#18,587
While our biggest avian flu concern remains HPAI H5N1, over the years we've seen closely related H5N2, H5N3, H5N4, H5N5, H5N6, H5N8, and H5N9 viruses - the product of H5N1 reassorting with other LPAI viruses - infecting both birds and mammals around the globe.
While most have struggled to compete with H5N1, between 2014-2020, HPAI H5N8 became the dominant subtype globally, and HPAI H5N6 viruses have shown persistence in China and East Asia for more than a decade.
Since regaining its mantle in 2021, H5N1 has had little competition. But over the past few years we've seen reports of an H5N5 variant - first in Europe and Asia, then in Canada - which has not only managed to survive, it appears to be thriving.
They wrote:Not quite 3 weeks ago, the Icelandic Food and Veterinary Authority (MAST) reported an H5N5 Infection In Domestic Cat. Several days later, MAST reported another cat infected (see translation below).
Thus, while A(H5N5) viruses are comparably uncommon, their high virulence and mortality potential demand global surveillance and further studies to untangle the molecular markers influencing virulence, transmission, adaptability, and host susceptibility.
News - 10.01.2025
As stated in the Food Agency's report earlier this week, bird flu H5N5 was diagnosed for the first time in cats killed before Christmas. Today, the UI Experimental Plant analyzed pathology that Keldum had bird flu H5N5 in other cats. That cat was from a home in Seltjarnarnes. He had been ill with similar symptoms to the previous cat; fever, weakness and nervousness (seizures and stiffness), before being killed. He is most likely to have been infected with bird seed. Other cats are in the home and they are healthy. There is no connection between the cats that have been diagnosed with bird flu. There is no indication that the bird flu is infected between cats.
Numerous reports have been received by the Food Agency on the death of wild birds recently, especially on gray geese in the capital. Bird flu H5N5 was diagnosed this week in elves and gray geese.
The Food and Drug Administration recommends that people try to prevent their cats from coming into contact with birds.
On January 22nd, MAST announced the detection of H5N1 in a captive wild mink, along with more die offs in wild birds.
News - 22.01.2025
Bird flu H5N5 is still detected in wild birds and the UI Experimental Pathology that Keldum has now also confirmed the analysis of the virus in a mink found dead in the Reykjavik Aquarius on January 17. No new cases have been detected in cats or other mammals.
The Food Agency is received every day numerous reports of wild bird death. Samples are taken for research in the case of birds of regions or of species not previously identified by the virus.
After studies of samples from a number of gray goose confirmed bird flu, it is assumed that there is an overwhelming likelihood that gray geese found dead in the metropolitan area have been killed due to avian influenza and therefore no longer sampled. The Food Agency, in collaboration with the Reykjavik Animal Service, estimates that approx. 150 carcasses of gray goose have been found since the beginning of the year in Reykjavik, and since last week also elsewhere in the metropolitan area.
When bird flu H5N5 was introduced on a turkey farm in December, various measures were ordered. These included the killing of all birds in the house in question, strict transport restrictions in a specific area of the environment, increased quarantine, surveillance, cleaning and disinfection. The measures managed to prevent further spread of the virus among poultry.
Based on the machine translation of these, it appears that Iceland's MAST are only reporting two cats infected with the H5N5 virus. But, in the first case, two other cats from the same litter died, and were not tested, which is apparently why WOAH is reporting 4 cats infected.
In addition to Iceland, H5N5 reports have been filed with WOAH from the UK, Norway, Germany, and Greenland.
Canada's most recent report was December 23rd. So far, the United States has yet to report this subtype.
While I'm not expecting a shifting away from H5N1 anytime soon, it isn't beyond the realm of possibility that a new subtype - H5N5, H5N2, H5N6 or some other n-type - could emerge and give it a run for its money.
As a segmented virus with 8 largely interchangeable parts, the flu virus is like a viral LEGO (TM) set which allows for the creation of new subtypes or genotypes. Each gene segment can host multiple unique amino acid changes (e.g. HA-Q226L, PB2-E627K, etc) that can alter the behavior - and host range - of the virus.
All reasons why we shouldn't be surprised when the flu does the unexpected.
