H1N1 Virus Detected in Marine Mammals for the First Time

A new finding, published in the journal PLOS ONE, reports the first flu strain ever found in any marine mammal. Researchers at the University of California, Davis, discovered the H1N1 virus in northern elephant seals off the central California cost.

The case of H1N1 in marine mammals was detected a year after the human pandemic began. Since 2007, U.S. researchers have been studying flu in wild birds and mammals as part of the Centers of Excellence in Influenza Research and Surveillance program. The main aim of this program was to track the mechanism behind how viruses emerge and spread among animals and humans.

"We thought we might find influenza viruses, which have been found before in marine mammals, but we did not expect to find pandemic H1N1," lead author Tracey Goldstein, an associate professor with the UC Davis One Health Institute and Wildlife Health Center, said in a press statement. "This shows influenza viruses can move among species."

Researchers tested the nasal swabs of more than 900 marine mammals that belonged to 10 different species off the Pacific Coast from Alaska to California, from 2009-2011. They discovered the H1N1 infection in two northern elephant seals, and antibodies to the virus in another 28 seals. This clearly indicated extensive exposure to the virus. To their surprise, the infected seals didn't appear ill, indicating that marine mammals may be infected with H1N1 but do not display any symptoms of being ill.

In early 2010, the seals on land tested negative before they headed out to sea, but were tested positive on returning from the sea during spring 2010. Researchers were not sure as to how they contacted the virus, since when they are at sea, they spend most of their time foraging in the northeast Pacific Ocean, where human contact is unlikely. On tracking the seals, they predict that exposure to the virus took place before they reached land, either while at sea or upon entering the near-shore environment.

The study is relevant to those who deal with marine mammals, such as animal rescue, rehabilitation workers and veterinarians. Simultaneously, it highlights the importance of wearing protective gear in order to avoid workers' exposure to the diseases, and also prevent the transmission of disease from humans to animals.