It might burn itself out, which is as bad as it sounds - it will kill so many people there will be no one left to infect.
There will probably be mandatory quarantine as well, and everyone inside the zone will either die or become immune.
Or we might figure out how to manufacture the 2 or 3 known cures in great enough quantity.
Or a vaccine - seems to me this should not be a huge challenge to develop a vaccine for because (unlike HIV) people become immune after exposure, which is half the battle already.