Chagas disease (also called American trypanosomiasis) is a human tropical parasitic disease which occurs in the Americas, particularly in South America. Its pathogenic agent is a flagellate protozoan named Trypanosoma cruzi, which is transmitted to humans and other mammals mostly by hematophagous assassin bugs of the subfamily Triatominae (Family Reduviidae). Those insects are known by numerous common names varying by country, including benchuca, vinchuca, kissing bug, chipo, barbeiro,etcetera. The most common insect species belong to the genera Triatoma, Rhodnius, and Panstrongylus. Other forms of transmission are possible, though, such as ingestion of food contaminated with parasites, blood transfusion and fetal transmission.
Trypanosoma cruzi is a member of the same genus as the infectious agent of African sleeping sickness, but its clinical manifestations, geographical distribution, life cycle and insect vectors are quite different.
The disease was named after the Brazilian physician and infectologist Carlos Chagas, who first described it in 1909, but the disease was not seen as a major public health problem in humans until the 1960s. He discovered that the intestines of Triatomidae harbored a flagellate protozoan, a new species of the Trypanosoma genus, and was able to prove experimentally that it could be transmitted to marmoset monkeys which were bitten by the infected bug.