Neonatal screening for congenital toxoplasmosis in a cohort of 165 women infected during pregnancy and influence of in utero treatment on the resultsof neonatal tests

The aim of this study was to determine the performances of methods used for the neonatal diagnosis of congenital toxoplasmosis. We included 165 pregna nt women infected during pregnancy over a 10-year period. Fifty-seven cases of congenital toxoplasmosis were demonstrated (34.5%). Neonatal diagnosis gave positive results in 50 cases (88%). Parasites were isolated from place nta or cord blood in 61% of the infected newborns, more frequently from pla centa (60%) than from cord blood (43%). This method was the only criterion of infection in 18% of these infected infants. The detection of specific Ig M and IgA antibodies performed on 42 sera of infected infants allowed the d iagnosis of congenital infection in 34 cases (81%). IgA antibodies were mor e frequently detected (60%) than specific IgM (50%). Neonatal and prenatal screening were carried out for 143 pregnant women. This combination diagnos ed 39 of 40 infected infants (98%). Prenatal diagnosis identified 30 of 40 cases (75%). Nine cases were diagnosed through neonatal screening and one c ase with the postnatal follow-up. When prenatal diagnosis was positive, pyr imethamine and sulfadoxine were administered to the mothers (25 cases) in a ddition to spiramycin. Toxoplasma gondii was less frequently isolated in th e placenta and the cord blood of these women (32% and 19%, respectively) th an in women treated by spiramycin alone (83% and 63%) proving the antiparas itic action of these drugs. In conclusion, neonatal screening combining par asite detection in placenta and immunological methods on cord blood is esse ntial particularly when prenatal diagnosis is negative. Therefore, when thi s diagnosis is positive, a treatment with pyrimethamine and sulfamide can b e started in the first month of life. (C) 2001 Elsevier Science Ireland Ltd . All rights reserved.