Congenital Chagas' disease in Bolivia: epidemiological aspects and pathological findings.

In 329 newborns examined by the method of Strout and/or histopathological sections of the placenta, Trypanosoma cruzi was observed in 25 cases. The serological prevalence of Chagas' disease in mothers was 51%. A greater risk of congenital transmission was observed in newborns ranging between 1,001 and 2,500 g (21%), compared to 2% in newborns weighing more than 2,500 g. Congenital transmission occurred predominantly in newborns with a gestational age of 26 to 37 weeks. Histopathological examination of placentae disclosed T. cruzi in 6.3%. In areas with a high prevalence of Chagas' disease, congenital transmission is a real hazard.