The subset of 1,000 patients will be intensively followed-up. These patients will have haematology (Hb and full blood counts (RBC, WBC and differential count)) and standard biochemistry (BUN, Creatinine, ALT/AST, Bilirubine, electrolytes (K+ and Cl-)) undertaken at Day 1 (before drug administration), Day 3 (3-4 hours after the last dose of treatment), and Day 7. If the results are abnormal and clinically relevant, the blood examination will be repeated until normalization. In all the 1000 patients, a plasma sample will be collected on Day 1 (before drug administration), twice on Day 3 (i.e. before and 3-4 hours after the last drug administration) as well as on Day 7 to assess plasma PQ concentration. From such blood drawings and before centrifugation, three drops of whole blood will be spotted on filter papers. These filter papers will be utilized to determine whole blood piperaquine concentration with the Dry Blood Spot methodology (if a validated analytical method for such determination will be settled up at the time of the study course). ECGs will be undertaken on Day 1 (before drug administration), twice on Day 3 (i.e. before and 3-4 hours after the last drug administration) as well as on Day 7 (ECG on Day 1 and Day 3 after last drug administration will be collected in triplicate); safety information will be collected at all these visits.