新的冠状病毒是否悄无声息地传播?

新的冠状病毒是否悄无声息地传播?

Public health officials attempting to contain the new coronavirus are trying to figure out how easily it spreads. One key question is whether people who are infected but show no symptoms can infect other people.

试图控制这种新型冠状病毒的公共卫生官员正在试图找出它传播的容易程度。一个关键问题是，被感染但没有表现出症状的人是否会传染给其他人。

"If you have a lot of people who [have mild disease or are] asymptomatic and not seeking medical care for respiratory illness but are still contagious, you're going to have a very difficult time," says Jeffrey Shaman, a professor of environmental health sciences at Columbia University.

哥伦比亚大学的环境健康科学教授杰弗里•沙曼表示:“如果有很多人(患有轻度疾病或无症状)，没有寻求治疗呼吸系统疾病的医疗服务，但仍然具有传染性，那么你将面临非常艰难的时期。”

Two previous deadly outbreaks of coronavirus – SARS and MERS – only spread from people who were showing symptoms of disease.

以前两次致命的冠状病毒爆发——非典和中东呼吸综合征——只从有疾病症状的人身上传播。

But Shaman has looked at more common coronaviruses, in particular four other coronaviruses that usually don't cause anything more serious than a cold. He's found many people shed those viruses even when they report no symptoms at all. (His results are not peer-reviewed but are available as a preprint).

但沙曼研究了更常见的冠状病毒，特别是其他四种冠状病毒，它们通常不会引起比感冒更严重的症状。他发现许多人即使在完全没有症状的情况下也会感染这些病毒。(他的研究结果没有经过同行评审，但可以作为预印本获得)。

His study found the coronavirus in the nasal passages of people who didn't report any symptoms, "and it's going to leak out as they're speaking and breathing and coughing and sneezing and wiping their nose," Shaman says.

他的研究发现，冠状病毒存在于那些没有报告任何症状的人的鼻腔通道中，“当他们说话、呼吸、咳嗽、打喷嚏和擦鼻涕时，病毒就会泄露出来，”沙曼说。

"Whether it's ... a sufficient quantity to make somebody else infectious, we can't discern that from what we've done."

“它是否…足以让其他人传染，我们无法从我们的所作所为中看出这一点。”

Likewise, it's hard to know what's up with the novel coronavirus. Scientists in Germany reported a case in the New England Journal of Medicine on Jan. 30 in which a visitor from China without symptoms passed the disease along to a colleague in Munich. But, as Science magazine first reported, that was wrong.

同样，我们也很难知道新型冠状病毒是怎么回事。1月30日，德国科学家在《新英格兰医学杂志》上报道了一起病例，一名没有症状的中国游客将病毒传染给了慕尼黑的一位同事。但是，正如《科学》杂志最初报道的那样，这是错误的。

The woman actually did have symptoms.

这个女人确实有症状。

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, had cited that case last week at a White House meeting in which health officials announced a quarantine for people returning from the disease's hotspot in China. He says the errant letter in the journal doesn't alter his view.

美国国家过敏与传染病研究所所长安东尼·福奇博士上周在白宫的一次会议上提到了这一病例。卫生官员在会上宣布，将对从中国这一疾病高发地区回来的人进行隔离。他说，杂志上那封错误的信并没有改变他的观点。

Fauci says he's been talking to trusted colleagues in China about this issue, and "they told me without a doubt there is some degree of asymptomatic transmission."

福奇说，他一直在与他信任的中国同事讨论这个问题，“他们毫无疑问地告诉我，存在某种程度的无症状传播。”

But he says to the extent it's happening, it doesn't explain the apparently explosive spread of this disease within China.

但他说，就目前的情况来看，这并不能解释这种疾病在中国的爆炸性传播。

The history of respiratory disease is that "asymptomatic transmission is not the main driver of [any] outbreak."

呼吸道疾病的历史表明，“无症状传播并不是(任何)疫情爆发的主要原因。”

Even so, Maria van Kerkhove at the World Health Organization says this question is subject of intense scrutiny right now.

即便如此，世界卫生组织的玛丽亚·范·科霍夫表示，这个问题目前正受到密切关注。