Dr Dillner's health dilemmas: Should I get rid of my cat to avoid toxoplasmosis?

Any disease that you catch by eating the eggs of a parasite is one that you will want to avoid. Toxoplasmosis is an infection caused by the parasite Toxoplasmosis gondii – the eggs and cysts of which are found in contaminated meat, vegetables and milk, as well as soil and the faeces of cats.

It is estimated that 1% of Britain's eight million cats are infected with the parasite, which has a complicated life cycle that includes multiplying within cats. The Food Standards Authority (FSA) announced this week that more work is needed to identify how common toxoplasmosis is and the main route by which it spreads.

The Health Protection Agency estimates that 7-34% of us have been infected at some point (the estimate is wide as it is not a notifiable disease); about 350,000 people contract it each year. Most (80%) won't notice, but it can be catastrophic.

Some people feel mild flu-like symptoms with aches, headache, fever, enlarged lymph nodes and tiredness. In people with weak immune systems, the infection can cause eye inflammation and blurred vision and the parasite can form cysts in the brain, leading to seizures and confusion. If a pregnant woman gets infected, the parasite can harm her fetus and sometimes lead to stillbirth, so much of the advice about reducing the risk has been aimed at expectant mothers. The FSA says that the risk to others needs to be better evaluated. In the meantime, should you avoid cats?

The solution

A cat can shed up to 10 million cysts a day for two weeks after being infected. You don't need to get rid of your pet but don't put your fingers in your mouth after stroking it and wear gloves if you go near cat faeces. Avoid stray cats as they are more likely to be infected, and feed your cat dried or tinned food rather than raw meat. If you are pregnant, now is not the time to buy a kitten; consider getting someone else to care for any existing cats you may have.

Although it isn't clear where most infections come from, out of 17 reported in the 1990s, 13 were linked to eating raw or rare meat or unpasteurised goat's milk. Other studies suggest uncooked meat is the biggest risk factor for pregnant women. Eating pink lamb is also thought to carry a risk, so cook meat until the juices run clear and do not put your fingers in your mouth while preparing it. Also avoid uncooked meats – even the curing of meat may not completely kill the parasite. Wash fruit and salads thoroughly to get rid of any cysts from contaminated soil and wear gloves when gardening.

Toxoplasmosis can be diagnosed by a blood test but there is no vaccine for pets. However, for people who are infected and have symptoms there are drugs available, such as pyrimethamine, which is also used to treat malaria, and sulfadiazine.