This study is designed to directly address antimalarial PK and pharmacodynamics (PD) objectives in children and pregnant women, the populations most vulnerable to malaria. This study will focus on the pharmacology of artemether-lumefantrine (AL), the most commonly prescribed anti-malarial drug in sub-Saharan Africa and inform specific dosing guidelines for AL treatment of uncomplicated malaria for these populations. Traditionally, studies have focused on non-pregnant adults, largely ignoring the effects of childhood maturation and pregnancy on drug disposition. This gap in research is specified as a top priority by the WorldWide Antimalarial Resistance Network (WWARN), who emphasize the importance of proper PK and PD study in relevant populations to reduce the threat of ACT drug resistance and treatment failure. This study will allow optimization of ACT regimens, especially in the setting of HIV co-infection and inform use of ART, specifically for the nucleoside analogues, in the setting of malaria and ACT, with the goal of reducing toxicity.