Positron Emission Tomography and Organ-Specific Changes in Participants Co-Enrolled in NIH Studies of Plasmodium Vivax Controlled Human Malaria Infection

Background: Malaria is a serious disease caused by parasites spread by mosquitoes. To better diagnose and treat malaria, researchers need to learn more about where the parasites go when they enter a person's body. They want to see if they can locate the malaria parasites in the body using imaging scans. Objective: To learn whether imaging scans can locate parasites in people with malaria. Eligibility: Healthy people aged 18 to 54 years. They must be enrolled in protocol IRB001970 or IRB002627 for controlled malaria infection. Design: Participants will be screened. They will have blood drawn and a physical exam, including an abdominal exam to check the size of their spleen. Participants for this study will have 2 or 3 positron emission tomography/computed tomography (PET/CT) scans: The first will be about 3 days before they are deliberately infected with malaria for a different study. The second will be about 13 days later, while they have the disease. The third scan is optional; it will be done about 3 and 1/2 weeks after the second scan. For each scan, participants will receive a radioactive tracer called fluorodeoxyglucose (FDG). FDG will be injected through a tube inserted into a vein. They will lie on a table that slides through a doughnut-shaped machine. PET/CT uses x-rays to create images of the inside of the body. All participants will have a follow-up visit about 3 and 1/2 weeks after the second scan. The blood draw and physical exam will be repeated. This visit may be combined with the third scan for those who choose it.

* INCLUSION CRITERIA In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Aged \>=18 and \=45 years plus no menses for 12 consecutive months without an alternative medical cause). * Having exclusive same-sex relations or committed longstanding abstinence due to a serious life choice. * Having an exclusive male partner who has undergone vasectomy at least 4 months prior. 6. Participants need to have established medical care with a primary care doctor or be willing to establish care in case medically relevant findings on their imaging require follow-up. EXCLUSION CRITERIA An individual who meets any of the following criteria will be excluded from participation in this study: 1. Pregnancy or lactation. 2. History of splenectomy. 3. History of diabetes or poorly controlled blood sugar, in the judgement of the investigators, would prevent completion of FDG-PET/CT scan. 4. Currently undergoing therapy with drugs that, in the judgment of the investigators, may interfere with biodistribution of FDG (e.g., insulin that cannot be held or metformin that cannot be stopped for 48 hours prior to each FDG-PET/CT.). 5. Any other finding that, in the judgment of the investigator, would interfere with, or serve as a contraindication to, protocol adherence, assessment of safety, or a participant s ability to give informed consent, or increase the risk of having an adverse outcome from participating in the study. Co-enrollment guidelines: Co-enrollment in other trials is restricted, other than enrollment on the LMIV CHMI trials described above and NIH protocol 17I0122, NIAID Centralized Sequencing Protocol. Study staff should be notified of co-enrollment on any other protocol as it may require the approval of the principal investigator.