Bovine Leukosis Virus
Bovine leukosis virus (BLV) is one of those insidious diseases that can kill cattle and reduce overall productivity of a beef herd, even when there are no obvious signs of infection. In less than 5% of infected cattle, BLV causes malignant lymphoma that leads to cancerous tumors (lymphosarcoma) and death. Most animals don’t die of the disease, but the virus can never be eliminated, and BLV-positive cattle remain a source of infection for other animals. Fortunately, there is no evidence that BLV is transmissible to humans.