Short Wave - Why Pandemic Researchers Are Talking About Raccoon Dogs

Episode Date: March 23, 2023

A few weeks ago, raw data gathered in Janaury 2020 from Huanan Seafood Wholesale Market in Wuhan, China — the early epicenter of the COVID-19 pandemic — was uploaded to an online virology database. It caught the attention of researchers. A new genetic analysis from an international team provides the strongest evidence yet for natural origins of the COVID-19 pandemic and the role of one animal in particular: raccoon dogs. Short Wave co-host Emily Kwong talks with Katherine Wu, a staff writer at The Atlantic, who broke the story and explains the genetic evidence. To dive into emerging genetic evidence of this pandemic's origins, read:- Crits-Christoph et. al (2023), Genetic evidence of susceptible wildlife in SARS-CoV-2 positive samples at the Huanan Wholesale Seafood Market, Wuhan: Analysis and interpretation of data released by the Chinese Center for Disease Control- Katherine Wu's Atlantic article, The Strongest Evidence Yet That an Animal Started the Pandemic- Michaeleen Doucleff's NPR reporting, What does science say about the origin of the SARS-CoV-2 pandemic?See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Catherine Wu is a staff writer at The Atlantic. She's been reporting on the COVID-19 pandemic since March 2020, and she's written in detail about the microbiology of the virus, immunity, the vaccines. But something she's avoided weighing in on until now was the origins of the SARS-CoV-2 virus itself. I had been paying attention to this debate,

but largely purposely staying out of it. people had been volleying different ideas back and forth, but largely without hard evidence. And I kind of wanted to stay out of it until something really big broke. And that something is an analysis of raw data. Genetic samples taken from the Huanon Seafood Wholesale Market in Wuhan, China, the early epicenter of the pandemic's beginnings. And in March of this year, that data, that raw data, was quietly posted to an open genomic database by researchers affiliated with China's Center for Disease Control and Prevention.

I think that is a wild part of this story, that no one was expecting this data to randomly appear somewhere around the beginning of 2023. But it did. The data were positive for coronavirus. That wasn't new. And it had actually been shared by that same group of Chinese researchers in February 22, a whole year ago in a pre-print analysis. That's basically a scientific paper published before the peer review process. Right. That analysis from the Chinese researchers really confused people. Because what that preprint had basically said is, okay, well, there's virus here. And so immediately you start to wonder, well, who was carrying that virus?

Because the preprint concluded that, quote, no animal host of SARS-CoV-2 can be deduced. Until a few weeks ago, when the raw data that was the basis of that analysis was spotted by French scientist Florence de Bar. She and a team of international collaborators immediately downloaded the genetic sequences and began to look at it. Catherine heard about this work from confidential sources, and this week a report of their analysis was published on Zanodo, a free and open digital archive where scientists shared their work. One of the key findings in this new analysis is that there were swabs taken from this market in January of 2020. And we know that this market was shut down at the very beginning of January 2020.

So any swabs that were taken would presumably be looking at what was happening when some of the first SARS-CoV-2 or coronavirus infections were happening. So, you know, this is kind of like looking for fingerprints at the scene of a crime after the building has been shut down. Today on the show, how a new genetic analysis is providing the strongest evidence yet of the natural origins of the coronavirus pandemic. What we know, what we don't, and why everyone is talking about one animal whose DNA gave itself away. It's called The Raccoon Dog. I'm Emily Kwong, and you're listening to Shortwave, the Daily Science Podcast from NPR. Okay, Katie, before we get into the evidence, I just got to ask you, like, what threshold did this raw data analysis meet for you? That it was good enough to merit a story, your first COVID- Origin reporting you've done in almost three years.

Yeah, I think what helped me sort of crystallize the importance of this was knowing not only this new analysis was coming out, but how this new analysis sort of fit into the context of other evidence that had emerged before, right? It's basically a time capsule or as close as we're going to get. What was already known about what was happening at the market was that there was strong evidence that there were live mammals being illegally sold there. And some of those live mammals are known now to be susceptible to this virus. And so having these swabs and being able to extract out viral genetic material and animal genetic material is almost like being able to find, you know, the DNA of a prime culprit at the scene of the crime. It really just fits into this whole big picture. It's not the same as catching that same criminal red-handed. But it may be as close as we can get. What did it lead to? So when they analyze this data this time around, they did find humans again. You know, maybe there was an infected person at the market, but it seems like even likelier there was an infected animal, and one of the infected animals might have been a raccoon dog.

What evidence is there that raccoon dogs themselves harbored the virus when there were so many animals sold in the market? Yeah. So prior to this, there were two papers published last year in the journal Science, looking at the Huanon market as a possible epicenter for the pandemic. And they basically accumulated a bunch of epidemiological evidence figuring out that there were probably live animals being sold there, raccoon dogs among them, which I should say now are these little fox-like creatures that have these sort of classic bandit-like faces that remind people of, you know, raccoons. You know, they had photos that raccoon dogs were in cages at the market in 2014, as well as at the end of 2019, right when the outbreak was probably starting. And laboratory experiments have shown that raccoon dogs can catch the coronavirus and also spread it.

So they're a totally reasonable culprit. And we know that, you know, from China's history of wet markets, they do appear at wet markets. And they are also bred in the country for fur farming. And at one stall in particular, stall 29, which is actually where scientists have accumulated photo evidence that there were raccoon dogs being sold at this market. There's raccoon dog DNA right next to the virus. And again, this is not a slam dunk. This is not like we have a live virus sample taken from a raccoon dog. Right.

And this is a really important point to highlight, which is just that the swabs were not taken from raccoon dogs. You write, quote, to researchers' knowledge, raccoon dogs were not tested at the market and had likely been removed prior to the authorities coming in. The photos you mentioned that were circulating on Weibo, the really popular China-based chat app, certainly suggests there were raccoon dogs being sold there. But this also doesn't mean, just to go back to how viruses jumped from animals to people, that raccoon dogs were the intermediate host, right? The creature that passed the coronavirus onto us. Yeah.

So I think that is what is really tricky here. Without having samples taken directly from live animals, you know, that show the virus was there, this story may never be a totally open and shut case. Like exactly as you point out, you know, even if researchers are eventually to prove with additional evidence say that hasn't yet come to light that there definitely were infected raccoon dogs at the market, that doesn't guarantee that they were the animals that passed to a bunch of people who then started circulating the virus among other human communities, which is, you know, how the pandemic would have started if the Juanon market was a catalyst.

Importantly, if you compare this to the other idea that people have about how this pandemic where it started, a laboratory accident where researchers were experimenting with this virus in a lab and someone got infected and carried it elsewhere, there's not that kind of genetic evidence suggesting, you know, oh, a person infected in the lab and then they brought it to family members or friends elsewhere. That sort of super hard evidence has not yet been found. But more and more, it really is looking like the market had infected animals. It's like the data is continuing to circle closer and closer in tighter and tighter concentric circles around the idea of the market really being a catalyst and infected wild animals being at the center of it.

Yeah. Okay. Bork, pork. A caveat rich answer. Just to contextualize this a little bit, to take a step back from our current pandemic moment, listening to you, it's making me think about a conversation I had in 2020 with Dr. Linfa Wong, who's one of the scientists that helped determine where the 2002 to 2004 SARS outbreak came from. And he was part of a team that traced it to horseshoe bats in a cave in the Yunnan province of China.

That's the closest evidence we have of that and how it jumped to humans through animals sold at wet markets. But the point I really want to discuss with you is just he said, you know, it was a, a detective hunt that took a decade. They were sampling animals, horseshoe bats across the country, and it took a really, really, really long time. And I think that this work takes a very long time is something that is hard for people to square with a pandemic that has been so immediately devastating. Yeah, that's a really great point. What are some of the reasons why, like, what's the holdup when it comes to this pandemic. It's a great question and I can't fully answer in part because I can't speak for how the Chinese government is looking at this at this point in time. There has been a lot of resistance, you know,

based on what I've learned in my reporting about the Chinese government not really wanting the narrative put forth that the pandemic did start within their borders. They've, of course, pushed back hard against the lab leak narrative, but also against the wet market narrative. And, you know, the experts that I've spoken to. They also can't know for sure, but there's speculation that, you know, it maybe doesn't look great if we've had two wet market-borne coronaviruses spilling out into the human population. It also does not potentially speak very well of how China has handled its relationship with wildlife. If it was indeed raccoon dogs at Huanon or other animals there, many of them may have likely been illegally sold, illegally traded, and that is a whole other.

sort of biosecurity issues that is not just about coronaviruses, not just about this pandemic, but the sort of practices that could lead to other spillovers in the future, regardless of how this particular pandemic started. Mm-hmm. Mm-hmm. Did the scientists you've spoken to who've pursued this, whether outside of China or within China, have they shared with you that the struggle, just the fact that they're up against political and biosecurity forces that prevent science from really carrying on as it could?

Yeah, that's a great question. I think right now, all the researchers that I've spoken to have really been trying to make this a collaborative effort. Obviously, this is a global problem, and ideally that will be addressed with global collaborative efforts, but it is tricky. I think another central part of this story is data availability. It took years for that raw data containing those on market genetic sequences to become publicly available, it's still not entirely clear what was behind the lag. And the data has actually since disappeared. The researchers who are doing this new analysis,

they did download the data and analyze it and, you know, they have it backed up. But it is not their data that they collected, and they fully acknowledge that. It, you know, it will be up to the researchers who have collected this data to continue sharing it to ensure that the world has access to it. because figuring out how this pandemic started will ideally help us prevent the next one. Yeah.

In a few places in the article, you write about the realities that there are many individuals around the world who will continue to refuse that this virus had natural origins. And I'm wondering how it felt to write the piece knowing that, that some people reading it would still just disagree. Yeah, it's a great question. And I think this is a common thing that comes up in science support. including with much less politically charged topics, but science is always evolving. We are often adding data to very murky pictures, and I was really encouraged to see this data enough to write about it and feel like it was strong enough that I wanted to sort of dive into this very

charged debate, but I also knew that it was not going to be a total slam dunk, and that's okay. I hope that people will just continue to accept new evidence as it comes in, and even if it's not enough to fully convince them, maybe it makes them rethink a little bit. And hopefully we eventually come to a place where there is at least consensus in the scientific community. And we'll just try and keep communicating about it. Catherine Wu, staff writer at the Atlantic, thank you so, so much for talking to me. And I hope to have you back someday to talk about this or about other things on Troy. Always delighted to be here. Thanks for having me. Check out the episode notes to read Katie's article.

and the report itself, which was published on Monday evening after our taping. I'd also encourage you to follow the work of our colleague NPR correspondent, Mike Lean Duke-Cleff, for more on the origins of zoonotic disease. Today's episode was produced by Thomas Liu. It was edited by managing producer Rebecca Ramirez and fact-checked by Anil Oza. Special thanks to Warren Great Singer and Ted Hancock for technical support. Brendan Crump is our podcast coordinator, our senior director of programming is Beth Donovan,

and the senior vice president of programming is Anya Grundman. I'm Emily Kwong. Thank you so much for listening to Shortwave. The Daily Science Podcast from NPR.