The first variant of this virus appears to have been written to force TBScan to use the DOS file system and ignore the contents of Anti-vir.dat. It is also known as the "Thunderbyte Killer" due to the text "The Rise and Fall of Thunderbyte-1994-Australia. You Will Never Trust Anti-Virus Software Again!!", but it also attempts to avoid detection by F-Secure anti-virus products and Norton Antivirus.
Lemming has been reported to be widespread in Australia.
There are few known variants.
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.