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Assaré RK, N’Tamon RN, Bellai LG, Koffi JA, Mathieu TBI, Ouattara M, Hürlimann E, Coulibaly JT, Diabaté S, N’Goran EK, Utzinger J. Characteristics of persistent hotspots of Schistosoma mansoni in western Côte d'Ivoire. Parasit Vectors 2020; 13:337. [PMID: 32616074 PMCID: PMC7333430 DOI: 10.1186/s13071-020-04188-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 06/13/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Preventive chemotherapy with praziquantel is the cornerstone of schistosomiasis control. However, in some social-ecological settings, the prevalence and/or intensity of Schistosoma infection does not lower meaningfully despite multiple rounds of preventive chemotherapy, a phenomenon termed persistent hotspot (PHS). We assessed the characteristics of PHS in a Schistosoma mansoni-endemic area of Côte d'Ivoire. METHODS In October 2016, a cross-sectional survey was conducted in 14 schools in the western part of Côte d'Ivoire, one year after multiple rounds of preventive chemotherapy. In each school, 50 children aged 9-12 years provided two stool samples and one urine sample. Stool samples were subjected to triplicate Kato-Katz thick smears for S. mansoni diagnosis. Urine samples were examined by a filtration method for S. haematobium eggs. PHS was defined as failure to achieve a reduction in the prevalence of S. mansoni infection of at least 35% and/or a reduction of infection intensity of at least 50%. Six schools underwent more detailed investigations, including a questionnaire survey for demographic characteristics and a malacological survey. RESULTS In the six schools subjected to detailed investigations, the overall prevalence of S. mansoni and S. haematobium was 9.5% and 2.6%, respectively. Four schools were classified as PHS. The S. mansoni prevalence in the four PHS was 10.9% compared to 6.6% in the remaining two schools. The S. mansoni infection intensity, expressed as arithmetic mean eggs per gram of stool (EPG) among infected children, was 123.8 EPG in PHS and 18.7 EPG in the other two schools. Children bathing in open freshwater bodies were at higher odds of S. mansoni infection (odds ratio: 4.5, 95% confidence interval: 1.6-12.6). A total of 76 human-water contact sites (53 in PHS and 23 in the other schools) were examined and 688 snails were collected, including potential intermediate host snails of Schistosoma (Biomphalaria pfeifferi, Bulinus forskalii, Bu. globosus and Bu. truncatus). CONCLUSION Children in PHS schools bathed more frequently in open freshwater bodies, and hence, they are more exposed to Schistosoma transmission. Our findings call for an integrated control approach, complementing preventive chemotherapy with other interventions, particularly in PHS settings.
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Affiliation(s)
- Rufin K. Assaré
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland
- University of Basel, CH-4003, Basel, Switzerland
| | - Roméo N. N’Tamon
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
| | - Louise G. Bellai
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland
- University of Basel, CH-4003, Basel, Switzerland
| | - Judicaelle A. Koffi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
- Unité de Formation et de Recherche Science de l’Homme et de la Société, Université Félix Houphouët-Boigny, 08 BP 865, Abidjan 08, Côte d’Ivoire
| | - Tra-Bi I. Mathieu
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
| | - Mamadou Ouattara
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
| | - Eveline Hürlimann
- Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland
- University of Basel, CH-4003, Basel, Switzerland
| | - Jean T. Coulibaly
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland
- University of Basel, CH-4003, Basel, Switzerland
| | - Salia Diabaté
- Centre d’Entomologie Médicale et Vétérinaire, 27 BP 529, Abidjan 27, Côte d’Ivoire
| | - Eliézer K. N’Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303, Abidjan 01, Côte d’Ivoire
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland
- University of Basel, CH-4003, Basel, Switzerland
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