Toxoplasma gondii is a parasite for which cats are the definitive host, and responsible management of cat faeces reduces transmission risk to humans, other animals, and wildlife.
Toxoplasmosis creates welfare concerns across species: infected birds and rodents undergo behavioural manipulation (loss of fear of cat odour) that increases predation — a welfare harm to prey animals. Wildlife exposed to toxoplasmosis through environmental contamination from cat faeces suffer neurological disease and die. Sea otters, dolphins, and other marine mammals in coastal areas near high cat density areas are affected by watershed toxoplasmosis transmission. Responsible management — covering children's sandpits, composting garden soil carefully, and preventing cats from defecating near water courses — reduces environmental transmission. These interventions require no sacrifice of cat welfare but meaningfully protect other species.