Research overview: felids as the definitive host of Toxoplasma and the ecology of oocyst shedding

Cats, both domestic and wild, are the only definitive hosts in which Toxoplasma gondii completes sexual reproduction and sheds environmentally resistant oocysts. This overview surveys the ecology of that shedding: how a cat becomes infected by eating cysts in prey, sheds millions of oocysts over a short window, and seeds the environment for years. It examines how oocyst output from felid populations drives infection in intermediate hosts ranging from rodents to humans to marine mammals, and how factors like cat density, age and immune status shape shedding. The synthesis connects feline behavior and demography to landscape-scale parasite contamination. It aims to explain why understanding cats as the linchpin of the Toxoplasma life cycle is essential to interpreting the parasite’s enormous global footprint.