Usefulness of serology for the evaluation of Trypanosoma cruzi transmission in endemic areas of Chagas' disease.

Thirteen communities from 7 Argentinian provinces were selected for the evaluation of serology as an indicator of transmission of Chagas disease. Of the communities appraised, 6 did not have a history of previous treatment with insecticides and 7 had received sporadic or continuous insecticide treatment. The inhabitants of 20% of the houses of each locality were studied by serology. The samples were obtained by finger pricking and 50 microliters of blood were mixed with 15 microliter of 50% glycerine solution in tissue culture media to be assayed by Indirect Hemagglutination and Indirect Immunofluorescence tests. In untreated areas, the prevalence of infection in infants 0-4 years old was 17.5%, reaching to over 22% for the 5-9 year old group, and to 33.3% in 10-14 year old individuals. The prevalence in treated and surveyed areas was 2.6% in 0-4 year old children, 5.4% in 5-9 year old and 6.2% in 10-14 year old youngsters. The differences between both areas were statistically significant (p less than 0.005). This study favors serology as a valid indicator for the evaluation of transmission of Chagas disease in rural areas.