Between the years 1976 and 1980, the American trypanosomiasis was searched for among residents in two geographic microregions of the State of São Paulo: Campos de Itapetininga, in the region of Sorocaba, and Encosta Ocidental da Mantiqueira Paulista, in the region of Campinas. Both areas have in the past been colonized by Triatoma infestans. Campos de Itapetininga remained, until the beginning of the 1970s as a stronghold of this species in the State of São Paulo. Panstrongylus megistus has currently colonized in these areas, now classified as having serological titer profiles characteristic of low endemicity. Transmission of Chagas disease was interrupted earlier in the Encosta Ocidental. Intense exposure to the vector in Campos de Itapetininga can explain the seroreactivity frequencies observed in people born before 1956, aged more than 20 years. Among the residents in this region born between 1972 and 1977, a low positivity rate remains, which might also include cases of congenital transmission. The mean age of seroreagents resident in the Encosta indicates that they must have been born in the 1930s; positivity levels here vary in different municipalities according to their growth in capital goods. After 1984 new criteria were adopted for the use of serology in the Program for the Control of Chagas disease, the detection of seroreagents has not been statistically associated to notification of the occurrence of domestic triatomines in these regions.
Chagas disease; Serological diagnosis; Populational survey; Triatomines
