The question on the DealMac forum: Have you ever caught a Mac virus?
Some long-time users can remember one around 1989-1991 (yes, that is 14 years ago!) but very little since. As for me, I can remember running Disinfectant back in 1990 and it finding the occasional problem, but nothing that caused me to lose any data. Since using OS X full-time since 2001 I haven’t had a single virus, trojan or piece of spyware.