Characterization of Human Immune Signatures to Zoonotic Virus Exposure in Cambodia

Overview

This is a biospecimen procurement protocol to characterize the immune response to zoonotic virus exposure in healthy adult humans aged 18 to 65 years with high-risk exposure to animals or their excreta (e.g., guano farming and wet markets), or living within 5 km of animal habitats (e.g., bat caves and bat roosts) in Cambodia.

Detailed description

This is a biospecimen procurement protocol to characterize immune signatures to zoonotic virus exposure in healthy adult humans aged 18 to 65 years who handle suspected infected animals or their excreta, or living within 5 km of animal reservoirs, in Cambodia.

The primary study objective is to characterize immunity to zoonotic viruses, specifically H5N1. To meet this objective, when possible, individuals with the highest likelihood of prior exposure to the viruses of interest (Nipahvirus, bCoVs, H5N1) will be screened for study inclusion. These high-exposure risk behaviors include direct handling of known or suspected infected animals or their excreta. If insufficient individuals meeting these criteria are found, then sampling will include individuals with lower risk exposures, including living or working in areas proximal to (within 5 km of) animal habitats.

All human subjects research activities will be conducted by study personnel within the International Center of Excellence in Research Cambodia, Cambodian CCDC, and the Forestry Administration of the Royal Government of Cambodia. NIH investigators are involved in study design, implementation, analysis of coded samples and data, and writing and dissemination of reports of study results. Although they may support Cambodian investigators in monitoring/oversight capacities, NIH investigators will not be engaged in human subjects research.

Interventions

• Procedure Whole blood collection
  30 mL at Day 0 with optional visits for up to 2 additional whole blood collections at least 30 days apart

Primary outcome measures

• Antibody binding activity in plasma samples against known immunodominant zoonotic viral proteins [Time frame: Day 0 and 2 optional visits at least 30 days apart between Day 180-720]
• Neutralizing activity of plasma samples against known immunodominant zoonotic viral proteins [Time frame: Day 0 and 2 optional visits at least 30 days apart between Day 180-720]
• Isolate viral antigen-specific B cells for phenotyping and immunoglobulin sequencing [Time frame: Day 0 and 2 optional visits at least 30 days apart between Day 180-720]

Eligibility criteria

Inclusion criteria

• Capacity to provide informed consent.
• Adult aged 18-65 years.
• Have interaction with suspected infected animals within the last 2 years, including (but not limited to) the following risk factors:

• Hunting, slaughtering, or consuming suspected infected animals;
• Fruit collection, date palm sap harvesting, or tree pruning within agricultural plantations containing bat roosts;
• Bat guano farming;
• Ancillary work in live animal markets or wild animal habitats identified as likely containing infected animals (e.g., provision of cleaning, transportation, or tourism services);
• Living within 5 km of identified animal markets or wild animal habitats identified as likely containing infected animals.
• Willing to allow biological samples and data to be stored for future research.

Exclusion criteria

• Pregnancy (based on self-reporting).
• Any underlying, chronic, or current medical condition that, in the opinion of the investigator, would interfere with participation in the study (e.g., inability or great difficulty in drawing blood, known anemia).
• Self-reported symptoms suggestive of acute infection (acute myalgias, arthralgias, headache, retro-orbital pain, dyspnea, rash) within 7 days prior to enrollment.
• Signs suggestive of acute infection (fever, defined as internal temperature >38°C; hypoxemia, defined as peripheral oxygen saturation of <90%; hypotension, defined as systolic blood pressure <90 mm Hg or diastolic blood pressure <50 mm Hg) present at screening.
• Self-reported diagnosis of immune deficiency, including HIV infection, chronic corticosteroid use (≥10 mg prednisone dose or its equivalent for a continuous period of ≥30 days within the last 1 year), ongoing or prior (within the last 10 years) receipt of chemotherapy or immunotherapy, or current hematological malignancy.
• Receipt of blood products, including immunoglobulin products, within 120 days of study enrollment.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Observational model

Ecologic or community

Study locations

Cambodia · 5 centers

• Communicable Disease Control Department — Battambang
• Communicable Disease Control Department — Kampong Thom
• Communicable Disease Control Department — Kampot
• Communicable Disease Control Department — Stung Treng
• Communicable Disease Control Department — Takeo

Identifiers

NCT: NCT06680843 · 002014

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗