Enzootic Bovine Leukosis; Disease Overview and Current Control Measure
Measures and Issues Concerning Enzootic Bovine Leukemia in Beef Cattle on Miyagi Prefecture
2024 Volume 28 Issue 2 Pages 101-107
Details
2024 Volume 28 Issue 2 Pages 101-107
Enzootic bovine leukosis (EBL) is caused by infection with bovine leukemia virus (BLV), which accounts for the majority of bovine lymphomas. A small percentage of BLV-infected cattle develop EBL, a B-cell lymphoma, after an asymptomatic period lasting months to years. Once EBL develops, there is no effective treatment, and the disease leads to death. Currently, there is no vaccine to prevent BLV infection or EBL. The only way to prevent EBL is by enforcing strict biosecurity measures to control BLV spread. To work toward BLV eradication, it is necessary to identify individual cattle infections and assess the severity of infection, allowing for the prioritization of isolation and culling. Blood testing is essential for this but creates an economic burden for farmers.
In Miyagi Prefecture, the number of reported EBL cases increased from 4 in 2002 to 176 in 2023. In the same year, 137 cattle were recorded as EBL-related deaths in the livestock mutual aid, with compensation totaling approximately 100 million yen. Of these, 42 cattle were diagnosed with EBL on farms, while 95 were detected at slaughterhouses, where the entire carcasses were condemned, indicating more cases were identified after slaughter.
Miyagi Prefecture’s Livestock Hygiene Service Centers and the Miyagi Prefecture Agricultural Mutual Aid Association have been carrying out pilot BLV control measures. However, the number of farms participating in these measures is small compared to the total number of farms in the prefecture, and many farms were able to continue these measures because testing was free or subsidized.
To reduce EBL cases throughout the prefecture, reducing BLV-infected cattle is important, and BLV control measures must be implemented at a prefecture-wide level. However, unlike the previous pilot programs, prefecture-wide implementation would bring costs for farmers, making subsidies or other financial measures necessary.
In July 2024, the “Working Group on Enzootic Bovine Leukosis in Miyagi Prefecture” was established by Miyagi Prefecture, the Zen-Noh Miyagi headquarters, and the Miyagi Prefecture Agricultural Mutual Aid Association. Discussions on practical BLV control measures are expected to proceed.
