2020年经济学人 缺乏证据不代表没证据(1)

Few stories are as prominent in the study of infectious diseases as that of Mary Mallon,

在传染病研究领域，很少有像玛丽·梅伦的故事那样引人注目。

a cook to wealthy families, and also to a maternity¹ hospital, in New York in the early 1900s.

20世纪初，玛丽·马伦在富裕的家庭和产科医院做过厨师。

As she went from one employer to another, typhoid fever, then deadly in one case in ten, followed in her wake.

她的雇主换了一个有一个，伤寒都紧随其后，10个人中就有一个因其死亡。

Public-health officials eventually joined the dots and identified her as a carrier of Salmonella typhi, the bacterium² that causes the disease.

最终公共卫生部进行调查，并确定她是伤寒杆菌（一种会引起疾病的细菌）的携带者。

What was striking about Typhoid Mary, as the newspapers nicknamed her, was that she herself was healthy—

纸媒称她为伤寒玛丽 ，关于她的故事最引人注目的是她本身是健康的——

proof that people could harbour and transmit S. typhi without showing symptoms of the illness it causes.

这证明人们会携带和传染伤寒杆菌，且不出现任何症状。

Such silent transmission, as epidemiologists call the phenomenon, has since been observed in many diseases—among them measles³, influenza⁴ and HIV/AIDS.

流行病学家称这种现象为寂静传染，很多疾病，如麻疹、流感HIV和AIDS，都出现过这种现象。

A fresh addition to the list is SARS-COV-2, the coronavirus behind the covid-19 pandemic now raging.

最新进入这份名单的是SARS-COV-2，这是冠状病毒是目前covid-19疫情肆意的幕后推手。

Accumulating evidence suggests a substantial chunk⁵ of the infections it causes

越来越多的证据表明，它引起的感染中有很大一部分

are transmitted by people whose symptoms have not yet appeared—or even, like Mallon, who never develop symptoms at all.

是由尚未出现症状的人传播的，甚至像马伦一样，根本没有出现症状。

That has implications for the methods countries are employing to curb⁶ the pandemic.

这对各国控制全球流行病的方法有影响。

Currently, none of the evidence on asymptomatic transmission is watertight.

目前，关于无症状传染的证据没有一个是无懈可击的。

According to Gerardo Chowell of Georgia State University, in Atlanta,

根据亚特兰大佐治亚州立大学的Gerardo Chowell，

the best way to determine the share of SARS-COV-2 infections that happen in this way

要确定SARS-COV-2以这种方式传染的比列

is to follow up a large number of households in which someone is already infected and then track who subsequently infects whom.

最好的方法是对大量已有感染者的家庭进行跟踪，然后跟踪谁接着感染了谁。

For this to work, everyone involved would have to be tested daily.

这种方法需要每个人每天接受检测。

If this were done, comparing subtle variations from person to person in the virus's genetic⁷ material would show who caught it from whom.

做完这一步后，比较病毒基因材料中人与之间的细微差异，就可以发现是谁从谁那里感染了病毒。

Definitive⁸ studies of this nature are not yet available, though some are probably in the works, Dr Chowell reckons.

Chowell博士认为，目前还没有关于这一性质的权威研究，尽管一些研究可能正在进行中。

In the meantime, a growing collection of other research is shedding light on the matter. This work comes in three strands⁹.

与此同时，越来越多的其他研究正在阐明这个问题。这项工作分为三个部分。

The first is a set of studies of people in groups for which unusual circumstances have made possible tallying¹⁰ each and every infection.

首先是对人群的一组研究，不同寻常的环境使统计每一个感染患者成为可能。

These studies permit a fairly precise estimate of the share of those infected who have no symptoms.

这些研究允许对没有症状的感染者的比例进行相当精确的估计。

One such group are the passengers and crew of the Diamond Princess, a cruise ship on-board which the infection rate exploded because of a bungled¹¹ quarantine.

钻石公主号邮轮上的乘客和船员就是这样的一群人。由于疏于检疫，邮轮上的感染率出现了爆炸性增长。

Of 634 people thus infected, 52% had no symptoms at the time of testing, including 18% who never developed symptoms.

634名感染者中，52%的患者在检测时都没任何症状，其中18%从未出现症状。

The residents of Vo, an Italian town in which all 3,300 people were tested twice, is another much-cited example.

另一个被广泛引用的例子是意大利小城Vo的居民，该市所有3300人都接受了两次检测。

Of those in Vo found to be infected, 50-75% had no symptoms at the time of the test.

感染者中，50-75%的人在检测时没有出现症状。

1 maternity   

n.母性，母道，妇产科病房；adj.孕妇的，母性的

参考例句：

• Women workers are entitled to maternity leave with full pay.女工产假期间工资照发。
• Trainee nurses have to work for some weeks in maternity.受训的护士必须在产科病房工作数周。

2 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

3 measles   

n.麻疹，风疹，包虫病，痧子

参考例句：

• The doctor is quite definite about Tom having measles.医生十分肯定汤姆得了麻疹。
• The doctor told her to watch out for symptoms of measles.医生叫她注意麻疹出现的症状。

4 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。

5 chunk   

n.厚片，大块，相当大的部分（数量）

参考例句：

• They had to be careful of floating chunks of ice.他们必须当心大块浮冰。
• The company owns a chunk of farmland near Gatwick Airport.该公司拥有盖特威克机场周边的大片农田。

6 curb   

n.场外证券市场，场外交易；vt.制止，抑制

参考例句：

• I could not curb my anger.我按捺不住我的愤怒。
• You must curb your daughter when you are in church.你在教堂时必须管住你的女儿。

7 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

8 definitive   

adj.确切的，权威性的；最后的，决定性的

参考例句：

• This book is the definitive guide to world cuisine.这本书是世界美食的权威指南。
• No one has come up with a definitive answer as to why this should be so.至于为什么该这样，还没有人给出明确的答复。

9 strands   

n.（线、绳、金属线、毛发等的）股( strand的名词复数 )；缕；海洋、湖或河的)岸；（观点、计划、故事等的）部份v.使滞留，使搁浅( strand的第三人称单数 )

参考例句：

• Twist a length of rope from strands of hemp. 用几股麻搓成了一段绳子。 来自《简明英汉词典》
• She laced strands into a braid. 她把几股线编织成一根穗带。 来自《简明英汉词典》

10 tallying   

v.计算，清点( tally的现在分词 )；加标签（或标记）于；（使）符合；（使）吻合

参考例句：

• In 2007 the state set a U.S. record, tallying 141 twisters. 该州在2007年以总计出现了141个龙卷风而创下了一个美国记录。 来自互联网
• We charge extra fee at 100% of the rates of tallying fees. 我们按理货收费率的100%收取附加费。 来自互联网

11 bungled   

v.搞糟，完不成( bungle的过去式和过去分词 )；笨手笨脚地做；失败；完不成

参考例句：

• They bungled the job. 他们把活儿搞糟了。
• John bungled the job. 约翰把事情搞糟了。 来自《现代英汉综合大词典》