ABSTRACT
In the month of July 1999 and 2000 we studied the presence of Trypanosoma cruzi antibodies in residents of 17 isolated rural communities of "Monte Impenetrable", in Chaco Province. This area has 3,000 km2 inhabited by about 3,000 person and presents all the conditions for the development of Chagas disease. A total of 344 blood samples were analysed for Chagas disease. All samples, stored with SEROKIT, were tested with indirect hemagglutination test, enzyme-linked immunosorbent assay and particle agglutination test. Samples reactive for two assays were considered positive. Serological evidence of human T. cruzi infection was demonstrated in 183 (53.50%) out of 344 individuals. In the 1-15 years age group the percentage of positivity was 45.83% and in the 1-5 years age group 53.85%. a) General infection prevalence in these rural communities was 7 times higher than the national average estimated rate (7.20%). b) Prevalence in the 1-15 years age group was 25 times higher in relation to that found in residents of rural areas under entomology vigilance (1.77%). c) The prevalence in younger than five years old indicated the absence of vectorial control. The Tobas communities presented higher prevalence than Criollos, although the risk factors to acquire the disease were similar in both populational groups. These findings show the urgency of public health policies and sanitary decisions, specially in these zones of the country