Definition

Toxoplasmosis is an infection caused by a tiny organism called a protozoan. Many people are infected with this protozoan. However, few people have any symptoms or problems from it.

Causes

Toxoplasmosis is passed from animals to humans. People can contract it by:

• Touching infected cat feces or something that has had contact with cat feces, such as soil or insects
• Eating undercooked, infected meat, or by touching your mouth after touching the meat
• In rare cases, receiving a blood transfusion or an organ transplant

A pregnant woman who gets toxoplasmosis for the first time may pass it to her unborn child. Active infection usually occurs once in a person’s life, although the protozoan remains inactive in the body. Generally, if a woman has become immune to the infection before getting pregnant, she will not pass the condition to her baby.

Risk Factors

Factors that increase your chance of getting toxoplasmosis include:

• Babies born to mothers who are first exposed to toxoplasmosis just before becoming pregnant or during pregnancy
• People with weak immune systems from causes such as:
  • HIV/AIDS
  • Cancer
  • Organ transplant
  • Certain medications

Symptoms

Most people do not have symptoms. Those who do have symptoms may have:

• Swollen lymph nodes
• Fever
• Fatigue
• Sore throat
• Muscle aches and pains
• Rash

People with weakened immune systems may have toxoplasmosis infections in multiple organs. Infection is most common in the brain ( encephalitis), eyes ( chorioretinitis), and lungs (pneumonitis). Symptoms may include:

• Fever
• Seizures
• Headache
• Vision problems
• Problems with speech, movement, or thinking
• Mental illness
• Shortness of breath

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In babies, the severity of symptoms depends on when the mother became infected during pregnancy. If infection occurs during the first 3 months of pregnancy, babies are less likely to become infected. But if they do, then their symptoms are much more severe. During the last 6 months, babies are more likely to become infected. But, their symptoms are less serious. Toxoplasmosis can also cause miscarriage or stillbirth.

About one in 10 babies born with toxoplasmosis has severe symptoms. These include:

• Vision problems due to eye infections (chorioretinitis)
• Abdominal swelling
• Yellowing of the skin and eyes known as jaundice
• Learning disabilities
• Seizures
• Rash

Many babies infected with toxoplasmosis may seem healthy at birth. But they may develop problems months or years later. These include:

• Vision problems
• Hearing loss
• Learning disabilities
• Seizures

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. Blood tests are done to look for antibodies produced by the body to fight the toxoplasmosis. Other lab tests are done to look for the protozoa itself.

If a pregnant woman is infected, prenatal tests, including ultrasound and amniocentesis, are performed to determine if the fetus is infected.

Treatment

People who are healthy and not pregnant do not need treatment if symptoms are mild. Symptoms usually go away within a few weeks to months. People with a weakened immune system are treated with antitoxoplasmosis medications for several months.

If a pregnant woman is infected but the fetus is not, the mother is usually given an antibiotic. It can decrease the chance of the fetus becoming infected.

Fetuses with confirmed toxoplasmosis infections are treated by giving the mother a combination of these medications:

• Spiramycin
• Pyrimethamine
• Sulfadiazine
• Folinic acid

These medications can reduce the severity of, but not eliminate, a newborn's symptoms. After the baby is born, different combinations of medication will be given.

Prevention

Women who are pregnant or considering becoming pregnant should talk to their physician about taking a blood test. It will help determine if they are immune to toxoplasmosis, which would be a sign of a prior exposure. If they are not, they should take the following steps to avoid sources of toxoplasmosis:

• Do not eat raw or undercooked meat. If you touch raw meat, do not touch your eyes, mouth, or nose. Wash your hands, cutting boards, knives, and sink with soap and warm water.
• Wash all raw vegetables and fruits.
• Do not empty a cat’s litter box. Have someone else do it.
• Avoid children’s sandboxes. Cats may use them for a litter box.
• Do not feed your cat raw or undercooked meat.
• Keep your cat inside to prevent it from hunting rodents or birds that could be infected.
• Wear gloves when gardening. Keep your hands away from your eyes, mouth, and nose. Wash your hands when done.

These steps also apply to people with weakened immune systems.