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  • (bright upbeat music)

  • - [Narrator] A seafood market,

  • a virology lab, and a mine deep in the mountains.

  • Key events at these places in China could be crucial

  • to understanding how a small cluster of coronavirus cases

  • ended up sweeping the world.

  • Because almost a year and a half

  • into this global health crisis, politicians and scientists

  • are still debating how it all started.

  • - [Betsy] If you're gonna look for the origin of a pandemic,

  • you really should start right away when the clues are fresh.

  • Right now that's looking pretty difficult.

  • - [Narrator] That's because access to Wuhan

  • has been really limited.

  • - Until you nail it down definitively,

  • you've always got to keep an open mind

  • that it might be something else.

  • - [Narrator] The main hypothesis

  • is that the virus originated from bats.

  • Jumped to another animal, then to us.

  • And the leap to humans

  • might've happened here at this market.

  • 10 miles away is where some scientists believe

  • that the virus may have accidentally leaked from a lab.

  • And both of these spots in Wuhan

  • have an increasingly important connection to one place

  • that's over 1000 miles away

  • in the mountains of Yunnan province.

  • So we visit these key places

  • to break down what we know about the coronavirus

  • to understand how the global pandemic may have started.

  • Stop number one, the Huanan Seafood Market,

  • December 31st, 2019.

  • This is the day the WHO learned

  • about a cluster of pneumonia cases in Wuhan.

  • And increasingly, the focus was on the market.

  • The complex spans an area that's the size

  • of nine football fields and has over 600 stalls.

  • About 10 of those were selling wild animals

  • like bamboo rats, hedgehogs and hog badgers.

  • - [Betsy] These wildlife are raised on farms,

  • sometimes in crowded conditions

  • where it's easy for animals to spread viruses back

  • and forth between each other

  • and the viruses start to mix and match and can change.

  • - [Narrator] Some wildlife

  • that are receptive to coronavirus infections

  • are consumed in China,

  • either for food or used in traditional medicine.

  • - [Betsy] These animals are shipped to urban markets

  • where they are sold sometimes live and butchered onsite.

  • And all this contact with live possibly infected animals

  • or the infected fresh meat

  • has become a major concern in recent years.

  • - [Narrator] And in Wuhan, many of the first cases

  • were either vendors who worked at the market,

  • or people who had shopped there.

  • By January 1st, Chinese authorities shut the place down.

  • - [Betsy] Well, originally Chinese authorities did feel

  • that it possibly came from the Huanan Market

  • and from wild meat of some sort.

  • - [Narrator] About three weeks later,

  • scientists in Wuhan and Beijing published

  • a pivotal paper in the medical journal, The Lancet.

  • This chart shows how some of the early cases

  • were people who hadn't been at the market.

  • More than a year later, there was new data

  • to piece together a clearer picture,

  • that's because China allowed

  • a group of international scientists to come to Wuhan

  • for several weeks to visit the market and hospitals.

  • - [Betsy] A team from the WHO that visited China

  • also learned going through the data

  • that by mid to late December,

  • the viruses that were infecting people

  • were genetically different enough

  • that they knew it wasn't all coming from the same place.

  • - [Narrator] The WHO said the presence

  • of early cases not linked to the market could suggest

  • that it was not the original source of the outbreak.

  • And increasingly, one place a team visited

  • is at the center of another hypothesis,

  • the Wuhan Institute of Virology.

  • - This is a world-class Institute

  • with high security laboratories

  • and does a lot of work with scientists outside of China,

  • very vibrant collaboration before the pandemic.

  • They would travel to caves where bats are known to roost

  • and take samples, and then study them in their lab.

  • - [Narrator] These bat coronaviruses and pathogens

  • are cataloged in databases.

  • The researchers used this library of information

  • to compare it to blood samples

  • and oral swabs from patients in Wuhan.

  • And about a month after the market was closed,

  • these researchers discovered that COVID-19

  • had a 96.2% genetic match with the bat coronavirus

  • that the institute had found back in 2013.

  • Scientists around the world consider this

  • a breakthrough in the search for COVID-19 source,

  • because it strongly indicated

  • that it could have originated in bats.

  • - This laboratory studies bat coronaviruses right in Wuhan,

  • was an obvious question, could it have escaped?

  • And even the Institute's own researchers asked that question

  • and went and did their own research.

  • - [Narrator] As questions swirled

  • around a possible accident at the institute,

  • it's top bat coronavirus expert said

  • the virus didn't leak from her labs,

  • and none of its staff have tested positive for COVID-19.

  • - These are not the first times

  • that we've had a world exposed to virus

  • as a result of failures in a Chinese lab.

  • - Last year, what started out as a basic scientific question

  • got politicized with a lot of finger pointing at China

  • yet there was no evidence presented.

  • (journalists chattering)

  • - [Man] Anything sir.

  • - [Narrator] And there was also limited access to data

  • during the WHO-led team's trip to Wuhan.

  • One of the stops was the virology institute.

  • - They asked questions and they had a tour,

  • but they didn't get any firsthand look

  • at databases, medical records, any sort of raw data

  • which would have shed light

  • on whether the virus could have escaped or not.

  • - [Narrator] Almost a week later,

  • scientists summed up their findings at a press conference.

  • They said the spillover from an intermediate host to humans

  • was likely to very likely,

  • and as for questions surrounding the lab.

  • - The findings suggest

  • that the laboratory incident hypothesis

  • is extremely unlikely.

  • - [Narrator] But later, the WHO chief said

  • the team didn't sufficiently examine the lab hypothesis,

  • and called for a fuller probe.

  • Three months later after that press conference,

  • a group of leading virologists and epidemiologists

  • wrote a letter saying there were no findings

  • in clear support of either

  • a natural spillover or a lab accident.

  • - This group of people is not saying

  • that they believe it came from a lab.

  • What they're saying

  • is that there's not enough evidence to rule it out.

  • Scientists investigate hypotheses

  • and they rule them out one by one.

  • And they just said that process hasn't been able to happen

  • and it needs to happen.

  • (speaking in foreign language)

  • - [Narrator] China says it's cooperated fully

  • with the effort to search for COVID-19's source

  • and has urged the WHO

  • to investigate early cases in other countries.

  • (bright music)

  • And one place that could provide some new evidence

  • for both hypotheses, Yunnan.

  • It's China's Southwestern most province

  • and home to many coronavirus-carrying bats.

  • And could set the stage for where the investigation

  • into the origin of the virus could go next.

  • - It's clearly an area where coronaviruses are circulating,

  • including coronaviruses that are very closely related

  • to SARS, the epidemic in 2003.

  • - [Narrator] Researchers

  • from the Wuhan Institute of Virology went to Yunnan

  • to study large bat populations inside caves.

  • In these crowded spaces, viral strains can mix together,

  • and become the building blocks of coronavirus

  • that then jump to humans.

  • - [Betsy] And at the same time,

  • there are wildlife farms there

  • that supply animals to Wuhan.

  • - [Narrator] Scientists say, this could explain how a virus

  • from a bat cave leapt to an intermediate host

  • then made its way to the market.

  • There was also a mine in Yunnan where scientists

  • from the institute spent some time from 2012 onwards.

  • It's where six miners who'd been clearing bat droppings

  • had gotten sick, and developed an unexplained pneumonia.

  • Three of them died.

  • So in 2013, scientists from the Institute went to the cave

  • to collect samples from bats.

  • A virus from one of these samples turned out

  • to be that 96.2% genetic match

  • that was discovered by the institute, inhaled as a big break

  • during the early days of the pandemic.

  • It took months for the institute

  • to reveal that the bat coronavirus samples

  • were from the mine, and that there were sick miners.

  • - The failure to describe it more

  • became kind of a touchpoint

  • for people who wanted more information

  • from the laboratory about the viruses they do have,

  • and what work they've been doing with them.

  • - [Narrator] Then, there was another allegation

  • about the institute that surfaced more than a year later.

  • - What US intelligence officials learned

  • is that there were three researchers

  • who became ill enough to seek hospital care.

  • They had symptoms that were like COVID,

  • but the symptoms like COVID are also like flu symptoms.

  • And flu was definitely circulating in Wuhan at that time.

  • - [Narrator] Four days after the intelligence report

  • about the sick lab workers, the Biden administration ordered

  • a US intelligence inquiry into the two scenarios.

  • China said the report was untrue.

  • (speaking in foreign language)

  • - Some people don't believe China

  • and say this has to be a coverup.

  • Others say we just need to verify,

  • though that's what we do in science.

  • We verify, we look at the data and reach our own conclusion.

  • It really does boil down to a question of transparency.

  • - [Narrator] So for any progress to be made

  • in the origins of the virus,

  • it'll ultimately require more data,

  • and fuller access to where it was first detected in China.

  • (bright music)

(bright upbeat music)

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武汉实验室假说还是人兽飞跃?(Wuhan Lab Hypothesis or Animal-Human Leap? The Hunt for Covid-19’s Origins | WSJ)

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    joey joey 發佈於 2021 年 07 月 24 日
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