A new flu virus found in Chinese pigs has become more infectious to humans and needs to be watched closely in case it becomes a potential “pandemic virus,” according to a new study published in the journal Proceedings of the National Academy of Sciences (PNAS).
A team of Chinese researchers looked at influenza viruses found in pigs from 2011 to 2018 and found a “G4” strain of H1N1 that has “all the essential hallmarks of a candidate pandemic virus,” according to the paper, first reported by Reuters.
“Pigs are considered as important hosts or ‘mixing vessels’ for the generation of pandemic influenza viruses,” the study’s abstract pointed out. “Systematic surveillance of influenza viruses in pigs is essential for early warning and preparedness for the next potential pandemic.”
Pig farm workers also showed elevated levels of the virus in their blood, the authors said, adding that “close monitoring in human populations, especially the workers in the swine industry, should be urgently implemented.”
The study highlights the risks of viruses crossing the species barrier into humans, especially in densely populated regions in China, where millions live in close proximity to farms, breeding facilities, slaughterhouses and wet markets.
The coronavirus that caused the worldwide COVID-19 pandemic is believed to have originated in horseshoe bats in southwest China, and could have spread to humans via a seafood market in Wuhan, where the virus was first identified.
The new virus identified in the study is a recombination of the 2009 H1N1 variant and a once prevalent strain found in pigs.
But while it is capable of infecting humans, there is no imminent risk of a new pandemic, said Carl Bergstrom, a biologist at the University of Washington, Reuters reported.
“There’s no evidence that G4 is circulating in humans, despite five years of extensive exposure,” Bergstrom said on Twitter after the paper’s publication. “That’s the key context to keep in mind.”