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How did the COVID-19 pandemic start, where did the coronavirus come from, did it actually escape the lab? Experts from the WHO and the Chinese health commission searched for answers in Wuhan for over a month. One of the researchers was Dominic Dwyer from the University of Sydney. What exactly was discovered in the cradle of SARS-CoV-2, he described in “The Conversation”. There are three important points to note.
- In mid-January, a group of 10 international WHO experts traveled to Wuhan to cooperate with Chinese specialists
- Prof. Dwyer: Wuhan Market was a reinforcing factor rather than a true zero point of the pandemic. We have to look elsewhere
- SARS-CoV-2 could find its way to the Wuhan market due to infected people, contaminated animal products, cold chain products (chilled or frozen food)
- Coronavirus may have escaped from the lab? Here’s what the expert says
- You can find more such stories on the Onet homepage.
WHO experts are investigating the sources of the COVID-19 pandemic. Mission in Wuhan
After the outbreak of the coronavirus pandemic, everyone wondered what really happened, where did the new virus come from, whether it existed before, when it began to spread, whether its source is the Chinese Wuhan Market, or perhaps – as some theories put it – the Wuhan laboratory Institute of Virology (WIV). To get answers to these questions, you had to go to where it all began – the Chinese city of Wuhan.
According to the British media, the Chinese authorities had long delayed consenting to independent research into the sources of the pandemic and the arrival of international experts in the city. Negotiations with the World Health Organization lasted for many months. But it worked. In mid-January, a group of 10 international experts traveled to Wuhan to work with 17 specialists from the Chinese health committee.
Fabian Leendertz, a German biologist at the Institute of Infectious Diseases Robert Koch (RKI), of whom he was part of the group, emphasized that the aim of the research is not to determine who is to blame for the outbreak of a pandemic, but rather to prevent similar events in the future. – This is an attempt to understand what happened and whether we can try to reduce the risk in the future by using the collected data. He said.
The expert group also included Dominic Dwyer, an Australian microbiologist, professor of clinical immunology and infectious diseases at the University of Sydney. – We looked at clinical epidemiology (how COVID-19 spreads among humans), molecular epidemiology (the genetic makeup of the virus and its spread), and the role of animals and the environment (…) As part of the mission, we met a man who was the first confirmed case of COVID-19. We met doctors who worked in Wuhan hospitals, and while treating these early cases of infection, we learned what happened to them and their colleagues, he wrote in The Conversation.
What was discovered thanks to these activities? Prof. Dwyer reported on this in his article. Three important points stand out.
The commission’s research showed that SARS-CoV-2 is most likely of animal origin. – It probably passed to humans from bats via an as yet unknown animal intermediating in an unknown place – explains the microbiologist. He also points out that “samples taken from bats from Hubei province and wild animals in China have not yet revealed SARS-CoV-2”. Work is ongoing to establish the exact chain of events that led to the current pandemic.
- How is an epidemic different from a pandemic?
Many of the first infections detected with the new pathogen have been linked to the Wuhan seafood market. The commission visited the market that is now closed. Dominic Dwyer recalls that they sold, among others, animals raised for food – bamboo, civets, badgers, ferrets. There is also evidence that some domesticated wild animals may be susceptible to SARS-CoV-2. However, none of the animal products sampled after market close were positive for coronavirus, he stressed.
Nevertheless, the scientist admits that when he saw the market closed today, it was easy to see how the infection could spread there. – When it was open, it was visited by about 10. people a day, it was crowded, poor ventilation – he describes. Genetic studies of the coronavirus taken from those infected at a Wuhan market showed that they were identical, suggesting a transmission cluster (accumulation of more than the expected number of cases of the disease).
On the other hand, differences were seen in other viral sequences and this might indicate other unknown transmission chains. “ We also know that not all of the first 174 infected people have visited the market, ” Dwyer points out, adding that there are also publications that suggest SARS-CoV-2 was circulating in various countries even before the first case in Wuhan was identified, though, he points out. “They need to be confirmed”.
- 10 years ago, a virus similar to SARS-CoV-2 was discovered in Cambodia
What are the conclusions of all this? – The Wuhan market was a reinforcing factor rather than necessarily a true zero point of the pandemic. So we have to look elsewhere – says the expert.
The commission also verified the hypothesis that SARS-CoV-2 came from a different place, and that its spread was caused, among others, by processing, transporting, chilling or freezing food (ie the so-called “cold chain”). – Was it ice cream, fish, wild animal meat? We do not know. This has not been proven to produce the virus itself. But to what extent did he spread it? Again, we don’t know, the scientist admits.
Several cold chain products on the Wuhan market have not been tested for the presence of the coronavirus. However, tested samples from the market showed viral surface contamination. According to the microbiologist, this could mean that SARS-CoV-2 could have ended up there due to infected people, contaminated animal products and cold chain products. Research on this issue is ongoing.
“The most politically sensitive option we considered was the virus escaping the laboratory,” writes the Australian scientist. – We came to the conclusion that it is very unlikely.
On what basis?
The expert commission visited the Wuhan Institute of Virology. – We talked with local scientists. We heard that scientists’ blood samples that are routinely collected and stored were tested for infection. No evidence of anti-coronavirus antibodies was found. We also looked at their biosafety audits. No evidence – writes prof. Dwyer.
Specialists also looked at the pathogen closest to SARS-CoV-2 that Chinese scientists were working on, namely the RaTG13 virus (it was detected in caves in southern China). All the scientists had was the genetic sequence of this virus. They failed to breed it, the researcher reports. Although viruses are fleeing laboratories, this is rare. So we came to the conclusion that it is extremely unlikely that it will happen in Wuhan – he emphasizes.
- More in the article: WHO experts study a laboratory in Wuhan
Ending his account, Dominic Dwyer notes that the mission in China described was only phase one. – We are to publish an official report in the coming weeks – he informs. Scientists will also examine evidence that the virus has been circulating around Europe earlier, for example in early 2019. – In the region, specialists will continue to test animals (including wild ones) for signs of the virus. We will continue to learn from our experiences to improve the way we research the next pandemic, she emphasizes.
In the end, he shares a less optimistic conclusion: “Long-term effects, both physical and mental, will be felt in Wuhan and elsewhere in the world for decades to come.”
You may be interested in:
- Where did SARS-CoV-2 come from? A surprising discovery in laboratory freezers
- Why are some strains of the coronavirus more contagious than others?
- The four chronic diseases that are most dangerous in COVID-19
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