Bovine tuberculosis in Michigan: The work on the wildlife side

In 1975 and again in 1994, bovine tuberculosis (TB) was diagnosed in a free-ranging white-tailed deer taken by a hunter in the Michigan’s Northeast Lower Peninsula. In subsequent testing of deer, it was clear that deer were not spillover hosts but, in fact, the infection was being sustained in the deer population. While bovine TB had been detected elsewhere in wildlife, this was the first time in North America that bovine tuberculosis was shown to be sustained in wildlife. While TB had no discernible effect on deer populations, it apparently provided a reservoir of infection to cattle. In 1998, TB was detected in cattle herds, which eventually prompted the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) Veterinary Services (VS) to reduce Michigan’s TB status. The reduced status places significant burdens on producers selling cattle interstate. While VS has considerable experience and success in eradicating TB from cattle, eradicating TB from wildlife presents a very new scientific and social challenge. This paper outlines the progress of eradication efforts undertaken by Michigan Department of Natural Resources and USDA-APHIS–Wildlife Services (WS). Methods used include reducing deer numbers through hunting, regulating the feeding and baiting of deer, special permit shooting, barriers, and a 2004 pilot project that identifies and removes suspected TB-positive deer.