Human infection with avian influenza A(H7N9) virus – China
On 12 December 2016, the National Health and Family Planning Commission (NHFPC) of China notified WHO of six (6) additional cases of laboratory-confirmed human infection with avian influenza A(H7N9) virus.
Onset date of symptoms ranged from 6 to 20 November 2016. Cases ranged in age from 32 to 80 years with a median age of 61 years, and all cases are male. All cases were hospitalized and reported to be in a severe condition.
Five (5) cases reported exposure to live poultry or live poultry markets. One (1) case has no clear history of exposure to live poultry. Cases were reported from three (3) provinces; Jiangsu (4), Fujian (1) and Guangdong (1). No clusters of cases were reported.
To date, a total of 806 laboratory-confirmed human cases with avian influenza A (H7N9) virus have been reported through IHR notification since early 2013.
Public health response
The Chinese Government has taken the following surveillance and control measures:
- Strengthened surveillance and assessment analysis.
- Further enhanced medical care of the cases.
- Conducted public risk communication.
WHO risk assessment
Most human cases are exposed to avian influenza A(H7N9) virus through contact with infected poultry or contaminated environments, including live poultry markets. Since the virus continues to be detected in animals and environments, further human cases can be expected. Although small clusters of human cases with avian influenza A(H7N9) virus have been reported including those involving healthcare workers, current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans. Therefore further community level spread is considered unlikely.
Human infections with the avian influenza A(H7N9) virus are unusual and need to be monitored closely in order to identify changes in the virus and/or its transmission behaviour to humans as the virus may have a serious public health impact.
WHO advises that travellers to countries with known outbreaks of avian influenza should avoid, if possible, poultry farms, contact with animals in live bird markets, entering areas where poultry may be slaughtered, or contact with any surfaces that appear to be contaminated with faeces from poultry or other animals. Travellers should also wash their hands often with soap and water, and follow good food safety and good food hygiene practices.
WHO does not advise special screening at points of entry with regard to this event, nor does it currently recommend any travel or trade restrictions. As always, a diagnosis of infection with an avian influenza virus should be considered in individuals who develop severe acute respiratory symptoms while travelling in or soon after returning from an area where avian influenza is a concern.
WHO encourages countries to continue strengthening influenza surveillance, including surveillance for severe acute respiratory infections (SARI) and influenza-like illness (ILI) and to carefully review any unusual patterns, ensure reporting of human infections under the IHR (2005), and continue national health preparedness actions.