Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi (T cruzi). Vector-borne transmission occurs predominately in the Region of the Americas. The insect vector is a triatomine bug that carries the parasite. Chagas disease presents itself in two phases. During the initial, acute phase, a high number of parasites circulate in the blood, but in most cases symptoms are absent or mild. Symptoms include skin lesions or purplish swelling of the lids of one eye, as well as fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling and abdominal or chest pain. During the chronic phase, the parasites are hidden mainly in the heart and digestive muscles, causing cardiac disorders and digestive, neurological or mixed alternations. In later years the infection can lead to sudden death or heart failure caused by progressive destruction of the heart muscle and its nervous system.
Chagas disease occurs mainly in Latin America. However, in the past decades it has been increasingly detected in the United States of America, Canada, and many European and some Western Pacific countries, such as Australia and Japan, mainly due to population movement between Latin America and the rest of the world. In addition, triatomine insect species – Chagas disease vectors – have been reported in the Western Pacific Region, prompting WHO to organize an informal consultation in 2011 take stock of the regional situation.