took 15 years. >> nearly all previous outbreaks of emerging infectious agents from arisen through natural means. second, this virus does appear to be related to bat coronaviruses. >> but just how closely related is a critical question. this coronavirus is 96% similar to another virus found in bats. >> it's not close enough to say that it's the exact virus that gave rise to this one in a simple evolutionary step. but that kind of gap, 4%, means years, means decades in terms of natural evolutionary time. >> and that evolution means something. typically, after a virus makes the jump from animal to human, it sputters along, evolving, learning how to become more efficient.