China scientists find new swine flu strain that capable of triggering pandemic
WASHINGTON: Researchers in China have discovered a new type of swine flu that is capable of triggering a pandemic, according to a study published on Monday in the US science journal PNAS.
Named G4, it is genetically descended from the H1N1 strain that caused a pandemic in 2009.
It possesses "all the essential hallmarks of being highly adapted to infect humans", say the authors, scientists at Chinese universities and China's Centre for Disease Control and Prevention.
From 2011 to 2018, researchers took 30,000 nasal swabs from pigs in slaughterhouses in 10 Chinese provinces and in a veterinary hospital, allowing them to isolate 179 swine flu viruses.
Most were of a new kind that has been dominant among pigs since 2016.
The researchers then carried out various experiments including on ferrets, which are widely used in flu studies because they experience similar symptoms to humans - principally fever, coughing and sneezing.
G4 was observed to be highly infectious, replicating in human cells and causing more serious symptoms in ferrets than other viruses.
Tests also showed that any immunity humans gain from exposure to seasonal flu does not provide protection from G4.
According to blood tests that showed up antibodies created by exposure to the virus, 10.4 per cent of swine workers had already been infected.
The tests showed that as many as 4.4 per cent of the general population also appeared to have been exposed.
The virus has therefore already passed from animals to humans, but there is no evidence yet that it can be passed from human to human - the scientists' main worry.
The World Health Organisation (WHO) will "read carefully" the Chinese study, a spokesman said yesterday, saying the findings underscored the importance of influenza surveillance during the Covid-19 pandemic.
"We will read carefully the paper to understand what is new," the WHO's Christian Lindmeier told a Geneva briefing, saying it was important to collaborate on findings and keep tabs on animal populations.
"It also highlights we cannot let our guard down on influenza and need to be vigilant and continue surveillance even in the coronavirus pandemic," he added. - AFP, REUTERS