Epidemiology of Chagas disease in Chile. Frequency of human Trypanosoma cruzi infection by age groups and regions

: Chagas' disease is endemic in rural-periurban sections of the northern half of Chile which includes the first seven political-administrative regions of the country (18 degrees 30'-34 degrees 36' South lat.). Data concerning to the results of an indirect hemagglutination test for Chagas' disease performed to 15,418 rural-periurban and 45,119 urban inhabitants fron the chagasic endemic regions are presented. Migrations from rural-periurban to urban areas have contributed to the dissemination of Trypanosoma cruzi infection. General rates of infection for rural-periurban (r-p) and urban (u) sections were 16.7% and 1.9% respectively. The higher prevalence rates were detected in Region III with 27.2% (r-p) and 3.9 (u) and Region IV with 24.7% (r-p) and 3.5% (u), while the lower prevalence rates corresponded to Region VI with 7.0% (r-p) and 0.8% (u). Serological positivity increased parallelly with age in all regions.