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While there is still remarkably little mention of the case in Chinese media, in the past hour Macao has issued a statement on the H3N8 case reported today from neighboring Zhongshan City.
1 case of human infection with H3N8 bird flu confirmed in Guangdong Province
source:Health Service (SS)
release date:March 27, 2023 at 19:27
The Health Bureau stated that according to the announcement of the health department in the Mainland, a case of human infection with the H3N8 avian influenza virus was confirmed in Guangdong Province. Residents are urged to avoid contact with poultry and birds, and pay attention to personal and food hygiene.
According to the notification information, the patient is a 56-year-old female who lives in Zhongshan City, Guangdong Province. She has a basic medical history, a history of exposure to live poultry before the onset of the disease, and a history of wild bird activities around her home.
The H3N8 avian influenza virus is an avian-origin virus, which cannot be directly transmitted between humans, and the risk of large-scale transmission is low. The H3N8 virus has been detected globally in horses, dogs, poultry and seals.
The Health Bureau will continue to maintain close contact with the health departments of the country and neighboring regions, and the World Health Organization, and closely monitor the epidemic situation in various places and Macao. To prevent human infection with avian influenza, the Health Bureau appeals to the public to pay attention to the following:
- Avoid contact with birds or their secretions and excreta; if in contact, wash your hands immediately;
- Do not buy or carry unquarantined poultry;
- Do not eat poultry meat, offal, blood products and eggs that have not been thoroughly cooked;
- Pay attention to personal hygiene and wash hands frequently;
- If symptoms such as fever, cough, and difficulty breathing occur, you should wear a mask, seek medical treatment as soon as possible, and describe your travel history and animal contact history to the doctor in detail.
For information on avian influenza, please visit the website of the Health Bureau (www.ssm.gov.mo) or call the infectious disease hotline of the Health Bureau at 28700800 during office hours.
So far, Hong Kong's CHP has yet to make an announcement. Last May they were conspicuously late in announcing the second case (see Hong Kong CHP Finally Notified Of 2nd H3N8 Case On the Mainland), so it is not all that surprising.
While any spillover of a novel flu virus to humans is noteworthy, those belonging to the H1, H2, and H3 HA subtypes are of particular concern because all known human influenza pandemics going back 130 years have come from one of these 3 subtypes (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).
Earlier this month we took a look at a study by Chinese researchers on the evolution and spread of H3N8 (and other) avian flu viruses in Eastern China (see Emerging Microbes & Inf.: Prevalence, Evolution, Replication and Transmission of H3N8 Avian Influenza Viruses).
The authors wrote:
Genetic and phylogenetic analyses showed that the H3N8 viruses circulating in migratory birds and ducks have evolved into different branches and have undergone complicated reassortment with viruses in waterfowl. The 21 viruses belonged to 12 genotypes, and some strains induced body weight loss and pneumonia in mice. All the tested H3N8 viruses preferentially bind to avian-type receptors, although they have acquired the ability to bind human-type receptors.
Infection studies in ducks, chickens and pigeons demonstrated that the currently circulating H3N8 viruses in migratory birds have a high possibility of infecting domestic waterfowl and a low possibility of infecting chickens and pigeons.
Our findings imply that circulating H3N8 viruses in migratory birds continue to evolve and pose a high infection risk in domestic ducks. These results further emphasize the importance of avian influenza surveillance at the wild bird and poultry interface.
Although this is only the 3rd known human infection with H3N8, it requires a good deal of luck for a case to be picked up by surveillance, and then get reported.
First, the patient must be sick enough to be hospitalized, and then lucky enough to receive the proper tests. And often, that simply doesn't happen.
So while rare, spillover of H3N8 (and other novel flu viruses) are probably more common than we know.
Stay tuned.
