New virus in China with ‘pandemic threat’

Professor James Wood, head of the Department of Veterinary Medicine at the University of Cambridge, said the work ‘comes as a salutary reminder’ that we are constantly at risk of new emergence of pathogens. The farmed animals, with which humans have greater contact than with wildlife, may act as the source for important pandemic viruses

A flu virus strain, identified among pigs in China, is jumping species to infect swine industry workers, according to a study which says the pathogen has "all the essential hallmarks of a candidate pandemic virus," however experts say there is no imminent threat of another global outbreak.

The study, published in the journal PNAS, is based on a surveillance of pigs in China from 2011 to 2018, and found that the influenza virus strain, with genetic material termed as G4 genotype, has become predominant in swine populations since 2016.

According to the scientists, including those from the Chinese Center for Disease Control and Prevention, these G4 viruses bind to receptor molecules in human cells, and can replicate in the outer layer of the respiratory system.

Eric FeiglDing, an epidemiologist at Harvard University in the US, who is unrelated to the study, tweeted that the virus is just in pigs for now. "Only two cases. And it's an older 2016 origin virus. No human to human yet. 10 per cent of swine farmers have antibodies. No real flashing red light evidence yet," he mentioned on the micro-blogging platfrom. Despite five years of extensive exposure of humans to the virus, there's no evidence of it spreading from one person to another, said Carl T. Bergstrom, a biologist at the University of Washington in the US, who is unrelated to the study.

"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," Bergstrom tweeted.

However, he said it is important to monitor the emerging situation.

"What the paper does do is something important for the epidemiological community: it points to a virus that we need to be keeping a careful eye on," Bergstrom said. "Screening will be important, particularly if clusters of illness emerge in swine workers," he said on Twitter.