Apple does its job to make sure that you'll see more viruses on Windows than on a Macintosh.
My favourite quote – "As you might imagine, we are upset at Windows for not being more hardy against such viruses, and even more upset with ourselves for not catching it."
According to McAfee, this virus infects due to a user's insertion of a removable drive carrying the virus, and "the user agrees to the auto run prompt for execution of the worm".
Uh.. so I guess that line should be "As you might imagine, we are upset at Windows for automatically running the software we approve it to run, and even more upset with ourselves for distributing it through shoddy practices and a lack of scanning or clean-room preparation of these devices."
At least Apple isn't asking for access to patch the Windows kernel.