[Serodiagnosis of toxoplasmosis]

Generally, toxoplasmosis has mild symptoms, or is asymptomatic, in patients with intact immune system. The infection, however, may have serious consequences in immunodeficient or immunosuppressed patients, as well as in the off-springs of pregnant women. If the mother has acute toxoplasmosis during the pregnancy, the passage of parasites through the placenta may result in the death of the fetus, or, in the severe damage of the fetus or neonate. All these consequences can be prevented by the early detection of the disease followed by the immediate therapy of the mother. Contrary to the most infectious diseases, however, the high specific IgM level has not proved to be a reliable marker of the acute infection in the case of toxoplasmosis. Therefore, in the case of infections discovered in the "plateau" period [i.e. with persistent IgM ("residual" IgM) and/or persistent high level of IgG antibody), the "acute" and the "chronic" phases can be distinguished more reliably by the detection with ELISA of the IgA antibody response to the so called P30 protein of Toxoplasma gondii. The anti-P30 IgA antibody response appears very early and generally disappears in 3-9 months. Thus, it is possible to discriminate the acute phase of the disease from the harmless chronic phase. Between 1987 and 1996, practically all pregnant women in Szeged and its region (altogether 21,952 women), underwent serologic toxoplasma screening. Among them, 124 pregnant women were found highly suspicious for having acute toxoplasmosis. Appropriate counselling, followed by spiramycin therapy during pregnancy and regular ultrasound examination were their antenatal management. No clinically manifested fetal or neonatal infection was observed. The screening and treatment schedule seems to be promising in the prevention of fetal and neonatal toxoplasmosis.