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Ayisi F, de Souza DK, Tallant J, Biholong BD, Fokam EB, Boakye DA. Onchocerciasis in the Cameroon-Chad border area after more than 20 years of annual mass ivermectin distribution. Parasit Vectors 2024; 17:219. [PMID: 38741212 DOI: 10.1186/s13071-024-06284-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/17/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND The main vectors of onchocerciasis in Africa are Simulium damnosum sensu lato, which transmit the causative agent Onchocerca volvulus. The force of transmission is driven by the vector density, hence influencing the disease prevalence and intensity. Onchocerciasis is currently targeted for elimination using mass drug administration (MDA) of ivermectin, a potent microfilaricide. MDA in Cameroon began in 1987 in the Vina Valley, an endemic cross-border area with Chad, known for high vector densities and precontrol endemicity. Evaluations in 2008-2010 in this area showed ongoing transmission, while border areas in Chad were close to interrupting transmission. This study aimed to evaluate transmission in this area after several rounds of MDA since the last evaluation surveys. METHODS Black flies were collected by human landing catches at seven border sites in Cameroon, twice a week, from August 2021 to March 2022. A fraction of the flies was dissected for parity assessment and identification of Onchocerca larval stages. The transmission indices were estimated. Black fly larvae were also collected from the breeding sites at the fly catching sites and identified to species level by cytotaxonomy. RESULTS A total of 14,303 female flies were collected, and 6918 were dissected. Of these, 4421 (64.0%) were parous. The total biting rates were high, reaching up to 16,407 bites/person/study period, and transmission potential (third-stage larvae (L3) from head/all L3) were 367/702, 146/506, 51/55, 20/32, 0/3, 0/0, and 0/0 infective larvae/person, respectively, for Mbere-Tchad, Babidan, Hajam/V5, Gor, Djeing, Touboro, and Koinderi. Infectivity rates (L3 from head) were 16.00, 12.75, 5.15, and 4.07 infective females (L3H)/1000 parous flies for Haijam, Mbere-Tchad, Babidan, and Gor, respectively. These values exceed the World Health Organization (WHO) thresholds of ≤ 20 annual transmission potential (ATP) or < 1 infective female/1000 parous females. The major vectors identified were Simulium damnosum sensu stricto, S. squamosum, and for the first time in the area, S. yahense. CONCLUSIONS More than 20 years of MDA has not eliminated onchocerciasis in the study area; hence, this area is a potential source of reintroduction of onchocerciasis in Chad and would require alternative treatment strategies. Many factors such as MDA efficiency, effectiveness of ivermectin, and cytospecies composition may be contributing to transmission persistence.
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Affiliation(s)
- Franklin Ayisi
- African Regional Postgraduate Programme in Insect Science (ARPPIS), University of Ghana, PMB LG 59, Legon, Accra, Ghana.
- National Onchocerciasis Control Programme, Sub Department in Charge of Malaria and Neglected Tropical Diseases, Department of Control of Diseases, Epidemics and Pandemics, Ministry of Public Health, Yaoundé, Cameroon.
| | - Dziedzom Komi de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | | | - Benjamin Didier Biholong
- National Onchocerciasis Control Programme, Sub Department in Charge of Malaria and Neglected Tropical Diseases, Department of Control of Diseases, Epidemics and Pandemics, Ministry of Public Health, Yaoundé, Cameroon
| | - Eric Bertrand Fokam
- Department of Animal Biology and Conservation, University of Buea, Buea, Cameroon
| | - Daniel Adjei Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- The END Fund, New York, NY, USA
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Konlan M, Abassawah Danquah B, Okyere E, Osman S, Amenyo Kessie J, Kobina Donkoh E. Global stability analysis and modelling onchocerciasis transmission dynamics with control measures. Infect Ecol Epidemiol 2024; 14:2347941. [PMID: 38736969 PMCID: PMC11086017 DOI: 10.1080/20008686.2024.2347941] [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: 12/27/2022] [Accepted: 04/22/2024] [Indexed: 05/14/2024] Open
Abstract
Background: Onchocerciasis infection is one of the neglected tropical diseases targeted for eradication by 2030. The disease is usually transmitted to humans through the bites of black flies. These black flies mostly breed near well-oxygenated fast-running water bodies. The disease is common in mostly remote agricultural villages near rivers and streams. Objective: In this study, a deterministic model describing the infection dynamics of human onchocerciasis disease with control measures is presented. Methods: We derived the model's reproductive number and used a stability theorem of a Metzler matrix to show that disease-free equilibrium is both locally and globally asymptotically stable whenever the reproductive number is less than one. Parameter contribution was conducted using sensitivity analysis. The model endemic equation is shown to be a cubic polynomial in the presence of infected immigrants and a quadratic form in their absence. Results: When the inflow of infected immigrants is null, the model endemic equation may admit a unique equilibrium if the reproductive number is greater than one, or admits multiple endemic equilibria if the reproductive number is less than unity. We carried out a sensitivity analysis to identify the significant parameters that contribute to onchocerciasis spread. Conclusion: Onchocerciasis disease can be eradicated if the importation of infected immigrants is properly monitored. The integration of the One Health concept in the public health system is key in tackling the emergence and spread of diseases.
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Affiliation(s)
- Musah Konlan
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana
| | - Baaba Abassawah Danquah
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana
| | - Eric Okyere
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana
| | - Shaibu Osman
- Department of Basic Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Justice Amenyo Kessie
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana
| | - Elvis Kobina Donkoh
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, Ghana
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Mutono N, Basáñez MG, James A, Stolk WA, Makori A, Kimani TN, Hollingsworth TD, Vasconcelos A, Dixon MA, de Vlas SJ, Thumbi SM. Elimination of transmission of onchocerciasis (river blindness) with long-term ivermectin mass drug administration with or without vector control in sub-Saharan Africa: a systematic review and meta-analysis. Lancet Glob Health 2024; 12:e771-e782. [PMID: 38484745 PMCID: PMC11009120 DOI: 10.1016/s2214-109x(24)00043-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 01/11/2024] [Accepted: 01/19/2024] [Indexed: 04/15/2024]
Abstract
BACKGROUND WHO has proposed elimination of transmission of onchocerciasis (river blindness) by 2030. More than 99% of cases of onchocerciasis are in sub-Saharan Africa. Vector control and mass drug administration of ivermectin have been the main interventions for many years, with varying success. We aimed to identify factors associated with elimination of onchocerciasis transmission in sub-Saharan Africa. METHODS For this systematic review and meta-analysis we searched for published articles reporting epidemiological or entomological assessments of onchocerciasis transmission status in sub-Saharan Africa, with or without vector control. We searched MEDLINE, PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials, African Index Medicus, and Google Scholar databases for all articles published from database inception to Aug 19, 2023, without language restrictions. The search terms used were "onchocerciasis" AND "ivermectin" AND "mass drug administration". The three inclusion criteria were (1) focus or foci located in Africa, (2) reporting of elimination of transmission or at least 10 years of ivermectin mass drug administration in the focus or foci, and (3) inclusion of at least one of the following assessments: microfilarial prevalence, nodule prevalence, Ov16 antibody seroprevalence, and blackfly infectivity prevalence. Epidemiological modelling studies and reviews were excluded. Four reviewers (NM, AJ, AM, and TNK) extracted data in duplicate from the full-text articles using a data extraction tool developed in Excel with columns recording the data of interest to be extracted, and a column where important comments for each study could be highlighted. We did not request any individual-level data from authors. Foci were classified as achieving elimination of transmission, being close to elimination of transmission, or with ongoing transmission. We used mixed-effects meta-regression models to identify factors associated with transmission status. This study is registered in PROSPERO, CRD42022338986. FINDINGS Of 1525 articles screened after the removal of duplicates, 75 provided 282 records from 238 distinct foci in 19 (70%) of the 27 onchocerciasis-endemic countries in sub-Saharan Africa. Elimination of transmission was reported in 24 (9%) records, being close to elimination of transmission in 86 (30%) records, and ongoing transmission in 172 (61%) records. I2 was 83·3% (95% CI 79·7 to 86·3). Records reporting 10 or more years of continuous mass drug administration with 80% or more therapeutic coverage of the eligible population yielded significantly higher odds of achieving elimination of transmission (log-odds 8·5 [95% CI 3·5 to 13·5]) or elimination and being close to elimination of transmission (42·4 [18·7 to 66·1]) than those with no years achieving 80% coverage or more. Reporting 15-19 years of ivermectin mass drug administration (22·7 [17·2 to 28·2]) and biannual treatment (43·3 [27·2 to 59·3]) were positively associated with elimination and being close to elimination of transmission compared with less than 15 years and no biannual mass drug administration, respectively. Having had vector control without vector elimination (-42·8 [-59·1 to -26·5]) and baseline holoendemicity (-41·97 [-60·6 to -23·2]) were associated with increased risk of ongoing transmission compared with no vector control and hypoendemicity, respectively. Blackfly disappearance due to vector control or environmental change contributed to elimination of transmission. INTERPRETATION Mass drug administration duration, frequency, and coverage; baseline endemicity; and vector elimination or disappearance are important determinants of elimination of onchocerciasis transmission in sub-Saharan Africa. Our findings underscore the importance of improving and sustaining high therapeutic coverage and increasing treatment frequency if countries are to achieve elimination of onchocerciasis transmission. FUNDING The Bill & Melinda Gates Foundation and Neglected Tropical Diseases Modelling Consortium, UK Medical Research Council, and Global Health EDCTP3 Joint Undertaking. TRANSLATIONS For the Swahili, French, Spanish and Portuguese translations of the abstract see Supplementary Materials section.
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Affiliation(s)
- Nyamai Mutono
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya; Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA.
| | - Maria-Gloria Basáñez
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK; London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
| | - Ananthu James
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Anita Makori
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya; Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Teresia Njoki Kimani
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya; Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA; Ministry of Health Kenya, Kiambu Town, Kenya
| | | | | | - Matthew A Dixon
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK; London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - S M Thumbi
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya; Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA; Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, UK
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Harahap Y, Salsabila S, Saputri FA. Development and validation of ivermectin quantification method in volumetric absorptive microsampling using liquid chromatography-tandem mass spectrometry. Heliyon 2024; 10:e29606. [PMID: 38665567 PMCID: PMC11044035 DOI: 10.1016/j.heliyon.2024.e29606] [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: 10/29/2023] [Revised: 03/14/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Background Ivermectin is a broad-spectrum anthelmintic used to control onchocerciasis from nematode parasites. As an anthelmintic, ivermectin is designed to have high levels in the gastrointestinal tract, so that the systemic intake is relatively low. Due to the very small concentration of ivermectin, a selective and sensitive approach is needed for the analysis of ivermectin in blood. Several methods have been developed using plasma and Dried Blood Spots, but there are still shortcomings due to hematocrit effects. Therefore, this study was conducted to establish a validated ivermectin analysis method with doramectin as the internal standard in using Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry. Methods Mass spectrometry equipped with triple quadrupole and positive electrospray ionization mode was used to conduct the analysis. For the biological matrix, whole blood was used by Volumetric Absorptive Microsampling and extracted using a protein precipitation technique with a combination of acetonitrile and methanol (1:1). VAMS has some advantages such as not being affected by hematocrit, requires a small and fixed volume of sample, also a more efficient sampling process. Results The optimum conditions were achieved with an Acquity® UPLC BEH C18 column (1,7 μm; 2.1 × 100 mm); extracted-flow rate was 0,2 mL/min; mobile phase was 5 mM ammonium formate pH 3.00 and acetonitrile (10:90) with isocratic elution. Multiple Reaction Monitoring (MRM) detection by m/z values was 892.41 > 569.5 for ivermectin and 916,41 > 331,35 for doramectin. Conclusion The method has been appropriately validated in compliance with the 2018 guidelines laid out by the US Food and Drug Administration. Resulting the minimum detection (LLOQ) was 1 ng/mL with a linear concentration range spanning from 1 to 150 ng/mL.
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Affiliation(s)
- Yahdiana Harahap
- Faculty of Pharmacy, Universitas Indonesia, Depok, Indonesia
- Faculty of Military Pharmacy, Republic of Indonesia Defense University, Bogor, Indonesia
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Kanza EM, Nyathirombo A, Larbelee JP, Opoku NO, Bakajika DK, Howard HM, Mambandu GL, Nigo MM, Wonyarossi DU, Ngave F, Kennedy KK, Kataliko K, Bolay KM, Attah SK, Olipoh G, Asare S, Mumbere M, Vaillant M, Halleux CM, Kuesel AC. Onchocerca volvulus microfilariae in the anterior chambers of the eye and ocular adverse events after a single dose of 8 mg moxidectin or 150 µg/kg ivermectin: results of a randomized double-blind Phase 3 trial in the Democratic Republic of the Congo, Ghana and Liberia. Parasit Vectors 2024; 17:137. [PMID: 38491528 PMCID: PMC10943894 DOI: 10.1186/s13071-023-06087-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 12/07/2023] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND After ivermectin became available, diethylcarbamazine (DEC) use was discontinued because of severe adverse reactions, including ocular reactions, in individuals with high Onchocerca volvulus microfilaridermia (microfilariae/mg skin, SmfD). Assuming long-term ivermectin use led to < 5 SmfD with little or no eye involvement, DEC + ivermectin + albendazole treatment a few months after ivermectin was proposed. In 2018, the US FDA approved moxidectin for treatment of O. volvulus infection. The Phase 3 study evaluated SmfD, microfilariae in the anterior chamber (mfAC) and adverse events (AEs) in ivermectin-naïve individuals with ≥ 10 SmfD after 8 mg moxidectin (n = 978) or 150 µg/kg ivermectin (n = 494) treatment. METHODS We analyzed the data from 1463 participants with both eyes evaluated using six (0, 1-5, 6-10, 11-20, 21-40, > 40) mfAC and three pre-treatment (< 20, 20 to < 50, ≥ 50) and post-treatment (0, > 0-5, > 5) SmfD categories. A linear mixed model evaluated factors and covariates impacting mfAC levels. Ocular AEs were summarized by type and start post-treatment. Logistic models evaluated factors and covariates impacting the risk for ocular AEs. RESULTS Moxidectin and ivermectin had the same effect on mfAC levels. These increased from pre-treatment to Day 4 and Month 1 in 20% and 16% of participants, respectively. Six and 12 months post-treatment, mfAC were detected in ≈5% and ≈3% of participants, respectively. Ocular Mazzotti reactions occurred in 12.4% of moxidectin- and 10.2% of ivermectin-treated participants without difference in type or severity. The risk for ≥ 1 ocular Mazzotti reaction increased for women (OR 1.537, 95% CI 1.096-2.157) and with mfAC levels pre- and 4 days post-treatment (OR 0: > 10 mfAC 2.704, 95% CI 1.27-5.749 and 1.619, 95% CI 0.80-3.280, respectively). CONCLUSIONS The impact of SmfD and mfAC levels before and early after treatment on ocular AEs needs to be better understood before making decisions on the risk-benefit of strategies including DEC. Such decisions should take into account interindividual variability in SmfD, mfAC levels and treatment response and risks to even a small percentage of individuals.
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Affiliation(s)
- Eric M Kanza
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo
- Programme National de Lutte Contre Les Maladies Tropicales Négligées À Chimio-Thérapie Préventive (PNLMTN-CTP), Kinshasa, Democratic Republic of the Congo
| | - Amos Nyathirombo
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
- Department of Ophthalmology, Faculty of Medicine, Gulu University, Gulu, Uganda
| | - Jemmah P Larbelee
- Clinical Research Center, Liberia Institute for Biomedical Research, Bolahun, Liberia
- Ministry of Health, Monrovia, Liberia
| | - Nicholas O Opoku
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
- Department of Epidemiology and Biostatistics School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Didier K Bakajika
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
- ESPEN, African Regional Office of the World Health Organization (WHO/AFRO/ESPEN), Brazzaville, Republic of Congo
| | - Hayford M Howard
- Clinical Research Center, Liberia Institute for Biomedical Research, Bolahun, Liberia
- Ganta United Methodist Hospital, Ganta City, Nimba County, Liberia
| | - Germain L Mambandu
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
- Inspection Provinciale de La Santé de La Tshopo, Division Provinciale de La Santé de La Tshopo, Kisangani, Province de La Tshopo, Democratic Republic of the Congo
| | - Maurice M Nigo
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
- Institut Supérieur Des Techniques Médicales de Nyankunde, Bunia, Ituri, Democratic Republic of the Congo
| | - Deogratias Ucima Wonyarossi
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
| | - Françoise Ngave
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
| | - Kambale Kasonia Kennedy
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
| | - Kambale Kataliko
- Centre de Recherche en Maladies Tropicale de L'Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo
- Centre de Santé CECA 20 de Mabakanga, Beni, Nord Kivu, Democratic Republic of the Congo
| | - Kpehe M Bolay
- Clinical Research Center, Liberia Institute for Biomedical Research, Bolahun, Liberia
- National Public Health Institute of Liberia, Public Health & Medical Research, Monrovia, Liberia
| | - Simon K Attah
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
- Department of Microbiology, University of Ghana Medical School, Accra, Ghana
- Baldwin University College, Accra, Ghana
| | - George Olipoh
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
- National Assay Centre, Precious Minerals Marketing Company Ltd., Diamond House, Accra, Ghana
| | - Sampson Asare
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
- Bell Laboratories Inc, Window, WI, USA
| | - Mupenzi Mumbere
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo
- Medicines Development for Global Health (MDGH), Melbourne, Australia
| | - Michel Vaillant
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Grand Duchy of Luxembourg
| | - Christine M Halleux
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (WHO/TDR), World Health Organization, Geneva, Switzerland
| | - Annette C Kuesel
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (WHO/TDR), World Health Organization, Geneva, Switzerland.
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Hegde S, Marriott AE, Pionnier N, Steven A, Bulman C, Gunderson E, Vogel I, Koschel M, Ehrens A, Lustigman S, Voronin D, Tricoche N, Hoerauf A, Hübner MP, Sakanari J, Aljayyoussi G, Gusovsky F, Dagley J, Hong DW, O'Neill P, Ward SA, Taylor MJ, Turner JD. Combinations of the azaquinazoline anti- Wolbachia agent, AWZ1066S, with benzimidazole anthelmintics synergise to mediate sub-seven-day sterilising and curative efficacies in experimental models of filariasis. Front Microbiol 2024; 15:1346068. [PMID: 38362501 PMCID: PMC10867176 DOI: 10.3389/fmicb.2024.1346068] [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] [Received: 11/28/2023] [Accepted: 01/02/2024] [Indexed: 02/17/2024] Open
Abstract
Lymphatic filariasis and onchocerciasis are two major neglected tropical diseases that are responsible for causing severe disability in 50 million people worldwide, whilst veterinary filariasis (heartworm) is a potentially lethal parasitic infection of companion animals. There is an urgent need for safe, short-course curative (macrofilaricidal) drugs to eliminate these debilitating parasite infections. We investigated combination treatments of the novel anti-Wolbachia azaquinazoline small molecule, AWZ1066S, with benzimidazole drugs (albendazole or oxfendazole) in up to four different rodent filariasis infection models: Brugia malayi-CB.17 SCID mice, B. malayi-Mongolian gerbils, B. pahangi-Mongolian gerbils, and Litomosoides sigmodontis-Mongolian gerbils. Combination treatments synergised to elicit threshold (>90%) Wolbachia depletion from female worms in 5 days of treatment, using 2-fold lower dose-exposures of AWZ1066S than monotherapy. Short-course lowered dose AWZ1066S-albendazole combination treatments also delivered partial adulticidal activities and/or long-lasting inhibition of embryogenesis, resulting in complete transmission blockade in B. pahangi and L. sigmodontis gerbil models. We determined that short-course AWZ1066S-albendazole co-treatment significantly augmented the depletion of Wolbachia populations within both germline and hypodermal tissues of B. malayi female worms and in hypodermal tissues in male worms, indicating that anti-Wolbachia synergy is not limited to targeting female embryonic tissues. Our data provides pre-clinical proof-of-concept that sub-seven-day combinations of rapid-acting novel anti-Wolbachia agents with benzimidazole anthelmintics are a promising curative and transmission-blocking drug treatment strategy for filarial diseases of medical and veterinary importance.
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Affiliation(s)
- Shrilakshmi Hegde
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Amy E. Marriott
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nicolas Pionnier
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Andrew Steven
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Christina Bulman
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, Unites States
| | - Emma Gunderson
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, Unites States
| | - Ian Vogel
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, Unites States
| | - Marianne Koschel
- Department of Immunology and Parasitology, Institute for Medical Microbiology, University Hospital Bonn, Bonn, Germany
| | - Alexandra Ehrens
- Department of Immunology and Parasitology, Institute for Medical Microbiology, University Hospital Bonn, Bonn, Germany
| | - Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, Unites States
| | - Denis Voronin
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, Unites States
| | - Nancy Tricoche
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, Unites States
| | - Achim Hoerauf
- Department of Immunology and Parasitology, Institute for Medical Microbiology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Marc P. Hübner
- Department of Immunology and Parasitology, Institute for Medical Microbiology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, Unites States
| | - Ghaith Aljayyoussi
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Jessica Dagley
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - David W. Hong
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Paul O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Steven A. Ward
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mark J. Taylor
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Joseph D. Turner
- Department of Tropical Disease Biology, Centre for Drugs and Diagnostics, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Chen Y, Huang X, Guo Z, Zhang J, Zhang L, Dai R. Study of Pharmacokinetics for Ivermectin B1a from Beagle Dogs. J Chromatogr Sci 2023:bmad092. [PMID: 38134186 DOI: 10.1093/chromsci/bmad092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023]
Abstract
Ivermectin has been widely used for antiparasitic drug, and has recently shown a broad-spectrum antiviral activity, including anti-Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the pharmacokinetic property of ivermectin has not been fully investigated yet. During the plasma preparation, ~32-46% of ivermectin was found in the precipitation. An Liquid Chromatograph-Mass Spectrometer (LC-MS/MS) method for ivermectin in the whole blood samples from beagle dogs was developed and validated. The specificity, accuracy, precision (intra-day and inter-day), matrix effect, recovery and stability of analyte reported here are satisfied with the criteria of Food and Drug Administration (FDA)-Bioanalysis guideline. The oral administrations pharmacokinetics of ivermectin in beagle dogs under fasting and after high-fat meal were studied, and the following parameters were obtained: fasting Cmax, 104 ± 35 μg·L-1; area under the concentration-time curve (AUC0-∞), 2,555 ± 941 h·μg·L-1; and high-fat meal Cmax, 147 ± 35 μg·L-1; AUC0-∞, 4,198 ± 1,279 h·μg·L-1. When the P-gp inhibitor curcumin was also coadministrated orally, Cmax and AUC0-∞ were found to be 177 ± 57 and 4,213 ± 948 h·μg·L-1, respectively. With the comparison to fasting treatment, coadministration of P-gp inhibitor curcumin resulted in increase of the exposure of ivermectin by 1.6-fold, while the exposure after the high-fat diet versus fasting was increased approximately in 1.4-fold, indicating that alternative absorption might play an important role for increasing the exposure of ivermectin for future clinic applications.
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Affiliation(s)
- Yuyang Chen
- School of Pharmacy, Guangzhou Medical University, Xinzao, Panyu District, Guangzhou, Guangdong 511436, China
| | - Xiaofang Huang
- Guangdong Ruigu Biotech Corporation, 18 Chuangxing Road, High-tech Zone, Qingyuan, Guangdong 511517, China
| | - Zizheng Guo
- Guangdong Ruigu Biotech Corporation, 18 Chuangxing Road, High-tech Zone, Qingyuan, Guangdong 511517, China
| | - Jingyu Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Xuhui District, Shanghai 200237, China
| | - Lixin Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Xuhui District, Shanghai 200237, China
| | - Renke Dai
- School of Pharmacy, Guangzhou Medical University, Xinzao, Panyu District, Guangzhou, Guangdong 511436, China
- Guangdong Ruigu Biotech Corporation, 18 Chuangxing Road, High-tech Zone, Qingyuan, Guangdong 511517, China
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Hadermann A, Jada SR, Sebit WJ, Deng T, Bol YY, Siewe Fodjo JN, De Coninck L, Matthijnssens J, Mertens I, Polman K, Colebunders R. Onchocerciasis-associated epilepsy: an explorative case-control study with viral metagenomic analyses on Onchocerca volvulus. F1000Res 2023; 12:1262. [PMID: 38439783 PMCID: PMC10911407 DOI: 10.12688/f1000research.138774.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/06/2023] [Indexed: 03/06/2024] Open
Abstract
Background A high prevalence of onchocerciasis-associated epilepsy (OAE) has been observed in onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission. However, the pathogenesis of OAE remains to be elucidated. We hypothesise that the O. volvulus virome could be involved in inducing epilepsy. With this study, we aim to describe the O. volvulus virome and identify potential neurotropic viruses linked to OAE. Methods In Maridi County, an onchocerciasis endemic area in South Sudan with a high prevalence of OAE, we will conduct an exploratory case-control study enrolling 40 persons aged 12 years and above with palpable onchocerciasis nodules. Cases will be participants with OAE (n=20), who will be age- and village-matched with controls without epilepsy (n=20). For each study participant, two skin snips at the iliac crest will be obtained to collect O. volvulus microfilariae, and one nodulectomy will be performed to obtain adult worms. A viral metagenomic study will be conducted on microfilariae and adult worms, and the O. volvulus virome of persons with and without OAE will be compared. The number, size, and localisation of onchocerciasis nodules in persons with and without OAE will be described. Moreover, the pre- and post-nodulectomy frequency of seizures in persons with OAE will be compared. Ethics and dissemination The protocol has been approved by the Ethics Committee of the University of Antwerp and the Ministry of Health of South Sudan. Findings will be disseminated nationally and internationally via meetings and peer-reviewed publications. Registration ClinicalTrials.gov registration NCT05868551 ( https://clinicaltrials.gov/study/NCT05868551). Protocol version 1.1, dated 09/05/2023.
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Affiliation(s)
- Amber Hadermann
- Global Health Institute, University of Antwerp, Antwerp, 2610, Belgium
| | | | - Wilson J. Sebit
- Public Health Laboratory, Ministry of Health South Sudan, Juba, South Sudan
| | | | - Yak Y. Bol
- Neglected Tropical Diseases Unit, Ministry of Health South Sudan, Juba, South Sudan
| | | | - Lander De Coninck
- Laboratory of Viral Metagenomics, KU Leuven, Leuven, Flanders, 3000, Belgium
| | - Jelle Matthijnssens
- Laboratory of Viral Metagenomics, KU Leuven, Leuven, Flanders, 3000, Belgium
| | - Inge Mertens
- Health Unit, VITO (Vlaamse Instelling voor Technologisch Onderzoek), Mol, 2400, Belgium
- Centre for Proteomics, University of Atwerp, Antwerp, Belgium
| | - Katja Polman
- Department of Health Sciences, VU Amsterdam, Amsterdam, 1081, The Netherlands
- Department Public Health, Institute of Tropical Medicine, Antwerp, 2600, Belgium
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Kamtsap P, Archile P, Flore N, Njiokou F, Renz A. Testing the susceptibility of larval stages of Simulium to temephos and Bacillus thuringiensis var israelensis in Germany and Northern Cameroon. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:286-299. [PMID: 36571295 DOI: 10.1111/mve.12630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 11/21/2022] [Indexed: 05/18/2023]
Abstract
Assays to evaluate the susceptibility of Simulium larvae to temephos and Bacillus thuringiensis var israelensis (Bti) were carried out by setting-up an in vitro laboratory test ('bio assay') and a semi-natural test ('système de goutières') to assess the LC50/LC90 values. Larvae of Simulium species in Cameroon (S. damnosum s.l., S. hargreavesi, S. vorax and S. cervicornutum) and (S. (Odagmia) ornatum and S. latipes) in Germany were identified and tested. In the bio-assay, 50 larvae were exposed for 10 min to concentrations from 0.01 to 10 ppm. For the Simulium from Germany, the LC50 (LC90) values after 3 and 6 h were 3.1 (27.9) and 0.14 (1.26) ppm for temephos and for Bti 7.8 (70.2) and 1.7 (15.3) ppm, respectively. For Cameroonian species, the values of LC50 (LC90) were lower, that is, 0.42 (8.04), 0.14 (2.70) and 0.073 (1.38) ppm, respectively, after 3, 6 and 12 h for temephos. In a semi natural condition, the LC50 of 10 min of application of temephos was 0.84 ppm after 3 h and a working solution (2.6 L) of Bti killed 50% after 6 h. To detect an upcoming of any resistance as it happened in Ivory Coast, a study of the occurrence resistance genes should be implemented.
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Affiliation(s)
- Pierre Kamtsap
- Department of Comparative Zoology, Institute of Evolution and Ecology, University of Tübingen, Tübingen, Germany
- Faculty of Science, Department of Cellular and Molecular Parasitology, University of Buea, Buea, Cameroon
- Programme Onchocercoses field station, University of Tübingen, Ngaoundéré, Cameroon
| | - Paguem Archile
- Programme Onchocercoses field station, University of Tübingen, Ngaoundéré, Cameroon
- Faculty of Agriculture and Veterinary Medicine, Department Veterinary Medicine, University of Buea, Buea, Cameroon
| | - Nguemaïm Flore
- Faculty of Health Sciences, University of Bamenda, Bambili, Cameroon
| | - Flobert Njiokou
- Laboratoire de Biologie Générale, Université de Yaoundé I, Yaoundé, Cameroon
| | - Alfons Renz
- Department of Comparative Zoology, Institute of Evolution and Ecology, University of Tübingen, Tübingen, Germany
- Programme Onchocercoses field station, University of Tübingen, Ngaoundéré, Cameroon
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Furtado JM, Fernandes AG, Silva JC, Del Pino S, Hommes C. Indigenous Eye Health in the Americas: The Burden of Vision Impairment and Ocular Diseases. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3820. [PMID: 36900846 PMCID: PMC10000964 DOI: 10.3390/ijerph20053820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/13/2023] [Accepted: 02/18/2023] [Indexed: 06/18/2023]
Abstract
Review of the burden of vision impairment and blindness and ocular disease occurrence in Indigenous Peoples of the Americas. We systematically reviewed findings of the frequency of vision impairment and blindness and/or frequency of ocular findings in Indigenous groups. The database search yielded 2829 citations, of which 2747 were excluded. We screened the full texts of 82 records for relevance and excluded 16. The remaining 66 articles were examined thoroughly, and 25 presented sufficient data to be included. Another 7 articles derived from references were included, summing a total of 32 studies selected. When considering adults over 40 years old, the highest frequencies of vision impairment and blindness in Indigenous Peoples varied from 11.1% in high-income North America to 28.5% in tropical Latin America, whose rates are considerably higher than those in the general population. Most of the ocular diseases reported were preventable and/or treatable, so blindness prevention programs should focus on accessibility to eye examinations, cataract surgeries, control of infectious diseases, and spectacles distribution. Finally, we recommend actions in six areas of attention towards improving the eye health in Indigenous Peoples: access and integration of eye services with primary care; telemedicine; customized propaedeutics; education on eye health; and quality of data.
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Affiliation(s)
- João Marcello Furtado
- Pan American Health Organization, Washington, DC 20037, USA
- Division of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14015-010, Brazil
| | - Arthur Gustavo Fernandes
- Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Sao Paulo 04023-062, Brazil
- Department of Anthropology and Archaeology, University of Calgary, Calgary, AB T2N 4N1, Canada
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Shey RA, Ghogomu SM, Nebangwa DN, Shintouo CM, Yaah NE, Yengo BN, Nkemngo FN, Esoh KK, Tchatchoua NMT, Mbachick TT, Dede AF, Lemoge AA, Ngwese RA, Asa BF, Ayong L, Njemini R, Vanhamme L, Souopgui J. Rational design of a novel multi-epitope peptide-based vaccine against Onchocerca volvulus using transmembrane proteins. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.1046522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Almost a decade ago, it was recognized that the global elimination of onchocerciasis by 2030 will not be feasible without, at least, an effective prophylactic and/or therapeutic vaccine to complement chemotherapy and vector control strategies. Recent advances in computational immunology (immunoinformatics) have seen the design of novel multi-epitope onchocerciasis vaccine candidates which are however yet to be evaluated in clinical settings. Still, continued research to increase the pool of vaccine candidates, and therefore the chance of success in a clinical trial remains imperative. Here, we designed a multi-epitope vaccine candidate by assembling peptides from 14 O. volvulus (Ov) proteins using an immunoinformatics approach. An initial 126 Ov proteins, retrieved from the Wormbase database, and at least 90% similar to orthologs in related nematode species of economic importance, were screened for localization, presence of transmembrane domain, and antigenicity using different web servers. From the 14 proteins retained after the screening, 26 MHC-1 and MHC-II (T-cell) epitopes, and linear B-lymphocytes epitopes were predicted and merged using suitable linkers. The Mycobacterium tuberculosis Resuscitation-promoting factor E (RPFE_MYCTU), which is an agonist of TLR4, was then added to the N-terminal of the vaccine candidate as a built-in adjuvant. Immune simulation analyses predicted strong B-cell and IFN-γ based immune responses which are necessary for protection against O. volvulus infection. Protein-protein docking and molecular dynamic simulation predicted stable interactions between the 3D structure of the vaccine candidate and human TLR4. These results show that the designed vaccine candidate has the potential to stimulate both humoral and cellular immune responses and should therefore be subject to further laboratory investigation.
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12
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Isiyaku S, Igbe M, Madaki S, Hamill LC, Ndongmo P, Adamani W, Bush S, Shu'aibu J, Elhassan E, Saka Y, Anyaike C, Akpan NM, Joel A, Nyior A, Abdullahi A, Aleiro A, Labbo A, Mafuyai HB, Nwoke BEB. The interruption of transmission of onchocerciasis in Kaduna, Kebbi and Zamfara states, Nigeria: another milestone achievement. Int Health 2022; 14:ii43-ii54. [PMID: 36130252 PMCID: PMC9492257 DOI: 10.1093/inthealth/ihac036] [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: 12/15/2021] [Revised: 02/02/2022] [Accepted: 05/12/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND More than 40 million people live in onchocerciasis-endemic areas in Nigeria. For at least 19 y, mass drug administration (MDA) with ivermectin was implemented with at least 65% total population coverage in Kaduna, Kebbi and Zamfara states. Impact surveys done using skin biopsies yielded no infections. Serological and entomological assessments were undertaken to determine if onchocerciasis transmission had been interrupted and MDA could be stopped. METHODS The presence of onchocerciasis-specific immunoglobulin G4 antibody was measured by enzyme=linked immunosorbent assay conducted on dried blood spots collected from 5- to 9-year-old children resident in each state. O-150 polymerase chain reaction testing of Simulium damnosum s.l. heads for Onchocerca volvulus DNA was done on black flies collected by human landing capture and Esperanza window traps. RESULTS A total of 9078 children were surveyed across the three states. A total of 6139 vectors were collected from Kaduna state, 129 from Kebbi state and 2 from Zamfara state; all were negative. Kebbi and Zamfara states did thousands of hours of black fly catching and intensive river prospecting. The resulting low fly catch was due to a low fly population incapable of sustaining transmission. CONCLUSION Onchocerciasis transmission has been interrupted and the three states meet World Health Organization thresholds: seropositivity in children <0.1% and <1/2000 infective black flies with 95% confidence. The 2.2 million people in Kaduna state and 4 million in Kebbi and Zamfara states no longer need ivermectin for onchocerciasis.
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Affiliation(s)
- Sunday Isiyaku
- Sightsavers, Golf Course Road, P.O. Box 503, Kaduna, Nigeria
| | - Michael Igbe
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
| | - Suzie Madaki
- Sightsavers, Golf Course Road, P.O. Box 503, Kaduna, Nigeria
| | - Louise C Hamill
- Sightsavers, 35 Perrymount Road, Haywards Heath, RH16 3BZ, UK
| | - Patrick Ndongmo
- Sightsavers, Derriere Laboratoire Meka, Bastos, Yaoundé, BP 4484, Cameroon
| | - William Adamani
- Sightsavers, Golf Course Road, P.O. Box 503, Kaduna, Nigeria
| | - Simon Bush
- Sightsavers, 35 Perrymount Road, Haywards Heath, RH16 3BZ, UK
| | - Joy Shu'aibu
- Sightsavers, Golf Course Road, P.O. Box 503, Kaduna, Nigeria
| | | | - Yisa Saka
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
| | - Chukwuma Anyaike
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
| | - Nse Michael Akpan
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
| | - Akilah Joel
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
| | - Audrey Nyior
- Federal Ministry of Health, Abuja, FCT, Nigeria, P.M.B. 083, Garki Abuja, Nigeria
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Knowledge, Attitude, and Preventive Practice Related to Onchocerciasis and Associated Factors among Resource-Limited Selamogo Woreda Residents, South West Ethiopia, 2021. J Trop Med 2022; 2022:2481841. [PMID: 36072827 PMCID: PMC9444457 DOI: 10.1155/2022/2481841] [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: 05/10/2022] [Revised: 07/15/2022] [Accepted: 08/09/2022] [Indexed: 11/30/2022] Open
Abstract
Introduction Ethiopians work very hard to control and eradicate the vector and the parasite of Onchocerciasis. However, some hard-to-reach areas are not adequately covered by interventions that have previously taken place in various endemic sites in the country. This study aimed to assess knowledge, attitude, and preventive practice of Onchocerciasis among Selamogo residents to enhance the expansion of interventions. Methods We used a survey questionnaire to capture the data on 572 Selamago residents. We checked, cleaned, entered the data into EPI Info v.7, and analyzed it in STATA v.15. We fitted a binary logistic regression model to examine the associated factors. Variables significant at P < 0.20 were included in the model. We declared association at P < 0.05. Results Of the 578 residents we approached, 572 (99%) responded to the interview. We found 48.30% of poor knowledge, 90.90% of poor attitude, and 85.70% preventive practice related to Onchocerciasis. Factors like Amhara ethnicity (AOR = 2.35, 95% CI: 1.05, 5.27), Orthodox Christianity (AOR = 1.87, 95% CI: 1.12, 3.10), Muslims (AOR = 2.28, 95% CI: 1.05, 4.94), secondary school (AOR = 2.31, 95% CI: 1.50, 3.55), diploma (AOR = 10.34, 95% CI: 4.62, 23.16), and preventability of Onchocerciasis (AOR = 3.02, 95% CI: 1.39, 6.55) were associated with KAP. Other factors like medical treatability, admission history to the health facilities, sex, and the number of households were also associated. Conclusion The KAP related to Onchocerciasis is very poor compared to the indicators and evidence in the country. An intervention that considers local resources like taking the experience of groups with good knowledge, attitude, and preventive practice led by educated plus positive attitude people regarding the preventability and treatability of Onchocerciasis might be mandatory to improve the status.
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Shrestha H, McCulloch K, Hedtke SM, Grant WN. Geospatial modeling of pre-intervention nodule prevalence of Onchocerca volvulus in Ethiopia as an aid to onchocerciasis elimination. PLoS Negl Trop Dis 2022; 16:e0010620. [PMID: 35849615 PMCID: PMC9333447 DOI: 10.1371/journal.pntd.0010620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 07/28/2022] [Accepted: 06/28/2022] [Indexed: 11/19/2022] Open
Abstract
Background Onchocerciasis is a neglected tropical filarial disease transmitted by the bites of blackflies, causing blindness and severe skin lesions. The change in focus for onchocerciasis management from control to elimination requires thorough mapping of pre-control endemicity to identify areas requiring interventions and to monitor progress. Onchocerca volvulus nodule prevalence in sub-Saharan Africa is spatially continuous and heterogeneous, and highly endemic areas may contribute to transmission in areas of low endemicity or vice-versa. Ethiopia is one such onchocerciasis-endemic country with heterogeneous O. volvulus nodule prevalence, and many districts are still unmapped despite their potential for onchocerciasis transmission. Methodology/Principle findings A Bayesian geostatistical model was fitted for retrospective pre-intervention nodule prevalence data collected from 916 unique sites and 35,077 people across Ethiopia. We used multiple environmental, socio-demographic, and climate variables to estimate the pre-intervention prevalence of O. volvulus nodules across Ethiopia and to explore their relationship with prevalence. Prevalence was high in southern and northwestern Ethiopia and low in Ethiopia’s central and eastern parts. Distance to the nearest river (RR: 0.9850, 95% BCI: 0.9751–0.995), precipitation seasonality (RR: 0.9837, 95% BCI: 0.9681–0.9995), and flow accumulation (RR: 0.9586, 95% BCI: 0.9321–0.9816) were negatively associated with O. volvulus nodule prevalence, while soil moisture (RR: 1.0218, 95% BCI: 1.0135–1.0302) was positively associated. The model estimated the number of pre-intervention cases of O. volvulus nodules in Ethiopia to be around 6.48 million (95% BCI: 3.53–13.04 million). Conclusions/Significance Nodule prevalence distribution was correlated with habitat suitability for vector breeding and associated biting behavior. The modeled pre-intervention prevalence can be used as a guide for determining priorities for elimination mapping in regions of Ethiopia that are currently unmapped, most of which have comparatively low infection prevalence. Areas with unknown onchocerciasis endemicity may pose a threat to eliminating transmission because they may re-introduce onchocerciasis to areas where interventions have been successful. Additionally, because vectors (and thus Onchocerca volvulus transmission) have specific ecological requirements for growth and development, changes in these ecological factors due to human activities (deforestation, modification of river flows by dam construction, climate change) might change patterns of parasite transmission and endemicity. To estimate the impact of environmental changes, we must first identify ecological factors determining prevalence. We have employed Bayesian geostatistical modeling to create a nationwide O. volvulus nodule prevalence map for Ethiopia based on pre-intervention nodule prevalence data and have explored the effect of environmental variables on nodule prevalence. We estimated the number of pre-intervention cases of nodules and associated uncertainty in previously unmapped areas of Ethiopia to identify areas that need additional data to increase the prediction accuracy. Hydrological variables such as distance to the nearest river, precipitation seasonality, soil moisture, and flow accumulation are associated significantly with O. volvulus nodule prevalence. We show that the spatial distribution of nodule prevalence can be estimated based on ecological data and that predicted prevalence can be used as a guide to prioritize pre-intervention mapping.
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Affiliation(s)
- Himal Shrestha
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
| | - Karen McCulloch
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
- WHO Collaborating Centre for Viral Hepatitis, Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital, and Department of Infectious Diseases, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Shannon M. Hedtke
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
- * E-mail:
| | - Warwick N. Grant
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
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Anagbogu IN, Saka YA, Surakat OA, Okoronkwo C, Davies E, Oyale P, Ekpo UF, Amazigo UV, Barbre K, Igbe M, Nyior A, Jacob SM, Gideon Nteun U, Abubakar Umar Z. Integrated transmission assessment surveys (iTAS) of lymphatic filariasis and onchocerciasis in Cross River, Taraba and Yobe States, Nigeria. Parasit Vectors 2022; 15:201. [PMID: 35698164 PMCID: PMC9195314 DOI: 10.1186/s13071-022-05302-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 04/26/2022] [Indexed: 12/01/2022] Open
Abstract
Background Integrated transmission assessment surveys (iTAS) have been recommended for evaluation of the transmission of both lymphatic filariasis (LF) and onchocerciasis as the prevalence of both diseases moves toward their respective elimination targets in Nigeria. Therefore, we conducted an iTAS between May and December 2017 in five local government areas (LGAs), also known as implementation units (IUs), in states of Cross River, Taraba and Yobe in Nigeria. Methods The TAS comprised two phases: the Pre-iTAS and the iTAS itself. Three states (Cross River, Taraba and Yobe), comprising five LGAs and 20 communities that have completed five rounds of combined treatment with ivermectin and albendazole for LF and 12 total rounds of ivermectin, were selected for inclusion in the study. All participants were tested with the Filariasis Test Strip (FTS; Alere Inc.) and the Biplex rapid Diagnostic Test (RDT; identifying filaria antigens Ov16/Wb123; Abbott diagnosctics Korea Inc.). Pre iTAS included 100 children ages 5-9 in each 4 communities and 300 individuals ages 10 and older in a subset of two communities. For the iTAS, only LGAs where antigenemia prevalence in all sampled communities during the Pre-iTAS was < 2% for LF were selected. Results Of the five LGAs included in the study, four met the cutoff of the Pre-iTAS and were included in the iTAS; the Ikom LGA was excluded from the iTAS due to antigenemia prevalence. A total of 11,531 school-aged children from 148 schools were tested for LF and onchocerciasis across these four LGAs, including 2873 children in Bade, 2622 children in Bekwara, 3026 children in Gashaka and 3010 children in Karim Lamido. Using the FTS, all samples from Bade and Karim Lamido were negative, whereas 0.2% of the samples from Bekwara and Gashaka were positive. Using the Biplex RDT, LF prevalence in Bade, Bekwara, Gashaka and Karim Lamido was < 0.1%, 0.5%, 0.4% and < 0.1%, respectively. Moreover, all samples from Bade and Karim Lamido were negative for onchocerciasis, whereas 3.1% and 1.8% of the samples from Bekwara and Gashaka were positive, respectively. Conclusion This study has provided additional information on the current burden of onchocerciasis and LF in the four IUs sampled where mass drug administration (MDA) for both infections has been ongoing for years. The study identifies that LF-MDA can be safely stopped in all four of the IUs studied, but that MDA for onchocerciasis needs to continue, even though this may pose a challenge for LF surveillance. Based on the preliminary results from all four sites, this study has fulfilled the primary objective of determining the programmatic feasibility of an iTAS as a tool to simultaneously assess onchocerciasis and LF prevalence in areas co-endemic for the two infections that have completed the recommended treatment for one or both infections, and to make decisions on how to proceed. Graphical Abstract ![]()
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Affiliation(s)
| | | | - Olabanji Ahmed Surakat
- Department of Zoology, Faculty of Basic and Applied Sciences, Osun State University, Osogbo, Nigeria.
| | | | | | | | - Uwem Friday Ekpo
- Department of Pure & Applied Zoology, Federal University of Agriculture, Abeokuta, Nigeria
| | - Uche V Amazigo
- African Programme for Onchocerciasis Control, Ouagadougou, Burkina Faso
| | - Kira Barbre
- Neglected Tropical Diseases Support Center, The Task Force for Global Health, Atlanta, GA, USA
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Idro R, Ogwang R, Barragan A, Raimondo JV, Masocha W. Neuroimmunology of Common Parasitic Infections in Africa. Front Immunol 2022; 13:791488. [PMID: 35222377 PMCID: PMC8866860 DOI: 10.3389/fimmu.2022.791488] [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: 10/08/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Parasitic infections of the central nervous system are an important cause of morbidity and mortality in Africa. The neurological, cognitive, and psychiatric sequelae of these infections result from a complex interplay between the parasites and the host inflammatory response. Here we review some of the diseases caused by selected parasitic organisms known to infect the nervous system including Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei spp., and Taenia solium species. For each parasite, we describe the geographical distribution, prevalence, life cycle, and typical clinical symptoms of infection and pathogenesis. We pay particular attention to how the parasites infect the brain and the interaction between each organism and the host immune system. We describe how an understanding of these processes may guide optimal diagnostic and therapeutic strategies to treat these disorders. Finally, we highlight current gaps in our understanding of disease pathophysiology and call for increased interrogation of these often-neglected disorders of the nervous system.
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Affiliation(s)
- Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Rodney Ogwang
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Programme, Nairobi, Kenya
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Joseph Valentino Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Willias Masocha
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
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17
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Ojekunle OZ, Esan RO, Balogun MA, Ademolu KO, Adegoke KA, Taiwo AM. Ecological assessment of Black Fly (Simuliumdamnosum, Sensulato) breeding sites in two tributaries of Ogun river, Ogun state, Nigeria. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:220. [PMID: 35201429 DOI: 10.1007/s10661-022-09770-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Onchocerciasis is a disease transmitted by blackfly vector of the genus Simuliumdamnosum complex having public and socio-economic consequences. The abundance of blackfly is directly linked to fluvial ecosystems in both tropical and non-tropical countries of the world. This study assessed the ecology of blackfly breeding sites in two tributaries of River Ogun located in Olokemeji and Lisa villages, Ogun State. A total of eighteen water samples were collected for physicochemical analysis during high rainfall (May, June and July), low rainfall (August, September and October) and dry season (November and December) with mean rainfall values of 163.17, 88.03 and 8.95 mm, respectively, in both tributaries. Physicochemical parameters such as temperature (oC), electrical conductivity (EC), pH, total solids (TS), dissolved oxygen (DO), biochemical oxygen demand (BOD), total suspended solids (TSS), hardness (H), sulphate (SO4), phosphate (PO4), alkalinity, acidity, nitrate (NO3) and total dissolved solids (TDS) were analysed using standard laboratory methods. Digestive enzymes were analysed using 1 g of frozen gut of Simulium larvae grounded with 20 ml of 0.067 g of potassium hydrogen and 20 ml of 0.1 M sodium reagent. A total of 766 and 482 samples of Simulium larvae were collected from Olokemeji and Lisa tributaries using Eppendorf tubes. The zooplanktons collected from Olokemeji and Lisa tributary were 904 and 802, while phytoplanktons collected from Olokemeji and Lisa tributary were 635 and 582 during the study period. Data obtained were analysed using both descriptive analysis and T-test. The results obtained for the physicochemical parameters were 28.7 °C, 137.5 µS/cm, 6.3, 248.1 mg/L, 58 mg/L, 108.8 mg/L, 90.8 mg/L, 2.24 mg/L, 2.24 mg/L, 30.76 mg/L, 42.35 mg/L, 1.99 mg/L, 2.07 mg/L and 2.55 mg/L for Temperature, EC, pH, TS, DO, BOD, TSS, H, SO4, PO4, alkalinity, acidity, NO3 and TDS, respectively. There were significant (p < 0.05) differences between the means of EC, pH, TS, TDS, TSS and hardness of Lisa tributary, and water samples were also viewed under an electron microscope for zooplanktons and phytoplanktons. The values of species diversity which were greater than 0.5 indicated that the species were abundant and evenly distributed. There were significant (p < 0.05) differences between the tributaries in all the digestive enzymes except amylase content. The regression analysis between TSS, nitrate, sulphate, phosphate, acidity, hardness, TS, pH and Simulium larvae abundance showed a positive correlation, R2 with values of 0.828, 0.994, 0.948, 0.933, 0.986, 0.997, 0.889 and 0.981, respectively. The R2 values between Simulium larvae abundance with phytoplanktons and rainfall have values of 0.868 at p < 0.01 and 0.911 at p < 0.05.
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Affiliation(s)
- Olusheyi Zaccheaus Ojekunle
- Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - Rotimi Olabode Esan
- Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - Mujeeb Adeyemi Balogun
- Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
- Faculty of Science and Technology, University of the Basque Country, Basque, Spain
- College of Science and Technology, University of Bordeaux, Bordeaux, France
- Faculty of Sciences, University of Liège, Liège, Belgium
| | - Kehinde O Ademolu
- Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - Kayode Adesina Adegoke
- Department of Chemical Sciences, University of Johannesburg, Johannesburg, South Africa.
| | - Adewale Matthew Taiwo
- Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
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18
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Abraham D, Graham-Brown J, Carter D, Gray SA, Hess JA, Makepeace BL, Lustigman S. Development of a recombinant vaccine against human onchocerciasis. Expert Rev Vaccines 2021; 20:1459-1470. [PMID: 34488533 DOI: 10.1080/14760584.2021.1977125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/02/2021] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Human onchocerciasis caused by the filarial nematode parasite Onchocerca volvulus remains a major cause of debilitating disease infecting millions primarily in Sub-Saharan Africa. The development of a prophylactic vaccine, along with mass drug administration, would facilitate meeting the goal of onchocerciasis elimination by 2030. AREAS COVERED Models used to study immunity to Onchocerca include natural infection of cattle with Onchocerca ochengi and O. volvulus infective third-stage larvae implanted within diffusion chambers in mice. A vaccine, comprised of two adjuvanted recombinant antigens, induced protective immunity in genetically diverse mice suggesting that it will function similarly in diverse human populations. These antigens were recognized by immune humans and also induced protective immunity against Brugia malayi. We describe the development of a fusion protein composed of the two vaccine antigens with the plan to test the vaccine in cows and non-human primates as a prelude to the initiation of phase 1 clinical trials. EXPERT OPINION The adjuvanted O. volvulus vaccine composed of two antigens Ov-103 and Ov-RAL-2 was shown to be consistently effective at inducing protective immunity using multiple immune mechanisms. The vaccine is ready for further evaluation in other animal models before moving to clinical trials in humans.
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Affiliation(s)
- David Abraham
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - John Graham-Brown
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
| | | | | | - Jessica A Hess
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Benjamin L Makepeace
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, USA
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19
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Raimon S, Lakwo TL, Sebit WJ, Siewe Fodjo JN, Alinda P, Carter JY, Post RJ, Colebunders R. "Slash and Clear", a Community-Based Vector Control Method to Reduce Onchocerciasis Transmission by Simulium sirbanum in Maridi, South Sudan: A Prospective Study. Pathogens 2021; 10:pathogens10101329. [PMID: 34684277 PMCID: PMC8538802 DOI: 10.3390/pathogens10101329] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 11/25/2022] Open
Abstract
Background: High ongoing Onchocerca volvulus transmission was recently documented in Maridi County, South Sudan. To complement community-directed treatment with ivermectin (CDTI) as the main onchocerciasis control strategy, we initiated a community-based vector control method “slash and clear” at the Maridi dam, a Simulium damnosum s.l. breeding site, to reduce O. volvulus transmission. Methods: Simulium damnosum s.l. biting rates were collected before and during the twenty months following the “slash and clear” intervention using the human landing catches. Black flies were dissected to measure parity rates before and twelve months after the intervention. Larvae and pupae of S. damnosum s.l. were collected from the dam for morphological and chromosomal characterization to identify the cytospecies involved. Results: Biting rates of S. damnosum s.l. close to the Maridi dam spillway decreased by >90% post-“slash and clear” for more than six months. Twelve months after the “slash and clear” intervention, the reduction in biting rates was still at <50% (p = 0.0007). Parity rates reduced from 13% pre-“slash and clear” (November 2019) to 5.6% post-“slash and clear” (November 2020). Larvae collected from the dam were identified as Simulium sirbanum. Conclusion: The “slash and clear” method was found to be an effective and cheap community-based method to reduce black fly biting rates caused by S. sirbanum. When repeated at least annually together with a high CDTI coverage, this intervention has the potential to considerably accelerate onchocerciasis elimination.
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Affiliation(s)
| | - Tom L. Lakwo
- Vector Control Division, Ministry of Health, Kampala P.O. Box 1661, Uganda; (T.L.L.); (P.A.)
| | - Wilson John Sebit
- Public Health Laboratory, Ministry of Health, May Rd, Juba P.O. Box 30125, South Sudan;
| | | | - Peter Alinda
- Vector Control Division, Ministry of Health, Kampala P.O. Box 1661, Uganda; (T.L.L.); (P.A.)
| | - Jane Y. Carter
- Amref Health Africa Headquarters, Nairobi P.O. Box 27691-00506, Kenya;
| | - Rory J. Post
- Disease Control Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK;
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 5UG, UK
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium;
- Correspondence: ; Tel.: +32-4-8692-0149
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20
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Stolk WA, Blok DJ, Hamley JID, Cantey PT, de Vlas SJ, Walker M, Basáñez MG. Scaling-Down Mass Ivermectin Treatment for Onchocerciasis Elimination: Modeling the Impact of the Geographical Unit for Decision Making. Clin Infect Dis 2021; 72:S165-S171. [PMID: 33909070 PMCID: PMC8201558 DOI: 10.1093/cid/ciab238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background Due to spatial heterogeneity in onchocerciasis transmission, the duration of ivermectin mass drug administration (MDA) required for eliminating onchocerciasis will vary within endemic areas and the occurrence of transmission “hotspots” is inevitable. The geographical scale at which stop-MDA decisions are made will be a key driver in how rapidly national programs can scale down active intervention upon achieving the epidemiological targets for elimination. Methods We used 2 onchocerciasis models (EPIONCHO-IBM and ONCHOSIM) to predict the likelihood of achieving elimination by 2030 in Africa, accounting for variation in preintervention endemicity levels and histories of ivermectin treatment. We explore how decision making at contrasting geographical scales (community vs larger scale “project”) changes projections on populations still requiring MDA or transitioning to post-treatment surveillance. Results The total population considered grows from 118 million people in 2020 to 136 million in 2030. If stop-MDA decisions are made at project level, the number of people requiring treatment declines from 69–118 million in 2020 to 59–118 million in 2030. If stop-MDA decisions are made at community level, the numbers decline from 23–81 million in 2020 to 15–63 million in 2030. The lower estimates in these prediction intervals are based on ONCHOSIM, the upper limits on EPIONCHO-IBM. Conclusions The geographical scale at which stop-MDA decisions are made strongly determines how rapidly national onchocerciasis programs can scale down MDA programs. Stopping in portions of project areas or transmission zones would free up human and economic resources.
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Affiliation(s)
- Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - David J Blok
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jonathan I D Hamley
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, United Kingdom.,MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, United Kingdom
| | - Paul T Cantey
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, United Kingdom.,London Centre for Neglected Tropical Disease Research, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - María-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, United Kingdom.,MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, United Kingdom
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21
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Ta-Tang TH, Luz SLB, Crainey JL, Rubio JM. An Overview of the Management of Mansonellosis. Res Rep Trop Med 2021; 12:93-105. [PMID: 34079424 PMCID: PMC8163967 DOI: 10.2147/rrtm.s274684] [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: 04/01/2021] [Accepted: 04/30/2021] [Indexed: 02/02/2023] Open
Abstract
Mansonellosis is caused by three filarial parasite species from the genus Mansonella that commonly produce chronic human microfilaraemias: M. ozzardi, M. perstans and M. streptocerca. The disease is widespread in Africa, the Caribbean and South and Central America, and although it is typically asymptomatic it has been associated with mild pathologies including leg-chills, joint-pains, headaches, fevers, and corneal lesions. No robust mansonellosis disease burden estimates have yet been made and the impact the disease has on blood bank stocks and the monitoring of other filarial diseases is not thought to be of sufficient public health importance to justify dedicated disease management interventions. Mansonellosis´s Ceratopogonidae and Simuliidae vectors are not targeted by other control programmes and because of their small size and out-door biting habits are unlikely to be affected by interventions targeting other disease vectors like mosquitoes. The ivermectin and mebendazole-based mass drug administration (iMDA and mMDA) treatment regimens deployed by the WHO´s Elimination of Neglected Tropical Diseases (ESPEN) programme and its forerunners have, however, likely impacted significantly on the mansonellosis disease burden, principally by reducing the transmission of M. streptocerca in Africa. The increasingly popular plan of using iMDA to control malaria could also affect M. ozzardi parasite prevalence and transmission in Latin America in the future. However, a potentially far greater mansonellosis disease burden impact is likely to come from short-course curative anti-Wolbachia therapeutics, which are presently being developed for onchocerciasis and lymphatic filariasis treatment. Even if the WHO´s ESPEN programme does not choose to deploy these drugs in MDA interventions, they have the potential to dramatically increase the financial and logistical feasibility of effective mansonellosis management. There is, thus, now a fresh and urgent need to better characterise the disease burden and eco-epidemiology of mansonellosis so that effective management programmes can be designed, advocated for and implemented.
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Affiliation(s)
- Thuy-Huong Ta-Tang
- Malaria and NTDs Laboratory, National Centre of Tropical Medicine, Instituto de Salud Carlos III, Madrid, Spain
| | - Sergio L B Luz
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz, Manaus, Amazonas State, Brazil
| | - James L Crainey
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz, Manaus, Amazonas State, Brazil
| | - José M Rubio
- Malaria & Emerging Parasitic Diseases Laboratory, National Microbiology Center, Instituto de Salud Carlos III, Madrid, Spain
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22
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Vieri MK, Logora MY, Rafiq K, Colebunders R. The World Health Organization road map for neglected tropical diseases 2021-2030: implications for onchocerciasis elimination programs. Infect Dis Poverty 2021; 10:70. [PMID: 34001286 PMCID: PMC8127298 DOI: 10.1186/s40249-021-00848-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/21/2021] [Indexed: 12/28/2022] Open
Abstract
In its new roadmap for neglected tropical diseases, the World Health Organization proposes three important strategic shifts: (i) Stronger accountability which shifting from process to impact indicators; (ii) Intensified cross-cutting approaches; and (iii) Stronger country ownership. In this paper we discuss the implementation of these three strategies in the setting of a high onchocerciasis disease burden in South Sudan. ![]()
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Affiliation(s)
- Melissa Krizia Vieri
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610, Antwerp, Belgium.
| | - Makoy Yibi Logora
- Neglected Tropical Diseases Unit, Ministry of Health, Juba, Republic of South Sudan
| | - Kamran Rafiq
- The International Society for Neglected Tropical Diseases, London, UK
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610, Antwerp, Belgium.
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23
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Onchocerciasis Prevalence among Persons with Epilepsy in an Onchocerciasis Hypo-Endemic Area in the Democratic Republic of Congo: A Cross-Sectional Study. Pathogens 2021; 10:pathogens10040389. [PMID: 33805016 PMCID: PMC8063918 DOI: 10.3390/pathogens10040389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/17/2022] Open
Abstract
A high epilepsy prevalence has been reported in onchocerciasis meso- and hyper-endemic regions in sub-Saharan Africa, including in the Democratic Republic of Congo (DRC). We investigated whether onchocerciasis-associated epilepsy can also be suspected in onchocerciasis hypo-endemic regions. Stored serum samples from 342 patients admitted with recent onset neurological symptoms admitted to Mosango general hospital, in the Kwilu province, DRC, between 2012 and 2015 were screened for onchocerciasis (OV16) antibodies by ELISA and Taenia solium antigen (using an in-house B158/B60 antigen test). Eighty-one (23.7%; 95% CI 19.5-28.5%) of these samples were positive for OV16 antibodies and 43/340 (12.6%; 95% CI 9.5-16.6%) were positive for T. solium antigen. Of the 58 persons clinically diagnosed with late onset epilepsy of unknown etiology, 19 (32.8%) were OV16 positive and nine (16%) T. solium antigen positive. In total, 16 persons with epilepsy were OV16 positive and T. solium negative, of whom 12 (75%) were between the ages seven to 31 years old, an age rage in which onchocerciasis-associated epilepsy is observed. Our study suggests that in onchocerciasis hypo-endemic areas, in T. solium antigen negative persons with epilepsy, onchocerciasis should be considered as a potential trigger of epilepsy.
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