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Coronavirus pandemic
ChinaScience

Coronavirus: pathogen could have been spreading in humans for years, study says

  • Virus may have jumped from animal to humans long before the first detection in Wuhan, according to research by an international team of scientists
  • Findings significantly reduce the possibility of the virus having a laboratory origin, director of the US National Institute of Health says

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An international team of scientists say the coronavirus may have jumped from animal to humans long before the first detection in China. Photo: AP
Stephen Chen
The coronavirus that causes Covid-19 might have been quietly spreading among humans for years or even decades before the sudden outbreak that sparked a global health crisis, according to an investigation by some of the world’s top virus hunters.
Researchers from the United States, Britain and Australia looked at piles of data released by scientists around the world for clues about the virus’ evolutionary past, and found it might have made the jump from animal to humans long before the first detection in the central China city of Wuhan.

Though there could be other possibilities, the scientists said the coronavirus carried a unique mutation that was not found in suspected animal hosts, but was likely to occur during repeated, small-cluster infections in humans.

The study, conducted by Kristian Andersen from the Scripps Research Institute in California, Andrew Rambaut from the University of Edinburgh in Scotland, Ian Lipkin from Columbia University in New York, Edward Holmes from the University of Sydney, and Robert Garry from Tulane University in New Orleans, was published in the scientific journal Nature Medicine on March 17.

Dr Francis Collins, director of the US National Institute of Health, who was not involved in the research, said the study suggested a possible scenario in which the coronavirus crossed from animals into humans before it became capable of causing disease in people.

“Then, as a result of gradual evolutionary changes over years or perhaps decades, the virus eventually gained the ability to spread from human to human and cause serious, often life-threatening disease,” he said in an article published on the institute’s website on Thursday.

In December, doctors in Wuhan began noticing a surge in the number of people suffering from a mysterious pneumonia. Tests for flu and other pathogens returned negative. An unknown strain was isolated, and a team from the Wuhan Institute of Virology led by Shi Zhengli traced its origin to a bat virus found in a mountain cave close to the China-Myanmar border.
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