Bird flu virus tied to New England seal deaths - 23rd Dec 2011

An influenza virus similar to one found in wild birds but never before seen in seals has been linked to the recent spate of harbor seal deaths off northern New England, scientists said Tuesday.

Since Sept. 1, 162 seals have been found dead from northern Massachusetts to Maine.

The die-off struck young seals and was most intense in September and October, when deaths were about three to four times the normal number, said Charles Innes, the New England Aquarium's health director. The death rate has since slowed to normal levels.

Tests on five of the dead animals - all from New Hampshire - showed they suffered a bacterial pneumonia caused by the influenza virus subtype, H3N8. Tests are continuing to determine what role the virus played in the broader seal die-off, researchers said.

Besides birds, a separate group of H3N8 hits horses and dogs, but those animals generally recover.

Scientists said the virus appears to have low risk for transmission to humans. But Catherine Brown, State Public Health Veterinarian in Massachusetts, said when influenza jumps between species, it's important to try to learn why.

"Every time that happens, the more we can learn about what causes that to happen, the more we can actually work to prevent it from happening and protect human health as well as animal health," she said.

Other influenza viruses have been linked to at least three previous seal die-offs in New England since 1979. Read More