Most infected people have no symptoms and are never diagnosed. People with weakened immune systems can develop severe toxoplasmosis, which results in damage to the eye or the brain. Infants who are infected before birth can have serious mental or physical handicaps. Most people do not need to be treated unless they are pregnant or have a weakened immune system. Pregnant women, women who are planning to become pregnant, and persons with weakened immune systems should take precautions to avoid infection.
Toxoplasmosis is a common parasitic infection worldwide.
People at risk for severe infection are pregnant women and persons with weakened immune systems. Toxoplasmosis is caused by Toxoplasma gondii , a one-celled parasite. The parasite that causes toxoplasmosis is found worldwide. In these people, an infection that occurred anytime during life can reactivate and cause the severe symptoms of toxoplasmosis. For about 2 weeks after infection with Toxoplasma , cats pass millions of parasites in their stool every day.