But those viruses were for Mac OS 9 and earlier operating systems that were discontinued years ago. There have been zero viruses in the wild for Mac OS X since it was introduced five years ago.
The vast majority of Mac OS X users don't even have anti-virus software. In the Windows world, they would be sitting ducks.
those viruses were for Mac OS 9BTW, I've been running just Macs for a long while now, and have never moved to OS X, and have never had a virus.