[1] Ctr Rech Entomol Cotonou CREC, 06 BP 2604, Cotonou, Benin
[2] Univ Abomey Calavi, Fac Sci & Tech, Dept Biochem & Cellular Biol, Lab Biol & Mol Typing Microbiol, 05 BP 1604, Cotonou, Benin
[3] Univ Natl Agr Porto Novo, Ecole Gest & Exploitat Syst Elevage, 01 BP 55, Porto Novo, Benin
[4] Univ Parakou, Fac Agron, BP 123, Parakou, Benin
[5] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, Dis Control Dept, Keppel St, London WC1E 7HT, England