Hard to say. Most hospitals are not prepared for (and don't expect) a disease like Ebola to walk through the door. So while we have much better standards of cleanliness and isolation than a hospital in sub-saharan Africa, we're still likely to be taken by surprise by a patient who presents with a bad fever.

The worst case is that someone gets infected and flies to a major city before they get really sick. You could have a huge network of transmission before it ever hits a hospital.