epidemic

1. N-COUNT If there is an epidemic of a particular disease somewhere, it affects a very large number of people there and spreads quickly to other areas. (疾病的) 流行

A flu epidemic is sweeping through Moscow. 一场流感正席卷莫斯科。

2. N-COUNT If an activity that you disapprove of is increasing or spreading rapidly, you can refer to this as an epidemic of that activity. (坏事的) 盛行[表不满]

...an epidemic of serial killings. …连环谋杀的盛行。