Prevalence of Toxoplasma gondii in retail venison in Montreal detected using a nested PCR method

Toxoplasma gondii is a globally significant zoonotic pathogen responsible for congenital disorders and opportunistic infections, primarily transmitted through foodborne pathways. Deer are considered high-risk hosts for T. gondii infection; however, data on its prevalence in their muscle tissues remain limited. This study assessed the prevalence of T. gondii in 168 fresh venison samples collected in Montreal in 2024. The sensitivity of conventional PCR and nested PCR methods for detecting the RE-529 fragment was compared. Nested PCR exhibited a detection limit of 2 fg/μL, which is 100 times more sensitive than that of conventional PCR. Using nested PCR, T. gondii DNA was detected in 73 out of 168 samples, indicating a high positivity rate of 43.45 %. These findings reveal the widespread prevalence of T. gondii in venison sold in Montreal and emphasize the importance of freezing or thoroughly cooking venison to mitigate the risk of foodborne toxoplasmosis. This study provides baseline data for health risk assessments and contributes to the development of food safety policies in Canada. • The detection limit of nested PCR was 2 fg/μL. • This was the study to assess T. gondii in retail venison in Montreal. • Among 168 venison samples tested, 73 were positive, with a positivity rate of 43.45 %. • Venison should be frozen for a day or thoroughly cooked to reduce T. gondii risk.