Michael Coston
Editor, Senior Moderator
Hong Kong CHP: Cryptic Announcement of 1 New H10N3, and 2 H9N2 Cases on the Mainland
#19,049
As we've discussed previously, in HK CHP: Another Cryptic Announcement of H9N2 Cases From the Chinese Mainland, reports out of China are often belated, and lack many critical details.
The barebones report above is a prime example.
It is worth noting that the WHO's WPRO published an update last Friday, which reported no new human novel flu infections in the region, including the following summary on H10N3:
From 30 January to 5 February 2026, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 21 April 2025. To date, six cases of human infection with avian influenza A(H10N3) have been reported globally.
Hopefully we'll learn more about this 7th case, including its severity and likely source of infection, from the next WHO Influenza at the human-animal interface report.
While most confirmed H10N3 cases have produced severe illness, we have no idea how many mild, or subclinical, infections may have gone unreported. We continue to see cautionary reports, however, from Chinese researchers on the human health threat from this emerging subtype.
Last October, in China CDC Weekly: Epidemiological and Genetic Characterization of Three H9N2 Viruses Causing Human Infections, we looked at a local CDC investigation into 3 pediatric cases which were reported last April from Changsha City, Hunan Province, China.
Their report found a number of indicators of increased mammalian adaptation within the virus, including an enhanced ability to infect upper respiratory (α2,6-sialic acid) tract receptors, and a number of HA protein mutations, including; H191N, A198V, Q226L, and Q234L.
Both viruses are reminders that while H5N1 may garner the bulk of avian flu headlines, there are a number of legitimate contenders for becoming the next pandemic threat.
https://afludiary.blogspot.com/2026/02/hong-kong-chp-cryptic-announcement-of-1.html
#19,049
As we've discussed previously, in HK CHP: Another Cryptic Announcement of H9N2 Cases From the Chinese Mainland, reports out of China are often belated, and lack many critical details.
The barebones report above is a prime example.
It is worth noting that the WHO's WPRO published an update last Friday, which reported no new human novel flu infections in the region, including the following summary on H10N3:
From 30 January to 5 February 2026, no new case of human infection with avian influenza A(H10N3) virus was reported to WHO in the Western Pacific Region. The last case was reported from China with an onset date of 21 April 2025. To date, six cases of human infection with avian influenza A(H10N3) have been reported globally.
Hopefully we'll learn more about this 7th case, including its severity and likely source of infection, from the next WHO Influenza at the human-animal interface report.
While most confirmed H10N3 cases have produced severe illness, we have no idea how many mild, or subclinical, infections may have gone unreported. We continue to see cautionary reports, however, from Chinese researchers on the human health threat from this emerging subtype.
- In July 2024, in Frontiers: Phylogenetic and Mutational Analysis of H10N3 Avian Influenza A virus in China: Potential Threats to Human Health, we looked at a report that described 4 mutations of concern in the 2023 case (HA Q226L, PB2 D701N, PA S409N, and M2 S31N), along with the patient's treatment and course of illness.
- Also in 2024 in Vet. Microbiology: The novel H10N3 Avian Influenza Virus Acquired Airborne Transmission Among Chickens: An Increasing Threat to Public Healthreported the virus has become better adapted to poultry, is highly pathogenic in mice, can be transmitted via respiratory droplets between guinea pigs, and can also be transmitted via the airborne route by chickens.
- And last June in Vet. Research: E627V Mutation in PB2 Protein Promotes the Mammalian Adaptation of Novel H10N3 Avian Influenza Virus reported that that PB2-626V is becoming increasingly common in AIV poultry isolates - including H10N3 - and that it significantly enhances mammalian adaptation while maintaining fitness in avian hosts.
Last October, in China CDC Weekly: Epidemiological and Genetic Characterization of Three H9N2 Viruses Causing Human Infections, we looked at a local CDC investigation into 3 pediatric cases which were reported last April from Changsha City, Hunan Province, China.
Their report found a number of indicators of increased mammalian adaptation within the virus, including an enhanced ability to infect upper respiratory (α2,6-sialic acid) tract receptors, and a number of HA protein mutations, including; H191N, A198V, Q226L, and Q234L.
Both viruses are reminders that while H5N1 may garner the bulk of avian flu headlines, there are a number of legitimate contenders for becoming the next pandemic threat.
https://afludiary.blogspot.com/2026/02/hong-kong-chp-cryptic-announcement-of-1.html