Coronavirus pandemic originated from illegally traded wild animals in Wuhan: Research

World Friday 24/March/2023 08:30 AM
Coronavirus pandemic originated from illegally traded wild animals in Wuhan: Research

Wuhan : A recently released report by Chinese investigators has described in detail for the first time evidence that illegally traded wild animals triggered the coronavirus pandemic, reported The New York Times.

A team of Chinese investigators on January 12, 2020, combed a market for clues regarding the emergence of a strange new illness in the city of Wuhan. The team found that the cages typically used for transporting animals had tested positive for coronavirus.

The genetic material from that swab, which was covertly uploaded to a global database and only made public this year, has been examined by a group of international specialists three years later. The scientists, in a study that was made public on Monday night, said the swab evidence supports their contention that the coronavirus pandemic was started by illegally traded wild animals.

After being approached by the international team, the Chinese researchers who had uploaded the raw data requested that it be taken down from the database. In response to what they claimed were rules violations, database administrators have now denied access to the international researchers, raising concerns about the database's own role in the struggle for access to information that could provide insight into the origins of a virus that has killed seven million people.

According to a report published in The New York Times, the swab from the cart held more than 4,500 lengthy fragments of raccoon dog genetic material in addition to coronavirus genetic signatures, the report stated. There were none from people.

According to the study, some Covid-positive swabs from other items and market surfaces also contained more genetic material from animals than from people.

Animals themselves were not necessarily infected just because genetic material from the virus was discovered in the same location as animal genetic traces. Some scientists who read the report, however, noted that the prevalence of genetic material from animals, particularly raccoon dogs, indicated that species known to be able to spread the coronavirus were in fact carrying infections at market in late 2019.

They claimed that scenario, which was similar to the ones that led to the first SARS epidemic in China two decades earlier, was consistent with virus spreading into humans from market animals and sparking pandemic.

Theodora Hatziioannou, a virologist at The Rockefeller University in New York, who was not involved in the research, said, "You look at them and say those are probably infected animals," adding, "If it was a human shedding the virus, one would expect to find human DNA there, too."

More information about the origins of the virus in the samples may still be found in the swab. For instance, the report stated that there was proof of specific genes that might indicate the substance originated from a raccoon dog's upper respiratory tract, reported The New York Times.

However, even if an animal had the disease, it might not be obvious that it had exposed humans to the infection. A market animal might have fallen ill from someone who was afflicted with the virus. And since the market was cleared of animals shortly after the outbreak started, scientists were unable to determine whether an animal had been infected by swabbing it directly.

The report has been the focus of intense speculative discussion ever since the international experts presented their findings to the World Health Organization last week and then hurried to assemble their analyses. The discoveries also sparked a fight over access to the genetic codes that underlie them.

After publishing a paper describing them last year, Chinese researchers first uploaded the raw sequences to a global database. However, the material was taken offline after the international experts made their discovery in early March and informed Chinese researchers of it.

A report published in The New York Times read, the WHO censured China last week for three years of keeping such important information secret from the rest of the world. The Munich-based nonprofit GISAID, which manages the database, is currently under fire for its involvement in regulating data access.

The international team of scientists claimed that by allowing the Chinese researchers to withhold the data for such a prolonged period of time, GISAID had "deviated from its stated mission," according to the new report.

In response to the story on Tuesday, the database administrators disabled the team members' access to their online accounts and claimed they had broken the rules by posting their own analysis before the Chinese scientists had even finished.

The researchers claimed that in downloading and analyzing the sequences, they adhered to the terms of the GISAID database access agreement. They also mentioned that they had extended numerous invitations to collaborate with the Chinese researchers.

Michael Worobey, an evolutionary biologist at the University of Arizona and a co-author of the new report, noted that GISAID also jeopardized team members' work related to coronavirus variants and flu preparedness, adding that "the ramifications of cutting off access to this group of authors are huge." "They're accusing you in error."

Because so much of the animals' genetic material was discovered in the key swab from the cart and because they are known to transmit viruses, the international team zeroed in on raccoon dogs, fluffy mammals related to foxes that are sold for their flesh and fur.

They claimed that their research supported the theory that the virus, which had its origins in bats, was being carried by the animal and being transmitted to people at the market.

Joel Wertheim, an evolutionary biologist at the University of California, San Diego and a co-author of the study, said of the new genetic information, "This isn't an infected animal." But without the animal in front of you, this is the nearest you can get, The New York Times reported.

Kristian Andersen, a virologist at the Scripps Research Institute in La Jolla, California, and a co-author of the report, however, noted that the report also provided the most conclusive proof of other animals susceptible to the virus being sold at the market to this point.

Additionally, swabs that tested positive for the coronavirus contained genetic material from those animals, including the masked palm civet, a small Asian mammal that was connected to the SARS epidemic 20 years ago.

Regarding the variety of animals listed in the report, Joseph DeRisi, a professor of biochemistry at the University of California, San Francisco and the head of the Chan Zuckerberg Biohub, said, "It's literally Disney Land for zoonotic transfer."

Large amounts of human genetic material were discovered in several other swabs from the market, which the study said was evidence that some virus samples were probably being shed by infected individuals. Many of the earliest known Covid patients either worked or shopped at the market.

According to the study, genetic material from animals not thought to be virus susceptible predominated in other positive swabs. For instance, a sample obtained from the surface of fish packaging revealed a significant amount of fish genetic material. Scientists concluded that the virus was probably human-deposited, demonstrating that the presence of large quantities of animal genetic material did not imply that the virus was created by animals in that location.

Some scientists cited those results in claiming that the types of swabs examined in the study simply could not provide concrete evidence of an infected animal.

According to Sergei Pond, a virologist at Temple University in Philadelphia, "The report does contain useful information." But did it reveal anything about which mammal was infected, he continued? Really, it doesn't.

Microbiologist Dr David Relman of Stanford said that without additional information on the methods used by the Chinese researchers to collect and analyze their swabs, it was impossible to evaluate the results. He pointed out that the Chinese paper from the previous year detailed using a kit to remove human genetic material and increase the tests' sensitivity to the virus.

However, several of the swabs from the Chinese researchers that were mentioned in the report of the international team contained significant quantities of human genetic material, indicating that those filtering techniques had not removed all of the human material from the samples. Such kits were usually ineffective at erasing people's genetic signatures, according to Dr DeRisi, an expert in the kind of analysis detailed in the report.

The report's methodologies were sound, according to Frederic Bushman, a microbiologist at the University of Pennsylvania who also specializes in sequencing methods.

He stated, "I think the simplest answer is that it's an infected raccoon dog. "I don't think it's absolute proof," The New York Times reported.