GSTM1 and malaria: A venous blood sample (3 mL), for Hb testing, determination of iron indices (serum – for ferritin, C reactive protein (CRP) and Arabinogalactan protein (AGP)), thick and thin malaria slides for malaria microscopy testing (to be conducted at the completion of the trial) and filter paper for plasmodium PCR, is collected from the child.