Figure 2: Results of the assay of 258 serum samples from human, collected in the suburban population of Querétaro city (Mexico) by enzyme-linked immunosorbent assay using the Fe-SODe by T. cruzi, as antigen at a dilution of 1/100. The mean and standard deviation of the optical densities of the control sera were used to calculate the cut-off value (mean × 3_standard deviation).