Toxoplasmosis

Toxoplasmosis is an illness you can get from contact with contaminated cat poop or by eating undercooked meat. The parasite Toxoplasma gondii (T. gondii) causes it.

Most people don’t have symptoms when they first get toxoplasmosis (“tok-soh-plaz-MOH-sis”). Your body usually fights off the parasite without you knowing it was there. About 10% to 20% of people have mild symptoms that resolve on their own.

But the parasite can remain in your body as cysts, which can reactivate later. This can cause serious complications if you have a compromised immune system.

If you get toxoplasmosis while pregnant, it can cause pregnancy loss or serious health problems for your child. Toxoplasmosis is why certain people should avoid cleaning cats’ litter boxes.

Types

Types of toxoplasmosis include:

• Ocular toxoplasmosis: 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.
• Reactivated toxoplasmosis: If you have a weakened immune system, a previous T. gondii infection can reactivate. HIV, cancer and certain medications can weaken your immune system.
• Congenital toxoplasmosis: Congenital (present at birth) toxoplasmosis passes through the placenta to the fetus during pregnancy. Some babies won’t have any symptoms at birth. But they’re at high risk for developing them in childhood.

Symptoms of toxoplasmosis

The symptoms of toxoplasmosis depend on the type. Most people don’t have symptoms when first infected. But you might have flu-like symptoms, including:

• Fever
• Fatigue
• Muscle aches
• Painless, swollen lymph nodes in your neck or armpits
• Sore throat
• Eye pain, blurred vision or vision loss (rare)

These usually resolve on their own in several weeks.

If a previous infection reactivates, symptoms could include:

• Headaches
• Confusion
• Seizures
• Fever
• Facial paralysis
• Vision changes
• Numbness
• Weakness or loss of motor skills (things that require muscle movement, like walking or picking objects up)

Congenital toxoplasmosis symptoms

Some signs and symptoms of congenital toxoplasmosis are present at birth. Some develop later in childhood. They could include:

• Yellowish skin and eyes (jaundice)
• Rash
• Enlarged liver and spleen (hepatosplenomegaly)
• Vision loss, eye pain or sensitivity to light (retinochoroiditis)
• Calcium deposits in the brain
• Fluid on the brain (hydrocephalus)
• Small head size (microcephaly)
• Seizures
• Delays in motor skill development
• Learning delays or differences
• Eye pain, blurred vision or blindness (ocular toxoplasmosis)

Toxoplasmosis causes

The parasite T. gondii causes toxoplasmosis. T. gondii reproduces in a cat’s intestines and ends up in its poop. Humans get toxoplasmosis after accidentally eating (ingesting) something contaminated with poop. It might be hard to imagine this happening. But it can happen if you eat undercooked meat, clean litter boxes or garden.

Because of the way the parasite forms cysts in your body, it can make you sick in various ways. 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).

How do you get toxoplasmosis?

You usually get toxoplasmosis from ingesting something contaminated with cat poop that contains the parasite. 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. For example:

• Cleaning a cat’s litter box
• Gardening in soil where cats live
• Drinking water that hasn’t been boiled or treated
• Eating unwashed fruits or vegetables
• Eating undercooked or improperly refrigerated meat

Toxoplasmosis isn’t contagious. But if you’re pregnant, the fetus can get infected with the parasite. Rarely, you can get toxoplasmosis after receiving an infected organ transplant or blood transfusion.

Risk factors

Toxoplasmosis is most dangerous if you’re pregnant or have a weakened immune system. Even though T. gondii reproduces in cats, having a cat on its own doesn’t seem to increase your risk of infection very much.

If you’ve had toxoplasmosis in the past, T. gondii lives in cysts in your body. When your immune system is weakened, it can reactivate and make you sick.

If you get toxoplasmosis during pregnancy or shortly before getting pregnant, you can pass the parasite through the placenta to the fetus. This increases the risk of pregnancy loss or serious health problems for your child.

Complications

You’re at a higher risk for complications from toxoplasmosis if you have a weakened immune system. Some complications can be fatal. Complications include:

• Enlarged liver and spleen
• Inflammation of your brain (encephalitis) or the lining around your brain and spinal cord (meningitis)
• Inflammation of your heart muscle (myocarditis) or the sac around your heart (pericarditis)
• Pneumonia
• Respiratory failure
• Organ damage

Infections during pregnancy can cause miscarriage or stillbirth. Complications of being born with toxoplasmosis include:

• Vision issues
• Blindness
• Developmental delays
• Learning differences

How doctors diagnose toxoplasmosis

To diagnose toxoplasmosis, your healthcare provider will examine you and ask about your symptoms. They may recommend:

• Blood tests: Blood tests are almost always performed to diagnose toxoplasmosis. Your provider sends a sample of your blood to a lab to look for antibodies to T. gondii. They may also look for parts of the parasite (DNA).
• Biopsy: Rarely, your healthcare provider may take a small amount of tissue and send it to a lab to look for signs of T. gondii.

If you have symptoms of toxoplasmosis in your brain, your provider may recommend:

• Imaging: A CT scan or MRI can show signs of infection in your brain or spinal cord.
• Lumbar puncture: A lab will look for signs of T. gondii in a sample of cerebrospinal fluid (CSF).

If you’re pregnant and have toxoplasmosis, your provider may recommend:

• Amniocentesis: Your pregnancy care provider will send a sample of amniotic fluid to a lab to look for signs of T. gondii.
• Ultrasound: This can’t diagnose toxoplasmosis on its own. But it can show changes to the fetus’s brain from an infection.

How is toxoplasmosis treated?

Healthcare providers treat toxoplasmosis with a combination of antiparasitic medicines and antibiotics. These stop T. gondii from growing and reproducing in your body. You also might get folinic acid to reduce the side effects of the antiparasitic medications.

Treatment only works when parasites are active. It can’t get rid of the cysts they leave in your body. You might not need treatment if you don’t have a compromised immune system and don’t have any symptoms.

Specific medications

Common medications that treat toxoplasmosis include:

• Pyrimethamine
• Sulfadiazine
• Atovaquone
• Spiramycin (before 18 weeks of pregnancy)
• Trimethoprim-sulfamethoxazole
• Clindamycin
• Leucovorin

Recovery time

Treatment can 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 symptoms of brain injuries to fully resolve. Some symptoms may be permanent.

Even if you feel better, you may have to stay on treatment for a long time to make sure the active parasites are destroyed. If you have a weakened immune system, there’s no set timeframe for how long you’ll need to take antiparasitic medications.

If you’re pregnant and have toxoplasmosis, you’ll probably have to take medication for the rest of the pregnancy. Treatment for congenital toxoplasmosis can last up to a year.

When should I see my healthcare provider?

Talk to your healthcare provider about steps you can take to prevent toxoplasmosis if you:

• Are pregnant
• Plan to become pregnant
• Have a compromised immune system

If you have symptoms of toxoplasmosis, especially if you have a compromised immune system, contact your provider right away.

What is the outlook for toxoplasmosis?

The outlook for toxoplasmosis varies. Most people don’t develop serious complications. But if you have a weakened immune system, toxoplasmosis could cause serious health issues, including brain inflammation. Without treatment, it can be fatal.

Babies born with toxoplasmosis are less likely to develop complications later in childhood if diagnosed and treated early.

Does it ever go away?

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. Some damage the infection causes can be permanent.

If you have a weakened immune system or congenital toxoplasmosis, the parasite can reactivate and make you sick in the future.

Can toxoplasmosis be prevented?

Safe food preparation and handwashing are the most important things you can do to help prevent toxoplasmosis:

• Follow safe freezing and cooking practices before eating meat.
• Peel fruits and vegetables or wash them thoroughly before eating.
• Wash cutting boards, counters, utensils and dishes with soapy water after use.
• Don’t drink unpasteurized milk or untreated water.
• Don’t eat raw or undercooked clams, oysters or mussels.
• Wear gloves when gardening and while working with soil or sand. Wash your hands with soap and water afterward.
• Cover outdoor sandboxes.
• Don’t feed cats raw or undercooked meat.
• Change cat litter daily. Wear gloves and wash your hands with soap and water afterward.
• Keep cats indoors.

Here are some precautions to take if you’re pregnant or have a compromised immune system:

• Avoid changing cat litter yourself if possible.
• If you must change cat litter, wear disposable gloves and wash your hands thoroughly afterward.
• Don’t adopt a new cat or take in a stray cat.