Barack Obama and the head of the CDC need to quit saying that we know exactly how Ebola spreads. Because the truth is that there is much about this virus that we simply do not know. For example, a top Ebola scientist that is working in the heart of the outbreak in Liberia says that this version of Ebola looks like it could be "a very different bug" from past versions. Other leading scientists are echoing his concerns. And yet Barack Obama and Thomas Frieden continue to publicly proclaim that we know precisely how this virus behaves. Not only is...