Isolation and Complete Genome Sequencing of Bluetongue Virus Serotype 12 from India

Bluetongue virus (BTV) causes disease mainly in sheep, but can be transmitted via other domestic and wild ruminants, resulting in pecuniary burden and trade restrictions. Segmented genome with the possibility of reassortment, existence of 26 serotypes, geographical restriction in the distribution of many of the serotypes, use of live attenuated vaccines and the lack of complete sequences of viruses isolated from several parts of the globe have complicated our understanding of the origin, movement and distribution of BTV. Recent efforts in genome sequencing of several strains have helped in better comprehending BTV epidemiology. In an effort to contribute to the genetic epidemiology of BTV in India, we report the isolation and complete genome sequencing of a BTV serotype 12 virus (designated NMO1). This is the first BTV-12 isolated from India and the second BTV-12 to be sequenced worldwide. The analysis of sequences of this virus suggests that NMO1 derived its segments from viruses belonging to western topotype viruses, as well as those from South-East Asia and India. The results have implications for understanding the origin, emergence/re-emergence and movement of BTV as well as for the development of vaccines and diagnostics based on robust epidemiological data.