During the follow-up period, all patients presenting to the clinic with a new episode of fever will undergo standard evaluation (history, physical examination and Giemsa-stained blood smear) for the diagnosis of malaria. Children diagnosed with uncomplicated malaria will be treated with AL and children diagnosed with complicated malaria will be treated with quinine in accordance with national guidelines. Response to antimalarial therapy will be assessed using standardized guidelines. All AL treatment failures occurring within 14 days of diagnosis will be treated with quinine in accordance with national guidelines. In the event that a patient fails quinine therapy, therapy will be repeated with quinine plus clindamycin. Patients with complicated malaria who have contraindications to giving quinine will be treated with parenteral artesunate. All episodes diagnosed more than 14 days after a previous episode will be considered new episodes for treatment purposes. After two years of age, patients with uncomplicated malaria will have follow up visits on the days Antimalarial drugs are administered only (Day 0, 1, and 2). Routine assessments will be performed in the study clinic approximately every 30 days. Routine assessments will include review of study protocol with parents/guardians of study participants, assessment for any outside medical care, assessment for adherence to assigned chemopreventive therapy, a focused history and physical examination and routine blood smears for the detection of asymptomatic parasitemia. Routine phlebotomy will be performed approximately every 120 days for all study participants for CBC, glucose and ALT measurements.