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这个国家用狗“嗅探”新冠病毒,比核酸检测还准

这个国家用狗“嗅探”新冠病毒,比核酸检测还准

David Meyer 2020年09月25日
狗的嗅觉更加可靠,而且能更快得出结果。

以后抵达芬兰赫尔辛基机场的旅客,将很快得到非常可靠的新冠病毒检测,执行检测的是嗅探犬。

这是到目前为止规模最大的一次利用狗嗅出新冠病毒的试验;一个月前迪拜国际机场启动了类似项目。另外,德国发布的研究显示,狗检测新冠病毒的准确率接近94%。

9月23日开始的芬兰试验使用了四只嗅探犬,每次两只,因为它们很容易疲劳。但执行该试验的赫尔辛基大学(University of Helsinki)研究人员表示,他们有10只经过训练的嗅探犬,可以在机场充满不同气味的嘈杂环境中工作。

研究人员鼓励旅客使用消毒纸巾提取皮肤汗液拭子(迪拜的试验需要将塑料软管放到旅客的腋下),并将样本放到一个广口瓶中。广口瓶会通过墙上的洞递给在一边等待的嗅探犬。检测只需要几秒钟即可完成。之后,受试者需要接受新冠病毒标准聚合酶链反应(PCR)检测,用于收集比较数据进行研究。

首席研究员安娜•耶尔姆-比约克曼告诉《财富》杂志,如果嗅探犬的检测结果呈阳性,“我们会带领乘客,保证他们接受PCR检测。”芬兰建议感染新冠病毒的旅客入境后进行自我隔离,但并没有强制隔离制度。

“高度敏感”

试验在9月23日开始,到欧洲时间下午早些时候,已经进行了约50次检测。耶尔姆-比约克曼表示,研究团队预期每天进行约100次检测,每500次测试会有1例阳性病例。

她说:“狗能够检出PCR检出的所有阳性病例,还可以比PCR多检测出5%左右的阳性病例。狗非常敏感。它能够发现更多曾经感染过新冠肺炎且体内仍然残留病毒的阳性病例,尽管他们已经不再具有传染性。而且,狗可以在患者出现临床症状前提前一周将其检测出来。”

狗竟然敏感到能够检测出已经度过传染期的人体内的病毒,这是否有些夸张?

耶尔姆-比约克曼认为这没有任何问题。她说:“有些PCR检测也可以做到这一点……我们之所以没有改变截止点,是因为目前没有有关人类传染周期长度的研究。在有足够多的科学证据支持某个截止点之前,我们会让狗来告诉我们[已经检测出非常少量的病毒]。然后我们会再教它们:‘如果低于这个水平,就不需要告诉我们。’”

耶尔姆-比约克曼的团队从4月开始一直在进行初步试验,在5月宣布试验取得成功。但她们的研究结果还没有发表任何经过同行审议的论文,甚至没有提交文章接受同行审议。她表示,当前情况紧急,因此她的团队直接开始试点。

她说:“我们知道用狗进行检测能够成功。我们在五年前就开始进行这项研究,训练它们[检测]癌症等疾病。我们认为在此次疫情期间,对于芬兰最重要的是可以提供良好的检测。狗的检测准确率高于PCR检测。虽然我们完全颠倒了科研的步骤,但在新冠疫情期间,我们知道完成同行审议需要三个月时间,因此我们还没有发表经过同行审议的论文,就首先进行了实际操作。”

增加信心

理论上,赫尔辛基机场使用的技术能够快速正式推广。然而,耶尔姆-比约克曼表示,要允许狗近距离嗅探旅客,而不是在另外一个房间嗅探样本,需要芬兰修订立法。比如在音乐厅入口这种环境中,狗可以像传统嗅探犬一样工作。

受到新冠疫情的冲击,航空业非常渴望让人们重新选择乘飞机出行。病毒检测对保证旅客和边防部门的信心都至关重要,而且考虑到大型机场的乘客吞吐量,速度是关键。

同样在9月23日,路透社报道称,汉莎航空(Lufthansa)正在与药企罗氏(Roche)谈判部署抗原检测。抗原检测比PCR检测的速度更快,成本更低,只要15分钟左右就能够得出结果(PCR检测需要几个小时)。

意大利航空(Alitalia)甚至开通了罗马与米兰之间的航班,专门服务抗原检测呈阴性证明体内没有病毒的旅客。

但抗原检测的假阴性比例高于PCR检测。似乎依靠狗的嗅觉更加可靠,而且可以更快得出结果。这种测试能够自动完成。一家法国医院准备大量部署非常昂贵的呼吸式酒精测试仪用于病毒检测,几秒钟之内就可以得出结果。这种设备最初被设计用于大气科学。但嗅探犬的体型更小、成本更低,而且已经能够广泛部署。(财富中文网)

翻译:刘进龙

审校:汪皓

以后抵达芬兰赫尔辛基机场的旅客,将很快得到非常可靠的新冠病毒检测,执行检测的是嗅探犬。

这是到目前为止规模最大的一次利用狗嗅出新冠病毒的试验;一个月前迪拜国际机场启动了类似项目。另外,德国发布的研究显示,狗检测新冠病毒的准确率接近94%。

9月23日开始的芬兰试验使用了四只嗅探犬,每次两只,因为它们很容易疲劳。但执行该试验的赫尔辛基大学(University of Helsinki)研究人员表示,他们有10只经过训练的嗅探犬,可以在机场充满不同气味的嘈杂环境中工作。

研究人员鼓励旅客使用消毒纸巾提取皮肤汗液拭子(迪拜的试验需要将塑料软管放到旅客的腋下),并将样本放到一个广口瓶中。广口瓶会通过墙上的洞递给在一边等待的嗅探犬。检测只需要几秒钟即可完成。之后,受试者需要接受新冠病毒标准聚合酶链反应(PCR)检测,用于收集比较数据进行研究。

首席研究员安娜•耶尔姆-比约克曼告诉《财富》杂志,如果嗅探犬的检测结果呈阳性,“我们会带领乘客,保证他们接受PCR检测。”芬兰建议感染新冠病毒的旅客入境后进行自我隔离,但并没有强制隔离制度。

“高度敏感”

试验在9月23日开始,到欧洲时间下午早些时候,已经进行了约50次检测。耶尔姆-比约克曼表示,研究团队预期每天进行约100次检测,每500次测试会有1例阳性病例。

她说:“狗能够检出PCR检出的所有阳性病例,还可以比PCR多检测出5%左右的阳性病例。狗非常敏感。它能够发现更多曾经感染过新冠肺炎且体内仍然残留病毒的阳性病例,尽管他们已经不再具有传染性。而且,狗可以在患者出现临床症状前提前一周将其检测出来。”

狗竟然敏感到能够检测出已经度过传染期的人体内的病毒,这是否有些夸张?

耶尔姆-比约克曼认为这没有任何问题。她说:“有些PCR检测也可以做到这一点……我们之所以没有改变截止点,是因为目前没有有关人类传染周期长度的研究。在有足够多的科学证据支持某个截止点之前,我们会让狗来告诉我们[已经检测出非常少量的病毒]。然后我们会再教它们:‘如果低于这个水平,就不需要告诉我们。’”

耶尔姆-比约克曼的团队从4月开始一直在进行初步试验,在5月宣布试验取得成功。但她们的研究结果还没有发表任何经过同行审议的论文,甚至没有提交文章接受同行审议。她表示,当前情况紧急,因此她的团队直接开始试点。

她说:“我们知道用狗进行检测能够成功。我们在五年前就开始进行这项研究,训练它们[检测]癌症等疾病。我们认为在此次疫情期间,对于芬兰最重要的是可以提供良好的检测。狗的检测准确率高于PCR检测。虽然我们完全颠倒了科研的步骤,但在新冠疫情期间,我们知道完成同行审议需要三个月时间,因此我们还没有发表经过同行审议的论文,就首先进行了实际操作。”

增加信心

理论上,赫尔辛基机场使用的技术能够快速正式推广。然而,耶尔姆-比约克曼表示,要允许狗近距离嗅探旅客,而不是在另外一个房间嗅探样本,需要芬兰修订立法。比如在音乐厅入口这种环境中,狗可以像传统嗅探犬一样工作。

受到新冠疫情的冲击,航空业非常渴望让人们重新选择乘飞机出行。病毒检测对保证旅客和边防部门的信心都至关重要,而且考虑到大型机场的乘客吞吐量,速度是关键。

同样在9月23日,路透社报道称,汉莎航空(Lufthansa)正在与药企罗氏(Roche)谈判部署抗原检测。抗原检测比PCR检测的速度更快,成本更低,只要15分钟左右就能够得出结果(PCR检测需要几个小时)。

意大利航空(Alitalia)甚至开通了罗马与米兰之间的航班,专门服务抗原检测呈阴性证明体内没有病毒的旅客。

但抗原检测的假阴性比例高于PCR检测。似乎依靠狗的嗅觉更加可靠,而且可以更快得出结果。这种测试能够自动完成。一家法国医院准备大量部署非常昂贵的呼吸式酒精测试仪用于病毒检测,几秒钟之内就可以得出结果。这种设备最初被设计用于大气科学。但嗅探犬的体型更小、成本更低,而且已经能够广泛部署。(财富中文网)

翻译:刘进龙

审校:汪皓

For the rest of this year, passengers arriving at Finland’s Helsinki Airport will be able to get quick, apparently very reliable coronavirus tests from…dogs.

It’s one of the biggest trials so far in the use of dogs to sniff out SARS-CoV-2; a similar test has been underway for a month at Dubai International, and already published research from Germany indicates dogs have a detection rate of around 94% for the virus.

In the Finnish trial, which began September 23, four canines are being used—two at a time; they tire easily—though the University of Helsinki researchers behind the scheme say they have 10 that have been trained and can be relied upon to work in a noisy airport environment that is full of different smells.

Passengers are invited to take simple sweat swabs from their own skin using sterile tissue (the Dubai trial involves sticking plastic tubes into people’s armpits), then drop the tissue into a jar that is passed through a hole in the wall to the waiting dog. The test takes a few seconds. The subjects are then asked to take a standard polymerase chain reaction (PCR) test for the coronavirus, so comparative data can be gathered for the study.

If the canine test comes back positive, “we take them by the hand and see 100% that they go to the PCR test as well,” lead researcher Anna Hielm-Björkman told Fortune. People arriving in Finland with the coronavirus are encouraged to self-isolate, though the country has no heavily enforced quarantining system for such cases.

“So much more sensitive”

The trial began September 23, and early in the European afternoon around 50 tests had already been conducted. Hielm-Björkman said the team expected to conduct around 100 tests a day and to see around one positive case in every 500 tests.

“It finds all the positives that the PCR finds and then [around] 5% more positives than the PCR. The dog is so much more sensitive,” she said. “It finds more positives where people have had the disease and still have the virus in their body, even though they’re not contagious anymore. Also what it’s able to [do] is it can find the positive ones up to one week before they get their clinical symptoms.”

If the dogs are so sensitive that they can detect the virus in people who have passed through the contagious stage, is that not overdoing it?

Not a problem, said Hielm-Björkman: “Some PCR tests do the same thing…The reason we haven’t changed the cutoff point yet is there is really no research yet on how long people are contagious. We will let the dogs tell us [that very small amounts of the virus have been detected] until there is enough science to back up a cutoff point. Then we’ll teach them again: ‘If it’s lower than this, you don't need to tell us.’”

Hielm-Björkman's team has been conducting preliminary tests since April, and first announced success in May. Although it has not yet produced any peer-reviewed paper about its findings—or indeed submitted an article for peer review—she said the urgency of the situation had led the team to move straight to this pilot.

“We know the dogs work,” she said. “We’ve been doing this research for five years before, training them [to detect] cancer and other diseases. We thought in this time of an epidemic, the most important thing for Finland at the moment is getting these good tests. Dogs are superior to PCR tests. It’s totally backwards, but in a time of COVID, knowing it takes three months to get something peer reviewed, we went operational before we had a peer-reviewed article.”

Instilling confidence

In theory, the technique being used at Helsinki Airport could be formally rolled out quite quickly. However, a scenario involving dogs sniffing passengers up close, rather than sniffing their samples in another room, would require a legislative change in Finland—this would be relevant in settings such as the entrance to a concert hall, where the dogs would operate like traditional sniffer dogs, Hielm-Björkman said.

The aviation sector, which has been hammered by the COVID-19 pandemic, is desperate to get people back on flights. Testing is crucial both for passenger confidence and for the confidence of border authorities, and—given the volume of passengers passing through large airports—speed is of the essence.

Also on September 23, Reuters reported that Lufthansa is talking to drugmaker Roche about the deployment of antigen tests—a faster and cheaper alternative to PCR tests—that produce results in 15 minutes or so (PCR tests take hours).

Alitalia is even running special flights between Rome and Milan that are reserved for passengers that have had negative antigen tests, indicating that they do not have the virus in their systems.

But antigen tests are known to produce more false negatives than PCR tests. It appears the smell-based technique is more reliable, and even quicker in producing results. It’s a test that can be automated—a French hospital is preparing to deploy an enormous and very expensive Breathalyzer, originally designed for atmospheric science, to get results within seconds—but sniffer dogs are smaller, cheaper, and already widely available.

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