Toxoplasmosis is an infection caused by a tiny organism called a protozoan. Many people are infected with this protozoan. However, few people have any symptoms or problems from it.
Toxoplasmosis is passed from animals to humans. People can contract it by:
A pregnant woman who gets toxoplasmosis for the first time may pass it to her unborn child. Active infection usually occurs once in a person’s life, although the protozoan remains inactive in the body. Generally, if a woman has become immune to the infection before getting pregnant, she will not pass the condition to her baby.
Factors that increase your chance of getting toxoplasmosis include:
Most people do not have symptoms. Those who do have symptoms may have:
People with weakened immune systems may have toxoplasmosis infections in multiple organs. Infection is most common in the brain ( encephalitis), eyes ( chorioretinitis), and lungs (pneumonitis). Symptoms may include:
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In babies, the severity of symptoms depends on when the mother became infected during pregnancy. If infection occurs during the first 3 months of pregnancy, babies are less likely to become infected. But if they do, then their symptoms are much more severe. During the last 6 months, babies are more likely to become infected. But, their symptoms are less serious. Toxoplasmosis can also cause miscarriage or stillbirth.
About one in 10 babies born with toxoplasmosis has severe symptoms. These include:
Many babies infected with toxoplasmosis may seem healthy at birth. But they may develop problems months or years later. These include:
You will be asked about your symptoms and medical history. A physical exam will be done. Blood tests are done to look for antibodies produced by the body to fight the toxoplasmosis. Other lab tests are done to look for the protozoa itself.
People who are healthy and not pregnant do not need treatment if symptoms are mild. Symptoms usually go away within a few weeks to months. People with a weakened immune system are treated with antitoxoplasmosis medications for several months.
If a pregnant woman is infected but the fetus is not, the mother is usually given an antibiotic. It can decrease the chance of the fetus becoming infected.
Fetuses with confirmed toxoplasmosis infections are treated by giving the mother a combination of these medications:
These medications can reduce the severity of, but not eliminate, a newborn's symptoms. After the baby is born, different combinations of medication will be given.
Women who are pregnant or considering becoming pregnant should talk to their physician about taking a blood test. It will help determine if they are immune to toxoplasmosis, which would be a sign of a prior exposure. If they are not, they should take the following steps to avoid sources of toxoplasmosis:
These steps also apply to people with weakened immune systems.
Centers for Disease Control and Prevention
Kids Health—Nemours Foundation
Women's Health Matters
ACOG practice bulletin. Perinatal viral and parasitic infections. Number 20, September 2000. Int J Gynaecol Obstet. 2002 Jan;76(1):95-107.
Parasites—toxoplasmosis (toxoplasma infection). Centers for Disease Control and Prevention website. Available at:
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Updated March 1, 2017. Accessed December 21, 2017.
Toxoplasmosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114869/Toxoplasmosis . Updated April 27, 2017. Accessed December 21, 2017.
Toxoplasmosis. Kids Health—Nemours Foundation website. Available at:
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Updated August 2014. Accessed December 21, 2017.
Last reviewed November 2018 by
EBSCO Medical Review Board
Kari Kassir, MD
Last Updated: 12/20/2014