A recently published study looked at the prevalence of Taxoplasma gondii in retail meat samples in Scottland. (
Detection of Toxoplasma gondii in retail meat samples in Scotland, FWP 2020). Results were that "Toxoplasma gondii DNA was detected in 0/39 (0%) beef samples, 1/21 (4.8%) chicken samples, 6/87 (6.9%) lamb samples, 3/71 (4.2%) pork samples and 29/82 (35.4%; Sampling Period 1) and 19/67 (28.4%; Sampling Period 2) venison samples." The researchers state "This is the first study to report the presence of T. gondii in retail meat products in Scotland and has highlighted venison as a potentially high risk meat."
So, what is the risk for those eating venison? In 2017, a Wisconsin outbreak was investigated at a hunting camp and in that invesigation, it was believed to be related to undercooked venison. In this paper, the author points out other outbreaks involving venison, "In 4 other studies of suspected venison-transmitted toxoplasmosis, consumption of undercooked or raw venison was reported [
28–31]. In a follow-up study of the coworkers of the patients in one report, T. gondii seropositivity was significantly associated with having eaten raw or rare venison [31]. Another of the reports describes a toxoplasmosis outbreak among a group of healthy male Canadian hunters who consumed undercooked venison in Illinois, USA [28]. The Canadian outbreak is almost identical to this outbreak in attack rate, incubation period, symptom severity, and the inclusion of one seronegative but presumed exposed individual. As Wisconsin and Illinois share a border, it is possible that similar strains of T. gondii caused the outbreaks. "
Taxoplasma gondii tissue cysts are not overly heat resistance. (
link). "At 61 C (142F) the cysts were generally inac tivated instantaneously as a result of the come up time (2 min) and come-down time (1.5 min)."
But if people follow the recommendation for cooking meats, especially wild meats where the potential for contamination may be higher in that the diet is not controlled, cooking to medium should easily achieve this goal.