SYDNEY — A leading Australian scientist who helped to map the Covid-19 genome has dismissed widespread speculation the novel coronavirus originated in a Chinese laboratory, insisting that scientific tracing tests show it came from a wildlife species rather than biological facility.
Edward Holmes, a biologist at the University of Sydney and a fellow of the respected Royal Society in London, said the Wuhan laboratory blamed by some for the pandemic does have specimens of the bat virus RaTG13, the closest relative of Covid-19 source SARS-CoV-2, but the two are not genetically linked.
RaTG13 strains, he says, are from the southern Chinese province of Yunnan, not the central city of Wuhan, the pandemic’s initial epicenter.
“There is no evidence that SARS-CoV-2, the virus that causes Covid-19 in humans, originated in a laboratory in Wuhan, China,” said Holmes, who is a specialist in evolutionary biology, said in an April 16 statement.
“Coronaviruses like SARS-CoV-2 are commonly found in wildlife species and frequently jump to new hosts. This is also the most likely explanation for the origin of SARS-CoV-2.”
That scientific conclusion will soon be tested in the political arena.
US President Donald Trump’s administration is now investigating rumors and conspiracy theories that the virus may have been accidentally released from the Wuhan lab, which is close to a wet market where China says the first Covid-19 infections were detected in late 2019.
Despite China’s persistent denials, Trump and US Secretary of State Mike Pompeo have talked up the theory, which has been fueled by rightwing TV networks like Fox News and over social media sites.
Criticized for his administration’s slow response to countering the virus, Trump has sought to deflect attention to China’s role in its spread. He has labeled Covid-19 the “China virus” and claims that it consorted with the World Health Organization (WHO) to cover up the extent of the threat.
Trump this week temporarily cut off US funding to the WHO, which he has argued is manipulated by Beijing.
“What we do know is we know that this [Covid-19] originated in Wuhan, China,” Pompeo said this week. “We know there is the Wuhan Institute of Virology just a handful of miles away from where the wet market was. The United States government is working diligently to figure it out.”
According to the Washington Post, US diplomatic cables from 2018 had raised concerns over safety standards and the handling of virus samples at the Wuhan Institute of Virology lab, but did not specify the breaches. It said samples of SARS had twice been leaked by unidentified Chinese labs.
Fox News this week contended that the Covid-19 pandemic “likely originated in a Wuhan laboratory, though not as a bioweapon but as part of China’s attempt to demonstrate that its efforts to identify and combat viruses are equal to or greater than the capabilities of the United States.”
One story doing the rounds in social media is that the virus emerged from research by China to produce biological weapons in the Wuhan lab, which is one of only a few dozen facilities worldwide that are designated BSL-4, the highest level of containment security for global research laboratories.
This means that it has been built to a standard where it would be capable of handling the worst pathogens known to mankind, including ebola and SARS strains, without safety being compromised.
The US government is a financial supporter of the lab, as are leading American research institutes; the 2018 diplomatic cables showd the US even recommended that funding be increased.
An American study of the Covid-19 genome published in Nature magazine in March [https://www.nature.com/articles/s41591-020-0820-9] found no indications that the virus had been engineered in a lab, either for the purposes of scientific research or nefarious motives.
“This is strong evidence that SARS-CoV-2 is not the product of purposeful manipulation,” said the study’s authors, who included the University of Sydney’s Holmes and scientists from research institutes in the US and Edinburgh in Scotland.
Genome tracing has revealed that the bat virus RaTG13 has at least 20 years of genetic divergence, or evolutionary change, from SARS-CoV-2, and possibly as much as 50 years, ruling it out as the source of the pandemic.
The US study also said there was evidence that SARS-CoV-2 was optimized for binding to a human receptor, probably as a result of natural selection.
Two scenarios were proposed for SARS-CoV-2: that it originated from natural selection in an animal host before zoonotic transfer (transmission to a human), or bypassed animals and was transferred directly to humans.
Supporters of the conspiracy theory have pointed out that the wet market does not actually sell bats, the supposed host of SARS-CoV-2, and that the first victim of the infection had no known connection with the market.
However, Holmes said this merely indicates how much researchers still don’t know about the coronavirus.
“In summary, the abundance, diversity and evolution of coronaviruses in wildlife strongly suggests that this virus is of natural origin,” Holmes said in the April 16 statement.
“However, a greater sampling of animal species in nature, including bats from Hubei province, is needed to resolve the exact origins of SARS-CoV-2,” Holmes said, noting that viruses related to SARS-CoV-2 were also found in pangolins.
China is doing its own research into the origins of Covid-19, but foreign ministry spokesman Zhao Lijian said at a press conference in Beijing that World Health Organization officials “have said multiple times there is no evidence the new coronavirus was created in a laboratory.”