Virus linked to COVID-19 had travelled over 2,700kms before it was detected in Wuhan

A study into the origins of COVID-19 has suggested that the virus spread through wildlife trade and did not transfer directly from bats to humans. Researchers pointed out that this is similar to what happened with the SARS outbreak in 2002. The study was conducted by researchers at the University of California, San Diego School of Medicine and published in the journal Cell on May 7, 2025.

According to the authors, the precursor to the virus SARS-CoV-2 had already travelled over 2,700 kilometres before it was detected in Wuhan, China. They state in the paper that the virus originated in bats from western China or northern Laos and spread extremely quickly. Such a speedy spread of the virus was not possible through a natural process, that is, dispersal from its primary host, the horseshoe bat.

Also Read: 'House of horror': Children aged 8 and 10, prisoned by parents since Covid, rescued

"We show that the original SARS-CoV-1 was circulating in Western China -- just one to two years before the emergence of SARS in Guangdong Province, South Central China, and SARS-CoV-2 in Western China or Northern Laos -- just five to seven years before the emergence of COVID-19 in Wuhan," said study author Jonathan Pekar, a postdoctoral researcher at the University of Edinburgh.

The speed of the spread of the virus prompted the authors to conclude that a "zoonotic spillover" happened, that is, it leapt from animals to humans, thwarting theories of a lab origin.

"The current study provides the strongest evidence to date that SARS-CoV-2 made it to humans in a similar manner,” the scientists stated.

The authors wrote that horseshoe bats are the main hosts of sarbecoviruses. While the virus does not harm the bats, they can prove deadly when they make an interspecies jump to humans. 

Also Read: China accuses US of being Covid-19 ground zero in fiery white paper, claims America 'tried to shift the blame'

The researchers state that viruses similar to SARS-CoV-2 have previously been found in palm civets and raccoon dogs in southern China. Michael Worobey, professor of ecology and evolutionary biology at the University of Arizona, “For more than two decades, the scientific community has concluded that the live-wildlife trade was how those hundreds of miles were covered. We’re seeing exactly the same pattern with SARS-CoV-2."

The authors further point out that sarbecoviruses similar to SARS-CoV-1, have been around in western China and Southeast Asia for over 1,000 years. But they travelled around only as much as the horseshoe bat travelled. 

The study also disputes the lab-origin theory, stating that while "there was a concern that the distance between Wuhan and the bat virus reservoir was too extreme for a zoonotic origin," it had happened before.

"This paper shows that it isn't unusual and is, in fact, extremely similar to the emergence of SARS-CoV-1 in 2002," co-senior author Joel Wertheim said.