Prevalence and molecular epidemiology of bovine leukemia virus in Colombian cattle

Bovine leukemia virus (BLV) is one of the five agents considered most significant for cattle. It is important to determine the prevalence and molecular epidemiology of BLV throughout the country in order to gain a more thorough understanding of the current situation of BLV and to reveal the possibility of masked genotypes that the primers used by OIE are unable to identify. Blood samples were collected at random from 289 cows distributed in 75 farms across the country. PCR amplification of env, gag and tax gene segments was performed. The obtained amplicons were sequenced and then subjected to phylogenetic analyses. A total of 62% of the cows present at 92% of the farms were BLV-positive for gag fragment. Genotype 1 was exclusively detected by env gene segment when analyzed using previously reported primers. However, tax gene analysis revealed circulation of genotype 6 variants, which were also detected based on env gene analysis with newly designed primers. These results indicate that current genotyping approaches based on partial env sequencing may bias BLV genetic variability approaches and underestimate the diversity of the detected BLV genotypes. This report is one of the first molecular and epidemiological studies of BLV conducted in Colombia, which contributes to the global epidemiology of the virus; it also highlights the substantial impact of BLV on the country's livestock and thus is a useful resource for farmers and government entities

Bovine leukaemia virus DNA in fresh milk and raw beef for human consumption

Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leucosis, which has been reported worldwide. BLV has been found recently in human tissue and it could have a significant impact on human health. A possible hypothesis regarding viral entry to humans is through the consumption of infected foodstuffs. This study was aimed at detecting the presence of BLV DNA in raw beef and fresh milk for human consumption. Nested PCR directed at the BLV gag gene (272 bp) was used as a diagnostic test. PCR products were confirmed by Sanger sequencing. Forty-nine per cent of the samples proved positive for the presence of proviral DNA. This is the first study highlighting the presence of the BLV gag gene in meat products for human consumption and confirms the presence of the viral DNA in raw milk, as in previous reports. The presence of viral DNA in food products could suggest that viral particles may also be found. Further studies are needed to confirm the presence of infected viral particles, even though the present findings could represent a first approach to BLV transmission to humans through foodstuff consumption. Copyright © Cambridge University Press 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited

Risk factor for breast cancer development under exposure to bovine leukemia virus in Colombian women : A case-control study

Q2Q1Viruses have been implicated in cancer development in both humans and animals. The role of viruses in cancer is typically to initiate cellular transformation through cellular DNA damage, although specific mechanisms remain unknown. Silent and long-term viral infections need to be present, in order to initiate cancer disease. In efforts to establish a causative role of viruses, first is needed to demonstrate the strength and consistency of associations in different populations. The aim of this study was to determine the association of bovine leukemia virus (BLV), a causative agent of leukemia in cattle, with breast cancer and its biomarkers used as prognosis of the severity of the disease (Ki67, HER2, hormonal receptors) in Colombian women. An unmatched, observational case–control study was conducted among women undergoing breast surgery between 2016–2018. Malignant samples (n = 75) were considered as cases and benign samples (n = 83) as controls. Nested-liquid PCR, in-situ PCR and immunohistochemistry were used for viral detection in blood and breast tissues. For the risk assessment, only BLV positive samples from breast tissues were included in the analysis. BLV was higher in cases group (61.3%) compared with controls (48.2%), with a statistically significant association between the virus and breast cancer in the unconditional logistic regression (adjusted-OR = 2.450,95%CI:1.088–5.517, p = 0.031). In this study, BLV was found in both blood and breast tissues of participants and an association between breast cancer and the virus was confirmed in Colombia, as an intermediate risk factor.https://orcid.org/0000-0002-0084-0339Revista Internacional - IndexadaS