As we deforest these viruses' home, wipe out their reservoir hosts, they need a new one to spill over into us. Viruses have been around for billions of years because they're smart. The Ebola virus feeds, and then it retreats back into the shadows, where it learns, mutates. Believe me when I tell you this Monster will be back again. And we need to be ready.
——Dr. Nancy Jaax 《The Hot Zone》