RESUMEN
To estimate the prevalence and distribution of bluetongue virus antibody in sheep and goats in 25 townships of Khorasan Razavi. Bluetongue is an infectious, non-contagious, arthropod born viral disease of ruminants and has been reported from most of the tropical and subtropical regions of the world. Methods: A total number of 1 034 serum samples from sheep and goats were collected and transmitted to Serological Laboratory of Veterinary Council of Khorasan Razavi. Serums were screened for the presence of group-specific bluetongue virus antibody using competitive Enzyme Linked Immuno Sorbent Assay (c-ELISA). Results: The seropositivity of sheep and goats for bluetongue was found to be 89.2%. The highest prevalence rate was seen in Taybad, Khalil-abad and Torbat-jam (100%) and the least prevalence rate was seen in Jovein (55%). Conclusions: The results showed that the majority of animals in the north-east of Iran are infected with bluetongue virus. High correlation between abortion history and seroposivity emphasize the economical importance of bluetongue virus in the sheep herds of the region.