Detection and Characterization Based on S7 and S10 Gene Segments of Bluetongue Virus Isolates from Andhra Pradesh, India

The surveillance of Bluetongue disease (BT) during 2009-2010 outbreaks in the districts of Chittoor, Nellore, Nizamabad, Krishna, Guntur, Kadapa and Ongole, Andhra Pradesh, India revealed the occurrence of high morbidity, mortality, abortions, stillbirths, loss of fleece, reduced meat production in affected sheep leading to the vast economic loss to the poor section of Indian farming community. During 2009 and 2010 a total of 130 BT suspected clinical (blood) samples were collected from infected sheep. Analysis of the clinical samples in RT-PCR confirmed association of Bluetongue Virus (BTV) with the disease. RT-PCR was optimized for the amplification of S7 (VP7) and S10 (NS3) genes of field isolates with reference to BTV-2-Tirupati isolate. The amplicons were cloned, sequenced and submitted to Genbank. Phylogenetic characterization of these virus isolates based on S7 and S10 genes with all other reported isolates concluded that the present study isolates could be BTV-2 circulating in Andhra Pradesh, India.