2.2.2. Blood collection on admission On admission blood will be collected for parasite count (thin and thick films stained by Field's method), CBC, and routine biochemistry. An additional 20 ml of blood will be collected in a sterile heparinised tube for parasite culture and cryopreservation, and 2 ml for assessment of drug levels (artesunate and mefloquine). The maximum volume taken from children < 10yrs is 10mL.