But he could not find a viable human host, Jimmy turned to books.

但他找不到可行的人类宿主，于是吉米开始读书。

Contemporary, 'normal' flu viruses require the presence of the enzyme trypsin in their human host, in order to replicate.

在当代，“正常”流感病毒需要在其人类宿主中有胰蛋白酶才能复制。

Raccoon roundworms are not excreted by their human host.

- 浣熊蛔虫不会被人类宿主排出体外。

So, goodbye for now from your very human host, Ariel Goodbody.

那么，我们的人类主人 Ariel Goodbody 暂时再见了。

And now that Antonia has a human host, well, you can see the result.

眼下安东尼娅拥有了一个活人宿主，后果如何 你可以想象。

It may very well be that some bacteria are completely dependent on their human hosts and thus coevolving with us, whereas others can come and go.

有些细菌很可能完全依赖于人类宿主，继而与我们共同进化，而其他细菌则可以来去自如。”

While a natural measles virus reproduces thousands of times during an infection, a weakened virus can only reproduce about twenty times inside of a human host.

天然麻疹病毒在感染期间可繁殖数千次，而弱化病毒在人类宿主体内只能繁殖约 20 次。

But they don't have the built-in reproductive capacity of bacteria -- tiny, living organisms which, once they have infected a human host, can make copies of themselves using their own DNA.

但它们并不具备细菌那样的内在生殖能力，细菌这样的微小生物一旦感染了人类宿主，就能用自己的DNA复制自我。

With most flaviviruses though, the virus isn't able to replicate enough in the human host to actually be able to reinfect another mosquito, and so the human is considered a dead-end-host.

然而对于大多数黄病毒来说，病毒在人类宿主体内的复制量较低，很难感染另一只蚊子，此时人类就是终端宿主。

So when a mosquito that also happens to be carrying the virus finds her meal and digs in, the virus infects the human host and starts to multiply or reproduce within the human.

所以当一只恰巧携带病毒的蚊子找到食物并进行叮咬，病毒会感染人类宿主并开始在人体内繁殖。

All of the methods that involve passing a virus through a non-human host produce a version of the virus that can still be recognized by the human immune system, but cannot replicate well in a human host.

所有涉及通过非人类宿主传播病毒的方法都会产生一种病毒版本， 该版本仍可被人类免疫系统识别， 但不能在人类宿主中很好地复制。