[Longitudinal study and specific chemotherapy in children with chronic Chagas' disease, residing in a low endemicity area of Argentina].

Clinical and epidemiological results of 95 treated and untreated chronic chagasic children, with an up to 24 years follow-up period are presented. This population studied in the 1/14 age bracket, residing in Santa Fe city, Argentina, was diagnosed through Chagas-specific conventional serologic reactions. Clinical examination was supplemented with electrocardiogram, chest X-rays, and blood and urine tests for evaluating hepatic function. The drugs employed were nifurtimox or benznidazole. In post treatment period xenodiagnosis was made in 33 patients. Regarding Trypanosoma cruzi transmission, the studied individuals presented multi-risk antecedents: vectorial, congenital and/or blood transfusion. Among 24 untreated children 14 were controlled during 8/24 years: all this patients maintained the initial antibody concentration and clinical status. From 71 treated patients 49 were followed-up 4/24 years: 14 remained positive, 6 presented dubious results, and 29 showed final non-reactive results. 9 of this presented sometimes oscilating results. In 1/6 age bracket children, the serology turned negative after 3.5 years (median) once the treatment was finished, while patients treated in the 7/14 age bracket, the median of negativization was 8 years. 3.8% did not tolerate the drug. None of the groups changed their clinical condition. The untreated children did not change the serology. The percentage of treated children presenting negative serological results decrease according to the age when treatment was given: 75% became negative when treated at < or =4 years old and 43% when treated at > or =9 years old.