Definition
Toxoplasmosis is an infectious disease caused by the unicellular organism Toxoplasma gondii. The first description of toxoplasmosis dates back to 1923, but it was not fully understood until almost 50 years later. Toxoplasmosis usually proceeds without further symptoms and is usually harmless.
For people with a weak immune system or a first infection during pregnancy for unborn children is considered dangerous. The symptoms of toxoplasmosis manifest themselves in many different ways. After an infection with Toxoplasma gondii, the affected person is immune to the infection for the rest of his life and cannot contract it again.
This also applies to the pregnant woman, so that in this case there is no risk of infection for the unborn child (fetus). If a toxoplasmosis infection occurs during pregnancy with damage to the child, this must be reported anonymously, i.e. without a name, according to the Infection Protection Act. This infection can have serious consequences for the premature baby. As a result of damage to the brain, spastic cerebral palsy can develop.
Occurrence in the population
The toxoplasmosis pathogen occurs worldwide. It is also very widespread in the population, so that three-quarters of all people over the age of 50 carry the pathogen in themselves or at least have had contact with the pathogen before. In about half of all pregnant women, antibodies are found in the blood. These indicate an earlier infection with Toxoplasma gondii.
Cause
The toxoplasmosis pathogen, Toxoplasma gondii, is a unicellular organism that can infect humans, among others, and which nests in various body cells and lives here as a parasite. However, until the pathogen reaches humans, it is subject to its own developmental cycle. The sexual reproduction of Toxoplasma gondii takes place in the small intestine of cats.
During this process, so-called oocysts (type of egg cells) are produced, which the cat excretes with its faeces in its environment. Here the oocysts go through different stages of development during the following days and finally remain in the form of sporozoites (type spores). In this stage they can remain infectious for months.
Toxoplasma gondii is now transmitted through raw, uncooked meat containing the cysts or after contact with cat feces, for example when playing in the sandbox or cleaning the cat toilet. The toxoplasmosis pathogen is also able to pass through the placenta and reaches the fetus. This form of pathogen transmission is called transplacental and represents the only possibility of transmission from person to person.
After the pathogen has been ingested orally (through the mouth) through food or because of dirty hands, the unicellular organism spreads through the blood. In the process, it first attacks cells of the immune system. In these cells it begins to divide and fills the cell with more and more parasites.
Then the cell decays and the pathogens enter the blood and spread throughout the body. In this way it reaches all organs. If the immune system notices the invading parasite, it starts to defend itself about 6 days after the infection.
This creates small cavities with a tissue barrier (cyst) in which the pathogens are located. The cysts develop mainly in muscles and in the brain. These cysts make the parasites resistant and can thus remain viable for a long time (persistent).
To make sure that the pregnant woman is infected with Toxoplasma gondii, her blood is examined. The search for specific antibodies is carried out. The detection of antibodies can also determine whether the toxoplasmosis infection occurred before the pregnancy or whether the pregnant woman has contracted toxoplasmosis for the first time.
This is done with the help of the different antibody subgroups. Thus, initial infections lead to the formation of antibodies of the group μ, which are called IgM antibodies. If an infection occurred earlier, the group ?
is found, which is called IgG antibodies. These IgG-antibodies can be detected for life. It is also possible to determine the pathogen by means of specific staining of samples from different organs, for example the placenta.
Slight or symptomless infections of toxoplasmosis are not treated with drugs.Basically the therapy consists of the administration of antibiotics. Toxoplasmosis is treated with a single antibiotic such as spiramycin until the 16th week of pregnancy. In the course of the later pregnancy, combinations of antibiotics are administered.
The therapy of the pregnant women also counteracts the transfer of the infection to the child. Newborns also contain a combination of different antibiotics for 6 to 12 months depending on the scheme. Even people with a poor immune system (e.g. AIDS sufferers) are treated with antibiotics.
If the toxoplasmosis is acquired after birth and the patient has his complete immune function, the prognosis of the course of the disease is good. If the infection occurs during pregnancy, the further course of the disease depends on the time and extent. Only about 10% of prenatally infected children are actually born with the above-mentioned disorders.
The vast majority are therefore healthy. However, some of them may show developmental disorders and the like in the further course of the disease. Persons with a weakened immune system often suffer from toxoplasmosis in addition to the above-mentioned symptoms, such as inflammation of the brain (encephalitis) or inflammation of the lungs (pneumonia) or heart (myocarditis).
In these patients, therapy must be started, otherwise the infection will be fatal in most cases. Especially pregnant women or people with a weakened immune system should take care to avoid toxoplasmosis. The avoidance of raw, uncooked meat plays an important role in this respect.
Processing meat by cooking, smoking or curing kills the parasites. Vegetables, especially salad, should also be washed before eating. Washing hands after contact with raw meat or after working in the garden is a useful preventive measure.
Nutrition The contact with cats has to be done hygienically with subsequent hand washing. In domestic cats whose food does not contain raw meat, there is no possibility of infection for the owners. Freewheeling cats can ingest the toxoplasmosis pathogens via mice or similar and infect humans in their environment.
There is a test (screening) which can detect earlier, even undetected, toxoplasmosis. However, this test is not included in the official maternity guidelines, so it is not performed automatically. The test is useful for early detection and treatment of pregnant women infected with Toxoplasma gondii.
But also to instruct not yet infected mothers to be more careful when handling cats and meat. Breastfeeding mothers should also continue to handle any infected materials carefully and preventively, e.g. by washing their hands.
