Toxoplasmosis refers to infection with the parasite Toxoplasma gondii. Cats are important in the lifecycle and transmission of this parasite and humans can also be infected. As a result, headlines and press articles appear from time-to-time suggesting the role of this parasite in human disease and often implicate cats as the major source of infection. Unfortunately, such articles often misrepresent the true situation or fail to provide a full and balanced picture.
- Most human infections with T gondii cause no disease or only mild 'flu'-type symptoms
- Toxoplasmosis can be severe, especially in certain 'high-risk' groups of humans, including unborn babies, infants, elderly people and those with suppressed immune systems
- In most countries, the majority of human infections are thought to occur through the ingestion of undercooked meat, which may contain forms of the organism in 'tissue cysts'
- Infection can also be acquired through the ingestion of oocysts (eggs) shed in the faeces of cats. This can occur through poor hygiene (eg, children not washing hands after playing in soil/sand, or failure to wash vegetables before consumption)
- Oocysts are only shed for a very limited time (1-2 weeks) after a cat is first infected with T gondii. Further, only a minority of pet cats are infected so it is rare to find a pet cat that is shedding oocysts
Most studies suggest that:
- Owning a cat does not in itself increase the risk of toxoplasmosis in the owner
- Veterinarians working with cats are also no more likely to be infected with T gondii
- Stroking a cat will not spread infection as oocysts are not found on the coat
- The risk of infection from cats is low except in young children playing in contaminated soil
- Oocysts in cat faeces require 2-3 days to 'sporulate' before they are infective
Simple hygiene precautions dramatically reduce the risk of toxoplasmosis in humans, including:
- Clean and wash all food preparation surfaces and utensils before and after use
- Cook meat thoroughly to kill the tissue cysts
- Wear gloves when gardening and washing hands after contact with soil
- Wash fruit and vegetables thoroughly before cooking and eating
- Wash hands after handling fruit and vegetables
- Periodically clean the litter tray with detergent and scalding water
- Dispose of cat litter safely (eg, sealed in a plastic bag with household waste)
- Empty cat litter trays daily so if oocysts were present they would not be infective.
- Wear gloves when handling cat litter and wash hands after cleaning the litter tray
- People in 'high-risk' groups should avoid contact with the cat's litter tray
- Cover children’s sandpits when not in use to prevent cats using them as litter trays
- Feed only properly cooked food or commercial cat food to your cat to avoid infection
In summary, the risks of acquiring toxoplasmosis directly from a cat are extremely small, and most people are infected in other ways, especially by eating undercooked meat. International Cat Care supports the recent report from the Advisory Committee on the Microbiological Safety of Food in calling for more data and a better understanding of the risks from food consumption and environmental contamination in the UK. However, simple everyday hygiene measures dramatically reduce the risks of infection, and make it both safe and enjoyable to own a cat.
For full information, see The Cat Group Policy Statement on Toxoplasmosis