Human avian influenza A (H7N9) virus infection – China

On 18, 25 August and 4 September 2017, China notified the National Health and Family Planning Commission (NHFPC) to WHO of four additional laboratory confirmed cases of human avian influenza A (H7N9) virus infection in China.

Details of patients

On 18 August 2017, the NHFPC reported one laboratory-confirmed human case of avian influenza A (H7N9) virus infection in China. The case patient was a 47-year-old man from Hunan province who developed symptoms on August 9, 2017, and was admitted to hospital on August 12, 2017. He died on August 13, 2017. He was reported to have been exposed to live poultry markets.

On 25 August 2017, the NHFPC reported two cases of human avian influenza A (H7N9) infection in China. Two patients were from Xinjiang Uyghur Autonomous Region. The first patient of the case was a 73-year-old man with symptom on 7 August 2017 and admitted to hospital with severe pneumonia on 14 August 2017. He was exposed at live poultry markets. The second case patient was a man aged 74 with onset of symptoms also on August 7, 2017 and admitted to hospital with severe pneumonia on August 12, 2017. He had no exposure to live poultry. Both cases were in serious condition at the time of reporting. Although the two cases are reported from the same region, they live in different communities and there is no known epidemiological link between the cases.

On September 4, 2017, the NHFPC reported one laboratory-confirmed case of avian influenza A (H7N9) virus infection in China. The case patient was a 58-year-old man from Jiangsu Province. He developed symptoms on August 9, 2017, was admitted to hospital on August 14, 2017, and passed away August 25, 2017. He is reported to have been exposed to live poultry markets.

To date, a total of 1562 laboratory-confirmed human avian influenza A (H7N9) virus infections have been reported through IHR notification since the beginning of 2013.

Public health response

The GOC estimates that although rare cases of avian influenza A (H7N9) have been reported in recent weeks, it is still likely that sporadic cases will continue to occur in China, taking into account previous epidemiological situations and recent patterns.

Therefore, government at national and local level continues to take preventive measures which include:

• Continuing guidance to provinces to strengthen assessment and prevention and control measures.
• Leading provinces to use the current low frequency period to review prevention and control efforts taken to facilitate the implementation of long-term measures.
• Continuing to communicate risk and issue publicity notices to provide guidance on self-care.

The government has warned the provinces that the prevention and control of infections cannot be easily treated and that they should be on standby to ensure timely and effective case detection and management.

WHO risk assessment

As we have seen in previous years, the number of cases reported weekly decreased during the summer months. However, the number of human avian influenza A (H7N9) infections and the geographical spread in the fifth epidemiological wave (i.e., the attacks since October 1, 2016) are still higher than the earlier waves. This suggests that the virus has spread and emphasizes that further intensive surveillance and surveillance measures in the human and animal health sector remain crucial.

Most human cases are exposed to avian influenza A (H7N9) virus through contact with infected poultry or contaminated environments, including the live poultry market. As the virus continues to be found in animals and the environment, and poultry sales continue to occur, further cases in humans can be expected. Additional sporadic human cases of avian influenza A (H7N9) in provinces in China that have not yet reported cases of human origin are also expected. Similarly, sporadic cases of human influenza A (H7N9) detected in countries bordering China would not be unexpected. Although small clusters of cases of avian influenza A (H7N9) infection have been reported, including those involving patients in the same ward, current epidemiological and virological evidence indicates that this virus has not acquired the ability to transmit sustainably among humans. Therefore, the likelihood of further spread at the community level is considered low.

Careful analysis of the epidemiological situation and further characterization of the latest viruses are crucial for assessing the associated risk and adapting risk management measures in a timely manner.

Tip of WHO

WHO advises that travelers to countries with known avian influenza outbreaks, if possible, avoid poultry farms, contact animals at live poultry markets, enter areas where poultry may be slaughtered or contact any surface that appears to be poultry. contaminated by poultry. or other animals. Travelers should also wash their hands frequently with soap and water and follow good food safety and hygiene practices.

WHO does not advise a special entry point review nor does it currently recommend any travel or trade restrictions regarding this event. As always, the diagnosis of avian influenza infection should be considered in people who develop severe acute respiratory symptoms while traveling to or shortly after returning from an avian influenza area.

WHO encourages countries to continue to strengthen their surveillance of influenza, including surveillance for severe acute respiratory infections (SARI) and influenza-like illness (OR), and to carefully review any unusual patterns; ensures reporting of human infections in accordance with IHR 2005; and continue with national health readiness actions.