Human infection with avian influenza A(H7N9)- bird flu

Human infection with bird flu virus A (H7N9) – China

avian influenza
avian influenza

avian influenza A(H7N9)

On March 31, 2017, China’s National Family Planning and Health Commission (NHFPC) notified the WHO of 17 new laboratory-confirmed cases of human A / H1N9 avian influenza A(H7N9)/ virus infection in mainland China.

Details of the cases


The dates of appearance ran from March 6 to March 24, 2017. Of these 17 cases, three were women. The median age is 53 years (the age range between cases is 35 to 81 years). Cases were reported from Fujian (2), Guangxi (3), Guizhou (2), Hunan (6), Jiangsu (3) and Zhejiang (1).

At the time of notification, there were three deaths, and 14 cases were diagnosed as pneumonia (4) or severe pneumonia (10). It was reported that sixteen cases had been exposed to poultry or live poultry market. One case had no history of exposure to poultry. No clusters were reported.

To date, 1364 laboratory-confirmed human infections with avian influenza A (H7N9) virus have been reported through IHR reporting since early 2013.


Public health response

Taking into account the increase in the number of human cases since December 2016, the Chinese government at national and local levels is taking additional measures including:

  • Continue to strengthen control measures focused on the hygienic management of live poultry markets and trans-regional transport.
  • Require all provinces to remain vigilant and to fully implement control and prevention measures.
    Increase attention and guidance to certain central and western provinces that are reporting more cases to strengthen control and prevention.
  • Performing public communication of risk and advertising information to provide the public with guidelines on self-protection.
  • Strengthening etiology screening and surveillance research to define the extent of virus contamination and mutations, in order to provide more guidance for prevention and control.

WHO risk assessment

The number of human infections with avian influenza A (H7N9) in the fifth epidemic wave (ie, since 1 October 2016) is greater than the number of human cases reported in previous waves.

Human infections with bird flu virus A (H7N9) remain unusual. Careful observation of the epidemiological situation and the subsequent characterization of the most recent human viruses are critical for assessing the associated risk and for adjusting risk management measures in a timely manner.

Most human cases are exposed to avian influenza A (H7N9) virus by contact with infected poultry or contaminated environments, including live poultry markets. As the virus continues to be detected in animals and environments, and the continued sale of poultry continues, more human cases can be expected. Although small groups of cases of human infection with A (H7N9) avian influenza virus, including those involving patients in the same neighborhood, have been reported, current epidemiological and virological evidence suggests that this virus has not Sustained transmission between humans. Therefore, the likelihood of further spread at Community level is considered low.


WHO advice

WHO recommends travelers to countries with known outbreaks of bird flu to avoid, if possible, poultry farms, contact with animals in live poultry markets, poultry entry areas Or contact with contaminated surfaces with feces of poultry or other animals. Travelers should also wash hands frequently with soap and water, and follow good food hygiene and food safety practices.

WHO does not recommend special screening at points of entry regarding this event, nor does it currently recommend any travel or trade restrictions. As always, a diagnosis of avian influenza virus infection should be considered in individuals who develop severe acute respiratory symptoms while traveling on or shortly after returning from an area where bird flu is a concern.

WHO encourages countries to further strengthen influenza surveillance, including surveillance for severe acute respiratory infections (SARI) and influenza-like illnesses (ILI), and carefully review any unusual patterns, ensure notification of infections In the 2005 IHR and continue national preparedness for health behavior.