Chagas disease, or American trypanosomiasis, is caused by the parasite Trypanosoma cruzi. Infection is most commonly acquired through contact with an infected triatomine bug (or "kissing bug," because it often bites the face). Infection can also occur from mother to baby (congenital), contaminated blood products (transfusions), or an organ transplanted from an infected donor. Chagas disease occurs mainly in Latin America, where an estimated 8 million to 11 million people are infected. People living in rural areas are at greatest risk. Most individuals with Chagas disease in the United States acquired their infections in other countries. Although there are triatomine bugs in the United States, only rare cases originating in the United States have been documented. The November 14, 2007, issue of JAMA includes an article about Chagas disease.