"The Mac has been virtually "virus-free" until recently but new viruses and the resulting precautions have now entered the "Mac World" (PC users have had these problems for years)."

Disinfectant 3.7.1 is the last version of the tool that has been enough for years to protect Mac users from dreaded viruses. Read the message by the author of Disinfectant to see why.

Viruses now need to be consider on the Macintosh. Mac Viruses. Which antivirus program?

Commercial Virus Programs should now be on every Mac computer for the necessary protection. Keep the programs updated!! Read this article from Mac Intouch for more information.

Dr. Solomon's AntiVirus Toolkit for Macintosh
NAV Norton AntiVirus for Macintosh
Symantic (Norton) AntiVirus for Macintosh
Virex for the Macintosh
AntiVirus Resources

TechNotes had a good article on computer viruses which is recommended reading: Tech Notes