The investigators' Hypothesis is that "The correct timing of gametocytocidal drug in combination with an effective Artemisinin Combination Therapy can limit the infectiousness of malaria-infected individuals to less than one week after initiation of treatment"

Global malaria elimination is back on the agenda, gametocytocidal drugs such as primaquine are currently advocated for use in the interventions that aim to interrupt malaria transmission and hence elimination. Mature gametocytes are responsible for malaria transmission. Artemisinin based combination therapies (ACTs) has limited effect on the young gametocytes. Primaquine is able to clear mature gametocytes that remain after treatment with ACTs. Complete clearance of mature gametocytes will depend on the ideal time primaquine is given after ACT. It is important therefore that is administered at optimal time in order to have significant impact on clearing gametocytes to interrupt malaria transmission. An additional consideration is operational administration of Primaquine and compliance both of which are likely to be enhanced if the drug is administered on the day of diagnosis.

In this study, the investigators aim to determine optimal timing of primaquine administration in addition to ACT by comparing administration on day 0 with administration on day 2.

The investigators' primary end points are gametocyte prevalence and density by microscopy and Quantitative Nucleic Acid Based Amplification (QT-NASBA) on day 14, which will be compared between the two primaquine treatment arms.

Inclusion Criteria:

• Age 3 years - 17 years
• Residents of research area
• Willingness to come for complete scheduled follow-up.
• Uncomplicated malaria with P. falciparum mono-infection
• Axillary temperature > 37.5°C and < 39.5°C, or history of fever in previous 48 hours.
• No history of adverse reactions to study medication
• Understanding of the procedures of the study by parent or guardian and willing to participate by signing written informed consent forms

Exclusion Criteria:

• Haemoglobin below 9g/dl
• Inability to take drugs orally
• Known hypersensitivity to any of the drugs given
• Reported treatment with antimalarial chemotherapy in the past 2 weeks
• Evidence of chronic disease or acute infection other than malaria
• Domicile outside the study area
• Signs of severe malaria( such as respiratory distress, altered consciousness deep breathing, anaemia)
• Participating in other malaria studies conducted in the region
• Mixed malaria parasite species infection
• Positive pregnant test by Urine (UPT) if participant is female aged above 12 years
• G6PD deficient using the fluorescence spot test