2022-10-04-世界卫生组织-Influenza_at_the_human-animal_interface_summary_and_assessment,_5_October_2022_5页_244kb

Influenza at the Human-Animal Interface Summary (31 August to 5 October 2022)

Core Content Overview

This document provides a summary and risk assessment of influenza viruses at the human-animal interface during the period from 31 August to 5 October 2022. It covers avian influenza A(H5) and A(H10N3) viruses, as well as swine influenza A(H1N1) variant viruses, and outlines WHO's risk management recommendations and compliance requirements under the International Health Regulations (IHR, 2005).

Human Infections Reported

• Avian Influenza A(H5N6): One case reported in China, involving a 3-year-old boy from Guangxi with severe pneumonia. He had exposure to backyard poultry, and no environmental samples were positive for the virus. No family members showed symptoms.
• Avian Influenza A(H10N3): One case reported in China, involving a 33-year-old male from Zhejiang with pneumonia. He had exposure to backyard poultry, and no further cases were found among close contacts or family members.
• Swine Influenza A(H1N1) variant: One case reported in China, involving a 6-year-old girl from Shaanxi with mild respiratory illness. The source of exposure was unknown.
• Swine Influenza A(H1N2) variant: Three cases reported in the United States (two in Michigan and Wisconsin, and one in Georgia). All were in children under 18, with mild illness. No evidence of human-to-human transmission was found.

Risk Assessment Summary

Avian Influenza A(H5) Viruses

1. Likelihood of additional human cases: High, as these viruses continue to circulate in birds and environments.
2. Human-to-human transmission: Low, based on current evidence; no sustained transmission has been observed.
3. International spread by travelers: Possible, but unlikely to lead to community-level outbreaks due to the low transmissibility among humans.

Avian Influenza A(H10N3) Viruses

1. Likelihood of additional human cases: Moderate, as these viruses have been detected in wild birds and backyard poultry.
2. Human-to-human transmission: Low, with no evidence of sustained transmission.
3. International spread by travelers: Possible, but unlikely to cause further spread without human-to-human transmission.

Swine Influenza Viruses (A(H1N1)v and A(H1N2)v)

1. Likelihood of additional human cases: Moderate to high, depending on the region and exposure to swine.
2. Human-to-human transmission: Low, with no evidence of sustained transmission.
3. International spread by travelers: Possible, but unlikely to lead to community-level outbreaks.

Risk Management Recommendations

• No special traveler screening or restrictions: WHO does not recommend additional measures for travelers due to the current low risk of sustained human-to-human transmission.
• Avoid contact with animals and contaminated surfaces: Travelers should avoid farms, live animal markets, slaughter areas, and contaminated surfaces. Good hand hygiene is advised.
• Avoid contact with sick or dead birds: The public should avoid contact with sick or dead birds, including wild birds, and report any dead birds to local authorities.
• Global surveillance is critical: Continued monitoring of both animal and human influenza viruses is essential to detect any changes in virulence, transmissibility, or epidemiology.
• Collaboration between animal and human health sectors: Integrated surveillance and information sharing are necessary to enhance preparedness and response.
• Compliance with IHR (2005): All new influenza subtypes must be reported to WHO. No evidence of illness is required for notification.
• Virus characterization: Influenza viruses from animals or humans should be fully characterized in WHO reference laboratories to support risk assessment and vaccine development.
• PIP Framework: Member States are expected to share influenza viruses with pandemic potential with the Global Influenza Surveillance and Response System (GISRS) for timely risk evaluation and vaccine development.

Key Information and Resources

• WHO Risk Assessment: The overall public health risk remains unchanged.
• Candidate Vaccine Virus (CVV) selection: Recent WHO consultations have selected CVVs for zoonotic influenza viruses for pandemic preparedness.
• IHR Compliance: New influenza subtypes must be reported to WHO.
• Resources:
  • WHO Human-Animal Interface Web Page
  • WHO Protocol for Investigating Non-Seasonal Influenza
  • WOAH Avian Influenza Web Page
  • FAO Animal Health Page
  • OFFLU Platform for tracking influenza outbreaks.