Chagas disease is a parasitic disease caused by the parasite Trypanosoma cruzi, a type of single celled organism. The parasite is usually transmitted by an insect bite, although it can survive outside the body and be ingested (often in vegetables) or transmitted through the blood.
The disease is generally chronic and causes few or no symptoms. However, it can still be fatal even if it never reaches the acute stage. In the acute stage, it causes heart and intestinal problems.
The disease is endemic in tropical areas of the Americas, and affects an estimated 6-11 million people. However, the parasite is unable to survive in colder climates, and it is also unknown in the Old World.
See also African trypanosomiasis, which is a similar disease.