Bluetongue disease

Bluetongue (BT) is a noncontagious OIE-listed disease of domestic and wild ruminants caused by a virus (Bluetongue virus—BTV) of the Orbivirus genus within the family Reoviridae and transmitted by biting midges of the genus Culicoides. BT is a considerable socioeconomic concern and of major importance for the international trade of animals and animal products. In the past, BT endemic areas were considered those between latitudes 40 °N and 35 °S; however, BT has spread far beyond this traditional range. BTV has multiple serotypes and these serotypes exist in a complex network of serological cross-relationships, varying from partial to no protection between heterologous strains. This chapter summarizes several aspects of BT and BTV with particular emphasis for BTV epidemiology in Sahelian Africa.