学习视频：病毒的传播 Learning Video: The Spread of Virus

比如说：人们感染水痘带状疱疹病毒VZV后，浑身上下就会长满小红包，我们称之为“水痘”。水痘会让人奇痒难耐，这都是病毒在作祟。水痘中有更多的病毒，当人们忍不住挠这些水痘时，病毒就会趁机扩散出来，并传播到周围人身上。

这个传播方式真是机智又邪恶，这也是很多病毒在人群中传播的方式。它们先潜入某个机体，几天或者几年后，一有机会，就会潜入另一个机体。从潜入机体到发作并能进行传播之前的这段时间叫做“潜伏期”。这段时间内，病毒会进攻其他细胞并且攻击免疫系统。在潜伏期，你甚至不会发现病毒的存在。感染水痘病毒数周后，第一个水痘才会冒出。

还有另外一种常见病毒，它的潜伏期仅仅只有半天，你想知道这是哪种病毒吗？

请点击下方文字链接观看视频：

学习视频：《病毒的传播》

The varicella-zoster virus vzv causes little red spots to appear all over the infected person, we call them chickenpox. They are very very itchy and the virus did that on purpose. It fills the pox with more viruses, so when people scratch them, they let the virus out of their body, spreading it to people nearby. 

It’s actually pretty smart in an evil way, and this is how lots of viruses move through the population. They get inside a body, and after a few days or sometimes years, they’ll try and hitch a ride to another body. The time from when they get inside a person to when they try and spread is called the incubation period. During that time the virus is invading cells and fighting the immune system. During the incubation period, if you have a virus you might not even notice. Chickenpox can take weeks before the first pox appear. 

There is another common virus that is less patient, of which the incubation period is only half a day. Would you like to know what virus it is?

Please click the link below to watch the video:

Learning Video: The Spread of Virus