Co-Circulation of Bovine Leukemia Virus Haplotypes among Humans, Animals, and Food Products: New Insights of Its Zoonotic Potential

Abstract

Bovine leukemia virus (BLV) is the causative agent of leukemia/lymphoma in cattle. It has been found in humans and cattle-derived food products. In humans, it is described as a potential risk factor for breast cancer development. However, the transmission path remains unclear. Here, a molecular epidemiology analysis was performed to identify signatures of genetic flux of BLV among humans, animals, and food products. Sequences obtained from these sources in Colombia were used (n = 183) and compared with reference sequences available in GenBank. Phylogenetic reconstruction was performed in IQ-TREE software with the maximum likelihood algorithm. Haplotype (hap) distribution among the population was carried out with a median-joining model in Network5.0. Recombination events were inferred using SplitsTree4 software. In the phylogenetic analysis, no specific branches were identified for the Colombian sequences or for the different sources. A total of 31 haps were found, with Hap 1, 4, 5 and 7 being shared among the three sources of the study. Reticulation events among the different sources were also detected during the recombination analysis. These results show new insights about the zoonotic potential of BLV, showing evidence of genetic flux between cattle and humans. Prevention and control strategies should be considered to avoid viral dissemination as part of the One Health program policies.

In vitro Susceptibility of Human Cell Lines Infection by Bovine Leukemia Virus

“…Both conditions seem to be important in the progression of the disease in its host ( Lairmore, 2014 ). This result is significant as it provides in vitro experimental evidence consistent with the hypothesis of BLV as an exogenous etiological agent of human breast cancer, obtained through a zoonotic infection ( Corredor-Figueroa et al, 2021 ). Nevertheless, the varying susceptibility and capacity of maintaining a stable infection of BLV in human cell lines as well as from other mammal species opens new questions in BLV research in which further studies are needed toward the characterization of the mechanisms involved in BLV infection in other hosts than cattle.…”

“…Therefore, concerns about the zoonotic potential of BLV have been present for some time in the BLV research, and for several years, researchers have tried to show the implications of BLV in human beings ( Burridge, 1981 ; Burny et al, 1985 ; Buehring et al, 2003 ). In early BLV research, it was not possible to identify any relationship between humans and BLV ( Burridge, 1981 ), but now there is increasing evidence about the presence of the virus in human beings, strengthening the hypothesis of BLV being a zoonotic agent ( Cuesta et al, 2018 ; Buehring and Sans, 2020 ; Canova et al, 2021 ; Corredor-Figueroa et al, 2021 ).…”

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

“…Infectious BLV is present in the colostrum and milk of most BLV-positive cows [ 259 , 260 ]. Recent evidence points to a genetic flux between cattle and humans [ 261 ]. Olaya-Galán et al [ 262 ] detected BLV DNA in raw beef and fresh milk for human consumption reminiscent of findings on BMMF distribution.…”

Evidence of bovine leukemia virus circulating in sheep and buffaloes in Colombia: insights into multispecies infection

“…The presence of BLV in multiple species, its high prevalence rate (62%) in cattle in Colombia [40], and the potential for co-circulation of the virus in cattle and humans [33] should raise concerns for regulatory agencies and livestock producers, as BLV infections are unfavorable for the animal production sector [16,17], and the zoonotic potential of the virus has implications for human health [31,74]. Accumulating evidence in the literature suggesting that BLV can infect multiple species should raise concerns about elevated dissemination rates on mixed-species farms, in wildlife reservoirs, and in accidental hosts, which could hamper prevention and control strategies to stop the spread of the virus.…”

“…In addition, BLV has been found in breast tissue [26,27], lungs [28], and blood [29] of humans, suggesting the occurrence of zoonotic infections, which might be associated with cancer development [30][31][32]. Recently, co-circulation of the virus among humans and cattle was also reported, with evidence of transfer of molecular signatures and genetic flux between species [33]. This suggests that food products obtained from infected cattle could be a potential source of viral dissemination and zoonosis [34].…”