By Jessica Nix and Gerry Smith | Bloomberg
US officials are investigating the appearance of a strain of bird flu identified in the US for the first time, a worrying sign that the virus is evolving in ways that could make it harder to contain.
Detected on a duck farm in Merced County, California, it’s the first confirmed case of H5N9 in poultry in the US, according to the website for the World Organization for Animal Health, a Paris-based group focused on animal diseases.
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The California case wasn’t announced by US health officials, as the Trump administration has paused government communications on health topics pending a political review. Scientists worry that could delay the release of essential information to the public, including about disease outbreaks.
“It is extremely unusual, and I believe it reflects the policy decision for everyone to go dark,” said Michael Kinch, a vaccine specialist who’s chief innovation officer at Stony Brook University. “It’s troubling because any sort of non-typical influenza is particularly problematic when it gains the ability to jump between species.”
New strains of bird flu are concerning as the disease has caused hundreds of deaths in people over the years, mainly via exposure to infected animals, and the US Department of Agriculture and state officials are investigating the case. A more common bird flu strain, H5N1, has recently been spreading in US farm animals, although severe cases in people have been rare.
H5N9 is a subtype of bird flu, and a version that appeared in China more than a decade ago was “highly pathogenic,” according to a 2015 academic paper by researchers in the country. The H5N9 version is thought to come from a genetic combination of other bird flu viruses, including H5N1.
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US officials are required to report diseases in animals to the World Organization for Animal Health, according to the USDA website. The US agency didn’t respond to requests for comment on why it didn’t report the case publicly.
Concerns about H5N1, which has been known and studied for more than a decade, have been rising since a death was linked to the virus in Louisiana earlier this month. H5N9 is a less researched viral strain. If it becomes widespread in humans, scientists would likely have to start from the beginning with developing vaccines and researching the virus, Kinch said.
“This the wrong time of year and the wrong virus to be messing around with,” Kinch said.
US health officials have been monitoring the H5N1 virus for genetic mutations that could make it more dangerous. For now, they say there’s no evidence of human-to-human spread and the risk to the general public remains low.
Still, the new case shows that H5N1 is starting to mix genetic material with other influenza viruses, “which is concerning,” said Peter Hotez, a vaccine expert and dean of the National School of Tropical Medicine at Baylor College of Medicine.
Richard Webby, a specialist in influenza at St. Jude Children’s Research Hospital in Memphis, said the new H5N9 case doesn’t itself appear to raise the risk to humans or animals. Still, he said, researchers need to look closely at the genetic sequence to see if any important changes have occurred.
“Anytime a flu virus mutates or evolves we can’t predict the end result of that,” Webby said.
–With assistance from Michael Hirtzer and Ilena Peng.
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