(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)