Neonatal Toxoplasmosis

Toxoplasmosis is an infection caused by a tiny parasite. In newborns (neonates), the infection is passed from the infant's mother while the fetus is developing in the womb. The infection usually does not cause problems for the mother. However, it can be very dangerous for a fetus that is infected while still developing. The dangers include:

  • Being born too early.

  • Being born with health problems.

  • Problems that develop months or sometimes years after infection.

The infection can affect the child's eyesight and hearing. It also may affect the child's brain.

CAUSES

The parasite that causes toxoplasmosis is usually not passed from person to person. Common causes of infection in mothers include:

  • Contact with cat waste (feces). This can happen by touching cat litter.

  • Eating undercooked meat from an infected animal.

  • Not washing your hands after handling infected meat before it is cooked.

Only pregnant women with an active infection can pass it to their fetuses. This means women must become infected while pregnant to pass on the parasite. It is rare for a woman to pass it on if she was infected before she became pregnant. Pregnant women who have been exposed should be tested.

Infections that happen early in pregnancy are often more severe. The riskiest time for the fetus is during the first 3 months of pregnancy. The chances of passing the infection to the fetus increase as the pregnancy goes on. A pregnant woman who becomes infected in the last month or so of pregnancy is almost certain to pass on the infection to her unborn child.

SYMPTOMS

A fetus infected in the womb might have symptoms at birth. Most infants infected with toxoplasmosis do not develop symptoms until later on. Symptoms may include:

  • Fever.

  • Swollen lymph nodes. These glands are all over the body. Often swelling can be felt in the neck or armpit.

  • Yellowing of the skin or eyes (jaundice).

  • Skin rashes.

  • Bruises.

  • Heart and lung problems.

  • Hearing problems.

  • Vision problems.

  • A head that is bigger or smaller than normal.

  • Learning problems.

  • Muscle problems. They may be weak. Or, the child may have muscle spasms (muscles suddenly tighten on their own).

  • Twitching or shaking (seizure).

  • Mental retardation.

DIAGNOSIS

A fetus still in the womb can be tested for toxoplasmosis. This may be done if the mother becomes infected while pregnant. More tests can be done once the infant is born.

  • Tests in the womb include:

  • Testing a sample of the liquid that surrounds the infant in the womb (amniotic fluid). Cells in this fluid are checked for signs of toxoplasmosis.

  • Fetal ultrasound. This machine uses sound waves to make pictures of the fetus inside the womb. It can show if the fetus is not developing normally, if the fetus has too much fluid in the brain (hydrocephalus), or if there are deposits of calcium inside the brain (intracranial calcifications).

  • Tests after birth may include:

  • Blood tests. These look for antibodies. Antibodies are proteins in the blood that are made to fight off things like germs. Certain antibodies develop if there is a toxoplasmosis infection.

  • Imaging tests of the brain. This includes magnetic resonance imaging (MRI) and computed tomography (CT).

  • Eye exams. Toxoplasmosis can harm the lining at the back of the eyeball (retina). The retina is responsible for sight.

Testing may need to be done often for many years. Some problems may not show up until the child is a teenager.

TREATMENT

Treatment for an infant with toxoplasmosis infection is usually most effective if it is started as soon as the infant's infection has been diagnosed. Treatment includes:

  • Pyrimethamine. This drug keeps parasites from growing and reproducing. It sometimes is given to a pregnant woman with toxoplasmosis. The goal is to keep the infection from harming the infant. It may be given to an infant born with toxoplasmosis. It can help prevent symptoms or control symptoms.

  • Antibiotics may be given to a pregnant woman or to an infant born with the infection.

  • Folinic acid. It may be given to protect the infant from side effects that pyrimethamine can cause. An example of a side effect is having too few red blood cells (anemia).

The infant's symptoms also may need to be treated. Frequent checkups may be needed for many years. Some children may need to see specialists if problems develop as a result of infection. These specialists could be ophthalmologists if vision problems develop or neurologists if the brain has been affected.