While our attention has been on HPAI H5N8 in Europe these past few days, this is also the time of year when we expect the return of of other avian flu subtypes, particularly H7N9 in China.
Since 2013 we've seen a winter epidemic of human H7N9 infections across China, with cases generally picking up in November and peaking between January and March (see chart above).
Most human infections appear to be acquired via close contact with asymptomatically infected poultry at live bird markets, although China's surveillance and reporting is likely only to pick up the `sickest of the sick', and many mild cases are believed to go undetected.
Over the years we've also seen some subtle changes in the virus's behavior, including an increase in the number of apparent clusters, and the WHO's risk assessment over the summer read:
Although small clusters of human cases with influenza A(H7N9) viruses have been reported previously 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, community level spread of this virus is considered unlikely for the time being..
We looked at other changes last May in EID Journal: Human Infection With H7N9 During 3 Epidemic Waves - China, which found that patients hospitalized in the 2nd and 3rd wave with severe H7N9 tended to be younger, and from more rural areas, than those from the 1st wave.
They also found that the risk of death among hospitalized patients was greater in the second and third waves, although that varied between provinces.
The H7N9 virus continues to evolve and spread in China, and it remains high on our watch list, along with venerable H5N1 and the emerging H5N6 virus. The only constant with novel flu in China is that it is always changing.
After several months with little H7N9 activity to report, today Hong Kong's Centre For Health Protection announced two new (or recent) human cases on the Mainland.
The Centre for Health Protection (CHP) of the Department of Health (DH) today (November 11) received notification of two additional human cases of avian influenza A(H7N9) from the National Health and Family Planning Commission (NHFPC), and again urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
The two patients are:
- A female farmer aged 77 from Huzhou, Zhejiang, in serious condition. She bought poultry from a live poultry market before onset; and
- A man aged 89 from Suzhou, Jiangsu, in serious condition.
"As winter approaches, based on the seasonal pattern of avian influenza viruses, their activity in the Mainland is expected to increase. The public should avoid contact with poultry, birds and their droppings and should not visit live poultry markets and farms to prevent avian influenza," a spokesman for the CHP said.
From 2013 to date, 777 human cases of avian influenza A(H7N9) have been reported by the Mainland health authorities.
"We will remain vigilant and work closely with the World Health Organization and relevant health authorities to monitor the latest developments," the spokesman said.
The CHP's Port Health Office conducts health surveillance measures at all boundary control points. Thermal imaging systems are in place for body temperature checks on inbound travellers. Suspected cases will be immediately referred to public hospitals for follow-up.
The display of posters and broadcasting of health messages in departure and arrival halls as health education for travellers is under way. The travel industry and other stakeholders are regularly updated on the latest information.
Travellers, especially those returning from avian influenza-affected areas with fever or respiratory symptoms, should immediately wear masks, seek medical attention and reveal their travel history to doctors. Healthcare professionals should pay special attention to patients who might have had contact with poultry, birds or their droppings in affected areas.
The public should remain vigilant and take heed of the advice against avian influenza below:
- Do not visit live poultry markets and farms. Avoid contact with poultry, birds and their droppings;
- If contact has been made, thoroughly wash hands with soap;
- Avoid entering areas where poultry may be slaughtered and contact with surfaces which might be contaminated by droppings of poultry or other animals;
- Poultry and eggs should be thoroughly cooked before eating;
- Wash hands frequently with soap, especially before touching the mouth, nose or eyes, handling food or eating; after going to the toilet or touching public installations or equipment (including escalator handrails, elevator control panels and door knobs); and when hands are dirtied by respiratory secretions after coughing or sneezing;
- Cover the nose and mouth while sneezing or coughing, hold the spit with a tissue and put it into a covered dustbin;
- Avoid crowded places and contact with fever patients; and
- Wear masks when respiratory symptoms develop or when taking care of fever patients.
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.Ends/Friday, November 11, 2016Issued at HKT 17:43