Multiplicity of infection was not associated with parasite density (OR = 1.0, 95%CI: 0.99–1.00), age (OR: 0.99, 95%CI: 0.97–1.02) or Hb (OR: 1.06, 95%CI: 0.85–1.31), but did appear to be associated with fever (OR: 3.10, 95%CI: 1.83–17.52). This evidence concerns the gene GSTM1 and infection.