title: Clinical follow-up of responses to treatment with benznidazol in Amazon: a cohort study of acute Chagas disease.
abstract: A total of 179 individuals with acute Chagas disease mainly transmitted by oral source, from Pará and Amapá State, Amazonian, Brazil were included during the period from 1988 to 2005. Blood samples were used to survey peripheral blood for T. cruzi hemoparasites by quantitative buffy coat (QBC), indirect xenodiagnosis, blood culture and serology to detection of total IgM and anti-T. cruzi IgG antibodies by indirect immunofluorescence assay (IFA) and indirect hemagglutination assay (HA). All assays were performed pre-treatment (0 days) and repeated 35 (±7) and 68 (±6) days after the initiation of treatment with benznidazol and every 6 months while remained seropositive. The endpoint of collection was performed in 2005. Total medium period of follow-up per person was 5.6 years. Also, a blood sample was collected from 72 randomly chosen treated patients to perform polimerase chain reaction (PCR) method. Proportions of subjects with negative or positive serology according to the number of years after treatment were compared. In the endpoint of follow-up we found 47 patients (26.7%) serologically negative, therefore considered cured and 5 (2.7%) exhibited mild cardiac Chagas disease. Other 132 patients had persistent positive serologic tests. The PCR carried out in 72 individuals was positive in 9.8%. Added, there was evidence of therapeutic failure immediately following treatment, as demonstrated by xenodiagnosis and blood culture methods in 2.3% and 3.5% of cases, respectively. There was a strong evidence of antibody clearing in the fourth year after treatment and continuous decrease of antibody titers. Authors suggest that control programs should apply operational researches with new drug interventions four years after the acute phase for those treated patients with persistently positive serology.
authors.affiliation: Clinical epidemiologic Department of Evandro Chagas Institute-SOAMU-IEC-Secretaria de Vigilância em Saúde/Brazil Ministery Health-SVS/MS, Belém, Pará, Brazil. ayece@iec.pa.gov.br
authors.forename: Ana Yecê das Neves
authors.initials: AY
authors.lastname: Pinto
authors.forename: Vera da Costa
authors.initials: Vda C
authors.lastname: Valente
authors.forename: José Rodrigues
authors.initials: JR
authors.lastname: Coura
authors.forename: Sebastião Aldo da Silva
authors.initials: SA
authors.lastname: Valente
authors.forename: Angela Cristina Veríssimo
authors.initials: AC
authors.lastname: Junqueira
authors.forename: Laura Cristina
authors.initials: LC
authors.lastname: Santos
authors.forename: Alberto Gomes
authors.initials: AG
authors.lastname: Ferreira
authors.forename: Roberto Cavalleiro
authors.initials: RC
authors.lastname: de Macedo
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology; D001938:Brazil; D002598:Chagas Cardiomyopathy / Q000175:diagnosis; D014355:Chagas Disease / Q000175:diagnosis / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008875:Middle Aged; D009593:Nitroimidazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D019371:Topography, Medical; D016896:Treatment Outcome; D014344:Trypanocidal Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D014349:Trypanosoma cruzi / Q000235:genetics / Q000276:immunology; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D009593:Nitroimidazoles; D014344:Trypanocidal Agents; C009999:benzonidazole