Sample size Sample size is calculated based on the differences of malaria incidence between before and after intervention in each arm. Baseline incidence is determined from positive-malaria children in monthly cohort between MST1 and MST3 in arm 1 or MST1 until MST3 in arm 2. Malaria incidence in the arm 2 is assumed to remains constant at 0.7 new cases/person-year during study(unpublished data). The impact of the intervention arm is expected to reduce malaria incidence maximum by 50% to 0.35 new cases/person-year. With the proposed sample size of 70 children per arm, we will have a power of 82% to detect a significant difference. Considering a 10% of loss to follow-up and a design effect of cluster-randomized trial 1.5, we will recruit 115 children per arm.