Submitted to: Journal of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2009
Publication Date: 5/1/2009
Citation: Matsuoka, Y., Swayne, D.E., Rameix-Welti, M., Naffakh, N., Warnes, C., Altholtz, M., Donis, R., Subbarao, K. 2009. Neuraminidase stalk length and additional glycosylation of the hemagglutinin influence the virulence of influenza H5N1 viruses for mice. Journal of Virology. 83(9):4704-4708.
Interpretive Summary: As avian influenza outbreaks progress, the viruses have changed by adding sugar to the hemagglutinin surface protein and shortening of the surface neuraminidase, but how these effect disease production is unknown. In experimental studies, the shortened neuraminidase made the viruses more deadly for mice, but not for chickens. Extra sugar groups on the hemagglutinin had inconsistent effect on disease production. The short neuraminidase of H5N1 viruses circulating in Asia may contribute to disease production in humans.
Technical Abstract: Following passage of avian influenza H5 and H7 viruses in poultry, the hemagglutinin (HA) can acquire additional glycosylation sites and the neuraminidase (NA) stalk becomes shorter. We investigated whether these features play a role in the pathogenesis of infection in mammalian hosts. From 1996 to 2007, H5N1 viruses with a short NA stalk have become widespread in several avian species. The short stalk NA had higher enzymatic activity than a long NA stalk and the viruses with these NAs were more virulent for mice, but not for chickens. The presence of additional HA glycosylation sites had less of an effect on virulence than NA stalk length. The short stalk NA of H5N1 viruses circulating in Asia may contribute to virulence in humans.