Pigs in their stable on a farm on the outskirts of Chengdu in southwest China's Sichuan Province on August 2, 2005.
Peter Parks | AFP | Getty Images
Scientists have identified a new strain of flu that is transmitted by pigs in China and that has the potential to become a pandemic.
The new strain descends from the type of flu known as "swine flu", which occurred in 2009 and caused the first global flu pandemic in 40 years.
The scientists published their peer-reviewed results on Monday in the National Academy of Sciences' science journal Proceedings. They said that the new flu strain, which they called "G4 EA H1N1", is a variation of swine flu and contains the genotype "G4", which has been prevalent in pig populations since 2016.
As with swine flu, the new strain was found to have "all of the essential characteristics of a candidate for a pandemic virus".
The researchers, who examined flu viruses in pig populations between 2011 and 2018, found that around 10% of workers in the pig industry tested in China were already exposed to the virus, which they described as "worrying". This rate increased among younger workers ages 18 to 35, "indicating that the prevalent G4 EA H1N1 virus has become more infectious in humans."
"Such infectivity significantly increases the possibilities for virus adaptation in humans and raises concerns about the possible development of pandemic viruses," said the researchers, who work at several Chinese universities and at the country's disease control and prevention center.
They recommended close monitoring of pig populations – and everyone who works with them.
"The fight against the prevalent G4 EA H1N1 virus in pigs and the close monitoring of human populations, especially workers in the pig industry, should be implemented urgently," they write.
"Pigs are intermediate hosts for the development of the pandemic influenza virus. Therefore, the systematic monitoring of influenza viruses in pigs is a key measure to warn in advance of the next pandemic influenza."
While "swine flu", which first appeared in Mexico in 2009, is now considered one of the various seasonal flu viruses and is contained in annual flu vaccines, the scientists offer that existing immunity does not protect the population against G4 viruses. "
However, they wanted to emphasize that the virus is not an immediate problem.
Professor Kin-Chow Chang, one of the researchers involved in the study and working at Nottingham University in the UK, told the BBC: "While this new virus is not an immediate problem … we should not ignore it."
"Right now we are rightly distracted from the corona virus. But we must not lose sight of potentially dangerous new viruses."
Current flu vaccines do not appear to protect against it, although they could possibly be adjusted if necessary, the BBC reported. To carry out their research, scientists conducted swine flu surveillance in 10 Chinese provinces between January 2011 and April 2018, collecting almost 30,000 nasal swabs from slaughtered pigs from slaughterhouses and over 1,000 nasal swabs or lung tissue from breeding pigs with signs of respiratory disease.