OS 10.6.7
While running the latest update of VirusBarrier 6, I got a positive for OSXBlackCat.gen exploit. Which seems to be RansomWear
http://www.iphonegeek.com/ios/102-intego-actual-mac-threats-still-rare-trickware.html

I've been aware of a couple of mac viruses for awhile now but they involved you putting your admin password in to install, personally I don't consider giving permission to something a virus. I do know that right now there is something with google images I clicked on a pic and up popped a windows XP system scan saying I was infected it then asked for my password, which I did NOT give. I scanned with Norton and clamx neither found an infection. Any idea how you got this? If you weren't asked for your password thats scary.

I use MacScan to check for and remove tracking cookies. Also I never activated it. I think it was a partial

http://support.apple.com/kb/HT4650

and

http://reviews.cnet.com/8301-13727_7-20066173-263.html

'm running Sophos Anti-Virus live scan on my Mail and Downloads. It is finding an increase of malware in my junk folders
I think anyone not using an anti-virus should start
I think Mac's are losing their immunity

are these false positives? I'm not getting any of these but you may be right about losing the immunity

No. Some are repeaters. All spam