The protozoan flagellate Trypanosoma cruzi is the causative agent of Chagas’ disease and has been estimated to infect between 10 and 12 million people in Central and South America (WHO 1960). T. cruzi has a complex life cycle involving stages in both a vertebrate and an insect vector host, the reduviid or assassin bugs, members of the subfamily Triatominae. Transmission of infective metacyclic trypomastigotes to the vertebrate host occurs following feeding and defecation by the bug and contamination of a wound site or penetration of nearby mucous membranes by the parasite. T. cruzi is thus placed in the class Stercoraria in contrast to the pathogenic African trypanosome species, which are Salivaria, whose transmission to the vertebrate occurs by inoculation via the insect’s salivary glands.