Bluetongue
Bluetongue virus (BTV) continues to surprise the scientific community and requires constant adaptation of previous assumed knowledge. This chapter deals with various aspects of the biology and potential control of BTV infection with particular reference to evolving trends in vaccines and vaccination strategies that might be used to control this economically important disease. Bluetongue vaccines are divided into nonreplicating and replicating vaccines. Inactivated, whole-virus and live attenuated virus vaccines are the only nonreplicating and replicating BT vaccines available in the market. Following infection with BTV, antibodies against all structural and nonstructural viral proteins can be detected in the serum of ruminants. Neutralizing antibodies are the immune correlate believed to protect previously infected animals against reinfection with a BTV strain of the homologous serotype. The basis of protective immunity of livestock to BTV infection is increasingly defined, including the protective immunogens of BTV.