1Division of Virology, DRDE, Jhansi Road, Gwalior- 474 002 (M.P.).
2Division of Virology, Indian Veterinary Research Institute, Mukteswar Campus - 263 138 (Uttaranchal).
*Corresponding Author; CADRAD, Indian Veterinary Research Institute (IVRI), Izatnagar - 243 122, Bareilly (U.P.)
Blue tongue is an economically devastating arboviral infection of sheep, goat, cattle and wild ruminants. Outbreaks of this disease have been increasingly reported from different parts of India. Twenty one, out of possible 24 serotypes of Bluetongue virus (BTV) have been reported in our country. Classification of Bluetongue into OIE category ‘A’ disease puts trade barrier, inflicting staggering losses to the national economy. L2 gene of BTV is of prime importance among all the 10 genes of the BTV, since it codes for the major serotype specific protein VP2. The genetic nature of L2 gene of Indian BTV isolates is poorly studied. The circulation of BTV isolates in India is very poorly studied. In this study, the sequence information of two different regions of L2 gene of an Indian BTV-23 isolate was deciphered for the first time and the suitability of each region was evaluated for molecular phylogenetic analysis. The sequence analysis revealed the conservation of sequences within a serotype and variation among serotypes. The Indian BTV-23 isolate was found to be phylogenetically closely related to Australian BTV-23 isolates, irrespective of the genomic region compared for analysis. Both the dendrograms revealed similar branching patterns, confirming that both regions are equally suitable for phylogenetic analysis. The sequence information and the phylogenetic analysis carried out in this study provides a rapid alternative approach for characterization of circulating strains and for future molecular epidemiological investigations around the world.
