A new study indicates that the spread of the COVID-19 virus (SARS-CoV-2) may have been driven by the wildlife trade, rather than claims of a lab leak.
In a study published in the science journal Cell, the researchers from UC San Diego’s School of Medicine studied the genomes of 250 coronaviruses to reconstruct how the pathogens evolved, potentially offering insights into how COVID-19 transmitted into people.
Researchers analysed the history of the virus and found that its rapid emergence in Wuhan, China, was inconsistent with the natural dispersal patterns of its primary host, the horseshoe bat. The finding indicates that the virus may have been transported via the wildlife trade, mirroring the transmission pathway of the 2002 SARS outbreak (caused by SARS-CoV-1).
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While the study doesn’t definitively prove that the virus was carried to the Wuhan wet market via wildlife trade, the researchers emphasise that the similarities between COVID-19 and previous pandemics are too significant to overlook.
The study found that sarbecoviruses related to SARS-CoV-1 and SARS-CoV-2 have circulated around Western China and Southeast Asia for millennia. During this time, they moved around the landscape at similar rates as their horseshoe bat hosts.
“At the outset of the COVID-19 pandemic, there was a concern that the distance between Wuhan and the bat virus reservoir was too extreme for a zoonotic origin,” said co-senior author Joel Wertheim, Ph.D., a professor of medicine at UC San Diego School of Medicine’s Division of Infectious Diseases and Global Public Health. “This paper shows that it isn’t unusual and is, in fact, extremely similar to the emergence of SARS-Cov-1 in 2002.”
“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 Jonathan E. Pekar, Ph.D., a 2023 graduate of the Bioinformatics and Systems Biology program at UC San Diego School of Medicine.
The origins of COVID-19 have been at the centre of worldwide debate. While the United States previously suggested that the virus may have accidentally escaped from a lab, Chinese officials have rejected the claim and instead accused America of politicising the pandemic.
