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Khainza AT, Soita D, Okia D, Okello F, Matovu JKB, Lubaale Y, Byamukama E, Okibure A, Alunyo JP, Nantale R, Wanume B, Ogutu D, Mukunya D, Olupot-Olupot P. Community Involvement in Onchocerciasis Post-elimination Surveillance in Bududa District, Eastern Uganda: A cross-sectional study. PLoS Negl Trop Dis 2024; 18:e0012270. [PMID: 39012847 PMCID: PMC11251607 DOI: 10.1371/journal.pntd.0012270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 06/04/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND Globally, there are an estimated 20.9 million cases of onchocerciasis, with Africa bearing the greatest burden. The World Health Organization (WHO) has targeted the disease for elimination by 2030. As of August 2023, there were 15 foci in 37/48 (76%) districts and one city in Uganda that had reached the elimination phase. However, there is a paucity of data on community involvement in post-elimination surveillance (PES) activities. The communities in the post-elimination phase are expected to maintain surveillance, provide health education, refer cases for treatment, and participate in surveillance. However, it is not clear whether this is being done. In this study, we assessed the feasibility of community involvement in post-elimination surveillance activities in Bududa District, Eastern Uganda, to draw key generalisable lessons for similar settings. METHODS This was a cross-sectional study employing rigorous mixed methods of data collection. We used a semi-structured questionnaire to collect quantitative data on randomly sampled study participants in two sub-countries in the district. Community involvement in post-elimination surveillance (PES) was our dependent variable, measured using Yes or No questions, and our independent variables were measured on different scales. Computations of proportions and associations were done using Stata 15 software. Conversely, qualitative data were collected via focus group discussions (FGDs) for community participants and key informant interviews (KIIs) for local leaders. For the qualitative component, we had 2 FGDs, each consisting of 8 gender-balanced participants per group and 8 KIIs. Qualitative data analyses were done using a robust thematic framework approach, ensuring the reliability and validity of our findings. RESULTS A total of 422 participants with a mean age of 51.4 years (SD = 15.8) participated in the study. Community involvement in post-elimination surveillance was low (14%). Factors associated with involvements were district support [Adjusted odd ratio AOR 14, 95 CI = (2.5, 81.7)], seeing black flies in the environment in a week preceding the survey [AOR 8, 95% CI = (1.5, 42.5)], in one month [AOR 3.8, 95% CI = (1.1, 13.2)], and being a community volunteer in the Ivermectin treatment program [AOR 4.3, 95% CI = (1.03, 17.9)]. Lack of funding, poor motivation, poor program sustainability planning, and a lack of drugs at health facilities were key challenges affecting community involvement in post-elimination surveillance. CONCLUSION Community involvement in onchocerciasis post-elimination surveillance activities in Bududa District in Eastern Uganda was low but could be improved by increased district support, funding, community motivation and sensitisation.
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Affiliation(s)
- Annet Tabitha Khainza
- Department of Community and Public Health, Busitema University, Mbale, Uganda
- The Carter Center, Kampala, Uganda
| | - David Soita
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - David Okia
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - Francis Okello
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - Joseph KB Matovu
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - Yovani Lubaale
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | | | - Ambrose Okibure
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | | | - Ritah Nantale
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - Benon Wanume
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | | | - David Mukunya
- Department of Community and Public Health, Busitema University, Mbale, Uganda
| | - Peter Olupot-Olupot
- Department of Community and Public Health, Busitema University, Mbale, Uganda
- Department of Research, Mbale Clinical Research Institute, Mbale, Uganda
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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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3
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Jacob B, Michael E, Unnasch TR. Community-Directed Vector Control to Accelerate Onchocerciasis Elimination. Pathogens 2024; 13:268. [PMID: 38535611 PMCID: PMC10975871 DOI: 10.3390/pathogens13030268] [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: 02/20/2024] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 04/01/2024] Open
Abstract
Onchocerciasis, or river blindness, has historically been one of the most important causes of blindness worldwide, and a major cause of socio-economic disruption, particularly in sub-Saharan Africa. Its importance as a cause of morbidity and an impediment to economic development in some of the poorest countries in the world motivated the international community to implement several programs to control or eliminate this scourge. Initially, these involved reducing transmission of the causative agent Onchocerca volvulus through controlling the vector population. When ivermectin was found to be a very effective drug for treating onchocerciasis, the strategy shifted to mass drug administration (MDA) of endemic communities. In some countries, both vector control and ivermectin MDA have been used together. However, traditional vector control methods involve treating rivers in which the black fly vectors breed with insecticides, a process which is expensive, requires trained personnel to administer, and can be ecologically harmful. In this review, we discuss recent research into alternatives to riverine insecticide treatment, which are inexpensive, ecologically less harmful, and can be implemented by the affected communities themselves. These can dramatically reduce vector densities and, when combined with ivermectin MDA, can accelerate the time to elimination when compared to MDA alone.
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Affiliation(s)
| | | | - Thomas R. Unnasch
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, FL 33612, USA; (B.J.); (E.M.)
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4
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Jacob B, Loum D, Munu D, Lakwo T, Byamukama E, Habomugisha P, Cupp EW, Unnasch TR. Optimization of Slash and Clear Community-Directed Control of Simulium damnosum Sensu Stricto in Northern Uganda. Am J Trop Med Hyg 2021; 104:1394-1403. [PMID: 33432900 DOI: 10.4269/ajtmh.20-1104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/10/2020] [Indexed: 11/07/2022] Open
Abstract
Onchocerciasis, caused by infection with Onchocerca volvulus, has been targeted for elimination by 2030. Currently, onchocerciasis elimination programs rely primarily on mass distribution of ivermectin. However, ivermectin alone may not be sufficient to achieve elimination in some circumstances, and additional tools may be needed. Vector control has been used as a tool to control onchocerciasis, but vector control using insecticides is expensive and ecologically detrimental. Community-directed removal of the trailing vegetation blackfly larval attachment sites (slash and clear) has been shown to dramatically reduce vector biting densities. Here, we report studies to optimize the slash and clear process. Conducting slash and clear interventions at Simulium damnosum sensu stricto breeding sites located within 2 km of afflicted communities resulted in a 95% reduction in vector biting. Extending slash and clear further than 2 km resulted in no further decrease. A single intervention conducted at the first half of the rainy season resulted in a 97% reduction in biting rate, whereas an intervention conducted at the end of the rainy season resulted in a 94% reduction. Vector numbers in any of the intervention villages did not fully recover by the start of the following rainy season. These results suggest that slash and clear may offer an inexpensive and effective way to augment ivermectin distribution in the effort to eliminate onchocerciasis in Africa.
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Affiliation(s)
- Benjamin Jacob
- College of Public Health, University of South Florida, Tampa, Florida
| | - Denis Loum
- Nwoya District Local Government, Nwoya, Uganda
| | - Denis Munu
- The Carter Center, Uganda Office, Kampala, Uganda
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | - Eddie W Cupp
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida
| | - Thomas R Unnasch
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida
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5
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Katabarwa MN, Habomugisha P, Khainza A, Oguttu D, Byamukama E, Katamanywa J, Isingooma T, Bwenume F, Nahabwe C, Ngabirano M, Akampurira P, Bernard L, Unnasch TR, Richards F. Elimination of Simulium neavei-Transmitted Onchocerciasis in Wambabya-Rwamarongo Focus of Western Uganda. Am J Trop Med Hyg 2020; 103:1135-1142. [PMID: 32588807 PMCID: PMC7470550 DOI: 10.4269/ajtmh.20-0195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Wambabya–Rwamarongo onchocerciasis focus is one of the eight foci Uganda verified using the WHO verification guidelines. The approach for elimination was twice yearly treatment with ivermectin for every round, treating at least 90% of all the eligible population. This was in combination with vector elimination using Abate® (BASF SE, Limburgerhof, Germany) since elimination nationwide policy was launched. From 2008 to 2013, the program distributed ivermectin with a mean treatment coverage of the ultimate treatment goal (UTG) or eligible population of 91.2%, with a range of 85–96%. In 2009, vector elimination based on ground larviciding had a dramatic impact on the Simulium vectors, as the last fly was observed in October 2009. No more Simulium vectors were observed during a period of at least 7 years, including the 3-year posttreatment surveillance (PTS) until the focus was reclassified as eliminated in August 2017. During the PTS period, none of the 10,578 trapped crabs were found infested with the aquatic stages of the vector. The last infested crab was observed in March 2010, and for at least 7 years, no infested crabs were observed. Serological surveys showed that of 2,978 young children examined in 2013, only one was OV16 positive (0.0%; 95% CI: 0–0.21). In 2017, after the PTS period, all 3,079 young children examined were negative for OV16 (95% CI: 0–0.16). Therefore, entomological and serological results provided evidence that resulted in the reclassification of Wambabya–Rwamarongo focus from “transmission interrupted” to “transmission eliminated” with no possibility of recrudescence.
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Affiliation(s)
| | | | | | - David Oguttu
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | | | | | | | | | - Paul Akampurira
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Thomas R Unnasch
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, Florida
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6
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Lakwo T, Oguttu D, Ukety T, Post R, Bakajika D. Onchocerciasis Elimination: Progress and Challenges. Res Rep Trop Med 2020; 11:81-95. [PMID: 33117052 PMCID: PMC7548320 DOI: 10.2147/rrtm.s224364] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/16/2020] [Indexed: 01/08/2023] Open
Abstract
Onchocerciasis is a parasitic infection caused by the filarial nematode Onchocerca volvulus and transmitted through the bites of black flies of the genus Similium that breed in rivers and streams. The impact of mass treatment with ivermectin and supplemented by vector control in some countries has changed the global scene of onchocerciasis. There has been reported progress made in elimination of onchocerciasis in central and southern American countries and in some localities in Africa. The target for elimination in the Americas has been set at 2022 while for 12 countries in Africa this is expected in 2030. This review was conducted to examine the current status of onchocerciasis elimination at the global level and report on progress made. Literature searches were made through PubMed, articles in English or English abstracts, reports and any other relevant articles related to the subject. The global burden of onchocerciasis is progressively reducing and is no longer a public health problem in some regions. However, programs are challenged with a range of issues: cross-border transmission, diagnostic tools, Loa loa co-endemicity, limited workforce in entomology and maintaining enthusiasm among community drug distributors. More concerted effort using appropriate tools is required to overcome the challenges.
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Affiliation(s)
- Thomson Lakwo
- Neglected Tropical Disease Control Program, Vector Control Division, Ministry of Health, Kampala, Uganda
| | - David Oguttu
- Neglected Tropical Disease Control Program, Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Tony Ukety
- Centre de Recherche pour les Maladies Tropicales, Rethy, Ituri Province, The Democratic Republic of the Congo
| | - Rory Post
- Disease Control Department, London School of Hygiene & Tropical Medicine, London, UK.,School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Didier Bakajika
- Expanded Special Project for Elimination of Neglected Tropical Diseases, WHO Regional Office for Africa, Brazzaville, Congo
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7
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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] [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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8
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Cama VA, McDonald C, Arcury-Quandt A, Eberhard M, Jenks MH, Smith J, Feleke SM, Abanyie F, Thomson L, Wiegand RE, Cantey PT. Evaluation of an OV-16 IgG4 Enzyme-Linked Immunosorbent Assay in Humans and Its Application to Determine the Dynamics of Antibody Responses in a Non-Human Primate Model of Onchocerca volvulus Infection. Am J Trop Med Hyg 2019; 99:1041-1048. [PMID: 30062989 DOI: 10.4269/ajtmh.18-0132] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Onchocerciasis is a neglected parasitic disease targeted for elimination. Current World Health Organization guidelines for elimination include monitoring antibody responses to the recombinant Onchocerca volvulus antigen OV-16 in children to demonstrate the absence of transmission. We report the performance characteristics of a modified OV-16 enzyme-linked immunosorbent assay (ELISA) and describe anti-OV-16 responses in serum samples from laboratory-inoculated nonhuman primates (NHPs) in relation to microfilariae (mf) in skin snip biopsies. This OV-16 IgG4 ELISA had sensitivity and specificity of 88.2% and 99.7%, respectively, as determined by receiver operator characteristic analysis using a serum panel of 110 positive and 287 negative samples from people infected with other filariae or other parasitic infections. Anti-OV-16 responses in inoculated NHP (N = 9) were evaluated at quarterly intervals for IgM and the four IgG subclasses. Enzyme-linked immunosorbent assay results showed a well-defined IgG4 reactivity pattern and moderate IgG1 antibody responses. Meanwhile, the reactivity by IgG2, IgG3, or IgM did not show a clear pattern. Temporal evolution of IgG4 reactivity was evaluated through monthly testing, showing that NHPs developed anti-OV-16 IgG4 on average at 15 months postinoculation (range: 10-18 months). The average time to detectable mf was also 15 months (range: 11-25). The OV-16 ELISA used in this study was robust and allowed the detection of IgG4 responses, which were observed only among animals with detectable mf (N = 5), four of which showed declines in antibody responses once mf cleared. These findings also confirmed that the most informative antibody subclass responses to OV-16 are IgG4.
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Affiliation(s)
- Vitaliano A Cama
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Circe McDonald
- IHRC Inc., Atlanta, Georgia.,Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alice Arcury-Quandt
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Mark Eberhard
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - M Harley Jenks
- IHRC Inc., Atlanta, Georgia.,Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jared Smith
- IHRC Inc., Atlanta, Georgia.,Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Francisca Abanyie
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Lakwo Thomson
- Vector Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Paul T Cantey
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
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9
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Cantey PT, Roy SL, Boakye D, Mwingira U, Ottesen EA, Hopkins AD, Sodahlon YK. Transitioning from river blindness control to elimination: steps toward stopping treatment. Int Health 2019; 10:i7-i13. [PMID: 29471338 PMCID: PMC5881257 DOI: 10.1093/inthealth/ihx049] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/31/2017] [Indexed: 11/18/2022] Open
Abstract
The transition from onchocerciasis control to elimination requires country programmes to rethink their approach to a variety of activities as they move from addressing morbidity to addressing transmission of the parasite. Although the 2016 WHO guidelines provide extensive recommendations, it was beyond the scope of the document to provide guidance on all aspects of the transition. This paper will discuss some of the important issues that programmes are grappling with as they transition to elimination and provide some potential approaches that programmes can use to address them. Although there are some data to support some aspects of the suggested approaches, operational research will be needed to generate data to support these approaches further and to determine how programmes could best tailor them to their own unique epidemiological challenges. Good communication between the national programmes and the broader global programme will facilitate the clear articulation of programmatic challenges and the development of the evidence to support programme decision-making.
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Affiliation(s)
- Paul T Cantey
- Department of Neglected Tropical Diseases, World Health Organization, Geneva 1211, Switzerland
| | - Sharon L Roy
- Division of Parasitic Diseases and Malaria, U.S. Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Daniel Boakye
- Parasitology Department, Noguchi Memorial Institute for Medical Research, Accra, LG581, Ghana
| | - Upendo Mwingira
- Neglected Tropical Diseases Control Programme, Ministry of Health, Community Development, Gender, Elderly and Children, Dar es Salaam 11478, Tanzania.,National Institute for Medical Research, Dar es Salaam 11101, Tanzania
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10
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Katabarwa MN, Lakwo T, Habomugisha P, Unnasch TR, Garms R, Hudson-Davis L, Byamukama E, Khainza A, Ngorok J, Tukahebwa E, Richards FO. After 70 years of fighting an age-old scourge, onchocerciasis in Uganda, the end is in sight. Int Health 2019; 10:i79-i88. [PMID: 29471335 DOI: 10.1093/inthealth/ihx044] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/26/2017] [Indexed: 11/13/2022] Open
Abstract
Onchocerciasis causes severe itching, serious skin disease and ocular damage leading to visual impairment or permanent blindness. It is associated with hanging groin, epilepsy, Nakalanga dwarfism and, most recently, nodding disease. This disease affected communities in 17 transmission foci in 37 districts of Uganda, where about 6.7 million people are once at risk. The efforts against onchocerciasis in Uganda commenced in the late 1940s, when vector control was launched using dichlorodiphenyltrichloroethane; by 1973, Simulium damnosum had been eliminated in the Victoria focus. Success outside of the Victoria focus was short-lived due to changes in government priorities and the political upheavals of the 1970s and 1980s. With the return of political stability, annual treatment with ivermectin through mass drug administration was launched in the early 1990s. Control of the disease has been successful, but there has been failure in interrupting transmission after more than 15 years. In 2007 Uganda launched a nationwide transmission elimination policy based on twice-per-year treatment and vector control/elimination, with a goal of eliminating river blindness nationwide by 2020. By 2017, 1 157 303 people from six foci had been freed from river blindness. This is the largest population ever declared free under World Health Organization elimination guidelines, providing evidence that elimination of river blindness in Africa is possible.
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Affiliation(s)
- Moses N Katabarwa
- Carter Center, One Copenhill Avenue, 453 Freedom Parkway, Atlanta, GA 30307, USA
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Thomas R Unnasch
- University of South Florida, Global Health Infectious Disease Research, College of Public Health, Tampa, FL, USA
| | - Rolf Garms
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Lauri Hudson-Davis
- Carter Center, One Copenhill Avenue, 453 Freedom Parkway, Atlanta, GA 30307, USA
| | | | | | - Johnson Ngorok
- Sightsavers, East African Development Bank Building, Kampala, Uganda
| | | | - Frank O Richards
- Carter Center, One Copenhill Avenue, 453 Freedom Parkway, Atlanta, GA 30307, USA
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11
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Shey RA, Ghogomu SM, Esoh KK, Nebangwa ND, Shintouo CM, Nongley NF, Asa BF, Ngale FN, Vanhamme L, Souopgui J. In-silico design of a multi-epitope vaccine candidate against onchocerciasis and related filarial diseases. Sci Rep 2019; 9:4409. [PMID: 30867498 PMCID: PMC6416346 DOI: 10.1038/s41598-019-40833-x] [Citation(s) in RCA: 200] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 02/25/2019] [Indexed: 01/02/2023] Open
Abstract
Onchocerciasis is a parasitic disease with high socio-economic burden particularly in sub-Saharan Africa. The elimination plan for this disease has faced numerous challenges. A multi-epitope prophylactic/therapeutic vaccine targeting the infective L3 and microfilaria stages of the parasite's life cycle would be invaluable to achieve the current elimination goal. There are several observations that make the possibility of developing a vaccine against this disease likely. For example, despite being exposed to high transmission rates of infection, 1 to 5% of people have no clinical manifestations of the disease and are thus considered as putatively immune individuals. An immuno-informatics approach was applied to design a filarial multi-epitope subunit vaccine peptide consisting of linear B-cell and T-cell epitopes of proteins reported to be potential novel vaccine candidates. Conservation of the selected proteins and predicted epitopes in other parasitic nematode species suggests that the generated chimera could be helpful for cross-protection. The 3D structure was predicted, refined, and validated using bioinformatics tools. Protein-protein docking of the chimeric vaccine peptide with the TLR4 protein predicted efficient binding. Immune simulation predicted significantly high levels of IgG1, T-helper, T-cytotoxic cells, INF-γ, and IL-2. Overall, the constructed recombinant putative peptide demonstrated antigenicity superior to current vaccine candidates.
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Affiliation(s)
- Robert Adamu Shey
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies, Belgium.,Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Stephen Mbigha Ghogomu
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Kevin Kum Esoh
- Department of Biochemistry, Faculty of Science, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Neba Derrick Nebangwa
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Cabirou Mounchili Shintouo
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Nkemngo Francis Nongley
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Bertha Fru Asa
- Department of Public Health and Hygiene, Faculty of Health Science, University of Buea, Buea, Cameroon
| | - Ferdinand Njume Ngale
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies, Belgium.,Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Luc Vanhamme
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Jacob Souopgui
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies, Belgium.
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12
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Michael E, Smith ME, Katabarwa MN, Byamukama E, Griswold E, Habomugisha P, Lakwo T, Tukahebwa E, Miri ES, Eigege A, Ngige E, Unnasch TR, Richards FO. Substantiating freedom from parasitic infection by combining transmission model predictions with disease surveys. Nat Commun 2018; 9:4324. [PMID: 30337529 PMCID: PMC6193962 DOI: 10.1038/s41467-018-06657-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/14/2018] [Indexed: 11/22/2022] Open
Abstract
Stopping interventions is a critical decision for parasite elimination programmes. Quantifying the probability that elimination has occurred due to interventions can be facilitated by combining infection status information from parasitological surveys with extinction thresholds predicted by parasite transmission models. Here we demonstrate how the integrated use of these two pieces of information derived from infection monitoring data can be used to develop an analytic framework for guiding the making of defensible decisions to stop interventions. We present a computational tool to perform these probability calculations and demonstrate its practical utility for supporting intervention cessation decisions by applying the framework to infection data from programmes aiming to eliminate onchocerciasis and lymphatic filariasis in Uganda and Nigeria, respectively. We highlight a possible method for validating the results in the field, and discuss further refinements and extensions required to deploy this predictive tool for guiding decision making by programme managers. The decision when to stop an intervention is a critical component of parasite elimination programmes, but reliance on surveillance data alone can be inaccurate. Here, Michael et al. combine parasite transmission model predictions with disease survey data to more reliably determine when interventions can be stopped.
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Affiliation(s)
- Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
| | - Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Moses N Katabarwa
- Emory University and The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA, 30307, USA
| | | | - Emily Griswold
- Emory University and The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA, 30307, USA
| | | | - Thomson Lakwo
- Vector Control Division, Ministry of Health, 15 Bombo Road, P.O. Box 1661, Kampala, Uganda
| | - Edridah Tukahebwa
- Vector Control Division, Ministry of Health, 15 Bombo Road, P.O. Box 1661, Kampala, Uganda
| | - Emmanuel S Miri
- The Carter Center, Nigeria, 1 Jeka Kadima Street off Tudun Wada Ring Road, Jos, Nigeria
| | - Abel Eigege
- The Carter Center, Nigeria, 1 Jeka Kadima Street off Tudun Wada Ring Road, Jos, Nigeria
| | - Evelyn Ngige
- Federal Ministry of Health, Federal Sceretariat, Garki-Abuja, Nigeria
| | - Thomas R Unnasch
- Global Health Infectious Disease Research, College of Public Health, University of South Florida, 33620, Tampa, FL, USA
| | - Frank O Richards
- Emory University and The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA, 30307, USA
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13
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Walker M, Stolk WA, Dixon MA, Bottomley C, Diawara L, Traoré MO, de Vlas SJ, Basáñez MG. Modelling the elimination of river blindness using long-term epidemiological and programmatic data from Mali and Senegal. Epidemics 2018; 18:4-15. [PMID: 28279455 PMCID: PMC5340858 DOI: 10.1016/j.epidem.2017.02.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 11/11/2022] Open
Abstract
Onchocerciasis is earmarked for elimination in some African countries by 2020/2025. 15+ years of ivermectin treatment drove infection prevalence to zero in areas of Mali & Senegal. Data-driven model projections are used to evaluate the risk of infection resurgence. Latent infections can initiate slow resurgence in communities with high transmission propensity. Highly sensitive and long-term surveillance will be necessary to verify elimination.
The onchocerciasis transmission models EPIONCHO and ONCHOSIM have been independently developed and used to explore the feasibility of eliminating onchocerciasis from Africa with mass (annual or biannual) distribution of ivermectin within the timeframes proposed by the World Health Organization (WHO) and endorsed by the 2012 London Declaration on Neglected Tropical Diseases (i.e. by 2020/2025). Based on the findings of our previous model comparison, we implemented technical refinements and tested the projections of EPIONCHO and ONCHOSIM against long-term epidemiological data from two West African transmission foci in Mali and Senegal where the observed prevalence of infection was brought to zero circa 2007–2009 after 15–17 years of mass ivermectin treatment. We simulated these interventions using programmatic information on the frequency and coverage of mass treatments and trained the model projections using longitudinal parasitological data from 27 communities, evaluating the projected outcome of elimination (local parasite extinction) or resurgence. We found that EPIONCHO and ONCHOSIM captured adequately the epidemiological trends during mass treatment but that resurgence, while never predicted by ONCHOSIM, was predicted by EPIONCHO in some communities with the highest (inferred) vector biting rates and associated pre-intervention endemicities. Resurgence can be extremely protracted such that low (microfilarial) prevalence between 1% and 5% can be maintained for 3–5 years before manifesting more prominently. We highlight that post-treatment and post-elimination surveillance protocols must be implemented for long enough and with high enough sensitivity to detect possible residual latent infections potentially indicative of resurgence. We also discuss uncertainty and differences between EPIONCHO and ONCHOSIM projections, the potential importance of vector control in high-transmission settings as a complementary intervention strategy, and the short remaining timeline for African countries to be ready to stop treatment safely and begin surveillance in order to meet the impending 2020/2025 elimination targets.
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Affiliation(s)
- Martin Walker
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research, Imperial College London, Norfolk Place, W2 1 PG, London, UK; Department of Pathobiology and Population Sciences and London Centre for Neglected Tropical Disease Research, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK.
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Matthew A Dixon
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands; MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research, Imperial College London, Norfolk Place, W2 1 PG, London, UK
| | - Christian Bottomley
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands; MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Lamine Diawara
- Inter-Country Support Team for West Africa, World Health Organization 158, Place de l'Indépendance 03 BP 7019, Ouagadougou 03, Burkina Faso
| | - Mamadou O Traoré
- Programme National de Lutte contre l'Onchocercose (PNLO), Direction Nationale de la Santé (DNS), B.P. 233, Bamako, Mali
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - María-Gloria Basáñez
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands; MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research, Imperial College London, Norfolk Place, W2 1 PG, London, UK
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14
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Jacob BG, Loum D, Lakwo TL, Katholi CR, Habomugisha P, Byamukama E, Tukahebwa E, Cupp EW, Unnasch TR. Community-directed vector control to supplement mass drug distribution for onchocerciasis elimination in the Madi mid-North focus of Northern Uganda. PLoS Negl Trop Dis 2018; 12:e0006702. [PMID: 30148838 PMCID: PMC6128654 DOI: 10.1371/journal.pntd.0006702] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/07/2018] [Accepted: 07/19/2018] [Indexed: 11/19/2022] Open
Abstract
Background Onchocerciasis a neglected tropical disease that historically has been a major cause of morbidity and an obstacle to economic development in the developing world. It is caused by infection with Onchocerca volvulus, which is transmitted by black flies of the genus Simulium. The discovery of the potent effect of Mectizan (ivermectin) on O. volvulus microfilariae and the decision by its manufacturer to donate the drug for onchocerciasis spurred the implementation of international programs to control and, more recently, eliminate this scourge. These programs rely primarily on mass distribution of ivermectin (MDA) to the afflicted populations. However, MDA alone will not be sufficient to eliminate onchocerciasis where transmission is intense and where ivermectin MDA is precluded by co-endemicity with Loa loa. Vector control will likely be required as a supplemental intervention in these situations. Methodology/Principal findings Because biting by the black fly vectors is often a major nuisance in onchocerciasis afflicted communities, we hypothesized that community members might be mobilized to clear the breeding sites of the vegetation that represents the primary black fly larvae attachment point. We evaluated the effect of such a community based "slash and clear" intervention in multiple communities in Northern Uganda. Slash and Clear resulted in 89–99% declines in vector biting rates. The effect lasted up to 120 days post intervention. Conclusions/Significance Slash and clear might represent an effective, inexpensive, community- based tool to supplement ivermectin distribution as a contributory method to eliminate onchocerciasis and prevent recrudescence. River blindness is one of the most important causes of morbidity in the developing world. The discovery of ivermectin and the decision by its manufacturer to donate the drug for river blindness spawned the development of programs to eliminate river blindness through mass treatment of afflicted populations. But ivermectin alone will not eliminate river blindness in much of Africa; additional interventions are necessary. We show that a simple community-based approach to controlling the black fly vector results in dramatic reductions in the vector population. Such a community-based approach to vector control will be compatible with the community-driven mass drug administration programs distributing ivermectin for onchocerciasis elimination in Africa. This should help reduce the time needed to obtain elimination and help prevent recrudescence once elimination is attained.
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Affiliation(s)
- Benjamin G. Jacob
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL United States of America
| | - Denis Loum
- Nwoya District Local Government, Nwoya, Uganda
| | | | - Charles R. Katholi
- Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, AL United States of America
| | | | | | | | - Eddie W. Cupp
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States of America
| | - Thomas R. Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL United States of America
- * E-mail:
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15
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Richards FO, Katabarwa M, Bekele F, Tadesse Z, Mohammed A, Sauerbrey M, Dominguez-Vazquez A, Rodriguez-Perez MA, Fernández-Santos NA, Rizzo N, Schuler Martínez HR, Lovato Silva R, Morales Monroy Z, Habomugisha P, Oguttu DW, Zarroug IMA, Aziz NA, Unnasch TR. Operational Performance of the Onchocerca volvulus "OEPA" Ov16 ELISA Serological Assay in Mapping, Guiding Decisions to Stop Mass Drug Administration, and Posttreatment Surveillance Surveys. Am J Trop Med Hyg 2018; 99:749-752. [PMID: 30014821 DOI: 10.4269/ajtmh.18-0341] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Onchocerciasis is a neglected tropical disease targeted for elimination. The World Health Organization (WHO) has developed guidelines for the verification of onchocerciasis elimination that include entomological and epidemiological criteria. The latter require demonstrating with statistical confidence that the infection prevalence in children is less than 0.1%, necessitating an assay with a high degree of specificity. We present an analysis of the performance of the Onchocerciasis Elimination Program for the Americas (OEPA) version of the Ov16 enzyme-linked immunosorbant assay (ELISA) when used under operational conditions. In Africa and Latin America, the assay demonstrated 99.98% specificity in 69,888 children in 20 foci where transmission was believed to be interrupted. The assay produced a prevalence estimate equal to that of skin snip microscopy when applied in putatively hypo-endemic zones of Ethiopia. The OEPA Ov16 ELISA demonstrated the specificity required to be effectively deployed to verify transmission elimination under the WHO guidelines, while exhibiting a sensitivity equivalent to skin snip microscopy to identify hypo-endemic areas.
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Affiliation(s)
| | | | | | | | | | - Mauricio Sauerbrey
- Onchocerciasis Elimination Program for the Americas, Guatemala City, Guatemala
| | | | | | | | - Nidia Rizzo
- Centro de Estudios en Salud of the Universidad del Valle de, Guatemala (UVG), Guatemala City, Guatemala
| | | | | | | | | | - David W Oguttu
- NTD Control Program, Vector Control Division, Kampala, Uganda
| | | | | | - Thomas R Unnasch
- Center for Global Health Infectious Disease Research, The University of South Florida, Tampa, Florida
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16
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Nicholls RS, Duque S, Olaya LA, López MC, Sánchez SB, Morales AL, Palma GI. Elimination of onchocerciasis from Colombia: first proof of concept of river blindness elimination in the world. Parasit Vectors 2018; 11:237. [PMID: 29642939 PMCID: PMC5896109 DOI: 10.1186/s13071-018-2821-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/26/2018] [Indexed: 11/22/2022] Open
Abstract
Background Onchocerciasis is a chronic parasitic infection originally endemic in 13 discrete regional foci distributed among six countries of Latin America (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela). In Colombia, this disease was discovered in 1965 in the Pacific Coast of the country. The National Onchocerciasis Elimination Program was established in 1993 with the aim of eliminating disease morbidity and infection transmission. In 2013, the World Health Organization (WHO) verified Colombia as free of onchocerciasis, becoming the first country in the world to reach such a goal. This report provides the empirical evidence of the elimination of Onchocerca volvulus transmission by Simulium exiguum (s.l.) after 12 years of 6-monthly mass drug administration of Mectizan® (ivermectin) to all the eligible residents living in this endemic area. Methods From 1996 onwards, a biannual community-based mass ivermectin administration programme was implemented, complemented by health education and community participation. In-depth parasitological, serological and entomological surveys were conducted periodically between 1998 and 2007 to evaluate the impact of ivermectin treatment according to the 2001 WHO guidelines. When the interruption of parasite transmission was demonstrated, the drug distribution ceased and a three-year post-treatment surveillance (PTS) period (2008–2010) was initiated. Results After 23 rounds of treatment, parasitological and ophthalmological assessments showed absence of microfilariae in skin and anterior chamber of the eyes. Serological tests proved lack of antibodies against O. volvulus in children under 10 years-old. A total of 10,500 S. exiguum flies tested by PCR had no L3 infection (infectivity rate = 0.0095%; 95% CI: 0.0029–0.049) during 2004, indicating interruption of parasite transmission. However, biannual ivermectin treatments continued until 2007 followed by a 3-year PTS period at the end of which 13,481 flies were analyzed and no infective flies were found (infectivity rate = 0%; 95% CI: 0.0–0.014). Conclusions These results fulfilled the WHO criteria for onchocerciasis elimination. Consequently, in 2013 Colombia was verified as free of onchocerciasis, demonstrating that elimination of this neglected tropical disease is an achievable goal and paving the way for an elimination agenda to be followed by other endemic countries in Latin America and Africa.
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Affiliation(s)
- Rubén Santiago Nicholls
- Grupo de Parasitología, Instituto Nacional de Salud, Avenida Calle 26 No. 51-20, Bogotá, DC CP 111321, Colombia.
| | - Sofía Duque
- Grupo de Parasitología, Instituto Nacional de Salud, Avenida Calle 26 No. 51-20, Bogotá, DC CP 111321, Colombia
| | - Luz Adriana Olaya
- Laboratorio Departamental de Salud Pública, Secretaría Departamental de Salud del Cauca, Calle 5 No. 15-57, Popayán, Cauca, CP 190003, Colombia
| | - Myriam Consuelo López
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional de Colombia, Ciudad Universitaria, Bogotá, DC CP 111321, Colombia
| | - Sol Beatriz Sánchez
- Consultant Health Education, Colombian Onchocerciasis Elimination Program, Carrera 93 # 16-90, Cali, CP 760032, Colombia
| | - Alba Lucía Morales
- Onchocerciasis Elimination Program for the Americas (OEPA), 14 calle 3-51, zona 10, Edificio Murano Center, CP 01010, Guatemala, Guatemala
| | - Gloria Inés Palma
- Departamento de Microbiologia, Facultad de Salud, Universidad del Valle, Campus San Fernando, Calle 4B No. 36-00, CP 760043, Cali, Colombia
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Elhassan E, Zhang Y, Bush S, Molyneux D, Kollmann MKH, Sodahlon Y, Richards F. The role of the NGDO Coordination Group for the Elimination of Onchocerciasis. Int Health 2018; 10:i97-i101. [PMID: 29471339 DOI: 10.1093/inthealth/ihx050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 11/30/2017] [Indexed: 11/14/2022] Open
Abstract
The NGDO Coordination Group for the Control of Onchocerciasis was launched in 1992, and with the paradigm shift from control of disease to elimination of onchocerciasis transmission, the Group shifted its orientation to that new paradigm in 2013. It also changed its name, replacing 'control' with 'elimination.' In doing so, the Group has repositioned itself to build on the successes of the past to finish the job it began over 25 years ago.
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Affiliation(s)
| | | | | | - David Molyneux
- Liverpool School of Tropical Medicine and Hygiene, Liverpool, UK
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18
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Lakwo T, Ukety T, Bakajika D, Tukahebwa E, Awaca P, Amazigo U. "Cross-border collaboration in onchocerciasis elimination in Uganda: progress, challenges and opportunities from 2008 to 2013". Global Health 2018; 14:16. [PMID: 29409509 PMCID: PMC5801695 DOI: 10.1186/s12992-018-0333-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 01/18/2018] [Indexed: 11/23/2022] Open
Abstract
Background Until recently onchocerciasis was prevalent in 37 out of 112 districts of Uganda with at least 3.8 million people at risk of contracting the disease, but following the launching of community-directed treatment with ivermectin (CDTI) in 1996 and the adoption of an onchocerciasis elimination policy in 2007, the country has made significant progress in combating the disease. By 2015, interruption of transmission had been achieved in ten of the 17 onchocerciasis foci, but cross-border foci remained particularly problematic, and therefore within the onchocerciasis elimination framework, Uganda embarked upon addressing these issues with its neighbouring countries, namely the Democratic Republic of Congo (DRC) and South Sudan. This paper summarises the experience of Uganda in addressing cross-border issues on onchocerciasis elimination with DRC. Main achievements and lessons learned The key achievements comprise of the adoption of an elimination policy by the Government of Uganda, cross-border meetings, training DRC technical staff and entomological/ epidemiological surveys. The first strategy meeting was held in Kampala in 2008, but the second strategy meeting was not held in Kinshasa until 2013. The involvement of the high-level officials from the Ministry of Health of DRC was critical for the success of the second strategy meeting, and was precipitated by collaboration to control an outbreak of Ebola Virus. Both meetings demonstrated the political commitment of endemic countries and allowed the implementation of a joint action plan. Important steps in establishing a mutually respected elimination targets was agreed on during cross border meetings. The African Programme for Onchocerciasis Control facilitated and funded these initial meetings, thus overcoming some political and financial challenges faced by both countries. This highlighted the need for multilateral organisations such as the Expanded Special Project for the Elimination of Neglected Tropical Diseases in cross-border activities for other Neglected Tropical Diseases. The collaboration between both countries facilitated the training of technical staff from DRC in entomology which facilitated joint cross-border activities to update the epidemiological understanding of onchocerciasis in Beni and Mahagi districts in North Kivu and Ituri Provinces respectively. In Nebbi district, Uganda, 23.7% of crabs were infested by the vector Simulium neavei compared with 6.3% in Mahagi district, DRC. Rapid Epidemiological Assessment (REA) revealed nodule prevalence of 3.2% and onchodermatitis at 26.4% from five villages in DRC. Conclusion Political commitment of both countries and the support from APOC allowed two cross-border meetings which were critical for the implementation of initial cross border activities for onchocerciasis elimination.
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Affiliation(s)
- Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda.
| | - Tony Ukety
- Retired Consultant Ophthalmologist & NTD Expert, Bunia, Democratic Republic of Congo
| | | | | | - Pitchouna Awaca
- Programme National pour la lutte des Maladies Tropicales Négligées et la Chimiothérapie Préventive (MTN/CTP), Kinshasa, Democratic Republic of Congo
| | - Uche Amazigo
- Pan-African Community Initiative on Education and Health (PACIEH) and University of Nigeria, Nsukka, Enugu, Nigeria
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19
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Luroni LT, Gabriel M, Tukahebwa E, Onapa AW, Tinkitina B, Tukesiga E, Nyaraga M, Auma AM, Habomugisha P, Byamukama E, Oguttu D, Katabarwa M, Unnasch TR. The interruption of Onchocerca volvulus and Wuchereria bancrofti transmission by integrated chemotherapy in the Obongi focus, North Western Uganda. PLoS One 2017; 12:e0189306. [PMID: 29253862 PMCID: PMC5734780 DOI: 10.1371/journal.pone.0189306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/22/2017] [Indexed: 11/18/2022] Open
Abstract
Intervention Few studies have documented the interruption of onchocerciasis and Lymphatic Filariasis (LF) by integrated chemotherapy in Uganda. The study describes the interruption of transmission of the two diseases co-endemic in Obongi focus, north western Uganda. Base line data for Onchocerciasis and LF were collected in 1994 and 2006, respectively. Annual mass drug administration for onchocerciasis (Ivermectin) and Lymphatic Filariasis (Ivermectin + albendazole) was conducted for 20 and 6 years, respectively. Thereafter, assessments by skin snip, larval searches in rivers and human landing catches were performed. Children <10 years were screened for IgG4 antibodies using Ov16 ELISA technique in 2013. LF Pre-TAS and TAS1 were conducted in sentinel sites. ITN coverage and utilization for the implementation unit was also reported. Intervention coverage Onchocerciasis treatment coverage was <80% but improved with the introduction of CDTI in 1999. While for LF, effective coverage of >65% was achieved in the six treatment rounds. Household ownership of ITN’s and utilization was 96% and 72.4%., respectively. Impact Parasitological examinations conducted for onchocerciasis among 807 adults and children, revealed a reduction in mf prevalence from 58% in 1994 to 0% in 2012. Entomological monitoring conducted at the two sites had no single Simulium damnosum fly caught. Serological analysis using Ov16 ELISA for onchocerciasis revealed that out of the 3,308 children <10 years old screened in 2013, only 3/3308 (0.091%) positive cases were detected. All Ov16 positive children were negative when tested for patent infection by skin snip PCR. A reduction in LF microfilaria prevalence from 2.5% (n = 13/522) in 2006 to 0.0% (n = 602) in 2014 was observed. LF TAS1 conducted in 2015 among 1,532 children 6–7 years, all were negative for antigens of W. bancrofti. Conclusion The results concluded that interruption of onchocerciasis and LF has been achieved.
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Affiliation(s)
| | - Matwale Gabriel
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | | | | | - Michael Nyaraga
- Moyo District Local Government, Medical Department, Moyo, Uganda
| | - Anna Mary Auma
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | - David Oguttu
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Thomas Raymond Unnasch
- University of South Florida, Global Health Infectious Disease Research, College of Public Health, Tampa, FL, United States of America
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Loum D, Katholi CR, Lakwo T, Habomugisha P, Tukahebwa EM, Unnasch TR. Evaluation of Community-Directed Operation of Black Fly Traps for Entomological Surveillance of Onchocerca volvulus Transmission in the Madi-Mid North Focus of Onchocerciasis in Northern Uganda. Am J Trop Med Hyg 2017; 97:1235-1242. [PMID: 29031285 DOI: 10.4269/ajtmh.17-0244] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Entomological measures of transmission are important metrics specified by the World Health Organization to document the suppression and interruption of transmission of Onchocerca volvulus, the causative agent of onchocerciasis. These metrics require testing of large numbers of vector black flies. Black fly collection has relied on human landing collections, which are inefficient and potentially hazardous. As the focus of the international community has shifted from onchocerciasis control to elimination, replacement of human landing collections has become a priority. The Esperanza window trap (EWT) has shown promise as an alternative method for collection of Simulium damnosum s.l., the primary vector of O. volvulus in Africa. Here, we report the results of a community-based trial of the EWT in northern Uganda. Traps operated by residents were compared with human landing collections in two communities over 5 months. Three traps, when operated by a single village resident, collected over four times as many S. damnosum as did the two-men collection team. No significant differences were noted among the bait formulations. The results suggest that EWTs may be effectively operated by community residents and that the trap represents a viable alternative to human landing collections for entomological surveillance of O. volvulus transmission.
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Affiliation(s)
- Denis Loum
- Nwoya District Local Government, Nwoya, Uganda
| | - Charles R Katholi
- Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | - Thomas R Unnasch
- Global Health Infectious Disease Research, College of Public Health, University of South Florida, Tampa, Florida
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21
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Dieye Y, Storey HL, Barrett KL, Gerth-Guyette E, Di Giorgio L, Golden A, Faulx D, Kalnoky M, Ndiaye MKN, Sy N, Mané M, Faye B, Sarr M, Dioukhane EM, Peck RB, Guinot P, de los Santos T. Feasibility of utilizing the SD BIOLINE Onchocerciasis IgG4 rapid test in onchocerciasis surveillance in Senegal. PLoS Negl Trop Dis 2017; 11:e0005884. [PMID: 28972982 PMCID: PMC5640270 DOI: 10.1371/journal.pntd.0005884] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 10/13/2017] [Accepted: 08/18/2017] [Indexed: 11/25/2022] Open
Abstract
As effective onchocerciasis control efforts in Africa transition to elimination efforts, different diagnostic tools are required to support country programs. Senegal, with its long standing, successful control program, is transitioning to using the SD BIOLINE Onchocerciasis IgG4 (Ov16) rapid test over traditional skin snip microscopy. The aim of this study is to demonstrate the feasibility of integrating the Ov16 rapid test into onchocerciasis surveillance activities in Senegal, based on the following attributes of acceptability, usability, and cost. A cross-sectional study was conducted in 13 villages in southeastern Senegal in May 2016. Individuals 5 years and older were invited to participate in a demographic questionnaire, an Ov16 rapid test, a skin snip biopsy, and an acceptability interview. Rapid test technicians were interviewed and a costing analysis was conducted. Of 1,173 participants, 1,169 (99.7%) agreed to the rapid test while 383 (32.7%) agreed to skin snip microscopy. The sero-positivity rate of the rapid test among those tested was 2.6% with zero positives 10 years and younger. None of the 383 skin snips were positive for Ov microfilaria. Community members appreciated that the rapid test was performed quickly, was not painful, and provided reliable results. The total costs for this surveillance activity was $22,272.83, with a cost per test conducted at $3.14 for rapid test, $7.58 for skin snip microscopy, and $13.43 for shared costs. If no participants had refused skin snip microscopy, the total cost per method with shared costs would have been around $16 per person tested. In this area with low onchocerciasis sero-positivity, there was high acceptability and perceived value of the rapid test by community members and technicians. This study provides evidence of the feasibility of implementing the Ov16 rapid test in Senegal and may be informative to other country programs transitioning to Ov16 serologic tools. As onchocerciasis control programs succeed and transition to elimination efforts, different diagnostic tools are needed. The goal of this study was to determine if integrating the Ov16 rapid test is feasible based on acceptability, usability, and cost. A study was conducted in 13 villages in southeastern Senegal in May 2016. Community members were invited to participate in a demographic questionnaire, a rapid test, a skin snip biopsy, and an acceptability interview. Technicians were also interviewed and a costing analysis was conducted. Out of 1,173 participants, 1,169 (99.7%) agreed to the rapid test while 383 (32.7%) agreed to skin snip microscopy. The rapid test result was reactive in 2.6% of those tested, while none of the skin snips were positive. Community members thought the rapid test was performed quickly, was not painful, and provided reliable results. If no one had refused skin snip microscopy, the total cost would have been around $16 per person tested for either method. In this area with little if any remaining onchocerciasis, there was high acceptability and perceived value of the rapid test. This study suggests that implementing the Ov16 rapid test in Senegal is feasible and these findings may be informative to other country programs.
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Affiliation(s)
- Yakou Dieye
- PATH, Seattle, Washington, United States of America
| | - Helen L Storey
- PATH, Seattle, Washington, United States of America
- * E-mail:
| | | | | | | | | | - Dunia Faulx
- PATH, Seattle, Washington, United States of America
| | | | | | - Ngayo Sy
- Senegal Ministry of Health and Social Action, Dakar, Senegal
| | - Malang Mané
- Senegal Ministry of Health and Social Action, Dakar, Senegal
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Rodríguez-Pérez MA, Garza-Hernández JA, Salinas-Carmona MC, Fernández-Salas I, Reyes-Villanueva F, Real-Najarro O, Cupp EW, Unnasch TR. The esperanza window trap reduces the human biting rate of Simulium ochraceum s.l. in formerly onchocerciasis endemic foci in Southern Mexico. PLoS Negl Trop Dis 2017; 11:e0005686. [PMID: 28686665 PMCID: PMC5517070 DOI: 10.1371/journal.pntd.0005686] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 07/19/2017] [Accepted: 06/07/2017] [Indexed: 11/18/2022] Open
Abstract
Background The Esperanza Window Trap (EWT) baited with CO2 and human sweat compounds is attractive to Simulium ochraceum s.l., the primary vector of Onchocerca volvulus in the historically largest endemic foci in México and Guatemala. Methodology/Principal findings The ability of the EWT to locally reduce numbers of questing S. ochraceum s.l. was evaluated in two formerly onchocerciasis endemic communities in Southern México. At each community, two EWTs were placed in or near a school or household and flies were collected sequentially for a total of 10 days. Black fly collections were then carried out for an additional 10 days in the absence of the EWTs. Flies were also collected outside the dwellings to control for variations in the local fly populations. When the EWTs were present, there was a significant reduction in the human biting rate at both the household and school locations at collection sites, with a greater effect observed in the schools. Conclusions/Significance These results indicate that the EWTs not only have potential as a black fly monitoring tool but may be used for reducing personal exposure to fly bites in Mesoamerica. The Esperanza window trap (EWT), when used in large numbers (3-4/household and >90% coverage) and baited with human sweat compounds and CO2, can be used to collect epidemiologically significant numbers of Simulium ochraceum s.l., the primary vector of Onchocerca volvulus in the historically largest endemic foci in México and Guatemala. In the present study, we evaluated the ability of the EWT to reduce the personal biting rate by questing S. ochraceum s.l. in two formerly onchocerciasis endemic communities in Southern México. At each community, two EWTs were placed in or near a school or household and flies were collected sequentially for a total of 10 days. Black fly collections were then carried out for an additional 10 days in the absence of the EWTs. When the EWTs were present, there was a significant reduction in the human biting rate at each of the four collection sites, varying from 14% to 51%. This study demonstrates that the EWTs have potential both as a black fly monitoring and personal exposure reduction tool in Mesoamerica.
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Affiliation(s)
- Mario A. Rodríguez-Pérez
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, Tamaulipas, México
- * E-mail: ,
| | - Javier A. Garza-Hernández
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, Tamaulipas, México
- Laboratorio de Biologia Molecular, Universidad Autonoma Agraria Antonio Narro, Unidad Laguna, Torreon, Coahuila. C. P., México
| | | | - Ildefonso Fernández-Salas
- Centro Regional de Investigación en Salud Pública, Instituto Nacional de Salud Pública, Tapachula, Chiapas, México
| | | | - Olga Real-Najarro
- Consejería de Educación, Madrid, España. Calle Maestro 19, Leganés (Madrid) Madrid, España
| | - Eddie W. Cupp
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Thomas R. Unnasch
- Global Health Infectious Disease Research Program, Department of Global Health, University of South Florida, Tampa, Florida, United States of America
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Lakwo T, Garms R, Wamani J, Tukahebwa E, Byamukama E, Onapa A, Tukesiga E, Katamanywa J, Begumisa S, Habomugisha P, Oguttu D, Byamukama E, Richards F, Unnasch T, Katabarwa M. Interruption of the transmission of Onchocerca volvulus in the Kashoya-Kitomi focus, western Uganda by long-term ivermectin treatment and elimination of the vector Simulium neavei by larviciding. Acta Trop 2017; 167:128-136. [PMID: 28034767 DOI: 10.1016/j.actatropica.2016.12.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 12/10/2016] [Accepted: 12/23/2016] [Indexed: 11/26/2022]
Abstract
Uganda is the only country in sub-Saharan Africa whose onchocerciasis elimination programme extensively uses vector control and biannual treatment with ivermectin. The purpose of this study was to assess the impact of combined strategies on interrupting onchocerciasis transmission in the Kashoya-Kitomi focus. Mass Drug Administration annually (13 years) followed by biannual treatments (6 years) and ground larviciding (36 cycles in 3 years) with temephos (Abate®, EC500) against Simulium neavei were conducted. Routine fly catches were conducted for over seven years in six catching sites and freshwater crabs Potamonautes aloysiisabaudiae were examined for immature stages of Simulium neavei. Epidemiological assessments by skin snip were performed in 2004 and 2013. Collection of dry blood spots (DBS) from children <10 years for IgG4 antibodies analysis were done in 2010 and 2013. Treatment coverage with ivermectin improved with introduction of biannual treatment strategy. Microfilaria prevalence reduced from 85% in 1991 to 62% in 2004; and to only 0.5% in 2013. Crab infestation reduced from 59% in 2007 to 0% in 2013 following ground larviciding. Comparison of total fly catches before and after ground larviciding revealed a drop from 5334 flies in 2007 to 0 flies in 2009. Serological assays conducted among 1,362 children in 2010 revealed 11 positive cases (0.8%; 95% CI: 0.4%-1.2%). However, assessment conducted on 3246 children in 2013 revealed five positives, giving point prevalence of 0.15%; 95% CI: 0.02%-0.28%. Four of the five children subjected to O-150 PCR proved negative. The data show that transmission of onchocerciasis has been interrupted based on national and WHO Guidelines of 2012 and 2016, respectively.
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Cheke RA. Factors affecting onchocerciasis transmission: lessons for infection control. Expert Rev Anti Infect Ther 2017; 15:377-386. [PMID: 28117596 DOI: 10.1080/14787210.2017.1286980] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Onchocerca volvulus infects in excess of 15 million people. The vectors are Simulium blackflies, varieties of which differ in their ecologies, behavior and vectorial abilities. Control of the vectors and mass administrations of ivermectin have succeeded in reducing prevalences with elimination achieved in some foci, particularly in Central and southern America. In Africa, progress towards elimination has been less successful. Areas covered: Even with community directed treatment with ivermectin (CDTI), control has been difficult in African areas with initial prevalences in excess of 55%, especially if only annual treatments are dispensed. This is partly attributable to insufficient coverage, but the appearance of incipiently resistant non-responding parasites and lack of attention to vector biology in modeling and planning outcomes of intervention programmes have also played their parts, with recrudescence now appearing in some treated areas. Expert commentary: The biology of onchocerciasis is complex involving different vectors with differing abilities to transmit parasites, diverse pathologies related to geographical and parasite variations and endosymbionts in both parasite and vector. Modeling to predict epidemiological and control outcomes is addressing this complexity but more attention needs to be given to the vectors' roles to further understanding of where and when control measures will succeed.
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Affiliation(s)
- Robert A Cheke
- a Agriculture, Health and Environment Department, Natural Resources Institute , University of Greenwich at Medway , Kent , UK.,b Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) , Imperial College London , London , UK
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Wilson NO, Badara Ly A, Cama VA, Cantey PT, Cohn D, Diawara L, Direny A, Fall M, Feeser KR, Fox LM, Kabore A, Seck AF, Sy N, Ndiaye D, Dubray C. Evaluation of Lymphatic Filariasis and Onchocerciasis in Three Senegalese Districts Treated for Onchocerciasis with Ivermectin. PLoS Negl Trop Dis 2016; 10:e0005198. [PMID: 27926918 PMCID: PMC5142766 DOI: 10.1371/journal.pntd.0005198] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/18/2016] [Indexed: 11/19/2022] Open
Abstract
In Africa, onchocerciasis and lymphatic filariasis (LF) are co-endemic in many areas. Current efforts to eliminate both diseases are through ivermectin-based mass drug administration (MDA). Years of ivermectin distribution for onchocerciasis may have interrupted LF transmission in certain areas. The Kédougou region, Senegal, is co-endemic for LF and onchocerciasis. Though MDA for onchocerciasis started in 1988, in 2014 albendazole had not yet been added for LF. The objective of this study was to assess in an integrated manner the LF and onchocerciasis status in the three districts of the Kédougou region after ≥10 years of ivermectin-based MDA. The study employed an African Programme for Onchocerciasis Control (APOC) onchocerciasis-related methodology. In the three districts, 14 villages close to three rivers that have Simulium damnosum breeding sites were surveyed. Convenience sampling of residents ≥5 years old was performed. Assessment for LF antigenemia by immunochromatographic testing (ICT) was added to skin snip microscopy for onchocerciasis. Participants were also tested for antibodies against Wb123 (LF) and Ov16 (onchocerciasis) antigens. In two districts, no participants were ICT or skin snip positive. In the third district, 3.5% were ICT positive and 0.7% were skin snip positive. In all the three districts, Wb123 prevalence was 0.6%. Overall, Ov16 prevalence was 6.9%. Ov16 prevalence among children 5-9 years old in the study was 2.5%. LF antigenemia prevalence was still above treatment threshold in one district despite ≥10 years of ivermectin-based MDA. The presence of Ov16 positive children suggested recent transmission of Onchocerca volvulus. This study showed the feasibility of integrated evaluation of onchocerciasis and LF but development of integrated robust methods for assessing transmission of both LF and onchocerciasis are needed to determine where MDA can be stopped safely in co-endemic areas.
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Affiliation(s)
- Nana O. Wilson
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
- * E-mail: (NOW); (CD)
| | | | - Vitaliano A. Cama
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - Paul T. Cantey
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - Daniel Cohn
- RTI International, Washington, DC, United States of America
| | - Lamine Diawara
- World Health Organization, Regional Office for Africa, Senegal
- African Programme for Onchocerciasis Control Representative, Ougadougou, Burkina Faso
| | | | | | - Karla R. Feeser
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - LeAnne M. Fox
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - Achille Kabore
- RTI International, Washington, DC, United States of America
| | - Amadou F. Seck
- Ministère de la Santé et de l’Action Sociale, Dakar, Senegal
| | - Ngayo Sy
- Service de Lutte Antiparasitaire, Ministère de la Santé et de l’Action Sociale, Thies, Senegal
| | | | - Christine Dubray
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
- * E-mail: (NOW); (CD)
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26
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Golden A, Faulx D, Kalnoky M, Stevens E, Yokobe L, Peck R, Karabou P, Banla M, Rao R, Adade K, Gantin RG, Komlan K, Soboslay PT, de Los Santos T, Domingo GJ. Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis. Parasit Vectors 2016; 9:338. [PMID: 27296630 PMCID: PMC4907250 DOI: 10.1186/s13071-016-1623-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/02/2016] [Indexed: 11/30/2022] Open
Abstract
Background Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection such as skin snip microfilaria and Onchocerca volvulus-specific seroconversion perform in near-elimination settings informs how to best use these markers. Methods All-age participants from 35 villages in Togo were surveyed in 2013 and 2014 for skin snip Onchocerca volvulus microfilaria and IgG4 antibody response by enzyme-linked immunosorbent assay (ELISA) to the Onchocerca volvulus-specific antigen Ov16. A Gaussian mixture model applying the expectation-maximization (EM) algorithm was used to determine seropositivity from Ov16 ELISA data. For a subset of participants (n = 434), polymerase chain reaction (PCR) was performed on the skin snips taken during surveillance. Results Within the 2,005 participants for which there was Ov16 ELISA data, O. volvulus microfilaremia prevalence and Ov16 seroprevalence were, 2.5 and 19.7 %, respectively, in the total population, and 1.6 and 3.6 % in children under 11. In the subset of 434 specimens for which ELISA, PCR, and microscopy data were generated, it was found that in children under 11 years of age, the anti-Ov16 IgG4 antibody response demonstrate a sensitivity and specificity of 80 and 97 %, respectively, against active infections as determined by combined PCR and microscopy on skin snips. Further analysis was performed in 34 of the 35 villages surveyed. These villages were stratified by all-age seroprevalence into three clusters: < 15 %; 15–20 %; and > 20 %. Age-dependence of seroprevalence for each cluster was best reflected by a two-phase force-of-infection (FOI) catalytic model. In all clusters, the lower of the two phases of FOI was associated with a younger age group, as reflected by the seroconversion rates for each phase. The age at which transition from lower to higher seroconversion, between the two phases of FOI, was found to be highest (older) for the cluster of villages with < 15 % seroprevalence and lowest (younger) for the cluster with the highest all-age seroprevalence. Conclusions The anti-Ov16 IgG4 antibody response is an accurate marker for active infection in children under 11 years of age in this population. Applying Ov16 surveillance to a broader age range provides additional valuable information for understanding progression toward elimination and can inform where targeted augmented interventions may be needed. Clustering of villages by all-age sero-surveillance allowed application of a biphasic FOI model to differentiate seroconversion rates for different age groups within the village cluster categories. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1623-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Dunia Faulx
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Eric Stevens
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Roger Peck
- Diagnostics Global Program, PATH, Seattle, WA, USA
| | | | - Méba Banla
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | | | - Kangi Adade
- National Onchocerciasis Control Programme, Kara, Togo
| | - Richard G Gantin
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Kossi Komlan
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Peter T Soboslay
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo.,Institute of Tropical Medicine, University Clinics of Tübingen, Tübingen, Germany
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Katabarwa MN, Katamanywa J, Lakwo T, Habomugisha P, Byamukama E, Oguttu D, Nahabwe C, Ngabirano M, Tukesiga E, Khainza A, Tukahebwa E, Unnasch TR, Richards FO, Garms R. The Imaramagambo Onchocerciasis Focus in Southwestern Uganda: Interruption of Transmission After Disappearance of the Vector Simulium neavei and Its Associated Freshwater Crabs. Am J Trop Med Hyg 2016; 95:417-425. [PMID: 27215297 PMCID: PMC4973193 DOI: 10.4269/ajtmh.16-0181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/04/2016] [Indexed: 11/22/2022] Open
Abstract
It was not until early 1990s that, when the Imaramagambo focus of southwest Uganda was mapped, mass treatment with a single annual dose of ivermectin for onchocerciaisis control commenced. However, comprehensive investigations on its transmission were launched after a nationwide policy for onchocerciasis elimination in 2007. Entomological surveys throughout the focus from 2007 to 2015 have yielded few or no freshwater crabs (Potamonautes aloysiisabaudiae), which serve as the obligate phoretic host of the larvae and pupae of the vector Simulium neavei. No S. neavei flies have been observed or collected since 2007. Skin snips (microscopy) from 294 individuals in 2008 were negative for skin microfilariae, and of the 462 persons analyzed by polymerase chain reaction skin snip poolscreen in 2009, only five (1.08%) persons were indicated as infected with onchocerciasis. All five of the positive persons were at least 40 years old. Serosurvey results showed negative exposure among 3,332 children in 2012 and 3,108 children in 2015. Both were within the upper bound of the 95% confidence interval of the prevalence estimate of 0.06%, which confirmed the elimination of onchocerciasis. Treatment coverage in Imaramagambo was generally poor, and transmission interruption of onchocerciasis could not be attributed solely to annual mass treatment with ivermectin. There was sufficient evidence to believe that the possible disappearance of the S. neavei flies, presumed to have been the main vector, may have hastened the demise of onchocerciasis in this focus.
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Affiliation(s)
| | | | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | - David Oguttu
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | | | | | | | | | | | - Rolf Garms
- Tropical Medicine Department, Bernhard Nocht Institute of Tropical Medicine, Hamburg, Germany
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28
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Frempong KK, Walker M, Cheke RA, Tetevi EJ, Gyan ET, Owusu EO, Wilson MD, Boakye DA, Taylor MJ, Biritwum NK, Osei-Atweneboana M, Basáñez MG. Does Increasing Treatment Frequency Address Suboptimal Responses to Ivermectin for the Control and Elimination of River Blindness? Clin Infect Dis 2016; 62:1338-1347. [PMID: 27001801 PMCID: PMC4872292 DOI: 10.1093/cid/ciw144] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/10/2016] [Indexed: 11/18/2022] Open
Abstract
The first 3 years of biannual ivermectin distribution in Ghana have substantially reduced Onchocerca volvulus infection levels in 10 sentinel communities, but longitudinal analysis indicates that some communities are still consistently responding suboptimally to treatment, with implications for onchocerciasis elimination. Background. Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and suboptimal responses to treatment. We assessed the epidemiological impact of the first 3 years of this strategy and quantified responses to ivermectin over 2 consecutive rounds of treatment in 10 sentinel communities. Methods. We evaluated Onchocerca volvulus community microfilarial intensity and prevalence in persons aged ≥20 years before the first, second, and fifth (or sixth) biannual treatment rounds using skin snip data from 956 participants. We used longitudinal regression modeling to estimate rates of microfilarial repopulation of the skin in a cohort of 217 participants who were followed up over the first 2 rounds of biannual treatment. Results. Biannual treatment has had a positive impact, with substantial reductions in infection intensity after 4 or 5 rounds in most communities. We identified 3 communities—all having been previously recognized as responding suboptimally to ivermectin—with statistically significantly high microfilarial repopulation rates. We did not find any clear association between microfilarial repopulation rate and the number of years of prior intervention, coverage, or the community level of infection. Conclusions. The strategy of biannual ivermectin treatment in Ghana has reduced O. volvulus microfilarial intensity and prevalence, but suboptimal responses to treatment remain evident in a number of previously and consistently implicated communities. Whether increasing the frequency of treatment will be sufficient to meet the World Health Organization's 2020 elimination goals remains uncertain.
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Affiliation(s)
- Kwadwo K Frempong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London
| | - Robert A Cheke
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London.,Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, United Kingdom
| | | | - Ernest Tawiah Gyan
- Council for Scientific and Industrial Research, Water Research Institute, Accra
| | - Ebenezer O Owusu
- Department of Animal Biology and Conservation Science, University of Ghana, Legon
| | - Michael D Wilson
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon
| | - Mark J Taylor
- Department of Parasitology, Liverpool School of Tropical Medicine, United Kingdom
| | | | | | - María-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London
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Eisenbarth A, Achukwi MD, Renz A. Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon. PLoS Negl Trop Dis 2016; 10:e0004392. [PMID: 26926855 PMCID: PMC4771805 DOI: 10.1371/journal.pntd.0004392] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/28/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed. METHODS AND FINDINGS Entomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009-2012: 98, range 47-221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci. CONCLUSIONS/SIGNIFICANCE The high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries.
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Affiliation(s)
- Albert Eisenbarth
- Institute of Evolution and Ecology, Department of Comparative Zoology, University of Tübingen, Tübingen, Germany
- Programme Onchocercoses field station of the University of Tübingen, Ngaoundéré, Cameroon
| | - Mbunkah Daniel Achukwi
- Veterinary research laboratory, Institute of Agricultural Research for Development, Wakwa Regional Centre, Ngaoundéré, Cameroon
| | - Alfons Renz
- Institute of Evolution and Ecology, Department of Comparative Zoology, University of Tübingen, Tübingen, Germany
- * E-mail:
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Botto C, Basañez MG, Escalona M, Villamizar NJ, Noya-Alarcón O, Cortez J, Vivas-Martínez S, Coronel P, Frontado H, Flores J, Graterol B, Camacho O, Tovar Y, Borges D, Morales AL, Ríos D, Guerra F, Margeli H, Rodriguez MA, Unnasch TR, Grillet ME. Evidence of suppression of onchocerciasis transmission in the Venezuelan Amazonian focus. Parasit Vectors 2016; 9:40. [PMID: 26813296 PMCID: PMC4728794 DOI: 10.1186/s13071-016-1313-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/11/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The World Health Organization (WHO) has set goals for onchocerciasis elimination in Latin America by 2015. Most of the six previously endemic countries are attaining this goal by implementing twice a year (and in some foci, quarterly) mass ivermectin (Mectizan®) distribution. Elimination of transmission has been verified in Colombia, Ecuador and Mexico. Challenges remain in the Amazonian focus straddling Venezuela and Brazil, where the disease affects the hard-to-reach Yanomami indigenous population. We provide evidence of suppression of Onchocerca volvulus transmission by Simulium guianense s.l. in 16 previously hyperendemic Yanomami communities in southern Venezuela after 15 years of 6-monthly and 5 years of 3-monthly mass ivermectin treatment. METHODS Baseline and monitoring and evaluation parasitological, ophthalmological, entomological and serological surveys were conducted in selected sentinel and extra-sentinel communities of the focus throughout the implementation of the programme. RESULTS From 2010 to 2012-2015, clinico-parasitological surveys indicate a substantial decrease in skin microfilarial prevalence and intensity of infection; accompanied by no evidence (or very low prevalence and intensity) of ocular microfilariae in the examined population. Of a total of 51,341 S. guianense flies tested by PCR none had L3 infection (heads only). Prevalence of infective flies and seasonal transmission potentials in 2012-2013 were, respectively, under 1% and 20 L3/person/transmission season. Serology in children aged 1-10 years demonstrated that although 26 out of 396 (7%) individuals still had Ov-16 antibodies, only 4/218 (2%) seropositives were aged 1-5 years. CONCLUSIONS We report evidence of recent transmission and morbidity suppression in some communities of the focus representing 75% of the Yanomami population and 70% of all known communities. We conclude that onchocerciasis transmission could be feasibly interrupted in the Venezuelan Amazonian focus.
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Affiliation(s)
- Carlos Botto
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - María-Gloria Basañez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine (St Mary's campus), Imperial College London, London, UK.
| | - Marisela Escalona
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Néstor J Villamizar
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Oscar Noya-Alarcón
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
- Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela.
| | - José Cortez
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Sarai Vivas-Martínez
- Cátedra de Salud Pública. Facultad de Medicina (Escuela Luis Razetti), Universidad Central de Venezuela, Caracas, Venezuela.
| | - Pablo Coronel
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Hortencia Frontado
- Instituto de Altos Estudios "Dr. Arnoldo Gabaldón", Ministerio del Poder Popular para la Salud, Maracay, Estado Aragua, Venezuela.
| | - Jorge Flores
- Instituto Geográfico de Venezuela "Simón Bolívar", Caracas, Venezuela.
| | - Beatriz Graterol
- Instituto Nacional de Investigaciones Agrícolas, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Oneida Camacho
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Yseliam Tovar
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Daniel Borges
- Centro Amazónico de Investigación y Control de Enfermedades Tropicales Servicio Autónomo CAICET, Ministerio del Poder Popular para la Salud, Puerto Ayacucho, Estado Amazonas, Venezuela.
| | - Alba Lucia Morales
- Onchocerciasis Elimination Program for the Americas (OEPA), Guatemala City, Guatemala.
| | - Dalila Ríos
- Onchocerciasis Elimination Program for the Americas (OEPA), Guatemala City, Guatemala.
| | - Francisco Guerra
- Instituto Geográfico de Venezuela "Simón Bolívar", Caracas, Venezuela.
| | - Héctor Margeli
- Onchocerciasis Elimination Program for the Americas (OEPA), Guatemala City, Guatemala.
| | | | - Thomas R Unnasch
- Department of Global Health, University of South Florida, Tampa, FL, USA.
| | - María Eugenia Grillet
- Laboratorio de Biología de Vectores y Parásitos, Instituto de Zoología y Ecología Tropical, Facultad de Ciencias, Universidad Central de Venezuela, Apartado Postal 47072, Caracas, 1041-A, Venezuela.
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Diagnostic Tools for Onchocerciasis Elimination Programs. Trends Parasitol 2015; 31:571-582. [PMID: 26458784 DOI: 10.1016/j.pt.2015.06.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 11/24/2022]
Abstract
Onchocerciasis (river blindness) is a major public health problem in sub-Saharan Africa. Major disease-control programs have greatly reduced both disease and infection prevalence by mass distribution of donated ivermectin. Recent studies have shown that local elimination was achieved in some areas following many years of ivermectin. The global health community has recently decided to build on these successes with a new program that aims to eliminate onchocerciasis. Diagnostic tests that were useful for identifying priority areas for disease prevention may not be adequate tools for elimination programs. This paper reviews available and emerging diagnostic tests for onchocerciasis and considers how they might be best employed during different stages of onchocerciasis elimination programs.
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Rodríguez-Pérez MA, Fernández-Santos NA, Orozco-Algarra ME, Rodríguez-Atanacio JA, Domínguez-Vázquez A, Rodríguez-Morales KB, Real-Najarro O, Prado-Velasco FG, Cupp EW, Richards FO, Hassan HK, González-Roldán JF, Kuri-Morales PA, Unnasch TR. Elimination of Onchocerciasis from Mexico. PLoS Negl Trop Dis 2015; 9:e0003922. [PMID: 26161558 PMCID: PMC4498594 DOI: 10.1371/journal.pntd.0003922] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 06/17/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mexico is one of the six countries formerly endemic for onchocerciasis in Latin America. Transmission has been interrupted in the three endemic foci of that country and mass drug distribution has ceased. Three years after mass drug distribution ended, post-treatment surveillance (PTS) surveys were undertaken which employed entomological indicators to check for transmission recrudescence. METHODOLOGY/PRINCIPAL FINDINGS In-depth entomologic assessments were performed in 18 communities in the three endemic foci of Mexico. None of the 108,212 Simulium ochraceum s.l. collected from the three foci were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in a maximum upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.035/2,000 flies examined. This is an order of magnitude below the threshold of a 95%-ULCI of less than one infective fly per 2,000 flies tested, the current entomological criterion for interruption of transmission developed by the international community. The point estimate of seasonal transmission potential (STP) was zero, and the upper bound of the 95% confidence interval for the STP ranged from 1.2 to 1.7 L3/person/season in the different foci. This value is below all previous estimates for the minimum transmission potential required to maintain the parasite population. CONCLUSIONS/SIGNIFICANCE The results from the in-depth entomological post treatment surveillance surveys strongly suggest that transmission has not resumed in the three foci of Mexico during the three years since the last distribution of ivermectin occurred; it was concluded that transmission remains undetectable without intervention, and Onchocerca volvulus has been eliminated from Mexico.
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Affiliation(s)
| | - Nadia A. Fernández-Santos
- Dirección General de Programas Preventivos, Centro Nacional de Programas Preventivos y Control de Enfermedades, Secretaría de Salud, Colonia Escandón, Delegación Miguel Hidalgo, Mexico City, México
| | - María E. Orozco-Algarra
- Dirección General de Programas Preventivos, Centro Nacional de Programas Preventivos y Control de Enfermedades, Secretaría de Salud, Colonia Escandón, Delegación Miguel Hidalgo, Mexico City, México
| | - José A. Rodríguez-Atanacio
- Dirección General de Programas Preventivos, Centro Nacional de Programas Preventivos y Control de Enfermedades, Secretaría de Salud, Colonia Escandón, Delegación Miguel Hidalgo, Mexico City, México
| | | | | | | | - Francisco G. Prado-Velasco
- Programa de Eliminación de la Oncocercosis en Chiapas, Departamento de Prevención y Control de Enfermedades Transmitidas por Vector, Secretaría de Salud Unidad Administrativa, Tuxtla Gutiérrez, Chiapas, México
| | - Eddie W. Cupp
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Frank O. Richards
- River Blindness Program, Carter Center, Atlanta, Georgia, United States of America
| | - Hassan K. Hassan
- Global Health Infectious Disease Research Program, Department of Global Health,University of South Florida, Tampa, Florida, United States of America
| | - Jesús F. González-Roldán
- Dirección General de Programas Preventivos, Centro Nacional de Programas Preventivos y Control de Enfermedades, Secretaría de Salud, Colonia Escandón, Delegación Miguel Hidalgo, Mexico City, México
| | - Pablo A. Kuri-Morales
- Subsecretaría de Prevención y Promoción de la Salud, Secretaría de Salud, Colonia Juárez, Delegación Cuauhtémoc, México, D.F., México
| | - Thomas R. Unnasch
- Global Health Infectious Disease Research Program, Department of Global Health,University of South Florida, Tampa, Florida, United States of America
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Katabarwa MN, Habomugisha P, Eyamba A, Byamukama E, Nwane P, Arinaitwe A, Musigire J, Tushemereirwe R, Khainza A. Community-directed interventions are practical and effective in low-resource communities: experience of ivermectin treatment for onchocerciasis control in Cameroon and Uganda, 2004-2010. Int Health 2015; 8:116-23. [PMID: 26152231 DOI: 10.1093/inthealth/ihv038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 04/20/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The community-directed intervention (CDI) approach has improved treatment coverage in onchocerciasis-affected communities. However, there is still a lot to learn. This study assessed its performance and highlighted the lessons learnt so far. METHODS Representative samples of households were selected from Cameroon and Uganda program areas through multi-stage random sampling. An adult male and female from every selected household were interviewed separately on their involvement in CDI activities every year between 2004 and 2010. Community health workers (CHWs) were interviewed and treatment records reviewed to determine whether 90% treatment coverage was attained within 2 weeks. Records related to training of CHWs and their supervisors were analyzed. RESULTS Decision making decreased for community leaders and health workers, while it increased for community members. The proportion of CHWs attaining 90% treatment coverage within 2 weeks improved as their demand for monetary incentives, and number of persons they served, reduced. The number of CHWs supervised by a community supervisor remained low, but increased for the health workers. The cost of training a CHW and a community supervisor reduced to about US$1 and US$4.8, respectively. CONCLUSIONS The CDI approach was effective, culturally appropriate and probably less costly in delivering health services in low-resource communities.
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Affiliation(s)
| | | | | | | | | | - Alex Arinaitwe
- Uganda Management Institute, P.O. Box 20131, Kampala, Uganda
| | - Julius Musigire
- Action for Youth and Women Network, PO Box 16144, Kampala, Uganda
| | - Ruth Tushemereirwe
- Makerere University, School of Social Sciences, P.O Box 7062, Kampala, Uganda
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Dunn C, Callahan K, Katabarwa M, Richards F, Hopkins D, Withers PC, Buyon LE, McFarland D. The Contributions of Onchocerciasis Control and Elimination Programs toward the Achievement of the Millennium Development Goals. PLoS Negl Trop Dis 2015; 9:e0003703. [PMID: 25996946 PMCID: PMC4440802 DOI: 10.1371/journal.pntd.0003703] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In 2000, 189 member states of the United Nations (UN) developed a plan for peace and development, which resulted in eight actionable goals known as the Millennium Development Goals (MDGs). Since their inception, the MDGs have been considered the international standard for measuring development progress and have provided a blueprint for global health policy and programming. However, emphasis upon the achievement of priority benchmarks around the "big three" diseases--namely HIV, tuberculosis (TB), and malaria--has influenced global health entities to disproportionately allocate resources. Meanwhile, several tropical diseases that almost exclusively impact the poorest of the poor continue to be neglected, despite the existence of cost-effective and feasible methods of control or elimination. One such Neglected Tropical Disease (NTD), onchocerciasis, more commonly known as river blindness, is a debilitating and stigmatizing disease primarily affecting individuals living in remote and impoverished areas. Onchocerciasis control is considered to be one of the most successful and cost-effective public health campaigns ever launched. In addition to improving the health and well-being of millions of individuals, these programs also lead to improvements in education, agricultural production, and economic development in affected communities. Perhaps most pertinent to the global health community, though, is the demonstrated effectiveness of facilitating community engagement by allowing communities considerable ownership with regard to drug delivery. This paper reviews the contributions that such concentrated efforts to control and eliminate onchocerciasis make to achieving select MDGs. The authors hope to draw the attention of public policymakers and global health funders to the importance of the struggle against onchocerciasis as a model for community-directed interventions to advance health and development, and to advocate for NTDs inclusion in the post 2015 agenda.
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Affiliation(s)
- Caitlin Dunn
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Kelly Callahan
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Moses Katabarwa
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Frank Richards
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Donald Hopkins
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - P. Craig Withers
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Lucas E. Buyon
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
- College of Arts and Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Deborah McFarland
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
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Katabarwa M, Richards F. Twice-yearly ivermectin for onchocerciasis: the time is now. THE LANCET. INFECTIOUS DISEASES 2014; 14:373-4. [PMID: 24758997 DOI: 10.1016/s1473-3099(14)70732-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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