Swine Flu Virus Found to Fuel Future Pandemic
Researchers have discovered a strain of swine flu virus in China with all the characteristics capable of causing a future pandemic, according to a study published Monday in the American scientific journal PNAS.
The viruses are called G4 and are genetically descended from the H1N1 strain that caused a pandemic in 2009: they “have all the essential traits showing high adaptability to infect humans”, write the authors, scientists from Chinese universities and the Center for Prevention and Control of Chinese Diseases.
The work presented is voluminous: from 2011 to 2018, 30,000 nasal swabs were taken from pigs in slaughterhouses in 10 Chinese provinces and in a veterinary hospital, making it possible to isolate 179 swine flu viruses. The majority were of the new variety, which has become dominant in pigs since 2016.
The researchers then carried out various experiments in the laboratory and on ferrets, animals widely used in influenza research, because their symptoms are comparable to those of humans: they have a fever, cough and sneeze.
They observed that G4 viruses were more infectious, replicated in human cells, and caused ferrets to experience more severe symptoms than other strains.
In addition, according to in vitro tests, immunity obtained after contact with human seasonal influenza viruses does not protect against G4.
The other bad news is that workers and pig workers were relatively likely to have been infected, 10.4%, according to blood tests that looked for antibodies to the virus. 4.4% of the general population also appeared to be infected.
The virus has therefore already spread to humans, scientists say, but there is no evidence that it can be transmitted from human to human. This is their fear today.
“Pandemics occur when influenza A viruses with a new HA surface antigen become able to spread from human to human,” the researchers conclude. “The concern is that infections of humans with the G4 virus will not lead to human adaptation and increase the risk of a human pandemic.”
There is an urgent need, they say, to put in place surveillance of populations working in contact with pigs.
“The work is a salutary reminder that we are constantly running the risk of the emergence of zoonotic pathogens, and that farm animals, with which humans are more in contact than with wild animals, are the source of pandemic viruses important, “said James Wood, head of the department of veterinary medicine at the University of Cambridge.
Swine Flu Virus Found to Fuel Future Pandemic - /10
Researchers have discovered a strain of swine flu virus in China with all the characteristics capable of causing a future pandemic...