Mike,
What do you mean by "Avast does not seem to detect the Morphine?
Have you had a specific instance where it was not detected? If so, provide the full virus name and path.
As far as I know, Avast will detect Morphine through the Heuristics scanner.
inthewildteam,
No, it is not just a form of encoding but a true virus.
This is a benign memory resident parasitic polymorphic virus. It hooks INT 21h, and writes itself to the end of COM and EXE files that are executed or opened. While installing a memory resident, the virus also infects the COMMAND.COM file. The virus checks the file names and does not infect the anti-viruses F-PROT, TBAV, SCAN. The virus deletes the anti-virus data files: ANTI-VIR.DAT CHKLIST.MS CHKLIST.CPS ZZ##.IM
I believe that it will not affect Avast.