A virus similar to one found in birds but never before in harbor seals was the cause of five of 162 recent deaths of the animals  in New England, according to a group of federal agencies and private partners.

This Influenza A virus subtype, H3N8, appears to have a low risk of transmission to humans. Experts continue to analyze this virus, and any findings of public health significance will be immediately released. The virus is not the infamous H5N1  virus that caused a global pandemic in 2007, or the H1N1 virus from 2009.

Any member of the public who sees a seal in distress is reminded to:

• Stay at least 150 feet away
• Keep dogs leashed and away from seals
• Call NOAA Fisheries Service´s stranding hotline at 1-866-755-NOAA (6622)

“The work that NOAA and its partners have done to help identify and confirm the virus strain H3N8 in these animals has been an important first step in the investigation into this event,” said Dr. Teri Rowles, lead veterinarian and coordinator of the Marine Mammal Health and Stranding Program for NOAA Fisheries Service. “We are now conducting tests on additional animals to learn more about the role this virus may have played in the die-off and to better understand the virus itself.”

Experts believe that Influenza A virus caused a bacterial pneumonia which was responsible for the death of the five seals. Most terrestrial animals infected with the previously known H3N8 virus suffered upper respiratory infections, and most recovered.

"This H3N8 virus is usually associated with wild birds, and a separate group of H3N8 infects horses and dogs,” said Dr. Hon Ip, of the USGS’s National Wildlife Health Center. "This is the first time that a virus which is similar to the H3N8 avian influenza virus has been associated with a large scale mortality in marine mammals."

The New England Aquarium collected the original samples as part of the Northeast Stranding Network and submitted them for evaluation to various laboratories. The medical team from SeaWorld assisted in the sample evaluation and directed diagnostics. The Center for Infection and Immunity at Columbia University’s Mailman School of Public Health and the EcoHealth Alliance identified and typed the virus, which was subsequently confirmed by the Connecticut Veterinary Diagnostic Laboratory and the USGS National Wildlife Health Center. The Centers for Disease Control also contributed to the effort.

“New England Aquarium has been contributing to marine mammal rescue, rehabilitation, and disease surveillance for several decades as a member of NOAA’s stranding program,” said Dr. Charles Innis, director of health, New England Aquarium. “This recent investigation highlights the value of having a collaborative team of partners both in the field and in the lab identifying diseases that could be dangerous for wildlife, humans, and domestic animals.”

Since Sept. 1, 2011, members of NOAA’s stranding network, including the New England Aquarium’s Marine Mammal Rescue Program and the University of New England´s Marine Animal Rescue Center, have responded to 162 seal deaths in Maine, New Hampshire and northern Massachusetts.

An investigative team consisting of staff from diagnostic laboratories, pathologists, veterinarians and marine mammal experts, has been formally convened since the recent mortalities were declared an “unusual mortality event” on November 3. The investigative team has been working closely with NOAA, New England Stranding Network partners and the Working Group on Marine Mammal Unusual Mortality Events to gather additional information and conduct further analyses.

The Marine Mammal Protection Act defines an unusual mortality event as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response." To learn more about unusual mortality events and to follow progress on the investigation into this event, please visit http://www.nmfs.noaa.gov/pr/health/mmume/.