including degrading cellular mRNA and using the released nucleotides for vRNA synthesis and also inhibiting translation of host cell mRNAs.

Negative-sense vRNAs that form the genomes of future viruses, RNA-dependent RNA polymerase, and other viral proteins are assembled into a virion. HA and neuraminidase molecules cluster into a bulge in the cell membrane. The vRNA and viral core proteins leave the nucleus and enter this membrane protrusion (stage 6). The mature virus buds off from the cell in a sphere of host phospholipid membrane, acquiring HA and neuraminidase with this membrane coat (stage 7). As before, the viruses adhere to the cell through hemagglutinin; the mature viruses detach once their neuraminidase has cleaved sialic acid residues from the host cell. Drugs that inhibit neuraminidase, such as oseltamivir, therefore prevent the release of new infectious viruses and halt viral replication. After the release of new influenza viruses, the host cell dies (Figure WO-1).

FIGURE WO-1 Host cell invasion and replication by the influenza virus. The steps in this process are discussed in the text.

SOURCE: Wikipedia (2007 [figure], 2009 [text]).