GSTM1 and anemia (phenotype): Although no clear differences in the median hemoglobin level of VL-malaria co-infected patients (7.5 g/dl) versus the mono-infected VL patients (8.2 g/dl) could be detected, the proportion of patients with severe anemia (Hb <5.3 g/dl) was significantly higher among cases (15.7%) than among controls (5.2%) (OR: 3.44; 95% CI: 1.68-7.02).