American trypanosomiasis (Chagas' disease)—the infection of man with Trypanosoma cruzi—was first described in 1909 by Carlos Chagas when he found the organism in the blood of a Brazilian child. This trypanosome had been discovered previously by him in the intestine of a triatomid bug, and he later traced the life cycle of the parasite from animal reservoir hosts, via the triatomid, to man. In subsequent years many investigators have added information on the distribution of the parasite (in animals and insects) through various parts of North and South America. In the course of these studies, naturally infected triatomids were found in California and Arizona. Similarly infected insects were found in Texas. In Texas, armadillos, opossums, mice, and wood rats have been shown to be naturally infected. Despite this association of a natural animal reservoir and infected insect vectors, no instance of the infection in man has been reported as occurring