Chagas (pronounced SHA-gus) disease is named after the Brazilian physician Carlos Chagas, who discovered it in 1909. It is caused by the parasite Trypanosoma cruzi, which is transmitted to animals and people by insect vectors that are found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread). Chagas disease (T. cruzi infection) is also referred to as American trypanosomiasis.

People can become infected in various ways. In Chagas-endemic areas, the main way is through vectorborne transmission. The insect vectors are called triatomine bugs. These blood-sucking bugs get infected by biting an infected animal or person. Once infected, the bugs pass T. cruzi parasites in their feces. The bugs are found in houses made from materials such as mud, adobe, straw, and palm thatch. During the day, the bugs hide in crevices in the walls and roofs. During the night, when the inhabitants are sleeping, the bugs emerge. Because they tend to feed on people’s faces, triatomine bugs are also known as “kissing bugs.” After they bite and ingest blood, they defecate on the person. The person can become infected if T. cruzi parasites in the bug feces enter the body through mucous membranes or breaks in the skin. The unsuspecting, sleeping person may accidentally scratch or rub the feces into the bite wound, eyes, or mouth.