Cat Toxoplasmosis and One Health Welfare

Toxoplasmosis links cat welfare, human health, and wild animal welfare through a complex parasite life cycle that raises important One Health welfare considerations.

Key Facts

Toxoplasma gondii uses cats as definitive hosts, with rodents and other warm-blooded animals as intermediate hosts.
The parasite alters behaviour of rodent intermediate hosts — reducing fear of cats — to facilitate predation and parasite completion.
Outdoor cats that hunt prey are the primary source of environmental contamination with oocysts.
Toxoplasmosis is a serious risk to immunocompromised humans and developing foetuses from primary infection during pregnancy.
Marine mammals including sea otters and seals die from Toxoplasma infection originating from cat oocyst runoff into waterways.

Welfare Considerations

Toxoplasmosis illustrates the One Health principle that human, animal, and ecosystem welfare are interconnected. Cat hunting behaviour supports parasite transmission that alters the behaviour and welfare of prey species, contaminates waterways that cause mortality in marine mammals, and poses health risks to vulnerable humans. Indoor management of cats, or containment that prevents hunting, reduces all of these welfare and health costs simultaneously without compromising cat welfare when adequate enrichment is provided.

What You Can Do

Keep cats indoors or prevent hunting through appropriate containment to reduce toxoplasma environmental contamination.
Cover children's sandboxes to prevent cat defecation and toxoplasmosis oocyst contamination.
Immunocompromised individuals and pregnant women should avoid handling cat litter or take appropriate precautions.
Support research into toxoplasmosis ecology and its effects on wildlife welfare in marine and terrestrial ecosystems.