Hello,
Virus naming coventions are different from company to company.
For Symantec, check these Articles:
Naming convention for statically named virus definition update files
http://www.symantec.com/docs/TECH161663
Virus Naming Conventions
http://www.symantec.com/security_response/virusnaming.jsp
When there is a Virus detected by Symantec, the Symantec website gives more insight / write up on what would be other Antivirus companies be calling the same detection as.
For example:
Infostealer.Dexter
http://www.symantec.com/security_response/writeup.jsp?docid=2012-121219-2643-99
states
Also Known As: BKDR_DEXTR.A [Trend]
Secondly, check this Whitepaper -
What’s in a Name?
By Sarah Gordon,
Senior Research Fellow Symantec Security Response
http://www.symantec.com/avcenter/reference/whatsinaname.pdf
Hope that helps!!