Bovine tuberculosis in Canadian wildlife: an updated history.

Mycobacterium bovis infection in wild animals attracted little attention in Canada until the disease was almost eliminated from domestic livestock. Tuberculosis was endemic in plains bison and occurred in elk, moose, and mule deer in Buffalo National Park (BNP), Alberta during the 1920s and 1930s. Bison were moved from BNP to Wood Buffalo National Park (WBNP), where tuberculosis became, and remains, endemic in bison, posing a risk to efforts to restore bison in northern Canada. Tuberculosis was found in a white-tailed deer in Ontario in 1959, and in an infected elk near Riding Mountain National Park (RMNP), Manitoba in 1992. Intense surveillance has resulted in detection of 40 elk, 8 white-tailed deer, and 7 cattle herds infected between 1997 and 2008 in the RMNP area. The strains of M. bovis in the RMNP area are different from strains tested from cattle and bison elsewhere in Canada. Management of tuberculosis in cattle and wild animals is challenging because of uncertainty about the ecology of the disease in various species, difficulty in obtaining samples and population data from wildlife, lack of validated tests, overlapping jurisdictions and authority, and conflicting values and opinions among stakeholders.