In the first half of this century - a period of expanding coffee cultivation - there was a close relationship between the growth of cleared spaces, the domestication of triatomines, and the establishment of Chagas' disease in the state of São Paulo. However, the initiation of control mesuares in 1950 coincided with a period characterized by a progressive reversal of the conditions that had facilitated the establishment of Chagas' disease in the first place. Alterations were taking place in the agricultural environment, rural areas were becoming depopulated, and low-grade housing was being destroyed. Natural transmission of the endemic was interrupted in the mid-1970's, following the elimination of Triatoma infestans from homes. Subsequently, however, a challenge emerged from two extradomiciliary species, Triatoma sordida and Panstrongylus megistus. The invasive character of these species made it necessary to investigate their possible repercussions on human populations and to set up permanent programs of epidemiological surveillance involving direct participation by local populations.
Trypanosomiasis; Chagas' Disease; Epidemiological Surveillance; Vector Control
