Toxoplasma gondii in Wild Cervids and Wild Canids: Feeding Ecology, Environmental Exposure, and Trophic Transmission

Toxoplasma gondii is a zoonotic protozoan transmitted by environmentally persistent oocysts and by tissue cysts in infected prey or meat. Although wild cervids and wild canids are increasingly used as wildlife sentinels, their complementary ecological roles in integrated T. gondii surveillance have not been comprehensively synthesized. This structured narrative review compares infection evidence in five wild cervid species and three wild canid species to examine how feeding ecology shapes exposure and to assess their complementary value in wildlife surveillance. Peer-reviewed literature published between 2000 and 2026 was retrieved from PubMed, Scopus, ScienceDirect, and Google Scholar. Studies reporting evidence of T. gondii exposure or infection in wild cervids or wild canids were included, with serological evidence evaluated separately from molecular or histological detection. Cervids showed geographically variable exposure consistent with ingestion of oocysts from contaminated vegetation, soil, and water, supporting their use as sentinels of environmental contamination. Wild canids often showed higher reported seropositivity, although direct comparisons were limited by assay, sampling, and demographic heterogeneity. Their predatory, scavenging, and omnivorous diets allow access to both environmental oocysts and tissue cysts. Cervids and canids should therefore be treated as complementary rather than interchangeable indicators: cervids primarily reflect environmental exposure, whereas canids integrate environmental and trophic transmission. This review provides an ecological framework to support integrated One Health wildlife surveillance by combining environmental and trophic indicators for improved risk assessment and food-safety planning.