Genetic diversity of BLV, common in the territory of the Kochenevsky district of the Novosibirsk region
This study evaluated bovine leukemia virus (BLV) prevalence in Kochenevsky district, Novosibirsk region,Russia. BLV prevalence data in farmsteads of private farmers and large livestock farms were obtained; phylogenetic analysis was conducted to define BLV genotypes in the study region. PCR analysis was used to detect BLV proviral cDNA; focal virus spread was identified. The BL V prevalence among the cattle of the private farmsteads ranged from 0% to 79% across the study areas. Among the livestocks of the Kochenevsky district, 7 2% of samples were positive for BLV. The BVL 1000-bp genome fragment coding the env gene region was obtained for 191 samples. The following phylogenetic analysis was performed and 162 sequences were classified as genotype 4 and the remaining 29 sequences were classified as genotype 7. BLV 7 genotype was identified among Proskudnoe private farmsteads only, while BLV genotype 4 was widespread across the region. Both BLV genotype 7 (n= 17) and 4 (n=126) were detected in the dairy farm. Phylogenetic analysis revealed distinct clusters (with a bootstrap support value >75) of BLV sequences most likely indicating to the several transmission routes of the infection in the Kochenevsky district. The study results can be used to replenish fundamental knowledge about the BLV evolution and development of novel BL V prevention and elimination approaches.