TABLE 3.

Mutations present in viral sequences on multiple days

MutationMutation seen in epidemiological-scale equine H3N8Amino acid position variable in equine H3N8?Motif locationaSample (dog or virus) with this mutation (day)b
Nucleotide substitutionAmino acid substitution
Synonymous mutations
    T24CN8NYesYes (N, K)8271 (day 2)*, 7151 (day 4)*
    T228CC76CYesYes (C, Y)Challenge virus*, 827 (day 2)*, 7151 (day 3)*
    C231TD77DYesYes (D, N)Challenge virus*, 7151 (day 4)*
    T333CI111INoYes (I.L)7151 (day 2)*, A1100*
    A384TT128TNoNo (T)7151 (day 2)*, 5981 (day 3)*
    A390GV130VNoNo (V)Near Ag A7151 (day 3)*, 7151 (day 4)***
    T435CD145DYesYes (D, S)Ag A7151 (day 4)*, 6685 (day 3)*
    T663GP221PNoNo (P)7151 (day 4)***, 6685 (day 2)*
    A681GS227SNoYes (S, P)Challenge virus*, 8271 (day 2)*, 8271 (day 4)*
    G762TP254PNoNo (P)7151 (day 4)***, 6685 (day 2)*
Nonsynonymous mutations
    G87AM29INoYes (I, L)8271 (day 2)*, 7151 (day 4)*
    G89AS30NNoYes (S, T)Challenge virus**, 7151 (day 4)**
    A95GD32GYesYes (D, G)Challenge virus*, 7151 (day 2)*, 5981 (day 2)*
    A131GQ44RNoNo (Q)8271 (day 4)*, 5981 (day 2)*
    T166CY56HNoNo (Y)Near Ag Ca8271 (day 2)**, 8271 (day 4)*
    G248AS83NYesYes (S, N, K)Ag Eb8271 (day 2)*, 8271 (day 3)*, 8271 (day 4)**, 7151 (day 2)*, 7151 (day 3)****
    G275AS92NYesYes (S, N)8271 (day 4)*, 7151 (day 4)***
    G316AA106TNoNo (T)Near Ag Eb7151 (day 4)*, 5981 (day 3)*
    T332CI111TNoYes (I.L)7151 (day 4)*, 6685 (day 3)*
    G352AV118 MNoNo (L)Near Ag A7151 (day 2)****, 7151 (day 4)**************
    A376GT126AYesYes (T, A, I)Ag BChallenge virus*, 7151 (day 4)*, A1100**
    A466GK156EYesYes (K, E, Q, N)Ag BChallenge virus**, 8271 (day 3)*, 7151 (day 3)****
    A584GY195CNoNo (Y)Stabilizes receptor binding pocket?8271 (day 2)*, 8271 (day 4)*, 5981 (day 3)*
    G653AG218ENoNo (G)Ag DbChallenge virus******, 8271 (day 2)*******, 7151 (day 2)******, 7151 (day 4)*************************, 5981 (day 2)****, 6685 (day 2)**
    A660CR220SNoNo (R)Ag DbChallenge virus**********, 8271 (day 2)****************, 8271 (day 3)****, 8271 (day 4)*********, 7151 (day 2)***********, 7151 (day 3)********, 7151 (day 4)*, 5981 (day 2)******************************, 5981 (day 3)******************************, 6685 (day 2)**
    G686AR229KNoNo (R)Stabilizes receptor binding pocket?8271 (day 2)*, 8271 (day 3)*, 8271 (day 4)*
    T725GI242SNoYes (I, V, T)Ag Dc8271 (day 3)*, 8271 (day 4)*
    C761TP254LNoNo (P)8271 (day 4)*, 7151 (day 4)*
  • a Ag, antigenic site.

  • b The frequency with which the mutation is present in virus from animals or in the challenge virus is indicated by the number of asterisks. The sampling day postinoculation is shown in parentheses.