So What Was OSX/Leap?
If you want to be technical about OSX/Leap, it was both a worm and a trojan horse. It required a user to accept transfer of the file via iChat and then open it. Once opened, it ran in the background on its own like a worm. Whether you want to use this technical terminology or just consider it the first Mac OS X virus is up to you. But in any case, it is not something you want on your Mac or your Mac network. And it illustrates the fact that even if Mac users have enjoyed more than half a decade of freedom from virus threats, the situation can easily change at any time. Also, just because they don’t pose a great threat, there’s no reason to be blasé about macro viruses, either.