No one has addressed the “when” in the course of the disease, is the most infective stage.
Most of those returning from Africa were treating very ill patients, those close to death. Would the likely hood of airborne transmittal be greater at this time?
Compare to someone infected who is just now coming down with some symptoms. There seems to be no one infected from Duncan’s early stages, but rather the later stages.
I have a healthy skepticism of studies, particularly those that are not reproduced in controlled settings. I do not think we will know how Ebola behaves in the US until we have gained substantial experience with it through dozens of cases. I hope we do not gain this experience, but I am afraid we might. Until then we have to act with more caution that we think indicated, because we don’t know what we don’t know. Being cavalier about the disease and how its transmitted will come back to bite those who approach it in that fashion. As has already happened at least twice thanks to the CDC