So about three billion years ago, bacteria evolved a defense mechanism to fight viral infection.

所以大约30亿年前，细菌进化出一种防御机制来对抗病毒感染。

And pneumonia, often triggered by bacterial or viral infections, attacks the alveoli themselves.

肺炎——常常由细菌或病毒感染引发——会攻击肺泡本身。

Those are caused by a viral infection.

由病毒引起。

Fever and muscle aches are common symptoms for a viral infection.

发烧和肌肉疼痛是病毒感染的常见症状。

Viral infection is triggered by a common parasite, the Varroa mite, that spreads rapidly in beehives.

病毒传播是由一种常见的寄生虫虱引发的，这种寄生虫巢里很快传播开来。

It's now semi-paralyzed, possibly due to a viral infection the wasp gave it.

瓢虫处于状态，可源自黄造成的病毒感染。

The viral infection can be serious for small children.

这种病毒感染对幼儿可造成严重影响。

It can be caused by a viral infection or just from yelling too much.

这可是由病毒感染引起的，或者只是因为大喊大叫得太多了。

Another clue is that an individual's response to viral and bacterial infections might be involved.

另外，个体对病毒和细菌感染的反应可也牵涉其中。

When the cause is identified, it's usually a viral infection, like Coxsackie B virus.

急性心包炎的已知病因通常是病毒感染，如柯萨奇B组病毒。

The veterinarian said a viral infection caused the marmot's abnormal behavior.

兽医说，病毒感染导致了土拨鼠的异常行为。

And die a slow, agonizing death From a viral infection than work with you.

抑或是染上病毒痛苦而挣扎着死掉也不要和你一起工作。

It is a mosquito-borne viral infection that causes flu-like symptoms.

它是一种通过蚊子传播的病毒性感染，会引起类似流感的症状。

The best way to prevent the spread of a viral infection is to have a vaccine.

预防病毒感染传播的最好方法就是接种疫苗。

Many had a higher than normal body temperature and what seemed like a common viral infection.

许多人的体温高于正常体温，这似乎是一种常见的病毒感染。

It is an inflammatory problem that affects the spinal cord and is often started by viral infections.

这是一种影响脊髓的炎症，通常是由病毒感染引起的。

In the early days, antibiotics were heavily overprescribed, including for viral infections they had no effect on.

早期，抗生素处方严重过量，甚至被用毫无疗效的病毒感染上。

Measles is a viral infection that is serious for small children but is easily preventable by a vaccine.

疹是一种病毒性传染病，这种传染病对幼儿来说很严重，但却很容易通过疫苗预防。

Hepatitis C is a serious viral infection that can cause liver damage and even liver cancer, if left untreated.

丙肝为病毒性传染性疾病，若不及时治疗，它将对肝脏造成损坏，甚至引发肝癌。

Other events, like warming oceans and heat waves, spoil seafood and droughts bring bats carrying viral infections to people.

其他事件，如海洋变暖和热浪会使海鲜变质，干旱会把携带传染病病毒的蝙蝠带给人类。