Biomarkers of P. Vivax Relapse

Inclusion Criteria: For P. vivax-infected malaria subjects 1. Are a Thai male or non-pregnant/non-lactating female aged at least 18 years and are able to fluently speak and understand Thai 2. Willingness to participate in the study as evidenced by witnessed, signed informed consent from the subject (written or thumb print) 3. Have P. vivax malaria mono-infection as determined by blood smear, with a parasitemia range of 100-400,000 parasites/microliter 4. Are available to stay in a controlled setting for the first 28 days of this study to minimize exposure to mosquitoes and available for follow-up for anticipated study duration 5. Resides in Sisaket or Ubon Ratchathani Province 6. Are of normal (non-deficient or \>30% activity) G6PD phenotype as defined by WHO 7. Agree to not seek outside medical care prior to contacting the Armed Forces Research Institute of Medical Sciences (AFRIMS) study team if a fever develops during study participation (approximately 180 days), unless emergency medical care is required For healthy control group 1. Are a Thai male or non-pregnant/non-lactating female aged at least 18 years and are able to fluently speak and understand Thai 2. Willingness to participate in the study as evidenced by witnessed, signed informed consent from the subject (written or thumb print) 3. Free of malaria and other significant health problems as established by medical history, laboratory assessment and clinical examination by clinical investigator 4. Normal (non-deficient or \> 30% activity) G6PD phenotype as defined by World Health Organization (WHO) 5. Resides in Sisaket or Ubon Ratchathani Province Exclusion Criteria: For P. vivax-infected malaria subjects 1. Have an allergic reaction to artesunate or primaquine 2. History of anti-malarial drug use within the past 28 days 3. Have symptoms of severe malaria needing urgent treatment, such as serious vomiting, unable to eat or drink, prostration, or other signs/symptoms of concern to the doctors 4. Are a pregnant or lactating female, or female of childbearing age, up to 50 years of age or otherwise individually assessed for childbearing potential, who does not agree to use an acceptable form of contraception (e.g. pills or injectable) during this study and for 1 month after study completion 5. Chronic use of medications known to cause drug interactions with primaquine or CYP450 2D6 (selective serotonin reuptake inhibitors (SSRIs) or other medications used for psychological conditions, as well as antihistamines, antihypertensives, codeine) 6. Any other significant finding that in the opinion of the investigator would increase the risk of having an adverse outcome from participating in this study For healthy control group 1. Has history of malaria infection in the past 10 years 2. Positive for any Plasmodium species by blood smear or PCR at time of screening 3. Pregnant or lactating female 4. G6PD deficient as defined by WHO 5. Any other significant finding that in the opinion of the investigator would increase the risk of compromising the validity of being a control (eg., chronic daily chewing of betel nut (may impact saliva assays) or menstruating females (whereby urine collections may have blood and impact assay results), etc.