Study finds 18 high-risk mammalian viruses in wildlife sold in Chinese markets

BEIJING • Wildlife species sold in wet markets in China were linked to the emergence of severe acute respiratory syndrome, or Sars, and Covid-19. Now a comprehensive survey of viral pathogens has found that they harbour a range of diseases threatening humans and other animals.

A study of more than a dozen species of game animals traded, sold and commonly consumed as exotic food in China has identified 71 mammalian viruses, including 18 deemed "potentially high-risk" to people and domestic animals.

Civets, the cat-like carnivores implicated in the spread of the Sars virus in markets in southern China almost 20 years ago, carried the most worrisome microbes, according to the research released on Friday.

Although the study's authors in China, the United States, Belgium and Australia did not find anything resembling Sars-CoV-2, the coronavirus that causes Covid-19, they showed that strains carried by bats are transmitted across the species barrier to infect other animals in spillover events that risk seeding dangerous outbreaks.

They also found that game animals were infected with viruses previously thought to exist only in people.

"This study highlights exactly why the wildlife trade and live animal markets are a pandemic accident waiting to happen," said co-author Edward Holmes, an evolutionary biologist at the University of Sydney, in an e-mail.

"This paper also shows that humans regularly transmit their viruses to other animals. There's clearly two-way virus traffic."

Among dozens of mammalian viruses identified over the past five years, 45 had not previously been described.

Among notable virus findings, the scientists identified for the first time the presence of hepatitis E virus and the H9N2 strain of influenza in badgers and civets.

That particular avian flu virus is now the most prevalent strain in chickens and ducks, and has led to numerous infections in people in China, the authors said.

The research was supported by the National Key Research and Development Programme of China and others.

The 40-page manuscript was released on bioRxiv, an open-access pre-print repository, ahead of peer review and publication.

Scientists have yet to determine the origins of Sars-CoV-2. The debate has coalesced around two competing ideas: a laboratory escape or a spillover from animals.

The wildlife market in China was worth an estimated 520 billion yuan (S$110 billion) in 2016. China banned the trade after Covid-19 emerged, and the government has subsequently prohibited human consumption of terrestrial wild animals.

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