Around 50 per cent of all outdoor cats have been infected with Toxoplasma gondii at some point in their lives. This parasite can cause developmental problems to the growing human foetus, including blindness and increased risk of developing allergies and asthma.
A few days after a cat has been infected for the first time by eating meat containing the parasite it will start to shed millions of eggs in its faeces, for around 14 days, before the body's immune response stops further egg production. These eggs or ‘oocysts’ can survive in the soil or water for up to 18 months even in extreme weather conditions.
Other animals, including our livestock become infected through swallowing sporulated oocysts, and this infection results in formation of tissue cysts in various tissues of the body. We contract the infection by contact with oocysts in the cat’s faeces or much more commonly by eating meat containing these oocysts.
The fetuses of women who have not been infected prior to pregnancy are particularly vulnerable to T gondii-induced disease if the mother is infected when pregnant. Effects of infection are most severe when infection occurs between months two and six of gestation. If a woman already has antibodies to T gondii before she becomes pregnant there is no risk that the infection can be passed on to the fetus.
Contact with cats has no influence on the probability of people having antibodies to T gondii (antibodies develop following infection). Consuming raw meat does. That’s why 20 per cent of people in the UK have antibodies to toxo while 80 per cent of French and Germans, who eat more raw or undercooked meat do. Vets working with cats don’t have a higher incidence of protective antibodies than the general population including people not in contact with cats. Stroking a cat will not spread infection from cats to people.
Reduce Risks From Toxo
Toxoplasmosis is more likely to be contracted from eating undercooked meat than from contact with cat faeces during the two week period the parasite is viable after the cat’s first consumption of contaminated wildlife. Reduce risks in these ways.
- Wear gloves and wash your hands after handling raw meat.
- Eat only thoroughly cooked meat or meat that has been smoked, cured or frozen for at least three days.
- Wash vegetables and fruit thoroughly before eating.
- Wear rubber gloves when gardening.
Although the risk of direct transmission of infection from a house cat to a person is very low, this can be reduced further in the following ways.
- Keep cats off kitchen work surfaces.
- Wear gloves when cleaning the cat’s litter tray or get someone else to do it.
- Dispose of cat litter safely by sealing it in a plastic bag before putting it with other household waste.
- 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.
If you are very concerned, ask us to check your cat's toxoplasma titre. Cats with a positive titre have been infected in the past and will not be a source of infection in the future as they have completed their period of oocyst shedding.