#17,925
On Wednesday we learned of Hong Kong's 9th confirmed case of H9 influenza (see Hong Kong CHP Investigating An H9 Infection), which is the first they've seen since 2020. Globally, a bit more than 100 cases have been confirmed (see FluTrackers list) although seroprevalence studies suggest that many cases go unreported.
Today HK's Centre for Health Protection (CHP) published the following update on their investigation, which confirms the subtype to be H9N2, reassures that no reassortment has occurred with seasonal flu, and indicates that no additional cases have been identified.
CHP reports investigation progress of case of influenza A (H9) infection
The Centre for Health Protection (CHP) of the Department of Health (DH) today (February 23) said that, regarding the human case of influenza A (H9) infection announced earlier, the subtype of the virus infected by the 22-month-old girl was confirmed as H9N2 by the Public Health Laboratory Services Branch of the CHP.
"According to the whole genome sequencing result, it is believed that the H9N2 virus isolated from sample of the patient are of avian origin. The relevant avian influenza virus showed no re-assortment with genes of human influenza origin. The CHP also found that the relevant H9N2 virus is sensitive to antiviral medicine Tamiflu." a spokesman for the CHP said.
The symptoms of the patient had subsided and is still undergoing isolation at Princess Margaret Hospital. She is now in stable condition. Also, the CHP earlier announced that one of her home contacts had presented with upper respiratory tract infection symptoms. Her nasopharyngeal aspirate sample tested negative against influenza A virus.
The CHP has already notified the health authority of the Mainland and the World Health Organization of the case. The CHP also uploaded the aforementioned genetic sequence result to the international genomic database GISAID. Epidemiological investigation of the case is ongoing.
Novel influenza A infection, including influenza A (H9), is a notifiable infectious disease in Hong Kong. Influenza A (H9N2) infection is a mild form of avian influenza. Nine cases of influenza A (H9N2) had been reported since 1999. The recent case was an imported case reported in 2020. No deaths have been recorded so far.
A stringent surveillance mechanism by the CHP with public and private hospitals, with practising doctors and at boundary control points is firmly in place. Suspected cases will be immediately referred to public hospitals for follow-up investigation.
"Travellers, especially those returning from avian influenza-affected areas and provinces 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 and provinces," the spokesman advised.
Members of the public should remain vigilant and take heed of the preventive advice against avian influenza below:The public may visit the CHP's avian influenza page (www.chp.gov.hk/en/view_content/24244.html) and website (www.chp.gov.hk/files/pdf/global_statistics_avian_influenza_e.pdf) for more information on avian influenza-affected areas and provinces.
- Do not visit live poultry markets. Avoid contact with poultry, birds and their droppings. If contact has been made, thoroughly wash hands with soap;
- 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); or 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;
- Wear masks when respiratory symptoms develop or when taking care of fever patients;
- Travellers if feeling unwell when outside Hong Kong, especially if having a fever or cough, should wear a surgical mask and inform the hotel staff or tour leader and seek medical advice at once; and
- Travellers returning from affected areas with avian influenza outbreaks should consult doctors promptly if they have flu-like symptoms, and inform the doctor of the travel history and wear a surgical mask to help prevent spread of the disease.
Ends/Friday, February 23, 2024
Issued at HKT 20:30
While H9N2 infection is generally mild or moderate in humans, this LPAI subtype easily reassorts with other flu viruses, making any infection a concern.
During flu season, the possibility exists that someone could be co-infected with seasonal flu and H9N2, making it possible that a hybrid (reassortment) might emerge (see The `Other Mixing Vessel' For Pandemic Influenza).
. While the odds of that happening may be long, they are not zero. Which is why HK's CHP is taking this investigation seriously.
