OVERVIEW: Toxoplasma gondii infection is common in cats, but the clinical disease is rare. Up to 50% of cats, especially free-roaming ones, have antibodies indicating infection and the presence of cystic stages. DISEASE SIGNS: Clinical signs only appear in few cats when they become immunosuppressed - in these situations cystic stages can be reactivated. Commonly affected are the central nervous system (CNS), muscles, lungs and eyes. HUMAN INFECTION: Cats can pose a risk for humans when they shed oocysts. However, this happens only once in their lifetime, usually only for 3-10 days after ingestion of tissue cysts. Thus, cats that have antibodies to T gondii no longer shed oocysts, and do not pose a risk to humans.