TREATMENT OF CONGENITAL CHAGAS-DISEASE DIAGNOSED AND FOLLOWED UP BY THE POLYMERASE-CHAIN-REACTION

In 1991 and 1992, a prenatal screening of Trypanosoma cruzi infection was carried out using ELISA and indirect immunofluorescence techniques . A total of 840 blood samples from pregnant women, obtained at the Ma ternity Ward of the Hospital de Clinicas, National University of Asunc ion (Asuncion, Paraguay), and 1,022 samples from the Regional Hospital of the San Pedro Department of Paraguay were examined. It was observe d that 7.7% and 10.5%, respectively, of the pregnant women were serolo gically positive for infection with T. cruzi. When blood samples obtai ned from newborns on the day of birth or, at the most, on the first fe w days afterwards were examined by direct microscopic observation, an incidence of congenital transmission of 3% was found. These results ar e consistent with those of neighboring countries. When a serologic fol low-up was conducted on the newborns until six months of age, the inci dence of congenital transmission reached 10%. The same incidence rate was obtained when the samples collected during the first days after bi rth were examined by the polymerase chain reaction (PCR). Fifty-eight infants born to seropositive mothers were followed-up, two of which we re positive by direct microscopic observation at birth, and four who w ere PCR-positive, but microscopy-negative at birth. None of the infant s were positive for IgM at birth. The infected babies were treated wit h benznidazole and were followed-up by serology and PCR for four years . We conclude that the PCR has a clear advantage over conventional tec hniques for the early detection of congenital transmission of T. cruzi infection, and for monitoring infants undergoing chemotherapy.