Abstract
Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leukosis (EBL) and has worldwide distribution. Infections with BLV have been reported in cattle from Kazakhstan but the virus has not yet been thoroughly characterized. In this study, we detect and estimate the level of BLV proviral DNA by qPCR in DNA samples from 119 cattle naturally infected with BLV, from 18 farms located in four different geographical regions of Kazakhstan. Furthermore, we conducted the phylogenetic and molecular analysis of 41 BLV env-gp51 gene sequences from BLV infected cattle. Phylogenetic analysis showed the affiliation of sequences to two already known genotypes G4 and G7 and also to a new genotype, classified as genotype G12. In addition, a multivariate method was employed for analysis of the association between proviral load and different variables such as the geographical location of the herd, cattle breeds, age of animals, and the presence of particular BLV genotypes. In summary, the results of this study provide the first evidence on molecular characterization of BLV circulating in cattle from Kazakhstan.
Highlights
Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leukosis (EBL), a neoplastic disease of the lymphatic system in cattle
Positive cattle were found in all 18 farms from six regions and the seroprevalence varied from 0.8% to 84.0%, with the highest rate noted among the Pathogens 2022, 11, 180 farms located in East Kazakhstan (40.0–84.0%) (Table 1)
In order to perform molecular analysis of BLV strains circulating in Kazakhstan, blood samples were collected from seropositive cattle and genomic DNA was extracted from PBLs
Summary
Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leukosis (EBL), a neoplastic disease of the lymphatic system in cattle. Gp51 protein contains the T-cell epitopes (CD4+, CD8+, gp51N5, gp51N11, and gp51N12) involved in cellular immunity to BLV [20] In this respect BLV env gene sequences were the main target for phylogenetic studies, leading to the identification of at least 11 BLV genotypes, distributed worldwide [21,22]. We conducted the phylogenetic and molecular analysis of complete BLV env-gp gene sequences in DNA extracted from blood samples of cattle from 18 herds, located in different geographical regions of Kazakhstan. The proviral load was estimated by the use of qPCR and a multivariate statistical method was employed for analysis of the association between proviral load and different variables such as geographical location of the herd, cattle breeds, age of animals and the presence of particular BLV genotypes. This study provides the first evidence on molecular characterization of BLV circulating in cattle from Kazakhstan
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
