Explainer: What is a raccoon dog and why have missing Chinese samples caused frustration among those studying the origins of the coronavirus?

Over the past three years, as international investigators have tried to solve the mystery of the origin of the coronavirus pandemic, their task has been made monumentally more difficult by the fact that vital clues have been hidden.

On Friday, the director-general of the World Health Organization, Tedros Adhanom Ghebreyesus, called out Chinese officials about samples taken three years ago at the Huanan Seafood Wholesale Market in Wuhan, asking why the data had been hidden. to the rest of the world since the beginning of the outbreak. .

He also demanded answers as to why that data, which was briefly made available to international researchers earlier this year, is now missing.

Samples taken in January 2020, in the early days of the coronavirus outbreak, support the hypothesis that the pandemic, caused by the SARS-CoV-2 virus, may have originated there, where the virus may have jumped. . to humans from raccoon dogs sold in the Huanan market.

“This data could and should have been shared three years ago,” Ghebreyesus said. “We continue to call on China to be transparent in sharing data and to carry out the necessary investigations and share the results. Understanding how the pandemic began remains both a moral and a scientific imperative.”

Here are some of the big questions surrounding data:

What is a raccoon dog?

It’s neither a raccoon nor a dog… not exactly. Native to eastern Asia, they are members of the same family as dogs, Canidae, but are more closely related to foxes. They are about the same size as a large fox, less than a meter long, with short, stubby legs that, combined with their dense fur, give them the shape of a large raccoon.

But they get their name from the black, raccoon-like markings on their faces.

Important to note about raccoon dogs: Nyctereutes procyonoidesfor zoology fans, it’s that studies have shown they are susceptible to and capable of transmitting SARS-CoV-2.

What are the data that concern us?

In late January, the data was published on the Global Initiative for Avian Influenza Data Sharing (GISAID) database, an international clearinghouse for researchers to share data on influenza and coronavirus.

These data were published together with a research paper later published by scientistsmost from the Chinese Center for Disease Control and Prevention, which was linked to samples taken at the Huanan Market in Wuhan in 2020.

Because several of the early cases of COVID-19 had connections to the Huanan market, the researchers hoped that studying samples from the market might offer some clues about the origin of the SARS-CoV-2 coronavirus and how it was initially transmitted. to the humans.

The data showed the results of analysis of 1,380 samples collected from the Huanan market in January 2020, shortly after Chinese officials closed the market on suspicion it might have been linked to the coronavirus outbreak. Of those, 73 samples tested positive for SARS-CoV-2.

What happened to the data?

Data from the January 2020 samples were published in GISAID at the end of January 2023, shortly before the Chinese research was published.

While those data were online, researchers in various countries downloaded them to do their own analyses.

Sometime shortly after that, the data disappeared from GISAID.

When the WHO contacted the Chinese investigation team regarding the disappearance, they were told that the data had been restricted to allow for updates, pending an update to the investigation paper itself.

The WHO asked the Chinese CDC researchers and the international group of scientists to present their analyzes of the data to its Scientific Advisory Group on the Origins of Novel Pathogens (SAGO), which they did on March 14.

Why is the lack of data so worrying?

There are two problems here. One is that the samples were taken by Chinese researchers in early January 2020, but that data was only recently shared with the rest of the world.

That means that for the past three years, outside of China, researchers trying to solve the puzzle of the origin of the pandemic have been doing so with one hand tied behind their back.

Mike Ryan, executive director of the WHO Health Emergencies Program, compared solving the mystery of the origin of the coronavirus to trying to solve a puzzle without seeing the actual image of the finished product on the lid of the box.

“You know that the more pieces you have in the right place, the more you start to see a picture,” he said.

“But you’re never really sure what you’re building. You’re never sure what a piece does until you put the piece in the context of all the other pieces, and then an image starts to grow and your level of confidence in what that image is grows as you put more pieces on it. correct place.”

For three years, global researchers had been trying to build this picture out of the missing puzzle pieces in what could have been the epicenter of the pandemic. And until data from samples taken at the Huanan market was uploaded in late January, they didn’t know those pieces of the puzzle existed.

The other problem is that the Chinese data, uploaded to GISAID at the end of January, was deleted soon after, making it inaccessible to scientists seeking to perform their own analyzes on samples from the Huanan market. (Some scientists around the world downloaded the data while it was still accessible.)

“The big problem now is that this data exists and it is not readily available to the international community,” WHO COVID-19 technical lead Maria Van Kerkhove said at the briefing.

“The challenge we have is that there is data that is out there, that exists, that has not been made available to us, that has not been made available to SAGO and has not been made available to the international community.”

“And until we have that information, we won’t be able to rule out different hypotheses.”

What does the data tell us?

For starters, there is no smoking gun here.

Scientists had already known since last year that there were samples from the Huanan market that tested positive for SARS-CoV-2.

What they learned from the new data was that animals were being sold at that market, and that among the 73 January 2020 samples that tested positive for SARS-CoV-2, there was DNA evidence identifying some of those animals.

Among the animals that were identified by DNA traces was the raccoon dog, an animal known to scientists to be susceptible to SARS-CoV-2.

Although it is consistent with the idea that the Huanan market was Ground Zero of the pandemic and that the virus jumped from raccoon dog to man, the evidence, as it stands, is circumstantial.

Although the samples show traces of the coronavirus and raccoon dog DNA, we don’t know if those traces were deposited at the same time. We don’t know if the raccoon dogs whose DNA traces we found were infected with the virus. And we don’t know, if they were infected, if the virus made the leap from raccoon dog to man. A raccoon dog may have been infected by another animal or by a human.

But the samples and the data from them give scientists more clues to follow. And it will probably allow them to narrow the field by eliminating some assumptions.

“We must make it clear that the virus has not been identified in an animal at the market or in samples from animals at the market, nor have we found animals that infected humans,” Van Kerkhove said.

“What this does is provide clues to help us understand what might have happened.”

Where do these clues lead scientists?

The WHO has been asking Chinese scientists to go upstream, so to speak, to start looking for the origins of those animals that were in the Wuhan market and trace them back to the farms they came from.

Doing so could give investigators clues as to how those animals got to the Huanan market, whether they were infected when they got there, or whether or not that may have happened later.

“Were these animals traded? Were they wild animals or domestic animals? Were they cultivated? Where were they grown? Van Kerkhove asked.

“We have repeatedly called for studies to be carried out in other markets in Wuhan and in Hubei and throughout China. We have repeatedly requested studies to trace those animals back to their farms of origin so that we can go back in time and see where the animals came from and if any testing has been done.”

If they can get that kind of data, if it’s shared so they can collaborate on analysis, scientists could find themselves one step closer to solving the mystery of the origin of the pandemic. And potentially closer to mitigating futures.

JOIN THE CONVERSATION

The conversations are opinions of our readers and are subject to the Code of Conduct. The Star does not endorse these views.

Leave a Comment