Deer hunters in areas with large feral cat populations are being encouraged to thoroughly cook their venison to avoid danger of infection from a parasite. According to an Ohio State University study published in the journal EcoHealth, researchers took tissue samples from 444 deer and 200 free-roaming cats in the greater Cleveland area. Sixty percent of the deer and more than 65 percent of the cats tested positive for Toxoplasma gondii, the parasite that can infect humans with toxoplasmosis. This disease causes flu-like symptoms, brain or eye damage, and possibly schizophrenia and suicidal behavior in humans, according to Cleveland.com.
The parasite can infect all warm-blooded animals, but members of the felid (cat) family are its primary hosts. It is deposited on the ground along with cat feces and can remain infectious for up to 18 months.
Other studies have shown whitetails in Iowa, Pennsylvania, and Mississippi to be infected with toxoplasma gondii. Urban deer have been shown to have three times the odds of being infected as deer in suburban areas, probably because of the greater density of free-roaming domestic cats around cities.