Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa
Abstract Background Effective control of schistosomiasis remains a challenging problem for endemic areas of the world. Given knowledge of the biology of transmission and past experience with mass drug administration (MDA) programs, it is important to critically evaluate the likelihood that MDA progr...
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| Format: | Article |
| Language: | English |
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BMC
2015-10-01
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| Series: | Parasites & Vectors |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s13071-015-1144-3 |
| _version_ | 1827933709281525760 |
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| author | David Gurarie Nara Yoon Emily Li Martial Ndeffo-Mbah David Durham Anna E. Phillips H. Osvaldo Aurelio Josefo Ferro Alison P. Galvani Charles H. King |
| author_facet | David Gurarie Nara Yoon Emily Li Martial Ndeffo-Mbah David Durham Anna E. Phillips H. Osvaldo Aurelio Josefo Ferro Alison P. Galvani Charles H. King |
| author_sort | David Gurarie |
| collection | DOAJ |
| description | Abstract Background Effective control of schistosomiasis remains a challenging problem for endemic areas of the world. Given knowledge of the biology of transmission and past experience with mass drug administration (MDA) programs, it is important to critically evaluate the likelihood that MDA programs will achieve substantial reductions in Schistosoma prevalence. In implementing the World Health Organization Roadmap for Neglected Tropical Diseases it would useful for policymaking to model projections of the status of Schistosoma control in MDA-treated areas in the next 5–10 years. Methods Calibrated mathematical models were used to project the effects of different frequency and coverage of MDA for schistosomiasis haematobia control in present-day endemic communities, taking into account uncertainties of parasite biology and input data. The modeling approach in this analysis was the Stratified Worm Burden model developed in our earlier works, calibrated using data from longitudinal S. haematobium control trials in Kenya. Results Model-based simulations of MDA control in typical low-risk and higher-risk communities indicated that infection prevalence can be substantially reduced within 10 years only when there is a high degree of community participation (>70 %) with at least annual MDA. Significant risk for re-emergence of infection remains if MDA is suspended. Conclusions In a stable (stationary) ecosystem, Schistosoma reproduction and transmission are sufficiently robust that the process of human infection continues, even under pressure from aggressive MDA. MDA alone is unlikely to interrupt transmission, and once mass treatment is suspended, the prevalence of human infection is likely to rebound to pre-control levels over a period of 25–30 years. MDA success in achieving very low levels of infection prevalence is highly dependent on treatment coverage and frequency within the local human population, and requires that both adults and children be included in drug delivery coverage. Ultimately, supplemental snail control and significant improvements in sanitation will be required to achieve full control of schistosomiasis by elimination of ongoing Schistosoma transmission. |
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| format | Article |
| id | doaj.art-8cc9ddd9e0294e9da37933a086df522b |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-03-13T07:28:33Z |
| publishDate | 2015-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Parasites & Vectors |
| spelling | doaj.art-8cc9ddd9e0294e9da37933a086df522b2023-06-04T11:13:40ZengBMCParasites & Vectors1756-33052015-10-018111410.1186/s13071-015-1144-3Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in AfricaDavid Gurarie0Nara Yoon1Emily Li2Martial Ndeffo-Mbah3David Durham4Anna E. Phillips5H. Osvaldo Aurelio6Josefo Ferro7Alison P. Galvani8Charles H. King9Department of Mathematics, Case Western Reserve UniversityDepartment of Mathematics, Case Western Reserve UniversityCenter for Global Health and Diseases, School of Medicine, Case Western Reserve UniversityDepartment of Epidemiology, Yale School of Public HealthDepartment of Epidemiology, Yale School of Public HealthSchistosomiasis Control Initiative, Imperial CollegeSchistosomiasis Control Initiative, Imperial CollegeUniversidade Catholica de MoçambiqueDepartment of Epidemiology, Yale School of Public HealthCenter for Global Health and Diseases, School of Medicine, Case Western Reserve UniversityAbstract Background Effective control of schistosomiasis remains a challenging problem for endemic areas of the world. Given knowledge of the biology of transmission and past experience with mass drug administration (MDA) programs, it is important to critically evaluate the likelihood that MDA programs will achieve substantial reductions in Schistosoma prevalence. In implementing the World Health Organization Roadmap for Neglected Tropical Diseases it would useful for policymaking to model projections of the status of Schistosoma control in MDA-treated areas in the next 5–10 years. Methods Calibrated mathematical models were used to project the effects of different frequency and coverage of MDA for schistosomiasis haematobia control in present-day endemic communities, taking into account uncertainties of parasite biology and input data. The modeling approach in this analysis was the Stratified Worm Burden model developed in our earlier works, calibrated using data from longitudinal S. haematobium control trials in Kenya. Results Model-based simulations of MDA control in typical low-risk and higher-risk communities indicated that infection prevalence can be substantially reduced within 10 years only when there is a high degree of community participation (>70 %) with at least annual MDA. Significant risk for re-emergence of infection remains if MDA is suspended. Conclusions In a stable (stationary) ecosystem, Schistosoma reproduction and transmission are sufficiently robust that the process of human infection continues, even under pressure from aggressive MDA. MDA alone is unlikely to interrupt transmission, and once mass treatment is suspended, the prevalence of human infection is likely to rebound to pre-control levels over a period of 25–30 years. MDA success in achieving very low levels of infection prevalence is highly dependent on treatment coverage and frequency within the local human population, and requires that both adults and children be included in drug delivery coverage. Ultimately, supplemental snail control and significant improvements in sanitation will be required to achieve full control of schistosomiasis by elimination of ongoing Schistosoma transmission.https://doi.org/10.1186/s13071-015-1144-3Mathematical modelsTheoretical/parasitologySchistosomiasis/prevention and controlDrug therapy/organization and administrationDisease transmissionInfectious disease |
| spellingShingle | David Gurarie Nara Yoon Emily Li Martial Ndeffo-Mbah David Durham Anna E. Phillips H. Osvaldo Aurelio Josefo Ferro Alison P. Galvani Charles H. King Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa Parasites & Vectors Mathematical models Theoretical/parasitology Schistosomiasis/prevention and control Drug therapy/organization and administration Disease transmission Infectious disease |
| title | Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa |
| title_full | Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa |
| title_fullStr | Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa |
| title_full_unstemmed | Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa |
| title_short | Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa |
| title_sort | modelling control of schistosoma haematobium infection predictions of the long term impact of mass drug administration in africa |
| topic | Mathematical models Theoretical/parasitology Schistosomiasis/prevention and control Drug therapy/organization and administration Disease transmission Infectious disease |
| url | https://doi.org/10.1186/s13071-015-1144-3 |
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