Fig. 4

Prevalence of fever (a), anaemia and severe anaemia and haemoglobin concentration (b) for the 6 months–4 years age category, by parasite-density category and site. M month, Y year. Prevalence was calculated as the percentage of children with reported fever/anaemia/severe anaemia in each parasite-density category. The sites are ordered according to increasing values of Plasmodium falciparum prevalence in the first survey