Toxoplasmosis is a common infection caused by a single-celled parasite. The parasite is found all over the world in many species of animals, but especially in domestic cats. It can also be found in water, vegetables and soil that have become contaminated, and in raw meat.
It is estimated that between 16 and 40 per cent of people in the UK have had toxoplasmosis, but most do not have any symptoms and never know they are infected, as a healthy immune system usually keeps the parasite from causing any illness.
Anyone can get toxoplasmosis. But people who have weakened immune systems, including patients with cancer or AIDS, or who have had an organ transplant, and unborn babies are at a greater risk of developing serious illness (see complications).
You can become infected with the parasite by:
Accidentally swallowing infected cat faeces. This might happen if you touch your hands to your mouth after gardening, cleaning a cat's litter tray, or touching anything that has come into contact with cat faeces
Eating, or contact with, contaminated, raw, or partly cooked meat (especially pork, lamb, or venison)
Eating food that has been in contact with contaminated raw meat, knives, utensils, cutting boards, or other contaminated food
Drinking contaminated water
Receiving an infected organ transplant or blood transfusion, though this is rare.
You cannot give toxoplasmosis to other people through casual or intimate contact, or by coughing and sneezing into the air.
There is no vaccination for toxoplasmosis. You can avoid the risk of becoming infected with toxoplasmosis by :
Washing your hands and all cooking utensils and surfaces after preparing raw meat
Always wearing gloves when gardening. Remembering to thoroughly wash hands after gardening and before eating or drinking
Protecting children's sandpits and play areas from cats
Changing the cat litter on a daily basis. This removes the microscopic eggs, or oocysts, before they have a chance to mature and become infectious. These are shed in the faeces. Rinsing the tray with boiling water will also kill the parasites. Wear gloves when handling soiled cat litter
Avoiding raw or undercooked meat, particularly if you are pregnant
Avoiding unpasteurised goat milk and products
In most cases of toxoplasmosis there are no symptoms, because the immune system successfully destroys the parasite.
If you do get symptoms they may take up to three weeks to appear. In healthy adults symptoms can easily be confused with a mild `flu. Occasionally people will suffer from a more severe illness with fever, headaches, nausea, muscle and joint aches.
Treatment is not usually necessary, and most people make a full recovery. People with a weakened immune system, pregnant women, and those whose eyes are affected may be given antibiotics.
Severe cases of toxoplasmosis are more likely in people with weakened immune systems. It can cause damage to the eye, brain, and other organs.
Damage can be caused to the retina (the light sensitive area at the back of your eye) and damage can occur here without the affected person realising. If someone gets toxoplasmosis several times, further permanent change to the eye can take place, but it is only when the central part of the retina becomes damaged that the people experience loss of vision and realise that something is wrong.
If pregnant women become infected, their unborn baby can be affected because its immune system is not able to fight off the infection. There is a risk of miscarriage or stillbirth if the infection is caught during the first three months of pregnancy. Babies infected while still in the womb may have no symptoms at birth, but may go on to develop symptoms during the first few months of life.
There is no need to stay away from school or work if you have toxoplasmosis.
More information about the Health Protection Agency and about toxoplasmosis is available on our website www.hpa.org.uk.
If you have concerns about your health contact NHS Direct on 0845 4647 or visit their website www.nhsdirect.nhs.uk, or see your family doctor.
This factsheet can also be toxoplasmosis (PDF, 209 KB)
Last reviewed: 27 April 2009