Congenital Toxoplasmosis: Causes, Symptoms & Treatments

Picture of Congenital Toxoplasmosis


What is Congenital Toxoplasmosis?

Congenital toxoplasmosis is a disease that occurs in fetuses infected with Toxoplasma gondii, a protozoan parasite, which is transmitted from mother to fetus. It can cause miscarriage or stillbirth. It can also cause serious and progressive visual, hearing, motor, cognitive, and other problems in a child.

How Congenital Toxoplasmosis Spreads?

People can catch toxoplasmosis from:

  • touching or coming into contact with infected cat feces (poop). A cat can become infected from eating infected rodents, birds, or other small animals.
  • eating raw or undercooked meat (especially lamb, pork, and venison) from animals that were infected
  • eating raw, unwashed fruits or vegetables that have touched manure
  • being born with it (a woman who gets toxoplasmosis while pregnant may pass the parasite to her unborn child through the bloodstream)
  • accidentally ingesting (swallowing) the eggs of the parasite, which can get on the hands after handling soil without gloves or handling uncooked, unwashed foods
  • drinking contaminated water

Although infection doesn’t normally spread from person to person except through pregnancy, in rare instances toxoplasmosis can contaminate blood transfusions and organs donated for transplantation.

Causes of Congenital Toxoplasmosis

Toxoplasmosis infection can be passed to a developing baby if the mother becomes infected while pregnant. The infection spreads to the developing baby across the placenta. Most of the time, the infection is mild in the mother. The woman may not be aware she has the parasite. However, infection of the developing baby can cause serious problems. Problems are worse if the infection occurs in early pregnancy.

Symptoms and Signs of Congenital Toxoplasmosis

Pregnant women infected with T. gondii generally do not have clinical manifestations, but some may have a mild mononucleosis-like syndrome, regional lymphadenopathy, or occasionally chorioretinitis. Similarly, infected neonates are usually asymptomatic at birth, but manifestations may include

  • Prematurity
  • Intrauterine growth restriction
  • Jaundice
  • Hepatosplenomegaly
  • Myocarditis
  • Pneumonitis
  • Various rashes

Neurologic involvement, often prominent, includes chorioretinitis, hydrocephalus, intracranial calcifications, microcephaly, and seizures. The classic triad of findings consists of chorioretinitis, hydrocephalus, and intracranial calcifications. Neurologic and ophthalmologic sequelae may be delayed for years or decades.

Treatment for Congenital Toxoplasmosis

Spiramycin can treat infection in the pregnant mother.

Pyrimethamine and sulfadiazine can treat fetal infection (diagnosed during the pregnancy).

Treatment of infants with congenital toxoplasmosis most often includes pyrimethamine, sulfadiazine, and leucovorin for one year. Infants are also sometimes given steroids if their vision is threatened or if the protein level in the spinal fluid is high.

Prevention of Congenital Toxoplasmosis

Pregnant women should be counseled to avoid contact with cat litter boxes and other areas contaminated with cat feces. Because oocysts require > 24 h after excretion to become infectious, conscientiously changing the entire litter box on a daily basis while wearing gloves followed by careful handwashing should reduce infection by this route.

Meat should be thoroughly cooked before consumption by pregnant women. Fruits and vegetables should be washed thoroughly or peeled, and all food preparation should be followed immediately by handwashing.

Women at risk of primary infection (eg, those frequently exposed to cat feces) should be screened during pregnancy. Women infected during the 1st or 2nd trimester should be counseled regarding available treatments.