2024-12-11-世界卫生组织-Influenza_at_the_human-animal_interface_summary_and_assessment,_12_December_2024_7页_271kb

Influenza at the Human-Animal Interface Summary

1. Current Situation

• New Human Cases (2 Nov to 12 Dec 2024):
  • Influenza A(H5) virus detected in 16 humans.
  • Influenza A(H9N2) virus detected in 9 humans.
• Animal Infections:
  • High pathogenicity avian influenza (HPAI) continues to be reported in poultry and non-poultry animals, primarily in the Americas, Asia, and Europe.
  • Infections in non-human mammals (e.g., marine/land mammals) also reported.
• Country-Specific Updates:
  • USA: 14 cases of A(H5), mostly mild and associated with dairy cattle exposure.
  • Canada: One teenager infected with A(H5N1), severe case with ARDS, but no evidence of human-to-human transmission.
  • Viet Nam: One case of A(H5) in an 18-year-old male with comorbidities; fully recovered.

2. Risk Assessment

• Overall Public Health Risk:

  • The current risk from known influenza viruses at human-animal interface remains low. Sustained human-to-human transmission is unlikely.
  • Additional human cases are expected but not surprising, primarily linked to direct/indirect exposure to infected animals or contaminated environments.
  • Minimal impact on public health if additional cases occur.

• Risk Breakdown by Subtype:

  • A(H5):
    1. Cases mostly involve exposure to infected poultry/cattle or contaminated environments.
    2. No sustained human-to-human transmission observed since 2007.
    3. International spread via travelers is considered unlikely for causing widespread community transmission.
  • A(H9N2):
    • Similar risk profile to A(H5): cases linked to poultry exposure, mild illness predominates, no sustained transmission, and low public health risk.

3. Risk Management Recommendations

Surveillance & Investigations

• Global strategic surveillance for influenza virus evolution in animals and humans is essential.
• Enhanced surveillance in affected regions, systematic follow-up of suspected human cases, and collaboration with animal health sectors are recommended.
• Monitor domestic/wild birds, livestock, and report HPAI cases in all animal species to WHO/OIE.
• Public health labs should characterize animal-origin viruses.

Notifying WHO & Virus Sharing

• All cases of new influenza subtypes must be reported under International Health Regulations (IHR, 2005).
• Publicly share influenza viruses with pandemic potential through WHO’s Pandemic Influenza Preparedness (PIP) framework.
• Use risk-assessment tools like WHO’s Tool for Influenza Pandemic Risk Assessment (TIPRA) to evaluate transmission potential.

Risk Reduction for the Public

• Avoid contact with sick/dead animals, especially poultry and wild birds.
• Cook eggs and poultry meat thoroughly; avoid raw milk and ensure food hygiene practices.

Travelers & Trade

• WHO advises travelers avoid farms and live animal markets in affected regions.
• Trade restrictions are not recommended per WHO; refer to OIE guidelines for safer animal product trade.

1. Footnotes:
   • 1 Summary and assessment covers confirmed cases up to 12 December 2024.
   • 14 WHO Case Definitions for Notifiable Influenza Infections.
   • 16 WHO Pandemic Influenza Preparedness Framework (2017).