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麻疹的传播

Here's What Makes Measles So Dangerous

麻疹是人类已知的最具传染性的疾病之一
Measles is one of the most contagious diseasesknown to man.
如果麻疹病人在电梯里咳嗽
In fact, if someone with measles coughs in an elevator,
同时搭乘此电梯的人
90 % of the people who use that
其中90%会染上麻疹
elevator after will catch the disease.
除非你已注射疫苗
Unless of course you’ve been vaccinated.
那样你就不会有事
Then you’ll be completely fine.
这就是麻疹病毒
This is the measles virus,
它已存在几千年了
it’s been around for thousands of years
已经造成了
and has been responsible for
几百万人死亡
the deaths of millions of people.
嗯 表面上
Now, on the surface,
麻疹的症状似乎不会要人命
measles symptoms seemfairly innocuous.
但是真正的
But the real damage,
危及生命的损害发生在细胞层面
the damage that can lead to death, happens on a cellular level.
大家好 我是Roberto Cattaneo
Hi I’m Roberto Cattaneo.
我是一名哲学博士 也是梅奥诊疗中心的分子生物学教授
I’m a Doctor of Philosophy and Professor of Molecular Biology at the Mayo Clinic.
近三十五年我一直在研究麻疹病毒
I’m studying the measles virus since about 35 years.
麻疹病毒把气管当做它的蹦床
Measles uses the tracheaas a trampoline.
正是在体内的这个理想位置
It is in the ideal position
麻疹病毒得以排出和雾化分散
in the body to get expelled and aerosolized dispersing
以小颗粒状 高效地播散到空气中去
in the air in small particles very efficiently.
当麻疹病人咳嗽或打喷嚏时
When someone with measles coughs or sneezes,
飞沫中会含有麻疹病毒
these droplets contain the measles virus,
又因麻疹是呼吸系统疾病
and because measles is a respiratory disease,
人们只需吸入被污染的空气
all someone needs to do is breathe in that
就会感染上麻疹
infected air in order to contract measles.
当然 除非他们注射过麻疹病毒疫苗
Unless, of course, they’ve been vaccinated.
麻疹病毒到达肺组织时
When the measles virus reaches the lungs,
会遇到一类叫巨噬细胞的白细胞
it is met by a type of white blood cell called a macrophage.
通常巨噬细胞会寻找并消灭像病毒那样的病原体
Usually,macrophages seek out and destroydangerous pathogens like viruses.
但是麻疹病毒会欺骗巨噬细胞
But the measles virus tricks the macrophage into not
使其不被视作威胁
seeing it as a danger
巨噬细胞反而会把病毒安全运送到人体淋巴结
and instead, safely transports the virus into the body’s lymph nodes.
正是在那儿 病毒开始复制
It’s here that the virus begins to replicate
扩散到整个淋巴系统
and spread the entire lymphatic system.
我是说巨噬细胞有一个系统
Yea, I mean the macrophages thinks to have a system
可以基本清除病毒
in which they basically get rid of the virus.
但麻疹病毒能在那存活
And measles can stay there.
因此这个病毒不仅可以不被发现
So not only it is invisible
它还开始危及这些细胞
but it begins to make damage to these cells.
这些细胞的职责是
The task of these cells is
离开淋巴结 抵抗感染
also to go out and fight infection,
但是除了抵抗感染
but instead of fighting infection,
它们还带着麻疹病毒
they go out with the virus
并帮其在体内传播
and distribute it to the body.
当麻疹病毒开始传播时
Now, as the virus starts to spread,
它会进入 表达SLAM蛋白质的免疫细胞
it enters immune cells that express a protein named SLAM
它们是记忆细胞 这意味着
These cells are “ memory ” immune cells,
它们能“记住”其他那些
meaning that they remember other pathogens
曾感染过宿主的病原体
that previously infected the host.
麻疹病毒会攻击 并杀死这些免疫记忆细胞
Measles attacks and kills these SLAM-expressing memory cells
然后一旦机体对既往感染的记忆被清除后
and once those memories of past infections are erased, the body will be
机体击退下次感染的能力会更弱
in a much weaker position to fight off future infections
这就是麻疹病毒如此致命的原因
This is why measles is so deadly.
但即便它骗过了免疫系统去帮其扩散
But even though the virus has tricked your immune system to helping it,
但这并不意味着你的免疫系统屈服了
that doesn’t mean your immune system has given up.
在某个时刻 免疫系统会发现这些病毒
Well, at some point the immune system will notice
并分泌一些细胞因子 来吸引其它免疫细胞
and will secrete cytokines and attract other immune cells.
所以在某个时刻 病毒会被发现
so at some point the enemy will be identified
并被狠狠“修理”
and taken care of.
但其实对病毒来说 它们只需从宿主中出来
But for the viruses in fact it is only necessary to get out of the host
再寻找新的宿主
and find a new host.
因此 实际上最好不要杀死宿主
So it’s in fact better not to kill the host.
是的
That’s right,
不杀你能让病毒的利益最大化
It’s in the best interest of the virus not to kill you,
杀人 那是其他疾病的事
that’s some other diseases job.
麻疹病毒的工作就是寻找新的宿主
The job of the measles virus is to find a new host,
这让我们注意到了另一种病毒受体蛋白nectin4
which brings us to another protein the virus receptor: nectin4.
我们发现nectin 4 蛋白是一种上皮受体
And we discovered nectin 4 as the epithelial receptor
或者在宿主表体的麻疹病毒受体
or host exit receptor for measles virus.
当麻疹病毒播散至全身时
As measles spreads throughout the body,
它也会进入细胞表达nectin4蛋白
it also enters cells that express the protein nectin4.
这种蛋白优先在气管中表达
This protein is expressed very preferentiallyin the trachea.
麻疹病毒在气管复制得越多
And the more the virusit replicates in the trachea,
杀死的细胞也越多
the more cells it kills there.
然后死细胞逐渐堆积
This dead cell build up actually
导致宿主咳嗽或打喷嚏
causes the human host to cough or sneeze,
帮助病毒播散到下一个人类宿主
helping spread it into a new human host,
又开始新一轮的感染
bringing us right back to where we started.
那么 好消息是
Now, the good news is that
一旦你患上麻疹
once you get the measles,
机体会学习如何抵抗
your body learns how to defeat it
这样也许就不会再次患上
and you probably won’t get it again.
这和疫苗的作用原理相似
This is similar to how the vaccine works,
但不同在于注射毒性弱的剂量
but the difference is you’re given a weaker dose,
获得免疫的同时 你既不会生病
so you can become immune without getting sick
也不损伤免疫细胞
or damaging your immune cells.
疫苗使宿主对麻疹保持免疫
So the vaccine causes the host to remain immune to measles
我们认为是终身免疫 或近乎终身免疫
we think for life long or almost life long time.
而且消灭了麻疹
And without measles, other diseases,
其他致命疾病也已经减少
the ones that actually do the killing, have gone down.
基本上 因麻疹而住院的人数
Basically the number of hospitalization
已经大幅减少
has been reduced considerably sometimes to
有时大约是因一些其它传染性疾病而住院的一半
about the half for several different infectious diseases.
如果你还没打疫苗
if you haven’t been vaccinated…
是啊 疫苗很管用的
Yea,the vaccine works beautifully.
或许可以考虑一下?
Maybe think about it?
麻疹病毒或许是免疫系统的敌人
Measles may be the enemy of the immune system,
但是包括Cattaneo博士在内的研究者们
but researchers, including Dr Cattaneo,
致力于改变麻疹病毒
are working on ways to alter the measles virus,
使其能杀死癌细胞
so it kills cancer cells.
对我来说
For me,
继续研究麻疹病毒的原因是 把它变成朋友
a reason to continue study measles is to make it into a friend,
通过修改它的基因 把一个旧敌变新友
making an old enemy into a new friend by modifying it genetically.

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视频概述

该视频讲述了麻疹病毒的性质,传播途径和致病机制,以及新的发现

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收集自网络

翻译译者

玄玄

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审核员_SF

视频来源

https://www.youtube.com/watch?v=69GHdz9iRKU

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