It's a very serious disease.

这是一个非常严重的疾病。

Suppose Britain were afflicted by a serious disease?

假设英国真的受到严重疾病的袭击怎么办？

The poor man has a serious disease of the liver.

这个可怜的人患有严重的肝病。

His father gave up drinking because of serious disease.

他父亲因为重病而不喝酒了。

But it is far from the world's most serious disease outbreak.

但是这与世界上最严重的疾病大暴发相比还不算什么。