Enzootic bovine leucosis

In an analytical discourse reviewed the available data on aspects of enzootic bovine leucosis that are little discussed in the domestic literature. The most important elements of pathobiosis as a transmission of infection and pathogenesis, its cellular and virological mechanisms, proviral load and the practical significance of its measurement, infection of the of newborns and the role of infected young animals in the spread of leucosis are interpreted from the current position of the parasitic system.

BoLA-DRB3 Polymorphism is Associated with Differential Susceptibility to Bovine Leukemia Virus-Induced Lymphoma and Proviral Load

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis. However, less than 5% of BLV-infected cattle will develop lymphoma, suggesting that, in addition to viral infection, host genetic polymorphisms might play a role in disease susceptibility. Bovine leukocyte antigen (BoLA)-DRB3 is a highly polymorphic gene associated with BLV proviral load (PVL) susceptibility. Due to the fact that PVL is positively associated with disease progression, it is believed that controlling PVL can prevent lymphoma development. Thus, many studies have focused on the relationship between PVL and BoLA-DRB3. Despite this, there is little information regarding the relationship between lymphoma and BoLA-DRB3. Furthermore, whether or not PVL-associated BoLA-DRB3 is linked to lymphoma-associated BoLA-DRB3 has not been clarified. Here, we investigated whether or not lymphoma-associated BoLA-DRB3 is correlated with PVL-associated BoLA-DRB3. We demonstrate that two BoLA-DRB3 alleles were specifically associated with lymphoma resistance (*010:01 and *011:01), but no lymphoma-specific susceptibility alleles were found; furthermore, two other alleles, *002:01 and *012:01, were associated with PVL resistance and susceptibility, respectively. In contrast, lymphoma and PVL shared two resistance-associated (DRB3*014:01:01 and *009:02) BoLA-DRB3 alleles. Interestingly, we found that PVL associated alleles, but not lymphoma associated alleles, are related with the anti-BLV gp51 antibody production level in cows. Overall, our study is the first to demonstrate that the BoLA-DRB3 polymorphism confers differential susceptibility to BLV-induced lymphoma and PVL.

Enzootic bovine leucosis in cows on farms in Almaty and Turkestan regions of Kazakhstan

The objective of this study was to evaluate pathomorphological and histopathological characteristics of internal organ tissues and skeletal muscles of Black-Motley cows with bovine laeukemia necropsied between 2013 and 2017. Pathomorphological and histopathological assessment of enzootic bovine leukosis was performed. The viral presence was proved by haematological study, enzyme-linked immunosorbent assay and agar-gel immunodiffusion. There was the pathomorphological manifestation of an immunosuppressive condition in the cattle, as well as leukemic cell accumulations in the brain, kidneys, duodenum, spleen, lymph nodes, cardiac and skeletal muscles. Our study is considered to bear significance concerning the description of microstructural changes involving lymph node trabeculae and myocardial fibres from leukemic cows. This investigation, therefore, provides new knowledge on histopathological features of enzootic bovine leucosis, which potentially may bring new insights into the disease mechanisms.