Chagas disease control in Brazil: which strategy after the attack phase?

The main target of Brazilian Chagas Disease Programme (CDP) has been the control of domestic triatomine bugs, since more than 80% of human disease is attributable to transmission by these vectors. The global CDP attack phase began in 1983, after a political and technical decision to cover all the 2,400 municipalities of the endemic area with regular insecticide spraying. At present, this vertical and almost military approach is ending, with good entomological results in nearly 70% of the whole area and drastic reduction of the disease. The consolidation of the programme now presupposes the development of a vigilance phase, carried out at regional levels and supported by intensive community participation. Not only residual triatomine foci, but chiefly those resulting from eventual house invasion by secondary sylvatic or peri-domestic species must be detected and sprayed, so avoiding new colonization. More than 700 Brazilian municipalities are in this phase, still controlled by the Ministry of Health ("SUCAM"), with regional voluntary posts established in each municipality to coordinate and respond to any denuciation of infested premises. Special attention is given to the peridomestic environment, where most of the foci are being detected after the attack phase and where the current insecticides do not work so well as indoors. The great challenge is to maintain a continuous and effective surveillance against triatomines, chiefly in the poorest and more isolated rural areas. At medium term, the trend of domestic Brazilian triatomines will depend on three different kinds of factors such as: those linked to the improvement and continuity of the programme (political decision), those that depend on human activity over the environment (extensive agriculture, deforestation, urbanization, etc.) and those associated with promotion and organization of the communities. New strategies and improvement of the existing ones must still be a target for research in the present context of Brazilian triatomines. Also, new ecological situations must be foreseen, such as the expansion of agricultural frontier, rupture of the Amazonian barrier, etc. Finally, an integrated control of Chagas Disease must emphasise complementary activities such as housing improvement and the active control of blood banks to eliminate transfusional transmission, besides the development of a realistic medical care system.