What is toxoplasmosis?

Toxoplasmosis (tok-so-plaz-MOE-sis) is a disease that results from infection with the Toxoplasma gondii parasite, one of the world’s most common parasites. Infection usually occurs by eating undercooked contaminated meat, exposure from infected cat feces, or mother-to-child transmission during pregnancy.

Toxoplasmosis may cause flu-like symptoms in some people, but most people affected never develop signs and symptoms. For infants born to infected mothers and for people with weakened immune systems, toxoplasmosis may cause serious complications.

If you’re generally healthy, not pregnant, and have been diagnosed with toxoplasmosis, you probably won’t need any treatment other than conservative management. If you’re pregnant or have lowered immunity, you may need medical management to avoid severe complications. The best approach, though, is prevention.

How do people get toxoplasmosis?

A Toxoplasma infection occurs by one of the following:

▪️Eating undercooked, contaminated meat (especially pork, lamb, and venison) or shellfish (for example, oysters, clams or mussels).

▪️Accidental ingestion of undercooked, contaminated meat or shellfish after handling them and not washing hands thoroughly (Toxoplasma cannot be absorbed through intact skin).

▪️Eating food that was contaminated by knives, utensils, cutting boards and other foods that have had contact with raw, contaminated meat or shellfish.

▪️Drinking water contaminated with Toxoplasma gondii.

▪️Accidentally swallowing the parasite through contact with cat feces that contain Toxoplasma. This might happen byCleaning a cat’s litter box when the cat has shed Toxoplasma in its feces;Touching or ingesting anything that has come into contact with cat feces that contain Toxoplasma; orAccidentally ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden).

▪️Mother-to-child (congenital) transmission.

▪️Receiving an infected organ transplant or infected blood via transfusion, though this is rare.


Most healthy people who are infected with toxoplasmosis have no signs or symptoms and aren’t aware that they’re infected. Some people, however, develop signs and symptoms similar to those of the flu, including:

▪️Body aches.

▪️Swollen lymph nodes.




In people with weakened immune systems.

If you have HIV/AIDS, are receiving chemotherapy or have recently had an organ transplant, a previous toxoplasma infection may reactivate. In that case, you may develop more-severe signs and symptoms of infection, including:



▪️Poor coordination.


▪️Lung problems that may resemble tuberculosis or Pneumocystis jiroveci pneumonia, a common opportunistic infection that occurs in people with AIDS.

▪️Blurred vision caused by severe inflammation of your retina (ocular toxoplasmosis).

In babies.

If you become infected for the first time just before or during your pregnancy, you can pass the infection to your baby (congenital toxoplasmosis), even if you don’t have signs and symptoms yourself.

Your baby is most at risk of contracting toxoplasmosis if you become infected in the third trimester and least at risk if you become infected during the first trimester. On the other hand, the earlier in your pregnancy the infection occurs, the more serious the outcome for your baby.

Many early infections end in stillbirth or miscarriage. Infants who survive are likely to be born with serious problems, such as:


▪️An enlarged liver and spleen.

▪️Yellowing of the skin and whites of the eyes (jaundice).

▪️Severe eye infections.

Only a small number of babies who have toxoplasmosis show signs of the disease at birth. Often, infants who are infected don’t develop signs — which may include hearing loss, mental disability or serious eye infections — until their teens or later.

When to see a doctor.

If you are living with HIV or AIDS or are pregnant or thinking of becoming pregnant, talk to your doctor about being tested if you think you may have been exposed to toxoplasmosis.

The signs and symptoms of severe toxoplasmosis — blurred vision, confusion, loss of coordination — require immediate medical care, particularly if your immune system has been weakened.


Toxoplasma gondii (T. gondii) is a single-celled parasitic organism that can infect most animals and birds. Because T. gondii infectious organisms are excreted only in cat feces, wild and domestic cats are the parasite’s ultimate host.

Although you can’t “catch” toxoplasmosis from an infected child or adult, you can become infected if you:

_ Come into contact with cat feces that contain the parasite. You may accidentally ingest the parasites if you touch your mouth after gardening, cleaning a litter box or touching anything that has come in contact with infected cat feces. Cats who hunt or who are fed raw meat are most likely to harbor T. gondii.

_ Eat or drink contaminated food or water. Lamb, pork and venison are especially likely to be infected with T. gondii. Occasionally, unpasteurized dairy products also may contain the parasite. Water contaminated with T. gondii isn’t common in the United States.

_ Use contaminated knives, cutting boards or other utensils. Kitchen utensils that come into contact with raw meat can harbor the parasites unless the utensils are washed thoroughly in hot, soapy water.

_ Eat unwashed fruits and vegetables. The surface of fruits and vegetables may contain the parasite. To be safe, thoroughly wash and peel all produce, especially any you eat raw.

_Receive an infected organ transplant or transfused blood. In rare cases, toxoplasmosis can be transmitted through an organ transplant or blood transfusion.

When a person becomes infected with T. gondii, the parasite forms cysts that can affect almost any part of the body — often your brain and muscle tissue of different organs, including the heart.

If you’re generally healthy, your immune system keeps the parasites in check. They remain in your body in an inactive state, providing you with lifelong immunity so that you can’t become infected with the parasite again. But if your immune system is weakened by disease or certain medications, the infection can be reactivated, leading to serious complications.

Risk factors.

Anyone can become infected with toxoplasmosis. The parasite is found throughout the world.

You’re at risk of serious health problems from toxoplasmosis infection if:

You have HIV/AIDS. Many people with HIV/AIDS also have toxoplasmosis, either a recent infection or an old infection that has reactivated.

You’re undergoing chemotherapy. Chemotherapy affects your immune system, making it difficult for your body to fight even minor infections.

You take steroids or other immunosuppressant drugs. Medications used to treat certain nonmalignant conditions suppress your immune system and make you more likely to develop complications of toxoplasmosis.

For cat lovers.

If you’re pregnant or otherwise at risk of toxoplasmosis or its complications, take these steps to protect yourself:

▪️Help your cat stay healthy. Keep your cat indoors and feed it dry or canned cat food, not raw meat. Cats can become infected after eating infected prey or undercooked meat that contains the parasite.

▪️Avoid stray cats or kittens. Although all stray animals need good homes, it’s best to let someone else adopt them. Most cats don’t show signs of T. gondii infection, and although they can be tested for toxoplasmosis, it may take up to a month to get the results.

▪️Have someone else clean your cat’s litter box. If that’s not possible, wear gloves and a face mask to change the litter. Then wash your hands well. Change the litter daily so that excreted cysts don’t have time to become infectious.

How Is Toxoplasmosis Diagnosed?Your doctor will typically perform a blood test to check for antibodies to this parasite. An antibody is a type of protein that your immune system produces when it’s threatened by harmful substances. Antibodies detect foreign substances by their surface markers, called antigens. Antigens include:▪️viruses.▪️bacteria.▪️parasites.▪️fungi.Once an antibody has developed against a particular antigen, it will remain in your bloodstream to protect against future infections with that particular foreign substance.If you’ve ever been exposed to T. gondii, antibodies will be present in your blood. This means you will test positive for the antibodies. If your tests come back positive, then you’ve been infected with this disease at some point in your life. A positive result doesn’t necessarily mean that you currently have an active infection.If your tests come back positive for antibodies, your doctor might do further testing to help figure out exactly when you were infected.If you’re pregnant and have an active infection, your doctor may test your amniotic fluid and the fetus’ blood. An ultrasound can also help determine whether the fetus has been infected.

If your fetus is diagnosed with toxoplasmosis, you’ll probably be referred to a specialist. Genetic counseling will also be suggested. The option of ending the pregnancy, depending on the gestational age of the baby, may be offered as a possibility. If you continue the pregnancy, your doctor will likely prescribe antibiotics to help reduce your baby’s risk of symptoms.

What Complications Are Associated with Toxoplasmosis?

The reason that pregnant woman should take special precautions to avoid toxoplasmosis is that it can be very serious, even fatal, for a baby infected in the uterus. For those who survive, toxoplasmosis can have lasting consequences on the:





They may also have mental and physical developmental delays and recurring seizures.

In general, babies who are infected early during the pregnancy suffer from more severe issues than those infected later in the pregnancy. Babies born with toxoplasmosis may have a higher risk of hearing and vision losses. Some children may be affected with learning disabilities.

How Is Toxoplasmosis Treated?

Your doctor may recommend not treating your toxoplasmosis if it isn’t causing any symptoms. Most healthy people who develop an infection don’t have any symptoms or develop mild symptoms that are self-limited.

If the disease is severe, is persistent, involves the eyes, or involves the internal organs, your doctor will typically prescribe pyrimethamine (Daraprim) and sulfadiazine. Pyrimethamine is also used to treat malaria. Sulfadiazine is an antibiotic.

If you have HIV or AIDS, you may need to continue these medications for life. Pyrimethamine decreases your levels of folic acid, which is a type of B vitamin. Your doctor may also ask you to take additional vitamin B while taking the drug.

Treatment During Pregnancy.

Treatment during pregnancy is somewhat different. Your course of treatment will depend on whether your unborn child is infected and the severity of the infection. Your doctor will talk with you about the best course for your particular case. Most likely, you’ll be prescribed an antibiotic according to how far along you are in your pregnancy to reduce the likelihood of transmission to the fetus. An antibiotic called spiramycin is generally recommended in the first and early second trimester. A combination of pyrimethamine/sulfadiazine and leucovorin is generally used during the late second and third trimesters.

If your unborn baby has toxoplasmosis, pyrimethamine and sulfadiazine may be considered as a treatment. However, both drugs have significant side effects on women and the fetus and are only used as a last resort. The potential side effects include suppression of the bone marrow that helps produce blood cells and liver toxicity.





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