Tularemia, a disease that can affect both animals and humans, is caused by a bacterium, Francisella tularensis. Although many wild animals are infected (hares, rabbits, squirrels, muskrats, beavers, deer), occasionally certain domestic animals can be infected (sheep and cats). The rabbit is the species most often involved in disease outbreaks. The bacteria can also be found in ticks and deerflies. Tularemia in humans is relatively rare in Wisconsin, averaging less than one case per year since 1980.
Hunters, trappers, or other people who spend a great deal of time outdoors are at a greater risk of exposure to tularemia than people with other occupational or recreational interests.