Writing in the journal mBio, researchers from Columbia University, NOAA and other institutions say they found harbor seals infected with a new strain of H3N8 avian influenza.
Most of the fatalities were noted among seal pups less than 6 months old, which suffered severe pneumonia and skin lesions.
Columbia researcher Simon Anthony said the virus developed the ability to attack the respiratory tracts of the marine mammals, and may have also become more virulent and easier to catch.
Since the H1N1 and H5N1 strains of bird flu have infected humans before, this new seal outbreak could pose a threat to public health, the scientists warn.
“It’s important to realize that viruses can emerge through routes we haven’t considered. We need to be alert to those risks and ready to act on them,” said Ann Moscona of New York’s Weill Cornell Medical College.