In addition to active case detection through home visits, parents and care-givers of the subjects will be advised of signs and symptom of illness and instructed to bring sick children to the on-site clinic for assessment and treatment. Study clinical staff will be available round-the clock for the entire duration of the trial. During these unscheduled visits malaria smears, blood paper filter and hemoglobin will be done in case of signs or symptoms compatible with clinical malaria.