New swine flu found in China could trigger pandemic, scientists warn
A new strain of swine flu that can infect humans and has the potential to trigger a pandemic has been identified by Chinese researchers.
The so-called G4 virus emerged in recent years and is genetically descended from the H1N1 strain that led to a pandemic in 2009.
A study published in the US journal Proceedings of the National Academy of Sciences found that G4 has "all the essential hallmarks” of a pandemic virus and must be closely monitored.
The discovery is the result of a seven-year surveillance programme that ran from 2011 to 2018, during which time researchers from Chinese universities and the country's Centre for Disease Control and Prevention were able to isolate 179 swine flu viruses.
This was done by taking 30,000 nasal swabs from pigs in slaughterhouses in 10 Chinese provinces and in a veterinary hospital.
While some of the viruses only showed up once and were considered non-threatening, the G4 virus appeared in pigs year after year, with its presence increasing sharply after 2016.
Tests revealed that G4 has already infected humans in China's Hebei and Shandong provinces, which have large swine populations. Here, more than 10 percent of pig farm workers and 4.4 percent of the general population have tested positive for the virus.
While there is no evidence yet that G4 can spread from person to person, the study's authors fear a further mutation of the virus will allow humans to infect each other.
Existing flu vaccines do not appear to protect against G4. People would have little or no immunity from the virus, scientists say, given that it is new.
G4 is still on the rise in China's swine population, with researchers warning it is potentially deadly to humans because it can grow and multiply in the cells that line our airways.
The World Health Organization says it is looking into the Chinese study, and stressed the importance for science to collaborate their findings and to keep tabs on animal populations.
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"It also highlights we cannot let our guard down on influenza and need to be vigilant and continue surveillance even in the coronavirus pandemic," a spokesman said Tuesday.
Scientists are calling for swift measures to control the G4 virus in pigs, and for the swine industry workers to be closely monitored.
China's Foreign Ministry on Tuesday said the country would “take all necessary measures to prevent the spread and outbreak of any virus”.