Effectiveness of integrated bovine leukemia virus eradication strategies utilizing cattle carrying resistant and susceptible histocompatibility complex class II DRB3 alleles

Bovine leukemia virus (BLV) has spread worldwide and causes serious problems in the cattle industry owing to lack of effective treatments vaccines. BLV is transmitted via horizontal vertical infection, with high proviral load (PVL), which a useful index for estimating disease progression transmission risk, are considered major infectious sources within herds. PVL strongly correlates highly polymorphic bovine lymphocyte antigen (BoLA)-DRB3 alleles. The BoLA-DRB3*015:01 *012:01 alleles known susceptibility-associated markers related PVL, susceptible may be at risk direct contact healthy cows. In contrast, BoLA-DRB3*009:02 *014:01:01 comprise resistant associated development low low-risk spreaders disrupt chain. However, whether polymorphisms BoLA-DRB3 eradication farms remains unknown. Here, we conducted validation trial integrated strategy prevent new infection by actively eliminate addition conventional strategies maximally reduce prevalence using total 342 4 stall barn Japan from 2017 2019. First, placed milking between BLV-positive -negative 3 years. Interestingly, proved an biological barrier successfully block infections system among all farms. Concomitantly, eliminated especially cattle. Indeed, 39 60 (65%), 76 140 neutral (54%), 20 40 (50%) were culled on Consequently, mean decreased particular, one farm achieved BLV-free status May 2020. By decreasing number animals, revenue-enhancing effect was estimated \5,839,262 over Our results suggest that program utilization as preferential elimination control.