Toxoplasma gondii is one of the world’s most common parasites. It is the second leading cause of deaths attributed to foodborne illness in the United States, and the third leading cause of foodborne illness hospitalizations. It is estimated that 22.5% of the population over the age of 12 has been infected with the Toxoplasma parasite. For some populations, this figure is as high as 95%.
The most common sources of toxoplasmosis, the disease caused by Toxoplasma, are undercooked meat, animal feces, and transmission from mother to unborn child. Toxoplasma from animal feces can contaminate soil or water. Cats commonly contribute to the spread of Toxoplasma infection by eating small animals carrying the parasite and passing it on through their feces. While most people infected with Toxoplasma experience no symptoms, unborn children (who contract it from their mothers) and adults with compromised immune systems risk serious side effects.
Symptoms of Toxoplasmosis
Healthy individuals usually become infected with Toxoplasma without exhibiting any symptoms, as their immune systems are able to keep them from experiencing illness. If symptoms do occur, they generally take the form of mild "flu-like" symptoms, such as headache, muscle aches, fever and sore lymph nodes. These can last for several weeks.
Toxoplasmosis in Infants
Mothers with toxoplasmosis have approximately a 30 percent chance of passing the disease on to their unborn child. An infant’s risk of infection increases as the pregnancy progresses, but the severity of the infection decreases further on into the pregnancy. Infection early in the pregnancy often leads to miscarriage or stillbirth, and children who survive are often born with the following complications:
An enlarged liver and spleenJaundiceSevere eye infections
Most infants infected with toxoplasma, however, don’t show symptoms of infection until later in life. These can include:
- Loss of hearing
Mental retardationSerious eye infections that may lead to blindness
Toxoplasmosis in Immunocompromised Individuals
Symptoms among those with compromised immune systems include:
ConfusionPoor CoordinationSeizuresLung problemsBlurred vision
Diagnosis of Toxoplasma Infection
Taxoplasmosis is often difficult to diagnose, since symptoms are often similar to those of the flu and mononucleosis.
To test for infection in pregnant women, a doctor may conduct a blood test. The Centers for Disease Control and Prevention (CDC) recommends that tests be sent to a laboratory specializing in toxoplasmosis diagnosis.
Toxoplasma infection in babies may be detected using a variety of tests. Two of the most common include:
- Amniocentesis: A test of fluid from the amniotic sac surrounding the fetus.
Ultrasound scan: The ultrasound can reveal signs of infection, although a baby who doesn’t display signs could still be infected.
Severe cases of toxoplasmosis in adults may be diagnosed using imaging tests such as an MRI or a brain biopsy to check for lesions or cysts in the brain.
Treatment for Toxoplasma Infection
Most healthy people do not require treatment for toxoplasmosis. However, otherwise-healthy individuals who experience severe symptoms of the disease can be treated with drugs, including Daraprim, an antimalarial drug, or Sulfadiazine, an antibiotic. The same drugs can be used to treat those with compromised immune systems. In extreme circumstances, these drugs can be administered to unborn babies to prevent further development of the infection, but cannot undo damage that has already occurred.
If a pregnant woman is diagnosed with toxoplasmosis, she may be given Spiramycin, an antibiotic, to reduce the chance the infection will spread to the child. While the drug is still considered experimental in the US, doctors can obtain in from the FDA.
Preventing Toxoplasma Infection
Toxoplasma in the Environment
To reduce the risk of contracting toxoplasmosis from sources in the environment, take the following precautions:
- Wear gloves when gardening
Cover children’s sandboxes when not in useAvoid drinking untreated waterExercise extreme caution when changing cat litter, washing hands thoroughly afterwardsDo not adopt stray cats or kittensKeep cats indoors
Toxoplasma in Food
- Wash hands thoroughly before and after preparing food
Wash or peel all fruits and vegetables before consumptionDo not drink unpasteurized milkWash kitchen utensils thoroughly after useCook meat to an internal temperature of 160⁰F
"Toxoplasmosis." Centers for Disease Control and Prevention (2008). Available at http://www.cdc.gov/toxoplasmosis/.
"Toxoplasmosis." Mayo Clinic (2010). Available at http://www.mayoclinic.com/health/toxoplasmosis/DS00510.