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Nikièma AS, Koala L, Unnasch TR, Diendéré J, Compaoré J, Ouédraogo MW, Kafando CM, Bakajika D, Bougouma C, Faye B, Traoré S, Dabiré RK. Field sensitivity and specificity of the SD BIOLINE onchocerciasis IgG4 Rapid Diagnostic Test in children <10 years old from endemic areas in Burkina Faso. Parasite Epidemiol Control 2024; 25:e00352. [PMID: 38708128 PMCID: PMC11066673 DOI: 10.1016/j.parepi.2024.e00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/04/2024] [Accepted: 04/21/2024] [Indexed: 05/07/2024] Open
Abstract
Skin biopsies (Skin snips) have historically been the gold standard for the diagnosis of onchocerciasis. However, in low prevalence areas and in areas with successful ivermectin mass drug administration (MDA) programs, skin snips are not sensitive enough to decide when to stop MDA; thus, serological diagnostic tools have been recommended for this purpose. This study assessed the sensitivity and specificity of the Ov16 Rapid Diagnostic Test (SD BIOLINE Onchocerciasis RDT) compared to skin snip in endemic areas undergoing ivermectin mass distribution using Community Directed Treatment with Ivermectin (CDTI) strategy. A cross-sectional study was conducted between September and November 2016 in five endemic villages in the Cascades region in Burkina Faso. Children aged 2 to 9-years were examined during the impact epidemiological survey using both the skin snip and Ov16 Rapid Diagnostic Test. The Ov16 Rapid Diagnostic Test sensitivity and specificity were determined with reference to the skin biopsy. Skin snip positivity was 1.25% in this population, while seroprevalence was 6.5%. When compared to the skin snip as the gold standard, the sensitivity of the Ov16 Rapid Diagnostic Test was 60% and the specificity 94%. When the Ov16 Rapid Diagnostic Test was considered as the gold standard, the skin snip exhibited a sensitivity of 11.5% and a specificity of 99.5%. These results are similar to other studies comparing the performance of the Ov16 ELISA to skin snips, suggesting that the Ov16 RDT may be a useful tool for ivermectin STOP MDA and post transmission surveys, assuming that the prevalence of infection is low or close to zero, and the Ov16 RDT detected also pre patent infections.
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Affiliation(s)
- Achille Sindimbasba Nikièma
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI), Bobo-Dioulasso, Burkina Faso
- Université Cheikh Anta Diop (UCAD), Dakar, Sénégal
| | - Lassane Koala
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI), Bobo-Dioulasso, Burkina Faso
| | - Thomas R. Unnasch
- Center for Global Infectious Disease Research, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Jeoffray Diendéré
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI), Bobo-Dioulasso, Burkina Faso
| | - Justin Compaoré
- Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ministère de la Santé et de l'Hygiène Publique, Ouagadougou, Burkina Faso
| | - Mathias W. Ouédraogo
- Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ministère de la Santé et de l'Hygiène Publique, Ouagadougou, Burkina Faso
| | - Claude Montant Kafando
- Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ministère de la Santé et de l'Hygiène Publique, Ouagadougou, Burkina Faso
| | - Didier Bakajika
- Expanded Special Project for Elimination of Neglected Tropical Diseases, ESPEN, Regional Office for Africa, World Health Organization, Brazzaville, Congo
| | - Clarisse Bougouma
- Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ministère de la Santé et de l'Hygiène Publique, Ouagadougou, Burkina Faso
| | - Babacar Faye
- Université Cheikh Anta Diop (UCAD), Dakar, Sénégal
| | - Soungalo Traoré
- Direction de la Protection de la Santé de la Population, Programme National de Lutte Contre les Maladies Tropicales Négligées, Ministère de la Santé et de l'Hygiène Publique, Ouagadougou, Burkina Faso
| | - Roch Kounbobr Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation (MESRI), Bobo-Dioulasso, Burkina Faso
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Kargbo-Labour I, Bah MS, Melchers NVSV, Conteh A, Redwood-Sawyerr V, Stolk WA, Paye J, Sonnie M, Veinoglou A, Koroma JB, Hodges MH, Weaver AM, Zhang Y. Impact assessment of onchocerciasis through lymphatic filariasis transmission assessment surveys using Ov-16 rapid diagnostic tests in Sierra Leone. Parasit Vectors 2024; 17:121. [PMID: 38468307 PMCID: PMC10926616 DOI: 10.1186/s13071-024-06198-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/15/2024] [Indexed: 03/13/2024] Open
Abstract
BACKGROUND Onchocerciasis is endemic in 14 of Sierra Leone's 16 districts with high prevalence (47-88.5%) according to skin snips at baseline. After 11 rounds of mass treatment with ivermectin with good coverage, an impact assessment was conducted in 2017 to assess the progress towards eliminating onchocerciasis in the country. METHODS A cluster survey was conducted, either integrated with lymphatic filariasis (LF) transmission assessment survey (TAS) or standalone with the LF TAS sampling strategy in 12 (now 14) endemic districts. Finger prick blood samples of randomly selected children in Grades 1-4 were tested in the field using SD Bioline Onchocerciasis IgG4 rapid tests. RESULTS In total, 17,402 children aged 4-19 years in 177 schools were tested, and data from 17,364 children aged 4-14 years (14,230 children aged 5-9 years) were analyzed. Three hundred forty-six children were confirmed positive for Ov-16 IgG4 antibodies, a prevalence of 2.0% (95% CI 1.8-2.2%) in children aged 4-14 years with prevalence increasing with age. Prevalence in boys (2.4%; 95% CI 2.1-2.7%) was higher than in girls (1.6%; 95% CI 1.4-1.9%). There was a trend of continued reduction from baseline to 2010. Using data from children aged 5-9 years, overall prevalence was 1.7% (95% CI 1.5-1.9%). The site prevalence ranged from 0 to 33.3% (median prevalence = 0.0%): < 2% in 127 schools, 2 to < 5% in 34 schools and ≥ 5% in 16 schools. There was a significant difference in average prevalence between districts. Using spatial analysis, the Ov-16 IgG4 antibody prevalence was predicted to be < 2% in coastal areas and in large parts of Koinadugu, Bombali and Tonkolili Districts, while high prevalence (> 5%) was predicted in some focal areas, centered in Karene, Kailahun and Moyamba/Tonkolili. CONCLUSIONS Low Ov-16 IgG4 antibody prevalence was shown in most areas across Sierra Leone. In particular, low seroprevalence in children aged 5-9 years suggests that the infection was reduced to a low level after 11 rounds of treatment intervention. Sierra Leone has made major progress towards elimination of onchocerciasis. However, attention must be paid to those high prevalence focal areas.
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Affiliation(s)
- Ibrahim Kargbo-Labour
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Natalie V S Vinkeles Melchers
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Social Sciences, Health and Society, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Abdulai Conteh
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jusufu Paye
- Helen Keller International, Freetown, Sierra Leone
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Otiti-Sengeri J, Sube KLL, Siewe Fodjo JN, Otabil KB, Colebunders R. Chorioretinitis among Immigrant and Travellers. Comment on Mansour et al. Presumed Onchocerciasis Chorioretinitis Spilling over into North America, Europe and Middle East. Diagnostics 2023, 13, 3626. Diagnostics (Basel) 2024; 14:478. [PMID: 38472950 DOI: 10.3390/diagnostics14050478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/08/2024] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
We read, with interest, the paper by Mansour et al [...].
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Affiliation(s)
| | | | | | - Kenneth Bentum Otabil
- Department of Biological Science, University of Energy and Natural Resources, Sunyani P.O. Box 214, Ghana
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
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Otabil KB, Basáñez MG, Ankrah B, Opoku SA, Kyei DO, Hagan R, Ababio R, Bart-Plange EJ, Babae TN, Kudzordzi PC, Darko VA, Bamfo JG, Ameyaw J, Raji AS, Hadermann A, Schallig HDFH, Colebunders R. Persistence of onchocerciasis and associated dermatologic and ophthalmic pathologies after 27 years of ivermectin mass drug administration in the middle belt of Ghana. Trop Med Int Health 2023; 28:844-854. [PMID: 37846505 DOI: 10.1111/tmi.13937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
OBJECTIVES There is a pressing need to regularly evaluate the progress of onchocerciasis elimination programmes to timely identify and mitigate potential risks hindering the reaching of the 2030 targets proposed by the World Health Organization (WHO) in its roadmap on neglected tropical diseases (NTDs). We determined the prevalence of onchocerciasis and associated dermatological and ophthalmological manifestations in six endemic communities in the Bono Region of Ghana after 27 years of ivermectin mass treatment. METHODS In a cross-sectional study, 564 participants aged ≥5 years were enrolled (49.1% females), with a median age of 26 (range: 5-89) years. In 54% and 47%, skin-snip microscopy and Ov16 rapid diagnostic tests were performed, respectively. Skin disease was determined using the WHO Skin NTD App. Visual function assessments included tests of visual acuity. RESULTS The overall microfilarial prevalence was 12.5% (38/305) and Ov16 seroprevalence was 24.2% (64/265). Severe itching was recorded in 24.3%, acute papular onchodermatitis in 52.8%, chronic papular onchodermatitis in 12.5%, lichenified onchodermatitis in 0.7%, skin atrophy in 11.3%, depigmentation in 1.7% and palpable nodules in 5.3%. Of the 301 persons in which visual acuity was examined, 17% were visually impaired and 5.3% were blind and 47.3% presented with cataract. Chronic papular onchodermatitis, lichenified onchodermatitis, depigmentation and visual impairment were significantly associated with the presence of skin microfilariae and Ov16 seropositivity. CONCLUSIONS The persistence of Onchocerca volvulus infection and onchocerciasis-associated dermatological and ophthalmological pathologies after prolonged treatment is of concern. There is a need to include morbidity management in onchocerciasis elimination programmes and understand better patterns of treatment coverage, adherence and actual intake of ivermectin.
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Affiliation(s)
- Kenneth Bentum Otabil
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
- Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
- Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis (MRC GIDA), and London Centre for Neglected Tropical Disease Research, School of Public Health, Imperial College London, London, UK
| | - Blessing Ankrah
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Stephen Agyemang Opoku
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Dennis Ofori Kyei
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Rhoda Hagan
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Richmond Ababio
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Emmanuel John Bart-Plange
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Theophilus Nti Babae
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Prince-Charles Kudzordzi
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Vera Achiaa Darko
- Consortium for Neglected Tropical Diseases and One Health, Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
- STU Clinic, Sunyani Technical University, Sunyani, Bono Region, Ghana
| | | | | | - Abdul Sakibu Raji
- Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Sunyani, Bono Region, Ghana
| | - Amber Hadermann
- Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Henk D F H Schallig
- Department of Medical Microbiology, Experimental Parasitology Unit, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, Amsterdam, The Netherlands
| | - Robert Colebunders
- Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Louart S, Hedible GB, Ridde V. Assessing the acceptability of technological health innovations in sub-Saharan Africa: a scoping review and a best fit framework synthesis. BMC Health Serv Res 2023; 23:930. [PMID: 37649024 PMCID: PMC10469465 DOI: 10.1186/s12913-023-09897-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/10/2023] [Indexed: 09/01/2023] Open
Abstract
Acceptability is a key concept used to analyze the introduction of a health innovation in a specific setting. However, there seems to be a lack of clarity in this notion, both conceptually and practically. In low and middle-income countries, programs to support the diffusion of new technological tools are multiplying. They face challenges and difficulties that need to be understood with an in-depth analysis of the acceptability of these innovations. We performed a scoping review to explore the theories, methods and conceptual frameworks that have been used to measure and understand the acceptability of technological health innovations in sub-Saharan Africa. The review confirmed the lack of common definitions, conceptualizations and practical tools addressing the acceptability of health innovations. To synthesize and combine evidence, both theoretically and empirically, we then used the "best fit framework synthesis" method. Based on five conceptual and theoretical frameworks from scientific literature and evidence from 33 empirical studies, we built a conceptual framework in order to understand the acceptability of technological health innovations. This framework comprises 6 determinants (compatibility, social influence, personal emotions, perceived disadvantages, perceived advantages and perceived complexity) and two moderating factors (intervention and context). This knowledge synthesis work has also enabled us to propose a chronology of the different stages of acceptability.
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Affiliation(s)
- Sarah Louart
- Univ. Lille, CNRS, UMR 8019 - CLERSE - Centre Lillois d'Etudes Et de Recherches Sociologiques Et Economiques, 59000, Lille, France.
- ALIMA, the Alliance for International Medical Action, Dakar, Senegal.
| | | | - Valéry Ridde
- Université Paris Cité, IRD, INSERM, Ceped, 75006, Paris, France
- Institut de Santé Et Développement, Université Cheikh Anta Diop, Dakar, Sénégal
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Murphy E, Togbevi IC, Ibikounlé M, Avokpaho EFGA, Walson JL, Means AR. Soil-transmitted helminth surveillance in Benin: A mixed-methods analysis of factors influencing non-participation in longitudinal surveillance activities. PLoS Negl Trop Dis 2023; 17:e0010984. [PMID: 36626399 PMCID: PMC9831304 DOI: 10.1371/journal.pntd.0010984] [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: 08/15/2022] [Accepted: 11/25/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Despite the significant success of deworming programs in reducing morbidity due to soil-transmitted helminth (STH) infections globally, efforts to achieve elimination of STH as a public health problem or to potentially interrupt transmission will require improving and intensifying surveillance. However, non-participation in surveillance threatens the ability of programs to adequately monitor program status and limited research has been conducted to investigate drivers of non-participation in stool-based surveillance. METHODOLOGY/PRINCIPAL FINDINGS This mixed-methods exploratory sequential study took place in Comé, Benin in association with the DeWorm3 Project. Six focus group discussions were conducted with individuals invited to participate in annual DeWorm3 stool surveillance. Thematic analysis was used to identify facilitators and barriers to participation and inform the quantitative analysis. A mixed-effects logistic regression model was built using baseline DeWorm3 survey data to identify factors associated with non-participation. Qualitative and quantitative findings were merged for interpretation. Among the 7,039 individuals invited to participate in baseline stool surveillance, the refusal rate was 8.1%. Qualitative themes included: community members weighing community-level benefits against individual-level risks, circulating rumors about misuse of stool samples, interpersonal communication with field agents, and cultural norms around handling adult feces. The quantitative analysis demonstrated that adults were significantly less likely to provide a stool sample than school-aged children (OR:0.69, 95%CI: 0.55-0.88), a finding that converged with the qualitative results. Individuals from areas in the highest quartile of population density were more likely to refuse to participate (OR:1.71, 95%CI:1.16-2.52). Several variables linked to community-affinity aligned with qualitative results; residing mainly in the community (OR:0.36, 95%CI:0.20-0.66) and having lived in the community for more than 10 years (OR:0.82, 95%CI:0.54-1.25) decreased likelihood of refusal. CONCLUSIONS/SIGNIFICANCE Optimizing STH surveillance will require that programs reimagine STH surveillance activities to address community concerns and ensure that no subpopulations are inadvertently excluded from surveillance data.
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Affiliation(s)
- Emma Murphy
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- * E-mail: (EM); (ICT)
| | | | - Moudachirou Ibikounlé
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Bénin
- Centre de Recherche pour la lutte contre les Maladies Infectieuses Tropicales (CReMIT/TIDRC), Université d’Abomey-Calavi, Bénin
| | | | - Judd L. Walson
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
| | - Arianna Rubin Means
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
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Otiti-Sengeri J, Omaido BA, Bhwana D, Nakanjako D, Missiru M, Muwonge M, Amaral LJ, Mmbando BP, Colebunders R. High Prevalence of Glaucoma among Patients in an Onchocerciasis Endemic Area (Mahenge, Tanzania). Pathogens 2022; 11:pathogens11091046. [PMID: 36145478 PMCID: PMC9501165 DOI: 10.3390/pathogens11091046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 11/22/2022] Open
Abstract
Onchocerciasis is known to cause skin lesions and blindness, but there is also epidemiological evidence that onchocerciasis is associated with epilepsy, including nodding syndrome. We carried out ocular exams in persons with epilepsy in Mahenge, an onchocerciasis endemic area with a high prevalence of epilepsy in Tanzania. We recruited 278 consecutive persons with epilepsy attending the epilepsy clinic at Mahenge hospital and satellite clinics in rural villages. They underwent a general physical and a detailed ocular examination and were tested for onchocerciasis Ov16 IgG4 antibodies. Glaucoma was defined by a raised intraocular pressure above 21 mmHg with evidence of typical glaucomatous disc changes in one or both eyes. Among the 278 participants, median age 27 (IQR 21–38) years, 55.4% were female; 151/210 (71.9%) (95% CI: 65.3–77.9) were Ov16 positive. The most frequent ophthalmic lesions were glaucoma (33.1%), vitreous opacities (6.5%) and cataracts (2.9%). In multivariate analysis, glaucoma (adjusted IRR = 1.46; 95% CI: 1.24–1.70) and age (adjusted IRR = 1.01; 95% CI: 1.01–1.02) were significantly associated with onchocerciasis. In conclusion, a high prevalence of glaucoma was observed among Ov16 positive persons with epilepsy. Persons with epilepsy with O. volvulus infection should undergo screening for glaucoma to prevent one of the causes of preventable blindness.
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Affiliation(s)
- Juliet Otiti-Sengeri
- Department of Ophthalmology, College of Health Sciences, Makerere University, Kampala P.O. Box 7072, Uganda
- Correspondence: ; Tel.: +256-772381162; Fax: +256-41255962
| | - Blair Andrew Omaido
- Department of Ophthalmology, College of Health Sciences, Makerere University, Kampala P.O. Box 7072, Uganda
| | - Dan Bhwana
- National Institute for Medical Research, Tanga Centre, Tanga P.O. Box 5004, Tanzania
| | - Damalie Nakanjako
- Department of Internal Medicine, College of Health Sciences, Makerere University, Kampala P.O. Box 7072, Uganda
| | - Malik Missiru
- Department of Ophthalmology, Mahenge District Hospital, Mahenge P.O. Box 4, Tanzania
| | - Musa Muwonge
- School of Medicine, Soroti University, Soroti P.O. Box 690, Uganda
| | - Luis-Jorge Amaral
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610 Antwerp, Belgium
| | - Bruno P. Mmbando
- National Institute for Medical Research, Tanga Centre, Tanga P.O. Box 5004, Tanzania
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610 Antwerp, Belgium
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Yengo BN, Shintouo CM, Hotterbeekx A, Yaah NE, Shey RA, Quanico J, Baggerman G, Ayong L, Vanhamme L, Njemini R, Souopgui J, Colebunders R, Ghogomu SM. Immunoinformatics Design and Assessment of a Multiepitope Antigen (OvMCBL02) for Onchocerciasis Diagnosis and Monitoring. Diagnostics (Basel) 2022; 12:diagnostics12061440. [PMID: 35741250 PMCID: PMC9221995 DOI: 10.3390/diagnostics12061440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/28/2022] [Accepted: 06/09/2022] [Indexed: 11/23/2022] Open
Abstract
Onchocerciasis is a Neglected Tropical Disease that has a significant socioeconomic impact, especially in Sub-Saharan Africa. Numerous reports indicate that the Expanded Special Project for the Elimination of Neglected Tropical Diseases needs novel diagnostic tools before achieving its goal of successful elimination of onchocerciasis in Africa. The current diagnostic tests are either invasive, insensitive, or not applicable in the field and about 25% of persons infected cannot mount immune responses against the single antigen used in the only approved Ov-16 serological test. In the quest to identify novel biomarkers that can be used to certify that a patient is free from the disease, evaluate the progress of elimination programmes, and conduct post elimination surveillances, mass spectrometric analysis of Onchocerca volvulus crude extract revealed that 1392 proteins are expressed in the adult and microfilariae stages of the parasite. Computational analysis predicted six of the proteins as O. volvulus potential diagnostic targets. Linear B-epitopes were predicted from the six proteins and used to construct a multiepitope antigen (OvMCBL02). Serological analysis revealed that the OvMCBL02 test significantly differentiated between serum samples of onchocerciasis patients from the Kombone Health Area in the South West Region of Cameroon (n = 63) and control serum samples from Rwanda (n = 29) and Europe (n = 26) as well as between serum samples from the onchocerciasis hyperendemic region of Kombone Health Area (n = 63) and the hypoendemic region of Bandjoun Health District (n = 54). Interestingly, the test did not cross-react with serum samples from patients suffering from related nematode infections, thereby suggesting that further characterization of the OvMCBL02 multiepitope antigen will render it an additional member of the diagnostic toolbox for the elimination of onchocerciasis.
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Affiliation(s)
- Bernis Neneyoh Yengo
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (B.N.Y.); (C.M.S.); (N.E.Y.); (R.A.S.)
| | - Cabirou Mounchili Shintouo
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (B.N.Y.); (C.M.S.); (N.E.Y.); (R.A.S.)
- Department of Gerontology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium;
- Frailty in Ageing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - An Hotterbeekx
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium; (A.H.); (R.C.)
- Molecular Pathology Group, Laboratory of Cell biology and Histology, University of Antwerp, 2610 Antwerp, Belgium
| | - Ntang Emmaculate Yaah
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (B.N.Y.); (C.M.S.); (N.E.Y.); (R.A.S.)
| | - Robert Adamu Shey
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (B.N.Y.); (C.M.S.); (N.E.Y.); (R.A.S.)
| | - Jusal Quanico
- Center for Proteomics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium; (J.Q.); (G.B.)
| | - Geert Baggerman
- Center for Proteomics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium; (J.Q.); (G.B.)
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé P.O. Box 1274, Cameroon;
| | - Luc Vanhamme
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Gosselies Campus, Université Libre de Bruxelles, 1070 Brussels, Belgium; (L.V.); (J.S.)
| | - Rose Njemini
- Department of Gerontology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium;
- Frailty in Ageing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Jacob Souopgui
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Gosselies Campus, Université Libre de Bruxelles, 1070 Brussels, Belgium; (L.V.); (J.S.)
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium; (A.H.); (R.C.)
| | - Stephen Mbigha Ghogomu
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea P.O. Box 63, Cameroon; (B.N.Y.); (C.M.S.); (N.E.Y.); (R.A.S.)
- Correspondence: ; Tel.: +237-6-7845-5646
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Dusabimana A, Siewe Fodjo JN, Ndahura MM, Mmbando BP, Jada SR, Boven A, De Smet E, Ukety T, Njamnshi AK, Laudisoit A, Abrams S, Colebunders R. Surveillance for Onchocerciasis-Associated Epilepsy and OV16 IgG4 Testing of Children 6–10 Years Old Should Be Used to Identify Areas Where Onchocerciasis Elimination Programs Need Strengthening. Pathogens 2022; 11:pathogens11030281. [PMID: 35335605 PMCID: PMC8949980 DOI: 10.3390/pathogens11030281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 01/27/2023] Open
Abstract
To eliminate onchocerciasis-associated morbidity, it is important to identify areas where there is still high ongoing Onchocerca volvulus transmission. Between 2015 and 2021, door-to-door surveys were conducted in onchocerciasis-endemic villages in Cameroon, the Democratic Republic of Congo (DRC), Nigeria, South Sudan, and Tanzania to determine epilepsy prevalence and incidence, type of epilepsy and ivermectin therapeutic coverage. Moreover, children aged between six and 10 years were tested for anti-Onchocerca antibodies using the Ov16 IgG4 rapid diagnostic test (RDT). A mixed-effect binary logistic regression analysis was used to assess significantly associated variables of Ov16 antibody seroprevalence. A high prevalence and incidence of epilepsy was found to be associated with a high Ov16 antibody seroprevalence among 6–10-year-old children, except in the Logo health zone, DRC. The low Ov16 antibody seroprevalence among young children in the Logo health zone, despite a high prevalence of epilepsy, may be explained by a recent decrease in O. volvulus transmission because of a decline in the Simulium vector population as a result of deforestation. In the Central African Republic, a new focus of O. volvulus transmission was detected based on the high Ov16 IgG4 seropositivity among children and the detecting of nodding syndrome cases, a phenotypic form of onchocerciasis-associated epilepsy (OAE). In conclusion, Ov16 IgG4 RDT testing of 6–10-year-old children is a cheap and rapid method to determine the level of ongoing O. volvulus transmission and to assess, together with surveillance for OAE, the performance of onchocerciasis elimination programs.
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Affiliation(s)
- Alfred Dusabimana
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
| | - Joseph Nelson Siewe Fodjo
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
- Brain Research Africa Initiative (BRAIN), Yaoundé P.O. Box 25625, Cameroon;
| | - Michel Mandro Ndahura
- Provincial Health Division Ituri, Ministry of Health, Bunia P.O. Box 57, Ituri, Democratic Republic of the Congo;
| | - Bruno P. Mmbando
- National Institute for Medical Research, Tanga Centre, Tanga P.O. Box 5004, Tanzania;
| | | | - Annelies Boven
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
| | - Eric De Smet
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
| | - Tony Ukety
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Ituri, Democratic Republic of the Congo;
| | - Alfred K. Njamnshi
- Brain Research Africa Initiative (BRAIN), Yaoundé P.O. Box 25625, Cameroon;
- Neuroscience Laboratory, Faculty of Medicine and Biomedical Sciences, The University of Yaoundé I, Yaoundé P.O. Box 25625, Cameroon
- Neurology Department, Yaoundé Central Hospital, Yaoundé P.O. Box 25625, Cameroon
| | - Anne Laudisoit
- EcoHealth Alliance, 520 8th Ave Ste. 1200, New York, NY 10018, USA;
- Evolutionary Ecology Group (EVECO), University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Steven Abrams
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
- Interuniversity Institute for Biostatistics and statistical Bioinformatics, Data Science Institute, UHasselt, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Doornstraat 331, 2610 Antwerp, Belgium; (A.D.); (J.N.S.F.); (A.B.); (E.D.S.); (S.A.)
- Correspondence:
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Albert H, Sartorius B, Bessell PR, de Souza DK, Rupani S, Gonzalez K, Kayembe S, Ndung’u J, Pullan R, Makana DP, de Almeida MCC, Uvon NA. Developing Strategies for Onchocerciasis Elimination Mapping and Surveillance Through The Diagnostic Network Optimization Approach. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.707752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundOnchocerciasis (river blindness) is a filarial disease targeted for elimination of transmission. However, challenges exist to the implementation of effective diagnostic and surveillance strategies at various stages of elimination programs. To address these challenges, we used a network data analytics approach to identify optimal diagnostic scenarios for onchocerciasis elimination mapping (OEM).MethodsThe diagnostic network optimization (DNO) method was used to model the implementation of the old Ov16 rapid diagnostic test (RDT) and of new RDTs in development for OEM under different testing strategy scenarios with varying testing locations, test performance and disease prevalence. Environmental suitability scores (ESS) based on machine learning algorithms were developed to identify areas at risk of transmission and used to select sites for OEM in Bandundu region in the Democratic Republic of Congo (DRC) and Uige province in Angola. Test sensitivity and specificity ranges were obtained from the literature for the existing RDT, and from characteristics defined in the target product profile for the new RDTs. Sourcing and transportation policies were defined, and costing information was obtained from onchocerciasis programs. Various scenarios were created to test various state configurations. The actual demand scenarios represented the disease prevalence at IUs according to the ESS, while the counterfactual scenarios (conducted only in the DRC) are based on adapted prevalence estimates to generate prevalence close to the statistical decision thresholds (5% and 2%), to account for variability in field observations. The number of correctly classified implementation units (IUs) per scenario were estimated and key cost drivers were identified.ResultsIn both Bandundu and Uige, the sites selected based on ESS had high predicted onchocerciasis prevalence >10%. Thus, in the actual demand scenarios in both Bandundu and Uige, the old Ov16 RDT correctly classified all 13 and 11 IUs, respectively, as requiring CDTi. In the counterfactual scenarios in Bandundu, the new RDTs with higher specificity correctly classified IUs more cost effectively. The new RDT with highest specificity (99.8%) correctly classified all 13 IUs. However, very high specificity (e.g., 99.8%) when coupled with imperfect sensitivity, can result in many false negative results (missing decisions to start MDA) at the 5% statistical decision threshold (the decision rule to start MDA). This effect can be negated by reducing the statistical decision threshold to 2%. Across all scenarios, the need for second stage sampling significantly drove program costs upwards. The best performing testing strategies with new RDTs were more expensive than testing with existing tests due to need for second stage sampling, but this was offset by the cost of incorrect classification of IUs.ConclusionThe new RDTs modelled added most value in areas with variable disease prevalence, with most benefit in IUs that are near the statistical decision thresholds. Based on the evaluations in this study, DNO could be used to guide the development of new RDTs based on defined sensitivities and specificities. While test sensitivity is a minor driver of whether an IU is identified as positive, higher specificities are essential. Further, these models could be used to explore the development and optimization of new tools for other neglected tropical diseases.
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Wang Y, Ma A, Liu XL, Eamsobhana P, Gan XX. Evaluation of Rapid IgG4 Test for Diagnosis of Gnathostomiasis. THE KOREAN JOURNAL OF PARASITOLOGY 2021; 59:257-263. [PMID: 34218597 PMCID: PMC8255487 DOI: 10.3347/kjp.2021.59.3.257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 02/23/2021] [Indexed: 12/01/2022]
Abstract
Human gnathostomiasis is a parasitic disease caused by Gnathostoma nematode infection. A rapid, reliable, and practical immunoassay, named dot immuno-gold filtration assay (DIGFA), was developed to supporting clinical diagnosis of gnathostomiasis. The practical tool detected anti-Gnathostoma-specific IgG4 in human serum using crude extract of third-stage larvae as antigen. The result of the test was shown by anti-human IgG4 monoclonal antibody conjugated colloidal gold. The sensitivity and specificity of the test were both 100% for detection in human sera from patients with gnathostomiasis (13/13) and from healthy negative controls (50/50), respectively. Cross-reactivity with heterogonous serum samples from patients with other helminthiases ranged from 0 (trichinosis, paragonimiasis, clonorchiasis, schistosomiasis, and cysticercosis) to 25.0% (sparganosis), with an average of 6.3% (7/112). Moreover, specific IgG4 antibodies diminished at 6 months after treatment. This study showed that DIGFA for the detection of specific IgG4 in human sera could be a promising tool for the diagnosis of gnathostomiasis and useful for evaluating therapeutic effects.
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Affiliation(s)
- Yue Wang
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, P. R. China.,National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, P. R. China
| | - An Ma
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, P. R. China
| | - Xiao-Long Liu
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, P. R. China
| | - Praphathip Eamsobhana
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Xiao-Xian Gan
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, P. R. China
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Lessons learned for surveillance strategies for trachoma elimination as a public health problem, from the evaluation of approaches utilised by Guinea worm and onchocerciasis programmes: A literature review. PLoS Negl Trop Dis 2021; 15:e0009082. [PMID: 33507903 PMCID: PMC7872237 DOI: 10.1371/journal.pntd.0009082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/09/2021] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
Introduction A number of neglected tropical diseases are targeted for elimination or eradication. An effective surveillance system is critical to determine if these goals have been achieved and maintained. Trachoma has two related but morphologically different presentations that are monitored for elimination, the active infectious form of trachoma and trachomatous trichiasis (TT), the progression of the disease. There are a number of lessons learnt from the Guinea worm surveillance system that are particularly compatible for TT surveillance and the onchocerciasis surveillance system which can provide insights for surveillance of the infectious form of trachoma. Methods/Principal findings A literature search of peer-reviewed published papers and grey literature was conducted using PUBMED and Google Scholar for articles relating to dracunculiasis or Guinea worm, onchocerciasis and trachoma, along with surveillance or elimination or eradication. The abstracts of relevant papers were read and inclusion was determined based on specified inclusion and exclusion criteria. The credibility and bias of relevant papers were also critically assessed using published criteria. A total of 41 papers were identified that were eligible for inclusion into the review. The Guinea worm programme is designed around a surveillance-containment strategy and combines both active and passive surveillance approaches, with a focus on village-based surveillance and reporting. Although rumour reporting and a monetary incentive for the identification of confirmed Guinea worm cases have been reported as successful for identifying previously unknown transmission there is little unbiased evidence to support this conclusion. More rigorous evidence through a randomised controlled trial, influenced by motivational factors identified through formative research, would be necessary in order to consider applicability for TT case finding in an elimination setting. The onchocerciasis surveillance strategy focuses on active surveillance through sentinel surveillance of villages and breeding sites. It relies on an entomological component, monitoring infectivity rates of black flies and an epidemiological component, tracking exposure to infection in humans. Challenges have included the introduction of relatively complex diagnostics that are not readily available in onchocerciasis endemic countries and target thresholds, which are practically unattainable with current diagnostic tests. Although there is utility in monitoring for infection and serological markers in trachoma surveillance, it is important that adequate considerations are made to ensure evidence-based and achievable guidelines for their utility are put in place. Conclusions/Significance The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons for trachoma surveillance, pre- and post-validation. The use of a monetary reward for identification of TT cases and further exploration into the use of infection and serological indicators particularly in a post-validation setting to assist in identifying recrudescence would be of particular relevance. The next step would be a real-world evaluation of their relative applicability for trachoma surveillance. The design of a surveillance system needs to be carefully thought out to ensure it provides sufficient evidence to determine if a disease or infection is eliminated or eradicated. If inappropriate it can lead to on-going transmission and resurgence of infection or disease or the unnecessary continuation of interventions, wasting valuable resources. Guinea worm is a disease that is painful and debilitating, for which there is no drug or vaccine. The aim is to eradicate the disease and as such the Guinea worm programme is designed around a strategy of identification of cases and their containment to prevent onward transmission. Onchocerciasis if left untreated can lead to blindness. The aim is to eliminate the disease through the interruption of transmission. A literature review was conducted to determine available evidence and identify lessons that can be learnt from the surveillance of both diseases for the design of trachoma surveillance strategies in the endgame. The potential utility of rumour reporting and a monetary incentive for the identification of a confirmed case of Guinea worm could be explored for trichiasis case finding. Trichiasis is the progression of trachoma and leads to significant ocular morbidity. The introduction of tests for infection and antibodies and the utility of sentinel surveillance as utilised for onchocerciasis are interesting considerations for active trachoma surveillance post-validation and has potential to identify recrudescence cost-effectively. The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons that can be trialled for trachoma surveillance. However, their real-world applicability and implications for trachoma need to be evaluated before any changes in guidelines are proposed.
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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: 16] [Impact Index Per Article: 4.0] [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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Chu CS, Bancone G, Kelley M, Advani N, Domingo GJ, Cutiongo-de la Paz EM, van der Merwe N, Cohen J, Gerth-Guyette E. Optimizing G6PD testing for Plasmodium vivax case management and beyond: why sex, counseling, and community engagement matter. Wellcome Open Res 2020; 5:21. [PMID: 32766454 PMCID: PMC7388194 DOI: 10.12688/wellcomeopenres.15700.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2020] [Indexed: 01/02/2023] Open
Abstract
Safe access to the most effective treatment options for
Plasmodium vivax malaria are limited by the absence of accurate point-of-care testing to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common human genetic disorder. G6PD-deficient patients are at risk of life-threatening hemolysis when exposed to 8-aminoquinolines, the only class of drugs efficacious against
P. vivax hypnozoites. Until recently, only qualitative tests were available in most settings. These can identify patients with severe G6PD deficiency (mostly male) but not patients with intermediate G6PD deficiency (always female). This has led to and reinforced a gap in awareness in clinical practice of the risks and implications of G6PD deficiency in females—who, unlike males, can have a heterozygous genotype for G6PD. Increasing recognition of the need for radical cure of
P. vivax, first for patients’ health and then for malaria elimination, is driving the development of new point-of-care tests for G6PD deficiency and their accessibility to populations in low-resource settings. The availability of user-friendly, affordable, and accurate quantitative point-of-care diagnostics for the precise classification of the three G6PD phenotypes can reduce sex-linked disparities by ensuring safe and effective malaria treatment, providing opportunities to develop supportive counseling to enhance understanding of genetic test results, and improving the detection of all G6PD deficiency phenotypes in newborns and their family members.
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Affiliation(s)
- Cindy S Chu
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Germana Bancone
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Maureen Kelley
- The Ethox Centre and Wellcome Centre for Ethics and Humanities, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | | | | | - Eva M Cutiongo-de la Paz
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines.,Philippine Genome Center, University of the Philippines System, Quezon City, Philippines
| | - Nicole van der Merwe
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg Academic Hospital, Cape Town, South Africa
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Taylor EM. NTD Diagnostics for Disease Elimination: A Review. Diagnostics (Basel) 2020; 10:E375. [PMID: 32517108 PMCID: PMC7344624 DOI: 10.3390/diagnostics10060375] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/07/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022] Open
Abstract
Neglected Tropical Diseases (NTDs) marked out for disease elimination provide a lens through which to explore the changing status of diagnosis in global health. This paper reports on the findings of a scoping review, which set out to explore the main debates around diagnosis for the elimination of NTDs, including the multiple roles diagnostic technologies are being ascribed and the ideal characteristics of tests. It also attempts to summarise the state of diagnosis for three NTDs with elimination goals. The review places special emphasis on point-of-care testing in acknowledgement of the remote and underserved areas where NTDs proliferate. Early NTD campaigns were largely focused on attack phase planning, whereby a similar set of interventions could be transplanted anywhere. Now, with elimination goals in sight, strategies must be tailored to local settings if they are to attain and sustain success. Diagnostic data helps with local adaptation and is increasingly used for programmatic decision-making. The review finds that elimination goals reframe whom diagnosis is for and the myriad roles diagnostics can play. The exigencies of elimination also serve to highlight deficiencies in the current diagnostic arsenal and development pipeline for many NTDs. Moving forward, a guiding framework is needed to drive research and stimulate investment in diagnosis to support NTD goals.
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Affiliation(s)
- Emma Michelle Taylor
- Department of Social Anthropology, University of Edinburgh, Edinburgh EH8 9LD, UK
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Hotterbeekx A, Perneel J, Mandro M, Abhafule G, Siewe Fodjo JN, Dusabimana A, Abrams S, Kumar-Singh S, Colebunders R. Comparison of Diagnostic Tests for Onchocerca volvulus in the Democratic Republic of Congo. Pathogens 2020; 9:pathogens9060435. [PMID: 32498284 PMCID: PMC7350314 DOI: 10.3390/pathogens9060435] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/20/2020] [Accepted: 06/01/2020] [Indexed: 12/16/2022] Open
Abstract
Onchocerciasis is diagnosed by detecting microfilariae in skin snips or by detecting OV16 IgG4 antibodies in blood by either enzyme linked immunosorbent assay (ELISA) or a rapid diagnostic test (RDT). Here, we compare the sensitivity and specificity of these three tests in persons with epilepsy living in an onchocerciasis endemic region in the Democratic Republic of Congo. Skin snips and blood samples were collected from 285 individuals for onchocerciasis diagnosis. Three tests were performed: the OV16 RDT (SD Bioline) and the OV16 ELISA both on serum samples, and microscopic detection of microfilariae in skin snips. The sensitivity and specificity of each test was calculated with the combined other tests as a reference. Microfilariae were present in 105 (36.8%) individuals, with a median of 18.5 (6.5–72.0) microfilariae/skin snip. The OV16 RDT and OV16 ELISA were positive in, respectively, 112 (39.3%) and 143 (50.2%) individuals. The OV16 ELISA had the highest sensitivity among the three tests (83%), followed by the OV16 RDT (74.8%) and the skin snip (71.4%). The OV16 RDT had a higher specificity (98.6%) compared to the OV16 ELISA (84.8%). Our study confirms the need to develop more sensitive tests to ensure the accurate detection of ongoing transmission before stopping elimination efforts.
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Affiliation(s)
- An Hotterbeekx
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
- Correspondence: ; Tel.: +32-3-265-27-52; Fax: +32-3-265-26-63
| | - Jolien Perneel
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
| | - Michel Mandro
- Provincial Health Division Ituri, Ministry of Health, Bunia 185 DRC 57, Democratic Republic of Congo;
- Centre de Recherche en Maladies Tropicales, Rethy Box 143, Democratic Republic of Congo;
| | - Germain Abhafule
- Centre de Recherche en Maladies Tropicales, Rethy Box 143, Democratic Republic of Congo;
| | - Joseph Nelson Siewe Fodjo
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
| | - Alfred Dusabimana
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
| | - Steven Abrams
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
| | - Samir Kumar-Singh
- Molecular Pathology Group, Laboratory of Cell Biology & Histology, Faculty of Medicine and Health Sciences, University of Antwerp, 2000 Antwerp, Belgium;
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, 2000 Antwerp, Belgium; (J.P.); (J.N.S.F.); (A.D.); (S.A.); (R.C.)
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Mackenzie CD. A Much-Needed Advance in the Diagnosis of River Blindness. J Infect Dis 2020; 221:1746-1748. [DOI: 10.1093/infdis/jiz309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 11/14/2022] Open
Affiliation(s)
- Charles D Mackenzie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, Georgia
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Chu CS, Bancone G, Kelley M, Advani N, Domingo GJ, Cutiongo-de la Paz EM, van der Merwe N, Cohen J, Gerth-Guyette E. Optimizing G6PD testing for Plasmodium vivax case management: why sex, counseling, and community engagement matter. Wellcome Open Res 2020; 5:21. [DOI: 10.12688/wellcomeopenres.15700.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2020] [Indexed: 11/20/2022] Open
Abstract
Safe access to the most effective treatment options for Plasmodium vivax malaria are limited by the absence of accurate point-of-care testing to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common human genetic disorder. G6PD-deficient patients are at risk of life-threatening hemolysis when exposed to 8-aminoquinolines, the only class of drugs efficacious against P. vivax hypnozoites. Until recently, only qualitative tests were available in most settings. These accurately identify patients with severe G6PD deficiency (mostly male) but not patients with intermediate G6PD deficiency (always female). This has led to and reinforced a gap in awareness in clinical practice of the risks and implications of G6PD deficiency in females—who, unlike males, can have a heterozygous genotype for G6PD. Increasing recognition of the need for radical cure of P. vivax, first for patients’ health and then for malaria elimination, is driving the development of new point-of-care tests for G6PD deficiency and their accessibility to populations in low-resource settings. The availability of simple, affordable, and accurate point-of-care diagnostics for the precise classification of the three G6PD phenotypes can reduce sex-linked disparities by ensuring safe and effective malaria treatment, providing opportunities to develop supportive counseling to enhance understanding of genetic test results, and improving the detection of all G6PD deficiency phenotypes in newborns and their family members.
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Lagatie O, Verheyen A, Nijs E, Batsa Debrah L, Debrah YA, Stuyver LJ. Performance evaluation of 3 serodiagnostic peptide epitopes and the derived multi-epitope peptide OvNMP-48 for detection of Onchocerca volvulus infection. Parasitol Res 2019; 118:2263-2270. [PMID: 31089811 PMCID: PMC6611744 DOI: 10.1007/s00436-019-06345-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/30/2019] [Indexed: 02/04/2023]
Abstract
Current diagnostic tools to determine infection with the helminth parasite Onchocerca volvulus have limited performance characteristics. In previous studies, a proteome-wide screen was conducted to identify linear epitopes in this parasite’s proteome, resulting in the discovery of 1110 antigenic peptide fragments. Here, we investigated three of these peptides using peptide ELISA’s and evaluated their sensitivity and specificity. Epitope mapping was performed, and peptides were constructed that contained only the minimal epitope, flanked by a linker. Investigation of the performance of these minimal epitope peptides demonstrated that all three of them have a specificity (as defined by lack of response in non-helminth-infected individuals) of 100%, low cross-reactivity (5.6%, 5.6%, and 9.3%, respectively), but low sensitivity (36.9%, 46.5%, and 41.2%, respectively). Some cross-reactivity was observed in samples from individuals infected with soil-transmitted helminths or Brugia malayi. Combining these three minimal epitopes in a single peptide, called OvNMP-48, resulted in a performance that exceeded the sum of the individual epitopes, with a sensitivity of 76.0%, a specificity of 97.4%, and a cross-reactivity of 11.1%. Cross-reactivity was observed in some STH and Brugia malayi-infected individuals. This work opens the opportunity to start exploring how these novel linear epitope markers might become part of the O. volvulus diagnostic toolbox.
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Affiliation(s)
- Ole Lagatie
- Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340, Beerse, Belgium.
| | - Ann Verheyen
- Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Erik Nijs
- Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Linda Batsa Debrah
- Kumasi Centre for Collaborative Research into Tropical medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Yaw A Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Lieven J Stuyver
- Global Public Health, Janssen R&D, Turnhoutseweg 30, 2340, Beerse, Belgium
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20
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Siewe Fodjo JN, Tatah G, Tabah EN, Ngarka L, Nfor LN, Chokote SE, Mengnjo MK, Dema F, Sitouok AT, Nkoro G, Ntone FE, Bissek ACZK, Chesnais CB, Boussinesq M, Colebunders R, Njamnshi AK. Epidemiology of onchocerciasis-associated epilepsy in the Mbam and Sanaga river valleys of Cameroon: impact of more than 13 years of ivermectin. Infect Dis Poverty 2018; 7:114. [PMID: 30501640 DOI: 10.1186/s40249-018-0497-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/18/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A high epilepsy prevalence has been reported in several onchocerciasis-endemic villages along the Mbam and Sanaga river valleys in Cameroon, including Bilomo and Kelleng. We sought to determine the prevalence of epilepsy in these two villages following more than 13 years of community-directed treatment with ivermectin (CDTI). METHODS Door-to-door surveys were performed on the entire resident population in the villages in August 2017 and January 2018. Epilepsy was diagnosed using a 2-step approach: administration of a standardized 5-item questionnaire followed by confirmation by a neurologist. Previously published diagnostic criteria for onchocerciasis-associated epilepsy (OAE) were used. Ov16 serology was done for children aged 7-10 years to assess onchocerciasis transmission. Findings were compared with previous data from these two villages. RESULTS A total of 1525 individuals (1321 in Bilomo and 204 in Kelleng) in 233 households were surveyed in both villages. The crude prevalence of epilepsy was 4.6% in Bilomo (2017) and 7.8% in Kelleng (2018), including 12 (15.6% of cases) persons with epilepsy (PWE) with nodding seizures. The age and sex-standardized prevalence in Kelleng decreased from 13.5% in 2004 to 9.3% in 2018 (P < 0.001). The median age of PWE shifted from 17 (IQR: 12-22) years to 24 (IQR: 20-30) years in Bilomo (P < 0.001); and slightly from 24 (IQR: 14-34) years to 28 (IQR: 21.25-36.75) years in Kelleng (P = 0.112). Furthermore, 47.6% of all tested children between 7 and 10 years had Ov16 antibodies. CONCLUSIONS There is a decrease in epilepsy prevalence after 13 years and more of CDTI in both villages. The age-shift observed in PWE suggests that ivermectin may prevent OAE in younger residents. Ov16 seropositivity in children indicates ongoing onchocerciasis transmission possibly due to suboptimal control measures. Our findings support the existence of OAE in Cameroon and highlight the need to strengthen onchocerciasis elimination programs.
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Affiliation(s)
| | - Godwin Tatah
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neurology Department, CH Saint-Nazaire, Saint-Nazaire, France.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Earnest Njih Tabah
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Ministry of Public Health, Yaoundé, Cameroon
| | - Leonard Ngarka
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Leonard Njamnshi Nfor
- Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon.,Neurology Department, CHU Brugman, Brussels, Belgium
| | - Samuel Eric Chokote
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Michel K Mengnjo
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Fidèle Dema
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Yoko District Hospital, Yaoundé, Cameroon
| | - Aurélien Tele Sitouok
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Grace Nkoro
- Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Félicien E Ntone
- Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon
| | - Anne-Cécile Zoung-Kanyi Bissek
- Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon.,Ministry of Public Health, Yaoundé, Cameroon
| | - Cédric B Chesnais
- UMI 233, Institut de Recherche pour le Développement (IRD), Montpellier, France.,Université Montpellier, Montpellier, France.,INSERM Unité 1175, Montpellier, France
| | - Michel Boussinesq
- UMI 233, Institut de Recherche pour le Développement (IRD), Montpellier, France.,Université Montpellier, Montpellier, France.,INSERM Unité 1175, Montpellier, France
| | | | - Alfred K Njamnshi
- Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.,Neuroscience Laboratory, FMBS, The University of Yaoundé I, Yaoundé, Cameroon.,Brain Research Africa Initiative (BRAIN), Yaoundé, Cameroon
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21
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Bakajika D, Senyonjo L, Enyong P, Oye J, Biholong B, Elhassan E, Boakye D, Dixon R, Schmidt E. On-going transmission of human onchocerciasis in the Massangam health district in the West Region of Cameroon: Better understanding transmission dynamics to inform changes in programmatic interventions. PLoS Negl Trop Dis 2018; 12:e0006904. [PMID: 30427830 PMCID: PMC6261645 DOI: 10.1371/journal.pntd.0006904] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 11/28/2018] [Accepted: 10/06/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Massangam health district (HD), in the West Region of Cameroon, has received ivermectin mass drug administration (MDA) for 20 years, however there is evidence of continued high transmission of Onchocerca volvulus. In order to better understand the transmission dynamics in the HD and inform intervention strategies there is a need to delineate the boundaries of the suspected area of high transmission within the wider transmission zone. METHODOLOGY/PRINCIPAL FINDINGS Parasitological and entomological surveys were conducted to map out the breeding sites of Simulium damnosum and evaluate the prevalence of onchocerciasis in neighbouring communities, including Makouopsap sentinel community. Potential rapids were prospected for identification of S. damnosum larvae and black flies collected to determine infectivity rates. Adults were assessed for the presence of O. volvulus microfilariae through a skin snip biopsy and examined for the presence of nodules. Anti Ov-16 antibodies were tested for in children. Four perennial breeding sites were identified on the Rivers Mbam and Nja. Large number of flies were collected along the River Mbam, especially in the rainy season, with up to 955 flies per day, suggesting this river is a perennial source of black flies. A total of 0.8% of parous flies were infective across the study area. Parasitological studies provided evidence of high rates of infection in the sentinel community and three neighbouring communities, with 37.1% of adults microfilariae positive in Makouopsap. High Ov-16 seropositivity in children also provided evidence of recent on-going transmission. In comparison, communities sampled further away from the sentinel community and neighbouring breeding sites were much closer to reaching onchocerciasis elimination targets. CONCLUSIONS/SIGNIFICANCE This study provides evidence of a particular geographic area of high transmission in an approximate 12 km range around the sentinel community of Makouopsap and the neighbouring breeding sites on the River Nja. To eliminate onchocerciasis by 2025, there is a need to explore alternative intervention strategies in this area of high transmission.
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Affiliation(s)
| | | | | | | | | | | | - Daniel Boakye
- Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Ruth Dixon
- Sightsavers, Haywards Heath, United Kingdom
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Abstract
PURPOSE OF REVIEW With increasing international travel and mass global population migration, clinicians in nonendemic countries must be familiar with imported neglected tropical diseases including onchocerciasis, which is commonly known as 'river blindness'. RECENT FINDINGS Imported onchocerciasis manifests differently in travelers compared with migrants from endemic areas and is likely underdiagnosed in both groups. Recent clinical studies confirm that eosinophilia is not a sensitive marker for Onchocerca volvulus, with one-third of patients having a normal eosinophil count. Novel diagnostics measuring antibodies to multiple recombinant O. volvulus antigens maintain a high sensitivity while improving specificity compared with conventional pan-filarial serologic testing. A 6-week course of doxycycline has macrofilaricidal activity through Wolbachia depletion and may be useful in nonendemic areas in addition to standard serial ivermectin. SUMMARY Recent studies characterizing distinct clinical presentations in travelers and migrants may enable clinicians to better recognize imported onchocerciasis. Although novel diagnostics have improved specificity, most remain restricted to tropical disease reference laboratories and to date there is no marker of cure. Prolonged doxycycline treatment may reduce the need for serial ivermectin, though more potent short-course macrofilaricidal drugs are being developed.
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Affiliation(s)
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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23
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Murdoch ME. Onchodermatitis: Where Are We Now? Trop Med Infect Dis 2018; 3:E94. [PMID: 30274490 PMCID: PMC6160948 DOI: 10.3390/tropicalmed3030094] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 02/07/2023] Open
Abstract
Onchocerciasis causes debilitating pruritus and rashes as well as visual impairment and blindness. Prior to control measures, eye disease was particularly prominent in savanna areas of sub-Saharan Africa whilst skin disease was more common across rainforest regions of tropical Africa. Mass drug distribution with ivermectin is changing the global scene of onchocerciasis. There has been successful progressive elimination in Central and Southern American countries and the World Health Organization has set a target for elimination in Africa of 2025. This literature review was conducted to examine progress regarding onchocercal skin disease. PubMed searches were performed using keywords 'onchocerciasis', 'onchodermatitis' and 'onchocercal skin disease' over the past eight years. Articles in English, or with an English abstract, were assessed for relevance, including any pertinent references within the articles. Recent progress in awareness of, understanding and treatment of onchocercal skin disease is reviewed with particular emphasis on publications within the past five years. The global burden of onchodermatitis is progressively reducing and is no longer seen in children in many formerly endemic foci.
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Affiliation(s)
- Michele E Murdoch
- Department of Dermatology, West Herts Hospitals NHS Trust, Vicarage Road, Watford, Hertfordshire WD18 0HB, UK.
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24
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Herrador Z, Garcia B, Ncogo P, Perteguer MJ, Rubio JM, Rivas E, Cimas M, Ordoñez G, de Pablos S, Hernández-González A, Nguema R, Moya L, Romay-Barja M, Garate T, Barbre K, Benito A. Interruption of onchocerciasis transmission in Bioko Island: Accelerating the movement from control to elimination in Equatorial Guinea. PLoS Negl Trop Dis 2018; 12:e0006471. [PMID: 29723238 PMCID: PMC5953477 DOI: 10.1371/journal.pntd.0006471] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/15/2018] [Accepted: 04/22/2018] [Indexed: 11/18/2022] Open
Abstract
Background Onchocerciasis, also known as river blindness, is a parasitic disease. More than 99 percent of all cases occur in Africa. Bioko Island (Equatorial Guinea) is the only island endemic for onchocerciasis in the world. Since 2005, when vector Simulium yahense was eliminated, there have not been any reported cases of infection. This study aimed to demonstrate that updated WHO criteria for stopping mass drug administration (MDA) have been met. Methodology/Principal findings A cross-sectional study was conducted from September 2016 to January 2017. Participants were 5- to 9-year-old school children. Onchocerciasis/lymphatic Filariasis (LF, only in endemic districts) rapid diagnostic tests (RDTs) were performed. Blood spots were collected from RDT positive children and 10 percent of the RDT negatives to determine Ov16 and Wb123 IgG4 antibodies through enzyme-linked immunosorbent assay (ELISA). Skin snips were collected from RDT positives. Filarial detection was performed by PCR in positives and indeterminate sera. Black fly collection was carried out in traditional breeding sites. A total of 7,052 children, ranging from 5 to 9 years of age, were included in the study. Four children (0.06%) were Ov16 IgG4 RDT positives, but negative by ELISA Ov16, while 6 RDT negative children tested positive by ELISA. A total of 1,230 children from the Riaba and Baney districts were tested for LF. One child was Wb123 RDT positive (0.08%), but ELISA negative, while 3 RDT negative children were positive by Wb123 ELISA. All positive samples were negative by PCR for onchocerciasis and LF (in blood spot and skin snip). All fly collections and larval prospections in the traditional catching and prospection sites were negative. Conclusions/Significance WHO criteria have been met, therefore MDA in Bioko Island can be stopped. Three years of post-treatment surveillance should be implemented to identify any new occurrences of exposure or infection. Onchocerciasis, commonly called river blindness, is a chronic parasitic disease particularly prevalent in Africa. It is transmitted through the bites of infected Simulium blackflies. Onchocerciasis is endemic in Equatorial Guinea. Huge achievements have been made in human and vector control during the last two decades, especially on Bioko Island. Eliminating onchocerciasis transmission on Bioko is feasible given its isolation from other landmasses, which also reduces the risk of reinvasion by the disease vector. Recently updated WHO guidelines for stopping mass drug administration (MDA) and verifying elimination of human onchocerciasis (2016) established a new critical threshold to verify elimination of onchocerciasis transmission based on novel serological tests. We applied these techniques in a representative sample of 5- to 9-year-old school children. An entomological assessment was also carried out. We found no evidence of current infection or recent transmission. There was no evidence of onchocerciasis vectors, and our results from the sample population meet the current WHO serologic criteria for stopping MDA. Based on these results, we recommended to the Ministry of Health and Social Welfare of Equatorial Guinea that MDA on Bioko Island be stopped and that 3 years of post-treatment surveillance should be undertaken to identify any new occurrences of exposure or infection.
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Affiliation(s)
- Zaida Herrador
- National Centre for Tropical Medicine, Health Institute Carlos III (ISCIII in Spanish), Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- * E-mail:
| | - Belén Garcia
- National Centre for Tropical Medicine, Health Institute Carlos III (ISCIII in Spanish), Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Policarpo Ncogo
- National Centre for Tropical Medicine, Health Institute Carlos III (ISCIII in Spanish), Madrid, Spain
- Ministry of Health, Malabo, Equatorial Guinea
| | - Maria Jesus Perteguer
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- National Center of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Jose Miguel Rubio
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- National Center of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Eva Rivas
- Department of Preventive Medicine, University Hospital Nuestra Señora de la Candelaria, Tenerife, Spain
| | - Marta Cimas
- National School of Health, Institute of Health Carlos III, Madrid, Spain
| | - Guillermo Ordoñez
- Department of Preventive Medicine, University Hospital of Mostoles, Madrid, Spain
| | - Silvia de Pablos
- National Center of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Ana Hernández-González
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- National Center of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Rufino Nguema
- Ministry of Health, Malabo, Equatorial Guinea
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Laura Moya
- Jimenez Diaz Foundation University Hospital, Madrid, Spain
| | - María Romay-Barja
- National Centre for Tropical Medicine, Health Institute Carlos III (ISCIII in Spanish), Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Teresa Garate
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- National Center of Microbiology, Institute of Health Carlos III, Madrid, Spain
| | - Kira Barbre
- Neglected Tropical Disease Support Center, Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Agustín Benito
- National Centre for Tropical Medicine, Health Institute Carlos III (ISCIII in Spanish), Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
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Mahdy MAK, Abdul-Ghani R, Abdulrahman TAA, Al-Eryani SMA, Al-Mekhlafi AM, Alhaidari SAA, Azazy AA. Onchocerca volvulus infection in Tihama region - west of Yemen: Continuing transmission in ivermectin-targeted endemic foci and unveiled endemicity in districts with previously unknown status. PLoS Negl Trop Dis 2018; 12:e0006329. [PMID: 29505580 PMCID: PMC5854432 DOI: 10.1371/journal.pntd.0006329] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/15/2018] [Accepted: 02/20/2018] [Indexed: 11/29/2022] Open
Abstract
Background Onchocerciasis in Yemen is one of the most neglected diseases, where baseline estimates of onchocerciasis and monitoring of the impact of ivermectin regularly administered to the affected individuals on its transmission are lacking. Therefore, this study aimed to determine the anti-Ov16 IgG4 seroprevalence among local communities of Hodeidah and Al-Mahwit governorates of Tihama region. The factors possibly associated with previous exposure to infection were also studied. Methodology/Principal findings This cross-sectional study was conducted in two ivermectin-targeted districts endemic for onchocerciasis in Hodeidah and Al-Mahwit and two untargeted districts with unknown previous endemicity in Hodeidah between February and July 2017. For 508 residents sampled by a multi-stage random approach, data were collected and blood specimens were screened for anti-Ov16 IgG4 using the SD BIOLINE Onchocerciasis IgG4 rapid tests. The study revealed an overall anti-Ov16 IgG4 rate of 18.5% (94/508) in all surveyed districts, with 10.2% (12/118) of children aged ≤10 years being seropositive. Moreover, rates of 8.0% (4/50) and 6.1% (4/66) were found in districts not officially listed as endemic for the disease. Multivariable analysis confirmed the age of more than ten years and residing within a large family as the independent predictors of exposure to infection. Conclusions/Significance Onchocerciasis transmission is still ongoing as supported by the higher anti-Ov16 IgG4 seroprevalence rate among children aged ≤10 years compared to that (<0.1%) previously set by the World Health Organization as a serologic criterion for transmission interruption. Further large-scale studies combining serologic and entomologic criteria are recommended for the mapping of O. volvulus in human and blackfly populations in endemic foci and their neighboring areas of uncertain endemicity. In addition, ivermectin distribution, coverage and impact on disease transmission need to be continually assessed. Onchocerciasis is endemic in certain foci in the western governorates of Yemen. Monitoring the impact of the regular ivermectin administration to affected individuals on the transmission status and providing baseline onchocerciasis estimates in endemic areas are crucial for planning effective elimination strategies. We found that the disease transmission is still ongoing in Hodeidah and Al-Mahwit governorates of Tihama region as indicated by the anti-Ov16 IgG4 seropositivity among children aged ≤10 years. In Bani Sa'ad, where affected individuals had been regularly targeted with ivermectin over the last 15 years, we found that the anti-Ov16 IgG4 seroprevalence rate was significantly lower among children aged ≤10 years (9.1%; 5/55) compared to those >10 years (24.5%; 37/151), reflecting a possible decline in disease transmission. We also revealed onchocerciasis transmission in districts with unknown previous endemicity for the first time, with rates of 8.0% and 6.1% being found in Al Marawi'ah and As Sukhnah districts of Hodeidah. Large-scale surveys are recommended for mapping of O. volvulus in human and blackfly populations in endemic foci and neighboring untargeted areas of uncertain endemicity as a forward step towards the elimination of the disease from the country.
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Affiliation(s)
- Mohammed A. K. Mahdy
- Tropical Disease Research Center, University of Science and Technology, Sana’a, Yemen
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
- * E-mail:
| | - Rashad Abdul-Ghani
- Tropical Disease Research Center, University of Science and Technology, Sana’a, Yemen
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | | | - Samira M. A. Al-Eryani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Abdulsalam M. Al-Mekhlafi
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Sami A. A. Alhaidari
- National Schistosomiasis and Parasites Control Program, Ministry of Public Health and Population, Sana’a, Yemen
| | - Ahmed A. Azazy
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, KSA
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26
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Unnasch TR, Golden A, Cama V, Cantey PT. Diagnostics for onchocerciasis in the era of elimination. Int Health 2018; 10:i20-i26. [PMID: 29471336 PMCID: PMC5881263 DOI: 10.1093/inthealth/ihx047] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/19/2017] [Accepted: 11/06/2017] [Indexed: 12/31/2022] Open
Abstract
In the past few years, efforts to eliminate onchocerciasis from Africa have intensified. These efforts are primarily based on the mass distribution of the anti-helminthic drug Mectizan™ (ivermectin). This program has led to the development of new guidelines by the World Health Organization for the verification that transmission has been suppressed and eventually eliminated. The requirements of diagnostic tools for this purpose differ in many ways from tests used to diagnose infection in individuals. In this review, we summarize the progress that has been made to identify diagnostics that meet the specialized requirements needed to verify onchocerciasis elimination, discuss why these tests were selected and summarize the needs that still exist to complete the arsenal of diagnostic tools that will be useful as the goal of elimination is achieved.
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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
| | | | - Vitaliano Cama
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GAUSA
| | - Paul T Cantey
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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