Not AvailableBovine leukaemia virus (BLV) causes enzootic leucosis in cattle and is prevalentworldwide. Although recent studies have shown that BLV strains can be classifiedinto 10 distinct genotypes, no information is available regarding the BLV genotypeprevalent in cattle in India. To determine the genetic variability in BLV, in this study,118 adult dairy cows from three states of India were screened for BLV infection byenvgp51‐specific ELISA and nested PCR. Of the 33 cows found positive by bothPCR and ELISA, 10 selected BLV strains were subjected to molecular characteriza-tion. Phylogenetic analyses of partial and full‐lengthenvgp51 gene sequences ofIndian BLV strains and other geographical diverse BLV strains representing all the10 genotypes revealed that Indian strains belonged to BLV genotype 6. AlthoughIndian strains showed close genetic proximity with the strains circulating in SouthAmerica, they were classified into a new subgenotype within genotype 6. Alignmentof deduced amino acid sequences in gp51 demonstrated substitutions mainly inconformational epitope G, neutralizing domain 2 and linear epitope D, with a novelmutation (threonine to alanine at residue 252) found in D‐epitope of all the IndianBLV strains. Although serological evidence of BLV infection in India has beenreported earlier, this study on molecular characterization of BLV strains establishedthe existence of BLV genotype 6 in India. Additionally, the results of this studyhighlight the importance of genetic analysis of geographically diverse BLV strains tounderstand BLV global genetic diversity and further studies are required to deter-mine BLV genetic diversity and extent of BLV infection in cattle in India.Not Availabl
