Drone strikes aren't contagious
They kinda are :-D First by physical proximity at the moment of the strike (you get to be called "collateral damage"), and second, via the "association with suspicious persons" method.
The only way for people in the U.S. (whether they are citizens or not) to be safe from Ebola is for people with Ebola to be prevented from entering
Are you, by any chance, looking for absolute safety? It tends to be very expensive to achieve and even then fails often enough.
If we are talking about "driving the risks from Ebola to the general background risk level", well, at the moment it's well below that level.
driving the risks ... to the general background risk level
IAWYC, but in general the right thing to do is to reduce the risk until the marginal cost of reducing it more exceeds the disutility of what one is risking: for example, if I can spend one cent to reduce the probability I'll die tomorrow by 1e-7 (e.g. by not being as much of a jackass while driving) I should do so, even though the general background risk level (according to actuarial tables for my gender, age and province) is more than an order of magnitude larger.
Another month, another rationality quotes thread. The rules are: