Characterization of Skin Immunity to Aedes Aegypti Saliva in Dengue-endemic Participants in Cambodia
Condition: Vector Borne Diseases
MeSH terms: Vector Borne Diseases
Intervention: Mosquito Feeding
Intervention description: Mosquito feedings will be conducted with Aedes aegypti colonies raised at the CNM (National Malaria Center) Malaria and Vector Research Laboratory (MVRL), an established state of the art insectaries for mosquitoes was built in 2014 to ACL2 (arthropodcontainment level 2)-level specifications.
Phase: Phase 1
Study type: Interventional
Primary purpose: Basic Science
Intervention model: Single Group Assignment
Intervention model description: Participants were all exposed to 5 uninfected Aedes aegypti mosquitos on their forearm. Biopsies were taken of bitten and unbitten skin.
Masking: None (Open Label)
Enrollment: 42.0
Sex: All
Minimum age: 18 Years
Maximum age: 45 Years
Healthy volunteers: No
Keywords: Vector-Borne Diseases; Immune Response; Mosquito Feeding; Arbovirus; Southeast Asia

Summary:

      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.
    

Eligibility criteria:

        -  INCLUSION CRITERIA:

        In order to be eligible to participate in this study, an individual must meet all of the
        following criteria:

        -Provision of signed and dated informed consent form

          -  Stated willingness to comply with all study procedures and availability for the
             duration of the study

          -  Male or female, aged 18 - 45 years

          -  Live within approximately 15 km of study site

          -  In good general health as evidenced by medical history

          -  Willing to allow biological samples to be stored for future research.

          -  A female is eligible for this study if she meets 1 of the following:

               -  Of non-childbearing potential (i.e., women who have had a hysterectomy or tubal

        ligation or are postmenopausal, as defined by no menses in >=1 year).

        --Of childbearing potential but has negative urine pregnancy test on Day 0

          -  Agrees to not use scented lotions, deodorants, or topical creams on each feeding day.

          -  Agrees to not take aspirin or any other NSAID (ex. ibuprofen) within 7 days of a
             biopsy.

          -  Agrees to not use oral or topical antihistamines or steroid creams or ointments
             throughout the

        study without prior permission of Principal Investigator (PI).

        EXCLUSION CRITERIA:

        -Any underlying or current medical condition that, in the opinion of the investigator,
        would

        interfere with participation in the study.

        -History of severe allergic reaction (including to mosquito or other insect bites) with
        generalized

        urticaria, angioedema, anaphylaxis, anaphylactoid reaction or any other reaction described
        by

        the participant and deemed severe by the PI.

          -  Self-reported or known history of alcoholism or drug abuse within 6 months prior to
             enrollment

          -  Self-reported or known history of psychiatric or psychological issues that require
             treatment and

        are deemed by the PI to be a contraindication to protocol participation.

        -Any use of medications that affect blood clotting within 3 months or history of abnormal
        blood

        clotting

        -History of significant scarring such as keloids after previous biopsies, lacerations,
        abrasions,

        surgeries, or other skin procedures (e.g., cosmetic piercings) that are deemed by the PI to
        be a

        contraindication to protocol participation.

        -Pregnant or breastfeeding.