honestly i don't think anyone will going to waste time on writing a virus targeting linux. less than 1% use linux, it won't deal enough damage to the community as a whole.
I'd like to see where you got those statistics, I find them very amusing.
Anyway people have written a few worms for Linux attacking a few exploits in bind, lpd and a some other things but they had little to no effect because the admins of the Linux boxes know how to patch their boxes correctly.
and i believe computer professional don't use antivirus software anyway
If you're a computer professional running Windows and you don't run an antivirus you're an idiot.