We’ve a follow up from NOAA today on the mysterious deaths of seals along the New England coastline earlier this fall. In early November I reported (see NOAA: New England Dead Seals Test Positive For Flu) that initial tests indicated an influenza A virus, but more testing was needed to determine the exact strain.
In the past, we’ve seen rare and isolated influenza infections resulting in seal deaths from the H7N7 and H4N5 avian flu viruses.
Today we learn that the viral culprit in this latest incident is a variant of the H3N8 avian flu strain, versions of which are known to also infect horses and dogs.
My thanks to @JustinNOAA for the link to this news release.
Risk to humans and pets low; tests continue
Harbor Seals (Credit NOAA)
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."