Bovine Leukemia Virus molecular detection and associated factors among dairy herd workers in Antioquia, Colombia

The Bovine Leukemia Virus (BLV) affects mainly cattle, is transmitted by exposure to contaminated biological fluids, and generates lymphomas in 5 % of infected animals. The zoonotic potential of BLV has been studied, and it is currently unknown if it circulates in human workers on dairy herds in Antioquia. Objective: To determine the frequency of BLV detection, the genotypes of the virus, and the factors associated with its detection in workers for dairy herds in Antioquia, Colombia. Through a cross-sectional study in 51 dairy herds, 164 adults were recruited. A peripheral blood sample was collected from each participant for molecular detection of the BLV env and tax genes, and associated factors were explored through bivariate and multivariate mixed Poisson model analyses. The analysis showed that 82 % (134/164) of the participants were men, with an average age of 40. Using qPCR, the constitutive gene GAPDH was amplified to evaluate the presence of amplification inhibitors in the DNA samples. Using nested PCR, the amplification of the env viral gene was obtained in 13 % (22/164) of the total samples analyzed, while all the samples tested negative for tax. The amplicons of the env gene were sequenced, and the identity compatible with BLV was verified by BLAST analysis (NCBI). Using molecular phylogeny analysis, based on maximum likelihood and haplotype network analysis, it was identified that BLV genotype 1 is present in the evaluated population. 16 % (26/164) of the participants reported having ever had an accident with surgical material during work with cattle; this variable was associated with BLV positivity even after adjusting for other variables (PRa =2.70, 95 % CI= 1.01- 7.21). Considering that other studies have reported the circulation of BLV genotype 1 in cattle from this same region and the present report in humans from dairy herds, the results suggest a possible zoonotic transmission of BLV genotype 1 in Antioquia, reinforcing the need to continue investigating to determine the potential role of this virus as an etiological agent of disease in livestock farmers in the department.