Mac users have generally had less to worry about on the virus front than their Windows using counterparts, but there are still a fairly large number of Mac OS viruses floating around the Internet. Brought to attention by the latest "Simpsons" virus, Mac viruses can still cause major problems for those not aware of their presence or protected from their existence. For those interested in a description of most of the known Mac viruses, the SecurityPortal Web site is where to find that information.
Containing detailed descriptions of over 100 known Mac related viruses, the SecurityPortal Web site is a great place to start for anybody interested in the security of their system. According to SecurityPortal:
The malware listed below is specific to the Macintosh operating system. This list does not include macro viruses, which have the capability of proliferating in both Macintosh and PC operating systems.
You can find more information at the SecurityPortal Web site.