A pig infected with bird flu in Oregon has raised concerns about the virus’s potential to threaten humans, but the current risk to the public remains low.

According to the U.S. Department of Agriculture, the pig that tested positive lived on a farm in central Oregon, where different animals share water and are housed together. This is the first time the virus has been detected in American pigs.

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The farm was quarantined and all five pigs were euthanized so that further testing could be carried out. It is not a commercial farm, and U.S. agriculture officials have said there are no concerns about the security of the nation’s pork supply.

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But the discovery of bird flu in a pig raises concerns that the virus is a stepping stone to becoming a bigger threat to humans, said Jennifer Nuzzo, a pandemic researcher at Brown University.

FILE – Pigs in a pasture (Photo by D. Logan/ClassicStock/Getty Images)

Pigs can be infected with several types of flu, and animals may play a role in making avian viruses better adapted to humans, she explained. The 2009 H1N1 flu pandemic had swine origins, Nuzzo noted.

The USDA conducted genetic testing on the farm’s poultry and found no mutations suggesting the virus is gaining an increased ability to spread to humans. This indicates that the current risk to the public remains low, officials said.

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Another strain of the avian flu virus has been reported in pigs outside the United States in the past, and it has not sparked a human pandemic.

The Oregon swine infection “is remarkable, but does it change the threat level calculus? No, it doesn’t,” said Troy Sutton, a Penn State researcher who studies viruses influenza in animals. If the virus starts to spread more widely among pigs and human infections follow, “then we will be more worried.”

So far this year, nearly 40 human cases have been reported – in California, Colorado, Washington, Michigan, Texas and Missouri – with mostly mild symptoms, including redness of the eyes, reported. All but one person had contact with infected animals.