For about four months last year the bodies of 162 seals washed up on
beaches in New England. Most of the seals were pups under six months
old. The cause of death was not immediately apparent. Testing turned up
an answer that has researchers concerned -- it was a new strain of
influenza that they believe the seals caught from birds.
The concern stems from the fact that this flu has natural mutations that can make it a threat to mammals, including humans. This new strain is H3N8, a category that includes flu that infects dogs and horses.
Many animals can get a type of flu, known as Influenza A,
and these viruses can make their way to humans with certain mutations. Wild
birds are the most likely natural source of Influenza A, however, the
viruses can jump from one species to another. The viruses can mix with one another with potentially devastating results. The deadly H1N1 pandemic in 2009 and the Spanish flu pandemic at the end of World War 1 are examples of what a mix of these viruses can do.
The new seal-killing virus has made the transition from
birds fairly recently, undergoing the same mutations that have helped
flu viruses adapt to new species in the past. Genetic tests have indicated the new virus has descended from a
strain that has been around in
water birds since 2002. The changes seen in the new virus at this point suggest
it may continue infecting seals and evolve into a new
branch of H3N8.
It is not clear yet whether or not this new virus poses a threat
Source: NBC News