title: Environmental risk factors of West Nile virus infection of horses in the Senegal River basin.
abstract: In 2005, a serological study was carried out on horses in five ecologically contrasted zones of the Senegal River basin (Senegal) to assess West Nile virus (WNV) transmission and investigate underlying environmental risk factors. In each study zone, horses were randomly selected and blood samples taken. A land-cover map of the five study areas was built using two satellite ETM+ images. Blood samples were screened by ELISA for anti-WNV IgM and IgG and positive samples were confirmed by seroneutralization. Environmental data were analysed using a principal components analysis. The overall IgG seroprevalence rate was 85% (n=367; 95% CI 0.81-0.89). The proximity to sea water, flooded banks and salted mudflats were identified as protective factors. These environmental components are unfavourable to the presence of Culex mosquitoes suggesting that in Senegal, the distribution of the vector species is more limiting for WNV transmission than for the hosts' distribution.
authors.affiliation: CIRAD, UR Animal et Gestion Intégrée des Risques (AGIRs), Montpellier, France. chevalier@cirad.fr
authors.forename: V
authors.initials: V
authors.lastname: Chevalier
authors.forename: A
authors.initials: A
authors.lastname: Dupressoir
authors.forename: A
authors.initials: A
authors.lastname: Tran
authors.forename: O M
authors.initials: OM
authors.lastname: Diop
authors.forename: C
authors.initials: C
authors.lastname: Gottland
authors.forename: M
authors.initials: M
authors.lastname: Diallo
authors.forename: E
authors.initials: E
authors.lastname: Etter
authors.forename: M
authors.initials: M
authors.lastname: Ndiaye
authors.forename: V
authors.initials: V
authors.lastname: Grosbois
authors.forename: M
authors.initials: M
authors.lastname: Dia
authors.forename: N
authors.initials: N
authors.lastname: Gaidet
authors.forename: A A
authors.initials: AA
authors.lastname: Sall
authors.forename: V
authors.initials: V
authors.lastname: Soti
authors.forename: M
authors.initials: M
authors.lastname: Niang
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D003465:Culex / Q000502:physiology / Q000821:virology; D003710:Demography; D017753:Ecosystem; D004777:Environment; D006734:Horse Diseases / Q000453:epidemiology* / Q000821:virology; D006736:Horses; D007074:Immunoglobulin G / Q000097:blood; D007303:Insect Vectors / Q000502:physiology / Q000821:virology; D012307:Risk Factors; D045483:Rivers; D012675:Senegal / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D014901:West Nile Fever / Q000453:epidemiology / Q000662:veterinary*; D014902:West Nile virus / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G