Encyclopedia / T / Toxoplasmosis



Toxoplasmosis is an infection caused by a parasite called Toxoplasma gondii.


The parasite Toxoplasma gondii multiplies in the intestine of the cat and is shed in cat feces, mainly into litter boxes and garden soil.

Healthy adults usually do not suffer ill effects from Toxoplasma infection and may be asymptomatic. However, if you become infected while pregnant, your unborn child may also become infected. Infected babies may not develop any disease, or they may become very ill, with serious damage to the brain and eyes.

If you have been infected previously with Toxoplasma, you will generally develop immunity to it. An exception is immunocompromised persons (e.g. those with AIDS). The infection will not be active when you become pregnant, and so it will not pose a risk to your baby. Blood testing for detecting past or recent exposure to this parasite is available, but it is not routinely done.


Human infection results from ingestion of the parasites cysts in raw or undercooked meat, ingestion of oocysts on contaminated vegetables or other foods, following careless handling of cat litter, or from soil by soil-eating children. It can also be transmitted during pregnancy via the placenta.


Primary infection in immunocompetent people causes an acute, mild illness that may resemble infectious mononucleosis. Congenital infection only occurs as a result of infection in a non-immune woman during pregnancy.

Infection has been detected in up to 1 percent of women during pregnancy. About 15 to 60 percent of such infections are transmitted to the fetus, but only a small percentage result in abortion or stillbirths or in active disease. Fetal infection is more severe early in pregnancy.

Reactivated toxoplasmosis occurs in the immunocompromised host (AIDS, cancer, chemotherapy). The infection may present in specific organs or as a systemic (body-wide) disease.


Diagnosis relies on blood tests which detect antibodies to toxoplasma (indicating recent or past infection).

Sometimes, diagnosis is made from analysis of infected tissue (blood, bone marrow, sputum, etc.).


The immunocompetent, nonpregnant individual over 5 years of age with acute toxoplasmosis is treated with specific medications only if signs and symptoms are severe or persistent.

Immunocompromised patients must be treated, often for 4 to 6 weeks after cessation of symptoms.

During pregnancy, because early treatment reduces (but does not eliminate) the incidence of fetal infection, most physicians believe that treatment is justified. Congenitally-infected newborns are treated aggressively.

Medications for immunocompetent adults include pyrimethamine plus either trisulfapyrimidines or sulfadiazine. In pregnancy, spiramycin is usually given.


Is there a test that can be done on the cat to see if they have the parasite?

Will the cat show signs of having the toxoplasma gondii parasite? What are the signs/symptoms?

Is it treatable?

If a cat is in the house should pregnant woman be tested automatically?

What precautions should a pregnant woman take?

(Male) Can a husband infect his pregnant wife if toxoplasmosis has been diagnosed?

How does the medication regiment affect the development of the baby?

Will the baby be immune to toxoplasmosis?

Can other children (if applicable) get toxoplasmosis?

How to avoid toxoplasma during pregnancy:

  • Make sure your physician checks your blood for toxoplasma antibodies (depending on results, this may need to be repeated several times during your pregnancy).
  • Do not allow your cat to go outside your home where it may come into contact with Toxoplasma. If possible, have someone else take care of your cat while you are pregnant.
  • Have another family member change the cat litter box and then disinfect it with boiling water for five minutes.
  • If you must handle the chore of changing the litter box, wear rubber gloves to avoid contact with the litter and wash your hands thoroughly afterwards.
  • Use work gloves when gardening and wash your hands afterwards.
  • Cover children's sandboxes when not in use (cats like to defecate there).
  • Control flies and cockroaches as much as possible. They can spread contaminated soil or cat feces onto food.
  • Avoid eating raw or undercooked meat (or poultry) and unwashed fruits and vegetables.
  • Wash your hands thoroughly before you eat and after handling raw meat, soil, sand or cats.
  • Avoid rubbing your eyes or face when preparing food, and wipe the counter clean afterwards.
  • Avoid eating raw eggs and drinking unpasteurized milk.