Thread by @ejustin46

𝗛5𝗡1 𝗟𝗔𝗦𝗧 𝗨𝗣𝗗𝗔𝗧𝗘 !
(🧵 𝘗𝘈𝘙𝘛 2)
"𝘗𝘳𝘦𝘭𝘪𝘮𝘪𝘯𝘢𝘳𝘺 𝘳𝘦𝘱𝘰𝘳𝘵 𝘰𝘯 𝘨𝘦𝘯𝘰𝘮𝘪𝘤 𝘦𝘱𝘪𝘥𝘦𝘮𝘪𝘰𝘭𝘰𝘨𝘺 𝘰𝘧 𝘵𝘩𝘦 2024 𝘏5𝘕1 𝘪𝘯𝘧𝘭𝘶𝘦𝘯𝘻𝘢 𝘈 𝘷𝘪𝘳𝘶𝘴 𝘰𝘶𝘵𝘣𝘳𝘦𝘢𝘬 𝘪𝘯 𝘜.𝘚. 𝘤𝘢𝘵𝘵𝘭𝘦 (𝘱𝘢𝘳𝘵 2)"
virological.org/t/preliminary-…

2) The original cattle H5N1 virus's hemagglutinin (HA) protein was not adapted to bind to human-like receptors. The closest-related sequences to the cattle H5N1 HA came from wild birds, indicating no pre-adaptation to mammalian receptors.

3) Mutations in HA and the polymerase have been observed in small clades from cattle and cats, but their significance is unclear. Without changes in HA affecting receptor binding, the risk of human transmission is low.
H5N1 has transmitted from cattle to wild birds, poultry ...

4) ...cats, and other species. Sequences from various hosts are nested within the cattle clade, suggesting spillback from cows. Spillbacks to domestic cats have occurred, likely due to raw milk consumption.

5) The tMRCA of the cattle clade and the human virus is estimated to be November 2023. The human sequence has unique amino acid changes not found in cattle or basal avian/wildlife sequences.
The transmission chain is unclear, but a direct avian spillover is unlikely.

6) Mutational signatures support sustained transmission within cattle, with elevated T-to-C mutations in mammals. The mutational spectrum of the cattle outbreak indicates transmission among mammals.
The mutations are more likely to have been generated under the mammal spectrum.

7) Overall, cattle H5N1 has the potential to transmit to other species, including humans, but sustained human transmission risk is currently low.

Thanks for reading 🙏
3rd part soon ...