By William J. Furney
In a dramatic twist in the hunt for COVID-19’s origins, scientists have uncovered fresh evidence that raccoon dogs may have played a key role in triggering the pandemic. The findings, published in the journal Cell, suggest these fox-like creatures could have been carriers of the virus that caused global devastation, with the infamous Wuhan market serving as ground zero for the deadly spillover from animals to humans.
The research delves into genetic material gathered from the Huanan Seafood Wholesale Market in Wuhan, China, in early 2020, where the first cases of COVID-19 were identified. Investigators found genetic traces of raccoon dogs and other animals susceptible to the virus, such as civets and marmots, mixed with the viral RNA of SARS-CoV-2. The analysis points to a specific section of the market, Stall A, as a hotbed of animal-to-human transmission, placing these creatures at the centre of the pandemic’s origin story.
The authors of the study, a team of leading virologists and geneticists, argue that this new evidence adds weight to the theory that the virus jumped from wildlife to humans in the market, rather than escaping from a laboratory. Kristian Andersen, one of the paper’s authors and a prominent voice in the COVID origins debate, said, “This doesn’t prove infected animals were at the market, but it’s the most likely scenario. The data we analysed shows a clear overlap between the virus and genetic material from raccoon dogs and other animals at the time.”
Stall A: The Virus Hotspot
The study, led by scientists including Michael Worobey and Angela Rasmussen, used metagenomic data collected by Chinese researchers from the market in early 2020. The samples, which were taken from surfaces like cages, carts and the floors of market stalls, were re-analysed by the international team. In Stall A, the southwest corner of the market, they found the strongest genetic signals of SARS-CoV-2 alongside DNA from animals like raccoon dogs.
Photographs taken years before the pandemic, in 2014, show raccoon dogs and other exotic species caged for sale in this very section. These images, combined with the new genetic evidence, paint a picture of a market brimming with animals capable of transmitting the virus. The presence of these animals, now confirmed, dismisses any doubts about whether they were sold at the market during the critical period when COVID-19 first appeared.
The study suggests that raccoon dogs, which are known to be highly susceptible to SARS-CoV-2, may have been the carriers of the virus that infected humans. The researchers believe that the virus likely spilled over from these animals to people working at or visiting the market. This hypothesis aligns with earlier theories that wild animals sold in the crowded, unhygienic environment of the wet market provided the perfect conditions for the virus to jump species.
Raccoon Dogs and the Viral Link
Raccoon dogs, native to East Asia, are a common sight in China’s wildlife trade. They are bred for their fur and often sold live at markets, making them prime candidates for spreading zoonotic diseases. The new study shows that raccoon dogs were present in high numbers at the Wuhan market, and their genetic material was found in samples that also tested positive for SARS-CoV-2. This co-occurrence strongly suggests that these animals could have been the intermediate hosts that passed the virus from bats or another species to humans.
The researchers were able to reconstruct the complete mitochondrial genomes of several animals from the market, including raccoon dogs, civets, and bamboo rats. In one particularly telling sample, they found that the genetic material from raccoon dogs was far more abundant than human genetic material. This discovery supports the theory that these animals were harbouring the virus before it made the leap to humans.
Worobey, head of the Department of Ecology and Evolutionary Biology at the University of Arizona, was emphatic in his conclusions: “If COVID-19 didn’t originate at the market, the presence of this genetic material in exactly the right place at the right time would be an incredible coincidence. The evidence is mounting that wildlife in the market, particularly raccoon dogs, played a significant role in the pandemic’s origins.”
The Lab Leak Debate Rages On
Despite the compelling evidence, not everyone is convinced. Critics of the market-origin theory, including those who argue that the virus may have leaked from the Wuhan Institute of Virology, have been quick to point out flaws in the new study. Jamie Metzl, an outspoken advocate of the lab-leak hypothesis, claims the data used by the researchers is biased. He argues that the swabs collected from the market were taken only from specific areas known to sell live animals, creating a false narrative that links the virus to wildlife.
Metzl said, “This study doesn’t prove anything definitively. The data is flawed, and the time line the authors propose is questionable. It’s important to remember that this is still a contested issue, and there are serious gaps in the evidence.”
Supporters of the lab-leak theory point to a 2022 report by Jesse Bloom, an evolutionary biologist, which found no clear link between any specific animal species and the presence of SARS-CoV-2 in the market. They argue that the virus could have been introduced into the market by infected humans and spread among workers and shoppers, rather than originating from wildlife.
Unanswered Questions
While the new study offers crucial insights into the early days of the pandemic, it leaves many questions unanswered. The biggest challenge is the lack of direct evidence showing that any specific animal at the market was infected with SARS-CoV-2. Since the market was shut down and cleared of wildlife shortly after the outbreak began, it’s impossible to test the animals that were present at the time.
Moreover, the study acknowledges that the data set is imperfect. The swabs were collected weeks after the virus had begun spreading, meaning some of the evidence may have been lost. Still, the researchers argue that the overwhelming presence of animal genetic material in SARS-CoV-2 positive samples, particularly from raccoon dogs, cannot be ignored.
Worobey summed up the significance of the findings, saying, “We don’t have a video of a civet sneezing on a market worker, but we have a remarkable amount of genetic data that points to this market as the likely source of the pandemic. It’s a stark reminder of the dangers of mixing wildlife with humans in these environments.”
As the debate over COVID-19’s origins continues, the raccoon dog has emerged as a key figure in the mystery. With over 6.9 million lives lost to the pandemic globally, this new evidence could be a crucial step towards finally understanding how the virus began.
* Image shows Wuhan Market. Credit: File.