Researchers from UC Davis have found swine flu in elephant seals off the central California coast.
UC Davis professor Tracey Goldstein told the Contra Costa Times that while the H1N1 virus commonly crosses species barriers, this was the first time researchers found a human pandemic strain in marine mammals.
"Most of the other viruses that we see in marine mammals tend to be more linked with bird influenzas, and I think that was the surprise," Goldstein said. "Where did this human one come from?"
The seals, however, did not show any clinical signs of the illness, which they contracted in 2010.
While researchers are not sure exactly how the animals contracted the virus, they did say that it is more likely from contact with seabirds than with people.
"The data suggest the animals were exposed when they were at sea, or coming into the nearshore environment," Goldstein said.
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The researchers, all UC Davis wildlife biologists, swabbed the noses of 72 elephant seals over the course of two years at Ano Nuevo State Reserve in San Mateo County and Piedras Blancas in San Simeon, both before and after their annual spring trip to Alaskan waters.
Two elephant seals were found to have H1N1 and another 28 had antibodies to the virus, which was believed to mean there had been widespread exposure.
The university said in a statement that the research was meant to look into how viruses emerge and travel among animals and people. More than 900 marine mammals from 10 different species had their nasal swabs tested between 2009 and 2011.