 Drugs will be administered to the study children every month from May to October. Field workers and coordinators will visit the participants once a week from May to October. Parents and guardians will be strongly advised to come directly to a health centre if their child develops any symptoms or signs of illness between the field workers weekly home-visits. Passive surveillance will be performed by six medical assistants and twelve nurses based in the health centres in the sub-districts within the district. Malaria clinical attacks will be documented and treatment for malaria and any other illness will be provided free of charge to study participants in all the health centres that are in the catchment area of the selected communities. 