RESUMEN
INTRODUCTION: first infected cases caused by West Nile virus were reported in Cuba in 2004. OBJECTIVE: to monitor and learn about the prevalence of the West Nile virus in those areas with confirmed cases. METHODS: the study was conducted in Jatibonico municipality and in the city of sancti Spiritus. A total number of 14 persons, 8 horses and 41 birds were researched to detect antibodies to flavivirus and specific antibodies to West Nile virus. RESULTS: the presence of specific antibodies to West Nile virus was confirmed in 4 samples of sera from birds and in 4 from horses. One person was confirmed as one case of asymptomatic West Nile virus infection. CONCLUSIONS: the presence of specific antibodies to West Nile virus in birds, horses and persons residing in areas where there are confirmed cases showed that a local amplification cycle had been established in Cuba before this study.