West Nile transmission was shown to be endemic in the Ferlo area, a sahelian part of Senegal. A serological study was carried out on horses in the Senegal river basin to assess the epidemiological status of this area for WN transmission and try to identify environmental risk factors of this transmission. Two satellite ETM+ images from the dry and wet seasons were used to provide a land-cover map of the study area. Using generalized linear mixed model and a component analysis strategy, the results showed that (i) WN virus is endemic in this region; (ii) the transmission differed with landscape despite a global high transmission level. This first landscape approach in an endemic area may provide a methodology to identify risk areas in non-endemic areas and target the surveillance.