经济学人下载:Covid-19的多副面孔(2)

Patients brought into hospital with all the symptoms of a heart attack have later been found to be suffering from cardiac inflammation caused by the virus.
因心脏病发作症状而入院的病人之后被发现患有由该病毒引起的心脏炎症。

It has also demonstrated that it can begin as a kidney infection, or even as meningitis,
这也表明，它可以以肾脏感染开始，甚至是脑膜炎，

before sometimes going on to cause its characteristic respiratory problems.
之后才可能会引起其特有的呼吸问题。

Precisely why SARS-COV-2 manifests itself in so many ways while all of the various strands of influenza present the same symptoms is not clear.
确切地说，尚不清楚为什么SARS-COV-2有这么多表现方式，而所有不同的流感都表现出相同的症状。

But there are several theories. One proposed by Stanley Perlman, an immunologist at the University of Iowa,
但有几种解释。一种是由爱荷华大学的免疫学者Stanley Perlman提出的，

is that in actual fact, nothing odd is really going on. The novel virus's many faces are being noticed merely because it is a new disease and dangerous,
这种理论认为，其实并没有发生什么奇怪的事情。人们之所以注意到这种新型病毒的多面性，仅仅是因为它是一种危险的新疾病，

and so is being studied intensely. He postulates that if influenza were looked at with equal intensity,
所以大家都对它进行深入研究。他假设，如果对流感进行同等强度的观察，

it might also be shown to manifest in other ways—as a mild winter stomach infection, for example.
它可能也会表现出多面性——例如，一种轻微的冬季胃部感染。

An idea suggested by William James, a virologist at the University of Oxford, is that the two-phase activity of SARS-COV-2,
另一种想法是由牛津大学的病毒学家William James提出的，他认为SARS-COV-2的两期活动

whereby it starts in the upper respiratory tract and then migrates deep into the lungs, is the critical factor that allows it to travel around the body.
——从上呼吸道开始，然后迁移至肺部——是它在体内传播的关键因素。

"Influenza rarely gets deep into the lungs," he says. "This new virus gets down there all the time."
“流感很少会渗入肺部，”他说。“这种新型病毒一直在那里传播。”

Since the lungs are designed to move gases in and out of the bloodstream
因为肺的功能是将气体从血液中移进移出

(their highly vascularised airs sacs have a collective surface area of about 50 square metres), viruses find it easy to make a similar journey.
（它们的高度血管化的空气囊的总表面积约为50平方米），病毒很容易进行类似的旅行。

Dr Perlman agrees that this notion may be correct, but points out that the only way to be sure is to take samples from places other than the respiratory tract,
Perlman博士认为这种想法可能是对的，但他指出要确认这一点的唯一方法是从早期阶段感染患者的呼吸道以外的地方采集样本，

in people suffering from early stages of the infection, to see if virus migration depends on getting to the lungs first.
以观察病毒的迁移是否依赖于先到达肺部。

As for why the disease sometimes makes its initial appearance in the digestive system, as it did in Dr DeBenedet's patient, this is probably because ACE2,
至于为什么这种疾病有时会在消化系统中首次出现，就像Dr DeBenedet医生的病人那样，这可能是因为ACE2，

the cell-surface protein that SARS-COV-2 binds to, is abundant in the gut as well as the lungs.
这种与SARS-COV-2结合的细胞表面蛋白，在肠道和肺部的含量都很丰富。

How the virus gets through the highly acidic stomach unharmed is unknown. But clearly it can, and does.
尚不清楚病毒是如何毫发无伤地通过高酸性胃部的。但显然它可以，而且确实如此。

ACE2 is also found in the kidneys and the heart, which may help explain why symptoms manifest there, as well.
肾脏和心脏中也有ACE2，这或许可以帮助解释为什么症状会在那里出现。

By contrast, the entry molecules preferred by influenza viruses are almost exclusive to the upper respiratory tract.
相比之下，流感病毒首选的进入分子几乎只存在于上呼吸道。

Knowing all this may make identification of the early stages of COVID-19 easier, and thus help to ease the plight of future cases like that of Dr DeBenedet's patient.
了解这一切或许能使COVID-19-19早期阶段的识别更容易，从而有助于缓解未来病例的困境，如DeBenedet医生的病人那样的困境。