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''HPAI A/ #H5N1 viruses (lineage 2.3.4.4b) are rapidly invading the #Americas, threatening #wildlife, #poultry, and potentially evolving into next global #pandemic. In November 2022 HPAI arrived in #Peru, triggering massive #pelican and sea lion die-offs. We report #genomic characterization of HPAI/H5N1 in five species of marine mammals and seabirds (dolphins, sea lions, sanderlings, pelicans and cormorants).''

''Peruvian viruses belong to lineage 2.3.4.4b, but they are 4:4 #reassortants where 4 genomic #segments (PA, HA, NA and MP) position within the #Eurasian lineage that initially entered North #America from Eurasia, while the other 4 genomic segments (PB2, PB1, NP and NS) position within the American lineage (clade C) that circulated in North America. ''

''These viruses are rapidly accruing #mutations, including mutations of #concern, that warrant further examination and highlight an urgent need for active local #surveillance to manage #outbreaks and limit #spillover into other species, including #humans.''

''...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. ''

''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.''

''We suspect that direct #HPAI #transmission between #sealions could be occurring, rather than independent #spillovers into sea lions from #avian sources, but additional sequence data and analysis will be required to further characterise mammal-to-mammal transmission.''