Toxoplasmosis is a disease caused by the Toxoplasma gondii parasite. In the U.S., research suggests around 11% of people over six years old have had the infection. In hot, humid parts of the world with lower elevations, as much as 60% of the population might get it at some point. People with healthy immune systems usually don’t have any symptoms from or complications of this infection.

How Toxoplasmosis is Contracted

A person cannot get toxoplasmosis from another person. Instead, the parasite is spread through contact with infected cat feces and eating, drinking, or washing with contaminated foods and water. In a few very rare instances, people contract toxoplasmosis from an organ transplant or blood transfusion.

Symptoms of Toxoplasmosis in Healthy People

Healthy people will not usually experience symptoms of toxoplasmosis, and the body is capable of dealing with the infection. If signs do develop, a healthy person might experience flu-like symptoms, such as a headache and fatigue, and possibly fever and swollen lymph nodes.

Symptoms of Toxoplasmosis in People with Compromised Immune Systems

Toxoplasmosis is more dangerous for people with weak or compromised immune systems. Signs and symptoms of serious infection can develop in these individuals, including

• Poor coordination
• Headache
• Seizures
• Lung problems similar to tuberculosis
• Blurry vision if the retina becomes inflamed

Toxoplasmosis and Pregnancy

If a pregnant woman is infected with the parasite, she can pass the infection to her fetus. This is most common if the infection happens during the woman’s third trimester. However, if the infection does transfer earlier, it can mean more serious complications. A baby born with toxoplasmosis can develop seizures and have an enlarged liver and spleen and jaundice. Most infants born with the infection don’t show symptoms right away. As they get older, signs such as hearing loss or mental disabilities can develop.

Risk Factors for More Serious Infections

While anyone exposed to infected feces or contaminated food or water might contract toxoplasmosis, the people most at risk for serious repercussions are those with conditions that weaken the immune system, such as HIV/AIDS. People getting chemotherapy or taking other immunosuppressant drugs also face a higher risk of dangerous symptoms. Complications in People with Compromised ImmunityA person with a compromised immune system could develop encephalitis, a severe brain infection that, untreated, can lead to death. In rare cases, otherwise healthy people with toxoplasmosis develop eye infections that can cause blindness if they are not treated.

Getting Tested

People at higher risk of serious illness from the toxoplasma gondii parasite can take a blood test. Women trying to become pregnant might receive this test from their doctor, and women who are already expecting can also be tested. People with weakened immune systems who test positive for toxoplasmosis might be prescribed medications that will help prevent the infection from reactivating.

Toxoplasmosis Treatments

If a blood test on a healthy person without symptoms shows toxoplasmosis, it is unlikely a doctor will prescribe any treatment — the immune system should be able to get rid of the infection on its own, and any symptoms should resolve in a few weeks or months. People at risk for complications from toxoplasmosis can take medications to treat the infection.

Preventing Toxoplasmosis

Safe food handling and avoiding potentially unsafe water sources is the best way to prevent toxoplasmosis infections. Freezing meat for a few days before cooking will usually kill off the parasite, as will cooking meat to the recommended internal temperatures. Cleaning your cat’s litter box daily is a good way to prevent infections because the parasite does not become infectious until one to five days after it is excreted. Always wash your hands well after handling cat litter.

More Details for Cat Owners

Keeping your cat indoors and feeding it pet food instead of raw meat is one good way to prevent toxoplasma gondii at the source. If you are at risk for toxoplasmosis complications or are trying to become pregnant, it is best to let someone else clean the litter box. Do not play with or adopt stray cats, as they are more likely to carry the parasite.