Reported is an evaluation of 13 years of intervention by the Chagas Disease Control Programme in an endemic area (Montalvania) in the State of Minas Gerais, Brazil. The design used was an epidemiological panel study. The reduction of Trypanosoma cruzi infection rates was estimated from data collected on three separate occasions: a serological survey in 1975-80, a quasi-experimental study in 1987, and the present investigation. A random sample of 156 households was selected and blood samples were collected from 653 inhabitants. The data routinely collected by the control programme were analysed to correlate the results with the incidence of T. cruzi. The overall prevalence of infection was 2.3%; however, no participant under 14 years of age was found to have a positive serological test. The total reduction in T. cruzi infection rates in this area from the start of the programme's activities was estimated to be 83.5%. Cross-sectional comparisons for the age groups 2-6 years and 7-14 years indicated a 100% reduction in T. cruzi incidence rates; but cohort comparisons showed that 100% reduction was achieved only for the 2-6-years age group.
PIP: The Chagas Disease Control Program in Brazil utilizes house spraying with insecticide to control the Triatoma bug population (the intermediate host of Trypanosoma cruzi). Serologic evaluations of selected cohorts have shown a reduction of T. cruzi infection among those born after the start of the national program. This article reports on an evaluation of the Chagas Disease Control Program in Montalvania (State of Minas Gerais), Brazil, conducted in 1995 after 13 years of interventions. Blood samples collected from 653 persons from 156 households revealed a prevalence of T. cruzi infection of 2.3%--an 83.5% reduction since 1987. Seroprevalences were zero in 1995 in the 1-6 and 7-14 year age groups, indicating an interruption in disease transmission. A significant reduction was also recorded in the age group 15-29 years. An earlier evaluation in this area had concluded that 5 years of interventions were not sufficient to produce changes in infection rates. The high proportion of mud houses with dirt floors and tile roofs--ideal conditions for triatomine colonization--indicates a need for continuing active and passive surveillance in this area.