Figure 3个  Table 4个
    • Gene Site Effect Number
      HA (H3 number) PEIPKG↓GLF Multiple consecutive basic amino acids are a typical feature of highly pathogenic avian influenza 3
      PEVPKG↓GLF 1
      PEVPKRKRTAR↓GLF 14
      PEVPKGKRTAR↓GLF 2
      T160A Enhance the ability of the virus to bind to SAα2-6 Gal receptor 13
      G186V 19
      G186A 1
      Q226L 3
      NA (N2 number) H276Y Resistance to neuraminic acid inhibitors 20
      R292K 2
      Stalk deletion (69–73) Increase replication and virulence in mammals 20
      M2 S31N Resistance to M2 ion channel blockers 20
      PB2 A588V Increased adaptability and virulence to mice 6
      E627K Enhance virus replication 20
      D701N Enhance adaptability in mammals 20

      Table 1.  Statistics of key sites found in the 20 H7N9 strains

    • The nucleotide substitution rate of the HA genes (site/year)
      First wave Second wave Third wave Forth wave Fifth wave
      Time -2013 2013 ~ 2014 2014 ~ 2015 2015–2016 2016–2017 2018–2019
      Rate 5.755E-3 5.734E-3 3.807E-3 1.821E-3 1.917E-3 1.963E-2
      95% 3.85–7.77 (E-3) 3.98–7.71 (E-3) 1.72–6.28 (E-3) 5.27E-5–3.67E-3 2.92E-4–3.60E-3 8.65E-3–3E-2

      Table 2.  HA nucleotide substitution rate

    • Codon nucleotide mutation rate
      First wave Second wave Third wave Forth wave Fifth wave
      -2013 2013–2014 2014–2015 2015–2016 2016-2017 2018 ~ 2019
      First nucleotide 0.354 0.614 0.71 0.603 0.695 0.939
      Second nucleotide 0.248 0.575 0.574 0.413 0.379 0.518
      Third nucleotide 2.398 1.811 1.716 1.984 1.926 1.544

      Table 3.  Codon nucleotide mutation rate

    • Antigen Antiserum (log2)
      H7-Re1 H7-Re2 H7-Re3 rLN79
      H7-Re1 9 12 9 10
      H7-Re2 10 11 8 8
      H7-Re3 3 6 10 10
      rLN79 4 6 10 10
      E65(2017) 7 8 9 9
      E112(2017) 8 8 9 9
      E122(2017) 5 6 8 9
      E128(2017) 8 8 9 10
      E194(2017) 5 9 8 10
      E282(2017) 6 6 9 10
      E594(2017) 5 6 8 10
      E656(2017) 5 6 10 9
      E664(2017) 6 8 9 9
      E743(2017) 6 8 9 10
      F11(2017) 4 9 9 10
      F450(2018) 4 8 9 9
      F690(2018) 5 9 10 10
      F691(2018) 5 9 10 9
      F692(2018) 5 9 10 10
      G285(2019) 4 9 10 10
      G323(2019) 5 6 9 10
      G375(2019) 4 6 9 9
      G502(2019) 3 6 10 10
      G503(2019) 3 6 9 10

      Table 4.  Hemagglutination inhibition endpoint titers of 20 influenza virus subtype H7N9 strains