As far as if ebola can get TO the western world, that is a 100% chance that it can. Primarily, because there is always an underground movement of goods and people, often women and children into and out of countries, regardless of official lockdowns. Think of it like drugs in prisons. There should be no place more free of drugs and alcohol, and yet it's easier to get drugs in prison than in my town. The conversation then is about the remaining requirements to 'spread'.
When we take a look at spreading of other lifeforms, say for instance seeds in Darwin's Origin of Species, dispersal is only a tiny part of the equation with spread being about not just buoyancy, but rather length of sustainability once the seed arrives at a barren landmass.
This is again consistent with man and Mars. We've gone there with robots, and will one day go there with people, but until we establish a foothold, we have not yet spread to Mars.
Regardless of whether the article addresses the point and only the question, all examples of life (and disputed forms of life in the form of virus), do not spread unless they take root.