© 2016, American Society for Microbiology.The neuraminidase stalk of the newly emerged H7N9 influenza virus possesses a 5-amino-acid deletion. This study focuses on characterizing the biological functions of H7N9 with varied neuraminidase stalk lengths. Results indicate that the 5-amino-acid deletion had no impact on virus infectivity or replication in vitro or in vivo compared to that of a virus with a full-length stalk, but enhanced virulence in mice was observed for H7N9 encoding a 19-to 20-amino-acid deletion, suggesting that N9 stalk length impacts virulence in mammals, as N1 stalk length does.
Bi, Y., Xiao, H., Chen, Q., Wu, Y., Fu, L., Quan, C., ... Gao, G. (2015). Changes in the length of the neuraminidase stalk region impact H7N9 virulence in mice. Journal of Virology, 90(4), 2142-2149. https://doi.org/10.1128/JVI.02553-15