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Amaral LJ, Jada SR, Ndjanfa AK, Carter JY, Abd-Elfarag G, Okaro S, Logora MY, Bol YY, Lakwo T, Fodjo JNS, Colebunders R. Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study. PLoS Negl Trop Dis 2024; 18:e0012059. [PMID: 38512994 PMCID: PMC10986994 DOI: 10.1371/journal.pntd.0012059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 04/02/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024] Open
Abstract
OBJECTIVES The potential impact of cumulative community-directed treatment with ivermectin (CDTI) on epilepsy epidemiology in Mvolo County, South Sudan, an onchocerciasis-endemic area with high epilepsy prevalence, was investigated. Annual CDTI was introduced in 2002 in Mvolo, with interruptions in 2016 and 2020. METHODS Comprehensive house-to-house surveys in Mvolo (June 2020 and 2022) identified cases of epilepsy, including probable nodding syndrome (pNS). Community workers screened households in selected sites for suspected epilepsy, and medical doctors confirmed the diagnosis and determined the year of seizure onset. The incidence of epilepsy, including pNS, was analysed using 95% confidence intervals (CIs). Data on ivermectin intake and onchocerciasis-associated manifestations (itching and blindness) were collected. RESULTS The surveys covered 15,755 (2020) and 15,092 (2022) individuals, identifying 809 (5.2%, 95% CI: 4.8-5.5%) and 672 (4.5%, 95% CI: 4.1-4.8%) epilepsy cases, respectively. Each survey reported that a third of the surveyed population experienced skin itching, and 3% were blind. Epilepsy incidence per 100,000 person-years gradually declined, from 326.5 (95% CI: 266.8-399.1) in 2013-2015 to 96.6 (95% CI: 65.5-141.7) in 2019-2021. Similarly, pNS incidence per 100,000 person-years decreased from 151.7 (95% CI: 112.7-203.4) to 27.0 (95% CI: 12.5-55.5). Coverage of CDTI was suboptimal, reaching only 64.0% of participants in 2019 and falling to 24.1% in 2021 following an interruption in 2020 due to COVID-19 restrictions. Additionally, while 99.4% of cases had active epilepsy in 2022, less than a quarter of these had access to antiseizure medication. CONCLUSIONS The observed decrease in epilepsy incidence despite suboptimal CDTI coverage highlights the potential impact of onchocerciasis control efforts and underscores the need to strengthen these efforts in Mvolo County and across South Sudan. As a proactive measure, Mvolo and neighbouring counties are transitioning to biannual CDTI. Furthermore, the substantial epilepsy treatment gap in Mvolo should be addressed.
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Affiliation(s)
| | | | | | | | - Gasim Abd-Elfarag
- Amref Health Africa, South Sudan
- Access for Humanity, Juba, South Sudan
- School of Public Health, University of Juba, Juba, South Sudan
| | | | - Makoy Yibi Logora
- Neglected Tropical Diseases Unit, Ministry of Health, Juba, South Sudan
| | - Yak Yak Bol
- Neglected Tropical Diseases Unit, Ministry of Health, Juba, South Sudan
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
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Mansour A, Rodriguez L, Mansour H, Yehia M, Battaglia Parodi M. Presumed Onchocerciasis Chorioretinitis Spilling over into North America, Europe and Middle East. Diagnostics (Basel) 2023; 13:3626. [PMID: 38132210 PMCID: PMC10743067 DOI: 10.3390/diagnostics13243626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 11/26/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Newer generation ophthalmologists practicing in the developed world are not very familiar with some tropical ocular diseases due to the absence of reports in the ophthalmic literature over the past thirty years. Because of world globalization or due to influx of immigrants from sub-Saharan Africa, exotic retinal diseases are being encountered more often in ophthalmology clinics. METHODS A multicenter case series of chorioretinitis or optic neuritis with obscure etiology that used serial multimodal imaging. RESULTS Four cases qualified with the diagnosis of presumed ocular onchocerciasis based on their residence near fast rivers in endemic areas, multimodal imaging, long term follow-up showing progressive disease and negative workup for other diseases. Characteristic findings include peripapillary choroiditis with optic neuritis or atrophy, subretinal tracts of the microfilaria, progressive RPE atrophy around heavily pigmented multifocal chorioretinal lesions of varying shapes, subretinal white or crystalline dots, and response to ivermectin. Typical skin findings are often absent in such patients with chorioretinitis rendering the diagnosis more challenging. CONCLUSIONS Familiarity with the myriad ocular findings of onchocerciasis, and a high-degree of suspicion in subjects residing in endemic areas can help in the correct diagnosis and implementation of appropriate therapy. Onchocercal chorioretinitis is a slow, insidious, progressive, and prolonged polymorphous disease.
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Affiliation(s)
- Ahmad Mansour
- Retina Service, Department of Ophthalmology, American University of Beirut, Beirut 1107, Lebanon
| | - Linnet Rodriguez
- Retina Service, Wills Eye Hospital, Thomas Jefferson Medical Center, Philadelphia, PA 19107, USA; (L.R.); (H.M.)
| | - Hana Mansour
- Retina Service, Wills Eye Hospital, Thomas Jefferson Medical Center, Philadelphia, PA 19107, USA; (L.R.); (H.M.)
| | - Madeleine Yehia
- Retina Service, University of Illinois Chicago, Chicago, IL 60612, USA;
| | - Maurizio Battaglia Parodi
- Retina Service, Department of Ophthalmology, Ospedale San Raffaele, University Vita-Salute, 20132 Milan, Italy;
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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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Kura K, Milton P, Hamley JID, Walker M, Bakajika DK, Kanza EM, Opoku NO, Howard H, Nigo MM, Asare S, Olipoh G, Attah SK, Mambandu GL, Kennedy KK, Kataliko K, Mumbere M, Halleux CM, Hopkins A, Kuesel AC, Kinrade S, Basáñez MG. Can mass drug administration of moxidectin accelerate onchocerciasis elimination in Africa? Philos Trans R Soc Lond B Biol Sci 2023; 378:20220277. [PMID: 37598705 PMCID: PMC10440165 DOI: 10.1098/rstb.2022.0277] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/11/2023] [Indexed: 08/22/2023] Open
Abstract
Epidemiological and modelling studies suggest that elimination of Onchocerca volvulus transmission (EoT) throughout Africa may not be achievable with annual mass drug administration (MDA) of ivermectin alone, particularly in areas of high endemicity and vector density. Single-dose Phase II and III clinical trials demonstrated moxidectin's superiority over ivermectin for prolonged clearance of O. volvulus microfilariae. We used the stochastic, individual-based EPIONCHO-IBM model to compare the probabilities of reaching EoT between ivermectin and moxidectin MDA for a range of endemicity levels (30 to 70% baseline microfilarial prevalence), treatment frequencies (annual and biannual) and therapeutic coverage/adherence values (65 and 80% of total population, with, respectively, 5 and 1% of systematic non-adherence). EPIONCHO-IBM's projections indicate that biannual (six-monthly) moxidectin MDA can reduce by half the number of years necessary to achieve EoT in mesoendemic areas and might be the only strategy that can achieve EoT in hyperendemic areas. Data needed to improve modelling projections include (i) the effect of repeated annual and biannual moxidectin treatment; (ii) inter- and intra-individual variation in response to successive treatments with moxidectin or ivermectin; (iii) the effect of moxidectin and ivermectin treatment on L3 development into adult worms; and (iv) patterns of adherence to moxidectin and ivermectin MDA. This article is part of the theme issue 'Challenges in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Philip Milton
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Jonathan I. D. Hamley
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
| | - Didier K. Bakajika
- Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), African Regional Office of the World Health Organization (WHO/AFRO/ESPEN), Brazzaville, Democratic Republic of Congo
| | - Eric M. Kanza
- Programme Nationale de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive (PNLMTN-CTP), Ministère de la Santé Publique, Kinshasa, Democratic Republic of the Congo
| | - Nicholas O. Opoku
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Hayford Howard
- Liberia Institute for Biomedical Research (LIBR), Monrovia, Liberia
| | - Maurice M. Nigo
- Institut Supérieur des Techniques Médicales de Nyankunde, Bunia, Democratic Republic of the Congo
| | | | - George Olipoh
- Precious Minerals Marketing Company, National Assay Centre, Technical Department, Diamond House, Accra, GA-143-2548, Ghana
| | - Simon K. Attah
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, Accra, Ghana
| | - Germain L. Mambandu
- Inspection Provinciale de la Santé de la Tshopo, Kisangani, Democratic Republic of the Congo
| | - Kambale Kasonia Kennedy
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Kambale Kataliko
- Centre de Santé CECA 20 de Mabakanga, Beni, Nord Kivu, Democratic Republic of the Congo
| | - Mupenzi Mumbere
- Medicines Development for Global Health, 18 Kavanagh Street, Southbank, Victoria 3006, Australia
| | - Christine M. Halleux
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
| | - Adrian Hopkins
- Neglected and Disabling Diseases of Poverty Consultant, Gravesend, Kent DA11 OSL, UK
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
| | - Sally Kinrade
- Medicines Development for Global Health, 18 Kavanagh Street, Southbank, Victoria 3006, Australia
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
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Hedtke SM, Kode A, Ukety TO, Mande JL, Abhafule GM, Raciu AA, Uvon CB, Jada SR, Hotterbeekx A, Siewe Fodjo JN, Mitreva M, Sebit W, Colebunders R, Grant WN, Kuesel AC. Procedure for Handling and Storage of Onchocerca volvulus Microfilariae Obtained from Skin Snips for Downstream Genetic Work. Trop Med Infect Dis 2023; 8:445. [PMID: 37755906 PMCID: PMC10536066 DOI: 10.3390/tropicalmed8090445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
WHO and endemic countries target elimination of transmission of Onchocerca volvulus, the parasite causing onchocerciasis. Population genetic analysis of O. volvulus may provide data to improve the evidence base for decisions on when, where, and for how long to deploy which interventions and post-intervention surveillance to achieve elimination. Development of necessary methods and tools requires parasites suitable for genetic analysis. Based on our experience with microfilariae obtained from different collaborators, we developed a microfilariae transfer procedure for large-scale studies in the Democratic Republic of Congo (DRC) comparing safety and efficacy of ivermectin, the mainstay of current onchocerciasis elimination strategies, and moxidectin, a new drug. This procedure is designed to increase the percentage of microfilariae in skin snips suitable for genetic analysis, improve assignment to metadata, and minimize time and materials needed by the researchers collecting the microfilariae. Among 664 microfilariae from South Sudan, 35.7% and 39.5% failed the mitochondrial and nuclear qPCR assay. Among the 576 microfilariae from DRC, 16.0% and 16.7% failed these assays, respectively. This difference may not only be related to the microfilariae transfer procedure but also to other factors, notably the ethanol concentration in the tubes in which microfilariae were stored (64% vs. ≥75%).
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Affiliation(s)
- Shannon M Hedtke
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia
| | - Anusha Kode
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia
| | - Tony O Ukety
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo
| | - Jöel L Mande
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo
| | - Germain M Abhafule
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo
| | - Anuarite A Raciu
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo
| | - Claude B Uvon
- Centre de Recherche en Maladies Tropicales (CRMT), Bunia P.O. Box 143, Democratic Republic of the Congo
| | | | - An Hotterbeekx
- Global Health Institute, University of Antwerp, 2610 Antwerp, Belgium
| | | | - Makedonka Mitreva
- Department of Medicine, Washington University in St. Louis and McDonnell Genome Institute, St. Louis, MO 63108, USA
| | - Wilson Sebit
- National Public Health Laboratory, Juba P.O. Box 88, South Sudan
| | | | - Warwick N Grant
- Department of Environment and Genetics, La Trobe University, Bundoora, VIC 3086, Australia
| | - Annette C Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, CH-1211 Geneva, Switzerland
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Otabil KB, Ankrah B, Bart-Plange EJ, Donkoh ES, Avarikame FA, Ofori-Appiah FO, Babae TN, Kudzordzi PC, Darko VA, Ameyaw J, Bamfo JG, Sakibu RA, Antwi-Berko D, Fodjo JNS, Basáñez MG, Schallig HDFH, Colebunders R. Prevalence of epilepsy in the onchocerciasis endemic middle belt of Ghana after 27 years of mass drug administration with ivermectin. Infect Dis Poverty 2023; 12:75. [PMID: 37587500 PMCID: PMC10433588 DOI: 10.1186/s40249-023-01117-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/29/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND In onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission, a high prevalence of epilepsy has been reported. This study aimed to determine the prevalence and clinical characteristics of epilepsy in the Bono Region of Ghana following 27 years of implementation of ivermectin mass drug administration (MDA). METHODS Between October 2020 and August 2021, cross-sectional surveys were conducted in nine communities in the Tain District and Wenchi Municipality of the Bono Region of Ghana. In the first stage, a random door-to-door approach was used to screen the population for epilepsy using a pre-tested questionnaire. Persons suspected of having epilepsy were invited for a second-stage neurological examination for case verification. Community O. volvulus microfilarial infection status and Ov16 seropositivity were also determined. Ninety-five confidence intervals (95% CI) for prevalence values were calculated using the Wilson Score Interval. RESULTS Of the 971 participants, 500 (51.5%) were females, and the median age (interquartile range) was 26 (15‒43) years. Fourteen participants (1.4%, 95% CI: 1.0‒2.0) were diagnosed as having epilepsy with generalized seizures being the most frequent seizure type (85.7%, 12/14). The overall microfilarial prevalence of O. volvulus was 10.3% (November 2020) and 9.9% (August 2021); the Ov16 seroprevalence was 22.2% (June 2021). Only 63.2% took ivermectin in the last round of MDA distribution in March 2021. CONCLUSIONS The 1.4% prevalence of epilepsy in the Bono region is similar to the median epilepsy prevalence in sub-Saharan Africa. However, the persistent microfilarial prevalence and low ivermectin study coverage call for the Ghana Onchocerciasis Elimination Programme to step up its efforts to ensure that the gains achieved are consolidated and improved to achieve the elimination of onchocerciasis by 2030.
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Affiliation(s)
- Kenneth Bentum Otabil
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana.
- Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana.
- Global Health Institute, University of Antwerp, Antwerp, Belgium.
| | - Blessing Ankrah
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Emmanuel John Bart-Plange
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Emmanuel Sam Donkoh
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Fiona Amoabil Avarikame
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Fredrick Obeng Ofori-Appiah
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Theophilus Nti Babae
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Prince-Charles Kudzordzi
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Vera Achiaa Darko
- NeTroDis Research Group, Centre for Research in Applied Biology, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
- STU Clinic, Sunyani Technical University, Bono Region, Sunyani, Ghana
| | - Joseph Ameyaw
- Happy Family Hospital, Bono East Region, Nkoranza, Ghana
| | | | - Raji Abdul Sakibu
- Department of Biological Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | - Daniel Antwi-Berko
- Department of Medical Laboratory Science, School of Sciences, University of Energy and Natural Resources, Bono Region, Sunyani, Ghana
| | | | - 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
| | - 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
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Forrest SL, Mercado CL, Engmann CM, Stacey AW, Hariharan L, Khan S, Cabrera MT. Does the Current Global Health Agenda Lack Vision? GLOBAL HEALTH, SCIENCE AND PRACTICE 2023; 11:GHSP-D-22-00091. [PMID: 36853641 PMCID: PMC9972379 DOI: 10.9745/ghsp-d-22-00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 12/06/2022] [Indexed: 01/11/2023]
Abstract
Given increasing rates of visual impairment worldwide, we call on national health plans and global development agencies to urgently focus funding and resources toward vision and eye health, with an emphasis on data collection surrounding new and changing burden of eye disease.
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Affiliation(s)
- Sam L. Forrest
- School of Medicine, University of Washington, Seattle, WA, USA
| | - Carmel L. Mercado
- Department of Ophthalmology, University of Washington, Seattle, WA, USA.,Division of Ophthalmology, Department of Surgery, Seattle Children’s Hospital, Seattle, WA, USA
| | - Cyril M. Engmann
- Department of Global Health, University of Washington, Seattle, WA, USA.,Division of Neonatology, Department of Pediatrics, University of Washington, Seattle, WA, USA.,PATH, Seattle, WA, USA
| | - Andrew W. Stacey
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Luxme Hariharan
- Division of Pediatric Ophthalmology, Chief of Pediatric Ophthalmology, Nicklaus Children’s Pediatric Specialists, Nicklaus Children’s Hospital, Miami, FL, USA
| | | | - Michelle T. Cabrera
- Department of Ophthalmology, University of Washington, Seattle, WA, USA.,Division of Ophthalmology, Department of Surgery, Seattle Children’s Hospital, Seattle, WA, USA.,Correspondence to Michelle Cabrera ()
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Shrestha H, McCulloch K, Hedtke SM, Grant WN. Geospatial modeling of pre-intervention nodule prevalence of Onchocerca volvulus in Ethiopia as an aid to onchocerciasis elimination. PLoS Negl Trop Dis 2022; 16:e0010620. [PMID: 35849615 PMCID: PMC9333447 DOI: 10.1371/journal.pntd.0010620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 07/28/2022] [Accepted: 06/28/2022] [Indexed: 11/19/2022] Open
Abstract
Background Onchocerciasis is a neglected tropical filarial disease transmitted by the bites of blackflies, causing blindness and severe skin lesions. The change in focus for onchocerciasis management from control to elimination requires thorough mapping of pre-control endemicity to identify areas requiring interventions and to monitor progress. Onchocerca volvulus nodule prevalence in sub-Saharan Africa is spatially continuous and heterogeneous, and highly endemic areas may contribute to transmission in areas of low endemicity or vice-versa. Ethiopia is one such onchocerciasis-endemic country with heterogeneous O. volvulus nodule prevalence, and many districts are still unmapped despite their potential for onchocerciasis transmission. Methodology/Principle findings A Bayesian geostatistical model was fitted for retrospective pre-intervention nodule prevalence data collected from 916 unique sites and 35,077 people across Ethiopia. We used multiple environmental, socio-demographic, and climate variables to estimate the pre-intervention prevalence of O. volvulus nodules across Ethiopia and to explore their relationship with prevalence. Prevalence was high in southern and northwestern Ethiopia and low in Ethiopia’s central and eastern parts. Distance to the nearest river (RR: 0.9850, 95% BCI: 0.9751–0.995), precipitation seasonality (RR: 0.9837, 95% BCI: 0.9681–0.9995), and flow accumulation (RR: 0.9586, 95% BCI: 0.9321–0.9816) were negatively associated with O. volvulus nodule prevalence, while soil moisture (RR: 1.0218, 95% BCI: 1.0135–1.0302) was positively associated. The model estimated the number of pre-intervention cases of O. volvulus nodules in Ethiopia to be around 6.48 million (95% BCI: 3.53–13.04 million). Conclusions/Significance Nodule prevalence distribution was correlated with habitat suitability for vector breeding and associated biting behavior. The modeled pre-intervention prevalence can be used as a guide for determining priorities for elimination mapping in regions of Ethiopia that are currently unmapped, most of which have comparatively low infection prevalence. Areas with unknown onchocerciasis endemicity may pose a threat to eliminating transmission because they may re-introduce onchocerciasis to areas where interventions have been successful. Additionally, because vectors (and thus Onchocerca volvulus transmission) have specific ecological requirements for growth and development, changes in these ecological factors due to human activities (deforestation, modification of river flows by dam construction, climate change) might change patterns of parasite transmission and endemicity. To estimate the impact of environmental changes, we must first identify ecological factors determining prevalence. We have employed Bayesian geostatistical modeling to create a nationwide O. volvulus nodule prevalence map for Ethiopia based on pre-intervention nodule prevalence data and have explored the effect of environmental variables on nodule prevalence. We estimated the number of pre-intervention cases of nodules and associated uncertainty in previously unmapped areas of Ethiopia to identify areas that need additional data to increase the prediction accuracy. Hydrological variables such as distance to the nearest river, precipitation seasonality, soil moisture, and flow accumulation are associated significantly with O. volvulus nodule prevalence. We show that the spatial distribution of nodule prevalence can be estimated based on ecological data and that predicted prevalence can be used as a guide to prioritize pre-intervention mapping.
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Affiliation(s)
- Himal Shrestha
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
| | - Karen McCulloch
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
- WHO Collaborating Centre for Viral Hepatitis, Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital, and Department of Infectious Diseases, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Shannon M. Hedtke
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
- * E-mail:
| | - Warwick N. Grant
- Department of Environment and Genetics, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
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9
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Anti-Th17 and anti-Th2 responses effects of hydro-ethanolic extracts of Aframomum melegueta, Khaya senegalensis and Xylopia aethiopica in hyperreactive onchocerciasis individuals’ peripheral blood mononuclear cells. PLoS Negl Trop Dis 2022; 16:e0010341. [PMID: 35468134 PMCID: PMC9071127 DOI: 10.1371/journal.pntd.0010341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 05/05/2022] [Accepted: 03/18/2022] [Indexed: 12/04/2022] Open
Abstract
Hyperreactive onchocerciasis (HO) is characterized by a severe skin inflammation with elevated Th17-Th2 combined responses. We previously demonstrated the anthelminthic activity of Aframomum melegueta (AM), Xylopia aethiopica (XA) and Khaya senegalensis (KS) used by traditional healers to treat helminthiasis in the endemic area of Togo. However, their effect on severe onchocerciasis is poorly investigated. The present study aimed to investigate the anti-Th17 and anti-Th2 effects of hydro-ethanolic extracts of AM, XA and KS during HO. Onchocerca volvulus-infected individuals were recruited in the Central region of Togo in 2018. Isolated peripheral blood mononuclear cells (PBMCs) from both generalized onchocerciasis (GEO) and HO forms were activated with anti-CD3 and anti-CD28 monoclonal antibodies in the presence or absence of the hydro-ethanolic extracts of AM, XA and KS as well as their delipidated, deproteinized and deglycosylated fractions. After 72 hours, cytokines were assayed from cell culture supernatants. Then, flow cytometry was used to investigate the effects of the extracts on cell activation, proliferation, intracellular cytokines and T cells transcription factors. The production of both Th17 and Th2 cytokines IL-17A and IL-5 were significantly inhibited upon T-cell receptor (TCR) activation in the presence of the hydro-ethanolic extracts of AM, XA and KS in HO individuals’ PBMCs in vitro. AM and XA inhibited CD4+RORC2+IL-17A+ and CD4+GATA3+IL-4+ cell populations induction. This inhibition was not Th1 nor Treg-dependent since both IFN-γ and IL-10 were also inhibited by the extracts. AM and XA did not interfere with T cell activation and proliferation for their inhibitory pathways. Lipid and protein compounds from AM and XA were associated with the inhibition of IL-17A. This study showed that in addition to their anthelminthic effects, hydro-ethanolic extracts of Aframomum melegueta, Xylopia aethiopica and Khaya senegalensis could downregulate both Th17 and Th2 responses and prevent the severe skin disorder observed. Severe form of human onchocerciasis also called hyperreactive onchocerciasis (HO) is characterized by skin disorders such as dermatitis. Our previous study showed that concomitant Th2 and Th17 responses play a role in the pathophysiology of the disease. In Onchocerca volvulus endemic areas such as Togo, traditional healers (TH) used to treat this disease with medicinal plants such as Aframomum melegueta (AM), Xylopia aethiopica (XA) and Khaya senegalensis (KS). Mass drug administration including ivermectin and albendazole has been used over the past decade to control and eradicate helminths infections. Despite its successes, resistance to ivermectin has been reported and therefore, alternative drugs are urgently needed. We previously confirmed in vitro the anthelminthic effects of Aframomum melegueta (AM), Xylopia aethiopica (XA) and Khaya senegalensis (KS). However, their effect on severe onchocerciasis has not been demonstrated. Here, the anti-Th17 and anti-Th2 effects of hydro-ethanolic extracts of AM, XA and KS during HO were investigated. The data showed that in addition to their helminth-killing effects, plant-derived molecules AM, XA and KS downregulated Th2 and Th17 profiles and therefore, could be candidates for the development of new drugs not only for the treatment of helminth-induced inflammatory pathologies but also auto-immune Th2/Th17-dependent inflammatory diseases in general.
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10
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Ashford J, Reis-Cunha J, Lobo I, Lobo F, Campelo F. Organism-specific training improves performance of linear B-cell epitope prediction. Bioinformatics 2021; 37:4826-4834. [PMID: 34289025 PMCID: PMC8665745 DOI: 10.1093/bioinformatics/btab536] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/01/2021] [Accepted: 07/19/2021] [Indexed: 12/25/2022] Open
Abstract
MOTIVATION In silico identification of linear B-cell epitopes represents an important step in the development of diagnostic tests and vaccine candidates, by providing potential high-probability targets for experimental investigation. Current predictive tools were developed under a generalist approach, training models with heterogeneous datasets to develop predictors that can be deployed for a wide variety of pathogens. However, continuous advances in processing power and the increasing amount of epitope data for a broad range of pathogens indicate that training organism or taxon-specific models may become a feasible alternative, with unexplored potential gains in predictive performance. RESULTS This article shows how organism-specific training of epitope prediction models can yield substantial performance gains across several quality metrics when compared to models trained with heterogeneous and hybrid data, and with a variety of widely used predictors from the literature. These results suggest a promising alternative for the development of custom-tailored predictive models with high predictive power, which can be easily implemented and deployed for the investigation of specific pathogens. AVAILABILITY AND IMPLEMENTATION The data underlying this article, as well as the full reproducibility scripts, are available at https://github.com/fcampelo/OrgSpec-paper. The R package that implements the organism-specific pipeline functions is available at https://github.com/fcampelo/epitopes. SUPPLEMENTARY INFORMATION Supplementary materials are available at Bioinformatics online.
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Affiliation(s)
- Jodie Ashford
- Department of Computer Science, College of Engineering and Physical Sciences, Aston University, Birmingham B4 7ET, UK
| | - João Reis-Cunha
- Department of Preventive Veterinary Medicine, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Igor Lobo
- Graduate Program in Genetics, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Francisco Lobo
- Department of General Biology, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Felipe Campelo
- Department of Computer Science, College of Engineering and Physical Sciences, Aston University, Birmingham B4 7ET, UK
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11
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Kwofie SK, Broni E, Yunus FU, Nsoh J, Adoboe D, Miller WA, Wilson MD. Molecular Docking Simulation Studies Identifies Potential Natural Product Derived-Antiwolbachial Compounds as Filaricides against Onchocerciasis. Biomedicines 2021; 9:biomedicines9111682. [PMID: 34829911 PMCID: PMC8615632 DOI: 10.3390/biomedicines9111682] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Onchocerciasis is the leading cause of blindness and severe skin lesions which remain a major public health problem, especially in tropical areas. The widespread use of antibiotics and the long duration required for effective treatment continues to add to the increasing global menace of multi-resistant pathogens. Onchocerca volvulus harbors the endosymbiont bacteria Wolbachia, essential for the normal development of embryos, larvae and long-term survival of the adult worm, O. volvulus. We report here results of using structure-based drug design (SBDD) approach aimed at identifying potential novel Wolbachia inhibitors from natural products against the Wolbachia surface protein (WSP). The protein sequence of the WSP with UniProtKB identifier Q0RAI4 was used to model the three-dimensional (3D) structure via homology modelling techniques using three different structure-building algorithms implemented in Modeller, I-TASSER and Robetta. Out of the 15 generated models of WSP, one was selected as the most reasonable quality model which had 82, 15.5, 1.9 and 0.5% of the amino acid residues in the most favored regions, additionally allowed regions, generously allowed regions and disallowed regions, respectively, based on the Ramachandran plot. High throughput virtual screening was performed via Autodock Vina with a library comprising 42,883 natural products from African and Chinese databases, including 23 identified anti-Onchocerca inhibitors. The top six compounds comprising ZINC000095913861, ZINC000095486235, ZINC000035941652, NANPDB4566, acetylaleuritolic acid and rhemannic acid had binding energies of −12.7, −11.1, −11.0, −11, −10.3 and −9.5 kcal/mol, respectively. Molecular dynamics simulations including molecular mechanics Poisson-Boltzmann (MMPBSA) calculations reinforced the stability of the ligand-WSP complexes and plausible binding mechanisms. The residues Arg45, Tyr135, Tyr148 and Phe195 were predicted as potential novel critical residues required for ligand binding in pocket 1. Acetylaleuritolic acid and rhemannic acid (lantedene A) have previously been shown to possess anti-onchocercal activity. This warrants the need to evaluate the anti-WSP activity of the identified molecules. The study suggests the exploitation of compounds which target both pockets 1 and 2, by investigating their potential for effective depletion of Wolbachia. These compounds were predicted to possess reasonably good pharmacological profiles with insignificant toxicity and as drug-like. The compounds were computed to possess biological activity including antibacterial, antiparasitic, anthelmintic and anti-rickettsials. The six natural products are potential novel antiwolbachial agents with insignificant toxicities which can be explored further as filaricides for onchocerciasis.
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Affiliation(s)
- Samuel K. Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra LG 77, Ghana; (E.B.); (F.U.Y.); (J.N.); (D.A.)
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra LG 54, Ghana
- Correspondence: ; Tel.: +233-203-797922
| | - Emmanuel Broni
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra LG 77, Ghana; (E.B.); (F.U.Y.); (J.N.); (D.A.)
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra LG 54, Ghana
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, P.O. Box LG 581, Legon, Accra LG 581, Ghana;
| | - Faruk U. Yunus
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra LG 77, Ghana; (E.B.); (F.U.Y.); (J.N.); (D.A.)
| | - John Nsoh
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra LG 77, Ghana; (E.B.); (F.U.Y.); (J.N.); (D.A.)
| | - Dela Adoboe
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic and Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra LG 77, Ghana; (E.B.); (F.U.Y.); (J.N.); (D.A.)
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Maywood, IL 60153, USA;
- Department of Molecular Pharmacology and Neuroscience, Loyola University Medical Center, Maywood, IL 60153, USA
- Department of Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, IL 19104, USA
| | - Michael D. Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, P.O. Box LG 581, Legon, Accra LG 581, Ghana;
- Department of Medicine, Loyola University Medical Center, Maywood, IL 60153, USA;
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12
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Hübner MP, Townson S, Gokool S, Tagboto S, Maclean MJ, Verocai GG, Wolstenholme AJ, Frohberger SJ, Hoerauf A, Specht S, Scandale I, Harder A, Glenschek-Sieberth M, Hahnel SR, Kulke D. Evaluation of the in vitro susceptibility of various filarial nematodes to emodepside. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2021; 17:27-35. [PMID: 34339934 PMCID: PMC8347670 DOI: 10.1016/j.ijpddr.2021.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/19/2021] [Accepted: 07/24/2021] [Indexed: 11/25/2022]
Abstract
Filariae are vector-borne nematodes responsible for an enormous burden of disease. Human lymphatic filariasis, caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori, and onchocerciasis (caused by Onchocerca volvulus) are neglected parasitic diseases of major public health significance in tropical regions. To date, therapeutic efforts to eliminate human filariasis have been hampered by the lack of a drug with sufficient macrofilaricidal and/or long-term sterilizing effects that is suitable for use in mass drug administration (MDA) programs, particularly in areas co-endemic with Loa loa, the causative agent of loiasis. Emodepside, a semi-synthetic cyclooctadepsipeptide, has been shown to have broad-spectrum efficacy against gastrointestinal nematodes in a variety of mammalian hosts, and has been approved as an active ingredient in dewormers for cats and dogs. This paper evaluates, compares (where appropriate) and summarizes the in vitro effects of emodepside against a range of filarial nematodes at various developmental stages. Emodepside inhibited the motility of all tested stages of filariae frequently used as surrogate species for preclinical investigations (Acanthocheilonema viteae, Brugia pahangi, Litomosoides sigmodontis, Onchocerca gutturosa, and Onchocerca lienalis), human-pathogenic filariae (B. malayi) and filariae of veterinary importance (Dirofilaria immitis) in a concentration-dependent manner. While motility of all filariae was inhibited, both stage- and species-specific differences were observed. However, whether these differences were detected because of stage- and/or species-specific factors or as a consequence of variations in protocol parameters among the participating laboratories (such as purification of the parasites, read-out units, composition of media, incubation conditions, duration of incubation etc.) remains unclear. This study, however, clearly shows that emodepside demonstrates broad-spectrum in vitro activity against filarial nematode species across different genera and can therefore be validated as a promising candidate for the treatment of human filariases, including onchocerciasis and lymphatic filariasis.
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Affiliation(s)
- Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.
| | - Simon Townson
- Griffin Institute (formerly Northwick Park Institute for Medical Research), London, HA1 3UJ, United Kingdom.
| | - Suzanne Gokool
- Griffin Institute (formerly Northwick Park Institute for Medical Research), London, HA1 3UJ, United Kingdom.
| | - Senyo Tagboto
- Griffin Institute (formerly Northwick Park Institute for Medical Research), London, HA1 3UJ, United Kingdom.
| | - Mary J Maclean
- National Institutes of Health, National Eye Institute, Clinical and Translational Immunology Section, Laboratory of Immunology, 10 Center Drive, Building 10, Room 10N113, Bethesda, MD, 20892, USA.
| | - Guilherme G Verocai
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, (current Address: INRAE Centre Val de Loire, 37380 Nouzilly, France), Athens, GA, 30602, USA; Department of Veterinary Pathobiology, College of Veterinary & Biomedical Sciences, Texas A&M University, 4467 TAMU College Station, TX, 77843, USA.
| | - Adrian J Wolstenholme
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Drive, (current Address: INRAE Centre Val de Loire, 37380 Nouzilly, France), Athens, GA, 30602, USA.
| | - Stefan J Frohberger
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.
| | - Sabine Specht
- Drugs for Neglected Diseases Initiative, Geneva, Switzerland.
| | - Ivan Scandale
- Drugs for Neglected Diseases Initiative, Geneva, Switzerland.
| | - Achim Harder
- Independent Scholar, Europaring 54, 51109, Cologne, Germany.
| | | | - Steffen R Hahnel
- Elanco Animal Health, Alfred-Nobel-Str. 50, 40789, Monheim, Germany.
| | - Daniel Kulke
- Elanco Animal Health, Alfred-Nobel-Str. 50, 40789, Monheim, Germany; Iowa State University, Department of Biomedical Sciences, 2008 Vet Med, Ames, IA, 50011, United States.
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13
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Krücken J, Holden-Dye L, Keiser J, Prichard RK, Townson S, Makepeace BL, Hübner MP, Hahnel SR, Scandale I, Harder A, Kulke D. Development of emodepside as a possible adulticidal treatment for human onchocerciasis-The fruit of a successful industrial-academic collaboration. PLoS Pathog 2021; 17:e1009682. [PMID: 34293063 PMCID: PMC8297762 DOI: 10.1371/journal.ppat.1009682] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Current mass drug administration (MDA) programs for the treatment of human river blindness (onchocerciasis) caused by the filarial worm Onchocerca volvulus rely on ivermectin, an anthelmintic originally developed for animal health. These treatments are primarily directed against migrating microfilariae and also suppress fecundity for several months, but fail to eliminate adult O. volvulus. Therefore, elimination programs need time frames of decades, well exceeding the life span of adult worms. The situation is worsened by decreased ivermectin efficacy after long-term therapy. To improve treatment options against onchocerciasis, a drug development candidate should ideally kill or irreversibly sterilize adult worms. Emodepside is a broad-spectrum anthelmintic used for the treatment of parasitic nematodes in cats and dogs (Profender and Procox). Our current knowledge of the pharmacology of emodepside is the result of more than 2 decades of intensive collaborative research between academia and the pharmaceutical industry. Emodepside has a novel mode of action with a broad spectrum of activity, including against extraintestinal nematode stages such as migrating larvae or macrofilariae. Therefore, emodepside is considered to be among the most promising candidates for evaluation as an adulticide treatment against onchocerciasis. Consequently, in 2014, Bayer and the Drugs for Neglected Diseases initiative (DNDi) started a collaboration to develop emodepside for the treatment of patients suffering from the disease. Macrofilaricidal activity has been demonstrated in various models, including Onchocerca ochengi in cattle, the parasite most closely related to O. volvulus. Emodepside has now successfully passed Phase I clinical trials, and a Phase II study is planned. This Bayer–DNDi partnership is an outstanding example of “One World Health,” in which experience gained in veterinary science and drug development is translated to human health and leads to improved tools to combat neglected tropical diseases (NTDs) and shorten development pathways and timelines in an otherwise neglected area. Onchocerca volvulus is the causative agent of human river blindness, and current elimination programs rely on the use of ivermectin to kill microfilariae. Since no adulticidal drug is available and adult worms have a life span of up to 15 years, elimination programs need to be sustained over several decades. Emodepside is an anthelmintic that is licensed as a dewormer for cats and dogs. Due to its ability to eliminate nematodes located in various extraintestinal host tissues, including migrating larvae and adult filarial worms, it is considered to be an excellent candidate for the treatment of onchocerciasis. Intense collaboration between academia and the pharmaceutical industry has led to a deep understanding of the novel mode of action of the drug and of its parasite target spectrum. Phase I clinical trials with emodepside have demonstrated its safety and adulticide activity against the closely related cattle parasite Onchocerca ochengi. Currently, Phase II clinical trials are planned to confirm that emodepside, developed initially to improve animal health, has also the potential to improve human health by tackling a very important neglected tropical disease (NTD).
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Affiliation(s)
- Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Lindy Holden-Dye
- School of Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Roger K. Prichard
- Institute of Parasitology, McGill University, Sainte Anne-de-Bellevue, Quebec, Canada
| | - Simon Townson
- The Griffin Institute, Northwick Park and St. Mark’s Hospital, Harrow, United Kingdom
| | - Benjamin L. Makepeace
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Marc P. Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Steffen R. Hahnel
- Elanco Animal Health, Research & Exploratory Development, Monheim, Germany
| | - Ivan Scandale
- Drugs for Neglected Disease initiative, Geneva, Switzerland
| | | | - Daniel Kulke
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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14
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Batsa Debrah L, Klarmann-Schulz U, Osei-Mensah J, Dubben B, Fischer K, Mubarik Y, Ayisi-Boateng NK, Ricchiuto A, Fimmers R, Konadu P, Nadal J, Gruetzmacher B, Weil G, Kazura JW, King CL, Debrah AY, Hoerauf A. Comparison of Repeated Doses of Ivermectin Versus Ivermectin Plus Albendazole for the Treatment of Onchocerciasis: A Randomized, Open-label, Clinical Trial. Clin Infect Dis 2021; 71:933-943. [PMID: 31536624 PMCID: PMC7428389 DOI: 10.1093/cid/ciz889] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 09/13/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Improved treatment for onchocerciasis is needed to accelerate onchocerciasis elimination in Africa. Aiming to better exploit registered drugs, this study was undertaken to determine whether annual or semiannual treatment with ivermectin (IVM; 200 µg/kg) plus albendazole (ALB; 800 mg single dose) is superior to IVM alone. METHODS This trial was performed in Ghana and included 272 participants with microfilariae (MF), who were randomly assigned to 4 treatment arms: (1) IVM annually at 0, 12, and 24 months; (2) IVM semiannually at 0, 6, 12, 18, and 24 months; (3) IVM+ALB annually; or (4) IVM+ALB semiannually. Microfiladermia was determined pretreatment and at 6, 18, and 36 months. The primary outcome was the proportion of fertile and viable female worms in onchocercomata excised at 36 months. RESULTS Posttreatment nodule histology showed that 15/135 (11.1%), 22/155 (14.2%), 35/154 (22.7%), and 20/125 (16.0%) living female worms had normal embryogenesis in the IVM annual, IVM semiannual, IVM+ALB annual, and IVM+ALB semiannual groups, respectively (P = .1229). Proportions of dead worms also did not differ between the 4 groups (P = .9198). Proportions of patients without MF at 36 months (1 year after the last treatment) were 35/56 (63%) after annual IVM, 42/59 (71%) after semiannual IVM, 39/64 (61%) after annual IVM+ALB, and 43/53 (81%) after semiannual IVM+ALB. CONCLUSIONS The combination treatment of IVM plus ALB was no better than IVM alone for sterilizing, killing adult worms, or achieving sustained MF clearance. However, semiannual treatment was superior to annual treatment for achieving sustained clearance of Onchocerca volvulus MF from the skin (P = .024). CLINICAL TRIALS REGISTRATION ISRCTN50035143.
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Affiliation(s)
- Linda Batsa Debrah
- Kumasi Center for Collaborative Research, Kumasi, Ghana.,Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ute Klarmann-Schulz
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany.,German Center for Infection Research, Bonn-Cologne site, Germany.,Institute for Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Germany
| | | | - Bettina Dubben
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Kerstin Fischer
- Infectious Diseases Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Yusif Mubarik
- Kumasi Center for Collaborative Research, Kumasi, Ghana
| | | | - Arcangelo Ricchiuto
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Rolf Fimmers
- Institute for Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Germany
| | - Peter Konadu
- School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Jennifer Nadal
- Institute for Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Germany
| | - Barbara Gruetzmacher
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Gary Weil
- Infectious Diseases Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - James W Kazura
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Veterans Affairs Medical Center, Cleveland, Ohio
| | - Alexander Y Debrah
- Kumasi Center for Collaborative Research, Kumasi, Ghana.,Faculty for Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany.,German Center for Infection Research, Bonn-Cologne site, Germany
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15
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Cheke RA, Little KE, Young S, Walker M, Basáñez MG. Taking the strain out of onchocerciasis? A reanalysis of blindness and transmission data does not support the existence of a savannah blinding strain of onchocerciasis in West Africa. ADVANCES IN PARASITOLOGY 2021; 112:1-50. [PMID: 34024357 DOI: 10.1016/bs.apar.2021.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Onchocerciasis (also known as 'river blindness'), is a neglected tropical disease (NTD) caused by the (Simulium-transmitted) filarial nematode Onchocerca volvulus. The occurrence of 'blinding' (savannah) and non-blinding (forest) parasite strains and the existence of corresponding, locally adapted Onchocerca-Simulium complexes were postulated to explain greater blindness prevalence in savannah than in forest foci. As a result, the World Health Organization (WHO) Onchocerciasis Control Programme in West Africa (OCP) focused anti-vectorial and anti-parasitic interventions in savannah endemic areas. In this paper, village-level data on blindness prevalence, microfilarial prevalence, and transmission intensity (measured by the annual transmission potential, the number of infective, L3, larvae per person per year) were extracted from 16 West-Central Africa-based publications, and analysed according to habitat (forest, forest-savannah mosaic, savannah) to test the dichotomous strain hypothesis in relation to blindness. When adjusting for sample size, there were no statistically significant differences in blindness prevalence between the habitats (one-way ANOVA, P=0.68, mean prevalence for forest=1.76±0.37 (SE); mosaic=1.49±0.38; savannah=1.89±0.26). The well-known relationship between blindness prevalence and annual transmission potential for savannah habitats was confirmed and shown to hold for (but not to be statistically different from) forest foci (excluding data from southern Côte d'Ivoire, in which blindness prevalence was significantly lower than in other West African forest communities, but which had been the focus of studies leading to the strain-blindness hypothesis that was accepted by OCP planners). We conclude that the evidence for a savannah blinding onchocerciasis strain in simple contrast with a non-blinding forest strain is equivocal. A re-appraisal of the strain hypothesis to explain patterns of ocular disease is needed to improve understanding of onchocerciasis epidemiology and disease burden estimates in the light of the WHO 2030 goals for onchocerciasis.
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Affiliation(s)
- Robert A Cheke
- Natural Resources Institute, Department of Agriculture, Health & Environment, University of Greenwich at Medway, Kent, United Kingdom; London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom
| | | | - Stephen Young
- Natural Resources Institute, Department of Agriculture, Health & Environment, University of Greenwich at Medway, Kent, United Kingdom
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Pathobiology and Populations Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom; MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom.
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16
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Progress towards onchocerciasis elimination in Côte d'Ivoire: A geospatial modelling study. PLoS Negl Trop Dis 2021; 15:e0009091. [PMID: 33566805 PMCID: PMC7875389 DOI: 10.1371/journal.pntd.0009091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/01/2021] [Indexed: 11/19/2022] Open
Abstract
Background Côte d’Ivoire has had 45 years of intervention for onchocerciasis by vector control (from 1975 to 1991), ivermectin mass drug administration (MDA) (from 1992 to 1994) and community directed treatment with ivermectin (CDTi) from 1995 to the present. We modeled onchocerciasis endemicity during two time periods that correspond to the scale up of vector control and ivermectin distribution, respectively. This analysis illustrates progress towards elimination during these periods, and it has identified potential hotspots areas that are at risk for ongoing transmission. Methods and findings The analysis used Ministry of Health skin snip microfilaria (MF) prevalence and intensity data collected between 1975 and 2016. Socio-demographic and environmental factors were incorporated into a predictive, machine learning algorithm to create continuous maps of onchocerciasis endemicity. Overall predicted mean MF prevalence decreased from 51.8% circa 1991 to 3.9% circa 2016. The model predicted infection foci with higher prevalence in the southern region of the country. Predicted mean community MF load (CMFL) decreased from 10.1MF/snip circa 1991 to 0.1MF/snip circa 2016. Again, the model predicts foci with higher Mf densities in the southern region. For assessing model performance, the root mean squared error and R2 values were 1.14 and 0.62 respectively for a model trained with data collected prior to 1991, and 1.28 and 0.57 for the model trained with infection survey data collected later, after the introduction of ivermectin. Finally, our models show that proximity to permanent inland bodies of water and altitude were the most informative variables that correlated with onchocerciasis endemicity. Conclusion/Significance This study further documents the significant reduction of onchocerciasis infection following widespread use of ivermectin for onchocerciasis control in Côte d’Ivoire. Maps produced predict areas at risk for ongoing infection and transmission. Onchocerciasis might be eliminated in Côte d’Ivoire in the future with a combination of sustained CDTi with high coverage, active surveillance, and close monitoring for persistent infection in previously hyper-endemic areas. Côte d’Ivoire is endemic for onchocerciasis (also known as “river blindness”). This neglected tropical disease is transmitted by biting black flies that breed in fast flowing rivers. From 1975 to 1991, onchocerciasis control was based on weekly aerial spraying of the insecticide temephos, on black fly breeding sites. Vector control, however, was mostly focused on the northern and central parts of the country. From 1992 to present, mass treatment with ivermectin was implemented in all endemic areas, including forested regions in the south. Here we present the first geospatial estimates of onchocerciasis endemicity over time. Using the machine learning algorithm quantile regression forest, we implemented models to: identify important socio-demographic and environmental factors that correlate with onchocerciasis infection; predict the prevalence and density of infection in areas without ground-truth data; delineate remaining infection hotspots. Our results show that Côte d’Ivoire has made very significant progress in reducing infection parameters over time, and they may help to inform future interventions to achieve the goal of onchocerciasis elimination in Côte d’Ivoire.
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17
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Ganong CN. A Multimedia Active Learning Approach to Introducing Human Parasitic Diseases in an Undergraduate Parasitology Course. JOURNAL OF MICROBIOLOGY & BIOLOGY EDUCATION 2021; 22:jmbe-22-4. [PMID: 33584946 PMCID: PMC7861210 DOI: 10.1128/jmbe.v22i1.2185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
Introducing undergraduate students to major human diseases is a key focus of many parasitology courses. Here I present a multifaceted active learning technique that familiarizes students with major human parasitic diseases while simultaneously exposing students to a range of important medical, biological, and ecological concepts.
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Affiliation(s)
- Carissa N Ganong
- Department of Biology, Missouri Western State University, St. Joseph, MO 64507
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18
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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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de Almeida M, Nascimento FS, Mathison BA, Bishop H, Bradbury RS, Cama VA, da Silva AJ. Duplex Real-Time PCR Assay for Clinical Differentiation of Onchocerca lupi and Onchocerca volvulus. Am J Trop Med Hyg 2020; 103:1556-1562. [PMID: 32748784 DOI: 10.4269/ajtmh.20-0113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the United States and Europe, human onchocerciasis is a rare disease caused by zoonotic or anthropophilic parasites in the genus Onchocerca. The zoonotic species identified in focal areas of Europe and United States is Onchocerca lupi, and Onchocerca volvulus, the anthroponotic species, may be found among people who had lived in endemic areas of Africa, the Arabian Peninsula, or Latin America. Onchocerciasis due to O. lupi is an emergent parasitic disease, with limited diagnostic methods, in addition to the lack of information on its biology, transmission, and epidemiology. Cutaneous nodules are the disease's most prevalent manifestation but lack diagnostic specificity. To address the diagnosis of onchocerciasis at reference laboratories, we developed a duplex TaqMan real-time PCR (qPCR) method, targeting the cytochrome oxidase subunit I locus which has species-specific probes to identify and differentiate O. lupi from O. volvulus. We determined the performance of the duplex with a panel of 45 samples: 11 positives for O. lupi, six for O. volvulus, five samples with negative results for Onchocerca spp., and 23 non-Onchocerca nematodes. The duplex qPCR correctly detected 10 of 11 O. lupi- and six of six O. volvulus-positive specimens. The new duplex assay allowed the simultaneous detection and discrimination of O. lupi and O. volvulus in clinical specimens, expediting and facilitating the clinical diagnosis of O. lupi in non-endemic settings where the disease is an infrequent finding.
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Affiliation(s)
- Marcos de Almeida
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Fernanda S Nascimento
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Blaine A Mathison
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Henry Bishop
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Richard S Bradbury
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Vitaliano A Cama
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alexandre J da Silva
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
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20
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Aza'ah RA, Sumo L, Ntonifor NH, Bopda J, Bamou RH, Nana-Djeunga HC. Point prevalence mapping reveals hotspot for onchocerciasis transmission in the Ndikinimeki Health District, Centre Region, Cameroon. Parasit Vectors 2020; 13:519. [PMID: 33066826 PMCID: PMC7565768 DOI: 10.1186/s13071-020-04387-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/06/2020] [Indexed: 11/10/2022] Open
Abstract
Background Ivermectin-based preventive chemotherapy (PC) is distributed annually to all at-risk populations eligible for ivermectin treatment to control and/or eliminate onchocerciasis. Information on the impact of mass ivermectin administration on onchocerciasis transmission is scanty, and it is tricky to appreciate the progress towards elimination and engage corrective measures. To fill that gap in the Centre Region in Cameroon, the current onchocerciasis endemicity level in the Ndikinimeki Health District after about two decades of mass treatments was assessed. Methods A cluster-based cross-sectional survey was carried out in the Ndikinimeki Health District and all volunteers aged ≥ 5 years were (i) interviewed on their compliance to ivermectin over the past five years and (ii) underwent clinical (nodule palpation and visual search for onchocercal lesions) and parasitological examinations (skin snip) for onchocerciasis. Results The overall Onchocerca volvulus prevalence was 7.0% (95% CI: 5.2–9.3%). The prevalence of the disease was significantly higher in the communities Kiboum 1 and Kiboum 2 compared to the other communities (highest prevalence in Makénéné Town Water: 8.5%; 95% CI: 2.3–20.4%) (χ2 = 51.314, df = 11, P = 0.0001). The proportion of systematic non-compliers to ivermectin was 23.3% (95% CI: 19.9–27.1%) among individuals interviewed. In the sentinel sites (Kiboum communities), onchocerciasis prevalence decreased from 95.2% (95% CI: 88.3–98.1%) to 23.7% (95% CI: 14.7–36.0%). Conclusions This study has revealed that the Ndikinimeki Health District is hypo-endemic for onchocerciasis after about two decades of preventive chemotherapy. However, transmission is ongoing, with potential hotspots in the Kiboum 1 and Kiboum 2 communities, which are known as first-line communities (closest to the breeding sites of the vector). Alternative or complementary strategies to annual ivermectin appear compulsory to accelerate the momentum towards onchocerciasis elimination.![]()
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Affiliation(s)
- René Afor Aza'ah
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon
| | - Laurentine Sumo
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon.
| | - Ngum Helen Ntonifor
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bambili, Cameroon
| | - Jean Bopda
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaounde, Cameroon
| | - Rolph H Bamou
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaounde, Cameroon
| | - Hugues C Nana-Djeunga
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaounde, Cameroon.
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21
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Milton P, Hamley JID, Walker M, Basáñez MG. Moxidectin: an oral treatment for human onchocerciasis. Expert Rev Anti Infect Ther 2020; 18:1067-1081. [PMID: 32715787 DOI: 10.1080/14787210.2020.1792772] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Moxidectin is a milbemycin endectocide recently approved for the treatment of human onchocerciasis. Onchocerciasis, earmarked for elimination of transmission, is a filarial infection endemic in Africa, Yemen, and the Amazonian focus straddling Venezuela and Brazil. Concerns over whether the predominant treatment strategy (yearly mass drug administration (MDA) of ivermectin) is sufficient to achieve elimination in all endemic foci have refocussed attention upon alternative treatments. Moxidectin's stronger and longer microfilarial suppression compared to ivermectin in both phase II and III clinical trials indicates its potential as a novel powerful drug for onchocerciasis elimination. AREAS COVERED This work summarizes the chemistry and pharmacology of moxidectin, reviews the phase II and III clinical trials evidence on tolerability, safety, and efficacy of moxidectin versus ivermectin, and discusses the implications of moxidectin's current regulatory status. EXPERT OPINION Moxidectin's superior clinical performance has the potential to substantially reduce times to elimination compared to ivermectin. If donated, moxidectin could mitigate the additional programmatic costs of biannual ivermectin distribution because, unlike other alternatives, it can use the existing community-directed treatment infrastructure. A pediatric indication (for children <12 years) and determination of its usefulness in onchocerciasis-loiasis co-endemic areas will greatly help fulfill the potential of moxidectin for the treatment and elimination of onchocerciasis.
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Affiliation(s)
- Philip Milton
- London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis (MRC GIDA), Department of Infectious Disease Epidemiology, Imperial College London , London, UK
| | - Jonathan I D Hamley
- London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis (MRC GIDA), Department of Infectious Disease Epidemiology, Imperial College London , London, UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis (MRC GIDA), Department of Infectious Disease Epidemiology, Imperial College London , London, UK.,London Centre for Neglected Tropical Disease Research, Department of Pathobiology and Population Sciences, Royal Veterinary College , Hatfield, UK
| | - María-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research and MRC Centre for Global Infectious Disease Analysis (MRC GIDA), Department of Infectious Disease Epidemiology, Imperial College London , London, UK
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22
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Khurana S, Sharma M. Parasitic keratitis - An under-reported entity. Trop Parasitol 2020; 10:12-17. [PMID: 32775286 PMCID: PMC7365502 DOI: 10.4103/tp.tp_84_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/12/2020] [Accepted: 01/20/2020] [Indexed: 11/04/2022] Open
Abstract
Parasitic keratitis (PK) is unique entity among parasitic infections where corneal involvement could result from direct inoculation of the parasite via exogenous environment or spread via endogenous neighboring organs or as a result of immune-mediated damage secondary to a systemic parasitic infection. Most cases of PK are caused by Acanthamoeba spp. and Microsporidia spp. though few other parasitic agents can also lead to corneal involvement. Mimicking as other infectious and non-infectious causes of keratitis, PK often escapes detection. This review summarizes the predominant causes of PK along with the epidemiological, clinical and microbiological details of each. Though several gaps exist in our understanding of the prevalence of PK, the one thing for sure is that PK is on the rise. With advanced diagnostic modalities and enough literature on optimal management of cases of PK, it is now imperative that a strong clinical suspicion of PK is kept when examining a case of corneal pathology and adequate investigations are ordered.
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Affiliation(s)
- Sumeeta Khurana
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Megha Sharma
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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23
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Otabil KB, Gyasi SF, Awuah E, Obeng-Ofori D, Tenkorang SB, Kessie JA, Schallig HDFH. Biting rates and relative abundance of Simulium flies under different climatic conditions in an onchocerciasis endemic community in Ghana. Parasit Vectors 2020; 13:229. [PMID: 32375902 PMCID: PMC7204027 DOI: 10.1186/s13071-020-04102-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 04/27/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Knowledge of the relative abundance and biting rates of riverine blackflies (vectors of onchocerciasis) is essential as these entomological indices affect transmission of the disease. However, transmission patterns vary from one ecological zone to another and this may be due to differences in species of blackfly vectors and the climatic conditions in the area. This study investigated the effects of climate variability on the relative abundance and biting rates of blackflies in the Tanfiano community (Nkoranza North District, Bono East Region, Ghana). Such information will help to direct policy on effective timing of the annual mass drug administration of ivermectin in the area. METHODS The study employed human landing collections and locally built Esperanza window traps to collect blackflies from March 2018 to February 2019. The relative abundance and biting rates of the Simulium vectors as well as the monthly climatic conditions of the study area were monitored. Correlation analysis and Poisson regression were used to establish the relationships between the variables. RESULTS The relative abundance and biting rates of the Simulium vectors were highest in the drier months of March, April and August, characterized by high temperatures, low humidity, longer hours of sunshine and stronger winds. The rainy months of May, June and July, characterized by low temperatures, high humidity, few hours of sunshine and weaker winds, had relatively low blackfly abundance and biting activity. Correlation analysis showed that only temperature was significantly, positively correlated with the relative abundance of blackflies (r = 0.617, n = 12, P = 0.033) and monthly biting rates (r = 0.612, n = 12, P = 0.034). A model to predict relative abundance and monthly biting rates using climatological variables was developed. CONCLUSIONS This study demonstrated that Simulium species in the study area preferred higher temperature, lower humidity and rainfall, more hours of sunshine and relatively stronger winds for survival. It is thus recommended that for the study district and others with similar climatological characteristics, mass drug administration of ivermectin should take place in April and September when the abundance of vectors has begun to decline after peaking.
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Affiliation(s)
- Kenneth Bentum Otabil
- Department of Basic and Applied Biology, School of Sciences, University of Energy and Natural Resources, Sunyani, BA, Ghana. .,Experimental Parasitology Unit, Department of Medical Microbiology, Academic Medical Centre, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
| | - Samuel Fosu Gyasi
- Department of Basic and Applied Biology, School of Sciences, University of Energy and Natural Resources, Sunyani, BA, Ghana
| | - Esi Awuah
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, AR, Ghana
| | - Daniels Obeng-Ofori
- Office of the Vice Chancellor, Catholic University College of Ghana, Sunyani, BA, Ghana
| | - Seth Boateng Tenkorang
- Faculty of Health and Allied Sciences, Koforidua Technical University, Koforidua, ER, Ghana
| | - Justice Amenyo Kessie
- Department of Mathematics and Statistics, University of Energy and Natural Resources, Sunyani, BA, Ghana
| | - Henk D F H Schallig
- Experimental Parasitology Unit, Department of Medical Microbiology, Academic Medical Centre, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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Ayalew F, Atnafu DD, Bedimo M, Mulatu K. Determinants of community-led ivermectin treatment adherence for onchocerciasis control in Western Ethiopia: a case-control study. Trop Med Health 2020; 48:22. [PMID: 32336928 PMCID: PMC7168851 DOI: 10.1186/s41182-020-00210-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/08/2020] [Indexed: 11/30/2022] Open
Abstract
Background Onchocerciasis is an infection of a filarial worm which is endemic in Sub-Saharan Africa, including Ethiopia. Annual mass treatment with high coverage over for a long period of time should lead to a complete interruption of transmission and the ultimate elimination of the parasite. However, in Ethiopia, the required coverage levels were not achieved. Thus, the aim of this study was to identify the possible determinants of onchocerciasis treatment adherence in Assossa District. Methods A case-control study was conducted among 528 respondents (176 cases and 352 controls). Cases were respondents who took all five doses of treatments, and controls were those who took at most four does of ivermectin treatments (missed at least one or more doses). Structured questionnaire was used for data collection. Each possible factor for treatment adherence, with a P value < 0.2 obtained in the bi-variable logistic regression was entered into the multivariable logistic regression models to control the confounding factors. p value < 0.05 was used as cut-off-point for a variable to become a significant determinant of treatment adherence in multivariable logistic regression. Results Participation in selecting drug distributers [AOR = 2.7, 95%CI (1.7–4.1)], measuring height for dose determination [AOR = 3.6, 95%CI (1.9–6.7)], perceived risk of getting onchocerciasis [AOR = 2.1, 95%CI (1.6–2.7)], living near running water [AOR = 1.7, 95%CI (1.1–2.8)], and perceived needs of support for intake of ivermectin [AOR = 3.2, 95%CI(2.1–4.9)] were independent predictors for t treatment adherence. Conclusions Treatment adherence was influenced by participation in selecting drug distributers, measuring height for dose determination, perceived risk of getting onchocerciasis, living near running water and perceived needs of support for intake of ivermectin. To improve intake of the drug and its adherence, the community should be empowered to make decisions, and counseling family members and sensitizing those living far from river sides is commendable. Health information about onchocerciasis should be strengthening to increase risk perception.
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Affiliation(s)
- Fikadu Ayalew
- 1School of Public Health, College of Medicine and Health Science, Bahir Dar University, Bahir Dar, Ethiopia
| | - Desta Debalkie Atnafu
- 2Department of Health System and Health Economics, School of Public Health, College of Medicine and Health Science, Bahir Dar University, Bahir Dar, Ethiopia
| | - Melkamu Bedimo
- 3Department of Epidemiology and Biostatistics, School of Public Health, College of Medicine and Health Science, Bahir Dar University, Bahir Dar, Ethiopia
| | - Kebadnew Mulatu
- 3Department of Epidemiology and Biostatistics, School of Public Health, College of Medicine and Health Science, Bahir Dar University, Bahir Dar, Ethiopia
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Makenga Bof JC, Muteba D, Mansiangi P, Ilunga-Ilunga F, Coppieters Y. Analysis of severe adverse effects following community-based ivermectin treatment in the Democratic Republic of Congo. BMC Pharmacol Toxicol 2019; 20:49. [PMID: 31420005 PMCID: PMC6697993 DOI: 10.1186/s40360-019-0327-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 07/23/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The progress of mass, community-directed, treatment with ivermectin (CDTI) for onchocerciasis control was disrupted by severe adverse effects (SAE) in the Democratic Republic of Congo (DRC). The study aimed at determining the frequency of post-CDTI SAE as well as factors associated with the occurrence of SAE. METHODS Our retrospective study relied on SAE collection cards, as archived by the DRC Ministry of Health, and compiled for people who benefited from ivermectin treatment then further developed SAE. The study included 945 post-CDTI SAE recorded in DRC between 2003 and 2017. These cases occurred in 15 projects out of 22 projects implemented in the country. All cards were reviewed and analysed. RESULTS Between the years 2003 and 2017, the total average population treated was around 15,552,588 among which 945 cases of SAE were registered in DR Congo, i.e. 6 cases of SAE for 100,000 persons treated per year. 55 deaths related to post-CDTI SAE were recorded, which represents 5.8% of all cases of SAE. Non-neurological SAE were dominated by severe headaches (74.8%), myalgia (64.0%) and arthralgia (62.7%). Neurological SAE were mainly coma (94.1%), motor deficit (75.4%) and palpebral subconjunctival haemorrhages (38.8%). Factors associated with the occurrence of SAE were: male, age over 18 years old, alcohol consumption, hemp intake and the presence of loiasis. The study also highlighted weaknesses of the National Program for Onchocerciasis Control (NPOC) in terms of awareness campaigns among the population. CONCLUSION Co-endemicity of loiasis and onchocerciasis is one of the key factors responsible for the occurrence of SAE following ivermectin treatment. Mobilization of resources necessary to the appropriate management of SAE and awareness of populations are essential to achieve onchocerciasis control in DRC.
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Affiliation(s)
- Jean-Claude Makenga Bof
- School of Public Health, Université Libre de Bruxelles (ULB), Route de Lennik numéro 808 à 1070, Brussels, Belgium
| | - Daniel Muteba
- National Program for Onchocerciasis Control (NPOC), Kinshasa, Gombe Democratic Republic of Congo
| | - Paul Mansiangi
- School of Public Health, Faculty of Medicine, Université de Kinshasa (UNIKIN), Route de Kimwenza, Lemba Kinshasa, Democratic Republic of Congo
| | - Félicien Ilunga-Ilunga
- School of Public Health, Université Libre de Bruxelles (ULB), Route de Lennik numéro 808 à 1070, Brussels, Belgium
- Institut Supérieur des Techniques Médicales (ISTM), Route de Kimwenza, Lemba Kinshasa, Democratic Republic of Congo
| | - Yves Coppieters
- School of Public Health, Université Libre de Bruxelles (ULB), Route de Lennik numéro 808 à 1070, Brussels, Belgium
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Gebrezgabiher G, Mekonnen Z, Yewhalaw D, Hailu A. Reaching the last mile: main challenges relating to and recommendations to accelerate onchocerciasis elimination in Africa. Infect Dis Poverty 2019; 8:60. [PMID: 31269966 PMCID: PMC6609392 DOI: 10.1186/s40249-019-0567-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 06/10/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Onchocerciasis (river blindness), caused by the filarial worm species Onchocerca volvulus, is a serious vector-borne neglected tropical disease (NTD) of public health and socioeconomic concern. It is transmitted through the bite of black flies of the genus Simulium, and manifested in dermal and ocular lesions. Ninety-nine percent of the total global risk and burden of onchocerciasis is in Africa. This scoping review examines the key challenges related to the elimination of onchocerciasis by 2020-2025 in Africa, and proposes recommendations to overcome the challenges and accelerate disease elimination. To find relevant articles published in peer-reviewed journals, a search of PubMed and Google Scholar databases was carried out. MAIN TEXT Rigorous regional interventions carried out to control and eliminate onchocerciasis in the past four decades in Africa have been effective in bringing the disease burden under control; it is currently not a public health problem in most endemic areas. Notably, transmission of the parasite is interrupted in some hyperendemic localities. Recently, there has been a policy shift from control to complete disease elimination by 2020 in selected countries and by 2025 in the majority of endemic African countries. The WHO has published guidelines for stopping mass drug administration (MDA) and verifying the interruption of transmission and elimination of human onchocerciasis. Therefore, countries have revised their plans, established a goal of disease elimination in line with an evidence based decision to stop MDA and verify elimination, and incorporated it into their NTDs national master plans. Nevertheless, challenges remain pertaining to the elimination of onchocerciasis in Africa. The challenge we review in this paper are: incomplete elimination mapping of all transmission zones, co-endemicity of onchocerciasis and loiasis, possible emergence of ivermectin resistance, uncoordinated cross-border elimination efforts, conflict and civil unrest, suboptimal program implementation, and technical and financial challenges. This paper also proposes recommendations to overcome the challenges and accelerate disease elimination. These are: a need for complete disease elimination mapping, a need for collaborative elimination activities between national programs, a need for a different drug distribution approach in conflict-affected areas, a need for routine monitoring and evaluation of MDA programs, a need for implementing alternative treatment strategies (ATSs) in areas with elimination anticipated beyond 2025, and a need for strong partnerships and continued funding. CONCLUSIONS National programs need to regularly monitor and evaluate the performance and progress of their interventions, while envisaging the complete elimination of onchocerciasis from their territory. Factors hindering the targeted goal of interruption of parasite transmission need to be identified and remedial actions should be taken. If possible and appropriate, ATSs need to be implemented to accelerate disease elimination by 2025.
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Affiliation(s)
- Gebremedhin Gebrezgabiher
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
- College of Veterinary Medicine, Samara University, Samara, Ethiopia
| | - Zeleke Mekonnen
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Institute of Health Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Turner HC, Walker M, Pion SDS, McFarland DA, Bundy DAP, Basáñez M. Economic evaluations of onchocerciasis interventions: a systematic review and research needs. Trop Med Int Health 2019; 24:788-816. [PMID: 31013395 PMCID: PMC6617745 DOI: 10.1111/tmi.13241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To provide a systematic review of economic evaluations that has been conducted for onchocerciasis interventions, to summarise current key knowledge and to identify research gaps. METHOD A systematic review of the literature was conducted on the 8th of August 2018 using the PubMed (MEDLINE) and ISI Web of Science electronic databases. No date or language stipulations were applied to the searches. RESULTS We identified 14 primary studies reporting the results of economic evaluations of onchocerciasis interventions, seven of which were cost-effectiveness analyses. The studies identified used a variety of different approaches to estimate the costs of the investigated interventions/programmes. Originally, the studies only quantified the benefits associated with preventing blindness. Gradually, methods improved and also captured onchocerciasis-associated skin disease. Studies found that eliminating onchocerciasis would generate billions in economic benefits. The majority of the cost-effectiveness analyses evaluated annual mass drug administration (MDA). The estimated cost per disability-adjusted life year (DALY) averted of annual MDA varies between US$3 and US$30 (cost year variable). CONCLUSIONS The cost benefit and cost effectiveness of onchocerciasis interventions have consistently been found to be very favourable. This finding provides strong evidential support for the ongoing efforts to eliminate onchocerciasis from endemic areas. Although these results are very promising, there are several important research gaps that need to be addressed as we move towards the 2020 milestones and beyond.
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Affiliation(s)
- Hugo C. Turner
- Oxford University Clinical Research UnitWellcome Africa Asia ProgrammeHo Chi Minh CityVietnam
- Centre for Tropical Medicine and Global HealthNuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Martin Walker
- London Centre for Neglected Tropical Disease ResearchDepartment of Pathobiology and Population SciencesRoyal Veterinary CollegeHatfieldUK
- London Centre for Neglected Tropical Disease ResearchDepartment of Infectious Disease EpidemiologySchool of Public HealthImperial College LondonLondonUK
| | - Sébastien D. S. Pion
- Institut de Recherche pour le DéveloppementUMI 233‐INSERMU1175‐Montpellier UniversityMontpellierFrance
| | | | | | - María‐Gloria Basáñez
- London Centre for Neglected Tropical Disease ResearchDepartment of Infectious Disease EpidemiologySchool of Public HealthImperial College LondonLondonUK
- MRC Centre for Global Infectious Disease AnalysisDepartment of Infectious Disease EpidemiologySchool of Public HealthImperial College LondonLondonUK
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Williams HF, Layfield HJ, Vallance T, Patel K, Bicknell AB, Trim SA, Vaiyapuri S. The Urgent Need to Develop Novel Strategies for the Diagnosis and Treatment of Snakebites. Toxins (Basel) 2019; 11:E363. [PMID: 31226842 PMCID: PMC6628419 DOI: 10.3390/toxins11060363] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023] Open
Abstract
Snakebite envenoming (SBE) is a priority neglected tropical disease, which kills in excess of 100,000 people per year. Additionally, many millions of survivors also suffer through disabilities and long-term health consequences. The only treatment for SBE, antivenom, has a number of major associated problems, not least, adverse reactions and limited availability. This emphasises the necessity for urgent improvements to the management of this disease. Administration of antivenom is too frequently based on symptomatology, which results in wasting crucial time. The majority of SBE-affected regions rely on broad-spectrum polyvalent antivenoms that have a low content of case-specific efficacious immunoglobulins. Research into small molecular therapeutics such as varespladib/methyl-varespladib (PLA2 inhibitors) and batimastat/marimastat (metalloprotease inhibitors) suggest that such adjunctive treatments could be hugely beneficial to victims. Progress into toxin-specific monoclonal antibodies as well as alternative binding scaffolds such as aptamers hold much promise for future treatment strategies. SBE is not implicit during snakebite, due to venom metering. Thus, the delay between bite and symptom presentation is critical and when symptoms appear it may often already be too late to effectively treat SBE. The development of reliable diagnostical tools could therefore initiate a paradigm shift in the treatment of SBE. While the complete eradication of SBE is an impossibility, mitigation is in the pipeline, with new treatments and diagnostics rapidly emerging. Here we critically review the urgent necessity for the development of diagnostic tools and improved therapeutics to mitigate the deaths and disabilities caused by SBE.
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Affiliation(s)
| | | | - Thomas Vallance
- School of Pharmacy, University of Reading, Reading RG6 6AH, UK.
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
| | - Andrew B Bicknell
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
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Short-course, oral flubendazole does not mediate significant efficacy against Onchocerca adult male worms or Brugia microfilariae in murine infection models. PLoS Negl Trop Dis 2019; 13:e0006356. [PMID: 30650071 PMCID: PMC6334903 DOI: 10.1371/journal.pntd.0006356] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/28/2018] [Indexed: 01/15/2023] Open
Abstract
The Onchocerca ochengi adult implant and Brugia malayi microfilariemic Severe-Combined Immunodeficient (SCID) mouse models are validated screens to measure macrofilaricidal and microfilaricidal activities of candidate onchocerciasis drugs. The purpose of this study was to assess whether 5 daily sub-cutaneous (s.c.) injections of standard flubendazole (FBZ) suspension (10mg/kg), a single s.c. injection (10mg/kg) or 5 daily repeated oral doses of FBZ amorphous solid dispersion (ASD) formulation (0.2, 1.5 or 15mg/kg) mediated macrofilaricidal efficacy against O. ochengi male worms implanted into SCID mice. The direct microfilaricidal activity against circulating B. malayi microfilariae of single dose FBZ ASD formulation (2 or 40 mg/kg) was also evaluated and compared against the standard microfilaricide, ivermectin (IVM). Systemic exposures of FBZ/FBZ metabolites achieved following dosing were measured by pharmacokinetic (PK) bioanalysis. At necropsy, five weeks following start of FBZ SC injections, there were significant reductions in burdens of motile O. ochengi worms following multiple injections (93%) or single injection (82%). Further, significant proportions of mice dosed following multiple injections (5/6; 83%) or single injection (6/10; 60%) were infection negative (drug-cured). In comparison, no significant reduction in recovery of motile adult O. ochengi adult worms was obtained in any multiple-oral dosage group. Single oral-dosed FBZ did not mediate any significant microfilaricidal activity against circulating B. malayi mf at 2 or 7 days compared with >80% efficacy of single dose IVM. In conclusion, multiple oral FBZ formulation doses, whilst achieving substantial bioavailability, do not emulate the efficacy delivered by the parenteral route in vivo against adult O. ochengi. PK analysis determined FBZ efficacy was related to sustained systemic drug levels rather than achievable Cmax. PK modelling predicted that oral FBZ would have to be given at low dose for up to 5 weeks in the mouse model to achieve a matching efficacious exposure profile.
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Koala L, Nikièma AS, Paré AB, Drabo F, Toé LD, Belem AMG, Boakye DA, Traoré S, Dabiré RK. Entomological assessment of the transmission following recrudescence of onchocerciasis in the Comoé Valley, Burkina Faso. Parasit Vectors 2019; 12:34. [PMID: 30646934 PMCID: PMC6332526 DOI: 10.1186/s13071-019-3290-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 01/03/2019] [Indexed: 11/10/2022] Open
Abstract
Background Onchocerciasis, or river blindness, is a dermal filariasis caused by infection with the nematode parasite Onchocerca volvulus, transmitted to humans through the bites of blackflies of the genus Simulium. Despite the decade-long West African Regional Programme for the Elimination of Onchocerciasis, involving the mass administration of ivermectin to populations in endemic areas, recrudescence has occurred. An example is in the Cascades Region of south-west Burkina Faso where the resumption of transmission had resulted in infection prevalences of up to 70% in some villages. In 2011, a strategy for community-directed distribution of ivermectin (CDTI) was set up to respond to this worrying re-emergence. Here, we report on a study of Onchocerca spp. transmission in the affected area carried out from January to December 2012. Every month, host-seeking adult females of the S. damnosum complex were collected at sites on the River Comoé near the four villages (Bodadiougou, Bolibana, Badara Karaboro and Badara Dogossè) that had recorded the highest prevalences in 2010. Collected blackflies were dissected and infective larvae were identified using the O-150 PCR method. Results A total of 9114 S. damnosum (s.l.) adult females were collected, of which 5142 were parous (56.4%) and 78 (1.51%) were infective carrying a total of 137 infective larvae. The annual transmission potential (ATP) was calculated as 0, 30, 255 and 771 infective larvae/man/year in Badara Dogossè, Bolibana, Badara Karaboro and Bodadiougou, respectively. Transmission levels in the latter two are of particular concern as they were higher than 100 infective larvae/person/year, the designated minimum threshold required for elimination of severe pathology, including damage to vision. Conclusions These results confirm that recrudescence of onchocerciasis has occurred, and that transmission of O. volvulus was active at sites on the Comoé River in the Cascades region in 2012. In accordance with WHO recommendations, CDTI should be continued and the situation in the Cascades region should be closely monitored if further spread of this outbreak is to be avoided. Electronic supplementary material The online version of this article (10.1186/s13071-019-3290-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lassane Koala
- Ministère de l'Enseignement Supérieur, de la Recherche Scientifique et de l'Innovation, Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, BP 545, Bobo Dioulasso 01, Burkina Faso.
| | - Achille S Nikièma
- Ministère de l'Enseignement Supérieur, de la Recherche Scientifique et de l'Innovation, Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, BP 545, Bobo Dioulasso 01, Burkina Faso
| | - Alain B Paré
- Ministère de la Santé, Direction Générale de la Santé, BP 7003, Ouagadougou 01, Burkina Faso
| | - François Drabo
- Ministère de la Santé, Direction Générale de la Santé, BP 7003, Ouagadougou 01, Burkina Faso
| | - Laurent D Toé
- WHO/AFRO/ESPEN Laboratory, Ouagadougou, Burkina Faso
| | - Adrien M G Belem
- Université Nazi Boni de Bobo-Dioulasso 01, BP 1091, Bobo-Dioulasso, Burkina Faso
| | | | | | - Roch K Dabiré
- Ministère de l'Enseignement Supérieur, de la Recherche Scientifique et de l'Innovation, Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, BP 545, Bobo Dioulasso 01, Burkina Faso
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The Search for an Efficient Black Fly Trap for Xenomonitoring of Onchocerciasis. J Parasitol Res 2018; 2018:5902367. [PMID: 30057801 PMCID: PMC6051068 DOI: 10.1155/2018/5902367] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/21/2018] [Accepted: 05/26/2018] [Indexed: 11/18/2022] Open
Abstract
Onchocerciasis is a neglected tropical disease that has plagued mankind for decades with pathologies that involve the eyes and the skin. The WHO and the global health community have earmarked the disease for global elimination by 2045. However, as control programmes shift focus from reduction of the burden of the disease to elimination, new tools and strategies may be needed to meet targets. Monitoring Onchocerca volvulus larvae in the black fly vectors is an important tool needed to monitor disease dynamics and certify elimination. For decades, human landing collections have been the sole means of acquiring vectors for monitoring of the disease. This procedure has been plagued with ethical concerns and sometimes the inability to harvest enough black flies needed to carry out effective monitoring. Since the 1960s, the WHO recognized the need to replace human landing collections but relatively few field studies have designed and tested alternative traps. This review article systematically discusses some of the key traps tested, their successes, and their challenges. It is the aim of the review to direct research and development focus to the most successful and promising vector traps which could potentially replace the human landing collections.
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Routledge I, Walker M, Cheke RA, Bhatt S, Nkot PB, Matthews GA, Baleguel D, Dobson HM, Wiles TL, Basañez MG. Modelling the impact of larviciding on the population dynamics and biting rates of Simulium damnosum (s.l.): implications for vector control as a complementary strategy for onchocerciasis elimination in Africa. Parasit Vectors 2018; 11:316. [PMID: 29843770 PMCID: PMC5972405 DOI: 10.1186/s13071-018-2864-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/23/2018] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND In 2012, the World Health Organization set goals for the elimination of onchocerciasis transmission by 2020 in selected African countries. Epidemiological data and mathematical modelling have indicated that elimination may not be achieved with annual ivermectin distribution in all endemic foci. Complementary and alternative treatment strategies (ATS), including vector control, will be necessary. Implementation of vector control will require that the ecology and population dynamics of Simulium damnosum (sensu lato) be carefully considered. METHODS We adapted our previous SIMuliid POPulation dynamics (SIMPOP) model to explore the impact of larvicidal insecticides on S. damnosum (s.l.) biting rates in different ecological contexts and to identify how frequently and for how long vector control should be continued to sustain substantive reductions in vector biting. SIMPOP was fitted to data from large-scale aerial larviciding trials in savannah sites (Ghana) and small-scale ground larviciding trials in forest areas (Cameroon). The model was validated against independent data from Burkina Faso/Côte d'Ivoire (savannah) and Bioko (forest). Scenario analysis explored the effects of ecological and programmatic factors such as pre-control daily biting rate (DBR) and larviciding scheme design on reductions and resurgences in biting rates. RESULTS The estimated efficacy of large-scale aerial larviciding in the savannah was greater than that of ground-based larviciding in the forest. Small changes in larvicidal efficacy can have large impacts on intervention success. At 93% larvicidal efficacy (a realistic value based on field trials), 10 consecutive weekly larvicidal treatments would reduce DBRs by 96% (e.g. from 400 to 16 bites/person/day). At 70% efficacy, and for 10 weekly applications, the DBR would decrease by 67% (e.g. from 400 to 132 bites/person/day). Larviciding is more likely to succeed in areas with lower water temperatures and where blackfly species have longer gonotrophic cycles. CONCLUSIONS Focal vector control can reduce vector biting rates in settings where a high larvicidal efficacy can be achieved and an appropriate duration and frequency of larviciding can be ensured. Future work linking SIMPOP with onchocerciasis transmission models will permit evaluation of the impact of combined anti-vectorial and anti-parasitic interventions on accelerating elimination of the disease.
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Affiliation(s)
- Isobel Routledge
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA UK
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
| | - Robert A. Cheke
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
- Natural Resources Institute, Department of Agriculture, Health & Environment, University of Greenwich, Central Avenue, Chatham Maritime, Chatham, Kent, ME4 4TB UK
| | - Samir Bhatt
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
| | | | - Graham A. Matthews
- Yaoundé Initiative Foundation, Department of Life Sciences, Faculty of Natural Sciences (Silwood Park), Imperial College London, Ascot, Berkshire SL5 7PY UK
| | - Didier Baleguel
- Yaoundé Initiative Foundation, P.O. Box 3878, Messa, Yaoundé, Cameroon
| | - Hans M. Dobson
- Natural Resources Institute, Department of Agriculture, Health & Environment, University of Greenwich, Central Avenue, Chatham Maritime, Chatham, Kent, ME4 4TB UK
| | - Terry L. Wiles
- Yaoundé Initiative Foundation, P.O. Box 3878, Messa, Yaoundé, Cameroon
- Yaoundé Initiative Foundation, Department of Life Sciences, Faculty of Natural Sciences (Silwood Park), Imperial College London, Ascot, Berkshire SL5 7PY UK
| | - Maria-Gloria Basañez
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s campus), Imperial College London, Norfolk Place, London, W2 1PG UK
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Koroma JB, Sesay S, Conteh A, Koudou B, Paye J, Bah M, Sonnie M, Hodges MH, Zhang Y, Bockarie MJ. Impact of five annual rounds of mass drug administration with ivermectin on onchocerciasis in Sierra Leone. Infect Dis Poverty 2018; 7:30. [PMID: 29628019 PMCID: PMC5890354 DOI: 10.1186/s40249-018-0410-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 03/20/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Onchocerciasis is endemic in 12 of the 14 health districts of Sierra Leone. Good treatment coverage of community-directed treatment with ivermectin was achieved between 2005 and 2009 after the 11-year civil conflict. Sentinel site surveys were conducted in 2010 to evaluate the impact of five annual rounds of ivermectin distribution. METHODS In total, 39 sentinel villages from hyper- and meso-endemic areas across the 12 endemic districts were surveyed using skin snips in 2010. Results were analyzed and compared with the baseline data from the same 39 villages. RESULTS The average microfilaridermia (MF) prevalence across 39 sentinel villages was 53.10% at baseline. The MF prevalence was higher in older age groups, with the lowest in the age group of 1-9 years (11.00%) and the highest in the age group of 40-49 years (82.31%). Overall mean MF density among the positives was 28.87 microfilariae (mf)/snip, increasing with age with the lowest in the age group of 1-9 years and the highest in the age group of 40-49 years. Males had higher MF prevalence and density than females. In 2010 after five rounds of mass drug administration, the overall MF prevalence decreased by 60.26% from 53.10% to 21.10%; the overall mean MF density among the positives decreased by 71.29% from 28.87 mf/snip to 8.29 mf/snip; and the overall mean MF density among all persons examined decreased by 88.58% from 15.33 mf/snip to 1.75 mf/snip. Ten of 12 endemic districts had > 50% reduction in MF prevalence. Eleven of 12 districts had ≥50% reduction in mean MF density among the positives. CONCLUSIONS A significant reduction of onchocerciasis MF prevalence and mean density was recorded in all 12 districts of Sierra Leone after five annual MDAs with effective treatment coverage. The results suggested that the onchocerciasis elimination programme in Sierra Leone was on course to reach the objective of eliminating onchocerciasis in the country by the year 2025. Annual MDA with ivermectin should continue in all 12 districts and further evaluations are needed across the country to assist the NTDP with programme decision making.
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Affiliation(s)
- Joseph B. Koroma
- Family Health International (FHI) 360, Ghana Country Office, Accra, Ghana
| | - Santigie Sesay
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Abdul Conteh
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Benjamin Koudou
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jusufu Paye
- Helen Keller International, Freetown, Sierra Leone
| | - Mohamed Bah
- Helen Keller International, Freetown, Sierra Leone
| | | | | | - Yaobi Zhang
- Helen Keller International, Regional Office for Africa, Dakar, Senegal
| | - Moses J. Bockarie
- European & Developing Countries Clinical Trials Partnership (EDCTP), Medical Research Council, Cape Town, South Africa
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Komlan K, Vossberg PS, Gantin RG, Solim T, Korbmacher F, Banla M, Padjoudoum K, Karabou P, Köhler C, Soboslay PT. Onchocerca volvulus infection and serological prevalence, ocular onchocerciasis and parasite transmission in northern and central Togo after decades of Simulium damnosum s.l. vector control and mass drug administration of ivermectin. PLoS Negl Trop Dis 2018; 12:e0006312. [PMID: 29494606 PMCID: PMC5849363 DOI: 10.1371/journal.pntd.0006312] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 03/13/2018] [Accepted: 02/12/2018] [Indexed: 11/18/2022] Open
Abstract
Background Mass drug administration (MDA) of ivermectin has become the main intervention to control onchocerciasis or “river blindness”. In Togo, after many years of MDA, Onchocerca volvulus infection has declined dramatically, and elimination appears achievable, but in certain river basins the current situation remains unknown. We have conducted parasitological, serological, ophthalmological, and entomological assessments in northern and central Togo within the river basins of Ôti, Kéran and Mô. Methodology/Principal findings Examinations were completed in 1,455 participants from 11 onchocerciasis sentinel villages, and O. volvulus transmission by Simulium damnosum sensu lato (s.l.) was evaluated. In children (aged 1–10 years), the prevalence of microfilariae (Mf) was 2.3% and in adults it ranged from 5.1 to 13.3%. Positive IgG4 responses to O. volvulus adult (crude) worm antigen (OvAg) and the recombinant Ov16 antigen were in all-ages 48.7% and 34.4%, and 29.1% and 14.9% in children, respectively. In the river basin villages of Kéran, Mô and Ôti, the IgG4 seroprevalences to OvAg in children were 51.7%, 23.5% and 12.7%, respectively, and to the Ov16 antigen 33.3% (Kéran) and 5.2% (Ôti). Onchocerciasis ocular lesions (punctate keratitis, evolving iridocyclitis and chorioretinitis) were observed in children and young adults. O. volvulus-specific DNA (Ov150) was detected by poolscreen in vector samples collected from Tchitchira/Kéran(22.8%), Bouzalo/Mô(11.3%), Baghan/Mô(2.9%) and Pancerys/Ôti(4.9%); prevalences of O. volvulus infection in S. damnosum s.l. were, respectively, 1%, 0.5%, 0.1% and 0.2%. Conclusions/Significance In the northern and central river basins in Togo, interruption of O. volvulus transmission has not yet been attained. Patent O. volvulus infections, positive antibody responses, progressive ocular onchocerciasis were diagnosed, and parasite transmission by S. damnosum s.l. occurred close to the survey locations. Future interventions may require approaches selectively targeted to non-complying endemic populations, to the seasonality of parasite transmission and national onchocerciasis control programs should harmonize cross-border MDA as a coordinated intervention. Mass drug administration (MDA) with ivermectin has become the main tool in the efforts to control and eliminate onchocerciasis (“river blindness”). In some areas, and after many years of MDA, levels of Onchocerca volvulus infection (the causative parasite) have declined greatly, and elimination appears achievable. In certain river basins of northern and central Togo, the present epidemiological situation remains unknown. The guidelines of the World Health Organization recommend that before ivermectin MDA can be stopped, interruption of O. volvulus transmission must be demonstrated. To this end, parasitological, serological, ophthalmological, and entomological assessments were conducted in the Ôti, Kéran and Mô river basins. O. volvulus infections and positive antibody responses were found in children aged ≤10 years and adults. Progressive ocular onchocerciasis was diagnosed, and parasite transmission by Simulium damnosum s.l. (the disease vector) occurred close to the survey locations. Thus, O. volvulus transmission continues in northern and central Togo, and future interventions may require approaches selectively adapted to seasonal migration of non-complying endemic populations in and out of the river basins, as well as seasonal transmission by the vectors. National control programmes should harmonize cross-border MDA as a coordinated intervention.
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Affiliation(s)
- Kossi Komlan
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Patrick S. Vossberg
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Richard G. Gantin
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Tchalim Solim
- Centre Hospitalier Universitaire Campus, Université de Lomé, Lomé, Togo
| | - Francois Korbmacher
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Méba Banla
- Centre Hospitalier Universitaire Campus, Université de Lomé, Lomé, Togo
| | | | | | - Carsten Köhler
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
| | - Peter T. Soboslay
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
- Institute for Tropical Medicine, University of Tübingen, University Clinics, Tübingen, Germany
- * E-mail:
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Colebunders R, Nelson Siewe FJ, Hotterbeekx A. Onchocerciasis-Associated Epilepsy, an Additional Reason for Strengthening Onchocerciasis Elimination Programs. Trends Parasitol 2017; 34:208-216. [PMID: 29288080 DOI: 10.1016/j.pt.2017.11.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 10/18/2022]
Abstract
A high prevalence of epilepsy has been observed in onchocerciasis-endemic regions with high onchocerciasis transmission. Recent epidemiological studies suggest that Onchocerca volvulus infection is the trigger causing the seizures, which appear in previously healthy children between the ages of 3 and 18 years. Persons with onchocerciasis-associated epilepsy present with a wide spectrum of seizures, including atonic and myoclonic neck seizures; but also absences and most frequently generalized tonic-clonic seizures. Often individuals present with intellectual disabilities and psychiatric disorders and occasionally with 'Nakalanga' features such as severe stunting with delayed or absent external signs of sexual development. Onchocerciasis-associated epilepsy, because of its importance as a public health problem, is an additional reason for strengthening onchocerciasis elimination programs.
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Affiliation(s)
| | - F J Nelson Siewe
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - An Hotterbeekx
- Global Health Institute, University of Antwerp, Antwerp, Belgium
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Puente S, Ramirez-Olivencia G, Lago M, Subirats M, Perez-Blazquez E, Bru F, Garate T, Vicente B, Belhassen-Garcia M, Muro A. Dermatological manifestations in onchocerciasis: A retrospective study of 400 imported cases. Enferm Infecc Microbiol Clin 2017; 36:633-639. [PMID: 29275076 DOI: 10.1016/j.eimc.2017.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Onchocerciasis is caused by Onchocerca volvulus and mainly leads to pruritus and skin and visual disorders, including blindness. Seventeen million people are infected in 38 countries; 31 of these are in sub-Saharan Africa, six in Latin America and one on the Arabian Peninsula. More than 99% of cases occur in sub-Saharan Africa where 120 million people are at risk of infection. Eye disorders have been well-documented; however, skin disorders have not been described accurately. The objective of our study was to describe the epidemiology, main skin manifestations and treatment of imported onchocerciasis. MATERIAL AND METHODS A retrospective study was thus conducted by analysing the main demographic, clinical and treatment data regarding a cohort of 400 patients attending a reference clinical unit over a 17-year period. RESULTS Most patients were female (55%) with mean age 37.5±16.7 years. All the migrants came from sub-Saharan countries. The most frequently occurring dermatological symptom was pruritus. Ivermectin had been used as first-line therapy and adverse reactions had been described in 11 patients (3.2%). CONCLUSIONS The results indicate the fact that there should be a clinical suspicion of onchocerciasis regarding immigrants from endemic areas having skin lesions compatible with the disease's profile or asymptomatic patients having eosinophilia or unexplained high IgE. Moreover, skin snips from the buttocks region were very fruitful and treatment with ivermectin was seen to be safe. This is the largest case series regarding imported onchocerciasis described up to the present time.
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Affiliation(s)
- Sabino Puente
- Unidad de Medicina Tropical, Servicio de Medicina Interna, Hospital La Paz-Carlos III, Madrid, Spain
| | - German Ramirez-Olivencia
- Unidad de Aislamiento de Alto Nivel, Sección de Enfermedades Infecciosas, Servicio de Medicina Interna, Hospital Central de la Defensa Gómez Ulla, Madrid, Spain
| | - Mar Lago
- Unidad de Medicina Tropical, Servicio de Medicina Interna, Hospital La Paz-Carlos III, Madrid, Spain
| | | | - Eugenio Perez-Blazquez
- Servicio de Oftalmología, Hospital Universitario 12 de Octubre, Universidad complutense de Madrid, Spain
| | | | - Teresa Garate
- Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Belén Vicente
- Laboratorio de Inmunología Parasitaria y Molecular, CIETUS, IBSAL, Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
| | - Moncef Belhassen-Garcia
- Servicio de Medicina Interna, Sección de Enfermedades Infecciosas, CAUSA, IBSAL, CIETUS, Universidad de Salamanca, Salamanca, Spain
| | - Antonio Muro
- Laboratorio de Inmunología Parasitaria y Molecular, CIETUS, IBSAL, Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain.
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Palioura S, Kymionis G. Corneal neovascularization in childhood keratitis. EXPERT REVIEW OF OPHTHALMOLOGY 2017. [DOI: 10.1080/17469899.2017.1379900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Sotiria Palioura
- Athens Vision Eye Institute, Cornea Service, Athens, Greece
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - George Kymionis
- Jules Gonin Eye Hospital, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Ophthalmology, ‘Gennimatas Hospital’, National and Kapoditrian University of Athens, Athens, Greece
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Kearns TM, Currie BJ, Cheng AC, McCarthy J, Carapetis JR, Holt DC, Page W, Shield J, Gundjirryirr R, Mulholland E, Ward L, Andrews RM. Strongyloides seroprevalence before and after an ivermectin mass drug administration in a remote Australian Aboriginal community. PLoS Negl Trop Dis 2017; 11:e0005607. [PMID: 28505198 PMCID: PMC5444847 DOI: 10.1371/journal.pntd.0005607] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 05/25/2017] [Accepted: 04/27/2017] [Indexed: 01/01/2023] Open
Abstract
Background Strongyloides seroprevalence is hyper-endemic in many Australian Aboriginal and Torres Strait Islander communities, ranging from 35–60%. We report the impact on Strongyloides seroprevalence after two oral ivermectin mass drug administrations (MDAs) delivered 12 months apart in a remote Australian Aboriginal community. Methods Utilizing a before and after study design, we measured Strongyloides seroprevalence through population census with sequential MDAs at baseline and month 12. Surveys at months 6 and 18 determined changes in serostatus. Serodiagnosis was undertaken by ELISA that used sonicated Strongyloides ratti antigen to detect anti-Strongyloides IgG. Non-pregnant participants weighing ≥15 kg were administered a single 200 μg/kg ivermectin dose, repeated after 10–42 days if Strongyloides and/or scabies was diagnosed; others followed a standard alternative algorithm. A questionnaire on clinical symptoms was administered to identify adverse events from treatment and self-reported symptoms associated with serostatus. Findings We surveyed 1013 participants at the baseline population census and 1060 (n = 700 from baseline cohort and 360 new entrants) at month 12. Strongyloides seroprevalence fell from 21% (175/818) at baseline to 5% at month 6. For participants from the baseline cohort this reduction was sustained at month 12 (34/618, 6%), falling to 2% at month 18 after the second MDA. For new entrants to the cohort at month 12, seroprevalence reduced from 25% (75/297) to 7% at month 18. Strongyloides positive seroconversions for the baseline cohort six months after each MDA were 2.5% (4/157) at month 6 and 1% at month 18, whilst failure to serorevert remained unchanged at 18%. At 12 months, eosinophilia was identified in 59% of baseline seropositive participants and 89% of seropositive new entrants, compared with 47%baseline seronegative participants and 51% seronegative new entrants. Seropositivity was not correlated with haemoglobin or any self-reported clinical symptoms. Clinical symptoms ascertained on the day of treatment and 24–72 hrs after, did not identify any adverse events. Significance Two community ivermectin MDAs delivered 12 months apart by trained Aboriginal researchers in collaboration with non-Indigenous researchers resulted in a sustained and significant reduction in Strongyloides seroprevalence over 18 months. Similar reductions were seen in the baseline cohort and new entrants. We were invited by one community in East Arnhem Land to develop and deliver an ivermectin MDA to reduce the prevalence of Strongyloides and scabies. We demonstrated a sustained reduction in Strongyloides seroprevalence following the ivermectin MDA. Strongyloides is endemic in many Australian Aboriginal and Torres Strait Islander communities with seroprevalence ranging from 35–60%. Utilizing a before and after study design, we measured Strongyloides seroprevalence by ELISA through population census with sequential MDAs at baseline and month 12. Strongyloides seroprevalence reduced from 21% at baseline to 5% at month 6 after the first MDA. For the baseline cohort this reduction was sustained at month 12, falling to 2% at month 18 after the second MDA. For new entrants to the cohort at month 12, seroprevalence reduced from 25% to 7%.
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Affiliation(s)
- Therese M. Kearns
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- * E-mail:
| | - Bart J. Currie
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Allen C. Cheng
- School of Public Health and Preventive Medicine, Monash University and Infection Prevention and Healthcare Epidemiology Unit, Alfred Health Melbourne, Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jonathan R. Carapetis
- Telethon Kids Institute, University of Western Australia and Princess Margaret Hospital for Children, Perth, Australia
| | - Deborah C. Holt
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Wendy Page
- Miwatj Health Aboriginal Corporation, Nhulunbuy, Australia
| | - Jennifer Shield
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Roslyn Gundjirryirr
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | | | - Linda Ward
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Ross M. Andrews
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
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Aljayyoussi G, Tyrer HE, Ford L, Sjoberg H, Pionnier N, Waterhouse D, Davies J, Gamble J, Metuge H, Cook DAN, Steven A, Sharma R, Guimaraes AF, Clare RH, Cassidy A, Johnston KL, Myhill L, Hayward L, Wanji S, Turner JD, Taylor MJ, Ward SA. Short-Course, High-Dose Rifampicin Achieves Wolbachia Depletion Predictive of Curative Outcomes in Preclinical Models of Lymphatic Filariasis and Onchocerciasis. Sci Rep 2017; 7:210. [PMID: 28303006 PMCID: PMC5428297 DOI: 10.1038/s41598-017-00322-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/21/2017] [Indexed: 12/29/2022] Open
Abstract
Lymphatic filariasis (LF) and onchocerciasis are priority neglected tropical diseases targeted for elimination. The only safe drug treatment with substantial curative activity against the filarial nematodes responsible for LF (Brugia malayi, Wuchereria bancrofti) or onchocerciasis (Onchocerca volvulus) is doxycycline. The target of doxycycline is the essential endosymbiont, Wolbachia. Four to six weeks doxycycline therapy achieves >90% depletion of Wolbachia in worm tissues leading to blockade of embryogenesis, adult sterility and premature death 18-24 months post-treatment. Long treatment length and contraindications in children and pregnancy are obstacles to implementing doxycycline as a public health strategy. Here we determine, via preclinical infection models of Brugia malayi or Onchocerca ochengi that elevated exposures of orally-administered rifampicin can lead to Wolbachia depletions from filariae more rapidly than those achieved by doxycycline. Dose escalation of rifampicin achieves >90% Wolbachia depletion in time periods of 7 days in B. malayi and 14 days in O. ochengi. Using pharmacokinetic-pharmacodynamic modelling and mouse-human bridging analysis, we conclude that clinically relevant dose elevations of rifampicin, which have recently been determined as safe in humans, could be administered as short courses to filariasis target populations with potential to reduce anti-Wolbachia curative therapy times to between one and two weeks.
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Affiliation(s)
- Ghaith Aljayyoussi
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Hayley E Tyrer
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Louise Ford
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Hanna Sjoberg
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nicolas Pionnier
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - David Waterhouse
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jill Davies
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Joanne Gamble
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Haelly Metuge
- Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Darren A N Cook
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Andrew Steven
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Raman Sharma
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Ana F Guimaraes
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Rachel H Clare
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Andrew Cassidy
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Kelly L Johnston
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Laura Myhill
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Laura Hayward
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Samuel Wanji
- Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Joseph D Turner
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Mark J Taylor
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Stephen A Ward
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Antinori S, Parravicini C, Galimberti L, Tosoni A, Giunta P, Galli M, Corbellino M, Ridolfo AL. Is imported onchocerciasis a truly rare entity? Case report and review of the literature. Travel Med Infect Dis 2017; 16:11-17. [PMID: 28232074 DOI: 10.1016/j.tmaid.2017.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND Onchocerciasis is endemic in a number of tropical countries in Africa and South America, and it is occasionally diagnosed as an imported disease in non-endemic areas. METHODS We describe the case of an African migrant with long-lasting pruritus and a cutaneous nodule who was diagnosed with onchocerciasis after nodulectomy, and review the medical literature regarding imported cases of onchocerciasis in the period 1994-2014. RESULTS Twenty-nine cases of onchocerciasis diagnosed in migrants from endemic countries, and in expatriates and travellers from non-endemic areas were retrieved. They were predominantly males (73.3%), had a median age of 37 years (two were aged <15 years), and acquired the diseases in sub-Saharan Africa, most frequently in Cameroon (43.3%). Diagnosis of onchocercosis was proven in 73.3% of patients. The most frequent clinical manifestations in these and our own patient were pruritus (23/30, 76.7%), unilateral leg or forearm swelling (13/30, 43.3%) and rash (12/30, 40.0%), whereas only two (6.9%) complained of eye symptoms. Eosinophilia was observed in almost all of the patients (92.0%), with median counts of 2915/μL among migrants and 1960/μL among travellers/expatriates. Eighteen patients underwent a skin snip biopsy, which was positive in 10 cases (55.5%); in the other 13 patients the parasite was directly demonstrated by means of a skin or nodule biopsy (n = 5), nodulectomy (n = 5) or slit lamp examination (n = 3). Eighteen received ivermectin, alone, and seven ivermectin combined with diethylcarbamazine or doxycycline. Outcome details were available for only 14 patients, all of whom were asymptomatic after a median follow-up of 10 months (range 1-48). CONCLUSIONS Onchocerciasis is a neglected tropical disease whose subtle and non-specific features may lead to under-diagnosis or underreporting in non-endemic areas. Physicians should consider this tropical disease when caring for migrants and travellers/expatriates with pruritus, skin lesions and eosinophilia.
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Affiliation(s)
- Spinello Antinori
- Luigi Sacco Department of Biomedical and Clinical Sciences, University of Milano, Italy; III Division of Infectious Diseases, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy.
| | - Carlo Parravicini
- Pathology Unit, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
| | - Laura Galimberti
- III Division of Infectious Diseases, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
| | - Antonella Tosoni
- Pathology Unit, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
| | - Paolo Giunta
- Pathology Unit, Melegnano and Martesana ASST, Vizzolo Predabissi, Italy
| | - Massimo Galli
- Luigi Sacco Department of Biomedical and Clinical Sciences, University of Milano, Italy; III Division of Infectious Diseases, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
| | - Mario Corbellino
- III Division of Infectious Diseases, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
| | - Anna Lisa Ridolfo
- III Division of Infectious Diseases, Luigi Sacco Hospital, Fatebenefratelli Sacco ASST, Milano, Italy
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Onchocerciasis in the Democratic Republic of Congo: Survey of knowledge, attitude and perception in Bandundu province. J Infect Public Health 2017; 10:600-607. [PMID: 28215917 DOI: 10.1016/j.jiph.2017.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/16/2017] [Accepted: 01/28/2017] [Indexed: 11/23/2022] Open
Abstract
A community-directed treatment with ivermectin (CDTI) for fighting onchocerciasis was started in 2003 in the hyperendemic province of Bandundu, Democratic Republic of Congo (DRC); such initiative was supported by the African Programme for Onchocerciasis Control (APOC). As the APOC stopped at the end of 2015, there was an urgent need to assess the sustainability of an ivermectin treatment. A cross-sectional survey of knowledge, attitude and perception was conducted to determine the awareness level of local population regarding the disease. A multi-stage random sampling technique allowed the selection of 450 heads of households. Most respondents (96.9%) knew about onchocerciasis as a disease. The black-fly was viewed as the causing agent of onchocerciasis by 49.9% of respondents. The most commonly cited clinical manifestations were nodules (34.4%) and pruritus (31.1%), while blindness was the most frequently reported complication (90.7%). Approximately 55.1% of respondents had a good knowledge of onchocerciasis and CDTI. Overall, only 37% of participants had a favourable attitude and 46% a positive perception. Good knowledge was associated with school attendance (adjusted OR=1.9, 95%CI: 1.3-2.8, p=0.001), while education and continuation of treatment were related with good attitude (adjusted OR=9.7, 95%CI:4.8-19.5 and adjusted OR=19.8, 95%CI: 9.7-40.6, respectively, both with p<0.001). Good perception was associated with being at least 46 years old, non-Catholic and continuing the treatment (adjusted OR=3.2, 95%CI:1.2-9.1; adjusted OR=29.6, 95%CI:14.1-62.2 and adjusted OR=5.1, 95%CI:1.6-16.0 respectively, all with p<0.001). A good level of knowledge, attitude and perception is needed for a massive adherence of population to onchocerciasis control programmes. In the area of study (Moanza, DRC), good attitude and perception motivated the continuation of treatment in the population. In the future, different plans should focus on educational strategies to maintain a massive adherence and reduce onchocerciasis prevalence.
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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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Potential Value of Triple Drug Therapy with Ivermectin, Diethylcarbamazine, and Albendazole (IDA) to Accelerate Elimination of Lymphatic Filariasis and Onchocerciasis in Africa. PLoS Negl Trop Dis 2017; 11:e0005163. [PMID: 28056015 PMCID: PMC5215784 DOI: 10.1371/journal.pntd.0005163] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Meribo K, Kebede B, Feleke SM, Mengistu B, Mulugeta A, Sileshi M, Samuel A, Deribe K, Tadesse Z. Review of Ethiopian Onchocerciasis Elimination Programme. ETHIOPIAN MEDICAL JOURNAL 2017; 55:55-63. [PMID: 28878430 PMCID: PMC5582636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Onchocerciasis is a severe parasitic infection which causes disabling skin and subcutaneous tissue changes. The disease is endemic in many African countries including Ethiopia. In 2013, Ethiopia launched Onchocerciasis elimination program with the goal of attaining interruption of onchocerciasis transmission nationwide by 2020. The country has successfully scaled up interventions and achieved 100% geographic coverage in all known endemic districts. The main strategy for interrupting the disease is mass drug administration (MDA) delivered two times per year. The treatment coverage for the last five years has been maintained at more than 80%. Despite many years of ivermectin MDA the transmission of onchocerciasis in many districts remained unabated. To achieve the 2020 goal, sustained high geographic and therapeutic coverage is required which is validated by coverage surveys. The programme should aim to improve the knowledge and attitude of the community towards the programme in order to improve drug compliance. The partnership between the relevant stakeholders should be strengthened to facilitate open discussions regarding the programme implementation and any challenges that may arise in the control and elimination of the disease. It is also important to consider intensified vector control.
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Affiliation(s)
- Kadu Meribo
- Federal Ministry of Health, Addis Ababa Ethiopia
| | | | | | | | - Abate Mulugeta
- World Health Organization, Ethiopia Country Office, Addis Ababa
| | | | - Abdi Samuel
- Wollega University College of Medical and Health Sciences, Department of Medical Laboratory Sciences, Nekemte, Ethiopia
| | - Kebede Deribe
- Federal Ministry of Health, Addis Ababa Ethiopia
- RTI International, Addis Ababa, Ethiopia
- Wellcome Trust Brighton & Sussex Centre for Global Health Research, Brighton & Sussex Medical School, Falmer, Brighton, UK
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Wolbachia endosymbionts induce neutrophil extracellular trap formation in human onchocerciasis. Sci Rep 2016; 6:35559. [PMID: 27752109 PMCID: PMC5067710 DOI: 10.1038/srep35559] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 10/03/2016] [Indexed: 12/12/2022] Open
Abstract
The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline. Whole Wolbachia or microspheres coated with a synthetic Wolbachia lipopeptide (WoLP) of the major nematode Wolbachia TLR2/6 ligand, peptidoglycan associated lipoprotein, induced NETosis in human neutrophils in vitro. TLR6 dependency of Wolbachia and WoLP NETosis was demonstrated using purified neutrophils from TLR6 deficient mice. Thus, we demonstrate for the first time that NETosis occurs during natural human helminth infection and demonstrate a mechanism of NETosis induction via Wolbachia endobacteria and direct ligation of Wolbachia lipoprotein by neutrophil TLR2/6.
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Ocular parasitoses: A comprehensive review. Surv Ophthalmol 2016; 62:161-189. [PMID: 27720858 DOI: 10.1016/j.survophthal.2016.09.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 09/27/2016] [Accepted: 09/29/2016] [Indexed: 12/14/2022]
Abstract
Parasitic infections of the eyes are a major cause of ocular diseases across the globe. The causative agents range from simple organisms such as unicellular protozoans to complex metazoan helminths. The disease spectrum varies depending on the geographic location, prevailing hygiene, living and eating habits of the inhabitants, and the type of animals that surround them. They cause enormous ocular morbidity and mortality not because they are untreatable, but largely due to late or misdiagnosis, often from unfamiliarity with the diseases produced. We provide an up-to-date comprehensive overview of the ophthalmic parasitoses. Each section describes the causative agent, mode of transmission, geographic distribution, ocular pathologies, and their management for common parasites with brief mention of the ones that are rare.
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Moya L, Herrador Z, Ta-Tang TH, Rubio JM, Perteguer MJ, Hernandez-González A, García B, Nguema R, Nguema J, Ncogo P, Garate T, Benito A, Sima A, Aparicio P. Evidence for Suppression of Onchocerciasis Transmission in Bioko Island, Equatorial Guinea. PLoS Negl Trop Dis 2016; 10:e0004829. [PMID: 27448085 PMCID: PMC4957785 DOI: 10.1371/journal.pntd.0004829] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 06/16/2016] [Indexed: 11/30/2022] Open
Abstract
Onchocerciasis or "river blindness" is a chronic parasitic neglected tropical disease which is endemic both in mainland and insular Equatorial Guinea. We aim to estimate the current epidemiological situation of onchocerciasis in Bioko Island after vector elimination in 2005 and more than sixteen years of Community Directed Treatment with Ivermectin (CDTI) by using molecular and serological approaches for onchocerciasis diagnosis. A community-based cross-sectional study was carried out in Bioko Island from mid-January to mid-February 2014. A total of 544 study participants were recruited. A complete dermatological examination was performed and three skin snips were performed in every participant for parasitological and molecular assessments. Blood spots were also taken for determination of Ov16 IgG4 antibodies trough an “in-house” ELISA assay. Overall, we found 15 out of 522 individuals suffering any onchocerciasis specific cutaneous lesions and 16 out of 528 (3.0%) with onchocercal nodules in the skin. Nodules were significantly associated with age, being more common in subjects older than 10 years than in younger people (3.9% vs. 0%, p = 0.029). Regarding the onchocerciasis laboratory assessment, no positive parasitological test for microfilaria detection was found in the skin snips. The calculated seroprevalence through IgG4 serology was 7.9%. No children less than 10 years old were found to be positive for this test. Only one case was positive for Onchocerca volvulus (O. volvulus) after skin PCR. The present study points out that the on-going mass ivermectin treatment has been effective in reducing the prevalence of onchocerciasis and corroborates the interruption of transmission in Bioko Island. To our knowledge, this is the first time that accurate information through molecular and serological techniques is generated to estimate the onchocerciasis prevalence in this zone. Sustained support from the national program and appropriate communication and health education strategies to reinforce participation in CDTI activities are essential to ensure progress towards onchocerciasis elimination in the country. Onchocerciasis or “river blindness” is a chronic parasitic disease which is mainly found in Sub-Saharan Africa. Onchocerciasis is endemic in both mainland and insular Equatorial Guinea. Huge achievements have been made on onchocerciasis control in Bioko Island in the last years, and the country is moving fast towards elimination. In the new elimination context, monitoring and evaluation activities with more sensitive diagnostic tools become especially necessary in order to confirm that transmission has been interrupted. Previous data on the epidemiological situation of onchocerciasis in Bioko Island are mainly based on microfilaria (MF) skin snip assessments. We aim to create evidence towards the fact that onchocerciasis transmission might have been achieved in Bioko Island after more than sixteen years of onchocerciasis control activities by using molecular and serological technics for onchocerciasis diagnosis.
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Affiliation(s)
- Laura Moya
- Jimenez Diaz Foundation, Madrid, Spain
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- * E-mail:
| | - Zaida Herrador
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Thuy Huong Ta-Tang
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Jose Miguel Rubio
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Maria Jesús Perteguer
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Ana Hernandez-González
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Belén García
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
| | - Rufino Nguema
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Justino Nguema
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Policarpo Ncogo
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
| | - Teresa Garate
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Agustín Benito
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Anacleto Sima
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Pilar Aparicio
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
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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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Lupi O, Downing C, Lee M, Pino L, Bravo F, Giglio P, Sethi A, Klaus S, Sangueza OP, Fuller C, Mendoza N, Ladizinski B, Woc-Colburn L, Tyring SK. Mucocutaneous manifestations of helminth infections: Nematodes. J Am Acad Dermatol 2016; 73:929-44; quiz 945-6. [PMID: 26568337 DOI: 10.1016/j.jaad.2014.11.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 11/30/2022]
Abstract
In the 21st century, despite increased globalization through international travel for business, medical volunteerism, pleasure, and immigration/refugees into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on the cutaneous manifestations of helminth infections and is divided into 2 parts: part I focuses on nematode infections, and part II focuses on trematode and cestode infections. This review highlights the clinical manifestations, transmission, diagnosis, and treatment of helminth infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.
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Affiliation(s)
- Omar Lupi
- Federal University of the State of Rio de Janeiro and Policlinica Geral do Rio de Janeiro, Rio de Janerio, Brazil
| | - Christopher Downing
- Department of Dermatology, University of Texas Health Science Center, Houston, Texas.
| | - Michael Lee
- Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Livia Pino
- Federal University of the State of Rio de Janeiro and Policlinica Geral do Rio de Janeiro, Rio de Janerio, Brazil
| | - Francisco Bravo
- Instituto de Medicina Tropical Alexander von Humboldt, Lima, Peru; Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Aisha Sethi
- Section of Infectious Diseases and Global Health, Department of Dermatology, University of Chicago, Chicago, Illinois
| | - Sidney Klaus
- Department of Dermatology, Dartmouth School of Medicine, Hanover, New Hampshire
| | - Omar P Sangueza
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Claire Fuller
- International Foundation for Dermatology and Consultant, Chelsea and Westminster Hospital, London, United Kingdom
| | - Natalia Mendoza
- Department of Dermatology, University of Texas Health Science Center, Houston, Texas
| | - Barry Ladizinski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Laila Woc-Colburn
- National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas
| | - Stephen K Tyring
- Center for Clinical Studies, Houston, Texas; Department of Dermatology, University of Texas Health Science Center, Houston, Texas
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