Chagas' disease in the southern coastal region of Brazil

Objective To analyze serological data collected in two different periods, front the late 1960's to 1983, when these data was,first added to the available information about vector triatomines found in the state of Sao Paulo and from 1984 to 1999, a period when serology was used to describe endemic Chagas disease in the state. Methods Serological surveillance data from schoolchildren (during the late 1960s and between 1973 and 1983), and the general population (between 1980 and 1982) of the municipalities of Cananeia, Iguape and Peruibe were analyzed together with data collected on the vectors. Results Seropositivity among schoolchildren remained low and constant in the period from 1973 to 1982, and was no more detected in 1983. Cananeia showed titer distribution patterns typical of a non-endemic area, while Iguape and Peruibe indicated low endemicity. Most of the cases came from other states; autochthonous cases were suggestive of oral transmission. There were reports of infestation by vector triatomines in 1,261 domiciliary units (main species: Panstrongylus megistus and Triatoma tibiamaculata). A total of 5,338 blood samples were collected and 40 were seropositive (0.75%). Triatomines captured within domiciles were mostly adults, and about half of them having fed upon human blood. Serological results of residents living in households where triatomines infected with Trypanosoma cruzi had been found did not differ from those living in houses infested only with non-infected insects. Conclusions In addition to educational activities aimed at the local population, there is a need to develop a collaboration between scientific institutions to isolate and characterize trypanosoma strains from vectors, reservoirs (sylvatic or other) and humans. Thus, evolutional, ecological, pathological and other pertinent characteristics of different strains of such parasites could be better understood.