Toxoplasmosis and Pregnancy
by: Michael Schmitt and Val Hillers
Dept. of Food Science and Human Nutrition
Washington State University
Are you pregnant or planning on becoming pregnant?
Then you should read about toxoplasmosis, a disease that is caused byToxoplasma gondii. If you were to become infected withToxoplasma gondii while pregnant, it could seriously
harm your unborn child.
Avoid the following because they are potential sources ofToxoplasma:
- Raw or undercooked meat.
- Unwashed, uncooked fruit and vegetables.
- Unpasteurized milk and unpasteurized dairy products.
- Fecally contaminated cat litter.
- Soil contaminated with cat feces.
What is toxoplasmosis?
Toxoplasmosis is a disease caused by a parasitic protozoa,Toxoplasma gondii, which is a single cell organism which lives in, and gets its nutrients, from other animals. It has a very complex life cycle, which involves the cat as the animal in which it carries out most of its life cycle.
Toxoplasma infect humans if they ingest the infectious forms of this parasite, called oocysts (from cat feces) or pseudocysts (in meat or unpasteurized milk).
Most outdoor cats become infected withToxoplasma soon after they are weaned by eating a wild bird or rodent that has been infected withToxoplasma. Indoor cats who eat only commercial cat food are unlikely to become infected withToxoplasma.
Cats shed oocysts in their feces for only a few weeks after the time of initial infection. Once the oocyst is shed by the cat, it takes several days for the oocyst to become infectious.
Oocysts can survive in soil and water for many months and can be found in gardens, playgrounds, barns, stables, or anywhere else that cats roam. Oocysts slowly die at below-freezing temperatures. The oocysts are easily moved from location to location by wind, water, birds, insects, the feet
of humans and animals, garden tools, and outdoor machinery.
Toxoplasma also can infect some food animals including pigs, sheep, goats, and cows. Raw or undercooked meat or unpasteurized milk from infected animals may contain pseudocysts, which are infectious for humans. One research study suggests that undercooked ground pork is a primary risk factor for toxoplasmosis.
What are the symptoms of toxoplasmosis?
When adults are infected, they frequently have few, if any, symptoms. Although the symptoms for adults are usually mild, children who get the disease frequently experience more serious illness.
Signs of infection consist of muscle aches and pain, headache, fever with rash, and swelling of the lymph nodes. Toxoplasmosis can sometimes be misdiagnosed as the flu (influenza) or infectious mononucleosis. Treatment for toxoplasmosis is possible through medications.
Up to half of Americans are thought to have been infected withToxoplasma gondii at some time during their life. Once infected, people are usually immune to further infections withToxoplasma gondii. During the active infection, the cysts travel from the intestine to other parts of the body where they are "walled off" and the body's immune system develops antibodies which prevent the cysts in the tissue from causing additional illness. The antibodies in the blood also prevent re-infection if the person is exposed to another source ofToxoplasma in food or soil. An exception is that immunocompromised individuals (those on chemotherapy or with AIDS
for example) may show signs of toxoplasmosis more than once.
Toxoplasmosis has added risks during pregnancy
Women who are infected withToxoplasma while pregnant may have few symptoms and yet may pass the disease on to their unborn child. If a developing child (fetus) gets infected withToxoplasma, consequences may be severe including brain damage from hydrocephalus, epilepsy,
and vision problems. Miscarriage of the fetus may result.
The actual number of cases of congenital toxoplasmosis cases in the U.S.
is not known, but it is estimated to range from 400 to 9,500 cases per year.
About 2% of the time when a pregnant woman is infected with toxoplasmosis,
the fetus dies.
If a pregnant woman who has been previously infected withToxoplasma
is immunocompromised (such as with AIDS), there is a risk that she will
have a recurrence of symptoms of toxoplasmosis during her pregnancy. During
the periods that symptoms of toxoplasmosis reappear, the disease may be
passed on to the fetus. It is possible to be tested for infection byToxoplasma
gondii through a check for specific antibodies. If you have an antibody
titer, it means that you have already been infected with toxoplasma and
you are not likely to be reinfected.
How can you prevent getting toxoplasmosis during pregnancy?
Any actions taken to reduce contamination of the environment with oocysts from cat feces will reduce the risk of you getting toxoplasmosis.
- Thoroughly cook meats (140įF for at least 4 minutes). As an added
precaution, freeze ground pork for several weeks before eating or avoid
eating ground pork during pregnancy.
- Wash everything thoroughly (knives, cutting boards and hands) that
comes in contact with raw meat.
- Wash fruits and vegetables thoroughly.
- Do not use unpasteurized milk or unpasteurized dairy products.
- If you own a cat, wear gloves while cleaning the litter box, or preferably, have someone else clean it for you. Clean the litter box each day since oocysts need 2 days in the air after being shed by the cat in order to become infectious.
- Wear gloves while gardening to prevent soil from getting on your hands.
- Wash your hands before eating.
A final word...
As an expectant mother, it may be easy to become anxious about the health of your child. This brochure is designed to inform you of the possibility of getting toxoplasmosis and how to prevent yourself from getting the disease. However, please be reassured that you donít need to make huge changes in your daily life to protect your child. Follow the above guidelines, and you will greatly reduce the risk of getting this disease for both you and your child.