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Toxoplasma gondii is an arc-shaped Protozoon, with parasitischer way of life. Its Endwirt are cats, as an intermediate landlord serve other vertebrate animals.
Toxoplasma gondii was discovered for the first time 1908 in Tunesien as a parasite in the Gundi (Ctenodactylus gundi) and identified as a member of the Sporozoen. Due to the half moon form it was designated of the discoverers Nicolle and Manceaux as Toxoplasma (Greek Toxon, elbow) and due to the landlord animal as Toxoplasma gondii. Only it could be found also with humans than pathogens, the illness released of them to Toxoplasmose was many later called. 1948 developed Sabin and field man a serologischen test on the basis of anti-bodies, which they called Dye test. With the help of this method it could be stated that Toxoplasma is common gondii world-wide and occurs with humans very frequently.
The parasite is world-wide common, the population exhibits high Durchseuchung, since the infection runs usually without symptoms. About 60% of the population in Germany possess anti-bodies against Toxoplasma gondii, were thus already once infected with the parasite. The rises per Lebensjahr around approximately 1%. According to estimations 7 of 1.000 pregnant women suffers an infection. After the infection a lifelong immunity exists, if the immune system is not gotten sick.
Toxoplasma gondii differs depending upon stage both in the form and in the size. The cells of the free and infectious form are arc-shaped in liquid media or fresh preparations and reach sizes of two to five micrometers. If one regards it in fabric samples or fixed to cuts, they appear egg-shaped against it oval. In addition they can occur both individually and to several in Pseudocysten so mentioned in the fabric.
The Oozysten measures the Gewebscysten up to 300 micrometers up to 11 micrometers. 2 different populations of Sporozoiten, the Tachyzoiten form form after the penetration into the intermediate landlord and increase there rapidly. Later Bradyzoiten step on their Vermehrung are strongly slowed down. Structurally these two forms do not differ.
The Oozysten is separated by the Endwirt (cat-well-behaved) with the Feces and arrives in such a way into the intermediate landlord. They contain two Sporozysten with four Sporozoiten each. They can remain infectious and project for a very long time (until 5 years) frost, are not however not very heat resistant. In the intermediate landlord (vertebrate animals and birds) the Sporocysten, this slips penetrates now actively into kernhaltige cells of the intermediate landlord (above all lymph node, Retikuloendotheliales system). Now a Vermehrung begins by ungeschlechtliche division, with which 2 daughter cells of the nut/mother cell become detached, whereby the nut/mother cell dissolves (Endodyogenie). This procedure runs off now so long, until the landlord cell is completely filled out and bursts, so that the Tachyzoiten (griech. Tachys = become fast) free. This procedure repeats itself now every 6 hours. Now the Tachyzoiten in the blood spreads and changes so also over the Plazenta into the blood. After the landlord defense used slows down the division duration and one speaks now of Bradyzoiten (griech. Bradys = slowly). Gewebezysten form particularly in the musculature in the cells, in addition, outlast latently in the brain or in the retina of the eye. In this form it then again by the cat those the intermediate landlord eats taken up. The Bradyzoiten will penetrate now in the intestine freely and into the epithelium cells. There a Schizogonie (ungeschlechtliche reproduction) takes place, finished Oozysten into the intestine will then dismiss. These are separated now with the excrement and mature in the external world in 2 - 4 days to infection-able sporolierten Oozysten near. They are years infectionable up to 5. If the Oozysten is taken up now by cats, then develop Tachyzoiten, Bradyzoiten and Gewebecysten. These remain however only to a small part in the fabric and move into the intestine epithelium of the cat where them by Schizogonie Oozysten train again. The life cycle is divided into three phases, 1.in the extraintestinale phase 2.in the external phase 3.in the enderoepitheliale phase.
With humans this parasite causes the illness Toxoplasmose. It knows T. gondii to both forms, both and Zysten in halfraw meat take up or and lubrication infection with cat excrement. He takes over then the role of the intermediate landlord, i.e. the exciters penetrate the intestine wall, in order to form in such a way in the musculature, in addition, in other organs Zysten, which outlast lifelong. Most humans go through sometime once this infection, them mostly remain without symptoms. Some months can come long to flu-similar complaints such as fever, joint and muscular pains and for example lymph node swelling. Also the Toxoplasmoseinfektion seems to limit humans substantially in its reaction rate; thus in a three-part BBC transmission on parasites it was reported that humans, who were complicated into traffic accidents were above average frequently infected. The unborn child can be heavily damaged however by T. gondii, if the Erstinfektion takes place during the pregnancy. The transmission risk decreases the weight of the damage with the duration of the pregnancy too, against it. Otherwise the Toxoplasmose can become dangerous only with weak immune system (for example AIDS).
Pregnant woman should no meat eat, which is not through-roasted and if possible not with cat excrement deal and do not work in the garden. If necessary gloves or hand washing protect against the meals. It is meaningful, if another person cleans the Katzenklo daily, because the Oozysten becomes infectious only at the earliest two days after elimination.
T. gondii belongs to the infections, on which one should test with pregnant women by routine, similarly as Syphilis, hepatitis B, Clamydien, HIV, Zytomegalie and Herpes. The investigation is in Germany however not a component of the normal pregnant woman precaution! If already in former times an infection on T were proven. gondii, no more danger assumes that. The unborn child is then protected during the pregnancy by the anti-bodies against an infection.
An infection can be proven normally most easily by immunological test procedure (ELISA, Immunofluoreszenztest), thus to proof of specific anti-bodies. IgM speak - anti-bodies for a fresh infection, IgM and a IgG anti-body together for an infection within the latter one and a half years. Both IgG and IgM forwards a so-called helps couches with the exclusion of a fresh infection.
Also molecular-biological investigations (PCR) are available are suitable for the investigation from fruit water to the proof of a transmission already taken place on the unborn child. One can diagnose a damage of the child by ultrasonic. Also with immune-weakened patients earliest the PCR or Sichtbarmachung of larger lesions already developed is suitable by means of picture-giving procedures (CT, MRT).
The diagnosis can become very difficult, if it must be placed afterwards with a newborn child, which shows disease characters only late (for example going blind by Chorioretinitis).
A Erstinfektion with T. gondii during the pregnancy must be treated with antibiotics. Otherwise a treatment can be meaningful, if the patient symptoms shows. Worked satisfactorily the combination Pyrimethamin as well as a sulfone amide or a Clindamycin. In the first three pregnancy months one can prevent only the transmission on the child by means of Spiramycin. However one is not safe, as probable a transmission is during the early pregnancy at all. Possibly the child should be still given subsequent treatment after the birth some time. All in all a damage of the child can be thus mostly prevented by this very frequent parasite.
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