病毒是什麼?

What is a virus?

病毒是什麼？

Influenza. Ebola. The common cold. HIV/AIDS. Measles.

流行性感冒，埃博拉病毒，普通感冒，艾滋病毒，麻疹。

Viruses cause these diseases - and many more. Some are serious. Others, not so much. For better or worse, viruses are part of life.

病毒會導致上述疾病，或者更多。有些很嚴重，有些則不然。不論怎樣，病毒都是我們生活中的一部分。

It surprises many people to learn that viruses "live" in us but aren't technically alive. Viruses can replicate only inside the cells of their host. A host can be an animal, plant, bacterium or fungus.

要知道病毒雖然寄居在我們身上並不意味着它就是活的，這可能會令很多人大吃一驚。病毒僅在宿主的細胞內進行復制。它的宿主可能是動物、植物，也可能是細菌、真菌等等。

Viruses are sometimes confused with another family of germs: bacteria. But viruses are much, much smaller. Think of a virus as a tiny package jacketed in a protein covering. Inside is either DNA or RNA. Each molecule serves as an instruction book. Its genetic information provides instructions that tell a cell what to make and when to make it.

通常我們會把病毒與它的另一個家庭成員-細菌混淆，其區別就是病毒小得多多了。病毒身穿蛋白質外套，內含脫氧核糖核酸或核糖核酸。每一個分子充當着一本說明書。其遺傳信息爲細胞提供指導，告訴他們什麼時候該做什麼。

When a virus infects a cell, it sends that cell a simple message: Make more viruses.

當病毒侵入細胞內時，它會給該細胞發送一個簡單的信號：複製更多的病毒！

In that sense, this virus is a hijacker. It breaks into a cell. Then it makes the cell do its bidding. Eventually, that host cell dies, spewing new viruses to attack more cells. That is how viruses sicken a host.

在這個意義上，病毒就變成了一名劫持犯，它闖入細胞，迫使其按指令行事。最終宿主細胞死掉，吐出新病毒攻擊更多細胞，這就是病毒入侵細胞的整個過程。

(By the way, a computer virus isn't a real virus. It's a type of software, meaning computer instructions. Like a real virus, however, a computer virus can infect - and even hijack - its host computer.)

（順便提一下，電腦病毒不是真正的病毒，他是一種軟件，一種計算機指令。然而與真實病菌類似的是，電腦病毒也會入侵主機內部並將其劫持。）

The body can rid itself of many viruses on its own. Other viruses may present too big a challenge. Medicines to treat viruses exist. Called antivirals, they work in different ways. Some, for example, block the entry of a virus into a host cell. Others interrupt the virus as it attempts to copy itself.

身體可以自行清除許多病毒，但有些病毒表現的像一個巨大挑戰。能對抗病毒的藥物是存在的，叫做抗病毒藥。他們以不同的方式起作用，比如有的會阻止病毒侵入宿主細胞內。有的會中斷病毒複製。

In general, viruses can be hard to treat. That's because they live inside your cells, which shelter them from medicines. (It's also important to note that antibiotics don't work on viruses.)

總之，病毒很難對付，那是因爲它們寄生在你的細胞內部，增加了藥物使用困難。（還需注意的是抗生素可能不會對病毒起什麼作用）