than the ones preceding it.

规模变小受害者数量也减少
That's a very different history than the history of bubonic plague.

这和腺鼠疫是完全不同的
How long would an epidemic last?

流行病一般持续多久呢
It would normally last, in a great European city,

一般来说在一个大型欧洲城市
for the length of the warm summer and perhaps the early fall.

大约从夏天到早秋为主要爆发时间
It would then recede and fade away with the onset of cool weather.

接着霍乱就会伴随寒冷的天气消失
Now, why would it fade away?

那么为什么它会消失呢
Well, Robert Koch, who discovered the Vibrio cholerae,

弧菌的发现者罗伯特·科赫
said himself that this was something,

自己也无法解释
a question to which he couldn't give a satisfactory answer.

他无法给出满意的答案
He said that this was one of the great cholera mysteries,

他认为这是霍乱的几个神秘处之一
as he called it.

他自己说到