Toxoplasmosis is an infection caused by a tiny organism called a protozoon. Many people are infected with this protozoon. However, few people have any symptoms or problems from it.



Toxoplasmosis is passed from animals to humans. People can contract it by:

  • Touching infected cat feces or something that has had contact with cat feces, such as soil or insects
  • Eating undercooked, infected meat, or by touching your mouth after touching the meat
  • In rare cases, receiving a blood transfusion or an organ transplant

A pregnant woman who gets toxoplasmosis for the first time may pass it to her unborn child. Active infection usually occurs one time in a person’s life, although the protozoon 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.


Risk Factors  

Factors that increase your chance of getting toxoplasmosis include:

  • Babies born to mothers who are first exposed to toxoplasmosis just before becoming pregnant or during pregnancy
  • People with weak immune systems from causes such as:
Swollen brain

Copyright © Nucleus Medical Media, Inc.


Most people do not have symptoms. Those who do have symptoms may have:

  • Swollen lymph nodes
  • Fever
  • Fatigue
  • Sore throat
  • Muscle aches and pains
  • Rash

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:

  • Fever
  • Seizures
  • Headache
  • Visual defects
  • Problems with speech, movement, or thinking
  • Mental illness
  • Shortness of breath

In babies, the severity of symptoms depends on when the mother became infected during pregnancy. If infection occurs during the first three months of pregnancy, babies are less likely to become infected. But if they do, then their symptoms are much more severe. During the last six 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:



The doctor will ask about symptoms and medical history.