Definition Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii, also known as T. gondii.
What is going on in the body? Toxoplasmosis is found worldwide, and can infect most species of warm-blooded animals. It is often found in cats. Once infected, a cat will excrete the parasite in its faeces for a few weeks. The parasite in the faeces needs 1 to 2 days to mature before it can infect other animals. Once mature, the parasite causes infection and forms cysts in the tissues of the animal that eat the faeces. People can acquire T. gondii by eating undercooked meats with the cysts or by swallowing the parasite in dirt or foods contaminated with cat faeces.
What are the signs and symptoms of the infection? Usually this disease has no symptoms. When they do occur, they can include:
fever
sore throat
muscle aches
nausea
swollen lymph nodes
rash
enlarged liver and spleen
Rare complications include inflammation of the heart muscle, called myocarditis, inflammation of the sac that envelops the heart, called pericarditis, and inflammation of the lungs, called pneumonitis. People with damaged immune systems, such as those with HIV, can have more severe infections, such as an infection of the brain, called encephalitis.
Although the disease is usually not serious for children and adults, it can be very harmful if a woman passes it to her foetus during pregnancy. This can happen if the mother becomes infected while pregnant. There usually are no symptoms of toxoplasmosis in a baby before it is born. But sometimes at birth, these babies can be quite ill with rash, swollen lymph nodes, enlarged liver and spleen, yellowing of the skin, eyes, and other tissues, called jaundice, and problems with the central nervous system. Doctors often find visual problems caused by eye infection, as well as learning problems, and even mental retardation in these children months to several years later.
What are the causes and risks of the infection? The parasite, Toxoplasma gondii, is the cause of toxoplasmosis.
People can acquire toxoplasmosis by eating poorly cooked or raw meat and by caring for cats infected with the parasite.
What can be done to prevent the infection? To prevent this disease:
Eat only thoroughly cooked meats.
Wear gloves when gardening.
Change cat litter boxes daily and wash hands immediately afterwards.
People with HIV who have been infected with T. gondii in the past may need to take antibiotics to prevent toxoplasmosis from recurring.
How is the infection diagnosed? Doctors use a blood test that looks for antibodies to the parasite to diagnose this disease.
What are the long-term effects of the infection? A foetus that acquires toxoplasmosis can go on to have serious problems, including mental retardation, after birth. Toxoplasmosis can be fatal in people with damaged immune systems.
What are the risks to others? A woman who develops toxoplasmosis while she is pregnant can spread it to her foetus, but this is rare in Australia.
What are the treatments for the infection? Medications used to treat toxoplasmosis in an innumnosuppressed person include: pyrimethamine and sulfadiazine or clindamycin. Spiramycin is used to treat a pregnant woman with toxoplasmosis.
What are the side effects of the treatments? Serious problems are rare. Sometimes use of the drug results in abnormalities in blood cells and/or in a folic acid deficiency.
Author: Danielle Zerr, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 9/1/2005 Contributors Potential conflict of interest information for reviewers available on request
