Preventing the Establishment of a Wildlife Disease Reservoir: A Case Study of Bovine Tuberculosis in Wild Deer in Minnesota, USA

Bovine tuberculosis (bTB) has been found in 12 cattle operations and 27 free-ranging white-tailed deer (Odocoileus virginianus) in northwestern Minnesota, following the state's most recent outbreak of the disease in 2005 in the northwest part of the state. Both deer and cattle have the same strain of bTB. The Minnesota Board of Animal Health has been leading efforts to eradicate the disease in Minnesota's cattle, which have included the depopulation of all infected herds, a cattle buy-out program, and mandatory fencing of stored feeds. The Minnesota Department of Natural Resources began surveillance efforts in free-ranging white-tailed deer in fall 2005. All bTB-infected deer have been found within a 16 km(2) area in direct association with infected cattle farms. Aggressive efforts to reduce deer densities through liberalized hunting and sharpshooting have resulted in a 55% decline in deer densities. Also, recreational feeding of wild deer has been banned. Disease prevalence in deer has decreased from 1.2% in 2005 to an undetectable level in 2010.