Toxoplasmosis is a common infection of birds and mammals, including humans. It is produced by a small parasite called Toxoplasma gondii. A person who has had toxoplasmosis and has cured himself, cannot be infected later. For most people toxoplasmosis is not dangerous and it heals itself. If the infection is acquired by the mother during pregnancy and is transmitted to the fetus, it causes brain damage and blindness. Only a small percentage of pregnant women who are infected transmit the infection to the fetus. It is important that the pregnant woman or who wants to become pregnant should be tested to find out if she has been infected with Toxoplasma gondii and if she has not, she should be trained on how to prevent the infection.
Toxoplasmosis is caused by a small parasite that causes infection in animals and mammals, including humans. Cats are the only living carriers of the parasite. When a cat is infected, its fecal matter contains Toxoplasma gondii eggs for about 2 weeks. These eggs can survive for up to 18 months in moist soil. Ground eggs can contaminate water and plants. Cats that never leave home and do not catch mice cannot be infected with Toxoplasma gondii.
The most common modes of transmission are:
If the pregnant woman becomes infected up to 8 weeks before birth, the parasite can be transmitted to the fetus. If the infection occurred before pregnancy and the antibodies developed, the parasite can no longer be transmitted to the fetus.
Symptoms in immunocompetent persons
Most people infected with Toxoplasma gondii have no symptoms. A small percentage of patients have mild flu-like symptoms that can last for several months. Therefore, often a person does not know whether or not he has toxoplasmosis.
Symptoms in immunodeficient persons
A patient with a deficient immune system (within an HIV infection, following organ transplant or lymphoma patients) may develop a form of severe toxoplasmosis, which can lead to death. In this case, antibiotic therapy is used. A severe infection requires aggressive treatment. In very rare cases, patients with apparently healthy toxoplasmosis have developed severe symptoms due to damage to the brain, eyes, lungs or heart.
Symptoms in newborns
Most infected children have no symptoms at birth. Without treatment, these children may develop mild or severe forms of eye and brain disorders over time. Blinding can occur even 20 years after birth.
Some of the infected newborns have severe symptoms at birth, such as:
Risk factors and treatment
The risk of developing toxoplasmosis can be reduced by avoiding possible contact with sources of infection.
The risk may increase when:
Risk factors for the fetus
The more infection occurs within one month of pregnancy, the greater the risk of fetal infection. However, the earlier the fetal infection occurs, the greater the risk that the fetus will develop severe postpartum disease (after birth).
Any child born and infected with toxoplasma needs treatment to prevent further complications. Patients with a healthy immune system (immunocompetent) and who are not pregnant do not need treatment for toxoplasmosis. Any symptoms that occur will be resolved without treatment, but if the infection occurs during pregnancy treatment is necessary to protect the fetus. Because the fetal immune system is not mature enough to destroy parasites, antibiotic treatment is absolutely necessary. Children whose mothers were treated during pregnancy are healthy at birth. Newborns who were not diagnosed with the disease during pregnancy and were treated only after birth, have an increased risk of brain and eye damage before birth or in the first two years of life.
Pregnant women infected with Toxoplasma gondii are treated with antibiotics that act on the infection of the placenta. If further tests confirm fetal infection, two antibiotics will be used to reduce the effect of the parasite on the fetus. In some cases of severe early infection, fetal ultrasound can reveal serious or life-threatening fetal problems.
In these cases, one of the options presented to parents is termination of pregnancy.
Pregnant women or those who want a pregnancy in the near future, who do not know if they are immune to the parasite or who know that they are not immune, should avoid any contact with any source of infection to protect their fetus.
Thus it is recommended:
In toxoplasmosis, drugs are only given if the infection affects the fetus or an immunocompromised person. Therefore, although a pregnant woman with a healthy immune system has no risk when infected, treatment is necessary for the protection of the fetus. Pregnant women diagnosed with toxoplasmosis during pregnancy will receive antibiotic treatment. Antibiotics reduce the chances of the fetus being infected. If, however, the infection occurs (the diagnosis is made using amniocentesis) another antibiotic is added to the initial treatment.
This treatment decreases the severity of fetal toxoplasmosis and other infections-related disorders that occur after birth. If the newborn has toxoplasmosis he will receive antibiotics in the first year of life. This treatment is required to reduce the risk of brain injury and blindness caused by the infection.
- antibiotic therapy
Toxoplasma gondii infection during pregnancy can lead to brain and eye damage in the fetus and newborn. Antibiotic therapy prevents or reduces these lesions.
Initial treatment after mother's infection
When a pregnant woman is infected with Toxoplasma gondii she will be treated with antibiotics that reduce the risk of infection of the fetus. The antibiotic used is called spiramycin. Spiramycin is given orally and is concentrated in the placenta. The placenta is the place where Toxoplasma gondii reaches the fetus.
Treatment of the fetus
If amniocentesis confirms that the fetus is infected, administration of an antibiotic treatment to the mother will decrease the effects of the disease on the child and may cure the infection. Children who were treated prior to birth have a higher chance of healing than those who were initiated after birth.
Combined antibiotic therapy is most effective for fetal infection. Sulfadiazine in combination with pyrimedamine (an antibiotic commonly used against malaria) is sometimes used in combination with spiramycin.
Treatment of the newborn
The newborn infected with Toxoplasma gondii needs one year of antibiotic treatment to reduce the risk of brain and eye damage. This treatment is instituted even if the mother was treated at birth.
It may happen that antibiotic treatment during pregnancy does not cure the fetus. However, there are studies that have shown that this treatment decreases the risk of occurrence, as well as the severity of brain and eye damage.