Definitely behaviour that is beneficial to toxoplasma, but absolutely not for the rodent.

绝对是有益于弓的行，但绝对不是啮齿动物。

A similar process happens with toxoplasma and mice which breeds in the digestive system of cats.

类似的过程发生在猫的消化系统中繁殖的弓和上。

We're talking about toxoplasmosis, a disease caused by toxoplasma gondii.

我们说的是弓病，一种由弓引起的疾病。

Regardless, toxoplasma has definitely benefited from humans to become one of the world's most successful parasites.

无论如何， 弓确实受益于人类，成世界上最成功的寄生之一。

There wasn't a good explanation for this until the discovery of the toxoplasma life cycle in cats.

一直以来科学家都没有办法解释何如此，直到我们发现了弓生命周期和猫之间的关联。

This is contrast to marsupials and monkeys in America and Europe who did evolve alongside cats and toxoplasma.

这与生活在欧洲及美洲的有袋动物和猴子成了对比，因它们演化的过程中，一直以来都和猫科动物及弓有所接触。

New research shows that gray wolves get infected with toxoplasma by interacting with cougars and their feces, which carry the parasite.

新的研究表明，灰狼通过与携带寄生的美洲狮及其粪便相互作用而感染弓。

Now, but wait. If animals and humans evolved to prevent susceptibility to toxoplasma, why did DD get it?

等等，回过头来，如果动物和人会演化出抵抗弓的能力，那什麽DD会发病呢？

Like all parasites, toxoplasma lives at the expense of its host, and needs its host to produce offspring.

与所有寄生一样， 弓以宿主代价生存，需要宿主才能产生后代。

As we know it today, toxoplasma gondii is a parasite whose infective life cycle depends on cats.

现今，我们知道，弓这种寄生的生命周期循环必须仰赖猫。

Today, we tell pregnant women not to clean the cat's litterbox, for risk of transmitting toxoplasma to the unborn baby.

现今，我们会告诉怀胎的孕妇避免清理猫砂，以免将弓垂直感染给还在体内的婴儿。

Wolves infected with toxoplasma are more likely to wander away from their former pack to find a new one and are more risk-taking, more bold.

感染弓的狼更有可能离开原来的狼群去寻找新的狼群，而且更冒险，更大胆。

The wolves studied recently in Yellowstone National Park could be drifting near to the source of their infection, cougars, because toxoplasma reproduces only in the stomach of felines.

最近在黄石国家公园被研究的狼可能漂流到它们的感染源美洲狮附近，因弓只在猫科动物的胃里繁殖。

It also slows reactions and decreases concentration, which may be why one study found that people involved in traffic accidents were almost three times more likely to have toxoplasma.

它还会减慢反应并降低注意力，这可能就是什么一项研究发现发生交通事故的人感染弓的可能性几乎高出三倍。

Hep. A may not be a latent infection in the same way that toxoplasma is, but it is another part of the human experience of living in a world where we coexist with microorganisms.

A型肝炎或许不会像弓浆一样变成潜伏的疾病，但却是个人们和微生物共同生活在一起的好例子。