Short Report Detectable Trypanosoma cruzi Parasitemia during Pregnancy and Delivery as a Risk Factor for Congenital Chagas Disease

Vector control has led to a drastic decrease in the prevalence of acquired Chagas disease in Latin America thus redirecting attention to congenital Chagas disease We report results of a longitudinal study of 359 pregnant women in Yacuiba in southern Bolivia, of whom 147 (40 9%) were infected with Trypanosoma cruzi, to evaluate the relation ship between the patency period of the parasitemia and the risk of congenital infection Maternal infection was assessed by using T cruzi-specific serologic tests and parasitemia in mothers and newborns was diagnosed by using microscopic examination of blood in heparinized microhematocrit tubes Parasitemia was present in 28 6% of the infected women Its prevalence increased during the third trimester then decreased at delivery The likelihood of congenital infection was significantly correlated with the parasite density in the mother s blood The risk of transmission increased during the third trimester of pregnancy and could explain premature births or low weight newborns for infected mothers