RESUMO
During a study on prevalence of parasitic and viral serological markers in pregnant adolescents, a 17-years-old primipara from Polpaico, village near Santiago, gave birth to a normal male newborn in a Santiago hospital. As both of them presented positive an indirect hemaglutination test (IHAT) for Chagas's disease and the corresponding xenodiagnosis (XD), the infection in the infant was considered to be acquired through the placental route. According to recent epidemiologiacal surveys Polpaico is an endemo-enzootic chagasic rural settlement, where 14.7% of dwellings were infested with Triatoma infestans, while triatominae, persons and domestic mammals were found infected with Trypanosoma cruzi. One month later the adolescent mother, her son and other 11 consanguineous members of the family were visited in their homes in order to submit each of then to a physical examination and to IHAT for Chagas' disease, and XD to those whose IHAT resulted positive. Thus, in 7 (53.8%) the IHAT was positive and in 4(57.1%) out pf these 7 presented positive the XD, results that as a whole yelded a household chagasic endemics