If you're deer hunting in an area known to have a lot of feral house cats, you might want to make sure you cook your venison properly.
That's because a new study published in the journal EcoHealth has found that a large percentage of whitetail deer in the greater Cleveland, Ohio, area are infected with a parasite associated with feral domestic cats.
“This study documents the widespread infection of deer populations in northeastern Ohio, most likely resulting from feral cats, and highlights the need for consumers of venison to make absolutely certain that any deer meat planned for consumption is thoroughly and properly cooked,” said Gregory Ballash of the Department of Veterinary Preventive Medicine at Ohio State University and lead author of the study.
Two hundred free-roaming cats and 444 white-tailed deer were tested for the parasite Toxoplasma gondii, which causes toxoplasmosis. Almost 60 percent (261) of the deer showed evidence of infection and more than 65 percent (164) of the studied cats tested positive.
According to the report, approximately 14 percent of the United States’ human population is infected with toxoplasmosis by the age of 40, with an estimated 1 million new cases diagnosed each year. Cats, both domestic and wild (such as bobcats), play a critical role in the spread of toxoplasmosis because they serve as the definitive hosts, fulfilling the requirements needed for the parasite to sexually reproduce and complete its life cycle.
Domestic cats are often infected at less than one year of age. Once infected, they can contaminate the environment by shedding hundreds of millions of infectious eggs (called “oocysts”) via their feces. Free-roaming cats — those that are allowed free access to the outdoors — are more likely to be exposed and infected, thereby contributing more frequently to environmental contamination than indoor cats.
Similar estimates for white-tailed deer infections have been found in Iowa (53.5 -64.2 percent), Pennsylvania (60 percent), Mississippi (46.5 percent), and Ohio (44 percent), suggesting widespread environmental contamination.
The odds of deer from urban locations testing positive for toxoplasmosis were nearly three times those of deer from suburban areas when adjusted for age and gender. The study found that densities of human households, and likely cats, were a significant predictor of infection in deer.
The parasite is believed to infect about one-third of the world’s population and one study has shown a decline in working memory in infected humans over age 65.