How Do You Get Toxoplasmosis? Tips

Toxoplasmosis is an infection caused by the Toxoplasma gondii parasite. You get it by accidentally swallowing the parasite. This happens most often by eating undercooked meat, especially pork and lamb, or by handling cat feces that contain the parasite. Tips to prevent infection include cooking meat to safe temperatures, washing fruits and vegetables, wearing gloves while gardening, and avoiding cleaning cat litter boxes if you are pregnant or have a weakened immune system.

How Do You Get Toxoplasmosis?

The parasite Toxoplasma gondii only reproduces inside cats. But it can infect almost any warm-blooded animal, including humans. You get toxoplasmosis when you accidentally swallow the parasite in its infectious form, called an oocyst or tissue cyst.

The most common ways this happens are:

• Eating undercooked, infected meat. Pork, lamb, and venison are the most common sources. The parasite forms cysts in muscle tissue. If meat is not cooked to a high enough internal temperature, those cysts stay alive and can infect you.
• Contact with cat feces. Cats shed millions of oocysts in their stool for one to three weeks after they first become infected. You can pick up these oocysts by cleaning a litter box, touching contaminated soil, or accidentally ingesting them.
• Drinking contaminated water. In some parts of the world, water sources have been contaminated by cat feces or runoff from infected animals. Outbreaks linked to municipal water systems have been reported.
• Eating unwashed produce. Fruits and vegetables grown in soil contaminated with cat feces can carry oocysts on their surface.
• From mother to baby during pregnancy. If a woman catches toxoplasmosis for the first time while pregnant, the parasite can cross the placenta and infect the fetus. This is called congenital toxoplasmosis.

You cannot get toxoplasmosis from directly touching an infected person. Casual contact, kissing, or sharing utensils does not spread the parasite.

What Is Toxoplasmosis and Who Is at Risk?

Toxoplasmosis is a parasitic infection. Most people who get it never know they have it. The immune system usually controls the parasite quickly, and the infection becomes dormant. Cysts remain in the body, often in the brain and muscle, for life without causing problems.

Serious illness happens almost exclusively in two groups:

• Pregnant women who get infected for the first time. The risk to the baby depends on when during pregnancy the infection occurs. Infections in early pregnancy are less likely to pass to the baby but can cause more severe damage if they do. Infections later in pregnancy are more likely to pass to the baby, but the baby is often born without symptoms at first.
• People with weakened immune systems. This includes people on chemotherapy, organ transplant recipients, those with HIV/AIDS not on treatment, and people taking high-dose steroids or other immunosuppressive medications. In these individuals, a dormant infection can reactivate and cause severe disease, especially in the brain.

Eye disease from toxoplasmosis can occur in anyone, even people with healthy immune systems. It usually happens when a dormant cyst reactivates in the retina.

What Are the Symptoms of Toxoplasmosis?

Most people have no symptoms at all. When symptoms do occur, they are usually mild and flu-like. They include:

• Low-grade fever
• Swollen lymph nodes, especially in the neck
• Muscle aches
• Fatigue
• Headache

These symptoms typically resolve on their own within a few weeks. Because they look like the common cold or flu, many cases are never diagnosed.

In people with weakened immune systems, symptoms can be much more serious. The parasite most often attacks the brain, causing confusion, seizures, headache, and coordination problems. It can also cause pneumonia or inflammation of the heart muscle.

Congenital toxoplasmosis may cause no symptoms at birth, but some babies are born with eye damage, hearing loss, or developmental delays. Symptoms can also appear months or years later.

How Can You Prevent Toxoplasmosis? Tips

Prevention is straightforward because the parasite enters the body through the mouth. Cut off the route of entry, and you cut off infection. Here are evidence-based tips:

• Cook meat thoroughly. The Toxoplasma cysts in meat are killed when the internal temperature reaches 145°F for whole cuts of meat (followed by a three-minute rest) and 160°F for ground meat. Poultry should reach 165°F. Use a food thermometer.
• Freeze meat for long periods. Freezing at 0°F for several days can kill many cysts, but it is less reliable than cooking. Freezing does not guarantee safety in all cases.
• Wash fruits and vegetables thoroughly. Running water and gentle scrubbing removes oocysts from the surface. Peeling is even more effective.
• Wear gloves when gardening. Cats use soil as a litter box. Assume soil may contain oocysts. Wash hands immediately after gardening.
• Change cat litter daily or have someone else do it. Oocysts need at least 24 hours to become infectious. If you scoop the litter box every day, you remove them before they can cause infection. If you are pregnant or immunocompromised, avoid handling litter entirely.
• Keep cats indoors. Outdoor cats are more likely to catch and eat infected birds or rodents, which makes them shed oocysts. Indoor cats that never hunt are unlikely to be infected.
• Do not feed your cat raw meat. Raw or undercooked meat in cat food increases the chance your cat becomes infected and sheds oocysts.
• Practice good hand hygiene. Wash hands after handling raw meat, after contact with soil, and after cleaning the litter box.

These tips are especially important for pregnant women and people with weakened immune systems. For the general population, the risk is very low, but following these practices is still sensible.

How Is Toxoplasmosis Diagnosed and Treated?

Diagnosis is usually done with a blood test that looks for antibodies against Toxoplasma gondii. A positive IgM test may indicate a recent or active infection, but the test is not perfectly reliable. IgG antibodies mean you were infected at some point in the past. In pregnant women, additional tests such as PCR on amniotic fluid can confirm if the fetus is infected.

Healthy people with mild symptoms generally do not need treatment. The immune system clears the active infection on its own. Treatment is reserved for specific groups:

• Pregnant women with a new infection (to reduce the risk of passing it to the baby)
• Infants with congenital toxoplasmosis
• People with weakened immune systems who have active disease
• People with eye disease that threatens vision

The standard treatment is a combination of pyrimethamine and sulfadiazine, along with folinic acid to protect the bone marrow. Treatment lasts weeks to months depending on the severity. Drug shortages and side effects can complicate therapy.

No medication can completely eliminate the dormant cysts. Once you are infected, the parasite stays with you. But for most people, that fact has no practical consequence.