In 1998, circulation of the Rift Valley Fever (RVF) virus was revealed in Diawara by detection of IgM antibodies in sheep and isolation of the virus from mosquitoes caught outside a village. A seroprevalence study was carried out. Finger-prick blood samples, individual and collective details were obtained. One thousand five hundred twenty people (6 months-83 years) were included. Overall prevalence in this group was approximately 5.2%. The prevalence in infants (6 months-2 years) was 8.5%. Age, gender, contact with a pond, presence of sheep, and abortion among sheep, and individual or collective travel history were not statistically associated with prevalence. Prevalence increased significantly when the distance to a small ravine, located in the middle of the village, decreased. The results suggest a low, recent, not endemic circulation of the virus. Culex quinquefasciatus was captured near the ravine. This mosquito, similar to Culex pipiens, can play a similar role in human-to-human transmission of the RVF virus. tive sheep and cattle was again observed along the Senegal River (Fontenille et al, 1998). In September and October 1998, RVF virus was isolated in Mauritania (Diallo et al, 2000). In November 1998, an entomological and veterinary study was carried out in the valley of the Senegal River to detect specific IgM antibodies in sheep, in the villages of Thillé Boubacar, Diawara and Kidira, isolate the virus in mosquitoes caught around a pond located in the vicinity of Diawara (Diallo et al, 2000). This latter village is located in Bakel’s district, near the border of Mauritania and Mali.

A cross-sectional survey was carried out on the human population of Diawara to estimate the prevalence of RVF virus-specific immunoglobulin (Ig) G antibody in the population, to investigate a recent or previous circulation of the RVF virus and to identify the risk factors for exposure to the virus.