2016-02-24-世界卫生组织-Influenza_at_the_human-animal_interface_summary_and_assessment,_25_February_2016_8页_341kb

Influenza at the Human-Animal Interface Summary

Overall Public Health Risk

• New Infections: Reports of new human infections with A(H7N9), A(H9N2), and A(H1N1)v viruses.
• Risk Assessment: The overall public health risk from currently known influenza viruses at the human-animal interface remains unchanged. Further human infections from animal origin are expected, but sustained human-to-human transmission remains unlikely.
• Reporting: Human infections with new influenza subtypes are reportable under IHR (2005). Data informs ongoing risk assessments.

Risk Details

Avian Influenza A(H5) Viruses

• Current Situation: No new human H5 cases reported during this period. Cumulative H5N1 cases: 846 (449 deaths) from 16 countries; H5N6: 10 cases (6 deaths) in China since 2013. OIE reports H5 viruses active in birds across Africa, Europe, Asia.
• Risk Assessment:
  1. Further human cases expected due to ongoing circulation in birds.
  2. Low likelihood of sustained human-to-human transmission.
  3. Low risk of international spread causing community-level outbreaks.

Avian Influenza A(H7N9) Viruses

• Current Situation: China reported 28 new human cases (plus one from Hong Kong SAR); median age 58, majority male, most exposed to live poultry. Cumulative H7N9 cases worldwide: ~722 (at least 286 deaths). FAO reports virus persists in markets and farms in China.
• Risk Assessment:
  1. Further human cases expected due to virus circulation in environment/poultry.
  2. Low likelihood of sustained human-to-human transmission.
  3. Low risk of international spread leading to wider community transmission.

Avian Influenza A(H9N2) Viruses

• Current Situation: One human case reported from China (mild, ongoing investigation). Cumulative global cases: 28, usually mild, no evidence of sustained human-to-human spread. Virus endemic in poultry.
• Risk Assessment:
  1. Further cases expected from poultry contact.
  2. Low likelihood of sustained human-to-human transmission.
  3. Low risk of international spread causing wider transmission.

Swine Influenza A(H1N1)v Viruses

• Current Situation: Three human cases reported from China/Hunan and Yunnan provinces. Cumulative Chinese cases: 7. Virus circulation in pigs.
• Risk Assessment:
  1. Further cases expected, primarily from pig contact.
  2. Low likelihood of sustained human-to-human transmission.
  3. Low risk of international spread leading to local transmission.

Overall Risk Management Recommendations

1. No WHO advice for special traveller screening or trade restrictions.
2. WHO advises travellers to avoid exposure to animals/facilities where contact could occur. Handwashing is recommended.
3. Emphasis on continued global surveillance for influenza viruses.
4. IHR requires immediate notification for certain human influenza A cases (virus with pandemic potential). Lab characterization and sharing under the PIP framework is encouraged.