Scientists: Bird Flu Virus Linked to New England Seal Deaths #h5n1

Scientists: Bird Flu Virus Linked to New England Seal Deaths

12/20/2011 Reported By: Keith Shortall Learn More.... About Keith Shortall Send Email

Scientists have confirmed the presence of an influenza virus they believe is linked to a spate of harbor seal deaths this fall off the coast of northern New England, including Maine. Researchers have found that some of the dead animals were infected with a subtype of bird flu virus that until now has not been known to kill seals. Since this past September, 162 seals have been found dead off the coasts of Massachusetts, New Hampshire and Maine. Tests on five of the animals showed the presence of influenza virus subtype H3N8, and it's believed that the seals died of bacterial pneumonia associated with the virus. "This seal virus is more closely associated with the wild bird viruses," says Dr. Teri Rowles, lead veterinarian and coordinator of the Marine Mammal Health and Stranding Program for the National Oceanic and Atmospheric Administration. "And this is the first time that this H3N8 subtype and this particular virus has been associated with mortalities in seals." Rowles says this particular influenza subtype has been found in seals before, but has not been associated with deaths. Three previous die-offs back in the early 1980's, she says, all implicated other flu viruses. Dr. Hon Ip, head of the Diagnostic Virology Laboratory at the National Wildlife Health Center, says the H3N8 subtype is very common in birds, and infected mammals have typically recovered. He says it's not clear why it appears to suddenly be killing harbor seals. "And historically it does seem like there are periodic episodes of influenza-caused mortality event in seals, but the number of them has been very few and far between," Ip says. "So it's hard to sort of know what kinds of mutation that there are." Dr. Charles Innes, director of health for the New England Aquarium, says this most recent die-off of 162 mostly young harbor seals is far above the average death rate. "In our experience this number probably around at least three to four times higher than what we typically see in a typical year for young harbor seals that just don't make it because of poor nutrition or disease," Innes says. Scientists involved in the collaborative research effort say additional tests will determine what role the virus played in the broader die-off in northern New England. They say the virus appears to have low risk for transmission to humans. http://www.mpbn.net/News/MaineNewsArchive/tabid/181/ctl/ViewItem/mid/3475/ItemId/19480/Default.aspx