Tag: China

The Evidence for The Animal Origins of COVID

Photo by Todd Cravens on Unsplash

An article in Science explores the evidence for the animal origin of COVID, which was first detected in December 2019, but inferred to be present in Hubei province, China, for about a month beforehand. 

The current COVID epidemic can be better understood by examining the severe acute respiratory syndrome coronavirus (SARS-CoV) outbreak which began in 2002. Investigations later found that horseshoe bats (Rhinolophus) in China harboured related coronaviruses. It was inferred that a sarbecovirus circulating in horseshoe bats seeded the progenitor of SARS-CoV in an intermediate animal host, most probably civet cats Although other possible intermediate hosts for SARS-CoV were identified, it is a population of civet cats within markets that appear to have acted as the conduits of transmission to humans from the horseshoe bat reservoir of SARS-CoV. Presumably a captive civet cat initially became infected by direct contact with bats or was infected before capture.

SARS-CoV-2 first emerged in Wuhan city, over 1500 km from the closest known naturally occurring sarbecovirus collected from horseshoe bats in Yunnan province. Coronaviruses genetically close to SARS-CoV-2 are circulating in horseshoe bats with wide geographic ranges indicate that the singular focus on Yunnan is misplaced. Confirming this assertion, the evolutionarily closest bat sarbecoviruses are estimated to share a common ancestor with SARS-CoV-2 at least 40 years ago, showing that these Yunnan-collected viruses are highly divergent from the SARS-CoV-2 progenitor. 

Though the virus may have jumped to humans from direct horseshoe bat–to–human contact, a known risk for SARSr-CoVs, the first detected SARS-CoV-2 cases in December 2019 are associated with Wuhan wet markets. This is consistent with multiple animal-market–associated spillover events in November and December (9). It is currently not possible to be certain of the animal source of SARS-CoV-2, but it is notable that live animals, including civet cats, foxes, minks, and raccoon dogs, all susceptible to sarbecoviruses, were for sale in Wuhan markets, including the Huanan market (identified as an epicenter of the outbreak in Wuhan) throughout 2019.

Together, this suggests a central role for SARSr-CoV–susceptible live intermediate host animals as the primary source of the SARS-CoV-2 progenitor that humans were exposed to, as was the case with the origin of SARS.

Spillover events are not so rare, indicated by evidence of SARSr-CoV–specific antibodies in people living in rural areas, and even higher rates recorded in people living near bat caves. When exposed a densely packed human population, such as in Wuhan city, these spillover events have a much higher chance of resulting in substantial onward spread 

Interestingly, the proximity of humans to wildlife may have been increased by demand for alternative meat sources caused by reduced availability of pork in 2019. This was caused by the African swine fever virus (ASFV) pandemic, which led to ∼150 million pigs being culled in China, resulting in a pork supply reduction of ∼11.5 million tonnes in 2019, and from which the country is still recovering. Increased use of cold-chain logistics in the wake of the ASFV pandemic means that frozen animal carcasses carrying SARS-CoV-2 may have been brought from much farther afield.

Once crossed over, SARS-CoV-2 readily established itself in humans by being a generalist, as opposed to being specialised for humans. Ironically, since humans are now the largest reservoir of the virus, animals in contact with humans are at risk of virus spillover. The article authors closed by stressing the need for much greater viral surveillance to spot emerging threats, as current coverage is extremely spotty.

Source: Science

China Reports First Human Infection of the H10N3 Avian Flu Strain

Image by Arek Socha from Pixabay

On Tuesday, China reported the world’s first human infection of the H10N3 avian flu strain but said the risk of its widespread transmission among people was low.

In the eastern city of Zhenjiang, a 41-year-old man was admitted to hospital with fever symptoms on April 28 and a month later was diagnosed with H10N3, China’s National Health Commission (NHC) said in an online statement.

The NHC said that “The risk of large-scale spread is extremely low,” and that the man was in a stable condition with his close contacts having reported no “abnormalities”.

The health body described H10N3 as being low pathogenic, ie less likely to cause death or severe illness, in birds. It said there had been no human cases of H10N3 previously reported anywhere in the world.

A number of strains of bird flu have been found among animals in China but mass outbreaks in humans are rare.

Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017. Low pathogenicity H7N9 dominated in the first four waves, whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave, causing widespread concern.  

H7N9 has infected 1668 people and claimed 616 lives since 2013, according to the United Nations’ Food and Agriculture Organization. In the wake of recent avian flu outbreaks in Africa and Eurasia, the head of China’s Centre for Disease Control and Prevention last week urged closer surveillance in poultry farms, markets and wild birds.

COVID was first detected at a wet market with food and live animals in the central Chinese city of Wuhan in late 2019. This is where, according to the most likely scenario from the WHO report on the virus’ origins, it is thought that the SARS-CoV-2 virus first jumped from animals to humans. 

Source: Medical Xpress

President Biden Orders Deeper Probe into COVID Origins

Photo by Giacomo Carra on Unsplash


US President Joe Biden has ordered intelligence officials to “redouble” their efforts in investigating the origins of COVID, as well as the theory that it was a ‘lab leak’ in China.

This comes days after details of a US intelligence report emerged in the Wall Street Journal, claiming that three doctors working at the Wuhan Institute of Virology had fallen ill with COVID-like symptoms in November 2019 – about when epidemiologists believe SARS-CoV-2 first began circulating in humans. 

Mr Biden said the US intelligence community was divided on whether it was the result of a lab accident, or from jumping from human to animal. Mr Biden asked the groups to report back to him within 90 days.

China’s embassy in the US made a warning statement posted on its website, without mentioning the president’s remarks. “Smear campaigns and blame shifting are making a comeback, and the conspiracy theory of ‘lab leak’ is resurfacing.
“To politicise origin tracing, a matter of science, will not only make it hard to find the origin of the virus, but give free rein to the ‘political virus’ and seriously hamper international cooperation on the pandemic,” it said.

Authorities linked early COVID cases to a seafood market in Wuhan, leading scientists to theorise the virus first passed to humans from animals.

Why now?

In a White House statement released on Wednesday, President Biden said he had asked for a report on the origins of COVID after taking office, “including whether it emerged from human contact with an infected animal or from a laboratory accident”. He asked for “additional follow-up” on receiving the report.

Mr Biden said most of the intelligence community had “coalesced” around those two scenarios, but “do not believe there is sufficient information to assess one to be more likely than the other”.

The president has now asked agencies to “redouble their efforts to collect and analyse information that could bring us closer to a definitive conclusion”, and report to him within 90 days.

He concluded by saying the US would “keep working with like-minded partners around the world to press China to participate in a full, transparent, evidence-based international investigation and to provide access to all relevant data and evidence”.

Beijing meanwhile has previously suggested a possible US lab origin for COVID. The Chinese embassy said it supported a full investigation into “some secretive bases and biological laboratories all over the world”.

Mr Biden’s statement coincided with a CNN report that the president’s administration earlier this year shut down a state department investigation into a possible lab leak origin.

The ‘lab leak’ theory

When they first arose last year, the laboratory leak allegations were widely dismissed as a fringe conspiracy theory, with many US media outlets describing the claims as debunked or false after then-President Donald Trump said COVID had originated from the Wuhan Institute of Virology.

Two months ago, the World Health Organization (WHO) issued a joint report with Chinese scientists on COVIDs origins, rating the likelihood of an accidental lab release as “extremely unlikely”. However the WHO Director-General Tedros Adhanom Ghebreyesus said that he was not satisfied that the investigation had looked at this possibility enough to rate. The investigation only stirred up more interest in the ‘lab leak’ theory, with 18 scientists signing an open letter calling for more investigation before it could be ruled out.

There is little evidence for the ‘lab leak’ theory in the public domain however, and intelligence reports such as the one the Wall Street Journal based its story on are often of unproven provenance. 

Chief White House medical adviser Anthony Fauci still believes that COVID jumped from animals to humans, though this month he admitted he was no longer confident COVID had developed naturally.
Mounting pressure

Mr Biden’s statement comes the day after Xavier Becerra, US secretary for health and human services, urged the WHO to ensure a “transparent” investigation into the virus’s origins.

“Phase 2 of the Covid origins study must be launched with terms of reference that are transparent, science-based and give international experts the independence to fully assess the source of the virus and the early days of the outbreak,” Mr Becerra said.

On Tuesday, Mr Trump sought to take credit in an emailed statement to the New York Post, saying: “To me it was obvious from the beginning but I was badly criticised, as usual. Now they are all saying: ‘He was right.'”

Source: BBC News

‘Lab Leak’ Theory Gains Ground with Report of Sick Wuhan Lab Staff in 2019

Image source: CDC/Unsplash

As reported by the Wall Street Journal, US intelligence learned three doctors at Wuhan Institute of Virology became sick with COVID-like symptoms in November 2019 and sought out hospital care. This, along with an open letter in the journal Science has prompted new calls to find out whether COVID started at that facility. 

A State Department report was issued during the last days of former President Donald Trump’s administration but officials familiar with the report did not agree on the strength of the evidence found, the Journal reported. However this new report adds more detail, and comes on the eve of a World Health Organization meeting, which will no doubt include COVID.

In March, virologist Marion Koopmans told NBC News that the illness of lab workers could be due to normal seasonal illnesses.

Earlier this year, a team from the WHO spent a month in Wuhan investigating the origin of the virus, and produced a report concluding that the virus most likely jumped from bats to people, rating a lab leak as “extremely unlikely”.

The WHO however also said it also did not have access to all the necessary information – a situation has prompted some experts to be wary of the findings and demand more investigations into the virus’s origin, including the possibility that it in fact was leaked from a lab.

November 2019 is also in line with when experts believe COVID began circulating.

For its own part, China has consistently denied that the coronavirus escaped from a lab. However, the lab has not made available its raw data or records on its work with coronaviruses in bats.

A spokeswoman for the National Security Council told the Wall Street Journal that the Biden administration has questions about the virus’, but plausible theories should be investigated by WHO.

“We’re not going to make pronouncements that prejudge an ongoing WHO study into the source of SARS-CoV-2,” the spokeswoman said. “As a matter of policy we never comment on intelligence issues.”

Source: Business Insider

Scientists Urge Deeper Look into Possible ‘Lab Escape’ Origin of COVID

Computer image of SARS-CoV-2. From CDC at Pexels

In a letter in the journal Science, eighteen scientists from world-leading research institutions are urging their colleagues to dig deeper into the origins of the coronavirus responsible for the global pandemic. 

They argue that there is still not enough evidence to rule out the possibility that the SARS-CoV-2 virus escaped from a lab in China, and they call for a “proper investigation” into the matter.

“We believe this question deserves a fair and thorough science-based investigation, and that any subsequent judgment should be made on the data available,” said Dr. David Relman, professor of microbiology and immunology at Stanford University who helped pen the letter.

They were motivated partly by the March 30 publication of a report commissioned by the World Health Organization that sought to discover the origin of the SARS-CoV-2 virus.

The report’s authors, jointly credited to the WHO and China, ranked each of four possible scenarios on a scale from “extremely unlikely” to “very likely.” After assessing evidence provided by the Chinese team members, the authors concluded the probability that the virus jumped from animal to humans via an intermediary animal was “likely to very likely,” while an accidental laboratory release was deemed “extremely unlikely.”

Other potential pathways the investigators considered were a direct jump from animal to human without an intermediate host (“possible to likely”) and transmission from the surface of frozen food products (“possible”).

But Relman and his co-authors said the WHO investigators did not have enough information to reach these conclusions.

“We’re reasonable scientists with expertise in relevant areas,” Relman said, “and we don’t see the data that says this must be of natural origin.”

Ravindra Gupta, a professor of clinical microbiology at the University of Cambridge who signed the letter, said he would like to review lab notes from scientists working at the Wuhan Institute of Virology, and see a list of viruses used at the institute over a five-year period.

The WHO report documents a meeting between its investigators and several members of the institute, including lab director Yuan Zhiming, who gave the joint team a tour of the facility.

At the meeting, representatives of WIV refuted the possibility that SARS-CoV-2 could have leaked from the lab, noting that none of the three SARS-like viruses cultured in the laboratory are closely related to that virus.

They also pointed out that blood samples obtained from workers and students in a research group led by Shi Zhengli, a WIV virologist who studies SARS-like coronaviruses that originate in bats, contained no SARS-CoV-2 antibodies, which would indicate a current or past infection.

However, Relman said that, as a scientist, more than this thirdhand account was needed for him to exclude the possibility of of an accidental laboratory leak.

“Show us the test you used: What was the method? What were the results and the names of the people tested? Did you test a control population?” Relman said. “On all accounts, it was not an adequate, detailed kind of presentation of data that would allow an outside scientist to arrive at an independent conclusion.”

WHO Director General Tedros Adhanom Ghebreyesus was similarly cautious about the report’s findings.

“Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy,” he said in an address to WHO member states on March 30. “Let me say clearly that, as far as WHO is concerned, all hypotheses remain on the table.”

Michael Worobey, who studies viruses at the University of Arizona to better understand pandemics, also signed the letter. From the beginning of the pandemic, he considered that it was either an escape from a lab or natural transmission from animal to human. His stance is still unchanged.

“There just hasn’t been enough definitive evidence either way,” he said, “so both of those remain on the table for me.”

Worobey works in his own lab with a grad student who collects viruses from bats in the wild, and he’s considered how this kind of work could introduce new pathogen to humans.

“As someone who does this, I’m very aware of the opening that creates for new viruses to get close to humans, and so I think that’s another reason I take this seriously,” he said. “I’m concerned about it in my own work.”

SARS-CoV-2 has been shown not to be a laboratory construct genetically modified to make it more transmissible to humans, Worobey said. But an unmodified virus could have been brought into the lab and then moved into humans.

“I’ve seen no evidence that I can look at and say, ‘Oh, OK, this certainly refutes the accidental lab origin and makes it virtually 100% certain that it was a natural event,'” he said. “Until we’re at the stage, both possibilities are viable.”

Scientists said there was one piece of conclusive evidence that would indicate the virus had indeed spread to humans through a natural event—the discovery of the wild animals in whom the virus originated.

Akiko Iwasaki, a professor of immunobiology and epidemiology at Yale University, noted that the WHO report mentioned the testing of more than 80 000 animal samples collected across China. None of those tests turned up a SARS-CoV-2 antibody or snippet of the virus’ genetic material before or after the SARS-CoV-2 outbreak in China.

“However, it is possible that an animal reservoir was missed and further investigation may reveal such evidence,” said Iwasaki, another signatory to the letter.

David Robertson, the head of viral genomics and bioinformatics at the University of Glasgow had not signed the letter, saying he didn’t understand the point.

“Nobody is saying that a lab accident isn’t possible—there’s just no evidence for this beyond the Wuhan Institute of Virology being in Wuhan,” he said, adding that viruses naturally jump from animals to humans all the time.

Although he agreed with the authors of the letter that it was essential to find the origins of SARS-CoV-2 to prepare for the next pandemic, “wasting time investigating labs is a distraction from this,” he said.

Relman disagrees.

“If it turns out to be of natural origin, we’ll have a little bit more information about where that natural reservoir is, and how to be more careful around it in the future,” he said. “And if it’s a laboratory, then we’re talking about thinking much more seriously about what kinds of experiments we do and why.”

The letter’s authors noted that in this time of anti-Asian sentiment in some countries, it was Chinese doctors, scientists, journalists and citizens who shared with the world crucial information about the spread of the virus.

“We should show the same determination in promoting a dispassionate, science-based discourse on this difficult but important issue,” they wrote.

Source:
Medical Xpress

Journal information: Jennifer Sills et al. Investigate the origins of COVID-19, Science (2021). DOI: 10.1126/science.abj0016

Delaying Lumbar Puncture Cuts Relapse in Childhood Leukaemia

Commencing chemotherapy several days before the first lumbar puncture for diagnosis and treatment of acute lymphoblastic leukaemia (ALL) may lower the risk of central nervous system (CNS) relapse in children, according to a study from St Jude Children’s Research Hospital and collaborators in China. 

“This study identified factors to help us predict and better manage the risk of CNS relapse that will be useful for treating ALL patients worldwide, in both resource-rich and resource-limited countries,” said corresponding author Ching-Hon Pui, MD, chair of the St. Jude Department of Oncology. Dr Pui pioneered paediatric ALL treatment that has achieved 94% long-term survival for St. Jude patients that did not receive brain irradiation.

Using an adapted paediatric protocol from St Jude Hospital, 7640 children and adolescents across 20 Chinese hospitals were enrolled in the trial. However, there was a great disparity across the hospital settings. For example, just three of the hospitals offered total intravenous anaesthesia for children undergoing spinal taps, while only two had flow cytometry for the diagnosis of leukaemia cells in cerebrospinal fluid.

The five-year overall survival rate was 91% for study patients, and the cancer-free survival rate was 80%, which is a dramatic improvement over previous clinical trials in China. But 1.9% of patients relapsed in the CNS alone, and in another 2.7% of patients the relapse involved the CNS. In comparison, a Canadian study reported a 6.6% rate for CNS-involved relapse in paediatric ALL patients followed over 10 years.

According to Dr Piu, in order to increase the survival rate of paediatric ALL patients requires identifying those at risk for CNS relapse, along with increasing their quality of life. Three factors reduced the risk of CNS relapse. First, commencing dexamethasone a few days before the spinal tap, prevents leukaemia cells entering the cerebrospinal fluid (CSF). Second, intravenous anaesthesia reduced bleeding risk during lumbar punctures, and improved  intrathecal therapy. Third, flow cytometry enables more accurate diagnosis of leukaemia cells in CSF, and reduced CNS relapse.

Source: Medical Xpress

Journal information: Jingyan Tang et al. Prognostic Factors for CNS Control in Children with Acute Lymphoblastic Leukemia Treated Without Cranial Irradiation, Blood (2021). DOI: 10.1182/blood.2020010438

WHO Team Arrives in China for COVID Origin Investigations

Following months of negotiations, and then a list minute hiccough when two team members were denied entry last week, a team of 10 specialists from the WHO arrives in China to carry out their investigations into the origins of COVID.

China, through rapid action and total lockdowns, managed to clamp down on the coronavirus outbreak inside its borders, preventing it from spreading significantly outside of Wuhan, while in Wuhan itself, life has largely returned to normal. In recent weeks, however, new cases have been appearing in Hebei province around Beijing and in Heilongjiang province in the northeast.

Just before travelling, team leader Peter Ben Embarek told AFP news agency that it “could be a very long journey before we get a full understanding of what happened”.

He cautioned against expecting instant results, saying, “I don’t think we will have clear answers after this initial mission, but we will be on the way,” he said.

For a number of months, China has been saying that the virus may not have originated in Wuhan. There has been a lot of unsubstantiated speculation that the SARS-CoV-2 might have been accidentally released from a lab.

Prof Dale Fisher, chair of the global outbreak and response unit at the WHO, told the BBC that he hoped the rest of the world would regard this as a scientific visit. “It’s not about politics or blame but getting to the bottom of a scientific question,” he said.

When the WHO team arrives in China, they will still have to wait through a two week quarantine. Fabian Leendertz, a professor in the epidemiology of highly pathogenic microorganisms at Germany’s public health institute and working remotely with the team, says that their plan of action will be developed over the next two weeks while they are still in quarantine. The team is expected to look at the infamous wet market in Wuhan where it was originally believed the virus made the jump from animals to humans, as well as working with Chinese colleagues and local clinics to establish a picture of the virus’ origins.

Source: BBC News

WHO Team Barred from Entry into China

According to the World Health Organization, its team sent to China to investigate the origins of COVID were denied entry.

Conveying his disappointment at the team being barred from entry into China due to visas not being issued, WHO Director-General Tedros Adhanom Ghebreyesus said, “today, we learned that Chinese officials have not yet finalized the necessary permissions for the team’s arrival in China.”

Addressing the media in Geneva, he continued, “I’m very disappointed with this news, given that two members had already begun their journeys and others were not able to travel at the last minute, but had been in contact with senior Chinese officials.”

“But I have been in contact with senior Chinese officials. And I have once again made it clear that the mission is a priority for WHO and the international team.” He added, “We are eager to get the mission underway as soon as possible.” 

The experts were to investigate the origins of the SARS-CoV-2 virus in Wuhan.  The team of 10 will be led by Peter Ben Embarek, WHO’s expert on zoonoses – diseases that cross over the species barrier into humans from animals.

Dr Michael Ryan, the emergencies chief at WHO, said the understanding was that the team would begin the deployment from Tuesday, and that two of its members had begun travelling to China, with one member already turned back due to visa issues while the other was still in transit.

“We did not want to put people in the air unnecessarily if there wasn’t a guarantee of their arrival in China being successful,” said Ryan. “Dr Tedros has taken immediate action and has spoken with senior Chinese officials and has fully impressed upon them the absolute critical nature of this.”
“We hope that this is just a logistical and bureaucratic issue that can be resolved very quickly,” he continued.

According to the The Financial Times, Hua Chunying, the Chinese foreign ministry spokesperson, on Wednesday said, “Tracing the source [of the virus] is a complicated issue. To ensure that the international team’s work progresses smoothly, they must go through the necessary procedures.”

Source: The Independent