FRIDAY, March 17, 2023 (HealthDay News) -- A new theory about the start of the COVID-19 virus points to illegally traded raccoon dogs at a market in Wuhan, China.
Genetic data from swabs connected to these fox-like animals with a raccoon face offers tangible evidence of the virus’ possible origin, according to an international team of virus experts.
These animals are known to be able to transmit the coronavirus, the New York Times reported.
A full report on the testing has not yet been published. The Atlantic first reported on the analysis.
The genetic data was collected on swabs starting in January 2020 from walls, floors, metal cages and carts used to move cages in and around the Huanan Seafood Wholesale Market after Chinese authorities closed it because of its potential link to the virus.
Large amounts of the genetic material were a match for the raccoon dog. Material from the raccoon dog and the virus were in the same places.
This evidence doesn’t mean that the raccoon dog was infected or that it spread the virus to people. It’s possible that a human spread the virus to the animal or that a different animal spread the virus to a person.
Researchers studied this using raw data from swabs that were posted to GISAID, an international repository of genetic sequences of viruses.
Chinese scientists had previously released a study using market samples in February 2022. It had reported samples positive for SARS-CoV-2, but suggested the virus came from infected shoppers or workers, rather than animals.
Those same researchers posted the raw data that international researchers used for their analysis.
Florence Débarre, an evolutionary biologist at the French National Center for Scientific Research in Paris, happened upon that data March 4. She set it aside and then logged in against last week, finding new data that virus experts had been waiting to see since the original study was published.
Débarre alerted an international team of researchers, who started mining the data last week, according to the Times.
Those researchers included Michael Worobey, an evolutionary biologist at the University of Arizona; Kristian Andersen, a virologist at the Scripps Research Institute in La Jolla, Calif., and Edward Holmes, a biologist at the University of Sydney in Australia.
“We were able to figure out relatively quickly that at least in one of these samples, there was a lot of raccoon dog nucleic acid, along with virus nucleic acid,” Stephen Goldstein, a University of Utah virologist who worked on the new analysis, told the Times.
Researchers were interested in a swab taken from a cart linked to a specific market stall that Holmes had visited in 2014, noting that it contained raccoon dogs in a cage on top of a cage that held birds. Such an environment is conducive to the transmission of new viruses.
When the team reached out to the Chinese researchers who had uploaded the data to offer to collaborate, the sequences disappeared from GISAID. It is not clear why this happened.
“What’s important is there’s still more data,” Débarre told the Times.
Some of the data was from market samples that were never made public. The samples included genetic material from other animals and from humans.
“We don’t have an infected animal, and we can’t prove definitively there was an infected animal at that stall,” Goldstein cautioned.
It's not clear when the genetic material was deposited at the market because genetic material can remain stable.
This information comes at a time when another theory is getting notice, that of the virus emerging from a leak at a research lab in Wuhan.
More information
The U.S. Centers for Disease Control and Prevention has more on COVID-19.
