美国国家公共电台 NPR How Zika Became So Dangerous For Babies

 

AILSA CHANG, HOST:

Scientists say they have solved a mystery about the Zika virus. They think they've figured out why the virus became a global threat all of a sudden and started causing severe birth defects. As NPR's Michaeleen Doucleff reports, the study shows how quickly viruses can become extremely dangerous.

MICHAELEEN DOUCLEFF, BYLINE¹: When I received the study, I sent it to a biologist at UC San Diego who's at the forefront of Zika research. His name is Alysson Muotri, and he almost couldn't believe his eyes.

ALYSSON MUOTRI: When you sent it to me, I started reading. I said, oh, my gosh, that's amazing.

DOUCLEFF: Amazing because the study suggests something unexpected. One small change in Zika's genes² made it a big threat for pregnant women. For decades, Zika had been a relatively³ harmless virus that causes only mild symptoms. But then in 2015, it began causing a severe type of birth defect called microcephaly in which babies are born with very small heads. Now researchers at the Chinese Academy of Sciences in Beijing say they know why. Zika mutated. The virus picked up one mutation⁴ that dramatically increased its ability to infect fetal brains.

MUOTRI: That single mutation can actually lead to more severe cases of microcephaly, more severe damage in the fetal brain.

DOUCLEFF: This almost sounds like the nightmare scenario⁵, the virus mutating and becoming this very scary thing. Is this common?

MUOTRI: It is common. It happens all the time. Actually, there are several human disorders⁶ that's caused by a single mutation. So this happens all the time.

DOUCLEFF: But there are caveats⁸ to this study. Hongjun Song is a neuroscientist at the University of Pennsylvania. He says the big caveat⁷ is the experiments were performed in mice.

HONGJUN SONG: Mouse is the one model we have now to test the toxicity⁹ of the virus in animals, which is the best you can do because we can't really do that in humans.

DOUCLEFF: And the study, which appears in the journal Science, doesn't rule out the possibility that other factors - other mutations or something in the environment - made the virus even worse in South America. Nevertheless, Song says the findings are a bit foreboding.

SONG: I think it's just a little bit scary, right? So basically one unlucky change which happens all the time can cause very big, unlucky events down the road. So I think the lesson, I feel, is we all need to be prepared.

DOUCLEFF: Because the next big outbreak is likely just around the corner. Michaeleen Doucleff, NPR News.

(SOUNDBITE OF EMUNE AND MUJO'S "DETROIT STREETS")

1 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

2 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

3 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

4 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

5 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。

6 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

7 caveat   

n.警告； 防止误解的说明

参考例句：

• I would offer a caveat for those who want to join me in the dual calling.为防止发生误解，我想对那些想要步我后尘的人提出警告。
• As I have written before,that's quite a caveat.正如我以前所写，那确实是个警告。

8 caveats   

警告

参考例句：

• I would offer a caveat for those who want to join me in the dual calling. 为防止发生误解，我想对那些想要步我后尘的人提出警告。 来自辞典例句
• As I have written before, that's quite a caveat. 正如我以前所写，那确实是个警告。 来自互联网

9 toxicity   

n.毒性，毒力

参考例句：

• The hoarse grunt or squeal is characteristic of toxicity.嘶哑的哼声和叫声是中毒的特征。
• Dieldrin is related to aldrin,and its toxicity to earthworms is similar.狄氏剂与艾氏剂有关，对蚯蚓的毒性是相似的。