''1 of Arequipa viruses (A/SA sea lion/PeruAQP-SER00R/2023) w/ D701N #mutation clusters on #PB2 tree with #H5N1 isolated from a #human in #Chile a few wks later (3 24, 23) that also has D701N, but this pattern does not hold for trees inferred using other genome segments... these data provide #evidence that D701N is emerging repeatedly in H5N1 viruses that infect mammalian hosts along S America’s Pacific coast... these data cannot yet ascertain if viruses ... are transmitting within mammals.''

''...2 #H5N1 viruses collected from sea lions in south Peru (Arequipa region) during latter phases of outbreak cluster w/ Chilean viruses, reflecting instances of viral gene flow across Peru’s southern border. Both of these viruses have #PB2 D701N mutation that is associated with enhanced mammalian #transmission in mammals, however, these Arequipa viruses were collected in sea lions a month apart (Feb 7, 23 vs. March 6, 23) & they do not cluster together on the same phylogenetic trees. ''

''• #Human-derived #H3N8 viruses replicated efficiently in #human respiratory epithelial cells
''• Human-derived H3N8 viruses caused severe #pathology in mice and #ferrets
''One human H3N8 isolate acquired efficient respiratory #droplet #transmission in ferrets
''•The #PB2-E627K mutation is critical for H3N8 virus airborne transmission in ferrets.''

''Other well characterized #mammalian-adaptive #substitutions such as #PB2 627 K or 701N were not present in the #H5N1 viruses from #Bangladesh, however, they did contain PB2-655 V, which has been shown to act cooperatively to increase viral #polymerase activity in human cells46,47.''

''We also detected a novel clade 2.3.4.4b #H5N1 virus from #ducks in free-range #farms in Tanguar Haor that was similar to viruses first detected in October 2020 in The #Netherlands but with a different #PB2. ''

''Analysed HPAI #H5N1 virus #genomes from #cats are almost identical..., suggesting a monophyletic origin and a potential common source of infection. They all carry #mutations associated with #mammalian #adaptation in #polymerase gene (both #PB2-E627K and PB2-K526R), allowing for replication at lower temperatures. An assessment of both the HA and NA genes found no other changes of concern in the sequenced viruses.''

Key mutations among the #AvianInfluenza sequences isolated from #Cats uploaded to #EpiFlu @gisaid from #Poland | Analysis using #FluServer tool.

Interesting #PB2 mutations: #E627K (Mammalian Adaptation Signature) and #K526R (Enhances E627K)

https://www.cidrap.umn.edu/avian-influenza-bird-flu/polish-officials-probe-h5n1-avian-flu-link-cat-deaths

''E627K and E627V in #PB2 genes were exclusively detected in #human #H3N8 viruses, suggesting #adaptation of these viruses to #mammals.''

{#H5N1} #BirdFlu Sample from #Chile #Man Showed Some Signs of #Adaptation to #Mammals {changes in the #PB2 genes}, https://www.nytimes.com/2023/04/14/science/bird-flu-humans.html

''The XL virus had similar
#mammalian #adaptations to #human-originated #H7N9 viruses, such as the polymerase basic protein 2 (#PB2) Glu-to-Lys mutation at position 627 (#E627K) mutation, but differed from avian-originated H7N9 viruses''

#Minks on a #Spanish #farm infected with an #H5N1 #birdflu strain showing concerning #mammal-adaptation signature {#PB2 sub-unit}, full text: https://balicitizen.com/mink-di-peternakan-spanyol-terinfeksi-flu-burung-dan-potensi-kontaminasi-silang/