Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

pregnancy in order to prevent the acute infections occurring in early pregnancy (Henderson and Weiner 1995, Szénási et al. 1996b). The second step comes after maternal infection: i.e. the reduction and prevention of the fetal disease by the early diagnosis and treatment of toxoplasma infection during pregnancy. The third step involves the early treatment of the newborn, as well as the special follow-up of the child for at least two years. Since toxoplasmosis is generally asymptomatic in immunocompetent patients, it is rarely detected by clinical signs during pregnancy. Early identification of the infection of pregnant women followed by antiparasitic treatment is, therefore, the only practical way to reduce the incidence of congenital toxoplasmosis (Aspöck and Pollak 1992). Accurate serological methods will greatly improve the chances of diagnosis (Godard et al. 1990, Aspöck and Polkák 1992, Pinon et al. 1996). To prevent congenital toxoplasmosis, we have been routinely screening all pregnant women for toxoplasma antibody in our town, Szeged, since 1987 (Szénási et al. 1990, Szénási et al. 1991, Szénási et al. 1994, Szénási et al. 1995, Szénási and Nagy 1

996a, Szénási et al. 1996b). Here we present the results of toxoplasma screening of pregnant women between 1987 and 1995 and a detailed analysis of the serological results obtained in 1995. MATERIALS AND METHODS All pregnant women (a total of 19,985 persons) were routinely screened for toxoplasma antibody between 1987 and 1995 in the city of Szeged. Blood sampling and screening were carried out after approval by the Ethics Committee of the University (Szénási et al. 1996b). Antenatal screening First, we tested all sera by the complement fixation test (CFT) using the toxoplasma antigen of the SEVAC firm (SEVAC, Prague, Czech Republic) (Szénási et al. 1995, Szénási and Nagy 1996a, Szénási et al. 1996b). The pregnant women were tested when they were first seen at the antenatal clinics, between the 8

th and 16

th week of pregnancy. Women with moderate CFT titres (1:16-1:128) at that time were considered immune against fresh infection owing to the residual immunity left by an earlier infection: thus, they were excluded from further testing (Henderson et al. 1984). This greatly reduced the cost of the serologic surveillance. If the CFT titre was > 1:256 at the first testing, the specimen was further examined by ELISA IgG (Sanofi Diagnostics Pasteur, Paris, France, or Organon Teknika, BV Boxtel, Holland), and either by the technique of SDS-PAGE and Western immunoblot with anti-human IgG-conjugate (Reanal, Budapest, Hungary) (Verhofstede et al.. 1988, Szénási et al. 1990, Szénási and Nagy 1996a, Szénási et al. 1996b), orbyanti-P30 IgA and IgM immunocapture ELISA kits (Sanofi Diagnostics Pasteur, Paris, France) using the P30 protein as antigen (Groß et al. 1992, Groß et al. 1993, Takahashi and Rossi 1994, Decoster et al. 1995, Szénási and Nagy 1996a, Szénási et al. 1996b) in order to distinguish between the "acute" and "chronic" stages of the infection. Patients with high CFT titres but no anti-P30 IgA antibody titres were considered to have "chronic" infection. In contrast, patients with high CFT titres plus anti-P30 IgA antibody titres were considered to have "acute" toxoplasmosis. A certain part of the "acute" infections may have been acquired during pregnancy. Since the time of the acquisition of infection cannot be determined