Mycobacterium bovis is endemic in Michigan's whitetailed deer and has been circulating since 1994. The strain circulating in deer has remained genotypically consistent and was recently detected in 2 humans. We summarize the investigation of these cases and confi rm that recreational exposure to deer is a risk for infection in humans.H istorically, Mycobacterium bovis infection in humans was associated with consumption of unpasteurized milk and dairy products (1,2) and this is still the most important route of exposure in developing countries. US populations are exposed to unpasteurized dairy products imported from countries where M. bovis is prevalent (3,4). M. bovis infection in humans is of concern to health officials in Michigan because of to its endemicity in the state's wild white-tailed deer population and its discovery in several cattle herds. M. bovis in deer represents possible occupational and recreational routes of exposure to humans, especially for hunters, trappers, taxidermists, venison processors, and venison consumers (5).Although M. bovis is a zoonotic agent, surveillance indicates no increase in its incidence in Michigan residents since an outbreak began in 1994. Since 1995, the incidence rate of M. bovis infection in Michigan residents has remained very low, with ≈1 new case per year for a total of 13. No genetic or epidemiologic link to the deer/cattle outbreak strain has been identifi ed among 11 of these human M. bovis cases, based on restriction fragment-length polymorphism analysis, spoligotyping, or mycobacterial interspersed repeat units (MIRU) typing (M. Wilkins, unpub. data,