Although SMA in western Kenya can occur in the presence or absence of high-density parasitaemia (HDP, ≥10,000 parasites/μL), the overall level of concomitant peripheral parasitaemia appears less important in determining anaemia severity than the presence of chronic or repeated infections that precipitously reduce Hb concentrations over time [3,4]. This evidence concerns the gene GSTM1 and anemia (phenotype).