Trypanosma cruzi, the causative agent of Chagas disease (CD). Chagas Disease is endemic from the southwest USA to Patagonia. Historically, CD was a disease of poor and rural populations in Central and South America where it was transmitted primarily by triatomine insect vectors (eg: Triatoma infestans, Rhodnius prolixus). Although vector-based transmission has been controlled in many regions through massive public health programs, T. cruzi can also be transmitted by transfusion, transplantation and contaminated foods as well as vertically from mother-to-child. With the decline in vector-driven transmission, transfusion has become the major route of transmission in many parts of the Americas. Furthermore, mother-to-child transmission can maintain CD in populations long after vectoral transmission has ceased. Although congenital transmission is thought to occur in <5% of children born of CD-positive mothers, family clustering and multi-generational transmission have been reported.Both nifurtimox and benznidazole (BZN) have trypanocidal activity but only the latter is commonly used due to the risk of serious CNS and peripheral neurotoxicity with nifurtimox. Merck Frosst is designing drug to treat this disease.