It's already capable of infecting humans with fair ease. Not too easily, but it's just a matter of time before that change occures. Some strains are now touch and close-quarters communicable (aka- you can spread it by coughing on someone). As opposed to less than a year ago when you practically had to bite the heads off of infected chickens. At this rate, we get another six months to a year, and it'll spread as quickly as any human influenza virus.
EDIT: and that assumes we don't have some psychotic terrorist grab ahold of the stuff and play with it. It's not too hard to "breed" virus strains to merge their abilities. Doing it without accidentally exposing yourself: that's the trick.
