Toxoplasmosis is a zoonotic parasite with complex welfare implications for cats, infected wildlife, and the ecosystem effects of free-roaming cat predation combined with parasite shedding.
Toxoplasmosis has welfare implications across multiple species simultaneously. For cats, primary infection is usually subclinical but can cause illness in immunocompromised individuals including kittens and FIV-positive cats. Wildlife welfare is affected through both direct infection causing neurological disease and the behavioral manipulation hypothesis — Toxoplasma may alter rodent behavior in ways that increase predation risk, which could be interpreted as a welfare-relevant behavioral modification. Marine mammal welfare is affected by coastal cat fecal contamination, with toxoplasmosis causing severe neurological disease in sea otters. The systemic approach to toxoplasmosis management — indoor cat keeping, proper litter hygiene, preventing cat access to coastal watersheds — serves simultaneously the welfare interests of cats, wildlife, and public health.