Researchers in China have uncovered a new form of swine flu that could cause a pandemic, according to a report in the US science journal PNAS.
The flu, named G4, it is genetically derived from the H1N1 strain that caused a pandemic in 2009. It possesses “all the essential hallmarks of being highly adapted to infect humans” the authors, scientists at Chinese universities and the Chinese Center for Disease Control. and Prevention said in a study published on Monday.
Between 2011 and 2018, researchers took 30,000 nasal swabs from pigs in slaughterhouses in 10 Chinese provinces and in veterinary hospitals, allowing 179 swine flu viruses to be isolated.
The majority were of a new kind, which has been dominant among pigs since 2016.
Researchers then performed a number of experiments – including ferrets, which are commonly used in flu studies because they encounter symptoms identical to humans.
G4 has been shown to be highly contagious, replicating in human cells and causing more severe symptoms in ferrets than other viruses.
Tests have also shown that any human immunity benefit from seasonal flu exposure does not offer protection against G4.
More than one in 10 pig employees had already been contaminated according to antibody blood tests, which indicated susceptibility to the virus.
The studies also found that as many as 4.4% of the general population already seemed to have been exposed.
As a consequence, the virus has already spread from animals to humans, but there is no proof yet that it can be transmitted from human to human – the main concern of scientists.
“It is of concern that human infection with the G4 virus will further adapt to humans and increase the likelihood of a human pandemic,” the researchers wrote.
Zoonotic infection is caused by a pathogen that has transferred from a non-human species to a human being.