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Liang Wannian, the Chinese co-leader of the joint China-WHO investigation into the origins of the Covid-19 pandemic, urges WHO to reconsider transmission methods of Sars-CoV-2, saying it could be transmitted from humans or animals to objects and objects back to humans. Photo: AP Photo

Exclusive | Coronavirus origins: virus may have jumped to humans outside China, says expert leading China’s WHO team

  • Liang Wannian says during the next stage, inquiry should look to countries with coronavirus-infected animals and also those with cold-chain exports
  • He says there must be more study of animals raised for food or fur production, such as ferret-badgers, raccoons, civets and mink
The next step in tracing the origins of the new coronavirus responsible for the ongoing pandemic should be directed at countries where the virus had been found in animals, the environment and human samples earlier than the Wuhan outbreak in 2019, and the inquiry should also take in countries that exported cold-chain products to the city’s Huanan Seafood Market, according to the scientist who led the Chinese team during the World Health Organization’s origins investigation.

Responding exclusively to the South China Morning Post, Liang Wannian, a professor with the Vanke School of Public Health at Tsinghua University who was China’s key expert leading the joint investigation with the WHO earlier this year, said Wuhan might not be where Sars-CoV-2 – the virus that causes Covid-19 – jumped to humans.

He suggested that the UN agency conduct the next stage of its study in countries where transmission of the virus had been identified as happening before it was recognised in Wuhan.

Covid-19 came to the public’s attention in late December 2019, when a cluster outbreak of a mysterious pneumonia of unknown origin was identified by the Wuhan health care system, mostly among workers and customers of the Huanan Seafood Market. How the virus was introduced to the market remains unknown.

“We recommend that WHO conduct a review and analysis of earlier suspected cases, earlier evidence found in animal and environmental studies that were published, to determine the scientific validity and reliability of the available evidence,” Liang said in a written interview.

“The focus of phase 2 should be based on publicly available research evidence. As the pathway of virus transmission from natural hosts via intermediate hosts is the most likely, studies should be conducted in all countries where horseshoe bats and pangolins are distributed, particularly in areas where sampling is under-tested.”

Liang’s comments come just a week after US Secretary of State Antony Blinken met WHO Director General Tedros Adhanom Ghebreyesus in Kuwait and pledged his support for the UN agency’s investigation in China into the origins of the coronavirus pandemic.

Bats are a natural reservoir of coronaviruses, and the closest relative to Sars-CoV-2 is a coronavirus first identified in horseshoe bats in a cave in Mojiang, Yunnan, in 2013 by Shi Zhengli and her team at the Wuhan Institute of Virology. But genome sequencing shows a 96 per cent similarity, suggesting they are decades apart in evolution.

Several other coronaviruses have been found in horseshoe bats – such as in two Shamel’s horseshoe bats captured in Cambodia in 2010 with 92 per cent similarity – and pangolin coronaviruses show between 85 per cent and 92 per cent genomic similarity to Sars-CoV-2.

Liang added that countries in which evidence had been identified through the described comprehensive assessment and where animals had tested positive for Sars-CoV-2, as well as countries that supplied cold-chain products to the Huanan Seafood Market, should also undertake origin tracing, Liang added, citing various studies that suggested the coronavirus could have been spreading in Europe or the United States as early as November.

These studies included a skin graft from November 2019 in Milan, Italy, that tested positive for the virus, a waste water study indicating the virus could have been circulating in Brazil in the same month, and blood samples suggesting the coronavirus might have infected a small number of people in the US and France earlier than it was officially recognised in Wuhan.

No entry: the trouble ahead in China for the WHO’s Covid-19 origins hunt

The next phase of Sars-CoV-2 origin tracing has become a deadlock issue after the WHO proposed last month to conduct “audits of relevant laboratories and research institutions operating in the area of the initial human cases identified in December 2019”.
It would open another round of scrutiny for high-biosecurity laboratories in Wuhan that China had hoped to avoid after earlier investigations concluded that Sars-CoV-2 escaping from a lab was “extremely unlikely”.

Other directions proposed by WHO for next-phase studies still centre on China, including “studies of animal markets in and around Wuhan, including continuing studies on animals sold at the Huanan wholesale market”.

Another focus, according to the WHO, prioritises “geographic areas with the earliest indication of circulation of Sars-CoV-2, and neighbouring areas where other Sars-related coronaviruses have been found in non-human reservoirs”.

Tedros has said he expected China to support the second-phase investigation when presenting the proposal to member states, but it was rejected by Beijing, which called it “arrogant” and “disrespectful for common sense” with its return to the lab-leak hypothesis.

China filed its own proposal before the WHO Secretariat circulated its proposal, which, according to foreign ministry spokesman Zhao Lijian, suggested basing the second-phase study on the conclusions and recommendations of the joint WHO-China study report issued in March, with a focus on exploring the “very likely” pathways of natural occurrence through an intermediate animal host and the “likely” pathway of cold-chain products, according to Zhao.

Chinese scientists and officials favour the theory that a natural spillover event caused the Covid-19 pandemic and have raised the hypothesis that the virus was brought into China from abroad, perhaps on frozen food packaging. That was deemed “likely” by the team of international and Chinese experts who visited Wuhan in January and they called for further research into the possibility.

China vs the WHO: where to look next in the hunt for Covid-19’s origins

The WHO-China report identified 20 countries – including Argentina, Australia, Brazil, Canada, Chile, France, Russia and the United States – as sources of cold-chain products sold in the Hunan Seafood Market before the outbreak, but the hypothesis was dropped from the WHO’s future study plan last month.

Liang suggested WHO reconsider the chain of transmission and transmission methods of Sars-CoV-2 “in the light of the latest research findings and keep abreast of the times”, citing that Sars-CoV-2 could be transmitted from humans or animals to objects and objects back to humans, which “updated our understanding of the transmission of respiratory infectious diseases” as Liang put it.

Liang said China was “fully capable of conducting its own research in origin tracing”. He said work on finding animal hosts of Sars-CoV-2 was carried out before the WHO field trip in China but all samples taken on farms that supplied Huanan Seafood Market came back negative. Antibody and coronavirus tests on livestock and wildlife animals collected between 2018 and last year also came back negative, Liang said.

Research within China on people and wildlife would continue, but Liang said an international cooperation mechanism was still needed to study and monitor wildlife species that carried diversified coronaviruses – including horseshoe bats, pangolins, civets, minks, ferrets and raccoons – for Sars-CoV-2 tracing, with a particular focus on interviews and serological tests.

“Bats are widely present in the world but most places have not studied them systematically. There are many animals besides bats that are susceptible to the Sars-CoV-2. Research in these bat areas is essential,” Liang said.

Surveillance of Sars-associated coronaviruses should be carried out on captive wildlife or domestic animals, including species raised for food or fur production, such as ferret-badgers, raccoons, civets and mink in countries where sampling is not yet available or was inadequate, he added.

Lab leak or nature? Debate heats up on origins of Covid-19 virus

Meanwhile, a paper about potential locations of the Sars-CoV-2 natural reservoir was published last week without peer review on the open access site ChinaXiv.org by researchers including Gao Fu, director of the Chinese Centre for Disease Control and Prevention, and Chinese members of the WHO-China joint mission, including Wang Qihui from the Chinese Academy of Sciences and Tong Yigang, professor at Beijing University of Chemical Technology.

The paper suggested next-phase studies be conducted where the distribution of horseshoe bats overlaps with that of pangolins, minks or other potential intermediary hosts.

The paper cited the theory that cross-species transmission of Sars-CoV-2 from the reservoir host to the intermediate host required that the two hosts live close to each other and share ecological links. Such places included Southeast Asia, southern China, India, Sub-Saharan Africa and southern Europe, the researchers wrote.

This article appeared in the South China Morning Post print edition as: Call to redirect origins probe to other countries
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