Abstract. 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 Maternity Ward of the Hospital de Clínicas, National University of Asunción (Asunción, Paraguay), and 1,022 samples from the Regional Hospital of the San Pedro Department of Paraguay were examined. It was observed that 7.7% and 10.5%, respectively, of the pregnant women were serologically positive for infection with T. cruzi. When blood samples obtained from newborns on the day of birth or, at the most, on the first few days afterwards were examined by direct microscopic observation, an incidence of congenital transmission of 3% was found. These results are consistent with those of neighboring countries. When a serologic follow-up was conducted on the newborns until six months of age, the incidence of congenital transmission reached 10%. The same incidence rate was obtained when the samples collected during the first days after birth were examined by the polymerase chain reaction (PCR). Fiftyeight infants born to seropositive mothers were followed-up, two of which were positive by direct microscopic observation at birth, and four who were PCR-positive, but microscopy-negative at birth. None of the infants were positive for IgM at birth. The infected babies were treated with benznidazole and were followed-up by serology and PCR for four years. We conclude that the PCR has a clear advantage over conventional techniques for the early detection of congenital transmission of T. cruzi infection, and for monitoring infants undergoing chemotherapy.

Although vector transmission of American trypanosomiasis has been interrupted and there are decreased rates of new infections in large areas of Latin America, there are still many chronically infected patients. We determined the clinical and epidemiological characteristics of Trypanosoma cruzi infected patients attending the Department of Tropical Medicine of the Institute of Research in Health Sciences (IICS) from 1985 to 2007 by analyzing their clinical records, maintaining anonymity and confidentiality. The SPSS 11.5 statistical package was used to analyze 1024 patient records of whom 70.1% (723/1024) were in the age group of 21-60 years (38.7±10.5); 74.5% (763/1024) were born in endemic departments, 13.2% (135/1024) in the Central department, 5.9% (60/1024) in Asunción and 6.4% (66/1024) in other departments. At consultation, 38.2% (391/1024) lived in endemic departments, 27.8% (285/1024) in Central Department, 22.6% (231/1024) in Asunción and 11.4% (117/1024) in others. Consultation reasons were: beatings (43.5%; 445/1024), effort dyspnea (34.1%; 349/1024), enervation (32.8%; 336/1024), headache (26.1%; 267/1024) and constipation (24.7%; 253/1024), among others. Half (512/1024) said they were not bitten by kissing bugs, 26.2% (268/1024) did not know or remember, 23.8% (244/1024) were bitten and 37.6% (385/1024) had kissing bugs in their houses. About 10% (104/1024) received blood transfusion and 89.8% (920/1024) did not; 24.8% (254/1024) donated blood while 75.2% (770/1024) did not. Clinically, 73.2% (750/1024) were indeterminate patients, 16.2% (166/1024) had cardiopathy, 5.1% (52/1024) megacolon and 1.5% (15/1024) megaesophagus. Most patients were in the age group of highest economic productivity and although the majority had been born in endemic rural regions most of them were living in urban areas, likely reflecting work migration. Clinically, most patients were indeterminate and cardiac lesions predominated over digestive lesions. This is a classical chagasic