(CNN/Gray News) – Health experts are keeping a close eye on a new swine flu virus found that’s a lot like the one that circulated more than a decade ago.
The disease, which researchers are calling the G4 virus, is genetically descended from the H1N1 swine flu that caused a pandemic in 2009.
G4 now shows “all the essential hallmarks of a candidate pandemic virus,” according to the study, published in the scientific journal Proceedings of the National Academy of Sciences.
It appears the virus has been circulating in China’s pig population since 2016 with few instances of pig-to-human transmission.
The potential of human-to-human contagion has not been confirmed.
Angela Rasmussen, a virologist at Columbia University’s public health school, said there’s no immediate threat.
"Our understanding of what is a potential pandemic influenza strain is limited," she posted on Twitter. "Sure, this virus meets a lot of the basic criteria but it's not for sure going to cause a hypothetical 2020 flu pandemic, or even be a dominant strain in humans."
The World Health Organization said it’s closely monitoring new data as it emerges.
In 2009, the H1N1 swine flu pandemic killed an estimated 151,700 to 575,400 people globally. In the aftermath, authorities and scientists stepped up surveillance of pig populations to watch for viruses with “pandemic potential.”