Enzootic Bovine Leukosis (EBL) is a chronic and contagious viral disease primarily affecting cattle, caused by the retrovirus known as bovine leukemia virus (BLV). It is characterized by the proliferation of B-lymphocytes, a type of white blood cells, resulting in the development of tumors, immunosuppression, and various clinical manifestations.
EBL is typically found in dairy and beef cattle populations worldwide, with higher prevalence reported in certain regions. The primary mode of transmission is through direct contact with infected animals, predominantly through the transfer of infected blood or milk, but can also occur vertically from an infected mother to her calf during pregnancy or at birth.
Signs and symptoms of EBL can vary greatly, ranging from no apparent clinical signs to severe manifestations such as weight loss, decreased milk production, enlarged lymph nodes, anemia, and in rare cases, lymphosarcomas (tumors) affecting various organs. Infected animals may remain asymptomatic for several years, acting as carriers and spreading the virus within the herd.
Diagnosis of EBL involves detecting the presence of BLV-specific antigens or antibodies in the blood, most commonly using serological tests like enzyme-linked immunosorbent assay (ELISA) or agar gel immunodiffusion (AGID).
There is currently no specific treatment for EBL, and control measures mainly focus on preventing the introduction and spread of the virus within herds through maintaining strict biosecurity measures and implementing herd testing and culling of infected animals. Vaccines against BLV are available in some countries but are not widely used.
Overall, EBL poses a significant economic burden due to decreased productivity and potential restrictions on trade of infected animals or their products.
