Anaemia had a much greater effect on day 0 WBC count in patients with vivax malaria compared to those with falciparum malaria, with a 36.4% lower WBC count observed in vivax patients with severe anaemia (Hb < 7 g/dL) as compared to those with a normal haemoglobin (Hb ≥ 10 g/dL). This evidence concerns the gene GSTM1 and anemia (phenotype).