattanzio R, Patti G, Brindicci G, Papagni R, Pellegrino C, Santoro CR, Segala FV, Putoto G, Nicastri E, Saracino A. Onchocerciasis: Current knowledge and future goals. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.986884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human Onchocerciasis, caused by infection by the filarial nematode Onchocerca volvulus, is a neglected public health disease that affects millions of people in the endemic regions of sub-Saharan Africa and Latin America. It is also called river blindness because the Blackflies that transmit infection breeds in rapidly flowing fresh water streams and rivers. This review features state-of-the-art data on the parasite, its endobacteria Wolbachia, the prevalence of the infection and its geographical distribution, its diagnostics, the interaction between the parasite and its host, and the pathology of Onchocerciasis. By development and optimization of the control measures, transmission by the vector has been interrupted in foci of countries in the Americas (Colombia, Ecuador, Mexico, and Guatemala)and inSudan, followed by Onchocerciasis eliminations. The current state and future perspectives for vector control and elimination strategy are described.
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10
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Jacobsen KH, Andress BC, Bhagwat EA, Bryant CA, Chandrapu VR, Desmonts CG, Matthews TM, Ogunkoya A, Wheeler TJ, Williams AS. A call for loiasis to be added to the WHO list of neglected tropical diseases. THE LANCET. INFECTIOUS DISEASES 2022; 22:e299-e302. [PMID: 35500592 DOI: 10.1016/s1473-3099(22)00064-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Loiasis, also called African eye worm, is not currently on WHO's list of priority neglected tropical diseases, even though the risk that individuals with high Loa loa microfilarial densities will develop potentially fatal encephalopathy when they take ivermectin has complicated efforts to use mass drug administration for onchocerciasis (river blindness) and lymphatic filariasis control in co-endemic areas. At least 10 million residents of central and west Africa are thought to have loiasis, which causes painful and itchy subcutaneous oedema, arthralgia, and discomfort when adult helminths that are 3-7 cm in length are present under the conjunctiva of the eye. High levels of microfilaraemia are associated with renal, cardiac, neurological, and other sequelae, and an increased risk of death. The public health burden of loiasis could be greatly reduced with expanded use of diagnostic tests, anthelmintic treatment, and control of the Chrysops spp (tabanid flies) vectors that transmit the parasite. Loiasis should be added to the next revision of the WHO neglected tropical disease priority list, not merely because its inclusion will support the elimination of other skin and subcutaneous neglected tropical diseases, but also because of the complications caused by loiasis itself.
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Affiliation(s)
- Kathryn H Jacobsen
- Department of Health Studies, University of Richmond, Richmond, VA, USA.
| | - Bailey C Andress
- Department of Health Studies, University of Richmond, Richmond, VA, USA
| | - Elina A Bhagwat
- Department of Health Studies, University of Richmond, Richmond, VA, USA
| | - Ciera A Bryant
- Department of Health Studies, University of Richmond, Richmond, VA, USA
| | | | | | - Tania M Matthews
- Department of Health Studies, University of Richmond, Richmond, VA, USA
| | - Akeem Ogunkoya
- Department of Health Studies, University of Richmond, Richmond, VA, USA
| | - Tristan J Wheeler
- Department of Health Studies, University of Richmond, Richmond, VA, USA
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11
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Pallara E, Cotugno S, Guido G, De Vita E, Ricciardi A, Totaro V, Camporeale M, Frallonardo L, Novara R, Panico GG, Puzo P, Alessio G, Sablone S, Mariani M, De Iaco G, Milano E, Bavaro DF, Lattanzio R, Patti G, Papagni R, Pellegrino C, Saracino A, Di Gennaro F. Loa loa in the Vitreous Cavity of the Eye: A Case Report and State of Art. Am J Trop Med Hyg 2022; 107:tpmd220274. [PMID: 35914685 PMCID: PMC9490677 DOI: 10.4269/ajtmh.22-0274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/06/2022] [Indexed: 11/20/2022] Open
Abstract
Loa loa is a filarial nematode responsible for loiasis, endemic to West-Central Africa south of the Sahara and transmitted by flies. This study reports a case of L. loa in the vitreous cavity of the eye of a young patient, along with an in-depth literature review. A 22-year-old woman from Cameroon who migrated from Cameroon to Italy was referred to the Emergency Ophthalmology Department at Policlinico di Bari in July 2021 with the presence of a moving parasite in the subconjunctiva of the left eye. A recent onset of a papular lesion on the dorsal surface of the right wrist and a nodular lesion in the scapular region were detected. L. loa filariasis was diagnosed based on anamnestic data, clinical and paraclinical signs, and a parasitological test confirming the presence of microfilariae in two blood samples collected in the morning of two different days. Because of the unavailability of diethylcarbamazine (DEC), albendazole (ALB) 200 mg twice daily was administered for 21 days. A mild exacerbation of pruritus occurred during treatment, but resolved with the use of an antihistamine. A single dose of 12 mg ivermectin was prescribed at the end of the treatment with albendazole. Unlike other endemic parasite infections, L. loa is not included in the Global Program to Eliminate Lymphatic Filariasis, because it is not mentioned in the WHO and CDC list of neglected tropical diseases. This can result in an overall risk of lack of attention and studies on loiasis, with lack of data on global burden of the disease.
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Affiliation(s)
- Elisabetta Pallara
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Sergio Cotugno
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Giacomo Guido
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Elda De Vita
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Aurelia Ricciardi
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Valentina Totaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Michele Camporeale
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Luisa Frallonardo
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Roberta Novara
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Gianfranco G. Panico
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Pasquale Puzo
- Section of Ophthalmology, Department of Medical Science, Neuroscience and Senso Organs, Bari Policlinico Hospital University of Bari, Bari, Italy
| | - Giovanni Alessio
- Section of Ophthalmology, Department of Medical Science, Neuroscience and Senso Organs, Bari Policlinico Hospital University of Bari, Bari, Italy
| | - Sara Sablone
- Section of Legal Medicine, Department of Interdisciplinary Medicine, University of Bari “Aldo Moro,” Bari, Italy
| | - Michele Mariani
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Giuseppina De Iaco
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Eugenio Milano
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Davide F. Bavaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Rossana Lattanzio
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Giulia Patti
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Roberta Papagni
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Carmen Pellegrino
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Annalisa Saracino
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
| | - Francesco Di Gennaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro,” Bari, Italy
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12
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Ta-Tang TH, Febrer-Sendra B, Berzosa P, Rubio JM, Romay-Barja M, Ncogo P, Agudo D, Herrador Z, Fernández-Soto P, Muro A, Benito A. Comparison of three PCR-based methods to detect Loa loa and Mansonella perstans in long-term frozen storage dried blood spots. Trop Med Int Health 2022; 27:686-695. [PMID: 35653502 DOI: 10.1111/tmi.13786] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Loa loa and Mansonella perstans are two very common filarial species in Africa. Although microscopy is the traditional diagnostic method for human filariasis, several polymerase chain reaction (PCR) methods have emerged as an alternative approach for identifying filarial parasites. The aim of this study is to compare three molecular methods and decide which is the most suitable for diagnosing human loiasis and mansonellosis in non-endemic regions using dried blood spot (DBS) as a medium for sample collection and storage. METHODS A total of 100 DBS samples, with their corresponding thin and thick blood smears, were selected for this study. Microscopy was used as the reference method to diagnose and calculate the microfilaraemia. Filarial DNA was extracted using the saponin/Chelex method and the DNA isolated was assayed by Filaria-real time-PCR, filaria-nested PCR, and cytochrome oxidase I PCR. All PCR products were subsequently purified and sequenced. The statistical values for each molecular test were calculated and compared. RESULTS Overall, 64 samples were identified as negative by all tests and a further 36 samples were positive by at least one of the methods used. The sensitivity and specificity were similar for the different molecular methods, all of which demonstrated good agreement with microscopy. CONCLUSIONS Based on this study, and from a practical point of view (single and short amplification round), the optimal technique for diagnosing filarial infection in non-endemic regions is filaria-real time-PCR, which presents high sensitivity and specificity and is also able to detect a wide range of human filariae.
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Affiliation(s)
- Thuy-Huong Ta-Tang
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Begoña Febrer-Sendra
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Pedro Berzosa
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - José Miguel Rubio
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - María Romay-Barja
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Policarpo Ncogo
- Ministry of Health, Malabo, Equatorial Guinea.,Fundación Estatal, Salud, Infancia y Bienestar Social, Madrid, Spain
| | - Diego Agudo
- Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain
| | - Zaida Herrador
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Pedro Fernández-Soto
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Antonio Muro
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Agustín Benito
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
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13
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Ehrens A, Hoerauf A, Hübner MP. Current perspective of new anti-Wolbachial and direct-acting macrofilaricidal drugs as treatment strategies for human filariasis. GMS INFECTIOUS DISEASES 2022; 10:Doc02. [PMID: 35463816 PMCID: PMC9006451 DOI: 10.3205/id000079] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Filarial diseases like lymphatic filariasis and onchocerciasis belong to the Neglected Tropical Diseases and remain a public health problem in endemic countries. Lymphatic filariasis and onchocerciasis can lead to stigmatizing pathologies and present a socio-economic burden for affected people and their endemic countries. Current treatment recommendations by the WHO include mass drug administration with ivermectin for the treatment of onchocerciasis and a combination of ivermectin, albendazole and diethylcarbamazine (DEC) for the treatment of lymphatic filariasis in areas that are not co-endemic for onchocerciasis or loiasis. Limitations of these treatment strategies are due to potential severe adverse events in onchocerciasis and loiasis patients following DEC or ivermectin treatment, respectively, the lack of a macrofilaricidal efficacy of those drugs and the risk of drug resistance development. Thus, to achieve the elimination of transmission of onchocerciasis and the elimination of lymphatic filariasis as a public health problem by 2030, the WHO defined in its roadmap that new alternative treatment strategies with macrofilaricidal compounds are required. Within a collaboration of the non-profit organizations Drugs for Neglected Diseases initiative (DNDi), the Bill & Melinda Gates Foundation, and partners from academia and industry, several new promising macrofilaricidal drug candidates were identified, which will be discussed in this review.
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Affiliation(s)
- Alexandra Ehrens
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Marc P. Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
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14
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Sumo L, Ntonifor NH, Afor AR, Bopda J, Bamou Heumou R, Ondoua Nganjou GS, Nana Djeunga HC. Loiasis is endemic in the Ndikinimeki Health District (Centre Region, Cameroon) but does not represent a hindrance to onchocerciasis elimination. Acta Trop 2022; 225:106218. [PMID: 34755644 DOI: 10.1016/j.actatropica.2021.106218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/02/2021] [Accepted: 10/25/2021] [Indexed: 11/19/2022]
Abstract
Community-Directed Treatment with Ivermectin (CDTI) is the strategy of choice to fight onchocerciasis in Africa. In areas where loiasis is endemic, onchocerciasis control and/or elimination is hindered by severe adverse events (SAEs) occurring after ivermectin mass treatments. This study aimed at (i) investigating the impact of two decades of CDTI on L. loa clinical and parasitological indicators in the Ndikinimeki Health District, and (ii) assessing the risk of SAEs after this long-term preventive chemotherapy. A cluster-based cross-sectional survey was conducted in the six Health Areas of the Ndikinimeki Health District. All volunteers underwent day-time calibrated thick blood smears to search for L. loa microfilariae, as well as an interview to assess the history of migration of eye worm and Calabar swelling. The overall prevalence of L. loa microfilaraemia was 2.2 % (95% CI: 1.3-3.7%), and the proportions of individuals who had already experienced eye worm and/or Calabar swelling were 1.0% and 0.5%, respectively. The mean microfilarial density was 63.55 (SD: 559.17; maximum: 9220.0) mf/mL. These findings indicate that (i) the long-term ivermectin-based preventive chemotherapy against onchocerciasis significantly reduced L. loa clinical and parasitological indicators, and (ii) the risk of developing neurologic and potentially fatal SAE after ivermectin mass treatment is zero in the Ndikinimeki Health District.
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Affiliation(s)
- Laurentine Sumo
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon; Centre for Research on Filariasis and other tropical Diseases (CRFilMT), Yaounde, Cameroon.
| | - Ngum Helen Ntonifor
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon.
| | - Aza'ah René Afor
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon.
| | - Jean Bopda
- Centre for Research on Filariasis and other tropical Diseases (CRFilMT), Yaounde, Cameroon.
| | - Rolph Bamou Heumou
- Centre for Research on Filariasis and other tropical Diseases (CRFilMT), Yaounde, Cameroon.
| | - Gabriella S Ondoua Nganjou
- Centre for Research on Filariasis and other tropical Diseases (CRFilMT), Yaounde, Cameroon; Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, Yaounde, Cameroon..
| | - Hugues C Nana Djeunga
- Centre for Research on Filariasis and other tropical Diseases (CRFilMT), Yaounde, Cameroon; Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, Yaounde, Cameroon..
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15
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Forrer A, Wanji S, Obie ED, Nji TM, Hamill L, Ozano K, Piotrowski H, Dean L, Njouendou AJ, Ekanya R, Ndongmo WPC, Fung EG, Nnamdi DB, Abong RA, Beng AA, Eyong ME, Ndzeshang BL, Nkimbeng DA, Teghen S, Suireng A, Ashu EE, Kah E, Murdoch MM, Thomson R, Theobald S, Enyong P, Turner JD, Taylor MJ. Why onchocerciasis transmission persists after 15 annual ivermectin mass drug administrations in South-West Cameroon. BMJ Glob Health 2021; 6:bmjgh-2020-003248. [PMID: 33431378 PMCID: PMC7802695 DOI: 10.1136/bmjgh-2020-003248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 11/11/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Introduction Onchocerciasis is targeted for elimination mainly with annual community-directed treatment with ivermectin (CDTI). High infection levels have been reported in South-West Cameroon, despite ≥15 years of CDTI. The aim of this study was to assess factors associated with continued onchocerciasis transmission and skin disease. Methods A large-scale cross-sectional study was conducted in 2017 in 20 communities in a loiasis-risk area in South-West Cameroon. A mixed-methods approach was used. Associations between infection levels, skin disease and adherence to CDTI were assessed using mixed regression modelling. Different community members’ perception and acceptability of the CDTI strategy was explored using semi-structured interviews. Results Onchocerciasis prevalence was 44.4% among 9456 participants. 17.5% of adults were systematic non-adherers and 5.9% participated in ≥75% of CDTI rounds. Skin disease affected 1/10 participants, including children. Increasing self-reported adherence to CDTI was associated with lower infection levels in participants aged ≥15 years but not in children. Adherence to CDTI was positively influenced by perceived health benefits, and negatively influenced by fear of adverse events linked with economic loss. Concern of lethal adverse events was a common reason for systematic non-adherence. Conclusion CDTI alone is unlikely to achieve elimination in those high transmission areas where low participation is commonly associated with the fear of adverse events, despite the current quasi absence of high-risk levels of loiasis. Such persisting historical memories and fear of ivermectin might impact adherence to CDTI also in areas with historical presence but current absence of loiasis. Because such issues are unlikely to be tackled by CDTI adaptive measures, alternative strategies are needed for onchocerciasis elimination where negative perception of ivermectin is an entrenched barrier to community participation in programmes.
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Affiliation(s)
- Armelle Forrer
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Samuel Wanji
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Elisabeth Dibando Obie
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Theobald Mue Nji
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Louise Hamill
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Kim Ozano
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Helen Piotrowski
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Laura Dean
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Abdel J Njouendou
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Relindis Ekanya
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Winston Patrick Chounna Ndongmo
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Ebua Gallus Fung
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Dum-Buo Nnamdi
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Department of Sociology and Anthropology, University of Buea, Buea, Cameroon
| | - Raphael A Abong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Amuam Andrew Beng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Mathias Esum Eyong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Bertrand L Ndzeshang
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Desmond Akumtoh Nkimbeng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Samuel Teghen
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Anicetus Suireng
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Ernerstine Ebot Ashu
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Emmanuel Kah
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Michele M Murdoch
- Watford General Hospital, West Herts Hospitals NHS Trust, Watford, UK
| | - Rachael Thomson
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Sally Theobald
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, Liverpool, UK
| | - Peter Enyong
- Department of Disease Control, Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Joseph D Turner
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
| | - Mark J Taylor
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, Merseyside, UK
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16
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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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17
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Vinkeles Melchers NVS, Coffeng LE, Boussinesq M, Pedrique B, Pion SDS, Tekle AH, Zouré HGM, Wanji S, Remme JH, Stolk WA. Projected Number of People With Onchocerciasis-Loiasis Coinfection in Africa, 1995 to 2025. Clin Infect Dis 2021; 70:2281-2289. [PMID: 31304961 PMCID: PMC7245158 DOI: 10.1093/cid/ciz647] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/12/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Onchocerciasis elimination through mass drug administration (MDA) is hampered by coendemicity of Loa loa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and loiasis prevalence and estimated the number of coinfected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS Focusing on regions with suspected loiasis transmission in 14 countries, we overlaid precontrol maps of loiasis and onchocerciasis prevalence to calculate precontrol prevalence of coinfection by 5 km2 × 5 km2 pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted prevalence of both infections and coinfection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137 000 people were estimated to also have L. loa hypermicrofilaremia (≥20 000 L. loa mf/mL) in 1995, declining to 31 000 in 2025. In 2025, 92.8% of coinfected cases with loiasis hypermicrofilaremia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS Loiasis coinfection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31 000 coinfected people still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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Affiliation(s)
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Michel Boussinesq
- Unité Mixte Internationale 233 TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM U1175, University of Montpellier, Montpellier, France
| | - Belén Pedrique
- Research & Development Department, Drugs for Neglected Diseases initiative, and, Geneva, Switzerland
| | - Sébastien D S Pion
- Unité Mixte Internationale 233 TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM U1175, University of Montpellier, Montpellier, France
| | - Afework H Tekle
- Preventive Chemotherapy and Transmission Control Unit, Control of Neglected Tropical Diseases Department, World Health Organization, Geneva, Switzerland
| | - Honorat G M Zouré
- Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), World Health Organization, Regional Office for Africa, Cité du Djoué, Brazzaville, Republic of Congo
| | - Samuel Wanji
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, Cameroon
| | | | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands
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18
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Ta-Tang TH, Berzosa P, Rubio JM, Romay-Barja M, Ncogo P, Agudo D, Herrador Z, Cerrada-Gálvez L, Benito A. Evaluation of LAMP for the diagnosis of Loa loa infection in dried blood spots compared to PCR-based assays and microscopy. Mem Inst Oswaldo Cruz 2021; 116:e210210. [PMID: 35170676 PMCID: PMC8843042 DOI: 10.1590/0074-02760210210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/14/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Loa loa is a filarial species found exclusively in West and Central Africa. Microscopy is the traditional diagnosis method for human loiasis. Several molecular methods have developed as an alternative approach for identification of L. loa filarial parasites. OBJECTIVES The aim of this study was to evaluate a Loa-Loop-mediated isothermal amplification (LAMP) assay to diagnose loiasis disease on dried blood spots (DBS) samples, compared to microscopy, filaria-real time-polymerase chain reaction (PCR) and nested-Loa PCR. METHODS A total of 100 DBS samples and 100 blood smears were used for this study. DNA was extracted using saponin/Chelex method. DNA isolated was assayed by a Loa-LAMP assay in parallel to microscopy, filaria-real time PCR and nested-Loa PCR. The sensitivities and specificities of Loa-LAMP assay was computed comparing to each one of the reference methods. FINDINGS Loa-LAMP’s sensitivity was more than 90% and specificity was nearly 100% when compared to molecular methods. On the other hand, sensitivity was decreased a bit when Loa-LAMP faced microscopy, but keeping the other statistical values high. MAIN CONCLUSIONS Loa-LAMP is an appropriate method for loiasis diagnosis in endemic areas. Though, it has disadvantages like the reagents’ high price at the moment and not to be able to detect more filarial species at once.
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Affiliation(s)
- Thuy-Huong Ta-Tang
- National Centre of Tropical Medicine, Spain; Cooperative Research Network on Tropical Diseases, Spain
| | - Pedro Berzosa
- National Centre of Tropical Medicine, Spain; Cooperative Research Network on Tropical Diseases, Spain
| | - José Miguel Rubio
- National Microbiology Centre, Spain; Cooperative Research Network on Tropical Diseases, Spain
| | - María Romay-Barja
- National Centre of Tropical Medicine, Spain; Cooperative Research Network on Tropical Diseases, Spain
| | - Policarpo Ncogo
- Ministry of Health, Equatorial Guinea; Fundación Estatal, Spain
| | | | - Zaida Herrador
- National Centre of Tropical Medicine, Spain; Cooperative Research Network on Tropical Diseases, Spain
| | | | - Agustín Benito
- National Centre of Tropical Medicine, Spain; Cooperative Research Network on Tropical Diseases, Spain
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19
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Collateral Impact of Community-Directed Treatment with Ivermectin (CDTI) for Onchocerciasis on Parasitological Indicators of Loa loa Infection. Pathogens 2020; 9:pathogens9121043. [PMID: 33322724 PMCID: PMC7764802 DOI: 10.3390/pathogens9121043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 11/17/2022] Open
Abstract
Ivermectin (IVM) is a broad spectrum endectocide whose initial indication was onchocerciasis. Although loiasis is not among its indications, IVM also exhibits antiparasitic activity against Loa loa. IVM-based preventive chemotherapies (PCs), so-called community-directed treatment with ivermectin (CDTI), have led to the interruption of transmission of onchocerciasis in some foci. A cross-sectional study was conducted in the Yabassi Health District where CDTI have been implemented since 20 years to fight onchocerciasis. All volunteers aged ≥ 5 years underwent daytime calibrated thick blood smears to search for L. loa microfilariae (mf). The prevalence of loiasis was 3.7% (95% CI: 2.2-6.2), significantly lower than its baseline prevalence (12.4%; 95% CI: 10.1-15.2; Chi-Square = 21.4; df = 1; p < 0.0001). Similarly, the microfilarial density was significantly low (mean = 1.8 mf/mL; SD = 13.6; max = 73,600) compared to baseline microfilarial density (mean = 839.3 mf/mL; SD = 6447.1; max = 130,840; Wilcoxon W = 179,904.5; p < 0.0001). This study revealed that the endemicity level of loiasis was significantly low compared to its baseline value, indicating a significant impact of IVM-based PC on this filarial disease. However, transmission is still ongoing, and heavily infected individuals are still found in communities, supporting why some individuals are still experiencing severe adverse events despite > 2 decades of CDTI in this Health District.
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20
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Tsapi EM, Todjom FG, Gamago GA, Pone JW, Teukeng FFD. Prevalence of onchocerciasis after seven years of continuous community-directed treatment with ivermectin in the Ntui health district, Centre region, Cameroon. Pan Afr Med J 2020; 36:180. [PMID: 32952824 PMCID: PMC7467880 DOI: 10.11604/pamj.2020.36.180.20765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/23/2020] [Indexed: 11/18/2022] Open
Abstract
Introduction onchocerciasis is one of the major infectious diseases caused by Onchocerca volvulus. This parasite is responsible for chronic cutaneous and ocular diseases affecting more than 37 million people of whom 99% are in Africa. The study was conducted in the health district of Ntui from June to September 2016 to determine the prevalence of O. volvulus infection after seven years of massive administration of ivermectin. Methods two cutaneous snips were made at the iliac crests level in volunteers. These tissues were incubated in physiological saline water and were examined for parasitological investigations in the laboratory. Results a total of 310 participants were randomly selected, of whom 170 (54.8%) were women and 140 (45.1%) were men aged 6 to 83 years, thus giving a sex ratio of 1.2 in favour of women. After parasitological analysis, 26 participants had microfilaraemia, of whom 15 (10.7%) were men and 11 (6.4%) were women. The most infected age group was 16 to 26 years (12.5%). The highest infection rates were found among farmers (11%) and participants living in the village of Essougly (26.6%). No significant differences in prevalence values between the different groups were noted, whatever the parameter considered. Conclusion the prevalence of onchocerciasis in the health district of Ntui has declined from a hyperendemic to a hypoendemic state after seven years of massive administration of ivermectin. However, careful monitoring of onchocerciasis should be continued to prevent the area from returning to its original hyperendemicity.
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Affiliation(s)
| | - Françoise Guemgne Todjom
- Research Unit of Biology and Applied Ecology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Guy-Armand Gamago
- Faculté des Sciences de la Santé, Université des Montagnes, Bangangté, Cameroon
| | - Josué Wabo Pone
- Faculté des Sciences de la Santé, Université des Montagnes, Bangangté, Cameroon
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21
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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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Mogoung-Wafo AE, Nana-Djeunga HC, Domche A, Fossuo-Thotchum F, Bopda J, Mbickmen-Tchana S, Djomo-Kamga H, Kamgno J. Prevalence and intensity of Loa loa infection over twenty-three years in three communities of the Mbalmayo health district (Central Cameroon). BMC Infect Dis 2019; 19:146. [PMID: 30760228 PMCID: PMC6373160 DOI: 10.1186/s12879-019-3776-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 02/04/2019] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Loiasis is a vector-borne parasitic disease due to Loa loa and transmitted to humans by tabanids of the genus Chrysops. Loiasis has been historically considered as the second or third most common reason for medical consultation after malaria, and a recent study has reported an excess mortality associated with the infection. However, the clinical impact of this filarial disease is yet to be elucidated, and it is still considered a benign disease eliciting very little attention. As a consequence of post-treatment severe adverse events occurring in individuals harboring very high Loa microfilarial loads, ivermectin is not recommended in onchocerciasis hypo-endemic areas that are co-endemic for loiasis. Without treatment, it is likely that the transmission of the disease and the morbidity associated with the infection will increase over time. This study aimed at investigating the long-term trends in prevalence and intensity of Loa loa infection in an area where no mass anti-filarial treatment has ever been distributed. METHODS A cross-sectional survey was conducted in three communities of the Mbalmayo health district (Central Cameroon). All volunteers, males and females aged five years and above, underwent daytime calibrated thick blood smears (CTBS) to search for L. loa microfilariae (mf). A structured questionnaire was administered to assess the history of both loiasis related clinical signs and migration of enrollees. RESULTS The prevalence of loiasis was 27.3% (95% CI: 22.3-32.9) in the three surveyed communities, with a mean mf density of 1922.7 (sd: 6623.2) mf/mL. Loa loa infection rate was higher amongst females than in males (p = 0.0001) and was positively associated with age of (OR = 1.018; p = 0.007). The intensity of infection was higher among males than in females (p < 0.0001), and displayed a convex in form trends with age groups. The follow up over 23 years revealed that both the rate and intensity of infection were similar to baseline. CONCLUSIONS The prevalence and intensity of Loa loa infection 23 years on is stable over time, indicating that this filarial disease might be noncumulative as regarded till now.
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Affiliation(s)
- Aude E. Mogoung-Wafo
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
| | - Hugues C. Nana-Djeunga
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - André Domche
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
| | | | - Jean Bopda
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
| | - Steve Mbickmen-Tchana
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
| | - Honoré Djomo-Kamga
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases, PO Box 5797, Yaounde, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, PO Box 1364, Yaounde, Cameroon
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