The sky is once again falling for Mac users, with many now hit by the Flashback Trojan. The BBC reports that 600,000 Macs might be infected! But that also happens to be a figure well shy of the number of viruses that can screw up Windows PCs.

Ultimately, infection from viruses and malware continues to be a numbers game. Such things are extremely rare on the Mac but less so on Windows. Apple has since released a security update, but once again an antivirus company started stiring:

“People used to say that Apple computers, unlike Windows PCs, can’t ever be infected—but it’s a myth,” said Timur Tsoriev, an analyst at Kaspersky Lab.

I don’t recall ‘people’ ever saying Apple computers can’t ever be infected—that is the myth. And, of course, Kaspersky Lab would be thrilled if millions of spooked Mac users suddenly started using its products. But the reality is that even those Mac users who don’t have a clue about security will be less likely to be affected by trojans, malware and viruses than their Windows PC-owning chums, and with Gatekeeper for OS X Mountain Lion, such problems will become even rarer on the platform. It’ll be interesting to see if Microsoft follows suit.

As ever, the best advice—on Mac and PC—remains the same: don’t open documents and files if you aren’t confident about where they came from and that they won’t screw up your computer.