Chagas_disease Chagas disease (, , mal de Chagas in both languages; also called American trypanosomiasis) is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking assassin bugs of the subfamily Triatominae (family Reduviidae) most commonly species belonging to the Triatoma, Rhodnius, and Panstrongylus genera.