Phylogenetic analysis of Trypanosoma cruzi from pregnant women and newborns from Argentina, Honduras and Mexico reveals a possible association of parasite haplotypes with congenital transmission of the parasite

Abstract Trypanosoma cruzi, the causative agent of Chagas disease, exhibits a high genetic variability and has been classified into six discrete typing units (DTUs) named TcI-TcVI. This genetic diversity is believed to be associated with clinical characteristics and outcomes, but evidences supporting such associations have been limited. Here we performed a phylogenetic analysis of T. cruzi sequences of the mini-exon intergenic region obtained from a large cohort of pregnant women and newborns from Argentina, Honduras, and Mexico, to assess parasite genetic diversity and possible associations with congenital transmission. Analysis of 105 samples (including five paired samples) from maternal and umbilical cord blood indicated that T. cruzi DTU distribution was similar among pregnant women and newborns from these three countries, with a high frequency of TcII-TcV-TcVI DTUs, including mixed infections with TcI. However, phylogenetic analysis revealed that although the same parasite haplotypes circulated in these three countries, they were present at different frequencies, leading to significant geographical differences. Of importance, a strong association was observed between parasite haplotypes and congenital infection of newborns. Thus, the identification of parasite haplotypes in pregnant women, but not of parasite DTUs, may help predict congenital transmission of T. cruzi.