HAMPTON — Scientists studying why more than a hundred harbor seals died along the New England coastline last year have released a new report that shows the seals perished as a result of a new strain of avian flu capable of being transmitted from birds to mammals, possibly humans.
The report — Emergence of Fatal Avian Influenza in New England Harbor Seals — was released Tuesday by a team of experts tasked with uncovering why 162 young seals turned up dead on Seacoast beaches including Hampton Beach, last fall.
In the report, researchers identify the cause of death as an influenza A virus "H3N8," a new strain of the bird flu that can jump from birds to marine mammals, such as seals and sea lions.
The report was made possible by scientists at the Center for Infection and Immunity at Columbia University's Mailman School of Public Health, the U.S. National Oceanic and Atmospheric Administration, New England Aquarium, the U.S. Geological Survey National Wildlife Health Center, SeaWorld and EcoHealth Alliance.
Simon Anthony, a postdoctoral researcher at the Center for Infection and Immunity at Columbia University, was the lead author of the study.
"When initial tests revealed an avian influenza virus, we asked the obvious question: how did this virus jump from birds to seals?" Anthony said.
The report states that the emergence of new strains of influenza virus is always of great public concern, especially when the infection of a new mammalian host has the potential to result in a widespread outbreak of disease.
"This outbreak is particularly significant, not only because of the disease it caused in seals but also because the virus has naturally acquired mutations that are known to increase transmissibility and virulence in mammals," the report states.
W. Ian Lipkin, director of the Center for Infection and Immunity and John Snow, professor of epidemiology at the Mailman School of Public Health, said the findings reinforce the importance of wildlife surveillance in predicting and preventing pandemics.
"HIV/AIDS, SARS, West Nile, Nipah and influenza are all examples of emerging infectious diseases that originated in animals," he said. "Any outbreak of disease in domestic animals or wildlife, while an immediate threat to wildlife conservation, must also be considered potentially hazardous to humans."
Katie Pugliares, a senior biologist with the New England Aquarium's rescue program, also assisted in the new report.
Pugliares said that while the study indicated that the newly identified virus can be passed to mammals, so far there is no indication that humans are capable of contracting it.
"We don't believe this particular strain is harmful to people because of the number of personnel we had handling them — nobody got sick," she said.
Pugliares said at this point experts believe H3N8 is a mutation from a strain of bird flu, which is something she said happens, but only on rare occasions.
"Viruses mutate so they can jump from one host to the next," she said. "What's alarming is that it was able to mutate and adapt to mammals."
How die-off began
Pugliares said she remembers exactly when the surge in seal deaths became apparent last fall. It was a Wednesday evening and a beachgoer in Seabrook had called in to report a dead seal on the beach, according to Pugliares.
"(The beachgoer) took a photo and sent it to us," she said. "We immediately saw that something interesting was going on with that one animal."
Red flags began to pop up when experts noticed the dead seal appeared to be in good condition, Pugliares said. Shortly after receiving the image from the beachgoer, Pugliares said a staff member from New England Aquarium was dispatched to Seabrook to see what else he or she could learn.
While en route to the beach, Pugliares said the Boston-based aquarium got a phone call from an employee at a surf shop in Rye reporting that surfers were bumping into dead seals floating in the water.
When experts arrived at the local beach, Pugliares said six dead seals were found scattered across the sand. While dead seals washing ashore is considered routine, Pugliares said it was clear something strange was happening.
Then, in December, Pugliares said experts discovered that an Influenza A-type virus was responsible for the seal deaths.
"It was at that point that we knew this was an infectious disease," she said.
Scientists tasked with identifying the virus then determined that the next closest flu came from a species of birds that was identified in 2002.
Officials from the National Oceanic and Atmospheric Administration then declared the seal deaths an "unusual mortality event," which prompted attention at the national level and eventually resulted in the recent study.
On the lookout
The late summer months are perhaps the busiest times... http://www.seacoastonline.com/apps/pbcs.dll/article?AID=/20120807/NEWS/208070346/-1/NEWSMAP