Cause
Infection occurs via ingestion of tissue cysts or infective oocysts. There is an increased risk of infection and clinical disease for unborn or immunocompromised animals. Feline leukemia virus, feline immunodeficiency virus, feline infectious peritonitis, blood parasites, steroids, and chemotherapy can severely compromise the cat's ability to fight off a toxoplasmosis infection. Sources of tissue cysts and oocysts include undercooked meat, unpasteurized milk, contaminated water sources, soil or sandboxes contaminated with feces, flies, rodents, earthworms, and the litter boxes of infected cats.