GSTM1 and anemia (phenotype): Levels of clinical malaria and anaemia in this region has been previously described [25] but for the subset of people in this study mild anaemia (Hb ≤ 11.0 g/dl) was detected in 52.7% of individuals, moderate anaemia (Hb ≤ 8.0 g/dl) was seen in 8.4% and fever (temperature ≥ 37.5°C) was observed in 14.3% of cases.