Characterization of Skin Immunity to Aedes Aegypti Saliva in Dengue-endemic Participants in Cambodia

Background: Mosquito-borne viruses like dengue cause major illness and death worldwide, particularly in Southeast Asia. When mosquitoes deliver a virus into the skin of humans, they also leave saliva. Researchers want to learn more about skin immunity to mosquito saliva. They hope this will help with future vaccines and treatments for these diseases. Objective: To compare the early and late innate immune response in the skin of Aedes aegypti bitten versus unbitten skin. Eligibility: Healthy people ages 18-45 who live within about 15 km of the study site in Chbar Mon Design: Participants will have 3 visits. The baseline/screening visit will include: Medical and medication history Questions about participants demographic information, mosquito biting risk factors, and responses to mosquito or other insect bites Physical exam Urine sample for some participants Mosquito feeding. A feeding device will be placed on the participant s arm for up to 20 minutes. The insects will feed through a mesh on the bottom of the feeding device. Participants may be given standard treatments for any skin reactions. Blood tests Four skin biopsies taken from bitten and unbitten skin. Local anesthetic will be administered, and a small tool will be used to remove the participant s skin. Participants will have a second visit the next day. They will have a physical exam and blood tests. They will have 1 skin biopsy. Participants will have a final visit about 2 weeks later. They will have a physical exam and blood tests. During the study, participants will be asked to take measures to prevent more mosquito bites.