Human infection with avian influenza A(H7N9) virus – China
On 20 December 2016, the Department of Health (DOH), Hong Kong Special Administrative Region (SAR) notified WHO of a case of laboratory-confirmed human infection with avian influenza A(H7N9) virus.
Details of the case
The case is a 75-year-old man who travelled to Dongguan, Guangdong province from 28 November to 9 December 2016. He developed chest discomfort on 8 December and he visited a hospital there. He returned to Hong Kong SAR on 9 December and was directly admitted to hospital from point of entry by ambulance for cough with sputum, shortness of breath, runny nose and chest discomfort.
His nasopharyngeal swab taken on 9 December tested positive for enterovirus/ rhinovirus and negative for influenza virus. His nasopharyngeal aspirate (NPA) taken on 19 December was positive for avian influenza A(H7N9) virus RNA. He was reported to be in severe condition at the time of report. His condition further deteriorated to critical on 21 December. He had visited a wet market in Dongguan and bought a dressed chicken. DOH's investigation is ongoing, and DOH is communicating with the Guangdong health authority.
To date, a total of 808 laboratory-confirmed human infections with avian influenza A(H7N9) virus have been reported through IHR notification since early 2013.
Public health response
The Centre for Health Protection of the Department of Health has taken the following measures:
- Urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
- Issued an alert to doctors, hospitals, schools and institutions of the latest situation.
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 it 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.