The purpose of this study is to analyze the influence of polymorphisms of the genes CLDN-1 (Claudina-1), LGALS3 (Lectin galactoside-binding soluble 3), SOCS3 (Suppressor of cytokine signaling 3), IL-28B (interleukin-28B), CCL5 (Chemokine C-C ligand 5) in the determination of clinical forms and in the percentage of cardiac fibrosis in patients with Chagas disease.