Follow up study during and after two month regimen of Benznidazole in pediatric chronic Chagas patients in Bolivia

Abstract

Introduction: Chagas disease is a parasitic infection endemic in Latin America caused by Trypanosoma cruzi. In Bolivia, vector control activity by the National Program for Chagas has greatly decreased the number of natural infections since 2006. The program began a treatment regimen of Benznidazole (BNZ) (5mg/kg/day) for 2 months in seropositive children aged 4-15 years living in certified vector controlled areas. Purpose: Evaluate efficacy and complications of the standard regimen of BNZ. Method: One-year follow-up study including blood sampling seven times before and after the treatment. Serology, conventional PCR, and real-time qPCR with dual-labeled TaqMan probes were performed. Serum levels of Th1/Th2/Th17 cytokines were determined using a cytometric bead array. Results: 73 out of 100 seropositive children tested by the school screening complied with the BNZ treatment, with 3 persons interrupted due to side effects. qPCR revealed that 32 children out of 73 showed persistence of low but substantial amounts of T. cruzi DNA indicating treatment failure. When we observed a series of cytokines, IL-17A levels were significantly higher in the seropositive group before the treatment than seronegative, and decreased one year after the treatment. IL-17A levels appear to be associated with the efficacy of the treatment. Conclusion: With no natural infection observed in the target areas, persistent presence of parasite DNA after treatment suggests a treatment failure. IL-17A may potentially be a biomarker for assessment of the treatment. Long term follow up program for the treated children is necessary.