Influenza a h3

Abstract and Introduction Abstract Influenza A viruses (IAVs) of subtype H3 that infect humans are antigenically divergent from those of birds, horses, and swine. Human immunity against these viruses might be limited, implying potential pandemic risk. To determine human risk, we selected 4 avian, 1 equine, and 3 swine IAVs representing major H3 lineages. We tested serum collected during 2017–2018 from 286 persons in Belgium for hemagglutination inhibiting antibodies and virus neutralizing antibodies against those animal-origin IAVs and tested replication in human airway epithelia. Seroprevalence rates for circulating IAVs from swine in North America were ≥51%, swine in Europe 7%–37%, and birds and equids ≤12%. Replication was efficient for cluster IV-A IAVs from swine in North America and IAVs from swine in Europe, intermediate for IAVs from horses and poultry, and absent for IAVs from wild birds and a novel human-like swine IAV in North America. Public health risk may be highest for swine H3 IAVs. Introduction Influenza A viruses (IAVs) of the H3 subtype are endemic to humans, swine, and wild birds; they also cause outbreaks in horses and are often detected in domestic birds. An H3 IAV that crosses the species barrier from animals to humans can result in a pandemic if the virus carries a hemagglutinin (HA) against which humans lack protective antibodies and the virus readily replicates in and spreads among humans. For example, in 1968, transmission of an IAV with an avian...

Influenza A virus is the only Alphainfluenzavirus of the virus family [ citation needed] H = N = The hemagglutinin is central to the virus's recognizing and binding to target cells, and also to its then infecting the cell with its [ citation needed] Different influenza viruses encode for different hemagglutinin and neuraminidase proteins. For example, the Some variants are identified and named according to the isolate they resemble, thus are presumed to share lineage (example [ citation needed] Variants are sometimes named according to the species (host) in which the strain is endemic or to which it is adapted. The main variants named using this convention are: [ citation needed] • • • • • • Variants have also sometimes been named according to their deadliness in poultry, especially chickens: [ citation needed] • Low pathogenic avian influenza (LPAI) • Highly pathogenic avian influenza (HPAI), also called deadly flu or death flu Most known strains are extinct strains. For example, the annual flu subtype H3N2 no longer contains the strain that caused the [ citation needed] Annual flu [ ] Main article: The annual flu (also called "seasonal flu" or "human flu") in the US "results in approximately 36,000 deaths and more than 200,000 hospitalizations each year. In addition to this human toll, influenza is annually responsible for a total cost of over $10 billion in the U.S." The annually updated, trivalent Measured resistance to the standard antiviral drugs [ citation needed] "...