Genetic testing of samples from more than 7,500 people infected with COVID-19 suggests that the new coronavirus is spreading rapidly around the world after it appeared in China sometime between October and December last year, scientists said on Wednesday.
Scientists from the University College London Genetics Institute found nearly 200 recurrent genetic mutations in the new coronavirus – SARS-CoV-2 – that, according to UCL researchers, showed how it adapts to its human hosts as it spreads.
"Phylogenetic estimates show that the COVID-2 pandemic started sometime between October 6, 2019 and December 11, 2019, which is the time of the economic leap in humans," wrote the research team led by Francois Balloux in a study published in Infection, Genetics and Evolution.
Balloux said that the analysis also found that the virus mutates and mutates, as is normally the case with viruses, and that much of the global genetic diversity of the virus that causes COVID-19 is found in all of the most affected countries has been.
This suggests that SARS-CoV-2 has been widely transmitted worldwide from the beginning of the epidemic, he said.
"All viruses mutate naturally. Mutations in themselves are not a bad thing, and there is no evidence that SARS-CoV-2 mutates faster or slower than expected," he said. "So far we have not been able to say whether SARS-CoV-2 will be more or less deadly and contagious."
In a second study, also published on Wednesday, scientists from the University of Glasgow in the UK, who also analyzed SARS-CoV-2 virus samples, said their results showed that previous work, indicating that there were two different strains, were inaccurate.
CIRCULATE ONLY A VIRUS TYPE
A preliminary study by Chinese scientists in March had revealed that two strains of the new coronavirus may have caused infections, more "aggressive" than the others.
However, the Glasgow team published its analysis in Virus Evolution magazine, saying that only one type of virus was in circulation.
According to a Reuters balance sheet, more than 3.71 million people worldwide are infected with the novel corona virus, and 258,186 have died.
Cases have been reported in more than 210 countries and areas since they were first identified in China in December 2019.
The genetic studies offer "fascinating" insights into the evolution of the virus and emphasize that it is "a moving target with an unknown evolutionary target," said Jonathan Stoye, head of the Virology Department at the British Crick Institute.
"All of the evidence is entirely in line with an origin late last year and there is no reason to question it in any way," said Stoye.
A study by French scientists published earlier this week found that a man in France was infected with COVID-19 on December 27, almost a month before the local authorities confirmed the first cases.
The World Health Organization said the French case was "not surprising" and asked countries to investigate other early suspicious cases.
The Balloux team examined the genome of more than 7,500 viruses from infected patients around the world. Their results add to a growing body of evidence that SARS-CoV-2 viruses have a common ancestor by the end of 2019, suggesting that the virus jumped into humans from a previous animal farmer.
The UCL researchers also found nearly 200 small genetic changes or mutations in the coronavirus genomes they analyzed – results that Balloux said were helpful pointers for researchers who wanted to develop drugs and vaccines.
(Except for the headline, this story was not edited by NDTV staff and published from a syndicated feed.)