Tropical Diseases, London

The greatest risks underlying the establishment of Chagas disease in the Amazonian region of Brazil are human migration and uncontrolled deforestation. Human migration, with carriage of triatomine vectors from endemic areas, could transport the domestic cycle from established areas of domestic transmission to other areas. Deforestation can encourage adaptation of silvatic triatomine vectors to human dwellings. Since the beginning of the 1900s, it has been known that there are abundant reservoir hosts for Trypanosoma cruzi among wild animals [1,2] and several triatomine insect vector species [3,4] in Amazonian Brazil. However, the first autochthonous human cases of Chagas disease in the region were reported only in 1969, from the city of Belém, Pará State [5]. From a recent survey of case reports assembled at the Instituto Evandro Chagas, a total of 205 cases of Chagas disease have now been registered, between 1968 and 2000 [6] (Fig. 1). Of these, 178 were acute cases, nine of which were fatal, and 27 were chronic. Geographical distribution by State was as follows: 121 in Pará, 53 in Amapa, 14 in Amazonas, nine in Maranhao and eight in Acre. This is considered to be a small proportion of the real number of cases, as the distribution reflects the research interest in Chagas disease and the presence of local diagnostic facilities in Belém. The national serological survey carried out by the Brazilia