PQ has previously been used for treating symptomatic patients in the lower Moshi area, the area where the current study will be carried out. The rationale was to reduce post-treatment malaria transmission. The strategy was abandoned to follow national guidelines but no side effects were reported. In addition, PQ was recently used in combination with SP and AS and found to be safe and highly efficacious in clearing all parasite stages. However, there is concern for negative haemolytic side effects that have been reported for the full dose regimen in individuals who are G6PD deficient. Haemolytic side effects are generally self-limiting and, more importantly, are observed in individuals receiving the full dose PQ treatment (0.5 mg/kg, 14 days). Despite these limitations of PQ as full-dose treatment, PQ can also be used to clear gametocytes, after clearing asexual parasites with a different drug or drug-combination. This gametocytocidal treatment requires a single dose of PQ only and is mentioned by the World Health Organization (WHO) as beneficial in areas of low malaria transmission. PQ has a short half-life of 5-6 hours and the single dose of 0.75mg/kg (adults 45mg) is too low to cause haemolytic effects. According to WHO standards, testing for G6PD deficiency is therefore not required.