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Emerging H5N8 avian influenza viruses See all authors and affiliations
Science 21 May 2021:
Vol. 372, Issue 6544, pp. 784-786
DOI: 10.1126/science.abg6302
The first confirmed outbreak of highly pathogenic avian influenza virus (HPAIV) in birds was documented in Scotland in 1959 with the influenza A H5N1 subtype, although there have been numerous suspected HPAIV outbreaks documented globally since 1878. H5N1 and its genetic reassortants (including H5N2, H5N5, H5N6, and H5N8) have been found to cause thousands of outbreaks worldwide (1, 2) in both farmed poultry and wild birds, with massive mortality. The H5Ny HPAIVs are lethal to most farmed poultry, and culling is often used to prevent further spread. Several of the H5Ny AIVs have zoonotic and pandemic potential because they have been demonstrated to cross the species barrier, transmitting to mammals, including humans. Eurasia and Africa are experiencing a new wave of highly pathogenic H5Ny AIV outbreaks. The zoonotic potential of AIVs warrants continuous, vigilant monitoring to avert further spillovers that could result in disastrous pandemics.
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The affected geographic regions have been expanding continuously, and at least 46 countries have reported highly pathogenic H5N8 AIV outbreaks. In addition, the HA protein of these H5N8 AIVs harbors several amino acid substitutions of concern, including Thr[SUP]160[/SUP]?Ala (T160A, H3 numbering), which has been reported to enhance the binding capacity to ?-2,6 sialic acid receptors that are favored by human influenza viruses (14). The first human cases of H5N8 influenza virus infection were reported in Russia in December 2020: Seven poultry farm workers tested positive when they participated in a response operation to contain an H5N8 AIV outbreak (15). Phylogenetic analysis revealed that the H5N8 virus sequenced from the human cases also belonged to clade 2.3.4.4b of the H5 phylogeny. Therefore, the global spread of AIVs, particularly the H5N8 subtype, has become a major concern to poultry farming and wildlife security but, critically, also to global public health.
Because of the long-distance migration of wild birds, the innate capacity for reassortment of AIVs, the increased human-type receptor binding capability, and the constant antigenic variation of HPAIVs, it is imperative that the global spread and potential risk of H5N8 AIVs to poultry farming, avian wildlife, and global public health are not ignored.
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https://science.sciencemag.org/content/372/6544/784
Emerging H5N8 avian influenza viruses See all authors and affiliations
Science 21 May 2021:
Vol. 372, Issue 6544, pp. 784-786
DOI: 10.1126/science.abg6302
The first confirmed outbreak of highly pathogenic avian influenza virus (HPAIV) in birds was documented in Scotland in 1959 with the influenza A H5N1 subtype, although there have been numerous suspected HPAIV outbreaks documented globally since 1878. H5N1 and its genetic reassortants (including H5N2, H5N5, H5N6, and H5N8) have been found to cause thousands of outbreaks worldwide (1, 2) in both farmed poultry and wild birds, with massive mortality. The H5Ny HPAIVs are lethal to most farmed poultry, and culling is often used to prevent further spread. Several of the H5Ny AIVs have zoonotic and pandemic potential because they have been demonstrated to cross the species barrier, transmitting to mammals, including humans. Eurasia and Africa are experiencing a new wave of highly pathogenic H5Ny AIV outbreaks. The zoonotic potential of AIVs warrants continuous, vigilant monitoring to avert further spillovers that could result in disastrous pandemics.
...
The affected geographic regions have been expanding continuously, and at least 46 countries have reported highly pathogenic H5N8 AIV outbreaks. In addition, the HA protein of these H5N8 AIVs harbors several amino acid substitutions of concern, including Thr[SUP]160[/SUP]?Ala (T160A, H3 numbering), which has been reported to enhance the binding capacity to ?-2,6 sialic acid receptors that are favored by human influenza viruses (14). The first human cases of H5N8 influenza virus infection were reported in Russia in December 2020: Seven poultry farm workers tested positive when they participated in a response operation to contain an H5N8 AIV outbreak (15). Phylogenetic analysis revealed that the H5N8 virus sequenced from the human cases also belonged to clade 2.3.4.4b of the H5 phylogeny. Therefore, the global spread of AIVs, particularly the H5N8 subtype, has become a major concern to poultry farming and wildlife security but, critically, also to global public health.
Because of the long-distance migration of wild birds, the innate capacity for reassortment of AIVs, the increased human-type receptor binding capability, and the constant antigenic variation of HPAIVs, it is imperative that the global spread and potential risk of H5N8 AIVs to poultry farming, avian wildlife, and global public health are not ignored.
...
https://science.sciencemag.org/content/372/6544/784