Abstract Bluetongue disease (BT) is a vector borne infectious but noncontagious disease of wild and domestic ruminants. The BTV isolate (7bp) of sheep origin was inoculated to 9-11 day old chicken embryo followed by BHK-21 cell culture. Upon appearance of 75% cytopathic effect in cell culture viral nucleic acid was extracted. The viral nucleic acid showed BTV specific migration pattern of 3:3:3:1 in RNA-PAGE. The group specific ns1 gene RT-PCR confirmed the sample as BTV. The vp2 gene based serotype specific RT-PCR revealed the isolate as BTV16. The nucleic acid sequence of vp2 gene PCR products showed a high degree of identity (>99.0%) with other BTV16 isolates from different regions of India. It also showed maximum nucleotide identity of 99.7- 96.4% with several other eastern BTV16 viruses from India, Israel, Japan, Cyprus, Greece etc. Sequence identity study also revealed that 7bp isolate only showed 75.5% identity with western isolate of BTV16 from Nigeria. The phylogenetic study also showed a close relation between isolate in study and BTV16 isolates from India Japan, Israel and Greece which form a separate eastern cluster. Thus, molecular study showed that the isolate in study is of eastern origin and closer to BTV16 isolates from India, Greece, Japan, and Israel.
Key words: Bluetongue Virus 16; Topotype; vp2 Gene; RT-PCR.