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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Satapathy P, Kaur G, Asumah MN, Ainavi II, Rustagi S, Pradhan KB, Al-Qaim ZH, Sah R, Padhi BK. Fighting the neglected tropical disease: Cameroon's battle against river blindness. Trans R Soc Trop Med Hyg 2024; 118:e1-e2. [PMID: 37861331 DOI: 10.1093/trstmh/trad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023] Open
Affiliation(s)
- Prakasini Satapathy
- Center for Global Health Research, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India
- School of Pharmacy, Graphic Era Hill University, Dehradun 248001, India
| | - Gurmanjeet Kaur
- Department of Community Medicine, Government Medical College, and Rajindra Hospital, Patiala 147001 Punjab, India
| | - Mubarick Nungbaso Asumah
- Ministry of Health, Nurses' and Midwives' Training College, P.O. Box 565, Tamale, Northern Region, Ghana
| | - Isah Idris Ainavi
- Department of Chemical Pathology and Immunology, Kaduna State University, Kaduna, Nigeria
| | - Sarvesh Rustagi
- School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttarakhand, India
| | - Keerti Bhusan Pradhan
- Department of Healthcare Management, Chitkara Business School, Chitkara University Punjab, Patiala 140401, India
| | - Zahraa Haleem Al-Qaim
- Department of Anesthesia Techniques, Al-Mustaqbal University College, 51001 Hillah, Babylon, Iraq
| | - Ranjit Sah
- Tribhuvan University Teaching Hospital, Kathmandu 46000, Nepal
- Department of Clinical Microbiology, DY Patil Medical College, Hospital and Research Centre, DY Patil Vidyapeeth, Pune 411000, Maharashtra, India
- Department of Public Health Dentistry, Dr D.Y. Patil Dental College and Hospital, Dr D.Y. Patil Vidyapeeth, Pune 411018, Maharashtra, India
| | - Bijaya K Padhi
- Department of Community Medicine and School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
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Jesudason T. A new key-player for onchocerciasis elimination. Lancet Infect Dis 2023; 23:413. [PMID: 36965498 DOI: 10.1016/s1473-3099(23)00151-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2023]
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Smith ME, Bilal S, Lakwo TL, Habomugisha P, Tukahebwa E, Byamukama E, Katabarwa MN, Richards FO, Cupp EW, Unnasch TR, Michael E. Accelerating river blindness elimination by supplementing MDA with a vegetation "slash and clear" vector control strategy: a data-driven modeling analysis. Sci Rep 2019; 9:15274. [PMID: 31649285 PMCID: PMC6813336 DOI: 10.1038/s41598-019-51835-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 10/09/2019] [Indexed: 01/08/2023] Open
Abstract
Attention is increasingly focusing on how best to accelerate progress toward meeting the WHO's 2030 goals for neglected tropical diseases (NTDs). For river blindness, a major NTD targeted for elimination, there is a long history of using vector control to suppress transmission, but traditional larvicide-based approaches are limited in their utility. One innovative and sustainable approach, "slash and clear", involves clearing vegetation from breeding areas, and recent field trials indicate that this technique very effectively reduces the biting density of Simulium damnosum s.s. In this study, we use a Bayesian data-driven mathematical modeling approach to investigate the potential impact of this intervention on human onchocerciasis infection. We developed a novel "slash and clear" model describing the effect of the intervention on seasonal black fly biting rates and coupled this with our population dynamics model of Onchocerca volvulus transmission. Our results indicate that supplementing annual drug treatments with "slash and clear" can significantly accelerate the achievement of onchocerciasis elimination. The efficacy of the intervention is not very sensitive to the timing of implementation, and the impact is meaningful even if vegetation is cleared only once per year. As such, this community-driven technique will represent an important option for achieving and sustaining O. volvulus elimination.
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Affiliation(s)
- Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Shakir Bilal
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Thomson L Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | | | | | | | - Eddie W Cupp
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Thomas R Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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Loum D, Cozart D, Lakwo T, Habomugisha P, Jacob B, Cupp EW, Unnasch TR. Optimization and evaluation of the Esperanza Window Trap to reduce biting rates of Simulium damnosum sensu lato in Northern Uganda. PLoS Negl Trop Dis 2019; 13:e0007558. [PMID: 31310607 PMCID: PMC6634373 DOI: 10.1371/journal.pntd.0007558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/18/2019] [Indexed: 11/29/2022] Open
Abstract
Background Onchocerciasis, or river blindness, has historically been an important cause of blindness, skin disease and economic disruption in Africa and the Americas. It is caused by the filarial parasite Onchocerca volvulus, which is transmitted by black flies in the genus Simulium. Over the past decade, several international programs have been formed to control, or more recently eliminate onchocerciasis, using mass drug administration (MDA) of ivermectin. However, in many areas of Africa (particularly those which are endemic for the eyeworm, Loa loa, or where vector densities are very high) ivermectin MDA alone will not be sufficient to achieve elimination. In these situations, additional interventions may be necessary. Methodology/Principal findings The Esperanza Window trap (EWT), a simple trap originally developed to replace human landing collections for entomological surveillance of O. volvulus transmission was optimized, resulting in a 17-fold improvement in trap performance. The optimized trap was tested in trials in schools and in agricultural fields to determine if it could reduce vector biting locally. The traps resulted in a 90% reduction in biting in the school setting. In the field setting, results varied. In one location, the traps reduced biting by roughly 50%, while in a separate trial, the traps did not significantly reduce the biting rate. Examination of the two settings suggested that trap placement may be critical to their success. Conclusions/Significance These results suggest that the optimized EWT might be capable of reducing local vector black fly biting in areas commonly frequented by residents. Together with other recently developed methods of community directed vector control, the traps may augment ivermectin MDA, bringing the goal of onchocerciasis elimination within reach in much of Africa. Onchocerciasis or river blindness is historically one of the most important causes of blindness and skin disease in the developing world. It is caused by infection with the filarial parasite Onchocerca volvulus. The finding that ivermectin was an effective and safe treatment for onchocerciasis and the decision by its manufacturer to donate it to treat this infection spawned the development of programs to eliminate river blindness through mass drug administration of ivermectin to the afflicted populations. This has dramatically reduced the prevalence of onchocerciasis worldwide and has resulted in its near elimination in the Americas. But ivermectin alone will not eliminate river blindness in much of Africa; additional interventions are necessary. Here we report the optimization of a simple trap for the black fly vector of O. volvulus and show that these traps can dramatically reduce vector biting in some settings. Together with other recently developed community directed methods of vector control, these traps may augment the effect of the ivermectin distribution programs, bringing the goal of elimination within reach in much of Africa.
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Affiliation(s)
- Denis Loum
- Nwoya District Local Government, Nwoya, Uganda
| | - Devon Cozart
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Benjamin Jacob
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Eddie W. Cupp
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Thomas R. Unnasch
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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Dadzie Y, Amazigo UV, Boatin BA, Sékétéli A. The need for evidence-based strategies and tools for onchocerciasis elimination in Africa. Infect Dis Poverty 2019; 8:62. [PMID: 31303174 PMCID: PMC6628483 DOI: 10.1186/s40249-019-0574-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/28/2019] [Indexed: 11/10/2022] Open
Abstract
In a recent article we discussed the feasibility of onchocerciasis elimination in Africa by 2025. We expressed concern that elimination may be impeded by failure to build on the lessons learned in the African onchocerciasis control programmes and the introduction of strategies and tools from the Americas. Richards et al. and Cupp et al. wrote to refute our concern and described recent achievements with stopping treatment in some areas.In this response, we discuss their arguments which did not convince us. We point out several scientific flaws in the American conceptual framework of elimination which has led to longer periods of treatment than necessary, and in the use of an arbitrary threshold for stopping treatment. We show that recent achievements fall significantly short of what would be needed to achieve onchocerciasis elimination by 2025.We conclude our response by advocating for a more objective and inclusive debate on strategies and tools for onchocerciasis elimination.
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Affiliation(s)
| | - Uche V. Amazigo
- P. O. Box 3397, Main Post Office, Okpara Avenue, Enugu, Nigeria
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Gebrezgabiher G, Mekonnen Z, Yewhalaw D, Hailu A. Reaching the last mile: main challenges relating to and recommendations to accelerate onchocerciasis elimination in Africa. Infect Dis Poverty 2019; 8:60. [PMID: 31269966 PMCID: PMC6609392 DOI: 10.1186/s40249-019-0567-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 06/10/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Onchocerciasis (river blindness), caused by the filarial worm species Onchocerca volvulus, is a serious vector-borne neglected tropical disease (NTD) of public health and socioeconomic concern. It is transmitted through the bite of black flies of the genus Simulium, and manifested in dermal and ocular lesions. Ninety-nine percent of the total global risk and burden of onchocerciasis is in Africa. This scoping review examines the key challenges related to the elimination of onchocerciasis by 2020-2025 in Africa, and proposes recommendations to overcome the challenges and accelerate disease elimination. To find relevant articles published in peer-reviewed journals, a search of PubMed and Google Scholar databases was carried out. MAIN TEXT Rigorous regional interventions carried out to control and eliminate onchocerciasis in the past four decades in Africa have been effective in bringing the disease burden under control; it is currently not a public health problem in most endemic areas. Notably, transmission of the parasite is interrupted in some hyperendemic localities. Recently, there has been a policy shift from control to complete disease elimination by 2020 in selected countries and by 2025 in the majority of endemic African countries. The WHO has published guidelines for stopping mass drug administration (MDA) and verifying the interruption of transmission and elimination of human onchocerciasis. Therefore, countries have revised their plans, established a goal of disease elimination in line with an evidence based decision to stop MDA and verify elimination, and incorporated it into their NTDs national master plans. Nevertheless, challenges remain pertaining to the elimination of onchocerciasis in Africa. The challenge we review in this paper are: incomplete elimination mapping of all transmission zones, co-endemicity of onchocerciasis and loiasis, possible emergence of ivermectin resistance, uncoordinated cross-border elimination efforts, conflict and civil unrest, suboptimal program implementation, and technical and financial challenges. This paper also proposes recommendations to overcome the challenges and accelerate disease elimination. These are: a need for complete disease elimination mapping, a need for collaborative elimination activities between national programs, a need for a different drug distribution approach in conflict-affected areas, a need for routine monitoring and evaluation of MDA programs, a need for implementing alternative treatment strategies (ATSs) in areas with elimination anticipated beyond 2025, and a need for strong partnerships and continued funding. CONCLUSIONS National programs need to regularly monitor and evaluate the performance and progress of their interventions, while envisaging the complete elimination of onchocerciasis from their territory. Factors hindering the targeted goal of interruption of parasite transmission need to be identified and remedial actions should be taken. If possible and appropriate, ATSs need to be implemented to accelerate disease elimination by 2025.
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Affiliation(s)
- Gebremedhin Gebrezgabiher
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
- College of Veterinary Medicine, Samara University, Samara, Ethiopia
| | - Zeleke Mekonnen
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, 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
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Colebunders R, Siewe Fodjo JN, Hopkins A, Hotterbeekx A, Lakwo TL, Kalinga A, Logora MY, Basáñez MG. From river blindness to river epilepsy: Implications for onchocerciasis elimination programmes. PLoS Negl Trop Dis 2019; 13:e0007407. [PMID: 31318857 PMCID: PMC6638735 DOI: 10.1371/journal.pntd.0007407] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | | | - Adrian Hopkins
- Neglected and Disabling Diseases of Poverty Consultant, Kent, United Kingdom
| | - An Hotterbeekx
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Thomson L. Lakwo
- Neglected Tropical Diseases Control Programme, Ministry of Health, Kampala, Uganda
| | - Akili Kalinga
- National institute for Medical Research, Ministry of Health, Dar es Salaam, Tanzania
| | - Makoy Yibi Logora
- Neglected Tropical Diseases Unit, Ministry of Health, Juba, South Sudan
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis (MRC-GIDA), Imperial College London, London, United Kingdom
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Colebunders R, Basáñez MG, Siling K, Post RJ, Rotsaert A, Mmbando B, Suykerbuyk P, Hopkins A. From river blindness control to elimination: bridge over troubled water. Infect Dis Poverty 2018; 7:21. [PMID: 29587844 PMCID: PMC5872540 DOI: 10.1186/s40249-018-0406-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 03/12/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND An estimated 25 million people are currently infected with onchocerciasis (a parasitic infection caused by the filarial nematode Onchocerca volvulus and transmitted by Simulium vectors), and 99% of these are in sub-Saharan Africa. The African Programme for Onchocerciasis Control closed in December 2015 and the World Health Organization has established a new structure, the Expanded Special Project for the Elimination of Neglected Tropical Diseases for the coordination of technical support for activities focused on five neglected tropical diseases in Africa, including onchocerciasis elimination. AIMS In this paper we argue that despite the delineation of a reasonably well-defined elimination strategy, its implementation will present particular difficulties in practice. We aim to highlight these in an attempt to ensure that they are well understood and that effective plans can be laid to solve them by the countries concerned and their international partners. CONCLUSIONS A specific concern is the burden of disease caused by onchocerciasis-associated epilepsy in hyperendemic zones situated in countries experiencing difficulties in strengthening their onchocerciasis control programmes. These difficulties should be identified and programmes supported during the transition from morbidity control to interruption of transmission and elimination.
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Affiliation(s)
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Imperial College London, London, UK
| | - Katja Siling
- Institute of Tropical Medicine, Antwerp, Belgium
- London School of Hygiene & Tropical Medicine, London, UK
| | - Rory J. Post
- London School of Hygiene & Tropical Medicine, London, UK
- Liverpool John Moores University, Liverpool, UK
| | - Anke Rotsaert
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Bruno Mmbando
- National Institute for Medical Research, Tanga, Tanzania
| | | | - Adrian Hopkins
- Neglected and Disabling diseases of Poverty Consultant, Gravesend, Kent, UK
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Komlan K, Vossberg PS, Gantin RG, Solim T, Korbmacher F, Banla M, Padjoudoum K, Karabou P, Köhler C, Soboslay PT. Onchocerca volvulus infection and serological prevalence, ocular onchocerciasis and parasite transmission in northern and central Togo after decades of Simulium damnosum s.l. vector control and mass drug administration of ivermectin. PLoS Negl Trop Dis 2018; 12:e0006312. [PMID: 29494606 PMCID: PMC5849363 DOI: 10.1371/journal.pntd.0006312] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 03/13/2018] [Accepted: 02/12/2018] [Indexed: 11/18/2022] Open
Abstract
Background Mass drug administration (MDA) of ivermectin has become the main intervention to control onchocerciasis or “river blindness”. In Togo, after many years of MDA, Onchocerca volvulus infection has declined dramatically, and elimination appears achievable, but in certain river basins the current situation remains unknown. We have conducted parasitological, serological, ophthalmological, and entomological assessments in northern and central Togo within the river basins of Ôti, Kéran and Mô. Methodology/Principal findings Examinations were completed in 1,455 participants from 11 onchocerciasis sentinel villages, and O. volvulus transmission by Simulium damnosum sensu lato (s.l.) was evaluated. In children (aged 1–10 years), the prevalence of microfilariae (Mf) was 2.3% and in adults it ranged from 5.1 to 13.3%. Positive IgG4 responses to O. volvulus adult (crude) worm antigen (OvAg) and the recombinant Ov16 antigen were in all-ages 48.7% and 34.4%, and 29.1% and 14.9% in children, respectively. In the river basin villages of Kéran, Mô and Ôti, the IgG4 seroprevalences to OvAg in children were 51.7%, 23.5% and 12.7%, respectively, and to the Ov16 antigen 33.3% (Kéran) and 5.2% (Ôti). Onchocerciasis ocular lesions (punctate keratitis, evolving iridocyclitis and chorioretinitis) were observed in children and young adults. O. volvulus-specific DNA (Ov150) was detected by poolscreen in vector samples collected from Tchitchira/Kéran(22.8%), Bouzalo/Mô(11.3%), Baghan/Mô(2.9%) and Pancerys/Ôti(4.9%); prevalences of O. volvulus infection in S. damnosum s.l. were, respectively, 1%, 0.5%, 0.1% and 0.2%. Conclusions/Significance In the northern and central river basins in Togo, interruption of O. volvulus transmission has not yet been attained. Patent O. volvulus infections, positive antibody responses, progressive ocular onchocerciasis were diagnosed, and parasite transmission by S. damnosum s.l. occurred close to the survey locations. Future interventions may require approaches selectively targeted to non-complying endemic populations, to the seasonality of parasite transmission and national onchocerciasis control programs should harmonize cross-border MDA as a coordinated intervention. Mass drug administration (MDA) with ivermectin has become the main tool in the efforts to control and eliminate onchocerciasis (“river blindness”). In some areas, and after many years of MDA, levels of Onchocerca volvulus infection (the causative parasite) have declined greatly, and elimination appears achievable. In certain river basins of northern and central Togo, the present epidemiological situation remains unknown. The guidelines of the World Health Organization recommend that before ivermectin MDA can be stopped, interruption of O. volvulus transmission must be demonstrated. To this end, parasitological, serological, ophthalmological, and entomological assessments were conducted in the Ôti, Kéran and Mô river basins. O. volvulus infections and positive antibody responses were found in children aged ≤10 years and adults. Progressive ocular onchocerciasis was diagnosed, and parasite transmission by Simulium damnosum s.l. (the disease vector) occurred close to the survey locations. Thus, O. volvulus transmission continues in northern and central Togo, and future interventions may require approaches selectively adapted to seasonal migration of non-complying endemic populations in and out of the river basins, as well as seasonal transmission by the vectors. National control programmes should harmonize cross-border MDA as a coordinated intervention.
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Affiliation(s)
- Kossi Komlan
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Patrick S. Vossberg
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Richard G. Gantin
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Tchalim Solim
- Centre Hospitalier Universitaire Campus, Université de Lomé, Lomé, Togo
| | - Francois Korbmacher
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Méba Banla
- Centre Hospitalier Universitaire Campus, Université de Lomé, Lomé, Togo
| | | | | | - Carsten Köhler
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Peter T. Soboslay
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
- * E-mail:
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Lustigman S, Makepeace BL, Klei TR, Babayan SA, Hotez P, Abraham D, Bottazzi ME. Onchocerca volvulus: The Road from Basic Biology to a Vaccine. Trends Parasitol 2017; 34:64-79. [PMID: 28958602 DOI: 10.1016/j.pt.2017.08.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/27/2017] [Accepted: 08/30/2017] [Indexed: 11/18/2022]
Abstract
Human onchocerciasis - commonly known as river blindness - is one of the most devastating yet neglected tropical diseases, leaving many millions in sub-Saharan Africa blind and/or with chronic disabilities. Attempts to eliminate onchocerciasis, primarily through the mass drug administration of ivermectin, remains challenging and has been heightened by the recent news that drug-resistant parasites are developing in some populations after years of drug treatment. Needed, and needed now, in the fight to eliminate onchocerciasis are new tools, such as preventive and therapeutic vaccines. This review summarizes the progress made to advance the onchocerciasis vaccine from the research laboratory into the clinic.
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Affiliation(s)
- Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F Kimball Research Institute, New York Blood Center, New York, NY, USA.
| | - Benjamin L Makepeace
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Thomas R Klei
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Simon A Babayan
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow and Moredun Research Institute, Glasgow, UK
| | - Peter Hotez
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Section of Pediatric Tropical Medicine, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - David Abraham
- Department of Microbiology and Immunology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Maria Elena Bottazzi
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Section of Pediatric Tropical Medicine, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
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Progress towards eliminating onchocerciasis in the WHO Region of the Americas: verification of elimination of transmission in Guatemala. Wkly Epidemiol Rec 2016; 91:501-5. [PMID: 27801556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Abstract
BACKGROUND Onchocerciasis, also known as "river blindness," is a parasitic disease that is caused by infection from the filarial nematode (roundworm), Onchocerca volvulus. Nematodes are transmitted from person to person by blackflies of the Simulium genus, which usually breed in fast flowing streams and rivers. The disease is the second leading infectious cause of blindness in endemic areas.Ivermectin (a microfilaricide) is widely distributed to endemic populations for prevention and treatment of onchocerciasis. Doxycycline, an antibiotic, targets Wolbachia organisms that are crucial to the survival of adult onchocerca (macrofilaricide). Combined treatment with both drugs is believed to cause direct microfilarial death by ivermectin and indirect macrofilarial death by doxycycline. Long-term reduction in the numbers of microfilaria in the skin and eyes and in the numbers of adult worms in the body has the potential to reduce the transmission and occurrence of onchocercal eye disease. OBJECTIVES The primary aim of this review was to assess the effectiveness of doxycycline plus ivermectin versus ivermectin alone for prevention and treatment of onchocerciasis. The secondary aim was to assess the effectiveness of doxycycline plus ivermectin versus ivermectin alone for prevention and treatment of onchocercal ocular lesions in communities co-endemic for onchocerciasis and Loa loa (loiasis) infection. SEARCH METHODS We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (Issue 7, 2015), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2015), EMBASE (January 1980 to July 2015), PubMed (1948 to July 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to July 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 1 July 2014), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 15 July 2015. SELECTION CRITERIA We included randomized controlled trials (RCTs) that had compared doxycycline plus ivermectin versus ivermectin alone. Participants with or without one or more characteristic signs of ocular onchocerciasis resided in communities where onchocerciasis was endemic. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trial eligibility and extracted data. We used standard methodological procedures as expected by Cochrane. MAIN RESULTS We identified three RCTs including a total of 466 participants with a diagnosis of onchocerciasis. All trials compared doxycycline plus ivermectin versus ivermectin alone. One study investigated improvement in visual impairment at six-month follow-up; the other two studies measured microfilarial loads in skin snips to assess sustained effects of treatment at follow-up of 21 months or longer. The studies were conducted at various centers across three countries (Cameroon, Ghana, and Liberia). We judged all studies to be at overall high risk of bias because of inadequate randomization and lack of masking (one study), missing data (two studies), and selective outcome reporting (three studies).Only one study measured visual outcomes. This study reported uncertainty about the difference in the proportion of participants with improvement in visual impairment at six-month follow-up for doxycycline plus ivermectin compared with ivermectin alone (risk ratio (RR) 1.06, 95% confidence interval (95% CI) 0.80 to 1.39; 240 participants; very low-quality evidence). No participant in either group showed improvement in optic atrophy, chorioretinitis, or sclerosing keratitis at six-month follow-up. More participants in the doxycycline plus ivermectin group than in the ivermectin alone group showed improvement in iridocyclitis (RR 1.24, 95% CI 0.69 to 2.22) and punctate keratitis (RR 1.43, 95% CI 1.02 to 2.00) at six-month follow-up; however, we graded these results as very low quality.Two studies reported that a six-week course of doxycycline may result in Wolbachia depletion and macrofilaricidal and sterilizing activities in female Onchocerca worms; however, no analysis was possible because data were missing and incomplete (graded evidence as very low quality). Adverse events were reported in 16 of 135 (12%) participants in one of these studies and included itching, headaches, body pains, and vertigo; no difference between treatment groups was reported for any adverse event. The second study reported that one (1.3%) participant in the doxycycline plus ivermectin group had bloody diarrhea after treatment was initiated. AUTHORS' CONCLUSIONS Available evidence on the effectiveness of doxycycline plus ivermectin compared with ivermectin alone in preventing and treating onchocerciasis is unclear. Limited evidence of very low quality from two studies indicates that a six-week course of doxycycline followed by ivermectin may result in more frequent macrofilaricidal and microfilaricidal activity and sterilization of female adult Onchocerca compared with ivermectin alone; however, effects on vision-related outcomes are uncertain. Future studies should consider the effectiveness of treatments in preventing visual acuity and visual field loss and their effects on anterior and posterior segment lesions, particularly chorioretinitis. These studies should report outcomes in a uniform and consistent manner at follow-up of three years or longer to allow detection of meaningful changes in vision-related outcomes.
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Affiliation(s)
- Ayokunle T Abegunde
- John H. Stroger, Jr. Hospital of Cook CountyDivision of Internal Medicine1900 W. Polk StreetChicagoILUSA60612
| | - Richard M Ahuja
- John H. Stroger, Jr. Hospital of Cook CountyDivision of Ophthalmology1900 W. Polk StreetChicagoILUSA60612
| | - Nkem J Okafor
- Kaplan Medical205 W. Randolph Street, Suite #200ChicagoILUSA60606
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Makepeace BL, Babayan SA, Lustigman S, Taylor DW. The case for vaccine development in the strategy to eradicate river blindness (onchocerciasis) from Africa. Expert Rev Vaccines 2015; 14:1163-5. [PMID: 26091691 DOI: 10.1586/14760584.2015.1059281] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Onchocerciasis or river blindness is a neglected parasitic disease causing severe dermatitis and visual impairment, predominantly in Africa. Historically, onchocerciasis control targeted vector breeding sites, but the current strategy relies on mass administration of a single drug, ivermectin. As programmatic goals shift from reducing public health impact to active elimination, sole reliance on ivermectin is threatened by contraindications in areas coendemic for loiasis, an inability to break transmission in some foci, and the emergence of drug resistance. Here, we argue that prophylactic and therapeutic vaccines would accelerate elimination efforts and safeguard the enormous strides made in onchocerciasis control. These vaccines could be based on one or more of three lead candidates identified by a newly formed transatlantic partnership, The Onchocerciasis Vaccine for Africa Initiative.
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Affiliation(s)
- Benjamin L Makepeace
- Institute of Infection & Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool L3 5RF, UK
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Kim YE, Remme JHF, Steinmann P, Stolk WA, Roungou JB, Tediosi F. Control, elimination, and eradication of river blindness: scenarios, timelines, and ivermectin treatment needs in Africa. PLoS Negl Trop Dis 2015; 9:e0003664. [PMID: 25860569 PMCID: PMC4393239 DOI: 10.1371/journal.pntd.0003664] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/02/2015] [Indexed: 11/18/2022] Open
Abstract
River blindness (onchocerciasis) causes severe itching, skin lesions, and vision impairment including blindness. More than 99% of all current cases are found in sub-Saharan Africa. Fortunately, vector control and community-directed treatment with ivermectin have significantly reduced morbidity. Studies in Mali and Senegal proved the feasibility of elimination with ivermectin administration. The treatment goal is shifting from control to elimination in endemic African regions. Given limited resources, national and global policymakers need a rigorous analysis comparing investment options. For this, we developed scenarios for alternative treatment goals and compared treatment timelines and drug needs between the scenarios. Control, elimination, and eradication scenarios were developed with reference to current standard practices, large-scale studies, and historical data. For each scenario, the timeline when treatment is expected to stop at country level was predicted using a dynamical transmission model, and ivermectin treatment needs were predicted based on population in endemic areas, treatment coverage data, and the frequency of community-directed treatment. The control scenario requires community-directed treatment with ivermectin beyond 2045 with around 2.63 billion treatments over 2013–2045; the elimination scenario, until 2028 in areas where feasible, but beyond 2045 in countries with operational challenges, around 1.15 billion treatments; and the eradication scenario, lasting until 2040, around 1.30 billion treatments. The eradication scenario is the most favorable in terms of the timeline of the intervention phase and treatment needs. For its realization, strong health systems and political will are required to overcome epidemiological and political challenges. River blindness (onchocerciasis) is transmitted by blackflies and causes severe itching, skin lesions, and vision impairment including blindness. More than 99% of all current cases are found in sub-Saharan Africa where the disease has historically hindered socioeconomic development in endemic areas. The treatment goal is shifting from control to elimination in Africa as morbidity has significantly decreased through vector control and community-directed treatment with ivermectin. Studies in Mali and Senegal proved that elimination is feasible with ivermectin administration. Given limited resources, national and global policymakers need a rigorous analysis of investment options from epidemiological, economic, and societal aspects. For this, we developed control, elimination, and eradication scenarios and compared treatment timelines and drug needs over the next 30 years. We found that the elimination and eradication scenarios would require a shorter treatment phase and a smaller amount of ivermectin than the control scenario, mainly because community-directed treatment with ivermectin could be ended earlier thanks to regular active surveillance.
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Affiliation(s)
- Young Eun Kim
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | | | - Peter Steinmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Wilma A. Stolk
- Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Fabrizio Tediosi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Meeting of the International Task Force for Disease Eradication, January 2014. Wkly Epidemiol Rec 2014; 89:153-60. [PMID: 24754045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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African Programme for Onchocerciasis Control: meeting of National Onchocerciasis Task Forces, September 2013. Wkly Epidemiol Rec 2013; 88:533-44. [PMID: 24367839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Progress towards eliminating onchocerciasis in the WHO Region of the Americas: verification by WHO of elimination of transmission in Colombia. Wkly Epidemiol Rec 2013; 88:381-5. [PMID: 24052954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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Affiliation(s)
- S Resnikoff
- Prevention of Blindness and Deafness, Chronic Diseases Prevention and Management, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
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Centers for Disease Control and Prevention (CDC). Progress toward elimination of onchocerciasis in the Americas - 1993-2012. MMWR Morb Mortal Wkly Rep 2013; 62:405-8. [PMID: 23698606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Onchocerciasis (river blindness) is caused by the parasitic worm Onchocerca volvulus, transmitted to humans by the bite of infected black flies of the genus Simulium, and is characterized by chronic skin disease, severe itching, and eye lesions that can progress to complete blindness. Currently, among approximately 123 million persons at risk for infection in 38 endemic countries, at least 25.7 million are infected, and 1 million are blinded or have severe visual impairment. Periodic, communitywide mass drug administration (MDA) with ivermectin (Mectizan, Merck) prevents eye and skin disease and might interrupt transmission of the infection, depending on the coverage, duration, and frequency of MDA. The Onchocerciasis Elimination Program for the Americas (OEPA) was launched in response to a 1991 resolution of the Pan American Health Organization (PAHO) calling for the elimination of onchocerciasis from the Americas. By the end of 2012, transmission of the infection, judged by surveys following World Health Organization (WHO) guidelines, had been interrupted or eliminated in four of the six endemic countries in the WHO Americas Region. Thus, in 2013, only 4% (23,378) of the 560,911 persons originally at risk in the Americas will be under ivermectin MDA. Active transmission currently is limited to two foci among Yanomami indigenes in adjacent border areas of Venezuela and Brazil.
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African Programme for Onchocerciasis Control: meeting of National Onchocerciasis Task Forces, September 2012. Wkly Epidemiol Rec 2012; 87:494-502. [PMID: 23311005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Affiliation(s)
- Pascale Allotey
- Global Public Health, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, Bandar Sunway, Selangor DE 46150, Malaysia.
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Meredith SEO, Cross C, Amazigo UV. Empowering communities in combating river blindness and the role of NGOs: case studies from Cameroon, Mali, Nigeria, and Uganda. Health Res Policy Syst 2012; 10:16. [PMID: 22574885 PMCID: PMC3453498 DOI: 10.1186/1478-4505-10-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 05/10/2012] [Indexed: 11/24/2022] Open
Abstract
The control of onchocerciasis is not only a major success story in global health, but also one of the best examples of the power of public-private partnership at the international level as well as at the national level. The onchocerciasis story is also a leading example of the contribution of a group of called Non-Governmental Development Organizations (NGDO) to operational research which resulted in important changes in treatment strategies and policies.The four case studies presented here illustrate some key contributions the NGDOs made to the development of "community directed treatment with ivermectin" -CDTI, in Africa, which became the approved methodology within the African Programme for Onchocerciasis Control (APOC). The partnership between the international, multilateral, government institutions and the NGDO Coordination Group was the backbone of the APOC programme's structure and facilitated progress and scale-up of treatment programmes. Contributions included piloting community-based methodology in Mali and Nigeria; research, collaboration and coordination on treatment strategies and policies, coalition building, capacity building of national health workforce and advocacy at the national and international level. While the Onchocerciasis Control Programme (OCP) and APOC provided leadership, the NGDOs working with the national health authorities played a major role in advocacy evolving the community methodology which led to achieving and maintaining- treatments with ivermectin for at least 20 years and strengthening community health systems.
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Katabarwa MN, Eyamba A, Nwane P, Enyong P, Yaya S, Baldiagaï J, Madi TK, Yougouda A, Andze GO, Richards FO. Seventeen years of annual distribution of ivermectin has not interrupted onchocerciasis transmission in North Region, Cameroon. Am J Trop Med Hyg 2011; 85:1041-9. [PMID: 22144441 PMCID: PMC3225149 DOI: 10.4269/ajtmh.2011.11-0333] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 08/02/2011] [Indexed: 11/07/2022] Open
Abstract
We studied onchocerciasis transmission and impact on ocular morbidity in three health districts in North Region, Cameroon, where annual mass ivermectin treatment has been provided for 12-17 years. The studies, which took place from 2008 to 2010, consisted of skin snips for microfilariae (mf), palpation examinations for nodules, slit lamp examinations for mf in the eye, and Simulium vector dissections for larval infection rates. Adults had mf and nodule rates of 4.8% and 13.5%, respectively, and 5.5% had mf in the anterior chamber of the eye. Strong evidence of ongoing transmission was found in one health district, where despite 17 years of annual treatments, the annual transmission potential was 543 L3/person per year; additionally, children under 10 years of age had a 2.6% mf prevalence. Halting ivermectin treatments in North Cameroon now might risk recrudescence of transmission and ocular disease.
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African Programme for Onchocerciasis Control: meeting of National Task Forces, September 2011. Wkly Epidemiol Rec 2011; 86:541-9. [PMID: 22128386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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InterAmerican Conference on Onchocerciasis, 2010: progress towards eliminating river blindness in the WHO Region of the Americas. Wkly Epidemiol Rec 2011; 86:417-23. [PMID: 21969940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Babalola OE, Ogbuagu FK, Maegga BT, Braide EI, Magimbi C, Zoure H, Yameogo L, Seketeh A. African programme for Onchoceriasis control: ophthalmological findings in Bushenyi, Uganda. West Afr J Med 2011; 30:104-109. [PMID: 21984457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND The overall prevalence of blindness from Onchoceriasis in Bushenyi is relatively low, most of which is to be found in the elderly. Onchoceriasis is a major health problem in Africa. The Community-Directed treatment with invermectin is a control strategy to address the problem, but baseline data are generally lacking in several countries. OBJECTIVE To describe baseline ophthalmological data in order to assess the impact of Community-Directed with Ivermectin (CDTI) in Uganda. METHODS The study site was in Bushenyi, Western Uganda. In a cross-sectional study, 367 persons aged 10 years or older from seven selected villages received eye examination using a standardised protocol and Wu-Jones Motion Sensitivity Testing (MSST). Besides MSST, other information sought included visual acuity, slit lamp examination, testicular opacities and intraocular presence. RESULTS Of the 367 subjects, 219(57.2%) were males. Subjects less than 25 years of age were 104(28.3). The prevalence of blindness were 1.9% while 4.1% was visually impaired by acuity criteria alone. A further 9.1% had moderate visual field loss while 2.8% had severe field loss. There was no case of anterior chamber microfilaria but dead microfilariae were seen in two cases. Punctate keratitis was present in 1.8% with sclerosing keratitis was twice as common at 3.8%. Optic atrophy was also relatively common at 12.4%, while chorioretinitis was present in 3.3%. CONCLUSION There was an apparent paucity of acute onchocerciasis-related lesions but a significant presence of irreversible onchocerciasis-related lesions. The most significant problem requiring intervention would appear to be cataract.
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Report from the 2009 Inter-American Conference on Onchocerciasis: progress towards eliminating river blindness in the Region of the Americas. Wkly Epidemiol Rec 2010; 85:321-6. [PMID: 20707042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Onchocerciasis (river blindness). Report from the eighteenth InterAmerican Conference on Onchocerciasis, November 2008. Wkly Epidemiol Rec 2009; 84:385-9. [PMID: 19764129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Onchocerciasis: elimination is feasible. Wkly Epidemiol Rec 2009; 84:382-3. [PMID: 19764128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Abstract
INTRODUCTION Within the mesoendemic onchocerciasis belt of Kaduna State, Northern Nigeria, there were other causes of ocular morbidity as well. We investigated the contribution of trachoma. METHODS A total of 6831 individuals were examined for eye disease, including signs of trachoma. RESULTS The overall prevalence of trachoma was 4.5% (577 eyes of 310 individuals), making it the second most common cause (1 in 5) of ocular morbidity after cataracts. Of the 577 eyes, 405 (70.2%) had cicatrizing disease while the rest had active disease. Overall, the prevalence of TF was 1.1% (1.3% in those < 10 years of age), TI 0.2%, TS 3%, CO 0.5% and TT 1.1% (4.3% and 3.5% in subjects aged > 55 and > 40 years, respectively). The prevalence of trachoma increased with age. The overall prevalence of blindness in the whole population was 2.7%. Trachoma accounted for 11% of this. On the other hand, onchocerciasis accounted for 3.1% of the overall ocular morbidity (less than trachoma) and 39% of the blindness. CONCLUSIONS There appears to be a clear need to retrain middle cadre ivermectin workers in trachoma rapid assessment and SAFE strategy intervention methods in order to further impact blindness prevention in these 'onchocerciasis-endemic' zones.
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Babalola OE, Maegga B, Katenga S, Ogbuagu FK, Umeh RE, Seketeli E, Braide E. APOC impact assessment studies: baseline ophthalmological findings in Morogoro, Tanzania. Afr J Med Med Sci 2008; 37:327-332. [PMID: 19301709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The goal of the African Programme for Onchocerciasis Control (APOC) is to eliminate Onchocerciasis as a disease of public Health significance and an important constraint to socio-economic development in the 19 none OCP (Onchocerciasis Control Project) countries covered through Community-Directed Treatment with Ivermectin, CDTI. In 1998, impact assessment studies were carried out in Morogoro, Tanzania during which baseline ophthalmological parameters were established. The hypothesis being tested is that CDTI will prevent or delay progression of onchocercal eye lesions and blindness. A total of 425 subjects aged 10 years or more from 14 villages within Bwakira district ofMorogoro region in Tanzania were examined for Snellen visual acuity, ocular microfilaria, lens opacities, uveitis and posterior segment disease especially chorioretinitis and optic nerve disease. Motion Sensitivity Screening Test (MSST) was carried out as well. Microfilaria was present in the anterior chamber of nearly half (49.2%) of all subjects examined. Prevalence of blindness was extremely high at 15.2%. Onchocercal lesions were responsible for blindness in 41.5% of these, followed by cataracts (27.7%), glaucoma (10.8%) and trachoma (6.2%). The main pathway to onchocercal blindness in this population was anterior uveitis with or without secondary cataracts. There is an urgent need to get CDTI underway and institute other horizontal primary eye care measures, especially cataract backlog reduction, in order to reduce the excessive burden of avoidable blindness in this community.
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Report from the Inter-American Conference on Onchocerciasis, November 2007. Wkly Epidemiol Rec 2008; 83:256-60. [PMID: 18637266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Hodgkin C, Molyneux DH, Abiose A, Philippon B, Reich MR, Remme JH, Thylefors B, Traore M, Grepin K. The future of onchocerciasis control in Africa. PLoS Negl Trop Dis 2007; 1:e74. [PMID: 17989787 PMCID: PMC2041822 DOI: 10.1371/journal.pntd.0000074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
| | - David H. Molyneux
- Lymphatic Filariasis Support Centre, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
| | | | | | - Michael R. Reich
- Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - J. Hans Remme
- Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Bjorn Thylefors
- Mectizan Donation Program, Task Force for Child Survival and Development, Atlanta, Georgia, United States of America
| | - Mamadou Traore
- Institut National de Recherche en Santé Publique, Bamako, Mali
| | - Karen Grepin
- Harvard University, Boston, Massachusetts, United States of America
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Onchocerciasis (river blindness). Report from the sixteenth InterAmerican Conference on Onchocerciasis, Antigua Guatemala, Guatemala. Wkly Epidemiol Rec 2007; 82:314-6. [PMID: 17763565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
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Affiliation(s)
- Peter J Hotez
- Sabin Vaccine Institute and Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC 20037, USA.
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Osei-Atweneboana MY, Eng JK, Boakye DA, Gyapong JO, Prichard RK. Prevalence and intensity of Onchocerca volvulus infection and efficacy of ivermectin in endemic communities in Ghana: a two-phase epidemiological study. Lancet 2007; 369:2021-2029. [PMID: 17574093 DOI: 10.1016/s0140-6736(07)60942-8] [Citation(s) in RCA: 298] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Ivermectin has been used for onchocerciasis control since 1987. Because of the long-term use of this drug and the development of resistance in other nematodes, we have assessed Onchocerca volvulus burdens, effectiveness of ivermectin as a microfilaricide, and its effect on adult female worm reproduction. METHODS For the first phase of the study, 2501 individuals in Ghana, from 19 endemic communities who had received six to 18 annual rounds of ivermectin and one ivermectin naive community, were assessed for microfilarial loads 7 days before the 2004 yearly ivermectin treatment, by means of skin snips, and 30 days after treatment to assess the ivermectin microfilaricidal action. For the second phase, skin snips were taken from 342 individuals from ten communities, who were microfilaria positive at pretreatment assessment, on days 90 and 180 after treatment, to identify the effects of ivermectin on female worm fertility, assessed by microfilaria repopulation. FINDINGS 487 (19%) of the 2501 participants were microfilaria positive. The microfilaria prevalence and community microfilarial load in treated communities ranged from 2.2% to 51.8%, and 0.06 microfilariae per snip to 2.85 microfilariae per snip, respectively. Despite treatment, the prevalence rate doubled between 2000 and 2005 in two communities. Microfilaria assessment 30 days after ivermectin treatment showed 100% clearance of microfilaria in more than 99% of people. At day 90 after treatment, four of ten communities had significant microfilaria repopulation, from 7.1% to 21.1% of pretreatment counts, rising to 53.9% by day 180. INTERPRETATION Ivermectin remains a potent microfilaricide. However, our results suggest that resistant adult parasite populations, which are not responding as expected to ivermectin, are emerging. A high rate of repopulation of skin with microfilariae will allow parasite transmission, possibly with ivermectin-resistant O volvulus, which could eventually lead to recrudescence of the disease.
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Affiliation(s)
- Mike Y Osei-Atweneboana
- Institute of Parasitology, McGill University, Canada; Council for Scientific and Industrial Research, Ghana
| | | | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - John O Gyapong
- Health Research Unit, Ghana Health Services, Ghana; Ochocerciasis Control Programme of Ghana, Ghana
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Abstract
The success of the Onchocerciasis Control Programme is undeniable and exemplary, say the authors, but it is too early to claim victory against river blindness.
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Affiliation(s)
- María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, Imperial College of Science, Technology and Medicine, London, United Kingdom.
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Onchocerciasis (river blindness). Report from the fifteenth InterAmerican Conference on Onchocerciasis, Caracas, Venezuela. Wkly Epidemiol Rec 2006; 81:293-6. [PMID: 16874924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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Katholi CR, Unnasch TR. Important experimental parameters for determining infection rates in arthropod vectors using pool screening approaches. Am J Trop Med Hyg 2006; 74:779-85. [PMID: 16687680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023] Open
Abstract
Measuring transmission of a vector-borne infection is essential to understanding infection dynamics. When infection prevalence in the vector population is low, transmission is often measured by pool screening (also referred to as group testing). Several investigators have developed statistical methods to recover infection prevalence estimates from pool screen data. These are based on models that contain certain assumptions, and a pool screening approach must be designed to take these into account if accurate estimates of infection prevalence are to be obtained. Here we describe these assumptions and discuss appropriate sampling protocols. The sources of error inherent in pool screening are described, and we show that, under most conditions in which one would want to use group testing, most of the error results from sampling and not the pooling process. Issues involved in developing a sampling protocol, including the total number of insects to be screened and optimal pool size, are explored. The meaning of confidence intervals associated with prevalence estimates and the appropriate interpretation of these intervals are discussed.
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Affiliation(s)
- Charles R Katholi
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama 35294-0022, USA.
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Abstract
The donation of ivermectin by Merck and Co. Inc. has led to one of the most effective private-public partnerships controlling a disease of major public health importance particularly in Africa. The up scaling of ivermectin distribution during the last 15 years has been remarkable with almost 40 million people treated in 2003, many already on their regular annual dose. The tools that have been developed particularly by the APOC programme have been instrumental in this increase. However, ivermectin is a microfilaricide and does not kill the adult worms. Distribution will be needed for at least 25 years and latest estimates indicate that 90 million people need annual treatment if onchocerciasis is to be eliminated as a public health problem. In spite of this incredible progress it is difficult to see how the programme will be sustained, especially after the closure of APOC in 2010. A macrofilaricide destroying adult worms and safe for mass distribution would solve the problem of onchocerciasis.
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Stingl P. [Onchocerciasis]. MMW Fortschr Med 2004; 146:44-5. [PMID: 15581105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Onchocerciasis, which is caused by filarial nematodes, affects roughly 18 million people in tropical Africa and is a major cause of morbidity, with a serious sociomedical impact. Although the present onchocerciasis control strategy comprising antifilarial chemotherapy and vector control is successful, it is associated with logistic problems due to the prolonged treatment duration. Furthermore, fears of drug resistance are on the increase. New approaches involving the use of antibiotics aimed at endobacteria living in symbiosis with filariae appear promising. Recent trials with tetracycline indicate a significant impact on worm viability.
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Little MP, Basanez MG, Breitling LP, Boatin BA, Alley ES. Incidence of blindness during the Onchocerciasis control programme in western Africa, 1971-2002. J Infect Dis 2004; 189:1932-41. [PMID: 15122532 DOI: 10.1086/383326] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Accepted: 10/02/2003] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Infection with Onchocerca volvulus is associated with the prevalence of severe visual impairment and blindness. However, longitudinal studies of the incidence of blindness caused by onchocerciasis are scarce. METHODS The relationship, at the individual level, between infection with O. volvulus microfilariae and bilateral blindness was examined, by use of data collected, during the Onchocerciasis Control Programme in western Africa (OCP), from 2315 villages in 11 countries. The data were analyzed by Poisson maximum-likelihood techniques with adjustment for overdispersion. RESULTS A total of 297,756 persons were eligible for follow-up in the cohort, and, during 1971-2001, these persons accumulated 367,788 person-years of follow-up without blindness. A total of 673 bilateral cases of blindness occurred during this period; 29.7% were caused by onchocerciasis. After ivermectin therapy was introduced (during 1988-2001), only 19.6% of cases were caused by onchocerciasis. The incidence of blindness was significantly and positively associated with increasing microfilarial burden (P<.001). Overall, female subjects had an ~40% lower risk of becoming blind than did male subjects (P<.001). After an initially high incidence of blindness at the beginning of the OCP, the rate of blindness from causes other than onchocerciasis remained approximately constant during follow-up. CONCLUSIONS We demonstrate, in a comprehensive data set and in both sexes, a direct relationship between microfilarial load and the incidence of blindness.
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Affiliation(s)
- Mark P Little
- Department of Epidemiology and Public Health, Imperial College London, Faculty of Medicine, St. Mary's Campus, London, United Kingdom.
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