Efficacy of Artesunate-Mefloquine Combination Therapy in Trat Province, Thailand

Inclusion Criteria: 1. Age 5 to 70 years inclusive. If aged \< 18 years the subject must have a parent or guardian in attendance. 2. Asexual stages of P. falciparum parasites in a thick or thin blood film with no other visible plasmodial species. 3. Willing to give informed consent. Parents or guardians of children and adolescents must agree to give informed consent. Assent is necessary in addition to parental informed consent. 4. Able to tolerate oral therapy. 5. Willing to attend follow-up appointments and undergo study procedures. Exclusion Criteria: 1. History of anti-malarial drug use within the past two weeks or mefloquine (MQ) use within 4 weeks. 2. Bleeding tendency (by history or based on medical records). 3. Severe/complicated malaria as determined by the investigator (coma or seizures, pulmonary edema, shock, renal failure, jaundice, severe anemia, spontaneous bleeding, hyperparasitemia (\>5% RBCs infected), or prostration). 4. History of allergy to or intolerance of study medications. 5. Mixed malaria infection by Giemsa stain. 6. Any other condition that in the opinion of the study investigator warrants parenteral antimalarial treatment. 7. Pregnant woman or nursing mother