A New Approach to the Diagnosis of Enzootic Leukosis by Genetic Markers of Bovine Leukemia Virus

In this paper, we consider the gp51 and p24 genes of the bovine leukemia virus (BLV) as "DNA-targets" for the detection of the BLV proviral DNA. We found that the gp51 and p24 genes of BLV are sufficiently specific to be used as marker sequences in PCR. The bioinformatic analysis of intraspecies specificity was conducted for each primer combination, and as a result, we found that they are complementary to most of the full-genome nucleotide sequences of BLV isolates displayed at NCBI online resources. We were able to show that the designed primer combinations possess high sensitivity, reaching 15 cells/μl in both variants. Furthermore, we compared the PCR method with the suggested primer combinations against other laboratory diagnostic methods, namely BLV-AGID and ELISA. Regarding BLV detection, the PCR method with each primer combination applied to genes gp51 and p24 separately was more effective than both AGID and ELISA; it surpassed the former by 13.5% and 14.4%, respectively, and the latter by 6.1% and 7.0%, respectively. The simultaneous use of both primer combinations on a single amplified mixture showed the largest number of BLV-infected cows (53 animals) compared to the separate amplification of each genetic marker.