David Quammen talks about his latest book, Spillover: Animal Infections and the Next Human Pandemic . From his Web site : "The next big and murderous human pandemic, the one that kills us in millions, will be caused by a new disease--new to humans, anyway. The bug that's responsible will be strange, unfamiliar, but it won't come from outer space. Odds are that the killer pathogen--most likely a virus--will spill over into humans from a nonhuman animal"