[Chagas' disease].

Chagas disease, named after the Brazilian physician Carlos Chagas who fi rst described it in 1909, exists only on the American continent (Chagas 1909). It is caused by a fl agellate protozoan parasite Trypanosoma cruzi transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases: acute and chronic. The acute phase lasts six to eight weeks. Once the acute phase subsides, most infected patients recover an apparently healthy status, in which no organ damage can be demonstrated by the current standard methods of clinical diagnosis. The infection can be verifi ed only by serological or parasitological tests. This form of the chronic phase of Chagas disease is called the indeterminate form. Most patients remain forever in this form of the disease. However, several years after of starting the chronic phase, and depending on the geographical area, 10–40 per cent of the infected individuals will develop lesions of different organs, mainly the heart and the digestive system. These conditions are called the cardiac or digestive forms of chronic Chagas disease. The chronic phase lasts the rest of the life of the infected individual. Chagas disease is the primary cause of cardiac lesions in young, economically productive adults in the endemic countries in Latin America. It has been targeted for elimination by the World Health Assembly in Resolution WHA51.14, approved in May 1998 (World Health Organization 1998b).