How about animals as carriers? Pets? Mosquitoes? Flies? Bugs of all sorts landing on or walking across food or tables or utensils or clothing? IOW no one seems to know anything definitive. Just trust Obama and his cadre of faculty lounge experts to do what is right like they have so reliably in the past. God save the Republic!
Our mobility, hospitable environment, modern conveniences -plumbing, trash pick up, restaurants- and pets really would allow Ebola to flourish and spread.