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Ouedraogo MO, Meda IB, Kourouma K, Wienne FY, Nare D, Bougouma C, Compaore J, Kouanda S. Effects of Five Years of Treatment of Onchocerciasis with Ivermectin under Community Guidelines in Resurgent Areas of Burkina Faso: A before-and-after Analysis. Trop Med Infect Dis 2024; 9:207. [PMID: 39330896 PMCID: PMC11435634 DOI: 10.3390/tropicalmed9090207] [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: 08/08/2024] [Revised: 08/29/2024] [Accepted: 09/05/2024] [Indexed: 09/28/2024] Open
Abstract
BACKGROUND Almost the entire country of Burkina Faso was endemic to onchocerciasis. Onchocerciasis control efforts thus brought the prevalence of O. volvulus to a level where the disease was no longer a public health problem in 2002. A resurgence of onchocerciasis cases has been observed in two regions (Cascades and the Southwest) located around several river basins in 2010-2011. In accordance with WHO guidelines for the management of resurgent cases, community-directed treatment with ivermectin (CDTI) was implemented in the affected areas. The aim of this study was to determine the effects of this intervention on parasitological indices of onchocerciasis, depending on the distance between villages and rivers. METHODOLOGY We conducted a paired pre-post study using aggregated village-level data from two cross-sectional surveys conducted in each region. A Wilcoxon signed-rank test was used to compare the standardized microfilarodermia prevalence and community microfilarial load (CMFL). RESULTS A total of 43 villages in 6 health districts, in the Southwest (18) and Cascades (25) regions were included in the study. The key findings were that standardized microfilaria prevalence and CMFL decreased significantly after the implementation of CDTI in both regions (p < 0.0001). The median standardized microfilaria prevalence was 2.8 [interquartile range (IQR): 0.2-6.6] before CDTI and 0.72 [IQR: 0.0-2.17] after CDTI. The results showed also a decline in standardized microfilaria prevalence and CMFL in all villages, regardless of the distance separating the village from the streams. However, the results were not statistically significant for the villages located 5 km or more from streams (p = 0.0816 and 0.0542 for standardized microfilaria prevalence and CMFL, respectively). CONCLUSION Our results thus show that the implementation of effective CDTI could stop the transmission of O. volvulus in these two regions. The main challenge for stopping transmission could be the migration of populations to neighboring countries and migration of the vector from one country to another, as Burkina Faso shares some river basins with neighboring countries.
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Affiliation(s)
- Micheline O. Ouedraogo
- Helen Keller International, Ouagadougou 06 P.O. Box 9515, Burkina Faso; (F.Y.W.); (D.N.)
| | - Ivlabèhirè Bertrand Meda
- African Institute of Public Health (IASP), Ouagadougou 12 P.O. Box 199, Burkina Faso; (I.B.M.); (S.K.)
| | - Karifa Kourouma
- National Center for Training and Research in Rural Health of Maferinyah (CNFRSR), Maferinyah P.O. Box 2649, Guinea;
| | - Fanny Yago Wienne
- Helen Keller International, Ouagadougou 06 P.O. Box 9515, Burkina Faso; (F.Y.W.); (D.N.)
| | - Dieudonné Nare
- Helen Keller International, Ouagadougou 06 P.O. Box 9515, Burkina Faso; (F.Y.W.); (D.N.)
| | - Clarisse Bougouma
- National Program for the Control of Neglected Tropical Diseases, Ouagadougou 06 P.O. Box 9515, Burkina Faso; (C.B.); (J.C.)
| | - Justin Compaore
- National Program for the Control of Neglected Tropical Diseases, Ouagadougou 06 P.O. Box 9515, Burkina Faso; (C.B.); (J.C.)
| | - Seni Kouanda
- African Institute of Public Health (IASP), Ouagadougou 12 P.O. Box 199, Burkina Faso; (I.B.M.); (S.K.)
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Woromogo SH, Garoua-Adjou SI, Ngouyombo AD, Doyama-Woza RH, Diemer HSC, Longo JDD. Factors Associated With Coverage in Community-directed Treatment With Ivermectin for Onchocerciasis Control in Savanah and Forest Areas in Central African Republic: A Cross-sectional Study. J Prev Med Public Health 2024; 57:490-498. [PMID: 39139093 DOI: 10.3961/jpmph.24.280] [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: 06/07/2024] [Accepted: 08/01/2024] [Indexed: 08/15/2024] Open
Abstract
OBJECTIVES The aim of this study was to identify factors associated with coverage in community-directed treatment with ivermectin for onchocerciasis control in savannah and forest areas in the Central African Republic. METHODS A cross-sectional study was conducted in 2 districts where onchocerciasis is endemic. We employed a pretested and validated questionnaire that included questions about the socio-demographic characteristics of the respondents and variables relevant to coverage assessment. Multivariate logistic regression analyses were performed to identify the associations between surveyed mass drug administration (MDA) coverage and the variables considered, while accounting for potential confounding factors. A p-value <0.05 was considered statistically significant. RESULTS At the district level, the MDA program achieved a reach of 87.29% (95% confidence interval [CI], 86.03 to 88.55) in Bossangoa and 61.74% (95% CI, 59.56 to 63.92) in Kémo, compared to the reported rates of 90.02% and 91.70%, respectively. Women in both Bossangoa and Kémo were 1.28 times more likely to have taken ivermectin than men (95% CI, 1.12 to 1.47; p=0.008; 95% CI, 1.09 to 2.00; p=0.041, respectively). The age groups of 5-14, 15-24, and 25-34 were statistically associated with better distribution coverage in both districts. Individuals with knowledge of onchocerciasis were more likely to receive ivermectin compared to those without knowledge, with adjusted odds ratios of 1.41 (95% CI, 1.11 to 2.01; p=0.030) and 3.19 (95% CI, 2.91 to 4.08; p=0.001), respectively. CONCLUSIONS The authors recommend implementing measures to improve MDA coverage in future campaigns. These measures should include allocating sufficient time for MDA activities, providing health education, and mobilising the entire population.
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Affiliation(s)
- Sylvain Honoré Woromogo
- Doctoral School of Human and Veterinary Sciences, University of Bangui, Bangui, Central African Republic
- Department of Public Health, Faculty of Health Sciences, University of Bangui, Bangui, Central African Republic
| | | | - Ange Donatien Ngouyombo
- Doctoral School of Human and Veterinary Sciences, University of Bangui, Bangui, Central African Republic
| | - Rodrigue Herman Doyama-Woza
- Department of Public Health, Faculty of Health Sciences, University of Bangui, Bangui, Central African Republic
| | - Henri Saint Calvaire Diemer
- Department of Public Health, Faculty of Health Sciences, University of Bangui, Bangui, Central African Republic
| | - Jean de Dieu Longo
- Department of Public Health, Faculty of Health Sciences, University of Bangui, Bangui, Central African Republic
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Ityonzughul C, Sallau A, Miri E, Emukah E, Kahansim B, Adelamo S, Chiedo G, Ifeanyichukwu S, Coalson JE, Rakers L, Griswold E, Makata C, Oyediran F, Osuji S, Offor S, Obikwelu E, Otiji I, Richards FO, Noland GS. The Interruption of Transmission of Onchocerciasis in Abia, Anambra, Enugu, and Imo States, Nigeria: The Largest Global Onchocerciasis Stop-Treatment Decision to Date. Pathogens 2024; 13:671. [PMID: 39204271 PMCID: PMC11356909 DOI: 10.3390/pathogens13080671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 09/03/2024] Open
Abstract
Onchocerciasis causes severe morbidity in sub-Saharan Africa. Abia, Anambra, Enugu, and Imo states of Nigeria were historically classified meso- or hyperendemic and eligible for ivermectin mass drug administration (MDA). After ≥25 years of annual and biannual MDA, serological and entomological assessments were conducted to determine if Onchocerca volvulus transmission was interrupted. Dried blood spots collected in October 2020 from ≥3167 children 5-9 years old in each state were screened for O. volvulus-specific Ov16 antibody by enzyme-linked immunosorbent assay. Additionally, 52,187 Simulium damnosum heads (≥8845 per state) collected over 12 months between 2021 and 2022 were tested by pooled polymerase chain reaction (PCR) for O-150 DNA. Among seven seropositive children, four were found for follow-up skin snip PCR to confirm active infection. Three were negative and the fourth was excluded as he was visiting from an endemic state. The final seroprevalence estimates of each state had 95% upper confidence limits (UCL) < 0.1%. All fly pools were negative by O-150 PCR, giving a 95% UCL infective fly prevalence < 0.05% in each state. Each state therefore met the World Health Organization epidemiological and entomological criteria for stopping MDA effective January 2023. With 18.9 million residents eligible for MDA, this marked the largest global onchocerciasis stop-treatment decision to date.
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Affiliation(s)
- Cephas Ityonzughul
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Adamu Sallau
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Emmanuel Miri
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Emmanuel Emukah
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Barminas Kahansim
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Solomon Adelamo
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - George Chiedo
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Samuel Ifeanyichukwu
- The Carter Center, Jos 930104, Nigeria; (A.S.); (E.M.); (E.E.); (B.K.); (S.A.); (G.C.); (S.I.)
| | - Jenna E. Coalson
- The Carter Center, Atlanta, GA 30307, USA; (J.E.C.); (L.R.); (E.G.); (F.O.R.J.); (G.S.N.)
| | - Lindsay Rakers
- The Carter Center, Atlanta, GA 30307, USA; (J.E.C.); (L.R.); (E.G.); (F.O.R.J.); (G.S.N.)
| | - Emily Griswold
- The Carter Center, Atlanta, GA 30307, USA; (J.E.C.); (L.R.); (E.G.); (F.O.R.J.); (G.S.N.)
| | - Chukwuemeka Makata
- Federal Ministry of Health and Social Welfare, Abuja 900242, Nigeria; (C.M.); (F.O.)
| | - Fatai Oyediran
- Federal Ministry of Health and Social Welfare, Abuja 900242, Nigeria; (C.M.); (F.O.)
| | - Stella Osuji
- Imo State Ministry of Health, Owerri 460281, Nigeria;
| | - Solomon Offor
- Abia State Ministry of Health, Umuahia 440236, Nigeria;
| | | | - Ifeoma Otiji
- Enugu State Ministry of Health, Enugu 400105, Nigeria;
| | - Frank O. Richards
- The Carter Center, Atlanta, GA 30307, USA; (J.E.C.); (L.R.); (E.G.); (F.O.R.J.); (G.S.N.)
| | - Gregory S. Noland
- The Carter Center, Atlanta, GA 30307, USA; (J.E.C.); (L.R.); (E.G.); (F.O.R.J.); (G.S.N.)
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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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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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Njamnshi AK, Njamnshi WY, Siewe Fodjo JN. Onchocerciasis elimination in sub-Saharan Africa requires alternative strategies. Lancet Glob Health 2024; 12:e715-e716. [PMID: 38484746 DOI: 10.1016/s2214-109x(24)00089-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 04/15/2024]
Affiliation(s)
- Alfred K Njamnshi
- Brain Research Africa Initiative, Geneva, Switzerland; Brain Research Africa Initiative, Yaoundé, Cameroon; Neuroscience Lab, Faculty of Medicine and Biomedical Sciences, The University of Yaoundé I, Yaoundé, Cameroon.
| | - Wepnyu Y Njamnshi
- Brain Research Africa Initiative, Geneva, Switzerland; Brain Research Africa Initiative, Yaoundé, Cameroon; Neuroscience Lab, Faculty of Medicine and Biomedical Sciences, The University of Yaoundé I, Yaoundé, Cameroon; Division of Health Operations Research, Ministry of Public Health, Yaoundé, Cameroon
| | - Joseph N Siewe Fodjo
- Brain Research Africa Initiative, Yaoundé, Cameroon; Division of Health Operations Research, Ministry of Public Health, Yaoundé, Cameroon; Global Health Institute, University of Antwerp, Antwerp, Belgium
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Nikièma AS, Koala L, Post RJ, Kima A, Compaoré J, Kafando CM, Nana JB, Bougouma C, Faye B, Traoré S, Dabiré RK. Progress towards elimination of onchocerciasis in the Region du Sud-Ouest of Burkina Faso which was previously subject to a recrudescence event after vector control. PLoS Negl Trop Dis 2024; 18:e0012118. [PMID: 38683750 PMCID: PMC11057763 DOI: 10.1371/journal.pntd.0012118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 03/29/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND The Sud-Ouest region of Burkina Faso (especially the Bougouriba valley) has been historically problematic with respect to onchocerciasis control, with a recrudescence of infections after vector control carried out the WHO Onchocerciasis Control Programme was halted in 1989. After 1996, mass drug administration of ivermectin was instigated to control the recrudescence so that it would no longer constitute a public health problem. However, in 2010 WHO changed its recommended policy from control to elimination, and in 2013 biannual Community-Directed Treatment with Ivermectin (CDTI) was instigated. Epidemiological surveys were carried-out in 2011 and 2018 to determine whether CDTI was producing a decline in infection levels and progress towards elimination. METHODOLOGY/PRINCIPAL FINDINGS A cross-sectional study was conducted across 20 villages in four health districts in 2011 and 29 villages in 2018. Individuals aged five years and above were examined by skin-snip, and the prevalence and microfilarial load was determined for each village. In 2011, 75% of villages had some infections and 20% had prevalences >5%, with a mean prevalence across all villages of 2.63% (range 0.0-9.7%), and community microfilarial load ranging from 0 to 0.25 microfilariae per biopsy. In 2018, nine villages (= 31% of total) had some infections, with prevalences ranging from 0.41% to 3.54%, and a mean prevalence across all villages of 0.37%. Community microfilarial load ranged from 0 to 0.1. Amongst those people found to be microfilarial positive, 87% had a history of migration. CONCLUSIONS/SIGNIFICANCE The endemicity of onchocerciasis infection in the Sud-Ouest region has declined to low levels and seems to be progressing towards elimination. Our findings indicated that biannual CDTI is having good effect, but it should continue for a number of years to ensure elimination of transmission. However, progress towards elimination has a troublesome history in this region, and it would be advisable to select more sentinel villages to have confidence in any future epidemiological and entomological surveys, especially Stop-MDA surveys. With positive individuals migrating between countries, cross-border collaboration needs more attention to ensure effective treatment for onchocerciasis elimination.
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Affiliation(s)
- Achille Sindimbasba Nikièma
- Ministère de l’Enseignement Supérieur, de la Recherche et de l’Innovation, Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest (IRSS/Bobo-Dioulasso), Ouagadougou, Burkina Faso
- Université Cheikh Anta Diop, Dakar, Sénégal
| | - Lassane Koala
- Ministère de l’Enseignement Supérieur, de la Recherche et de l’Innovation, Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest (IRSS/Bobo-Dioulasso), Ouagadougou, Burkina Faso
| | - Rory J. Post
- School of Biological & Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Appolinaire Kima
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Justin Compaoré
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Claude M. Kafando
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Jean Baptiste Nana
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Clarisse Bougouma
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | | | - Soungalo Traoré
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Roch Kounbobr Dabiré
- Ministère de l’Enseignement Supérieur, de la Recherche et de l’Innovation, Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest (IRSS/Bobo-Dioulasso), Ouagadougou, Burkina Faso
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8
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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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9
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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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Kargbo-Labour I, Bah MS, Melchers NVSV, Conteh A, Redwood-Sawyerr V, Stolk WA, Paye J, Sonnie M, Veinoglou A, Koroma JB, Hodges MH, Weaver AM, Zhang Y. Impact assessment of onchocerciasis through lymphatic filariasis transmission assessment surveys using Ov-16 rapid diagnostic tests in Sierra Leone. Parasit Vectors 2024; 17:121. [PMID: 38468307 PMCID: PMC10926616 DOI: 10.1186/s13071-024-06198-5] [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: 09/05/2023] [Accepted: 02/15/2024] [Indexed: 03/13/2024] Open
Abstract
BACKGROUND Onchocerciasis is endemic in 14 of Sierra Leone's 16 districts with high prevalence (47-88.5%) according to skin snips at baseline. After 11 rounds of mass treatment with ivermectin with good coverage, an impact assessment was conducted in 2017 to assess the progress towards eliminating onchocerciasis in the country. METHODS A cluster survey was conducted, either integrated with lymphatic filariasis (LF) transmission assessment survey (TAS) or standalone with the LF TAS sampling strategy in 12 (now 14) endemic districts. Finger prick blood samples of randomly selected children in Grades 1-4 were tested in the field using SD Bioline Onchocerciasis IgG4 rapid tests. RESULTS In total, 17,402 children aged 4-19 years in 177 schools were tested, and data from 17,364 children aged 4-14 years (14,230 children aged 5-9 years) were analyzed. Three hundred forty-six children were confirmed positive for Ov-16 IgG4 antibodies, a prevalence of 2.0% (95% CI 1.8-2.2%) in children aged 4-14 years with prevalence increasing with age. Prevalence in boys (2.4%; 95% CI 2.1-2.7%) was higher than in girls (1.6%; 95% CI 1.4-1.9%). There was a trend of continued reduction from baseline to 2010. Using data from children aged 5-9 years, overall prevalence was 1.7% (95% CI 1.5-1.9%). The site prevalence ranged from 0 to 33.3% (median prevalence = 0.0%): < 2% in 127 schools, 2 to < 5% in 34 schools and ≥ 5% in 16 schools. There was a significant difference in average prevalence between districts. Using spatial analysis, the Ov-16 IgG4 antibody prevalence was predicted to be < 2% in coastal areas and in large parts of Koinadugu, Bombali and Tonkolili Districts, while high prevalence (> 5%) was predicted in some focal areas, centered in Karene, Kailahun and Moyamba/Tonkolili. CONCLUSIONS Low Ov-16 IgG4 antibody prevalence was shown in most areas across Sierra Leone. In particular, low seroprevalence in children aged 5-9 years suggests that the infection was reduced to a low level after 11 rounds of treatment intervention. Sierra Leone has made major progress towards elimination of onchocerciasis. However, attention must be paid to those high prevalence focal areas.
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Affiliation(s)
- Ibrahim Kargbo-Labour
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Natalie V S Vinkeles Melchers
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Social Sciences, Health and Society, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Abdulai Conteh
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jusufu Paye
- Helen Keller International, Freetown, Sierra Leone
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11
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Crawford KE, Hedtke SM, Doyle SR, Kuesel AC, Armoo S, Osei-Atweneboana MY, Grant WN. Genome-based tools for onchocerciasis elimination: utility of the mitochondrial genome for delineating Onchocerca volvulus transmission zones. Int J Parasitol 2024; 54:171-183. [PMID: 37993016 DOI: 10.1016/j.ijpara.2023.11.002] [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: 05/03/2023] [Revised: 09/21/2023] [Accepted: 11/13/2023] [Indexed: 11/24/2023]
Abstract
National programs in Africa have expanded their objectives from control of onchocerciasis (river blindness) as a public health problem to elimination of parasite transmission, motivated by the reduction of Onchocerca volvulus infection prevalence in many African meso- and hyperendemic areas due to mass drug administration of ivermectin (MDAi). Given the large, contiguous hypo-, meso-, and hyperendemic areas, sustainable elimination of onchocerciasis in sub-Saharan Africa requires delineation of geographic boundaries for parasite transmission zones, so that programs can consider the risk of parasite re-introduction through vector or human migration from areas with ongoing transmission when making decisions to stop MDAi. We propose that transmission zone boundaries can be delineated by characterising the parasite genetic population structure within and between potential zones. We analysed whole mitochondrial genome sequences of 189 O. volvulus adults to determine the pattern of genetic similarity across three West African countries: Ghana, Mali, and Côte d'Ivoire. Population genetic structure indicates that parasites from villages near the Pru, Daka, and Black Volta rivers in central Ghana belong to one parasite population, indicating that the assumption that river basins constitute individual transmission zones is not supported by the data. Parasites from Mali and Côte d'Ivoire are genetically distinct from those from Ghana. This research provides the basis for developing tools for elimination programs to delineate transmission zones, to estimate the risk of parasite re-introduction via vector or human movement when intervention is stopped in one area while transmission is ongoing in others, to identify the origin of infections detected post-treatment cessation, and to investigate whether persisting prevalence despite ongoing interventions in one area is due to parasites imported from others.
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Affiliation(s)
- Katie E Crawford
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia
| | - Shannon M Hedtke
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia; Department of Environment and Genetics, La Trobe University, Bundoora, Victoria, Australia.
| | - Stephen R Doyle
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia
| | - Annette C Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Samuel Armoo
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research, Council Close, Accra, Ghana
| | - Mike Y Osei-Atweneboana
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research, Council Close, Accra, Ghana
| | - Warwick N Grant
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia; Department of Environment and Genetics, La Trobe University, Bundoora, Victoria, Australia
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12
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Domche A, Nana Djeunga HC, Nwane PB, Njitchouang GR, Nono Fesuh B, Njiokou F, Jacob B, Pion SD, Kamgno J. Significant reduction of blackfly densities in persistent onchocerciasis area following pilot implementation of an environment friendly approach (Slash and Clear). Sci Rep 2024; 14:408. [PMID: 38172522 PMCID: PMC10764779 DOI: 10.1038/s41598-023-50747-4] [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: 07/10/2023] [Accepted: 12/24/2023] [Indexed: 01/05/2024] Open
Abstract
The effectiveness of the "Slash and Clear" method in reducing blackfly populations in low transmission areas is established, but its impact in high transmission settings with large rivers and dense vectors is yet to be proven. A community-based intervention study was conducted in the Mbam Valley, Centre Cameroon, involving two sites: Bayomen (control) and Biatsota (intervention). In each arm, baseline blackfly densities were collected over one year using the human landing method. The intervention consisted of destroying the trailing vegetation where blackflies breed. Blackfly densities were collected post-intervention to assess the impact of the intervention. Post-intervention data showed a 50.8% reduction in blackfly density in Biatsota (mean number of collected blackflies from 1936 to 953), while a reduction of 26.7% was observed in Bayomen (mean number of collected blackflies from 2418 to 1774). The reduction rate attributable to the intervention was 32.9%. Statistical analysis confirmed that the reduction in blackfly density was significantly greater in the intervention site. This study demonstrates the feasibility and significant impact of the "Slash and Clear" method in high transmission areas. However, further research is required to assess its long-term effects and determine how this strategy can be scaled up and sustained until onchocerciasis elimination is achieved.
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Affiliation(s)
- André Domche
- Higher Institute of Scientific and Medical Research (ISM), Yaoundé, Cameroon.
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.
| | | | - Philippe B Nwane
- Higher Institute of Scientific and Medical Research (ISM), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Guy R Njitchouang
- Higher Institute of Scientific and Medical Research (ISM), Yaoundé, Cameroon
| | - Betrand Nono Fesuh
- Higher Institute of Scientific and Medical Research (ISM), Yaoundé, Cameroon
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Benjamin Jacob
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Sébastien D Pion
- UMI 233 TransVIH MI, University of Montpellier, Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
| | - Joseph Kamgno
- Higher Institute of Scientific and Medical Research (ISM), Yaoundé, Cameroon
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13
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Doherty M, Grant JR, Pilotte N, Bennuru S, Fischer K, Fischer PU, Lustigman S, Nutman TB, Pfarr K, Hoerauf A, Unnasch TR, Hassan HK, Wanji S, Lammie PJ, Ottesen E, Mackenzie C, Williams SA. Optimized strategy for real-time qPCR detection of Onchocerca volvulus DNA in pooled Simulium sp. blackfly vectors. PLoS Negl Trop Dis 2023; 17:e0011815. [PMID: 38096317 PMCID: PMC10754622 DOI: 10.1371/journal.pntd.0011815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/28/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
BACKGROUND Onchocerca volvulus is a filarial parasite that is a major cause of dermatitis and blindness in endemic regions primarily in sub-Saharan Africa. Widespread efforts to control the disease caused by O. volvulus infection (onchocerciasis) began in 1974 and in recent years, following successful elimination of transmission in much of the Americas, the focus of efforts in Africa has moved from control to the more challenging goal of elimination of transmission in all endemic countries. Mass drug administration (MDA) with ivermectin has reached more than 150 million people and elimination of transmission has been confirmed in four South American countries, with at least two African countries having now stopped MDA as they approach verification of elimination. It is essential that accurate data for active transmission are used to assist in making the critical decision to stop MDA, since missing low levels of transmission and infection can lead to continued spread or recrudescence of the disease. METHODOLOGY/PRINCIPAL FINDINGS Current World Health Organization guidelines for MDA stopping decisions and post-treatment surveillance include screening pools of the Simulium blackfly vector for the presence of O. volvulus larvae using a PCR-ELISA-based molecular technique. In this study, we address the potential of an updated, practical, standardized molecular diagnostic tool with increased sensitivity and species-specificity by comparing several candidate qPCR assays. When paired with heat-stable reagents, a qPCR assay with a mitochondrial DNA target (OvND5) was found to be more sensitive and species-specific than an O150 qPCR, which targets a non-protein coding repetitive DNA sequence. The OvND5 assay detected 19/20 pools of 100 blackfly heads spiked with a single L3, compared to 16/20 for the O150 qPCR assay. CONCLUSIONS/SIGNIFICANCE Given the improved sensitivity, species-specificity and resistance to PCR inhibitors, we identified OvND5 as the optimal target for field sample detection. All reagents for this assay can be shipped at room temperature with no loss of activity. The qPCR protocol we propose is also simpler, faster, and more cost-effective than the current end-point molecular assays.
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Affiliation(s)
- Mary Doherty
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Jessica R. Grant
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Nils Pilotte
- Department of Biological Sciences, Quinnipiac University, Hamden, Connecticut, United States of America
| | - Sasisekhar Bennuru
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Kerstin Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Peter U. Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner-Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner-Site Bonn-Cologne, Bonn, Germany
| | - Thomas R. Unnasch
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida, United States of America
| | - Hassan K. Hassan
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida, United States of America
| | - Samuel Wanji
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment, Buea, Cameroon
| | - Patrick J. Lammie
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Eric Ottesen
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Charles Mackenzie
- NTD-SC, Task Force for Global Health, Atlanta, Georgia, United States of America
- RLMF, The END Fund, New York, New York, United States of America
| | - Steven A. Williams
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, United States of America
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Dolo H, Coulibaly ME, Sow M, Coulibaly YI, Doumbia M, Sangare M, Sanogo A, Dembele B, Guindo B, Coulibaly M, Keita M, Soumaoro L, Diarra D, Dicko B, Hamill L, Doumbia S, Sangho H, Sangare Y, Zhang Y, Tallant J, Yaro AS, Mackenzie C, Nutman TB, Boakye D. Progress towards elimination of onchocerciasis transmission in Mali: A "pre-stop MDA" survey in 18 transmission zones. PLoS Negl Trop Dis 2023; 17:e0011632. [PMID: 37967137 PMCID: PMC10686495 DOI: 10.1371/journal.pntd.0011632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/29/2023] [Accepted: 08/30/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Onchocerciasis control activities in Mali began in 1975 with vector larviciding carried out by the Onchocerciasis Control Programme (OCP), followed by the distribution of ivermectin from 1998 until the closure of the OCP in 2002. At that time, epidemiological evaluations, using skin snip microscopy and O-150 pool screening PCR in black flies, indicated that the disease had been largely controlled as a public health problem. Ivermectin distribution was nevertheless continued after 2002 in 34 of the 75 health districts in Mali as these were known to still be meso- or hyper-endemic for onchocerciasis. In addition, the onchocerciasis sites known to be hypo-endemic for onchocerciasis benefited from the distribution of ivermectin treatment as part of the mass drug administration (MDA) program for lymphatic filariasis. Various entomological and epidemiological evaluations have now indicated that Mali may have achieved successful interruption of onchocerciasis transmission. METHODS A series of cross-sectional surveys to update vector breeding sites throughout the endemic areas, followed by a pre-stop ivermectin mass drug administration (Pre-stop MDA) survey, were undertaken in 2019-2020. Based on breeding site findings, historical epidemiological assessments, and vector collection site maps, 18 operational transmission zones (OTZ) were delineated within which a total of 104 first line villages were selected for evaluation. Dried blood spots (DBS) samples were collected from 10,400 children (5-9 years old) from these 104 first line villages and processed for the presence of OV16 antibody using a lab-based rapid diagnostic test. RESULTS Within the 544 Simulium damnosum s.l. breeding sites visited in all five endemic onchocerciasis endemic regions of Mali 18.01% (98/544) were seen to be active with the presence of at least one stage of S. damnosum. The overall prevalence of OV16 positive children was 0.45% (47/10,400). However, two hotspots were identified: 2.60% (13/500) seroprevalence in the OTZ number 5 in Kayes Region and 1.40% (7/500) in the OTZ number 1 of Sikasso Region. CONCLUSION These data show that onchocerciasis prevalence in the five endemic regions has declined to levels that indicate that Stop-MDA surveys should be now carried out in most of the OTZ except for one in the Kayes Region. This latter site will need additional ivermectin treatment before reevaluation, and an OTZ in the Sikasso Region requires revaluation before possibly reinitiating MDA.
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Affiliation(s)
- Housseini Dolo
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
- Onchocerciasis Control Programme, National Health and Public Hygiene, Bamako, Mali
| | - Michel Emmanuel Coulibaly
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Moussa Sow
- Onchocerciasis Control Programme, National Health and Public Hygiene, Bamako, Mali
| | - Yaya Ibrahim Coulibaly
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Mama Doumbia
- Helen Keller International, Bamako, Mali and Dakar, Senegal
| | - Moussa Sangare
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Abdoul Sanogo
- Onchocerciasis Control Programme, National Health and Public Hygiene, Bamako, Mali
| | - Benoit Dembele
- Helen Keller International, Bamako, Mali and Dakar, Senegal
| | | | - Mamadou Coulibaly
- SightSavers International, Mali Country Office, Bamako, Mali, and UK Office, Haywards Heath, England, United Kingdom
| | - Modibo Keita
- Helen Keller International, Bamako, Mali and Dakar, Senegal
| | - Lamine Soumaoro
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Dansine Diarra
- Faculty of History and Geography, University of Social Sciences and Management of Bamako, Bamako, Mali
| | - Boubacar Dicko
- SightSavers International, Mali Country Office, Bamako, Mali, and UK Office, Haywards Heath, England, United Kingdom
| | - Louise Hamill
- SightSavers International, Mali Country Office, Bamako, Mali, and UK Office, Haywards Heath, England, United Kingdom
| | - Seydou Doumbia
- Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Hamadoun Sangho
- Neglected Tropical Diseases Research Unit, Faculty of Medicine and OdontoStomatology, USTTB, Bamako, Mali
| | - Yacouba Sangare
- Onchocerciasis Control Programme, National Health and Public Hygiene, Bamako, Mali
| | - Yaobi Zhang
- Helen Keller International, New York, New York State, United States of America
| | - Jamie Tallant
- The END Fund, Neglected Tropical Diseases, New York, New York State, United States of America
| | | | - Charles Mackenzie
- The END Fund, Neglected Tropical Diseases, New York, New York State, United States of America
- COR-NTD, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, NIH, Bethesda, Maryland, United States of America
| | - Daniel Boakye
- The END Fund, Neglected Tropical Diseases, New York, New York State, United States of America
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
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15
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Kura K, Milton P, Hamley JID, Walker M, Bakajika DK, Kanza EM, Opoku NO, Howard H, Nigo MM, Asare S, Olipoh G, Attah SK, Mambandu GL, Kennedy KK, Kataliko K, Mumbere M, Halleux CM, Hopkins A, Kuesel AC, Kinrade S, Basáñez MG. Can mass drug administration of moxidectin accelerate onchocerciasis elimination in Africa? Philos Trans R Soc Lond B Biol Sci 2023; 378:20220277. [PMID: 37598705 PMCID: PMC10440165 DOI: 10.1098/rstb.2022.0277] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/11/2023] [Indexed: 08/22/2023] Open
Abstract
Epidemiological and modelling studies suggest that elimination of Onchocerca volvulus transmission (EoT) throughout Africa may not be achievable with annual mass drug administration (MDA) of ivermectin alone, particularly in areas of high endemicity and vector density. Single-dose Phase II and III clinical trials demonstrated moxidectin's superiority over ivermectin for prolonged clearance of O. volvulus microfilariae. We used the stochastic, individual-based EPIONCHO-IBM model to compare the probabilities of reaching EoT between ivermectin and moxidectin MDA for a range of endemicity levels (30 to 70% baseline microfilarial prevalence), treatment frequencies (annual and biannual) and therapeutic coverage/adherence values (65 and 80% of total population, with, respectively, 5 and 1% of systematic non-adherence). EPIONCHO-IBM's projections indicate that biannual (six-monthly) moxidectin MDA can reduce by half the number of years necessary to achieve EoT in mesoendemic areas and might be the only strategy that can achieve EoT in hyperendemic areas. Data needed to improve modelling projections include (i) the effect of repeated annual and biannual moxidectin treatment; (ii) inter- and intra-individual variation in response to successive treatments with moxidectin or ivermectin; (iii) the effect of moxidectin and ivermectin treatment on L3 development into adult worms; and (iv) patterns of adherence to moxidectin and ivermectin MDA. This article is part of the theme issue 'Challenges in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Philip Milton
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Jonathan I. D. Hamley
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
| | - Didier K. Bakajika
- Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), African Regional Office of the World Health Organization (WHO/AFRO/ESPEN), Brazzaville, Democratic Republic of Congo
| | - Eric M. Kanza
- Programme Nationale de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive (PNLMTN-CTP), Ministère de la Santé Publique, Kinshasa, Democratic Republic of the Congo
| | - Nicholas O. Opoku
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Hayford Howard
- Liberia Institute for Biomedical Research (LIBR), Monrovia, Liberia
| | - Maurice M. Nigo
- Institut Supérieur des Techniques Médicales de Nyankunde, Bunia, Democratic Republic of the Congo
| | | | - George Olipoh
- Precious Minerals Marketing Company, National Assay Centre, Technical Department, Diamond House, Accra, GA-143-2548, Ghana
| | - Simon K. Attah
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, Accra, Ghana
| | - Germain L. Mambandu
- Inspection Provinciale de la Santé de la Tshopo, Kisangani, Democratic Republic of the Congo
| | - Kambale Kasonia Kennedy
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Kambale Kataliko
- Centre de Santé CECA 20 de Mabakanga, Beni, Nord Kivu, Democratic Republic of the Congo
| | - Mupenzi Mumbere
- Medicines Development for Global Health, 18 Kavanagh Street, Southbank, Victoria 3006, Australia
| | - Christine M. Halleux
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
| | - Adrian Hopkins
- Neglected and Disabling Diseases of Poverty Consultant, Gravesend, Kent DA11 OSL, UK
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
| | - Sally Kinrade
- Medicines Development for Global Health, 18 Kavanagh Street, Southbank, Victoria 3006, Australia
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
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16
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Moutongo Mouandza R, Mourou JR, Moutombi Ditombi B, Roger Sibi Matotou H, Ekomi B, Bouyou-Akotet MK, Mawili-Mboumba DP. Sociodemographics, Clinical Factors, and Biological Factors Associated with Loiasis in Endemic Onchocerciasis Areas in Southern Gabon. Am J Trop Med Hyg 2023; 109:850-857. [PMID: 37339766 PMCID: PMC10551092 DOI: 10.4269/ajtmh.22-0558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 04/22/2023] [Indexed: 06/22/2023] Open
Abstract
To implement the appropriate strategies for scale-up interventions to eliminate onchocerciasis without severe adverse events, clinical and biological factors associated with loiasis were analyzed in onchocerciasis-endemic areas. Blood was collected from volunteers after examination by a physician. Detection of microfilariae and measurement of Ov16 IgG4 were performed using direct microscopic examination of blood and onchocerciasis rapid test detection, respectively. Areas with sporadic, hypoendemic, and hyperendemic onchocerciasis endemicity were found. Participants with microfilaremia were considered microfilaremic, and those without microfilaremia were seen as amicrofilaremic. Of the 471 study participants, 40.5% (n = 191) had microfilariae. Among them, Mansonella spp. was the most common (78.2%, n = 147), followed by Loa loa (41.4%, n = 79). The association between the two species represented 18.3% (n = 35). The specific immunoglobulins of Onchocerca volvulus were detected in 24.2% of participants (n = 87/359). Overall prevalence of L. loa was 16.8%. Hypermicrofilaremia was found in 3% (N = 14), and one participant had more than 30,000 microfilaremiae per milliliter. The frequency of L. loa did not vary according to the level of onchocerciasis transmission. Pruritus was the most common clinical sign (60.5%, n = 285) reported, mainly in microfilaremic participants (72.2%, n = 138/191). The prevalence of L. loa microfilaria in the study population was below the threshold at risk for the occurrence of serious side effects due to ivermectin. Clinical manifestations frequently observed could be exacerbated by microfilaremia in areas where onchocerciasis transmission is high.
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Affiliation(s)
- Reinne Moutongo Mouandza
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Jean Romain Mourou
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Bridy Moutombi Ditombi
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Hadry Roger Sibi Matotou
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Bernadette Ekomi
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Marielle Karine Bouyou-Akotet
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
| | - Denise Patricia Mawili-Mboumba
- Department of Parasitology-Mycology and Tropical Medicine, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon
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17
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Hedtke SM, Kode A, Ukety TO, Mande JL, Abhafule GM, Raciu AA, Uvon CB, Jada SR, Hotterbeekx A, Siewe Fodjo JN, Mitreva M, Sebit W, Colebunders R, Grant WN, Kuesel AC. Procedure for Handling and Storage of Onchocerca volvulus Microfilariae Obtained from Skin Snips for Downstream Genetic Work. Trop Med Infect Dis 2023; 8:445. [PMID: 37755906 PMCID: PMC10536066 DOI: 10.3390/tropicalmed8090445] [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: 08/13/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
WHO and endemic countries target elimination of transmission of Onchocerca volvulus, the parasite causing onchocerciasis. Population genetic analysis of O. volvulus may provide data to improve the evidence base for decisions on when, where, and for how long to deploy which interventions and post-intervention surveillance to achieve elimination. Development of necessary methods and tools requires parasites suitable for genetic analysis. Based on our experience with microfilariae obtained from different collaborators, we developed a microfilariae transfer procedure for large-scale studies in the Democratic Republic of Congo (DRC) comparing safety and efficacy of ivermectin, the mainstay of current onchocerciasis elimination strategies, and moxidectin, a new drug. This procedure is designed to increase the percentage of microfilariae in skin snips suitable for genetic analysis, improve assignment to metadata, and minimize time and materials needed by the researchers collecting the microfilariae. Among 664 microfilariae from South Sudan, 35.7% and 39.5% failed the mitochondrial and nuclear qPCR assay. Among the 576 microfilariae from DRC, 16.0% and 16.7% failed these assays, respectively. This difference may not only be related to the microfilariae transfer procedure but also to other factors, notably the ethanol concentration in the tubes in which microfilariae were stored (64% vs. ≥75%).
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Affiliation(s)
- Shannon M. Hedtke
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (W.N.G.)
| | - Anusha Kode
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (W.N.G.)
| | - Tony O. Ukety
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo; (T.O.U.); (J.L.M.); (G.M.A.); (A.A.R.); (C.B.U.)
| | - Jöel L. Mande
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo; (T.O.U.); (J.L.M.); (G.M.A.); (A.A.R.); (C.B.U.)
| | - Germain M. Abhafule
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo; (T.O.U.); (J.L.M.); (G.M.A.); (A.A.R.); (C.B.U.)
| | - Anuarite A. Raciu
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo; (T.O.U.); (J.L.M.); (G.M.A.); (A.A.R.); (C.B.U.)
| | - Claude B. Uvon
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo; (T.O.U.); (J.L.M.); (G.M.A.); (A.A.R.); (C.B.U.)
| | | | - An Hotterbeekx
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | | | - Makedonka Mitreva
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA;
| | - Wilson Sebit
- National Public Health Laboratory, Juba P.O. Box 88, South Sudan;
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Warwick N. Grant
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (W.N.G.)
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, CH-1211 Geneva, Switzerland;
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18
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Hedtke SM, Choi YJ, Kode A, Chalasani GC, Sirwani N, Jada SR, Hotterbeekx A, Mandro M, Siewe Fodjo JN, Amambo GN, Abong RA, Wanji S, Kuesel AC, Colebunders R, Mitreva M, Grant WN. Assessing Onchocerca volvulus Intensity of Infection and Genetic Diversity Using Mitochondrial Genome Sequencing of Single Microfilariae Obtained before and after Ivermectin Treatment. Pathogens 2023; 12:971. [PMID: 37513818 PMCID: PMC10385737 DOI: 10.3390/pathogens12070971] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/16/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Onchocerciasis is a neglected tropical disease targeted for elimination using ivermectin mass administration. Ivermectin kills the microfilariae and temporarily arrests microfilariae production by the macrofilariae. We genotyped 436 microfilariae from 10 people each in Ituri, Democratic Republic of the Congo (DRC), and Maridi County, South Sudan, collected before and 4-5 months after ivermectin treatment. Population genetic analyses identified 52 and 103 mitochondrial DNA haplotypes among the microfilariae from DRC and South Sudan, respectively, with few haplotypes shared between people. The percentage of genotype-based correct assignment to person within DRC was ~88% and within South Sudan ~64%. Rarefaction and extrapolation analysis showed that the genetic diversity in DRC, and even more so in South Sudan, was captured incompletely. The results indicate that the per-person adult worm burden is likely higher in South Sudan than DRC. Analyses of haplotype data from a subsample (n = 4) did not discriminate genetically between pre- and post-treatment microfilariae, confirming that post-treatment microfilariae are not the result of new infections. With appropriate sampling, mitochondrial haplotype analysis could help monitor changes in the number of macrofilariae in a population as a result of treatment, identify cases of potential treatment failure, and detect new infections as an indicator of continuing transmission.
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Affiliation(s)
- Shannon M. Hedtke
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Young-Jun Choi
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA; (Y.-J.C.); (M.M.)
| | - Anusha Kode
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Gowtam C. Chalasani
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | - Neha Sirwani
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
| | | | - An Hotterbeekx
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Michel Mandro
- Provincial Health Division Ituri, Ministry of Health, Bunia P.O. Box 57, Democratic Republic of the Congo;
| | - Joseph N. Siewe Fodjo
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Glory Ngongeh Amambo
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
| | - Raphael A. Abong
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
- Research Foundation for Tropical Diseases and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Samuel Wanji
- Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (G.N.A.); (R.A.A.); (S.W.)
- Research Foundation for Tropical Diseases and Environment (REFOTDE), Buea P.O. Box 474, Cameroon
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1202 Geneva, Switzerland;
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.H.); (J.N.S.F.); (R.C.)
| | - Makedonka Mitreva
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA; (Y.-J.C.); (M.M.)
| | - Warwick N. Grant
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia; (A.K.); (G.C.C.); (N.S.); (W.N.G.)
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19
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Boakye D, Mackenzie C, Tallant J, Heggen A, Leff S, Nadjilar L, Sow M. Enhancing onchocerciasis elimination program management: A biological approach to deciding when to begin Stop Mass Drug Administration activities. PLoS Negl Trop Dis 2023; 17:e0011348. [PMID: 37440479 DOI: 10.1371/journal.pntd.0011348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/15/2023] Open
Abstract
Understanding when it is the appropriate time to stop administering the drugs in a chemotherapy-centered treatment program such as onchocerciasis remains a challenge due to cost, imperfect testing procedures, and a lack of long-term experience. Different approaches for assessing when a program can begin the extensive stop-treatment surveys have been recommended, and tested, with varying results. We describe here a practical approach that is based on information on both transmission as well as infection. This new protocol first defines operational transmission zones (OTZs) based on vector breeding sites followed by an epidemiological assessment of the resident populations adjacent to these breeding sites. Basing decisions to stop MDA treatment based on breeding site locations (i.e., transmission zones) rather than on political administrative units, is a practical, cost-effective approach. Importantly, this biology-based approach is more closely related to the actual state of onchocerciasis transmission.
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Affiliation(s)
- Daniel Boakye
- Reaching the Last Mile Fund, The END Fund, New York, New York, United States of America
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Charles Mackenzie
- Reaching the Last Mile Fund, The END Fund, New York, New York, United States of America
- NTD Support Center, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Jamie Tallant
- Reaching the Last Mile Fund, The END Fund, New York, New York, United States of America
| | - Anne Heggen
- Reaching the Last Mile Fund, The END Fund, New York, New York, United States of America
| | - Sashi Leff
- Reaching the Last Mile Fund, The END Fund, New York, New York, United States of America
| | - Lokemla Nadjilar
- Onchocerciasis Elimination Program, Ministry of Health, Republic of Tchad
| | - Moussa Sow
- Onchocerciasis Elimination Program, Ministry of Health, Republic of Mali
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Chikezie FM, Opara KN, Ubulom PME, Yaro CA, Al-Akeel RK, Osei-Atweneboana MY, Alexiou A, Papadakis M, Batiha GES. Onchocerciasis transmission status in some endemic communities of Cross River State, Nigeria after two decades of mass drug administration with ivermectin. Sci Rep 2023; 13:5413. [PMID: 37012274 PMCID: PMC10070439 DOI: 10.1038/s41598-023-31446-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/11/2023] [Indexed: 04/05/2023] Open
Abstract
Onchocerciasis is a parasitic disease transmitted by black flies. Human onchocerciasis is a public health and socioeconomic problem in Nigeria. Its prevalence and morbidity have reduced over the years because of control efforts especially, Mass Drug Administration with ivermectin. The current goal is to eliminate the disease transmission by 2030. Understanding the changes in transmission patterns in Cross River State is critical to elimination of onchocerciasis in Nigeria. This study was designed to determine the transmission dynamics of onchocerciasis in Cross River State after over two decades of mass ivermectin distribution in endemic communities. Agbokim, Aningeje, Ekong Anaku and Orimekpang are four endemic communities from three Local Government Areas of the State selected for this study. Transmission indices such as infectivity rates, biting rates and transmission potentials, parity rates and diurnal biting activities were determined. A total of 15,520 adult female flies were caught on human baits, Agbokim (2831), Aningeje (6209), Ekong Anaku (4364) and Orimekpang (2116). A total of 9488 and 5695 flies were collected during the rainy and dry seasons respectively in the four communities studied. The differences in relative abundance among the communities were statistically significant (P < 0.001). Monthly and seasonal fly numbers varied significantly (P < 0.008). There were differences in diurnal biting activities of flies in this study at different hours of the day and different months. The peak monthly biting rates were 5993 (Agbokim, October), 13,134 (Aningeje, October), 8680 (Ekong Anaku, October) and 6120 (Orimekpang, September) bites/person/month while the lowest monthly biting rates were 400 (Agbokim, November), 2862 (Aningeje, August), 1405 (Ekong Anaku, January) and 0.0 (Orimekpang, November and December) bites/person/month. Differences in biting rates among the study communities were significant (P < 0.001). The peak monthly transmission potential in Aningeje was 160 infective bites/person/month in the month of February while the lowest (except for months with no transmission) was 42 infective bites/person/month in the month of April. All other study sites had no ongoing transmission in this study. Transmission studies showed that there is progress toward transmission interruption especially in 3 out of the four studied areas. Molecular O-150 poolscreen studies is required to confirm the true transmission situation in the areas.
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Affiliation(s)
- Friday Maduka Chikezie
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Kenneth Nnamdi Opara
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Peace Mayen Edwin Ubulom
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Clement Ameh Yaro
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Rasha Khalifah Al-Akeel
- Department of Zoology, Faculty of Entomology and Parasitology, King Saud University, Riyadh, Saudi Arabia
| | | | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, 1030, Wien, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, Heusnerstrasse 40, University of Witten-Herdecke, 42283, Wuppertal, Germany.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt
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Wangwiwatsin A, Kulwong S, Phetcharaburanin J, Namwat N, Klanrit P, Loilome W, Maleewong W, Reid AJ. Toward novel treatment against filariasis: Insight into genome-wide co-evolutionary analysis of filarial nematodes and Wolbachia. Front Microbiol 2023; 14:1052352. [PMID: 37032902 PMCID: PMC10073474 DOI: 10.3389/fmicb.2023.1052352] [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: 09/26/2022] [Accepted: 02/16/2023] [Indexed: 04/11/2023] Open
Abstract
Infectious diseases caused by filarial nematodes are major health problems for humans and animals globally. Current treatment using anti-helminthic drugs requires a long treatment period and is only effective against the microfilarial stage. Most species of filarial nematodes harbor a specific strain of Wolbachia bacteria, which are essential for the survival, development, and reproduction of the nematodes. This parasite-bacteria obligate symbiosis offers a new angle for the cure of filariasis. In this study, we utilized publicly available genome data and putative protein sequences from seven filarial nematode species and their symbiotic Wolbachia to screen for protein-protein interactions that could be a novel target against multiple filarial nematode species. Genome-wide in silico screening was performed to predict molecular interactions based on co-evolutionary signals. We identified over 8,000 pairs of gene families that show evidence of co-evolution based on high correlation score and low false discovery rate (FDR) between gene families and obtained a candidate list that may be keys in filarial nematode-Wolbachia interactions. Functional analysis was conducted on these top-scoring pairs, revealing biological processes related to various signaling processes, adult lifespan, developmental control, lipid and nucleotide metabolism, and RNA modification. Furthermore, network analysis of the top-scoring genes with multiple co-evolving pairs suggests candidate genes in both Wolbachia and the nematode that may play crucial roles at the center of multi-gene networks. A number of the top-scoring genes matched well to known drug targets, suggesting a promising drug-repurposing strategy that could be applicable against multiple filarial nematode species.
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Affiliation(s)
- Arporn Wangwiwatsin
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Siriyakorn Kulwong
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Jutarop Phetcharaburanin
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Nisana Namwat
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Poramate Klanrit
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Watcharin Loilome
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Khon Kaen University Phenome Centre, Khon Kaen University, Khon Kaen, Thailand
| | - Wanchai Maleewong
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Adam J Reid
- Parasite Genomics Group, Wellcome Sanger Institute, Hinxton, United Kingdom
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
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Boullé C, Chesnais CB, Kamgno J, Gardon J, Chippaux JP, Ranque S, Garcia A, Pion SD, Boussinesq M. Evaluating post-treatment Loa loa microfilarial densities to classify serious adverse events caused by ivermectin: a retrospective analysis. THE LANCET. MICROBE 2023; 4:e93-e101. [PMID: 36646105 DOI: 10.1016/s2666-5247(22)00331-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/12/2022] [Accepted: 11/07/2022] [Indexed: 01/15/2023]
Abstract
BACKGROUND The elimination of onchocerciasis requires increasing ivermectin treatment coverage in communities hypoendemic for onchocerciasis. In areas where loiasis is co-endemic, this approach is complicated by the risk of serious adverse events following treatment with ivermectin in individuals with a high Loa loa microfilarial density (MFD). We aimed to evaluate the extent to which the pre-treatment MFD can be inferred from post-treatment MFDs. METHODS For this retrospective analysis, we used data from seven clinical or community trials (six were used for the main analysis and one for the secondary analysis) conducted in Cameroon, in which MFDs were measured both before and after (within 14 days) receiving a single dose of ivermectin (150-200 μg/kg bodyweight). The primary objective was to establish the receiver operating characteristic curves and the corresponding area under the curve statistics of MFD measured after treatment to classify pre-treatment MFD (MFDD0) according to common risk thresholds of serious adverse events. We assessed the performance of post-treatment MFD to accurately classify MFDD0 according to commonly used thresholds using bootstrap procedures. FINDINGS 281 individuals with MFD measurements available before and 3-10 days after ivermectin treatment were enrolled. Our results show that an MFD of more than 3500 L loa microfilariae per mL of blood (mf per mL) 3 or 4 days after treatment indicates a 68·6% chance (positive predictive value) of an MFDD0 of more than 20 000 mf per mL. An MFD of more than 3500 mf per mL at day 5-10 corresponds to a 72·2% chance of having an MFDD0 of more than 20 000 mf per mL. Conversely, an MFD of less than 2500 microfilariae per mL at day 3-4 or day 5-10 corresponds to a probability of 92·3% or 92·8% (negative predictive value) of having MFDD0 of less than 20 000 mf per mL. An MFD less than 1500 mf per mL on days 3-4 after treatment was associated with a 78·3% probability of having an MFDD0 less than 8000 mf per mL; this probability increased to 89·6% on days 5-10 after treatment. INTERPRETATION The MFD threshold of 1000 mf per mL within 1 month of treatment, which is commonly used to attribute the occurrence of a serious adverse event to ivermectin, should be revised. In this study, we present tables that can help to assess this attributability as part of mass or individual treatments. FUNDING None.
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Affiliation(s)
- Charlotte Boullé
- UMI 233, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Université de Montpellier, Montpellier, France; Services des Maladies Infectieuses et Tropicales, Montpellier University Hospital, Centre Hospitalier Universitaire La Colombière, Montpellier, France.
| | - Cédric B Chesnais
- UMI 233, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Université de Montpellier, Montpellier, France
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon; Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Jacques Gardon
- Hydrosciences Montpellier, IRD, Université de Montpellier, Centre National de la Recherche Scientifique, Montpellier, France
| | | | - Stéphane Ranque
- Aix Marseille University, IRD, Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de Santé des Armées (SSA), VITROME, Institut Hospito-Universitaire (IHU)-Méditerranée Infection, Marseille, France
| | - André Garcia
- UMR 261 MERIT, IRD, Paris University, Paris, France
| | - Sébastien D Pion
- UMI 233, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Université de Montpellier, Montpellier, France
| | - Michel Boussinesq
- UMI 233, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Université de Montpellier, Montpellier, France.
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Evaluating the impact of alternative intervention strategies in accelerating onchocerciasis elimination in an area of persistent transmission in the West Region of Cameroon. PLoS Negl Trop Dis 2022; 16:e0010591. [PMID: 36542603 PMCID: PMC9770396 DOI: 10.1371/journal.pntd.0010591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/17/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Alternative strategies are recommended to accelerate onchocerciasis elimination in problematic areas including areas where annual ivermectin (IVM) distributions are unable to interrupt transmission. The aim of this study was to accelerate progress towards elimination in the Massangam health district, West Region of Cameroon where impact evaluations demonstrated ongoing transmission of onchocerciasis infection and high microfilaria (mf) prevalence despite more than 20 years of annual IVM distribution. METHODOLOGY/PRINCIPAL FINDINGS Parasitological, entomological, and breeding site surveys were conducted in 2015 delineating a focus of high transmission and identified three communities with high mf prevalence. Individuals in these communities were screened for mf yearly for a period of two years and those positive treated each year with doxycycline 100mg daily for five weeks. In addition, surrounding communities were given biannual IVM. Temephos-based applications were performed once a week for 10 consecutive weeks on Simulium damnosum s.l. breeding sites. Parasitological and entomological assessments were conducted after two years of implementation and findings compared with 2015 baseline. Alternative strategies accelerated progress towards elimination through a significant mf reduction (χ2: 40.1; p<0.001) from 35.7% (95%CI: 29.0-42.8) to 12.3% (95%CI, 9.0-16.4). Reductions were furthermore recorded over a longer period, with a reduction of prevalence of 29.0% under AIS in 2017-2019 compared to 14.6% with IVM in 2011-2015; and by 23.2% following the two years of alternative strategies compared to 20.3% reduction over 15 years of treatment with IVM (1996-2011). Entomological assessment demonstrates that transmission is still ongoing despite the reduction in mf which is expected in an environment with complex breeding sites and open transmission zones, i.e., where migration of flies or humans to and from neighbouring areas is common. CONCLUSION/SIGNIFICANCE This study provides evidence that alternative strategies are feasible and effective and should be considered in areas where transmission is sustained throughout long term uninterrupted MDA with IVM. However, there is need to consider wider transmission zones, and further explore optimal timing of larviciding with treatment to impact transmission.
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24
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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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25
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Domche A, Nwane PB, Nana Djeunga HC, Njitchouang GR, Pion SD, Boussinesq M, Njiokou F, Kamgno J. Status of Onchocerca volvulus (Spirurida: Onchocercidae) Transmission and Effect of Climatic Variables on the Vector Population Dynamics After Two Decades of Ivermectin-based Preventive Chemotherapy in the Mbam Valley (Centre Region, Cameroon). JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:2130-2138. [PMID: 36111691 DOI: 10.1093/jme/tjac133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Entomological indicators of onchocerciasis transmission and the effect of climatic variables on the vector population dynamics were investigated in two first-line villages after more than two decades of mass drug administration with ivermectin. Female blackflies were collected in two villages (Bayomen and Biatsota) using human landing method for a period of 12 months. Blackflies were dissected and entomological indices were computed. Monthly temperature, precipitation, and humidity were collected and the Spearman correlation rank test was used to assess the relationship between biting rates and climatic variables. The highest biting rates (62,280 bites/human/month in Bayomen and 42,090 bites/human/month in Biatsota) were recorded during the long rainy season (November). The Onchocerca volvulus transmission was greater during the long dry season in both villages, with a peak at the beginning of the long dry season in Biatsota (100 infective larvae/human/month), and at the middle of the long dry season in Bayomen (92 infective larvae/human/month). No correlation was found between biting rates and selected climatic variables in the two villages. This study revealed that onchocerciasis transmission is ongoing in the study area despite almost 25 years of Community-Directed Treatment with Ivermectin. In accordance with WHO recommendations, vector control should be used in combination with mass drug administration to accelerate transmission interruption of onchocerciasis. To be optimal, this vector control should be implemented during the long dry season (November to March) when water volumes are low and transmission potentials are high.
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Affiliation(s)
- André Domche
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Philippe B Nwane
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Hugues C Nana Djeunga
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Guy R Njitchouang
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Sébastien D Pion
- TransVIHMI, University of Montpellier, Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
| | - Michel Boussinesq
- TransVIHMI, University of Montpellier, Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Joseph Kamgno
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
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Ekpo UF, Eneanya OA, Nwankwo EN, Soneye IY, Weil GJ, Fischer PU, Nwaorgu OC. Persistence of onchocerciasis in villages in Enugu and Ogun states in Nigeria following many rounds of mass distribution of ivermectin. BMC Infect Dis 2022; 22:832. [PMID: 36357828 PMCID: PMC9650792 DOI: 10.1186/s12879-022-07811-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 10/27/2022] [Indexed: 11/11/2022] Open
Abstract
Background Onchocerciasis is endemic in most local government areas (LGAs) in Enugu and Ogun states. Most meso- and hyper-endemic LGAs have received many rounds of ivermectin mass drug administration (MDA). This study aimed to determine the current prevalence of onchocerciasis in villages in Enugu and Ogun states that were formerly highly endemic and to assess progress toward elimination of the infection in areas believed to be at high risk for persistence. Methods Cross-sectional community surveys were conducted 8 to 12 months after the last round of MDA in 16 villages (6 in Enugu state and 10 in Ogun state) in individuals aged ≥ 18 years. Study participants were examined for the presence of palpable subcutaneous nodules. Skin snips from the posterior iliac crests were used to assess microfiladermia (Mf) prevalence and density. Results 643 subjects were palpated for nodules and 627 individuals (225 in Enugu state; 402 in Ogun state) provided skin snips. Nodule prevalence in the study villages ranged from 42 to 66.7% in Enugu state and from 0 to 25.0% in Ogun state. Mf prevalence in the Enugu and Ogun study villages ranged from 32 to 51.1% and 0 to 28.6%, respectively. Geometric mean skin Mf density in surveyed Enugu state villages ranged between 1 and 3.1 Mf/mg; these values were < 1 Mf/mg in all but one community in Ogun state villages. Conclusion Results from this study show that onchocerciasis persists in adults in many villages in Enugu and Ogun states despite many prior rounds of ivermectin MDA. Prevalence was higher in villages surveyed in Enugu than in Ogun. Low Mf densities suggest the MDA program is working well to reduce disease, but more time will be required to reach the elimination goal. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07811-7.
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Efon-Ekangouo A, Nana-Djeunga HC, Nwane P, Lisongue-Tonga E, Domche A, Sumo L, Osei-Atweneboana MY, Geiger A, Kamgno J. Prevalence of epilepsy in Ndom Health District (Littoral Region, Cameroon) after long-term ivermectin-based preventive chemotherapy for the control of onchocerciasis. Epilepsy Behav 2022; 136:108939. [PMID: 36252289 DOI: 10.1016/j.yebeh.2022.108939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 09/27/2022] [Accepted: 09/27/2022] [Indexed: 12/14/2022]
Abstract
Assuming the causality relationship between Onchocerca volvulus infection and epilepsy onset, preventive chemotherapy for the control onchocerciasis can result to a significant impact on epilepsy burden. This study aimed at assessing the prevalence of epilepsy in an onchocerciasis endemic area under annual CDTI for 16 years. A cross-sectional survey was conducted in two communities (Kelleng and Nkonkwalla) located in the Ndom Health District (Littoral Region, Cameroon) to assess the prevalence of epilepsy using a standardized questionnaire for non-specialists in tropical areas. Data on the nuisance of onchocerciasis vector and distance of surveyed households to the river were also collected. Epilepsy status was collected from 367 participants (sex ratio (M/F): 1.13). The crude prevalence of epilepsy was estimated at 8.4 % (95 % CI: 5.8-11.8); the highest prevalence was found in females (13.8 %; 95 % CI: 8.8-20.3) compared to males (5.0 %; 95 % CI: 2.4-9.04)) (p-value = 0.02) and in Nkonkwalla (9.0 %; 95 % CI: 5.5-13.6) (p-value = 0.82) compared to Kelleng (7.7 %; 95 % CI: 4.06-13.13). After 16 years of CDTI in Kelleng, crude prevalence of epilepsy decreased from 10.2 % to 7.2 % (p-value = 0.19), whereas the age sex-standardized prevalence dropped from 13.5 % to 7.7 % between 2004 and 2020 (p-value = 0.05). The median age of epilepsy cases shifted from 24 (IQR: 20-30) in 2004 to 28 years (IQR: 23-34) in 2020. The shift in age-specific prevalence over the years suggests a decreasing incidence of epilepsy in areas under long-term CDTI and a significant impact of onchocerciasis control on the prevalence of epilepsy.
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Affiliation(s)
- Arnauld Efon-Ekangouo
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon; INTERTRYP, Institut de Recherche pour le Développement (IRD), University of Montpellier, TA A-17/G Campus International de Baillarguet, 34398 Montpellier cedex 5, France
| | - Hugues C Nana-Djeunga
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon.
| | - Philippe Nwane
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon; Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon
| | - Elvis Lisongue-Tonga
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon
| | - André Domche
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon; Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon
| | - Laurentine Sumo
- Department of Biological Sciences, Faculty of Science, University of Bamenda, PO Box 39, Bambili, Cameroon
| | - Mike Yaw Osei-Atweneboana
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research (CSIR), Ghana; CSIR-College of Science and Technology, Accra, Ghana
| | - Anne Geiger
- INTERTRYP, Institut de Recherche pour le Développement (IRD), University of Montpellier, TA A-17/G Campus International de Baillarguet, 34398 Montpellier cedex 5, France
| | - Joseph Kamgno
- Centre for Research on Filariasis and Other Tropical Diseases (CRFilMT), PO Box 5797, Yaoundé, Cameroon; Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, PO Box 1364, Yaoundé, Cameroon
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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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Biamonte MA, Cantey PT, Coulibaly YI, Gass KM, Hamill LC, Hanna C, Lammie PJ, Kamgno J, Nutman TB, Oguttu DW, Sankara DP, Stolk WA, Unnasch TR. Onchocerciasis: Target product profiles of in vitro diagnostics to support onchocerciasis elimination mapping and mass drug administration stopping decisions. PLoS Negl Trop Dis 2022; 16:e0010682. [PMID: 35921329 PMCID: PMC9377578 DOI: 10.1371/journal.pntd.0010682] [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: 01/24/2022] [Revised: 08/15/2022] [Accepted: 07/20/2022] [Indexed: 11/19/2022] Open
Abstract
In June 2021, the World Health Organization (WHO), recognizing the need for new diagnostics to support the control and elimination of onchocerciasis, published the target product profiles (TPPs) of new tests that would support the two most immediate needs: (a) mapping onchocerciasis in areas of low prevalence and (b) deciding when to stop mass drug administration programs. In both instances, the test should ideally detect an antigen specific for live, adult O. volvulus female worms. The preferred format is a field-deployable rapid test. For mapping, the test needs to be ≥ 60% sensitive and ≥ 99.8% specific, while to support stopping decisions, the test must be ≥ 89% sensitive and ≥ 99.8% specific. The requirement for extremely high specificity is dictated by the need to detect with sufficient statistical confidence the low seroprevalence threshold set by WHO. Surveys designed to detect a 1–2% prevalence of a given biomarker, as is the case here, cannot tolerate more than 0.2% of false-positives. Otherwise, the background noise would drown out the signal. It is recognized that reaching and demonstrating such a stringent specificity criterion will be challenging, but test developers can expect to be assisted by national governments and implementing partners for adequately powered field validation. River blindness, also known as onchocerciasis, affects 21 million people, predominantly in sub-Saharan Africa. For decades, the international community has fought this disease through mass drug administration (MDA) programs focused on controlling morbidity in areas of high prevalence. Now, as part of their 2021–2030 Roadmap for Neglected Tropical Diseases, the World Health Organization (WHO) has set an ambitious goal, shifting from controlling to eliminating onchocerciasis. This implies addressing areas of low infection prevalence. As a result, new diagnostics tools are required to identify and map areas of low onchocerciasis prevalence and to help decide where to initiate MDA. Similarly, new diagnostics are required to decide when the prevalence of onchocerciasis is sufficiently low to justify stopping MDA. A WHO-appointed independent panel, the Diagnostics Technical Advisory Group for Neglected Tropical Diseases, and its subgroup specific to onchocerciasis, have established the desired Target Product Profiles (TPPs) for such new tests. The TPPs were posted in June 2021 on the WHO website. This article describes the methodology used to produce the TPPs, with an emphasis on calculating the required sensitivity and specificity characteristics.
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Affiliation(s)
- Marco A. Biamonte
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
- * E-mail:
| | - Paul T. Cantey
- Division of Parasitic Diseases and Malaria, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Yaya I. Coulibaly
- Mali International Center for Excellence in Research, Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali, Dermatology Hospital of Bamako, Bamako, Mali
| | - Katherine M. Gass
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, Georgia, United States of America
| | | | - Christopher Hanna
- Global Project Partners, Oakland, California, United States of America
| | - Patrick J. Lammie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - David W. Oguttu
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Dieudonné P. Sankara
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Wilma A. Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Thomas R. Unnasch
- Global Health Infectious Disease Research Program, University of South Florida, Tampa, Florida, United States of America
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Gebrezgabiher G, Yewhalaw D, Hailu A, Mekonnen Z. Evaluation of mass treatment with ivermectin program reach and survey coverage for onchocerciasis elimination in selected endemic areas of Ethiopia. PLoS One 2022; 17:e0271518. [PMID: 35901026 PMCID: PMC9333289 DOI: 10.1371/journal.pone.0271518] [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: 08/09/2021] [Accepted: 07/02/2022] [Indexed: 11/25/2022] Open
Abstract
Currently, national governments of onchocerciasis endemic African countries are working towards the elimination of the disease using mass drug administration (MDA) with ivermectin as a primary strategy. Attainment of this goal requires implementation of prolonged high MDA coverage in all endemic areas, and vigilant monitoring and evaluation of the program. This study was thus conducted with the purpose of i) providing estimate of ivermectin coverage, ii) validating the MDA coverage reported through community drug distributors (CDDs), iii) determining the factors associated with MDA coverage, and iv) estimating the difference between MDA program reach and survey coverage rates following MDA campaign carried out in May 2017 in Asosa and Yeki districts in Ethiopia. A community-based cross-sectional study was conducted among 2,824 study participants in Asosa and Yeki districts. A total of 50 kebeles (smallest administrative units) were randomly selected from the two districts. A systematic sampling was employed to select study households from the 50 kebeles. Then, a household member was randomly selected for the interview. Univariate and multivariate logistic regression analysis were used to determine the odds ratio and to observe the associations between the MDA survey coverage and the variables used. Eighty-seven percent (2458/2824) of the respondents from both districts responded that they were offered ivermectin during the May 2017 MDA campaign. At the district level, 1182 individuals from Yeki and 1276 from Asosa, received the drug, that indicate 88.5% and 85.8% MDA program reach in Yeki and Assosa districts, respectively. Whereas, a total of 366 individuals were not offered ivermectin in both study districts. Of these, 47(12.8%), 143(39.1%), and 176(48.1%) did not receive the drug because of program implementation-related reasons, ineligibility criteria, and personal issues, respectively. Of the 1488 and 1336 respondents in Asosa and Yeki, 1272 and 1182 participants took the drug, resulting in survey coverage rate of 85.5% (95% CI: 83.6–87.2%) and 88.5% (95% CI: 86.7–90.1%), respectively. Multivariable logistic regression analysis revealed significantly low survey coverage rate in females (AOR = 0.5, 95%CI: 0.3–0.6; p<0.001) and in those whose age ranges between 15–24 years (AOR = 0.5, 95%CI: 0.3–0.8; p = 0.007) and 25–34 years (AOR = 0.5, 95%CI: 0.3–0.9; p = 0.021) in Asosa. The researchers believe that the current study generated operational evidence on MDA program reach and coverage rates in two study districts in Ethiopia. The survey coverages were lower than the recommended 90% minimum threshold for success. Only Yeki district reached the 90% threshold survey coverage. Both districts had reported higher coverages than the survey estimates (even outside the 95% CI), thus, were not validated. The majority (60.9%) of the reasons for not receiving the drug were related to program implementation and recipients`personal issues. Efforts must therefore be directed to enhance MDA coverage in future rounds via proper MDA planning and implementation, such as allocating adequate time to the MDA activities, health education, and mobilizing of all segments of the population, including adolescents and the youth. The researchers also recommend such studies to be extended to other MDA programs for other neglected tropical diseases (NTDs).
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Affiliation(s)
- Gebremedhin Gebrezgabiher
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- College of Veterinary Medicine, Samara University, Samara, Ethiopia
- * E-mail:
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Zeleke Mekonnen
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
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Dedhiya R, Kakileti ST, Deepu G, Gopinath K, Opoku N, King C, Manjunath G. Evaluation of Non-Invasive Thermal Imaging for Detection of Viability of Onchocerciasis Worms. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:3518-3521. [PMID: 36086671 DOI: 10.1109/embc48229.2022.9871140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Onchocerciasis is causing blindness in over half a million people in the world today. Drug development for the disease is crippled as there is no way of measuring effectiveness of the drug without an invasive procedure. Drug efficacy measurement through assessment of viability of onchocerca worms requires the patients to undergo nodulectomy which is invasive, expensive, time-consuming, skill-dependent, infrastructure dependent and lengthy process. In this paper, we discuss the first-ever study that proposes use of machine learning over thermal imaging to non-invasively and accurately predict the viability of worms. The key contributions of the paper are (i) a unique thermal imaging protocol along with pre-processing steps such as alignment, registration and segmentation to extract interpretable features (ii) extraction of relevant semantic features (iii) development of accurate classifiers for detecting the existence of viable worms in a nodule. When tested on a prospective test data of 30 participants with 48 palpable nodules, we achieved an Area Under the Curve (AUC) of 0.85. Clinical Relevance- This is the first ever research effort of using thermal imaging in the assessment of viability of onchocerca worms and it resulted in a very high specificity>95% which makes it a promising modality to pursue further.
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Ekanya R, Obie ED, Hamill L, Thorogood S, Abong RA, Njouendou AJ, Amuam A, Ndzeshang BL, Nkimbeng DA, Cho JF, Esum ME, Enyong P, Turner JD, Taylor MJ, Wanji S. The preparatory phase for ground larviciding implementation for chocerciasis control in the Meme River Basin in South West Cameroon: the COUNTDOWN Consortium alternative strategy implementation trial. Parasit Vectors 2022; 15:219. [PMID: 35729597 PMCID: PMC9210632 DOI: 10.1186/s13071-022-05300-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Onchocerciasis control using ivermectin alone has been achieved in some endemic savannah zones of Africa. In the forest regions, the co-endemicity with Loa loa has led to severe adverse events (SAEs) resulting in poor adherence of community members to ivermectin mass drug administration (MDA). This may jeopardize achieving the interruption of transmission of onchocerciasis. Therefore, to accelerate the elimination of onchocerciasis in L. loa co-endemic zones, alternative treatment strategies (ATS) including ground larviciding may be necessary. This study aimed at identifying Simulium breeding sites, cytospecies, transmission profile, susceptibility of Simulium larvae to insecticide (temephos) and identification of some non-target aquatic fauna prior to the implementation of the COUNTDOWN consortium ground larviciding alternative strategy in the Meme River Basin in South West Cameroon. METHODS A topographic map and entomological survey were used to determine breeding sites. Larvae and adults were identified using standard identification keys. Susceptibility tests were carried out on collected larvae by exposing them to decreasing concentrations of temephos and assessing survival rates while the cytospecies were identified using cytotaxonomy. Various entomological indicators were assessed from dissected flies. Fishing was used as proxy to traps to assess some aquatic fauna at different sites. RESULTS Twenty-two breeding sites were prospected in the Meme River Basin with eight productive for larvae. A concentration of 0.5-0.1 mg/l temephos induced 100% larval mortality. As the concentration of temephos decreased from 0.05 to 0.0025 mg/l, mortality of larvae also decreased from 98.7 to 12%. Nine cytospecies were observed in the Meme River Basin; 13,633 flies were collected and 4033 dissected. A total of 1455 flies were parous (36.1%), 224 flies were infected (5.5%), and 64 were infective (1.6%). Aquatic fauna observed included Cyprinus spp., Clarias spp., crabs, tadpoles, beetles and larvae of damsel fly. CONCLUSIONS Onchocerciasis is being actively transmitted within the Meme River Basin. Simulium larvae are susceptible to temephos, and nine cytospecies are present. Non-target fauna observed included fishes, frogs, crabs and insects. Besides treatment with ivermectin, vector control through ground larviciding may be a complementary strategy to accelerate onchocerciasis elimination in the study area.
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Affiliation(s)
- Relindis Ekanya
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Elisabeth Dibando Obie
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Louise Hamill
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Sophie Thorogood
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Raphael Awah Abong
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Abdel Jelil Njouendou
- COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon.,COUNTDOWN, Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Andrew Amuam
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Bertrand Lontum Ndzeshang
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Desmond Akumtoh Nkimbeng
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Jerome Fru Cho
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Mathias Eyong Esum
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Peter Enyong
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon.,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon
| | - Joseph D Turner
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Mark J Taylor
- COUNTDOWN, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Samuel Wanji
- COUNTDOWN, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon. .,COUNTDOWN, Research Foundation for Tropical Diseases and Environment, Buea, Cameroon.
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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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Djune-Yemeli L, Domché A, Nana-Djeunga HC, Donfo-Azafack C, Lenou-Nanga CG, Masumbe-Netongo P, Kamgno J. Relationship between skin snip and Ov16 ELISA: Two diagnostic tools for onchocerciasis in a focus in Cameroon after two decades of ivermectin-based preventive chemotherapy. PLoS Negl Trop Dis 2022; 16:e0010380. [PMID: 35499993 PMCID: PMC9098087 DOI: 10.1371/journal.pntd.0010380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/12/2022] [Accepted: 03/31/2022] [Indexed: 11/28/2022] Open
Abstract
Background Onchocerciasis elimination currently relies on repeated ivermectin-based preventive chemotherapy. Current World Health Organization’s guidelines strongly recommend, though with low evidence of certainty, the use of Ov16 serology testing in children younger than 10 years old to assess whether mass drugs administration can be safely stopped. Therefore, more evidences are needed to support the use of this marker as sero-evaluation tool. This study aimed at determining the relationship between microfilaridermia and anti-Ov16 IgG4, and their variation according to age, gender and ivermectin intake history. Methodology A cross-sectional survey was conducted in an area where ivermectin-based MDA has been implemented since more than 20 years. A questionnaire was used to record ivermectin intake history for the last 5 years. All volunteers aged ≥2 years were tested for microfilaridermia. IgG4 antibodies against Ov16 antigen were determined using the Standard Diagnostic Ov16 IgG4 ELISA kits and the recombinant anti-Ov16 AbD19432 antibodies. Prevalences, microfilaridermia counts and IgG4 concentrations were compared with regards to age, gender and history of ivermectin intake. Principal findings The prevalence of skin microfilariae was 23.4% (95% CI: 23.4–30.8), whereas Ov16 seroprevalence was 53.2% (95% CI: 47.9–58.4). A moderate positive percentage agreement (50.4%) and a high negative percentage agreement (69.2%) was found between skin snip and Ov16 serology in the whole population, while in children aged <10 years, the agreements were higher (positive percentage agreement: 62.6%; negative percentage agreement: 83.5%). In addition, no associations were found between ivermectin intake, Mf counts and estimated IgG4 concentration of participants. Anti-Ov16 IgG4 were higher in individuals harboring microfilariae than their negative counterparts (p<0.0001), though a negative correlation was found between skin microfilarial counts and anti-Ov16 IgG4 levels (r = -0.2400; p = 0.03). No variation in microfilarial counts according to age and gender was observed. Though positively correlated with age (r = 0.4020; p<0.0001), IgG4 was significantly different between the different age classes (p<0.0001). Conclusion/Significance Our results revealed moderate positive and negative agreements between parasitological and immunological parameters of onchocerciasis infection after several rounds MDA. Anti-Ov16 IgG4 levels increased with age but decreased with microfilarial counts, suggesting a variation of anti-Ov16 IgG4 as a result of constant exposure and accumulation of infection. This brings evidence sustaining the use of Ov16 serology in children as evaluation tool. However, additional investigations are needed to further reshape the appropriate age range among children aged <10 years old. The elimination of onchocerciasis places high demands on monitoring and evaluation. The current WHO’s guidelines recommend the use of serological test (ELISA) to determine the presence of IgG4 antibodies to the O. volvulus specific antigen Ov16 among children aged <10 years old, thought with low evidence of certainty. In this paper, we explored the relationship between anti-Ov16 IgG4 antibodies and microfilaridermia counts, and assessed their variation according to age, gender and history of ivermectin intake. Our findings revealed no variation of Mf count and IgG4 with ivermectin intake. However, we observed that anti-Ov16 IgG4 decrease with microfilaridermia counts, but an increasing trend was observed with age. This brings evidence sustaining the use of Ov16 serology testing as exposition marker in children younger than 10 years. However, children age 2 to 4 years seem to have a very low anti-Ov16 IgG4 concentration, this finding should be considered when defining the age class for seroprevalence evaluation.
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Affiliation(s)
- Linda Djune-Yemeli
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Molecular Diagnosis Research Group, Biotechnology Centre-University of Yaoundé I (BTC-UY-I), Yaoundé, Cameroon
| | - André Domché
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Hugues C. Nana-Djeunga
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Cyrille Donfo-Azafack
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Cedric G. Lenou-Nanga
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Palmer Masumbe-Netongo
- Molecular Diagnosis Research Group, Biotechnology Centre-University of Yaoundé I (BTC-UY-I), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
- * E-mail:
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Bakajika D, Kanza EM, Opoku NO, Howard HM, Mambandu GL, Nyathirombo A, Nigo MM, Kennedy KK, Masembe SL, Mumbere M, Kataliko K, Bolay KM, Attah SK, Olipoh G, Asare S, Vaillant M, Halleux CM, Kuesel AC. Effect of a single dose of 8 mg moxidectin or 150 μg/kg ivermectin on O. volvulus skin microfilariae in a randomized trial: Differences between areas in the Democratic Republic of the Congo, Liberia and Ghana and impact of intensity of infection. PLoS Negl Trop Dis 2022; 16:e0010079. [PMID: 35476631 PMCID: PMC9084535 DOI: 10.1371/journal.pntd.0010079] [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: 12/12/2021] [Revised: 05/09/2022] [Accepted: 03/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background Our study in CDTI-naïve areas in Nord Kivu and Ituri (Democratic Republic of the Congo, DRC), Lofa County (Liberia) and Nkwanta district (Ghana) showed that a single 8 mg moxidectin dose reduced skin microfilariae density (microfilariae/mg skin, SmfD) better and for longer than a single 150μg/kg ivermectin dose. We now analysed efficacy by study area and pre-treatment SmfD (intensity of infection, IoI). Methodology/Principal findings Four and three IoI categories were defined for across-study and by-study area analyses, respectively. We used a general linear model to analyse SmfD 1, 6, 12 and 18 months post-treatment, a logistic model to determine the odds of undetectable SmfD from month 1 to month 6 (UD1-6), month 12 (UD1-12) and month 18 (UD1-18), and descriptive statistics to quantitate inter-interindividual response differences. Twelve months post-treatment, treatment differences (difference in adjusted geometric mean SmfD after moxidectin and ivermectin in percentage of the adjusted geometric mean SmfD after ivermectin treatment) were 92.9%, 90.1%, 86.8% and 84.5% in Nord Kivu, Ituri, Lofa and Nkwanta, and 74.1%, 84.2%, 90.0% and 95.4% for participants with SmfD 10–20, ≥20-<50, ≥50-<80, ≥80, respectively. Ivermectin’s efficacy was lower in Ituri and Nkwanta than Nord Kivu and Lofa (p≤0.002) and moxidectin’s efficacy lower in Nkwanta than Nord Kivu, Ituri and Lofa (p<0.006). Odds ratios for UD1-6, UD1-12 or UD1-18 after moxidectin versus ivermectin treatment exceeded 7.0. Suboptimal response (SmfD 12 months post-treatment >40% of pre-treatment SmfD) occurred in 0%, 0.3%, 1.6% and 3.9% of moxidectin and 12.1%, 23.7%, 10.8% and 28.0% of ivermectin treated participants in Nord Kivu, Ituri, Lofa and Nkwanta, respectively. Conclusions/Significance The benefit of moxidectin vs ivermectin treatment increased with pre-treatment IoI. The possibility that parasite populations in different areas have different drug susceptibility without prior ivermectin selection pressure needs to be considered and further investigated. Clinical Trial Registration Registered on 14 November 2008 in Clinicaltrials.gov (ID: NCT00790998). Onchocerciasis or river blindness is a parasitic disease primarily in sub-Saharan Africa and Yemen. It can cause debilitating morbidity including severe itching, skin changes, visual impairment and even blindness. Many years of control efforts, today primarily based on mass administration of ivermectin (MDA) in endemic communities, have reduced morbidity and the percentage of infected individuals so that elimination of parasite transmission is now planned. WHO estimated that in 2020 more than 239 million people required MDA. Ivermectin may not be sufficiently efficacious to achieve elimination everywhere. Our study in areas in Liberia, Ghana and the Democratic Republic of the Congo where MDA had not been implemented yet showed that one treatment with 8 mg moxidectin reduced parasite levels in the skin better and for longer than one treatment with 150 μg/kg ivermectin, the dose used during MDA. Here we show that people with higher numbers of parasites in the skin benefited more from moxidectin treatment than those with lower numbers and that the efficacy of ivermectin and moxidectin differed between study areas. Provided WHO and countries include moxidectin in guidelines and policies, this information could help decisions on when and where to use moxidectin.
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Affiliation(s)
- Didier Bakajika
- Centre de Recherche en Maladies Tropicale de l’Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo Democratic Republic of the Congo (DRC)
| | - Eric M. Kanza
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo (DRC)
| | | | - Hayford M. Howard
- Clinical Research Center, Liberia Institute for Biomedical Research, Bolahun, 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 Democratic Republic of the Congo (DRC)
| | - Amos Nyathirombo
- Centre de Recherche en Maladies Tropicale de l’Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo Democratic Republic of the Congo (DRC)
| | - Maurice M. Nigo
- Centre de Recherche en Maladies Tropicale de l’Ituri, Hôpital Générale de Référence de Rethy, Ituri, Democratic Republic of the Congo Democratic Republic of the Congo (DRC)
| | - Kambale Kasonia Kennedy
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo (DRC)
| | - Safari L. Masembe
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo (DRC)
| | - Mupenzi Mumbere
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo (DRC)
| | - Kambale Kataliko
- Centre de Recherche Clinique de Butembo, Université Catholique du Graben, Site Horizon, Butembo, Nord Kivu, Democratic Republic of the Congo (DRC)
| | - Kpehe M. Bolay
- Clinical Research Center, Liberia Institute for Biomedical Research, Bolahun, Liberia
| | - Simon K. Attah
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
| | - George Olipoh
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
| | - Sampson Asare
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
| | - 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
- * E-mail:
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Reducing onchocerciasis-associated morbidity in onchocerciasis-endemic foci with high ongoing transmission: a focus on the children. Int J Infect Dis 2022; 116:302-305. [PMID: 35074518 PMCID: PMC8866381 DOI: 10.1016/j.ijid.2022.01.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/22/2022] Open
Abstract
Efforts are being directed toward the elimination of onchocerciasis transmission in endemic areas with community-directed treatment with ivermectin (CDTI) in Africa, which greatly reduces onchocerciasis-associated disease. However, onchocerciasis remains a major public health problem in areas of South Sudan, the Democratic Republic of the Congo, Cameroon, and the Central African Republic. Strengthening onchocerciasis elimination efforts in areas with a high prevalence of disease burden is crucial to decrease transmission, morbidity, and mortality. We argue that clinical trials are needed to investigate the safety and efficacy of ivermectin treatment of Onchocerca volvulus-infected pregnant women and children younger than 5 years. Crucially, 6-monthly administration of ivermectin in school-age children at risk of onchocerciasis-associated epilepsy could be achieved by supplementing annual CDTI with an extra round of ivermectin treatment during Child Health Days in schools and/or other distribution sites every year. These strategies would help achieve the elimination of onchocerciasis and its associated disease burden.
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Single-Nucleotide Polymorphism Associates' β-Tubulin Isotype-1 Gene in Onchocerca volvulus Populations in Ivermectin-Treated Communities in Taraba State, Nigeria. Acta Parasitol 2022; 67:267-274. [PMID: 34279775 DOI: 10.1007/s11686-021-00427-y] [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: 01/12/2021] [Accepted: 05/24/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE The occurrence of Single-Nucleotide Polymorphisms (SNPs) associated with repeated ivermectin treatment and sub-optimal responses reported by previous findings is of great concern in Onchocerciasis endemic areas. This study investigated SNPs' occurrence after 15 years of ivermectin intervention in Onchocerciasis endemic communities in two Local Government Areas of Taraba State, Nigeria. METHODS Microfilariae samples were collected by skin snip from individuals treated with ivermectin for 10-15 years of annual distribution and preserved in RNAlater® in a 1.5 ml micro-centrifuge tube. Genomic DNA was extracted from microfilariae and residual skin, amplification in two regions within the β-tubulin gene, sequenced and analyzed for SNPs using Bioinformatics tools. RESULTS Three distinct SNP positions: 1183 (T/G), 1188 (T/C) and 1308 (C/T) on the β-tubulin gene on the targeted 1083-1568 bp fragment, associate's with the ivermectin-treated population. Furthermore, SNPs positions detected in this study are 1730 (A/G) and 1794 (T/G) in the β-tub gene in the 1557-1857 (bp) region. The 1794 (T/G) SNP position (Phe243Val) in the exon within the β-tubulin gene region were observed in this study. CONCLUSION The present study indicates that SNPs are observed in Onchocerca volvulus, thus strengthening the warning that genetic changes could occur in some parasite populations in some ivermectin-treated areas.
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Hong AR, Opoku NO, Weil GJ, Kanza EM, Gyasi ME. New Research Aims to Optimize Therapy Against Onchocerciasis. MISSOURI MEDICINE 2022; 119:55-59. [PMID: 36033145 PMCID: PMC9312456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Onchocerciasis is a parasitic disease that is the second most common cause of infectious blindness in the world, affecting 25 million people, mostly in sub-saharan Africa. Mass drug administration (MDA) with ivermectin has been the mainstay of a successful international effort to reduce the burden of vision loss. Despite improvements in infection rates and blindness through MDA with ivermectin, adult worms are not killed or permanently sterilized by this drug and can live for greater than 10 years. Therefore, new treatments for onchocerciasis are critical to accelerating the rate of elimination of this blinding disease. Here we discuss an ongoing study of a new treatment for onchocerciasis.
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Affiliation(s)
- Augustine R Hong
- John F. Hardesty MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri
| | - Nicholas O Opoku
- Senior Lecturer, School of Public Health, University of Health and Allied Sciences, Ho, Ghana
| | - Gary J Weil
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri
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Lagatie O, Batsa Debrah L, Debrah AY, Stuyver LJ. Whole blood transcriptome analysis in onchocerciasis. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 2:100100. [PMID: 36082138 PMCID: PMC9445278 DOI: 10.1016/j.crpvbd.2022.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/30/2022] [Accepted: 08/02/2022] [Indexed: 11/24/2022]
Abstract
Identifying the molecular mechanisms controlling the host’s response to infection with Onchocerca volvulus is important to understand how the human host controls such parasitic infection. Little is known of the cellular immune response upon infection with O. volvulus. We performed a transcriptomic study using PAXgene-preserved whole blood from 30 nodule-positive individuals and 21 non-endemic controls. It was found that of the 45,042 transcripts that were mapped to the human genome, 544 were found to be upregulated and 447 to be downregulated in nodule-positive individuals (adjusted P-value < 0.05). Pathway analysis was performed on this set of differentially expressed genes, which demonstrated an impact on oxidative phosphorylation and protein translation. Upstream regulator analysis showed that the mTOR associated protein RICTOR appears to play an important role in inducing the transcriptional changes in infected individuals. Functional analysis of the genes affected by infection indicated a suppression of antibody response, Th17 immune response and proliferation of activated T lymphocytes. Multiple regression models were used to select 22 genes that could contribute significantly in the generation of a classifier to predict infection with O. volvulus. For these 22 genes, as well as for 8 reference target genes, validated RT-qPCR assays were developed and used to re-analyze the discovery sample set. These data were used to perform elastic net regularized logistic regression and a panel of 7 genes was found to be the best performing classifier. The resulting algorithm returns a value between 0 and 1, reflecting the predicted probability of being infected. A validation panel of 69 nodule-positive individuals and 5 non-endemic controls was used to validate the performance of this classifier. Based on this validation set only, a sensitivity of 94.2% and a specificity of 60.0% was obtained. When combining the discovery test set and validation set, a sensitivity of 96.0% and a specificity of 92.3% was obtained. Large-scale validation approaches will be necessary to define the intended use for this classifier. Besides the use as marker for infection in MDA efficacy surveys and epidemiological transmission studies, this classifier might also hold potential as pharmacodynamic marker in macrofilaricide clinical trials. Whole blood transcriptome analysis was performed in onchocerciasis patients. Suppression of antibodies, Th17, and proliferation of activated T cells. RICTOR plays an important role in inducing the transcriptional changes. A 7-gene expression classifier was built as a tool for onchocerciasis detection.
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Affiliation(s)
- Ole Lagatie
- Johnson & Johnson Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340 Beerse, Belgium
- Corresponding author.
| | - Linda Batsa Debrah
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Alex Y. Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Lieven J. Stuyver
- Johnson & Johnson Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340 Beerse, Belgium
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Penkunas MJ, Berdou E, Chong SY, Launois P, Rhule ELM, Allotey P. Increasing Knowledge Translation Capacity in Low- and Middle-Income Countries: A Model for Implementation Research Training. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.762966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Most health professionals lack the training and expertise to translate clinical innovations into actionable programs. Even though some public health expert communities understand that even widely proven solutions need to be adapted to the demands and characteristics of diverse health systems and societies to be successful, such knowledge has yet to inform routine public health approaches and practices. Therefore, it should not be a surprise that the “know-do” gap between clinical innovations and their on-the-ground application that implementation research seeks to bridge is pervasive and enduring, particularly in low- and middle-income countries. This article draws on a study of implementation research training courses to highlight the various competencies needed to translate different types of knowledge into action, many of which are not adequately addressed in existing curricula. We utilized a four-phase modified Delphi methodology that included a review of the academic and grey literature, one-on-one interviews with experts, virtual dialogue series with key stakeholders, and peer review of the synthesized results. The resulting areas in need of further development include the ability of learners to work as part of a multidisciplinary team, engage various stakeholders, and communicate research findings to decision-makers. Based on these insights, it is argued that knowledge translation in implementation research is a multi-faceted, multi-level sensemaking and communication activity that takes place throughout the research and research-to policy-processes.
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Risch F, Ritter M, Hoerauf A, Hübner MP. Human filariasis-contributions of the Litomosoides sigmodontis and Acanthocheilonema viteae animal model. Parasitol Res 2021; 120:4125-4143. [PMID: 33547508 PMCID: PMC8599372 DOI: 10.1007/s00436-020-07026-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/20/2020] [Indexed: 12/16/2022]
Abstract
Filariae are vector-borne parasitic nematodes that are endemic worldwide, in tropical and subtropical regions. Important human filariae spp. include Onchocerca volvulus, Wuchereria bancrofti and Brugia spp., and Loa loa and Mansonella spp. causing onchocerciasis (river blindness), lymphatic filariasis (lymphedema and hydrocele), loiasis (eye worm), and mansonelliasis, respectively. It is estimated that over 1 billion individuals live in endemic regions where filarial diseases are a public health concern contributing to significant disability adjusted life years (DALYs). Thus, efforts to control and eliminate filarial diseases were already launched by the WHO in the 1970s, especially against lymphatic filariasis and onchocerciasis, and are mainly based on mass drug administration (MDA) of microfilaricidal drugs (ivermectin, diethylcarbamazine, albendazole) to filarial endemic areas accompanied with vector control strategies with the goal to reduce the transmission. With the United Nations Sustainable Development Goals (SDGs), it was decided to eliminate transmission of onchocerciasis and stop lymphatic filariasis as a public health problem by 2030. It was also requested that novel drugs and treatment strategies be developed. Mouse models provide an important platform for anti-filarial drug research in a preclinical setting. This review presents an overview about the Litomosoides sigmodontis and Acanthocheilonema viteae filarial mouse models and their role in immunological research as well as preclinical studies about novel anti-filarial drugs and treatment strategies.
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Affiliation(s)
- Frederic Risch
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany.
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany.
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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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Campillo JT, Bikita P, Hemilembolo M, Louya F, Missamou F, Pion SDS, Boussinesq M, Chesnais CB. Safety and efficacy of levamisole in loiasis: a randomized, placebo-controlled, double-blind clinical trial. Clin Infect Dis 2021; 75:19-27. [PMID: 34651190 PMCID: PMC9402607 DOI: 10.1093/cid/ciab906] [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: 09/09/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Individuals with high microfilarial densities (MFD) of Loa loa are at risk of developing serious adverse events (SAEs) after ivermectin treatment. Pretreatment with drugs progressively reducing Loa MFD below the risk threshold might help prevent these SAEs. We assessed the safety and efficacy of levamisole for this purpose. METHODS A double-blind, randomized, placebo-controlled, MFD-ascending trial was conducted in the Republic of the Congo. Participants were treated in 3 cohorts defined by pretreatment MFD and levamisole dose (Cohort 1: 1.0 kg and 1.5 mg/kg, Cohorts 2 and 3: 2.5 mg/kg). Safety outcomes were occurrence of SAE and AE frequency during the first week. The efficacy outcomes were MFD reduction from baseline and proportions of individuals with at least 40% and 80% MFD reduction at day 2 (D2), D7 and D30. RESULTS The two lowest doses (1.0 mg/kg and 1.5 mg/kg) caused no SAE but were ineffective. Compared to placebo, 2.5 mg/kg levamisole caused more mild AEs (10/85 vs. 3/85, P = .018), a higher median reduction from baseline to D2 (-12.9% vs. + 15.5%, P < .001), D7 (-4.9% vs. +18.7%, P < .001) and D30 (-0.5% vs. +13.5%, P = .036) and a higher percentage of participants with >40% MFD reduction at D2 (17.5% vs. 1.2%, P < .001), D7 (11.8% vs. 6.3%, P = .269) and D30 (18.5% vs. 9.6%, P = .107). CONCLUSIONS A single 2.5 mg/kg levamisole dose induces a promising transient reduction in Loa loa MFD and should encourage testing different regimens.
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Affiliation(s)
- Jérémy T Campillo
- UMI 233 TransVIHMI, Université de Montpellier, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Montpellier, France
| | - Paul Bikita
- Programme National de Lutte contre l'Onchocercose, Direction de l'Épidémiologie et de la Lutte contre la Maladie, Ministère de la Santé et de la Population, Brazzaville, Republic of the Congo
| | - Marlhand Hemilembolo
- Programme National de Lutte contre l'Onchocercose, Direction de l'Épidémiologie et de la Lutte contre la Maladie, Ministère de la Santé et de la Population, Brazzaville, Republic of the Congo
| | - Frédéric Louya
- Programme National de Lutte contre l'Onchocercose, Direction de l'Épidémiologie et de la Lutte contre la Maladie, Ministère de la Santé et de la Population, Brazzaville, Republic of the Congo
| | - François Missamou
- Programme National de Lutte contre l'Onchocercose, Direction de l'Épidémiologie et de la Lutte contre la Maladie, Ministère de la Santé et de la Population, Brazzaville, Republic of the Congo
| | - Sébastien D S Pion
- UMI 233 TransVIHMI, Université de Montpellier, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Montpellier, France
| | - Michel Boussinesq
- UMI 233 TransVIHMI, Université de Montpellier, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Montpellier, France
| | - Cédric B Chesnais
- UMI 233 TransVIHMI, Université de Montpellier, Institut de Recherche pour le Développement (IRD), INSERM Unité 1175, Montpellier, France
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Evaluating the diagnostic test accuracy of molecular xenomonitoring methods for characterising the community burden of Onchocerciasis. PLoS Negl Trop Dis 2021; 15:e0009812. [PMID: 34637436 PMCID: PMC8509893 DOI: 10.1371/journal.pntd.0009812] [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: 05/05/2021] [Accepted: 09/13/2021] [Indexed: 11/19/2022] Open
Abstract
Background Molecular xenomonitoring (MX), the detection of parasite nucleic acid in the vector population, is recommended for onchocerciasis surveillance in elimination settings. However, the sensitivity of MX for detecting onchocerciasis-positive communities has not previously been evaluated. MX may have additional applications for control programmes but its utility is restricted by a limited understanding of the relationship between MX results and human prevalence. Methods We conducted a systematic review of studies reporting the prevalence of Onchocerca volvulus DNA in wild-caught Simulium spp. flies (MX rate) and corresponding prevalence of microfilaria (mf) in humans. We evaluated the sensitivity of MX for detecting onchocerciasis-positive communities and describe the characteristics of studies with reduced sensitivity. We conducted a linear regression to evaluate the relationship between mf prevalence and MX rate. Results We identified 15 relevant studies, with 13 studies comprising 34 study communities included in the quantitative analyses. Most communities were at advanced stages towards elimination and had no or extremely low human prevalence. MX detected positive flies in every study area with >1% mf prevalence, with the exception of one study conducted in the Venezuelan Amazonian focus. We identified a significant relationship between the two measurements, with mf prevalence accounting for half of the variation in MX rate (R2 0.50, p<0.001). Conclusion MX is sensitive to communities with ongoing onchocerciasis transmission. It has potential to predict human mf prevalence, but further data is required to understand this relationship, particularly from MX surveys conducted earlier in control programmes before transmission has been interrupted. Traditional surveillance of onchocerciasis relies on the detection of Onchocerca volvulus microfilaria or antibodies in human skin or blood samples. Molecular xenomonitoring, the detection of parasite nucleic acid in vector insects, provides a non-invasive alternative. The sensitivity of molecular xenomonitoring to areas where infected people are found has not previously been evaluated and the extent to which xenomonitoring can be used to predict human prevalence is unknown. We searched for previous studies that reported the infection rates in humans and detection rates in black flies, finding 15 studies comprising 34 study communities that contributed to our analyses. Studies were conducted across Africa and the Americas, mostly in areas of very low prevalence. The findings show molecular xenomonitoring was sensitive to areas with greater than 1% microfilaria prevalence in the human population, indicating that molecular xenomonitoring is effective at detecting ongoing transmission. We further found evidence that infection rates in humans and detection rates in flies were related, providing scope for the use of xenomonitoring to predict human prevalence. With further research to better understand this relationship, control programmes may be able to use xenomonitoring for other purposes such as identifying areas that require intervention and monitoring the impact of treatments.
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Akumtoh DN, Njouendou AJ, Metuge HM, Sjoberg HT, Pionnier NP, Chunda VC, Gandjui NVT, Ndzeshang LB, Fombad FF, Abong RA, Enyong PA, Fru-Cho J, Esum ME, Ritter M, Taylor MJ, Turner JD, Wanji S. Onchocerca ochengi male worms implanted in SCID mice and Gerbil: Relationship between microfilaridermia status of cows, nodular worm viability and fertility and worm survival in the rodents. Exp Parasitol 2021; 229:108143. [PMID: 34437906 PMCID: PMC8518880 DOI: 10.1016/j.exppara.2021.108143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 05/06/2021] [Accepted: 08/16/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Current treatment options for onchocerciasis are sub-optimal, prompting research and development of a safe cure (macrofilaricide). Onchocerca ochengi, a parasite of cattle, is used as a close surrogate for the human parasite O. volvulus in a murine model for pre-clinical screening of macrofilaricides. Skin from naturally infected cattle have been used in previous studies as a reliable source of parasite material. However, there is limited knowledge on how source-related factors such as the microfilaridermia status of the cattle, the nodule load and nodular worm viability may affect survival of male O. ochengi worms implanted in the rodent hosts. Such relationships were investigated in this study. METHODS Dermal tissue and nodules were obtained from Gudali cattle, dissected and cultured to obtain migrating microfilariae (mf) and male worms. Emerged male worms were implanted into SCID mice and Gerbils (Meriones unguiculatus) and recovery rates were determined upon 42 days post implantation. Finally, nodules were processed for histology and embryogram analyses to assess the nodular worm viability and fertility, respectively. RESULTS Of the 69 cattle sampled, 24 (34.8%) were mf+ and 45 (65.2%) were mf-. The mean nodule loads were 180.5 ± 117.7 (mf+) and 110.6 ± 102.7 (mf-) (p = 0.0186). The mean male worm harvest from nodules were 76.8 ± 120.3 and 47.2 ± 33.4 (p = 0.2488) for mf+ and mf- cattle, respectively. The number of male worms per 100 nodules were 57/100 and 46/100 nodules for mf+ and mf- cows, respectively. Female worms from nodules of mf- cows had higher counts of both normal and abnormal embryos with higher proportions of dead nodular worms evinced by histology compared to those from mf+ cows. A total of 651 worms were implanted into mice and gerbils, out of which 129 (19.81%) were recovered. Logistic regression analysis indicated that the microfilaridermia status of the cattle (presence of mf) (OR = 4.3319; P = 0.001) is the single most important predictor of the success of male worm recovery after implantation into rodents. CONCLUSION Microfilaridermic cattle provide a promising source of adult O. ochengi. Male worms from this group of cattle have a better success rate of survival in a murine implant model. Nevertheless, in the programmatic point of view, amicrofilaridermic Gudali cattle would still constitute an important source of O. ochengi male worms with relatively good viability after implantation into rodents.
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Affiliation(s)
- Desmond N Akumtoh
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Abdel J Njouendou
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Buea, Cameroon.
| | - Haelly M Metuge
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Hanna T Sjoberg
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nicolas P Pionnier
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Valerine C Chunda
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Narcisse Victor T Gandjui
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Lontum B Ndzeshang
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Fanny F Fombad
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon.
| | - Raphael A Abong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Peter A Enyong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Jerome Fru-Cho
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Mathias E Esum
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany; German Center for Infection Research (DZIF), Bonn - Cologne Partner Site, Bonn, Germany.
| | - Mark J Taylor
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Joseph D Turner
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon; Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
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Vinkeles Melchers NVS, Stolk WA, Murdoch ME, Pedrique B, Kloek M, Bakker R, de Vlas SJ, Coffeng LE. How does onchocerciasis-related skin and eye disease in Africa depend on cumulative exposure to infection and mass treatment? PLoS Negl Trop Dis 2021; 15:e0009489. [PMID: 34115752 PMCID: PMC8221783 DOI: 10.1371/journal.pntd.0009489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 06/23/2021] [Accepted: 05/19/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Onchocerciasis (river-blindness) in Africa is targeted for elimination through mass drug administration (MDA) with ivermectin. Onchocerciasis may cause various types of skin and eye disease. Predicting the impact of MDA on onchocercal morbidity is useful for future policy development. Here, we introduce a new disease module within the established ONCHOSIM model to predict trends over time in prevalence of onchocercal morbidity. METHODS We developed novel generic model concepts for development of symptoms due to cumulative exposure to dead microfilariae, accommodating both reversible (acute) and irreversible (chronic) symptoms. The model was calibrated to reproduce pre-control age patterns and associations between prevalences of infection, eye disease, and various types of skin disease as observed in a large set of population-based studies. We then used the new disease module to predict the impact of MDA on morbidity prevalence over a 30-year time frame for various scenarios. RESULTS ONCHOSIM reproduced observed age-patterns in disease and community-level associations between infection and disease reasonably well. For highly endemic settings with 30 years of annual MDA at 60% coverage, the model predicted a 70% to 89% reduction in prevalence of chronic morbidity. This relative decline was similar with higher MDA coverage and only somewhat higher for settings with lower pre-control endemicity. The decline in prevalence was lowest for mild depigmentation and visual impairment. The prevalence of acute clinical manifestations (severe itch, reactive skin disease) declined by 95% to 100% after 30 years of annual MDA, regardless of pre-control endemicity. CONCLUSION We present generic model concepts for predicting trends in acute and chronic symptoms due to history of exposure to parasitic worm infections, and apply this to onchocerciasis. Our predictions suggest that onchocercal morbidity, in particular chronic manifestations, will remain a public health concern in many epidemiological settings in Africa, even after 30 years of MDA.
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Affiliation(s)
| | - Wilma A. Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Michele E. Murdoch
- Department of Dermatology, West Herts Hospitals NHS Trust, Watford General Hospital, Watford, Hertfordshire, United Kingdom
| | - Belén Pedrique
- Drugs for Neglected Diseases initiative (DNDi), Geneva, Switzerland
| | - Marielle Kloek
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Roel Bakker
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Dolo H, Coulibaly YI, Sow M, Dembélé M, Doumbia SS, Coulibaly SY, Sangare MB, Dicko I, Diallo AA, Soumaoro L, Coulibaly ME, Diarra D, Colebunders R, Nutman TB, Walker M, Basáñez MG. Serological Evaluation of Onchocerciasis and Lymphatic Filariasis Elimination in the Bakoye and Falémé Foci, Mali. Clin Infect Dis 2021; 72:1585-1593. [PMID: 32206773 PMCID: PMC8096229 DOI: 10.1093/cid/ciaa318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Indexed: 11/14/2022] Open
Abstract
Background Ivermectin-based onchocerciasis elimination, reported in 2009–2012, for Bakoye and Falémé, Mali, supported policy-shifting from morbidity control to elimination of transmission (EOT). These foci are coendemic with lymphatic filariasis (LF). In 2007–2016 mass ivermectin plus albendazole administration was implemented. We report Ov16 (onchocerciasis) and Wb123 (LF) seroprevalence after 24–25 years of treatment to determine if onchocerciasis EOT and LF elimination as a public health problem (EPHP) have been achieved. Methods The SD Bioline Onchocerciasis/LF Ig[immunoglobulin]G4 biplex rapid diagnostic test (RDT) was used in 2186 children aged 3–10 years in 13 villages (plus 2 hamlets) in Bakoye and in 2270 children in 15 villages (plus 1 hamlet) in Falémé. In Bakoye, all-age serosurveys were conducted in 3 historically hyperendemic villages (1867 individuals aged 3 -78 years). Results In Bakoye, IgG4 seropositivity was 0.27% (95% confidence interval [CI] = .13%–.60%) for both Ov16 and Wb123 antigens. In Falémé, Ov16 and Wb123 seroprevalence was 0.04% (95% CI = .01%–.25%) and 0.09% (95% CI = .02%–.32%), respectively. Ov16-seropositive children were from historically meso/hyperendemic villages. Ov16 positivity was <2% in ≤14 year-olds, and 16% in ≥40 year-olds. Wb123 seropositivity was <2% in ≤39 year-olds, reaching 3% in ≥40 year-olds. Conclusions Notwithstanding uncertainty in the biplex RDT sensitivity, Ov16 and Wb123 seroprevalence among children in Bakoye and Falémé is consistent with EOT (onchocerciasis) and EPHP (LF) since stopping treatment in 2016. The few Ov16-seropositive children should be skin-snip polymerase chain reaction tested and followed up.
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Affiliation(s)
- Housseini Dolo
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali.,Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Yaya I Coulibaly
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali.,Centre National d'Appui à la lutte contre la Maladie, Bamako, Mali
| | - Moussa Sow
- Programme National de Lutte contre l'Onchocercose, Bamako, Mali
| | - Massitan Dembélé
- Programme National d'Elimination de la Filariose Lymphatique, Bamako, Mali
| | - Salif S Doumbia
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Siaka Y Coulibaly
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Moussa B Sangare
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Ilo Dicko
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Abdallah A Diallo
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Lamine Soumaoro
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Michel E Coulibaly
- Lymphatic Filariasis Research Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | | | | | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Martin Walker
- Department of Pathobiology and Population Sciences and London Centre for Neglected Tropical Disease Research, Royal Veterinary College, Hatfield, United Kingdom
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research, MRC Centre for Global Infectious Disease Analysis, Imperial College London, United Kingdom
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Nikièma AS, Koala L, Sondo AK, Post RJ, Paré AB, Kafando CM, Kambiré RS, Sow B, Bougouma C, Dabiré RK, Traoré S. The impact of ivermectin on onchocerciasis in villages co-endemic for lymphatic filariasis in an area of onchocerciasis recrudescence in Burkina Faso. PLoS Negl Trop Dis 2021; 15:e0009117. [PMID: 33647010 PMCID: PMC7920372 DOI: 10.1371/journal.pntd.0009117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 01/08/2021] [Indexed: 11/18/2022] Open
Abstract
In Burkina Faso, onchocerciasis was no longer a public health problem when the WHO Onchocerciasis Control Programme in West Africa closed at the end in 2002. However, epidemiological surveillance carried out from November 2010 to February of 2011, showed a recrudescence of infection in the Cascades Region. This finding was made at a time when ivermectin, a drug recommended for the treatment of both onchocerciasis and lymphatic filariasis, had been distributed in this area since 2004 for the elimination of lymphatic filariasis. It was surprising that ivermectin distributed for treating lymphatic filariasis had not prevented the recrudescence of onchocerciasis. Faced with this situation, the aim of our study was to evaluate the effectiveness of ivermectin on the onchocerciasis parasite. The percentage reduction in microfilarial load after treatment with ivermectin was used as a proxy measure for assessing possible resistance. A cohort study was carried out with 130 individuals who had tested positive for microfilariae of Onchocerca volvulus in 2010 using microscopic examination of skin-snip biopsies from five endemic villages. Subjects were followed from July 2011 to June 2012. The microfilarial load of each individual was enumerated by skin-snip biopsy in 2010, prior to the first ivermectin treatment against onchocerciasis under community guidelines. All individuals received two ivermectin treatments six months apart. In 2012, the microfilarial loads were determined again, six months after the second round of ivermectin and the reductions in parasite loads were calculated to measure the impact of the drug. The percentage reduction of the microfilarial loads ranged from 87% to 98% in the villages. In all villages, there was a statistically significant difference between the average microfilarial loads in 2010 and 2012. The level of reduction of microfilarial loads suggests that ivermectin is effective against the recrudescent population of O. volvulus in Cascades Region of Burkina Faso. Further investigations would be necessary to determine the causes of the recrudescence of onchocerciasis. (For French language abstract, see S1 Alternative Language Abstract—Translation of the Abstract into French by the authors.) In 1989, onchocerciasis had been eliminated as a public health problem throughout Burkina Faso by insecticidal treatment of vector breeding sites, but epidemiological surveys along the Comoé River in 2010/11 revealed a recrudescence of infection rates. Modern onchocerciasis control is based upon mass drug administration using ivermectin, and hence biannual distribution of ivermectin was instigated to bring the recrudescence under control. However, it was by no means certain that this was an appropriate strategy because the area was already under mass drug administration with ivermectin since 2004 to eliminate lymphatic filariasis. Onchocerca volvulus adult females with reduced susceptibility to ivermectin have been reported from Ghana, and if the Burkinabe recrudescence was the result of reduced susceptibility, ivermectin might fail to solve the problem. To test this, a cohort of positive people was examined for the density of microfilariae in their skin six months after the second round of ivermectin. The reduction in microfilarial load was substantial, and comparable to levels found in ivermectin-naïve populations (normally assumed to be susceptible), but greater than Ghanaian populations with reduced susceptibility. On this basis we conclude that the Burkinabe recrudescence was not the result of parasites with reduced susceptibility to ivermectin, and biannual treatment remains the chosen means to deal with the recrudescence.
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Affiliation(s)
- Achille S. Nikièma
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l’Ouest, Bobo Dioulasso, Burkina Faso
- * E-mail:
| | - Lassane Koala
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l’Ouest, Bobo Dioulasso, Burkina Faso
| | - Apoline K. Sondo
- Université Ouaga I Pr Joseph ki-Zerbo, Unité de Formation et de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso
| | - Rory J. Post
- Disease Control Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- School of Biological & Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Alain B. Paré
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National lutte contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Claude M. Kafando
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National lutte contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Roger S. Kambiré
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National lutte contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Bazoumana Sow
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l’Ouest, Bobo Dioulasso, Burkina Faso
| | - Clarisse Bougouma
- Ministère de la Santé, Direction de la Protection de la Santé de la Population, Programme National lutte contre les Maladies Tropicales Négligées, Ouagadougou, Burkina Faso
| | - Roch K. Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l’Ouest, Bobo Dioulasso, Burkina Faso
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Progress towards onchocerciasis elimination in Côte d'Ivoire: A geospatial modelling study. PLoS Negl Trop Dis 2021; 15:e0009091. [PMID: 33566805 PMCID: PMC7875389 DOI: 10.1371/journal.pntd.0009091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/01/2021] [Indexed: 11/19/2022] Open
Abstract
Background Côte d’Ivoire has had 45 years of intervention for onchocerciasis by vector control (from 1975 to 1991), ivermectin mass drug administration (MDA) (from 1992 to 1994) and community directed treatment with ivermectin (CDTi) from 1995 to the present. We modeled onchocerciasis endemicity during two time periods that correspond to the scale up of vector control and ivermectin distribution, respectively. This analysis illustrates progress towards elimination during these periods, and it has identified potential hotspots areas that are at risk for ongoing transmission. Methods and findings The analysis used Ministry of Health skin snip microfilaria (MF) prevalence and intensity data collected between 1975 and 2016. Socio-demographic and environmental factors were incorporated into a predictive, machine learning algorithm to create continuous maps of onchocerciasis endemicity. Overall predicted mean MF prevalence decreased from 51.8% circa 1991 to 3.9% circa 2016. The model predicted infection foci with higher prevalence in the southern region of the country. Predicted mean community MF load (CMFL) decreased from 10.1MF/snip circa 1991 to 0.1MF/snip circa 2016. Again, the model predicts foci with higher Mf densities in the southern region. For assessing model performance, the root mean squared error and R2 values were 1.14 and 0.62 respectively for a model trained with data collected prior to 1991, and 1.28 and 0.57 for the model trained with infection survey data collected later, after the introduction of ivermectin. Finally, our models show that proximity to permanent inland bodies of water and altitude were the most informative variables that correlated with onchocerciasis endemicity. Conclusion/Significance This study further documents the significant reduction of onchocerciasis infection following widespread use of ivermectin for onchocerciasis control in Côte d’Ivoire. Maps produced predict areas at risk for ongoing infection and transmission. Onchocerciasis might be eliminated in Côte d’Ivoire in the future with a combination of sustained CDTi with high coverage, active surveillance, and close monitoring for persistent infection in previously hyper-endemic areas. Côte d’Ivoire is endemic for onchocerciasis (also known as “river blindness”). This neglected tropical disease is transmitted by biting black flies that breed in fast flowing rivers. From 1975 to 1991, onchocerciasis control was based on weekly aerial spraying of the insecticide temephos, on black fly breeding sites. Vector control, however, was mostly focused on the northern and central parts of the country. From 1992 to present, mass treatment with ivermectin was implemented in all endemic areas, including forested regions in the south. Here we present the first geospatial estimates of onchocerciasis endemicity over time. Using the machine learning algorithm quantile regression forest, we implemented models to: identify important socio-demographic and environmental factors that correlate with onchocerciasis infection; predict the prevalence and density of infection in areas without ground-truth data; delineate remaining infection hotspots. Our results show that Côte d’Ivoire has made very significant progress in reducing infection parameters over time, and they may help to inform future interventions to achieve the goal of onchocerciasis elimination in Côte d’Ivoire.
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Ramírez C, Herrera-Paz EF, Peralta G, Rodríguez G, Durón RM. Is ivermectin ready to be part of a public health policy for COVID-19 prophylaxis? EClinicalMedicine 2021; 32:100744. [PMID: 33558858 PMCID: PMC7859718 DOI: 10.1016/j.eclinm.2021.100744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Céleo Ramírez
- Consorcio de Investigadores COVID Honduras, Tegucigalpa 11101, Honduras
- Hospital del Valle, Bulevar del Norte, 8 calle NE San Pedro Sula 21101, Honduras
| | - Edwin F. Herrera-Paz
- Consorcio de Investigadores COVID Honduras, Tegucigalpa 11101, Honduras
- Universidad Católica de Honduras, Escuela de Medicina, Campus San Pedro y San Pablo, San Pedro Sula 21102, Honduras
- Corresponding author.
| | - Guímel Peralta
- Consorcio de Investigadores COVID Honduras, Tegucigalpa 11101, Honduras
- Facultad de Ciencias de la Salud, Universidad Tecnológica Centroamericana (UNITEC), Tegucigalpa 11101, Honduras
| | - Gaspar Rodríguez
- Consorcio de Investigadores COVID Honduras, Tegucigalpa 11101, Honduras
- Instituto Hondureño del Seguro Social, Hospital de Especialidades, Barrio la Granja, Tegucigalpa, Honduras
| | - Reyna M. Durón
- Consorcio de Investigadores COVID Honduras, Tegucigalpa 11101, Honduras
- Facultad de Ciencias de la Salud, Universidad Tecnológica Centroamericana (UNITEC), Tegucigalpa 11101, Honduras
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