If parasites reappear in 50% or more of at least 40 children in one of the treatment groups this treatment arm should be terminated. During the study parents are recommended to bring the child to Bandim Health Centre in case of any illness. Participating children will be examined and treated free of charge. Following the recommendations of the national Malaria Programme sulfadoxine/pyrimethamine will be used for re-treatment of children in case of recrudescence.