The problem is different.

问题是不一样的
It happens when the Vibrio gets into the soil beneath a major city.

只有当弧菌侵入主要城市的土壤时才危险
And there, Pettenkofer used a horticultural analogy,

这里佩腾科弗使用了园艺中
referring to germination or fermentation.

发芽或发酵的概念作类比
After the Vibrio gained access to the soil,

当弧菌侵入土壤后
under certain conditions it could germinate like a plant and

在特定条件下它可以产生类似植物的东西
give off its poison into the air above,

并通过它释放有毒气体到地表
that the population inhaled, and those who were susceptible

当吸入这些有毒气体时
fell ill in large numbers, and it was then that you'd have

易受感染的人群就会大量生病
the onset of an epidemic.

这就是疫病的爆发
In nineteenth-century medical parlance,

19世纪的医学传统
cholera was an example of a whole category of diseases that

把霍乱被称作发酵病