Three classes of anti-influenza drugs have been used for chemoprophylaxis and treatment of influenza virus infections [8] (Figure 1): amantadine (1) and rimantadine (2) which inhibit viral membrane protein (M2) of the proton channel that is necessary for uncoating; oseltamivir (3), zanamivir (4), peramivir (5) and laninamivir octanoate (6) which inhibit viral neuraminidase (NA) that is necessary for virion release and ribavirin (7) that inhibits enzyme activity essential for viral replication. The gene discussed is XK; the disease is influenza.