Post by Admin on May 28, 2021 2:11:59 GMT
What does China make of this?
China has hit back at suggestions the virus may have escaped from a laboratory by calling it a smear, and it has suggested the coronavirus may have have entered the country in food shipments from another country.
The Chinese government points to new research published by one of its leading virologists into samples collected from bats in a remote abandoned mine.
Prof Shi Zhengli - often referred to as "China's Batwoman" - a researcher at the Wuhan Institute, published a report last week revealing that her team had identified eight coronavirus strains found on bats in the mine in China in 2015. The paper says that coronaviruses from pangolins pose more of an immediate threat to human health than the ones her team found in the mine.
China's state media have accused the US government and Western media of spreading rumours.
"The public opinion in the US has become extremely paranoid when it comes to the origin of the pandemic," an editorial in the Communist Party-owned Global Times newspaper said.
Instead, the Chinese government has been pushing another theory: that the virus reached Wuhan on frozen meat from China or South-East Asia.
Is there another theory?
Yes, and it's called the "natural origin" theory.
This argues the virus spread naturally from animals, without the involvement of any scientists or laboratories.
Supporters of the natural origin hypothesis say Covid-19 emerged in bats and then jumped to humans, most likely through another animal, or "intermediary host".
That idea was backed by the WHO report, which said it was "likely to very likely" that Covid had made it to humans through an intermediate host.
This hypothesis was widely accepted at the start of the pandemic, but as time has worn on, scientists have not found a virus in either bats or another animal that matches the genetic make-up of Covid-19, casting doubt over the theory.
Why does this matter?
Given the massive human toll of the pandemic - which has now claimed the lives of 3.5 million people worldwide - most scientists think understanding how and where the virus originated is crucial to prevent it happening again.
If the "zoonotic" theory is proved correct, it could affect activities such as farming and wildlife exploitation. In Denmark, fears about the spread of the virus through mink farming led to millions of mink being culled.
But there are also big implications for scientific research and international trade if theories related to a laboratory leak or frozen food chains are confirmed.
And confirmation of a leak may also affect how the world views China, which has already been accused of hiding crucial early information about the pandemic, and place further strain on US-China relations.
"From day one China has been engaged in a massive cover-up," Jamie Metzl, a fellow at the Washington-based Atlantic Council who has been pushing for the lab-leak theory to be looked into, told the BBC.
"As the evidence for the lab-leak hypothesis grows, we should be demanding the full investigation of all origin hypotheses that's required."
But others cautioned against pointing the finger at China too quickly.
"We do need to be a bit patient but we also need to be diplomatic. We can't do this without support from China. It needs to be a no-blame environment," Prof Dale Fisher, of Singapore's National University Hospital, told the BBC.
Identification of a novel lineage bat SARS-related coronaviruses that use bat ACE2 receptor
Hua Guo, Ben Hu, Hao-rui Si, Yan Zhu, Wei Zhang, Bei Li, Ang Li, Rong Geng, Hao-Feng Lin, Xing-Lou Yang, Peng Zhou, Zheng-Li Shi
doi: doi.org/10.1101/2021.05.21.445091
Abstract
Severe respiratory disease coronavirus-2 (SARS-CoV-2) causes the most devastating disease, COVID-19, of the recent century. One of the unsolved scientific questions around SARS-CoV-2 is the animal origin of this virus. Bats and pangolins are recognized as the most probable reservoir hosts that harbor the highly similar SARS-CoV-2 related viruses (SARSr-CoV-2). Here, we report the identification of a novel lineage of SARSr-CoVs, including RaTG15 and seven other viruses, from bats at the same location where we found RaTG13 in 2015. Although RaTG15 and the related viruses share 97.2% amino acid sequence identities to SARS-CoV-2 in the conserved ORF1b region, but only show less than 77.6% to all known SARSr-CoVs in genome level, thus forms a distinct lineage in the Sarbecovirus phylogenetic tree. We then found that RaTG15 receptor binding domain (RBD) can bind to and use Rhinolophus affinis bat ACE2 (RaACE2) but not human ACE2 as entry receptor, although which contains a short deletion and has different key residues responsible for ACE2 binding. In addition, we show that none of the known viruses in bat SARSr-CoV-2 lineage or the novel lineage discovered so far use human ACE2 efficiently compared to SARSr-CoV-2 from pangolin or some of the SARSr-CoV-1 lineage viruses. Collectively, we suggest more systematic and longitudinal work in bats to prevent future spillover events caused by SARSr-CoVs or to better understand the origin of SARS-CoV-2.
China has hit back at suggestions the virus may have escaped from a laboratory by calling it a smear, and it has suggested the coronavirus may have have entered the country in food shipments from another country.
The Chinese government points to new research published by one of its leading virologists into samples collected from bats in a remote abandoned mine.
Prof Shi Zhengli - often referred to as "China's Batwoman" - a researcher at the Wuhan Institute, published a report last week revealing that her team had identified eight coronavirus strains found on bats in the mine in China in 2015. The paper says that coronaviruses from pangolins pose more of an immediate threat to human health than the ones her team found in the mine.
China's state media have accused the US government and Western media of spreading rumours.
"The public opinion in the US has become extremely paranoid when it comes to the origin of the pandemic," an editorial in the Communist Party-owned Global Times newspaper said.
Instead, the Chinese government has been pushing another theory: that the virus reached Wuhan on frozen meat from China or South-East Asia.
Is there another theory?
Yes, and it's called the "natural origin" theory.
This argues the virus spread naturally from animals, without the involvement of any scientists or laboratories.
Supporters of the natural origin hypothesis say Covid-19 emerged in bats and then jumped to humans, most likely through another animal, or "intermediary host".
That idea was backed by the WHO report, which said it was "likely to very likely" that Covid had made it to humans through an intermediate host.
This hypothesis was widely accepted at the start of the pandemic, but as time has worn on, scientists have not found a virus in either bats or another animal that matches the genetic make-up of Covid-19, casting doubt over the theory.
Why does this matter?
Given the massive human toll of the pandemic - which has now claimed the lives of 3.5 million people worldwide - most scientists think understanding how and where the virus originated is crucial to prevent it happening again.
If the "zoonotic" theory is proved correct, it could affect activities such as farming and wildlife exploitation. In Denmark, fears about the spread of the virus through mink farming led to millions of mink being culled.
But there are also big implications for scientific research and international trade if theories related to a laboratory leak or frozen food chains are confirmed.
And confirmation of a leak may also affect how the world views China, which has already been accused of hiding crucial early information about the pandemic, and place further strain on US-China relations.
"From day one China has been engaged in a massive cover-up," Jamie Metzl, a fellow at the Washington-based Atlantic Council who has been pushing for the lab-leak theory to be looked into, told the BBC.
"As the evidence for the lab-leak hypothesis grows, we should be demanding the full investigation of all origin hypotheses that's required."
But others cautioned against pointing the finger at China too quickly.
"We do need to be a bit patient but we also need to be diplomatic. We can't do this without support from China. It needs to be a no-blame environment," Prof Dale Fisher, of Singapore's National University Hospital, told the BBC.
Identification of a novel lineage bat SARS-related coronaviruses that use bat ACE2 receptor
Hua Guo, Ben Hu, Hao-rui Si, Yan Zhu, Wei Zhang, Bei Li, Ang Li, Rong Geng, Hao-Feng Lin, Xing-Lou Yang, Peng Zhou, Zheng-Li Shi
doi: doi.org/10.1101/2021.05.21.445091
Abstract
Severe respiratory disease coronavirus-2 (SARS-CoV-2) causes the most devastating disease, COVID-19, of the recent century. One of the unsolved scientific questions around SARS-CoV-2 is the animal origin of this virus. Bats and pangolins are recognized as the most probable reservoir hosts that harbor the highly similar SARS-CoV-2 related viruses (SARSr-CoV-2). Here, we report the identification of a novel lineage of SARSr-CoVs, including RaTG15 and seven other viruses, from bats at the same location where we found RaTG13 in 2015. Although RaTG15 and the related viruses share 97.2% amino acid sequence identities to SARS-CoV-2 in the conserved ORF1b region, but only show less than 77.6% to all known SARSr-CoVs in genome level, thus forms a distinct lineage in the Sarbecovirus phylogenetic tree. We then found that RaTG15 receptor binding domain (RBD) can bind to and use Rhinolophus affinis bat ACE2 (RaACE2) but not human ACE2 as entry receptor, although which contains a short deletion and has different key residues responsible for ACE2 binding. In addition, we show that none of the known viruses in bat SARSr-CoV-2 lineage or the novel lineage discovered so far use human ACE2 efficiently compared to SARSr-CoV-2 from pangolin or some of the SARSr-CoV-1 lineage viruses. Collectively, we suggest more systematic and longitudinal work in bats to prevent future spillover events caused by SARSr-CoVs or to better understand the origin of SARS-CoV-2.