Characterization of Human Immune Signatures to Zoonotic Virus Exposure in Cambodia (Camzoo)

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.

Study Overview

• Status: Recruiting
• Conditions: Immunity, Humoral
• Intervention / Treatment: Procedure: Whole blood collection

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.

• Study Type: Observational
• Enrollment (Estimated): 400

Contacts and Locations

• Study Contact: Name: Chanthap Lon, MD; Phone Number: 85512976799; Email: lonc@icercambodia.org

Study Locations

• Cambodia
  • Battambang, Cambodia
    • Recruiting
    • Communicable Disease Control Department
    • Contact: Seng Heng, MD; Phone Number: 88512852782; Email: senghengmoh@gmail.com
  • Kampong Thom, Cambodia
    • Recruiting
    • Communicable Disease Control Department
    • Contact: Seng Heng, MD; Phone Number: 88512852782; Email: senghengmoh@gmail.com
  • Kampot, Cambodia
    • Recruiting
    • Communicable Disease Control Department
    • Contact: Seng Heng, MD; Phone Number: 88512852782; Email: senghengmoh@gmail.com
  • Stung Treng, Cambodia
    • Recruiting
    • Communicable Disease Control Department
    • Contact: Seng Heng, MD; Phone Number: 88512852782; Email: senghengmoh@gmail.com
  • Takeo, Cambodia
    • Recruiting
    • Communicable Disease Control Department
    • Contact: Seng Heng, MD; Phone Number: 88512852782; Email: senghengmoh@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Healthy adults aged 18 to 65 years who handle suspected infected animals or their excreta, or living within 5 km of animal reservoirs, in Cambodia (n=160 to 320).

Description

Inclusion Criteria:

1. Capacity to provide informed consent.
2. Adult aged 18-65 years.

3. Have interaction with suspected infected animals within the last 2 years, including (but not limited to) the following risk factors:

   1. Hunting, slaughtering, or consuming suspected infected animals;
   2. Fruit collection, date palm sap harvesting, or tree pruning within agricultural plantations containing bat roosts;
   3. Bat guano farming;
   4. 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);
   5. Living within 5 km of identified animal markets or wild animal habitats identified as likely containing infected animals.
4. Willing to allow biological samples and data to be stored for future research.

Exclusion Criteria:

1. Pregnancy (based on self-reporting).
2. 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).
3. Self-reported symptoms suggestive of acute infection (acute myalgias, arthralgias, headache, retro-orbital pain, dyspnea, rash) within 7 days prior to enrollment.
4. 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.
5. 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.
6. Receipt of blood products, including immunoglobulin products, within 120 days of study enrollment.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Antibody binding activity in plasma samples against known immunodominant zoonotic viral proteins	Measured by binding antibody titer greater than cutoffs established from healthy U.S. donors (3 standard deviations above mean signal intensity) to a panel of either henipaviruses, influenza viruses, or sarbecoviruses	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	Measured by circulating antigen-specific B cells constituting approximately 0.001%-0.005% total PBMCs	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	Measured by isolation of an expected 20 million PBMCs from whole blood samples, yielding approximately 100-500 antigen-specific B cells for single-cell B-cell sequencing (anticipated cell death up to 50% during the isolation and sorting process)	Day 0 and 2 optional visits at least 30 days apart between Day 180-720

Collaborators and Investigators

• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)
• Investigators: Principal Investigator: Christina Yek, MD, NIH/NIAID/Laboratory of Malaria and Vector Research (LMVR); Principal Investigator: Lon Chanthap, MD, Malaria Vector & Research Laboratory (MVRL) International Center of Excellence in Research Cambodia; Principal Investigator: Ly Sovann, MD, MTCM, Cambodian Center for Communicable Disease (CCDC) Ministry of Health, Cambodia

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2024
• Primary Completion (Estimated): October 31, 2027
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: November 6, 2024
• First Submitted That Met QC Criteria: November 6, 2024
• First Posted (Actual): November 8, 2024

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 002014

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Data from this study may be requested from other researchers 5 years following completion of the primary endpoint by contacting the Principal Investigators.
• IPD Sharing Time Frame: 5 years following completion of the primary endpoint
• IPD Sharing Access Criteria: Researchers should contact the Principal Investigators with data requests.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No