Toxoplasmosis in Pregnancy – Causes, symptoms, treatment, and prevention. How does this disease affect the fetus?

Toxoplasmosis is a parasitic disease primarily transmitted by cats. It can be contracted through contact with their feces or by consuming raw meat. It is very dangerous for the expectant mother and her child. Downplaying the symptoms and neglecting medication therapy can lead to complications during pregnancy and even result in intrauterine fetal death. Treatment for toxoplasmosis offers a chance for the birth of a perfectly healthy child.

Toxoplasmosis is divided into acquired and congenital forms, depending on the type of infection. The disease can take different forms, so pregnant women should exercise particular caution when consuming food or handling cats. It is also advisable to undergo prenatal examinations, which are usually recommended during the first trimester of pregnancy. If an infection occurs, the treating doctor should be contacted immediately.

What is toxoplasmosis?

Toxoplasmosis is a parasitic disease caused by the single-celled organism Toxoplasma gondii. The first human infections with this parasite were discovered in 1937, several years after the discovery of its existence. At that time, congenital toxoplasmosis, acquired in the womb, was diagnosed in patients. The causes of the infection were not well understood, and the developmental cycle of the parasite was still unknown. These features were discovered many years later after the first cases of the disease. The parasite is found in cat feces, on unwashed fruits and vegetables, and in raw meat. An infection can occur up to five days after direct contact.

How can one become infected with toxoplasmosis during pregnancy?

Toxoplasmosis is primarily transmitted by cats, specifically through their feces. However, this is not the only transmission route. There are three main ways of infection. The most common is the oral route. The parasite enters the body through the consumption of raw or undercooked meat, as well as through the ingestion of unwashed fruits. Drinking unfiltered water, especially from contaminated soil, also poses a risk. Cats also become infected via the oral route. Contact with cat feces also poses an infection risk.

Another route is transmission through the placenta. This occurs when the pregnant woman is actively infected with toxoplasmosis and passes the disease to the unborn child. Infection is also possible during a blood transfusion or organ transplant, but such cases are very rare.

Congenital and acquired toxoplasmosis

Toxoplasmosis is divided into congenital and acquired forms. The congenital form is diagnosed immediately after birth. It is transmitted through the placenta during pregnancy and is very dangerous for the unborn child.

The acquired form, on the other hand, is an infection caused by consuming contaminated meat or direct contact with cat feces. Initially, the infection is asymptomatic, but as the disease progresses, it can take various courses. Therefore, it is divided into different forms:

• Eye form, associated with retinitis and deterioration of vision.
• Brain form, with inflammation of the brain or its membranes.
• Lymphatic form, which is marked by significant enlargement of the lymph nodes, fever, muscle pain, and general malaise.

Acquired toxoplasmosis can also take on a generalized form, which frequently occurs in individuals with a weakened immune system or in patients with immunological diseases. In such patients, the parasite often leads to changes in the lungs or heart.

How does Toxoplasmosis manifest during pregnancy?

A pregnant woman can contract toxoplasmosis without knowing it, as the disease usually does not cause symptoms. Whether symptoms later appear depends on the woman’s immune system, age, and other health conditions. The risk of symptoms increases as the woman gets older and the weaker her immune system.

Symptoms of infection typically occur in about 10% of infected women. These symptoms resemble those associated with mononucleosis – an infectious disease that resembles the flu. Although caused by the Epstein-Barr virus, the symptoms are almost identical to those of the single-celled organism that inhabits the body. These include swollen lymph nodes, muscle aches, headaches, increased fatigue, and excessive sweating. The pregnant woman may complain of general malaise, exhaustion, and fever. Concerning symptoms should be reported immediately to the treating doctor, who will then conduct the necessary examinations.

What is the risk of infection for the child? Congenital toxoplasmosis

The unborn child can only be infected with toxoplasmosis if the mother is actively infected during pregnancy, particularly in the first few weeks after the infection begins. It does not matter whether the disease is asymptomatic or presents certain symptoms. The risk of transmission is between 30% and 40%, and the outcome depends on the stage of pregnancy. The later the trimester, the more quickly the fetus can become infected. The lowest risk of fetal infection occurs in the first trimester, but the consequences for the developing child are the most severe. In the third trimester, the risk of transmission to the fetus is much higher than at the beginning of pregnancy.

The consequences of infection are unpredictable. The parasite can lead to intrauterine fetal death, developmental disorders, or severe neurological impairments such as microcephaly, hydrocephalus, or encephalopathy. Inflammation of the retina and choroid of the eye, as well as calcified changes in the brain, are also possible. After birth, this can lead to seizures and vision problems. Such severe complications occur when the infection occurs very early in pregnancy. Fortunately, such infections are rare.

Infections most commonly occur in the later trimesters of pregnancy. They are dangerous because, after the child is born, no concerning symptoms may be observed, but the child can have an enlarged spleen and liver as well as pneumonia. Some infections may also show jaundice, and later, vision and neurological disorders may develop. If examinations confirm a toxoplasmosis infection, the child should be monitored by specialists for the next two years.

Toxoplasmosis test during pregnancy

The basis for diagnosing or excluding toxoplasmosis is a serological test for the presence of IgG and IgM antibodies. It is first carried out at the beginning of pregnancy, before the 10th week. A negative test indicates that no infection is present, but the test should be repeated prophylactically in each trimester or according to the doctor’s recommendations. The presence of IgG antibodies without IgM antibodies indicates that the woman had toxoplasmosis in the past and is immune. In this case, there is no risk of transmitting the parasite to the fetus.

The results of the toxoplasmosis test during pregnancy are difficult to interpret, so a specialist should evaluate them. The results are interpreted as follows:

• Negative IgG and IgM indicate that the woman has never been infected with Toxoplasma gondii. Therefore, she has no immunity against this disease.
• Negative IgM, positive IgG (but not too high) suggests that the woman has had toxoplasmosis and has specific defense antibodies.
• Positive IgG (especially high values), negative IgM indicates that the woman was recently infected, and it should be checked whether the parasite is still causing damage to the body. The test will be repeated after a few weeks, with additional testing of antibody avidity. Treatment is required if the test is positive again.
• Positive IgM, negative IgG indicates an ongoing infection. To avoid transmission of the disease to the child, immediate further tests and treatment are required.

The goal of prenatal screenings is to determine the timing of the toxoplasmosis infection, which is why they are so important. Through examination and the possibility of quick treatment, complications that could arise from fetal infection can be avoided.

Toxoplasmosis – Treatment during pregnancy

Treating toxoplasmosis during pregnancy is not simple, but necessary to prevent transmission of the infection to the fetus. For this purpose, the pregnant woman is given spiramycin, a macrolide antibiotic. This substance is one of the few safe options for the unborn child. However, it is only effective if no transmission to the child has occurred. If the infection is detected in the fetus via ultrasound, the medication will be switched. In this case, spiramycin will be replaced by pyrimethamine and folic acid, which can cross the placenta.

How can toxoplasmosis be prevented during pregnancy? Preventive measures

To prevent a toxoplasmosis infection during pregnancy, several rules should be followed:

• The litter box should be cleaned with gloves, ideally several times a day.
• Do not bring new animals into the house and avoid contact with wild cats.
• Wash and peel fruits and vegetables thoroughly.
• Do not consume raw or undercooked meat.
• Do not drink water from unknown sources.
• Utensils and cutlery that have come into contact with raw vegetables, fruits, or meat should be washed with warm water and soap after each use.
• Wear gloves when working in the garden or handling soil.

The most important measure is regular serological examinations, which every pregnant woman should undergo. These are done more frequently for women who have never been ill and have no antibodies in their bodies. They should have these tests performed in every trimester of pregnancy to monitor the timing of the infection.