Chinese researchers warn of new virus in pigs

A new flu virus found in Chinese pigs has become more infectious to humans, according to a study.

It needs to be watched closely in case it becomes a potential "pandemic virus" -- although experts say there is no imminent threat.

The team of Chinese researchers looked at influenza viruses found in pigs from 2011 to 2018. They found a "G4" strain of H1N1 that has quote "all the essential hallmarks of a candidate pandemic virus."

Pig farm workers also showed elevated levels of the virus in their blood, according to the paper, published in a U.S. medical journal.

It added 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.

But while it is capable of infecting humans, there is no imminent risk of a new pandemic, according Carl Bergstrom, a biologist at the University of Washington.

He tweeted after the paper’s publication saying: "There's no evidence that G4 is circulating in humans, despite five years of extensive exposure...that's the key context to keep in mind."

The new virus identified in the study is a recombination of the 2009 H1N1 variant and a once prevalent strain found in pigs.

The coronavirus that caused the COVID-19 pandemic is believed to have originated in horseshoe bats in China and could have spread to humans via a seafood market in Wuhan, where the virus was first identified.

This study says pigs are considered important "mixing vessels" for the generation of pandemic influenza viruses and called for "systematic surveillance" of the problem.