Bird Flu Strain Kills Harbor Seals: Are Humans Next?

A strain of avian influenza has mutated from birds to aquatic mammals, worrying scientists.

Last fall, 162 seals were found dead along the New England coast, stretching from southern Maine to northern Massachusetts. (Photo: Jeremy Cram Photography/Getty Images)

Jul 31, 2012
Kelly Zhou has written on a variety of topics for TakePart, predominantly politics, education, and wildlife.

A new strain of bird flu that has spread to seals off the coast of New England has scientists worried about a potential threat to humans.

Last fall, 162 harbor seals were found dead along the northeastern coastline, from southern Maine to northern Massachusetts. Most were infant seals, less than six months old, and had severe pneumonia and skin lesions. Scientists at Columbia University’s Mailman School of Public Health and other institutions discovered that a new strain of bird flu, or avian influenza, was responsible for the pneumonia that killed the seals.

MORE: Bird Flu Transmission: How Many Mutations Away?

"When initial tests revealed an avian influenza virus, we asked the obvious question: How did this virus jump from birds to seals?" Simon Anthony, a postdoctoral research scientist at Columbia University’s Center for Infection and Immunity, said in a news release.

Anthony is the lead author of a study published in the journal mBio this week that outlines the significance to humans: the virus has managed to mutate from birds to seals, making it more transmissible in mammals.

The researchers found that this strain of the virus, called seal H3N8, came from an avian strain that has been present in North American birds since 2002, making the transmissions to seals fairly recent. Other H3N8 strains affect dogs and horses.

"Our findings reinforce the importance of wildlife surveillance in predicting and preventing pandemics," W. Ian Lipkin, director of Mailman's Center for Infection and Immunity, said in the release. "HIV/AIDS, SARS, West Nile, Nipah and influenza are all examples of emerging infectious diseases that originated in animals."

MORE: Human-Animal Diseases Kill 2.2 Million People a Year

Two recent studies have been published on the topic of bird flu that discuss the potential spread of the H5N1 virus and human-to-human contact. The papers almost didn't see the light of day, due to requests from biosecurity officials who feared the information would land in terrorists' hands.

As for seal flu, the mutations found by researchers suggest that it may be especially infectious in mammals, but more study is needed. In any case, there could be a potential threat to public health.

"Any outbreak of disease in domestic animals or wildlife, while an immediate threat to wildlife conservation, must also be considered potentially hazardous to humans," Lipkin said.

Do you think we should be worried about the spread of bird flu? Let us know in the comments.

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