About Toxoplasmosis

Key points

  • Toxoplasmosis is an infection caused by a parasite.
  • A parasite is an organism (a living thing) that lives on or inside another organism.
  • Most people with healthy immune systems do not have symptoms if infected.
  • You can take steps to prevent toxoplasmosis infection.


Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. It is the leading cause of death from foodborne illness in the United States.

  • The parasite occurs worldwide and can last for long periods of time (up to a lifetime) in human bodies (and other animals).
  • People who are pregnant or people who are immunocompromised (have a weakened immune system) can take steps to reduce their risk of infection due to Toxoplasma infection causing more serious health problems.

Signs and symptoms

Over 40 million people are infected with the parasite in the United States. Most people with healthy immune systems who get toxoplasmosis do not have symptoms. Those with symptoms may experience flu-like symptoms, swollen lymph nodes, muscle aches, and pains.

  • Severe toxoplasmosis causes damage to the brain, eyes, or other organs.

Ocular (eye) toxoplasmosis can cause damage to the eye. An ophthalmologist treats this type of toxoplasmosis.

Infants infected while still in the womb often have no symptoms at birth but can develop symptoms later in life.

People at risk

Although anyone can become infected with toxoplasmosis, some people need to be more cautious given their health condition, including

  • People who are pregnant
  • People who are immunocompromised (have a weakened immune system)

People who are at risk for developing severe toxoplasmosis include

  • Infants born to mothers who are newly infected with Toxoplasma gondii during or just before pregnancy
  • People who are severely immunocompromised, including those with HIV, those taking certain types of chemotherapy, and those who recently received an organ transplant


You can become infected with Toxoplasma through the following:

  • Foodborne transmission: eating contaminated undercooked meat or shellfish or unwashed contaminated fresh produce
  • Animal to human transmission: accidentally consuming the parasite through contact with cat feces (poop) or contaminated soil that contains Toxoplasma
  • Mother-to-child (congenital) transmission: when a newly infected mother passes the infection to their unborn child
  • Other modes of transmission: receiving an infected organ transplant or infected blood via transfusion (though this is rare)


Follow these steps to reduce your risk of becoming infected with Toxoplasma gondii:

Food precautions

  • Use a food thermometer to cook food to a safe internal temperature high enough to kill Toxoplasma.
  • Freeze meat* for several days at sub-zero (0° F) temperatures before cooking to greatly reduce chance of infection.
  • Rinse fruit and vegetables under running water or cook them.
  • Do not drink unpasteurized goat's milk.
  • Do not eat raw oysters, mussels, or clams.

*Cooking meat to recommended internal temperatures is the safest method.

Cleanliness practices

  • Clean areas where you handle food with hot, soapy water after preparing each food item.
  • Wear gloves when gardening or touching soil or sand that may be contaminated with cat feces containing Toxoplasma.
  • Wash hands with soap and water any time you touch something that may be contaminated with cat feces containing Toxoplasma.
  • If you have a cat, change the litter box daily.

Talk to your healthcare provider about additional precautions if you are a person at risk for severe infection.


If you think you may have toxoplasmosis, talk to your healthcare provider. They may order different blood tests to help determine if you are infected.

Treatment and recovery

Most people with healthy immune systems do not need treatment. If symptoms occur, they will usually go away within a few weeks to months. If needed, healthcare providers can prescribe treatment.

Animal transmission

Cats play a key role in the spread of toxoplasmosis. Talk to your veterinarian if you have additional questions about your cats and their risk.

Learn more about toxoplasmosis and cats.