It looks like some westerners are starting to panic, so here are some soothing words: if Ebola ever did reach a western country, it wouldn't actually be that hard to contain. Modern medical systems know how to handle Ebola pretty well, despite the fact that there is no proven cure or vaccine. Helping those who have contracted the disease is very difficult, but containing it before all hell breaks loose is entirely feasible.
The reason that containment is failing miserably in Africa is because the public health systems in countries like Liberia and Sierra Leone are, well, miserable. If you're in Africa, you should be worried. Otherwise, please go back to your first world problems...