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Toxoplasmosis life cycle
Cats are the primary host of Toxoplasma gondii (T. gondii), the organism that causes toxoplasmosis. When a cat eats prey infected by T. gondii, the organism invades cells in the walls of the cat's small intestine and forms oocysts. The cat eliminates these cells in feces, deposited in the soil. Other animals become infected by ingesting soil that contains oocytes, millions of which may be passed in a single stool. In these intermediate hosts, T. gondii forms inactive cysts that lodge mainly in the brain or muscles, usually without causing illness.