Well Done or Frozen Venison Prevents Toxoplasmosis Infection

toxoplasmosis venison qdma lead

In the early 1980s, I was one of three South Carolina wildlife biologists who consumed freshly killed venison for dinner following a day of processing several deer. The venison was cooked rare, the way we liked it. Two of us ended up hospitalized for nine days with fevers peaking at 104 degrees daily. Strangely, there were no other symptoms, making it impossible for our doctors to reach an accurate diagnosis. Once our fevers subsided, however, we were discharged from the hospital. Months later, a curious physician from the state health department looked at our blood samples and closed our case with a diagnosis: toxoplasmosis.

Toxoplasmosis is a parasitic disease caused by a tiny organism called a protozoon. This parasite, known as Toxoplasma gondii, is one of the world’s most common parasites. It causes a broad scope of symptoms. They range from asymptomatic (no obvious symptoms), which is probably the most common, to a flu-like condition, and to more serious complications in pregnant women, infants born to infected mothers, and for people with weakened immune systems.

The Source: Cats

How does one “catch” this disease? Many wild and domestic animals can harbor this parasite, but it is the house cat (tame and feral) that is most often associated with human infections. Direct and indirect contact with cat feces provides the pathway for disease transmission. Consuming unwashed and/or undercooked vegetables from a garden frequented by cats is a common indirect method of contracting toxoplasmosis.

Results from a recent Ohio State University study in the metropolitan Cleveland, Ohio area revealed that 60 percent of more than 400 deer tested were infected with toxoplasmosis. This was three times higher than rates in suburban deer, likely due to a higher density of free-ranging or feral house cats in urban areas.

Preventing Infection

The concern with venison consumption from these urban and suburban areas is obvious, but it should be applied throughout the whitetail’s range. For venison lovers, there are several ways to minimize your chances of contracting this common disease. Once the meat has been processed, wash cutting boards, dishes, utensils, countertops, and hands with hot, soapy water. Avoid touching your mouth after handling raw meat.

If you insist on serving your venison with a pink center, make absolutely certain that the meat has been frozen prior to cooking.

It is a long-standing tradition for hunters at a deer camp to prepare fresh venison, especially backstraps and tenderloins, as a celebration meal following a successful hunt. To complicate matters, for many it is sacrilege to grill or pan-fry venison well-done. Therefore, any Toxoplasma parasites that are present will not be killed.

Here’s an important notice to venison lovers. If you insist on serving your venison with a pink center, make absolutely certain that the meat has been frozen prior to cooking. Otherwise, cook meat at a temperature of at least 145 degrees and allow a rest time of three minutes before carving and consuming. During the rest time, the temperature remains constant or continues to rise briefly, which destroys the toxoplasmosis pathogens.

Lifelong Complications

As for my two colleagues and me, none of us have had any complications from the disease since we initially recovered. It is unfortunate, though, that we are not allowed to give blood nor can we serve as organ donors. Toxoplasma antibodies generally persist for life and therefore may be present in one’s bloodstream as a result of either a current or previous infection. There are medications that can help reduce the severity of a toxoplasmosis infection, but the best approach is prevention. Deer hunters are encouraged to keep their hands clean, to always freeze their venison before it is cooked, or to cook it thoroughly. From this point on, no worries!


About Joe Hamilton

Joe Hamilton is a wildlife biologist and the founder of the Quality Deer Management Association (QDMA). During his nearly 20 years with the South Carolina Department of Natural Resources, Joe helped implement QDM practices on more than 2 million acres. In 2000, he was awarded the Deer Management Career Achievement Award from The Wildlife Society. In 2011, he was named Conservationist of the Year by Budweiser Outdoors. He currently serves as Senior Advisor for QDMA.