Trypanosoma cruzi seroprevalence in pregnant women and screening by PCR and microhaematocrit in newborns from Guanajuato, Mexico.

Chagas disease is caused by an infection with the protozoan hemoflagellate Trypanosoma cruzi, and it is a major endemic health problem in Latin America. The congenital route is one of the main non-vectorial pathways of transmission, which can arise either in the chronic or acute phase of maternal infection. Serological screening of T. cruzi infection was performed in 520 pregnant women and newborns at the Hospital General Regional de León, Guanajuato, Mexico, between 2014 and 2015. Anti-T. cruzi antibodies were detected in 20 mothers (4%) by ELISA and HIA with four PCR-positive newborn cases. Risk factors were identified according to an epidemiological survey, and the most significant (P<0.050) factors associated with T. cruzi infection were the building materials of dwellings, the presence of pets and dwellings located in rural areas. This study constitutes the first systematic study on congenital Chagas disease and the epidemiological risk factors in Guanajuato. Our results represent the probability of an incidence of 770 cases per 100,000 births during a period of 12 months, with a vertical transmission rate by 0.8%, which highlights the necessity to establish reliable serological and PCR tests in pregnant women to prevent vertical transmission. However, it is also important to follow-up the newborns from seropositive mothers for one year, which is necessary, as many children yielded negative results.