Toxoplasma gondii uses cats as its definitive host. Understanding transmission, prevention, and welfare implications helps owners protect both their cats and themselves.
Most cats infected with Toxoplasma show no clinical illness — they are asymptomatic carriers. However, cats with compromised immunity (from FIV, FeLV, or immunosuppressive medication) can develop severe systemic toxoplasmosis with neurological, respiratory, and ocular disease causing significant suffering. The welfare concern for the general cat population is indirect: fear of toxoplasmosis leads some communities to advocate for cat culls or bans that cause mass suffering. Responsible ownership — keeping cats indoors or in managed outdoor spaces, providing commercial food rather than raw meat, and regular vet checks — reduces transmission risk without harming cat welfare. Pregnant women and immunocompromised individuals should have others handle litter trays as a precaution.