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A Highly Pathogenic #Avian #H7N9 #Influenza Virus Isolated from A #Human Is Lethal in Some #Ferrets Infected via #Respiratory #Droplets (Cell Host Microbe, abstract)

Title : A Highly Pathogenic #Avian #H7N9 #Influenza Virus Isolated from A #Human Is Lethal in Some #Ferrets Infected via #Respiratory #Drop...

22 Feb 2017

#Avian #Influenza A (#H7N9) Virus–February 22 2017 #Update (@CDCgov, Edited)


Title: #Avian #Influenza A (#H7N9) Virus–February 22 2017 #Update.

Subject: Avian Influenza, H7N9 subtype, human cases in various provinces of China.

Source: US Centers for Disease Control and Prevention (CDC), full page: (LINK).

Code: [     ]


Avian Influenza A (H7N9) Virus


Language: [ English | Español ]


H7N9 Outbreak Characterization

  • H7N9 infections in people and poultry in China
  • Sporadic infections in people; most with poultry exposure
  • Rare limited person-to-person spread
  • No sustained or community transmission


What's New & Updated

  • H7N9: What should I do?
    • CDC does not have any new or special recommendations for the U.S. public at this time regarding H7N9. CDC will keep you updated. Stay informed.
    • Since H7N9 is not spreading easily from person to person at this time, CDC does not recommend that people delay or cancel trips to China.
      • The World Health Organization also is watching this situation closely and does not recommend any travel restrictions.
    • CDC advises travelers to China to take some common sense precautions, like not touching birds and washing hands often.
      • Poultry and poultry products should be fully cooked.
      • CDC will update its advice for travelers if the situation in China changes.
      • This guidance is available at Avian Flu (H7N9) in China.





  • Most human infections with H7N9 virus have occurred after exposure to poultry; H7N9 viruses continue to circulate in poultry in China.
  • Most reported patients with H7N9 virus infection have had severe respiratory illness (e.g., pneumonia); about 40% of patients have died.
  • Rare instances of limited person-to-person spread of this virus have been identified in China, but there is no evidence of sustained person-to-person spread of H7N9 virus.
  • Some cases of H7N9 have been reported outside of mainland China but most of these infections have occurred among people who had traveled to mainland China before becoming ill.
  • H7N9 viruses have not been detected in people or birds in the United States.


CDC Risk Assessment

  • While the current risk to the public’s health posed by H7N9 virus is low, the pandemic potential of this virus is concerning.
    • Influenza viruses constantly change and it’s possible that this virus could gain the ability to spread easily and sustainably among people, triggering a global outbreak of disease (pandemic).
    • In fact, of the influenza A viruses that are of special concern to public health, H7N9 virus is rated by the Influenza Risk Assessment Tool (IRAT), as having the greatest potential to cause a pandemic, as well as potentially posing the greatest risk to severely impact public health.
  • It’s likely that sporadic human infections with H7N9 virus associated with poultry exposure will continue to occur in China.
    • It's also possible that H7N9 virus may spread to poultry in neighboring countries and that human cases associated with poultry exposure may be detected in neighboring countries.
    • It’s also possible that H7N9 cases may continue to be detected among travelers returning from H7N9 virus-affected countries, even possibly in the United States.
    • However, as long as there is no evidence of ongoing, sustained person-to-person spread of H7N9 virus, the public health risk assessment would not change substantially.


CDC Response

  • The U.S. Government supports international surveillance for H7N9 virus and other influenza A viruses with pandemic potential.
    • CDC is following the H7N9 situation closely and coordinating with domestic and international partners.
    • CDC takes routine preparedness actions whenever a new virus with pandemic potential is identified, including developing candidate vaccine viruses to use for vaccine production in case vaccine is needed.
    • CDC has already developed 3 H7N9 candidate vaccine viruses (CVVs).
    • These remained antigenically like H7N9 viruses that were circulating during the 4th epidemic.
    • Genetic and antigenic analysis of viruses from the 5th epidemic is ongoing at CDC.
    • This includes looking at viruses from the 5th epidemic to consider whether an updated candidate vaccine virus might be needed.
    • CDC also will look at 5th epidemic viruses to see whether these remain susceptible to the antiviral drugs classified as neuraminidase inhibitors.
    • CDC has issued guidance to clinicians and public health authorities in the United States, as well as provided information for people traveling to China.
    • CDC will provide updated information as it becomes available.


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Keywords: US CDC; USA; Updates; Avian Influenza; Human; China; H7N9.