Vivir sin Chagas” Project: follow-up of infected patients treated with benznidazol at the city of Añatuya, Santiago del Estero, Argentina

SCHIJMAN AG; GRIPPO V; BISIO M; AYALA V; CALLEJOS R; ELEAN JC; MUJICA H; CONTRERAS A; BENTANCOR ME; LOPEZ C; LAFON S; BURGOS JM; LEVITUS G; LEVIN MJ

Congreso; XX Reunión de la Sociedad Argentina de Protozoología; 2004

Abstract INTRODUCTION: We started a prospective study in Añatuya, an endemic region under surveillance in Argentina. We followed 197 seropositive patients (15-45 years old) with no visceral symptoms, who received benznidazol treatment up to 60 days. METHODS: Patients were analyzed at the begining (t0), at the end of treatment (t1) and at 3, 6, 12, 24 and 36 months post-treatment (t2, t3, t4 t5 and t6, respectively). The serology was followed-up by HAI and ELISA. The parasitemia was measured by PCR, based on T.cruzi- kDNA variable region. We report the evolution of 54 patients who were monitored until t6. RESULTS: The PCR was positive in 72% of blood samples at t0. The cohort (54 patients) was classified ein three groups: G1 (PCR negative in all samples until t6; n=15), G2 (PCR positive only at t0; n=8) and G3 (patients with at least one PCR positive result during the post-treatment follow-up); n=31), we observed a seroconversion of 46.7% and 33.3% in G1 and G2 respectively but no seronegativation was achieved in G3 patients (by HAI test). Fourty eight of the 54 patients (88.9%) showed a decrease of ELISA titers, but no seroconversion was found. DISCUSION: All HAI seronegative cases were PCR negative during the 3 years of follow-up, suggesting that a low parasitic load may lead to a better post-therapy outcome. The post-treatment PCR positive cases are likely due to a capacity of the drug to reach amastigote nests in hidden reservoires. These results point to the neccesity to improve the available therapeutic regimens and to develop new drugs for etiological treatment of undeterminate or chronic Chagas disease patients.