But Dr. Angela Rasmussen, a virologist at Columbia University’s school of public health, warned the public not to “go crazy”.
Chinese researchers based in several institutions, including Shandong Agricultural University and the Chinese National Influenza Center, discovered the G4 virus during a pig surveillance program. From 2011 to 2018, they collected over 30,000 swab nasal swab samples from slaughterhouses and veterinary teaching hospitals in 10 Chinese provinces.
From these samples, the researchers identified 179 swine flu viruses, but not all of them raised concern. Some showed up only one year in seven of the program, or eventually dropped to non-threatening levels.
But the G4 virus continued to manifest itself in pigs year after year – and even showed a sharp increase in the pig population after 2016.
Further tests have shown that G4 can infect humans by binding to our cells and receptors, and can rapidly replicate within our airway cells. And although G4 holds H1N1 genes, people who have received seasonal flu shots will have no immunity.
G4 already appears to have infected humans in China. In the provinces of Hebei and Shandong, both places with a high number of pigs, over 10% of the pig workers in pig farms and 4.4% of the general population proved positive in a survey from 2016 to 2018.
There is still no evidence that G4 can spread from person to person – perhaps the most promising sign so far, said Carl Bergstrom, professor of biology at the University of Washington.
However, the researchers warn in the document that the virus was on the rise among pig populations and that they could “pose a serious threat to human health” if not carefully monitored. Transmission of the virus from pig to humans could “lead to serious infections and even death,” said the study, which required greater control over the spread of the virus within pig populations.
Surveillance and discovery
After 2009, the H1N1 virus in humans has spread to pigs around the world and genes have mixed in new combinations, creating new viruses such as G4.
“Pig farming is a huge industry in China and pigs can be important hosts from which new flu viruses can emerge,” said James Wood, head of veterinary medicine at the University of Cambridge. He added that the study was a “healthy reminder that we are constantly at risk of new emergencies of zoonotic pathogens and that farm animals, with which humans have more contact than wildlife, can act as a source of important pandemic viruses. “
To reduce the risk of a human pandemic, Chinese farmers and authorities need to monitor the spread of the virus among pigs and closely monitor people who work with animals, the team said.
The central Chinese city of Wuhan is zero for the coronavirus novel, which emerged in December last year and started to spread internationally in January. The outbreak prompted China to impose strict national blockades, closing local and provincial borders and ordering residents to stay home.
The country started reopening in March after having largely contained the virus, but new outbreaks and local broadcasts in recent weeks have seen some cities go back to a blockade.