Here is a reason not to worry too much about Ebola… yet. I took the WHO data on Ebola outbreaks and plotted it. The distribution is not power-law distributed (looks bent on a loglog scale) but is decently exponential (straight on a semilog scale). The probability goes down fast with size.
However, when we add the final toll from the current outbreak (1603 suspected cases with 887 fatalities at August 1) it might turn out to be a “dragon-king” bucking the line: in that case we should expect that large international outbreaks follow an entirely new dynamic. This is mildly worrying. Still, it is early days.