Life Cycle of Chagas Disease. An infected insect sucks blood and releases trypomastigotes in its feces near the site of the wound. Trypomastigotes enters the host through the wound and invades cells and differentiate into intracellular amastigotes. The amastigotes multiply by binary fission and differentiate into trypomastigotes, and then are released into the circulation as bloodstream trypomastigotes. The bug itself becomes infected by feeding on human or animal blood that contains circulating parasites.