If the virus had been capable of spreading through the air, or if one infected person had unknowingly entered a large population center, Ebola might have become a worldwide epidemic.

如果这种病毒能够通过空气传播，或者如果一名感染者在不知情的情况下进入了人口密集的地区，那么埃博拉可能已经成为一种全球流行病。