The team of researchers sequenced samples from 461 animals from fur farms, mostly in north eastern China. All had died after suffering from disease. The scientists identified 125 different virus species, including 36 new pathogens.
Of the viruses detected, 39 were deemed to have high spillover potential because they were “generalists” spotted in a diversity of animals.
The team also detected seven coronaviruses, with the original hosts traced to rodents, rabbits and canines. Though none were closely related to Sars-Cov-2, a concerning new bat coronavirus was discovered. Called HKU5, it was found in the lungs and intestines of mink which had died from a pneumonia outbreak on a fur farm.
HKU5 ‘is a red flag’
“The question always is, can we work out what sorts of viruses we should worry most about, which are most likely to emerge [in humans]? It’s very hard to say, but if viruses are able to jump big evolutionary distances, it suggests they can replicate in different cell types. That is a risk,” said Dr Holmes.
“HKU5 needs to go on a watchlist immediately. It is absolutely a red flag,” he added, calling for more rigorous surveillance of fur farms inside China and across the globe.
Prof Linfa Wang, director of the Emerging Infectious Diseases Research Programme at Singapore’s Duke-NUS Medical School, who was not involved in the study, said he agreed that HKU5 was a red flag, but that “we need more data from lab-based infection studies to corroborate this”.
Scientists have long been concerned that mink farms could provide fertile ground for viruses to mutate, as the animals are susceptible to many of the same viruses as humans.
In autumn 2020, Denmark culled its entire population of farmed mink – some five million animals – after a Covid-19 jumped from humans to mink, mutated, and then re-infected humans with a new strain. There was also alarm in Spain in 2022, when avian influenza was reported in a mink farm in the country’s north-west.
