al reaccidental release from the lab. and spill over. both theories remain viable. now, the question is, will we ever know? it's not easy, if you think about it, tracing the origins of a small strand of genetic material on a massive planet never is. consider that it's been 45 years since the first recognized cases of ebola. yet we're still not sure of its origins. tracing sars to horseshoe bats 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.