Toxoplasmosis is an infection caused by a tiny organism called a protozoon. Many people are infected with this protozoon. However, few people have any symptoms or problems from it.
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 one time in a person’s life, although the protozoon 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.
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:
- Organ transplant
- Certain medications
Most people do not have symptoms. Those who do have symptoms may have:
- Swollen lymph nodes
- Sore throat
- Muscle aches and pains
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:
- Vision problems
- Problems with speech, movement, or thinking
- Mental illness
- Shortness of breath
In babies, the severity of symptoms depends on when the mother became infected during pregnancy. If infection occurs during the first three months of pregnancy, babies are less likely to become infected. But if they do, then their symptoms are much more severe. During the last six 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)
- Enlarged liver and spleen
- Jaundice (yellow skin and eyes)
- Myocarditis (inflammation of the heart)
- Brain malformations
- Intellectual disability
- Cerebral palsy
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
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.
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 medicines 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:
- Folinic acid
These drugs can reduce the severity of, but not eliminate, a newborn's symptoms. After the baby is born, different combinations of medication will be given.
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.
Kids Health—Nemours Foundation
US Centers for Disease Control and Prevention
Women's Health Matters
ACOG practice bulletin. Perinatal viral and parasitic infections. Number 20, September 2000. Int J Gynaecol Obstet. 2002 Jan;76(1):95-107.
Parasites—toxoplasmosis (toxoplasma infection). Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/parasites/toxoplasmosis. Updated January 10, 2013. Accessed November 3, 2014.
Toxoplasmosis. Nemours KidsHealth.org website. Available at: http://kidshealth.org/parent/infections/parasitic/toxoplasmosis.html. Updated September 2011. Accessed November 3, 2014.
Last reviewed December 2014 by Kari Kassir, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.