The microorganism is being called “G4” and is of particular concern because it combines characteristics of strains that infect birds and mammals.
Researchers at China Agricultural University in Beijing have discovered a new influenza virus with pandemic potential, according to a study published on Monday (29) in the scientific journal PNAS. The microorganism, found in pigs, has characteristics of different strains of viruses and “all the essential hallmarks of a candidate pandemic virus,” according to the article.
When multiple strains of influenza viruses infect the same pig, they can easily “exchange” genes with one another, a process known as “rearrangement” – and scientists believe that is what happened. The microorganism is a unique mixture of three strains: one similar to the strains found in European and Asian birds; the H1N1 strain that caused the 2009 pandemic; and a North American strain of H1N1 that has genes from avian, human and pig influenza viruses.
The microorganism, which is being called G4, is of particular concern because its core is similar to the avian flu virus, to which humans have no immunity, with parts of strains that infect mammals. According to the researchers, the inclusion of genes from the H1N1 virus that caused the 2009 pandemic increases the potential of the virus to “jump” between species.
“From the data presented, it appears that this is a swine influenza virus that is poised to emerge in humans,” said Edward Holmes, an evolutionary biologist at the University of Sydney in Australia, who was not involved in the study, in an interview with Science. “Clearly this situation needs to be monitored very closely.”
As the researchers explain, people who live in densely populated rural areas are especially vulnerable, as they have more direct contact with animals that carry these microorganisms. In addition, eating meat increases the chances of the virus jumping from one species to another.
According to the scientists, laboratory studies show that G4 was able to infect and replicate in common epithelial cells in the human airways. Additionally, the researchers found antibodies to the G4 strain in 4.4% of the 230 people studied in a household survey – and the rate was more than double among people who work directly with pigs.
“We need to be vigilant about other infectious disease threats even as COVID is going on,” said Martha Nelson, a biologist at the U.S. National Institutes of Health’s Fogarty International Center, who was not involved in the research. “Viruses have no interest in whether we’re already having another pandemic.”