The swine flu virus that caused a 2009 pandemic has been found in elephant seals off the central California coast, according to new research.
The study, published in the journal PLoS ONE, is the first report of the virus H1N1 in any marine mammal.
Researchers are now being advised to wear protective personal gear when working around marine mammals, to avoid the possibility of infection.
“H1N1 was circulating in humans in 2009,” lead author Tracey Goldstein said in a press release. “The seals on land in early 2010 tested negative before they went to sea, but when they returned from sea in spring 2010, they tested positive. So the question is where did it come from?”
“We thought we might find influenza viruses, which have been found before in marine mammals, but we did not expect to find pandemic H1N1,” said Goldstein, an associate professor at the University of California at Davis. “This shows influenza viruses can move among species.”
Goldstein and other UC Davis researchers have been studying flu viruses in wild birds and mammals since 2007. For this study, they tested nasal swabs from more than 900 marine mammals from 10 different species off the Pacific Coast from Alaska to California.
They detected H1N1 infection in two northern elephant seals and antibodies to the virus in an additional 28 elephant seals, indicating more widespread exposure. Neither infected seal appeared to be ill, indicating marine mammals may be infected without showing clinical signs of illness.
“The study of influenza virus infections in unusual hosts, such as elephant seals,” said co-author Adolfo Garcia-Sastre, “is likely to provide us with clues to understand the ability of influenza virus to jump from one host to another and initiate pandemics.”
Image: Tracey Goldstein/UC Davis