Kher, H. N.Chandel, Bharat Singh2018-07-022018-07-021996http://krishikosh.egranth.ac.in/handle/1/5810056275Bluetongue (BT) is an infectious, non contagious disease of domestic and wild ruminants. Bluetongue virus ( BTV ) causes severe disease in sheep, which i s transmitted by insect vectors (Culicoides spp.) . The ability of BTVs to inflict pathological changes in susceptible sheep depends on the virulence of a particular viral isolate , susceptibility of the host and a number of environmental factors related to climatic conditions. The present study was aimed at the seroepidemiology, prevalence of BTV serotypes in sheep, isolation, propagation and identification of local isolates and pathogenicity of BTV in natural and experimental cases of sheep. This study also covered the seroprevalence of epizootic haemorrhagic disease virus (EHDV) in cattle and buffaloes as it is related to orbivirus group. A seroepidentiological survey of BTV precipitating antibodies was carried out by agar gel immunodiffusicm ( AGID ) test in different species of livestock in Gujarat. Out of 1623 sera tested, 407 (25.07%) were found to be positive for BTV antibodies.enVETERINARY MICROBIOLOGYA STUDYThesis