On 19 June 2017, the National Health and Family Planning Commission of China (NHFPC) notified WHO of five additional laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus in China. On 24 June 2017, the NHFPC notified WHO of 10 additional laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus in China. On 30 June 2017, the NHFPC notified WHO of six additional laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus in China.
On 19 June 2017, the NHFPC reported five laboratory-confirmed human cases of infection with avian influenza A(H7N9) virus in China. Onset dates ranged from 25 April to 6 June 2017. Of these five cases, one was female. The median age was 55 years (range 41 to 68 years). The case patients were reported from Beijing (1), Guangxi (1), Guizhou (1), Hunan (1), and Zhejiang (1). At the time of notification, there was one death. Four cases were diagnosed as having severe pneumonia. Three cases were reported to have had exposure to poultry or live poultry market, and two had no known poultry exposure. No case clustering was reported.
On 24 June 2017, the NHFPC reported 10 laboratory-confirmed human cases of infection with avian influenza A(H7N9) virus in China. Onset dates ranged from 5 to 19 June 2017. All cases were male. The median age was 53.5 years (range 31 to 79 years). The cases were reported from Anhui (1), Beijing (2), Guizhou (1), Hebei (1), Inner Mongolia (1), Jiangsu (1), Sichuan (2), and Tianjin (1). This is the first case reported in Inner Mongolia since the virus emerged in 2013 although two cases were recently reported from Shaanxi province but who had likely exposure in Inner Mongolia. At the time of notification, there were two deaths. Eight cases were diagnosed as having either pneumonia (4) or severe pneumonia (4). Nine cases were reported to have had exposure to poultry or live poultry market, and one had no known poultry exposure.
One cluster with two cases was reported and both cases are from Panzhihua City, Sichuan Province, and had exposure to the same live poultry market. The cluster includes:
On 30 June 2017, the NHFPC reported six laboratory-confirmed human cases of infection with avian influenza A(H7N9) virus in China. Onset dates ranged from 11 to 23 June 2017. Three cases were male. The median age was 37.5 years (range 4 to 72 years). The cases were reported from Guizhou (1), Shanxi (1), and Yunnan (4) provinces. At the time of notification no associated deaths were reported. Four cases were diagnosed as having either pneumonia (1) or severe pneumonia (3). Two mild cases, identified through ILI surveillance, were reported: one in a child with exposure to market poultry and one in an adult. Five cases were reported to have had exposure to poultry or live poultry market, and one had no known poultry exposure. These are the first cases reported with exposure to the virus in Yunnan province. Previous cases reported from Yunnan province had likely exposure in a neighbouring province.
One cluster with two cases was reported, which include:
To date, a total of 1554 laboratory-confirmed human infections with avian influenza A(H7N9) virus have been reported through IHR notification since early 2013.
The Chinese government at national and local level is taking preventive measures which include:
The number of human infections with avian influenza A(H7N9) virus and the geographical distribution in the fifth epidemic wave (i.e. onset since 1 October 2016) is greater than earlier waves. This suggests that the virus is spreading, and emphasizes that further intensive surveillance and control measures in both human and animal health sector are crucial.
According to the epidemiological curve, the number of reported cases on a weekly basis seems to have peaked in early February and is slowly decreasing. The peak in cases this year corresponds to the timing of the peak in cases in previous years.
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, and live poultry vending continues, further human cases can be expected. Additional sporadic human cases of avian influenza A(H7N9) in other provinces in China that have not yet reported human cases are also expected. Similarly, sporadic human cases of avian influenza A(H7N9) detected in countries bordering China would not be unexpected. Although small clusters of cases of human infection with avian influenza A(H7N9) virus have been reported including those involving patients in the same ward, current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans. Therefore the likelihood of further community level spread is considered low.
Close analysis of the epidemiological situation and further characterization of the most recent viruses are critical to assess associated risk and to adjust risk management measures in a timely manner.
WHO advises that travellers to countries with known outbreaks of avian influenza should avoid, if possible, poultry farms, contact with animals in live poultry 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.