Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 31. (Budapest, 1998)

earlier the fetus is infected the greater the risk of severe damages. This led to the estimation that infections in the third trimester of pregnancy are associated with increased transmission of T. gondii but also with less severe manifestations of congenital toxoplasmosis compared to infections at 10-24 weeks, when the risk of severe fetal toxoplasmosis is the greatest (Grover et al. 1990; Lynfield and Eaton 1995). Therefore, a screening project was established in 1987 for the early detection of congenital toxoplasmosis in pregnant women in Szeged, Hungary (Szénási et al. 1997a; Szénási et al. 1997b). Women showing serological results raising the suspicion of acute toxoplasmosis (seroconversion, high or rising complement fixation (CF) titres and anti-P30 IgA positivity) were immediately given the adequate therapy during their pregnancy to prevent severe fetal damages. The follow-up of these cases has been continued by a group of parasitologists, obstetricians, paediatricians, infectologists, ophthalmologists and neurologists. In these newborns at risk, detection of CF or IgG antibodies in

; cord blood and infants' serum is not informative because of maternal passive transfer. In contrast, anti-P30 IgM or IgA antibodies are not able to pass the placenta and could be more successfully used for the detection of congenital toxoplasmosis (Desmonts et al. 1985; Szénási et al. 1996-1997; Szénási et al. 1997a, Szénási et al. 1997b). Detection of IgM antibodies may have some value although they may be present in the blood for more than 1 year (Lynfield and Eaton 1995). Contamination of the cord blood sample with maternal blood during birth may result in false positive IgA antibody titers (Fuentes et al. 1996) or frequently these antibodies are absent from, or not detectable, in the serum of newborns (Fuentes et al. 1996). Confirmation of congenital toxoplasmosis can be based on isolation and growth of the parasite in mice or cell culture which are time consuming with a proven reliability of no more than 64 % of the cases (Grover et al. 1990). One of the rapid alternatives that has been tested on clinical specimens of symptomatic newborns is a method to detect the presence of part of the parasite's genome. The assay is based on in vitro amplification of a sequence of DNA of the T gondii 35-fold repetitive Bl gene of unknown function by the PCR (Burg et al. 1989). Perinatal diagnosis of symptomatic congenitally infected neonates by using PCR and urine has been shown to be rapid and highly sensitive (Fuentes et al. 1996). The purpose of the study was to compare the PCR test from urine samples with serological results of asymptomatic newborns born to women with serological evidence of acute toxoplasmosis treated by spiramycin. MATERIALS AND METHODS Patients: Asymptomatic newborns of 33 pregnant women in whom Toxoplasma infection acquired during pregnancy was detected by systematic serological screening (Szénási et al. 1997a; Szénási et al. 1997b) were selected for PCR examination. Instead of blood samples, urine specimens were preferred because they can be easily (non-invasively) collected from infants. Tachyzoites of T. gondii as positive controls were maintained in our laboratory by intraperitoneal infection of mice. Reagent blanks were processed as negative controls. Molecule weight standard was obtained by BspRl restriction endonuclease digestion of pUC19 plasmid.