RESUMO
To evaluate the epidemiological situation of Chagas disease infection in the State of Piauí, Brazil, and its relationships with age, gender, blood transfusion and spontaneous abortion, a serological survey was performed. A random sample of 36,399 inhabitants of rural zones was examined between August and December 2002. Chagas disease infection was defined by the indirect immunofluorescence test, with identification of anti-Trypanosoma cruzi antibodies in blood samples collected on filter paper. The total seroprevalence was 1.9%, ranging from 0.1% in children less than five years old to 6.6% in adults over 79 years old. The seroprevalence was significantly higher in women (2.1%), illiterates (4.1%), individuals receiving blood (3.3%) and women with a history of spontaneous abortion (5.4%). Comparison with the national serological survey (1975-1980) showed that there had been a significant reduction in the seroprevalence of Chagas disease infection in the State of Piauí (4.0% to 1.9%), which was indicative of the efficacy of the vector control measures implemented between 1975 and 2002.