New swine flu found in pigs in China with ‘human pandemic potential’
A new strain of swine flu with “pandemic potential” has been identified by scientists in China, according to a newly-released study.
Researchers from the China Agricultural University, the Chinese Centre for Disease Control and Prevention and the University of Nottingham, in the UK, revealed that influenza virus surveillance on pigs between 2011 and 2018 has led to the discovery of a new H1N1 strain they have named G4.
“G4 viruses have all the essential hallmarks of a candidate pandemic virus,” the study, released on Monday in the PNAS journal, states.
“Of concern is that swine workers show elevated seroprevalence for G4 virus. Controlling the prevailing G4 EA H1N1 viruses in pigs and close monitoring in human populations, especially the workers in swine industry, should be urgently implemented,” it adds.
“Such infectivity greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses,” researchers said.
They found the new strain has been predominant among pigs since 2016.
One in 10 pig farm workers tested also showed elevated levels of the virus in their blood, particularly those aged 18 to 35 years old.
They also found that human influenza vaccine strains do not provide immunity against G4 viruses.
“Close monitoring in human populations, especially the workers in the swine industry, should be urgently implemented.”
But while it is capable of infecting humans, there is no imminent threat of a new pandemic, said Carl Bergstrom, a biologist at the University of Washington.
“There’s no evidence that G4 is circulating in humans, despite five years of extensive exposure,” he said on Twitter after the paper’s publication.
“That’s the key context to keep in mind.”
The study was published in the US journal, Proceedings of the National Academy of Sciences (PNAS).
The 2009 outbreak of a new strain of swine flu killed between 157,000 and 575,000 people worldwide, according to the US Centers for Disease Control and Prevention (CDC).
Eighty per cent of the fatalities were estimated to have occurred in people younger than 65 years of age. Nearly one-third of people over the age of 60 had antibodies against the virus, “likely from exposure to an older H1N1 virus earlier in their lives,” the CDC said.
A vaccine was quickly developed and the pandemic was declared over by the World Health Organization in August 2010.