Toxoplasmosis is caused by an infection by the parasite T. gondii. Humans get toxoplasmosis after accidentally eating (ingesting) something contaminated with the parasite.
Because of the way the parasite hides in your body, you can have symptoms of toxoplasmosis when you’re initially infected or at a later time. When the parasite initially enters your body, some people get flu-like symptoms. But in most cases, your immune system can get rid of the initial infection without causing any symptoms.
While your immune cells are fighting it off, T. gondii makes small sacs (cysts) in your body. It can live in these cysts, inactive (dormant), for long periods of time. Research suggests that the cysts break open periodically and your body fights off the infection. Like the initial infection, this usually causes no symptoms.
If your immune system is weakened, though, these ruptured cysts can cause a new case of toxoplasmosis (reactivation).
You typically get toxoplasmosis from ingesting something contaminated with the parasite T. gondii.
T. gondii reproduces in a cat’s intestines and ends up in their poop. Cat poop can contaminate soil, water, plant material and the food we eat.
You can accidentally ingest T. gondii after coming in contact with something that’s contaminated, such as:
Toxoplasmosis isn’t contagious. But if you're pregnant, you can pass the parasite that causes it to the fetus. You can also get toxoplasmosis after receiving an infected organ transplant or blood transfusion, though this is rare.
The symptoms of toxoplasmosis depend on where the parasite is active. This tends to be different depending on whether it’s a new (acute) infection, a reactivation or present at birth (congenital).
Ocular toxoplasmosis is an infection of T. gondii in one or both eyes. It’s most common in teens or young adults who were born with a T. gondii infection. Rarely, ocular toxoplasmosis happens when you’re first infected with T. gondii. Symptoms of ocular toxoplasmosis include:
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Acute toxoplasmosis is your body’s response to an initial infection with T. gondii. Most people don’t feel sick, but you might have flu-like symptoms, including:
If you have a weakened immune system (immunocompromised), you might have had a previous T. gondii infection that reactivates when your body is no longer able to fight off infections easily. This includes people living with AIDS or cancer, or those on medications that suppress the immune system. Reactivated toxoplasmosis usually causes symptoms related your brain and spinal cord (central nervous system or CNS). CNS symptoms can include:
Congenital (present at birth) toxoplasmosis is passed through the placenta to the fetus. Some babies won’t have any symptoms at birth, but are at high risk for developing them later on. These symptoms may include:
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To diagnose toxoplasmosis, your healthcare provider will perform a physical exam and ask you about your symptoms. They may order blood tests, biopsies, imaging (CT scan or MRI), a lumbar puncture or, if you’re pregnant, amniocentesis or ultrasound.
To diagnose toxoplasmosis, your healthcare provider may order some or all of these tests:
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Toxoplasmosis is treated with a combination of anti-parasitic medicines and antibiotics. These stop T. gondii from growing and reproducing in your body.
Folinic acid is given during toxoplasmosis treatment to reduce the side effects of the anti-parasitic medications.
Toxoplasmosis isn’t usually treated in people who don’t have a compromised immune system and don’t have any symptoms. Treatment for toxoplasmosis can only work when parasites are active. It can’t get rid of the cysts the parasites leave in your body.
These medications are typically used to treat toxoplasmosis:
Most treatment plans for toxoplasmosis last two to six weeks, but you may start to feel better in only a few days. It may take three weeks to six months for brain injuries caused by the parasite to fully resolve.
Even if you feel better, you may have to stay on treatment for a long time to make sure the active parasites have been destroyed. If you’re pregnant and have been diagnosed with toxoplasmosis, you’ll probably have to take medication for the rest of the pregnancy. Treatment for congenital toxoplasmosis can last up to a year. Treatment in those with weakened immune systems can be given indefinitely.
If you’re pregnant and have been diagnosed with toxoplasmosis, follow your healthcare provider’s recommendation to reduce the risk of passing it to the fetus.
If you have a weakened immune system and have been diagnosed with toxoplasmosis, you and your healthcare provider can make a plan for treating toxoplasmosis while managing any other underlying conditions.
The outlook for toxoplasmosis varies. People with healthy immune systems rarely develop serious complications from toxoplasmosis.
In congenital toxoplasmosis, more than 70% of children will reach developmental milestones as expected with prompt treatment.
In patients with a weakened immune system, toxoplasmosis is most often found in the brain. With treatment, survival rates are at least 70%. Without treatment, toxoplasmosis of the brain is fatal.
Because of the cysts left behind by T. gondii, toxoplasmosis may never be fully cured. Medication can treat an active infection, but it doesn’t destroy the cysts.
If you have a healthy immune system, the cysts shouldn’t reactivate. But if you have a weakened immune system or if you have congenital toxoplasmosis, the parasite can reactivate and make you sick in the future.
Safe food preparation and hand washing are the most important things you can do to help prevent toxoplasmosis.
If you’re pregnant or have a compromised immune system:
If you’ve been diagnosed with toxoplasmosis, keep an eye on your symptoms. Whether you’ve been prescribed treatment or not, call your healthcare provider if they don’t improve or get worse.
If your child was diagnosed with toxoplasmosis at birth, work closely with their pediatrician to make sure they get appropriate treatment. Follow up even after treatment is done on their provider’s recommended schedule. Know what signs of reactivation to look for.
If you’re pregnant or plan to become pregnant or if you have a compromised immune system, you should talk to your healthcare provider about steps you can take to prevent toxoplasmosis in yourself or your future child.
If you have symptoms of toxoplasmosis, especially if you have a compromised immune system, contact your provider right away.
Like humans, cats often don’t show any symptoms of toxoplasmosis. Ask your veterinarian if you have questions about toxoplasmosis in your pet cat.
Since there are usually no symptoms, it’s difficult to determine what percentage of cat owners have toxoplasmosis. However, research suggests that cat ownership itself doesn’t put you at significantly higher risk than others.
No, you don’t necessarily have to get rid of your cat if you’re pregnant or have a weakened immune system. Cat lovers can take precautions to reduce the risk of toxoplasmosis.
Keeping your cat indoors, having someone else change the litterbox frequently and not feeding your cat raw or undercooked meat all reduce the risk of you and your cat getting toxoplasmosis. If you do have to change the litterbox, wear gloves and a mask and wash your hands immediately after.
Finally, don’t take in stray cats or adopt a new cat while you’re pregnant or have a weakened immune system.
Toxoplasmosis isn’t typically a serious illness, but it’s a unique threat during pregnancy and to those with compromised immune systems. Fortunately, there are many ways to help prevent an infection. Talk to your healthcare provider about how to reduce your risk of toxoplasmosis based on your specific circumstances.
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Last reviewed on 08/02/2022.
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