
Named G4, it is genetically descended from the
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.


G4 was observed to be highly infectious, replicating in human cells and causing more serious symptoms in ferrets than other viruses.
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 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.
“It is of concern that human infection of G4 virus will further human adaptation and increase the risk of a human pandemic,” the researchers wrote.


“The work comes as a salutary reminder that we are constantly at risk of new emergence of zoonotic pathogens and that farmed animals, with which humans have greater contact than with wildlife, may act as the source for important pandemic viruses,” said James Wood, head of the department of veterinary medicine at Cambridge University.
A zoonotic infection is caused by a pathogen that has jumped from a non-human animal into a human.-South China Morning Post