Mainland China's summer surge in human H5N6 infections continues today, with a new case reported in Hunan Province. This is the 19th case reported by China since last December, meaning that over 42% of all known cases (since the virus emerged in 2014) have been reported over the past 10 months.
Prior to the past year, we'd never seen more than 9 cases reported in any calendar year (2016).
While we've not seen any obvious clustering of cases (other than a husband & wife in Hunan province who likely shared an exposure), this abrupt uptick in H5N6 cases - particularly occurring in late summer - is concerning, as this is normally the slowest time of the year for avian flu transmission.
H5N6 reports declined dramatically between the summer of 2017 and the summer of 2020, following the nationwide release of a new H5+H7 poultry vaccine in China (see OFID: Avian H5, H7 & H9 Contamination Before & After China's Massive Poultry Vaccination Campaign).
First today's Hong Kong report, then I'll return with a brief postscript.
CHP closely monitors human case of avian influenza A(H5N6) in Mainland
The Centre for Health Protection (CHP) of the Department of Health is today (September 17) closely monitoring a human case of avian influenza A(H5N6) in the Mainland, and again urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
The case involves a 40-year-old woman living in Yongzhou in Hunan Province, who had prior exposure to a live poultry market before the onset of symptoms. She developed symptoms on September 8 and was admitted for treatment on the following day. The patient is in serious condition.
From 2014 to date, 43 human cases of avian influenza A(H5N6) have been reported by Mainland health authorities.
"All novel influenza A infections, including H5N6, are notifiable infectious diseases in Hong Kong," a spokesman for the CHP said.
Travellers to the Mainland or other affected areas must avoid visiting wet markets, live poultry markets or farms. They should be alert to the presence of backyard poultry when visiting relatives and friends. They should also avoid purchasing live or freshly slaughtered poultry, and avoid touching poultry/birds or their droppings. They should strictly observe personal and hand hygiene when visiting any place with live poultry.
Travellers returning from affected areas should consult a doctor promptly if symptoms develop, and inform the doctor of their travel history for prompt diagnosis and treatment of potential diseases. It is essential to tell the doctor if they have seen any live poultry during travel, which may imply possible exposure to contaminated environments. This will enable the doctor to assess the possibility of avian influenza and arrange necessary investigations and appropriate treatment in a timely manner.
While local surveillance, prevention and control measures are in place, the CHP will remain vigilant and work closely with the World Health Organization and relevant health authorities to monitor the latest developments.
The public should maintain strict personal, hand, food and environmental hygiene and take heed of the advice below when handling poultry:
Avoid touching poultry, birds, animals or their droppings;
The public may visit the CHP's pages for more information: the avian influenza page, the weekly Avian Influenza Report, global statistics and affected areas of avian influenza, the Facebook Page and the YouTube Channel.
- When buying live chickens, do not touch them and their droppings. Do not blow at their bottoms. Wash eggs with detergent if soiled with faecal matter and cook and consume the eggs immediately. Always wash hands thoroughly with soap and water after handling chickens and eggs;
- Eggs should be cooked well until the white and yolk become firm. Do not eat raw eggs or dip cooked food into any sauce with raw eggs. Poultry should be cooked thoroughly. If there is pinkish juice running from the cooked poultry or the middle part of its bone is still red, the poultry should be cooked again until fully done;
- Wash hands frequently, especially before touching the mouth, nose or eyes, before handling food or eating, and after going to the toilet or touching public installations or equipment, such as escalator handrails, elevator control panels or door knobs, or when hands are dirtied by respiratory secretions after coughing or sneezing; and
- Wear a mask if fever or respiratory symptoms develop, when going to a hospital or clinic, or while taking care of patients with fever or respiratory symptoms.
Ends/Friday, September 17, 2021
Issued at HKT 17:42
While human H5N6 infections still appear to be rare, iis likely that many - probably most - have gone unrecognized. Many people get infected with, and even die from, severe influenza in China (and other parts of Asia) and are never hospitalized or tested.
In the early days of 2013's H7N9 outbreak in China, we saw credible estimates (see Lancet: Clinical Severity Of Human H7N9 Infection) suggesting that the true number of cases might have run between 10 and 100 times higher than reported.
It doesn’t matter whether we are talking about seasonal influenza, West Nile Virus, Salmonella, or avian flu, we are almost always dealing with a subset of the actual number of cases.
Unless, and until, HPAI H5N6 becomes easily transmissible among humans - it will remain a localized problem - and mostly a concern for those raising poultry. But each human infection provides another opportunity for the virus to better adapt to human physiology, which makes this recent uptick worthy of our attention.
It is also worth noting that while most of those who have been infected had recent, close contact with poultry, we've not been hearing of any poultry outbreaks of HPAI H5N6 from China's MOA.
While it is possible that China is simply not reporting poultry outbreaks, another possibility is the H5N6 virus is spreading asymptomatically in vaccinated poultry (see PLoS Bio: Imperfect Poultry Vaccines, Unintended Results), allowing it to spread without notice.
Either way, with fall approaching, we'll be monitoring H5N6 (and other) avian influenza viruses with considerable interest.