Ancestral type of COVID-19 virus mainly found in the US: study
By Gao Lei and Liu Caiyu Source:Global Times Published: 2020/4/11 14:47:14
File Photo of COVID-19
Recent research conducted into the genetic network analysis of the COVID-19 pandemic, done jointly by British and German experts, testified the variant of novel coronavirus that is closest to that discovered in bats was actually found mainly among cases from the US, rather than in Wuhan, Central China's Hubei Province.
To explain the pandemic origins, experts from the University of Cambridge and their peers from Germany analyzed 160 virus genomes that were extracted from human patients around the world and they found the coronavirus mutated into three distinct strains.
They found that most cases carried type A virus - the ancestral type of virus, which is bat coronavirus, with 96 percent sequence similarity to the human virus - were largely seen in patients from the US and Australia.
Once type A had been detected in Wuhan. The virus infected five individuals from Wuhan and four patients from South China's Guangdong Province. But most cases from the Chinese mainland and East Asian regions do not carry type A virus but carried the type B virus, which is a variant of type A, the study found.
Instead, patients carrying the ancestral type of virus (type A) were largely seen coming from the US and Australia, such American patients had a residence history in Wuhan, the study found.
As for type C, it is a variant of type B, which is commonly seen in European countries such as France, Italy and Sweden and also evident in Singapore and South Korea as well as China's Hong Kong and the island of Taiwan , the study found.
In reply to the question why the ancestral type of virus was not commonly seen in China and particularly in Wuhan, but instead the mutated type B virus, geneticist Peter Forster from the University of Cambridge, lead author of the study, told the Global Times that "type A isn't fitting quite well with most locals' immune systems in Wuhan" but has "become adapted to American and Australian immune systems."
The prevalence of variant type B virus in Wuhan may also result from a "founder effect," Forster said.
The study was published in the journal, Proceedings of the National Academy of Sciences (PNAS).
To trace the pandemic origins, apart from the paper that was published on the PNAS, Forster told the Global Times that they also finished an analysis of 1,001 genomes, which is still unpublished.
Forster said he understands the topic of the viral origin is a "hot potato" after the political dispute between China and the US, but neither the PNAS paper nor the unpublished paper could offer a clear explanation for it.
But their study has evidence that the virus mutation rate is significantly faster outside China and the spread of the disease among humans likely occurred between September 13, 2019 to December 7, 2019.
https://www.globaltimes.cn/content/1185291.shtml
Science cannot lie
Deadly coronavirus comes in three variants, researchers find
Types A, B and C are all derived from the pathogen first found in bats but have evolved in different ways, according to a report by British and German geneticists
Findings show the virus has become well adapted to human transmission and mutates as it spreads, Chinese epidemiologist says
Published: 9:00pm, 11 Apr, 2020
Geneticists from Britain and Germany have mapped the evolutionary path of the coronavirus that causes Covid-19 and determined there are currently three versions of it spreading around the world
The discovery of how the variants were formed and then spread could help scientists to identify its source and explain why it is so contagious.
The researchers analysed the first 160 complete viral genomes sequenced from human patients between December 24 and March 4, then reconstructed the early evolutionary pathway of Covid-19 in humans through its mutations.
“There are too many rapid mutations to neatly trace a Covid-19 family tree. We used a mathematical network algorithm to visualise all the plausible trees simultaneously,” said Peter Forster, a geneticist at University of Cambridge and lead author of the study.
“These techniques are mostly known for mapping the movements of prehistoric human populations through DNA. We think this is one of the first times they have been used to trace the infection routes of a coronavirus like Covid-19,” he said in a report about the study on the university’s website.
The team labelled the three variants A, B and C.
Type A was closest to the coronavirus discovered in bats and although found in wuhan – the central China city that was the epicentre of the initial outbreak – was not the primary type there, they said.
Type A was found in Americans who had lived in Wuhan, and in many other patients diagnosed in the United States and Australia.
The most common variant found in Wuhan was type B, the study said, though this appeared not to have travelled much beyond East Asia before mutating, which the researchers said was probably due to some form of resistance to it outside that region.
Finally, type C was the variant found most often in Europe based on cases in France, Italy, Sweden and England. It had not been detected in any patients in mainland China, though had been found in samples from Singapore, Hong Kong and South Korea, the study said.
The researchers concluded that variant A was the root of the outbreak as it was most closely related to the virus found in bats and pangolins. Type B was derived from A, separated by two mutations, while type C was the “daughter” of variant B.
“The Wuhan B-type virus could be immunologically or environmentally adapted to a large section of the East Asian population,” Forster said.
“It may need to mutate to overcome resistance outside East Asia. We seem to see a slower mutation rate in East Asia than elsewhere, in this initial phase.”
The research also documented how people’s movements had helped the spread of the virus
For example, the study suggested that one of the earliest introductions of the virus to Italy – found in a Mexican traveller who was diagnosed on February 28 – came via the first documented German infection – a person who worked for a company in Munich – on January 27.
The German contracted the infection from a Chinese colleague in Shanghai, who had recently been visited by her parents from Wuhan.
The researchers documented 10 mutations in the viral journey from Wuhan to Mexico.
“Because we have reconstructed the "family tree" (the evolutionary history) of the human virus, we can use this tree to trace infection routes from one human to the next, and thus have a statistical tool to suppress future infection when the virus tries to return,” Forster said.
He added that researchers can better determine when the outbreak started with the data.
“I hope this improved knowledge of the origin and spread will enable more precise computer simulations to predict which measures will be most effective,” he said.
Lu Jiahai, an epidemiologist at Sun Yat-sen University Guangzhou, the capital of Guangdong, said the study had provided a preliminary analysis of genomics and molecular variation.
“The virus mutates during spreading and has become more adapted to transmission among humans in different populations from different countries,” he said.
But as the variants were related to each other, tracking mutations within different groups could help to determine the origin of the virus, he said.
“This research indicates that the spread of the virus is increasingly adapted to different populations and therefore the pandemic needs to be taken seriously,” Lu said.
“People need to pay more attention to prevention and control … the virus may coexist with humans for a long time.”
https://www.scmp.com/news/china/sci...navirus-comes-three-variants-researchers-find
I wonder why many holy western media not say anything about this one?
Because it reveal the ugly truth
