Introduction: Because influenza infection of ostrich and emu can lead to the selection of PB2-E267K and PB2-D701N mutants and because ratite-origin influenza isolates of low pathogenicity can easily be converted to a highly pathogenic avian influenza virus in chickens, meticulous care must be taken to prevent the spread of nH7N9 to ostrich and other members of the Ratitae family.

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Introduction: The control of a human nH7N9 outbreak may prevent further adaptation of nH7N9 in humans because PB2-E267K and PB2-D701N mutants can be selected during replication in humans.

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