 Considering the facts that: i IPT of malaria provides substantial protection against anaemia and malaria in school children ii; SP resistance has no significant impact on the prophylactic efficacy iii SP-PQ is safe and as efficacious as SP: the investigators hypothesize that antimalarial IPT with SP and SP-PQ will improve haemoglobin concentration, reduce anaemia prevalence, malaria incidence and parasitaemia, and improve malnutrition and school performance in school-aged children of Congo. 