Vaccination in the control of bluetongue in endemic regions: the South African experience.

The eradication of bluetongue virus (BTV) from endemic regions of Africa is virtually impossible due to the role played by the widely distributed Culicoides spp. of midge vectors and the ubiquitous distribution of reservoir species. In endemic areas attempts can only be made to limit the occurrence of bluetongue (BT) disease and its economic impact through vaccination. Despite several potential problems (teratogenicity, risk of reassortment and reversion to virulence of the attenuated viral strains), epidemiological and recent molecular data support the fact that the live attenuated vaccine that has been used for decades in enzootic regions, provides a safe and efficacious means to control the disease in regions of southern Africa, as well as other areas of the world.