Influenza is a enveloped virus made up of single stranded segmented RNA

Influenza virus infection

1. involves binding of hemagglutanin to sialic acid residues on the surface of the host cell, results in engulfement of the virus into the cell via endocytosis
2. The membrane protein M2 forms pH channels that allow protons to move through the viral envelope and acidify the core of the virus causing release of the viral RNA and proteins which are then transported into the host cell nucleus
3. In the nucleus - viral RNA into mRNA
4. viral mRNA translated into proteins in ribosomes
5. Once synthesised haemogglutinin and neuroaminidase glycoproteins are secreted by golgi apparatus onto the cell surface where they fuse with the cell membrane, other viral proteins go back to the host cell nucleus where they assemble newly replicated genomes
6. Assembled viral capsids head to the cell membrane where they leave, taking a segment of the membrane containing the haemogglutinin and the neuroaminidase and thus forming a viral particle
7. The viral neuroaminidase enzyme of this new cell cleaves and removes sialic acid receptors from the surface of this cell allowing release and spread of this virus to a new cell

Classes of drugs

Neuraminidase cleaves sialic acid to allow release of virus, neuroaminidase inhibtors stop this process - oseltamivir