Spillover: Zika, Ebola, and Beyond

Zika and Ebola—like rabies, dengue, and other killer viruses—reside in animals and spill over into humans. Today, spillover diseases are more common, and we are more vulnerable. Now, scientists are on the hunt for deadly diseases, hoping to stop them before they spill over and spread out of control. It's not a question of if another outbreak will strike, but when? And will we be prepared?