This study describes the results of the health programme implemented in the Valencian Community (Spain) to achieve an early diagnosis of Chagas disease in pregnant Latin American women and their newborns. During 2009 and 2010, 1975 women living in the health districts of three university hospitals were enrolled via midwives or at the time of delivery. Diagnosis of disease was performed using two serological tests with different antigens. Congenital infection was diagnosed by parasitological, molecular or serological methods from blood samples obtained at birth or in subsequent controls. The overall seroprevalence of Chagas infection in pregnant women from 16 different endemic countries was 11·4%. Infection was higher in those from countries in the Gran Chaco Region (Bolivia, 34·1%; Paraguay, 7·4%; Argentina, 5·3%). Eight newborn infants from Bolivian mothers had congenital Chagas which represents a vertical transmission rate of 3·7%. In conclusion, this work supports the benefits of offering an early diagnosis to pregnant women and newborns during routine prenatal healthcare.

Chagas disease is, among others, considered a neglected tropical disease. Given the magnitude of the human movements that have occurred in recent years from Central and South America to other countries, Chagas should now be considered a disease of worldwide distribution, in which the transmission of the parasite is restricted to transplacental transmission or blood or organ donations from infected people. Parasite detection in chronically ill patients is restricted to serological tests that only determine previous contact and not the presence of the parasite, especially in those patients undergoing treatment evaluation or in newborns. In this study, we evaluate the use of nucleic acids from both circulating serum exovesicles and cell-free DNA cfDNA from 448 serum samples from immunologically diagnosed chronic chagasic patients, which were re-evaluated by nested PCR on the amplicons resulting from amplification with kDNA-specific primers 121F, 122R. Of the total number of samples selected, 50 were used to isolate and purify exovesicles from circulating serum and cell-free DNA (cfDNA). When the nucleic acids thus purified were assayed as a template and amplified with primers 121F-122R and SAT, a percentage positivity of 100% was obtained for all positive samples assayed with the kDNA-specific primers and 96% when SAT primers were used. However, isolation of cfDNA for T. cruzi and amplification with SAT primers also showed 100% positivity. Hence, both samples can be used in those cases where it is necessary to demonstrate the active presence of the parasite.