Influenza A Virus in Sea Otters

It is very well known that the Influenza A Virus is capable of infecting an ever greater number of mammals, marine animals among them. While we have already extensively written about infected seals and whales, scientists were still surprised to find[1] that northern sea otters (Enhydra lutris kenyoni) living off the coast of Washington state (USA) in the north-western Pacific Ocean could become infected with Influenza A(H1N1) Virus.

During an August 2011 health monitoring project, scientists found evidence that the Washington sea otters were infected with the pandemic 2009 H1N1 virus, although the exact date and source of exposure could not be determined. These findings do suggest that human flu is very much capable of infecting sea otters. The researchers discovered antibodies for the Influenza A(H1N1) Virus in blood samples from 70 percent of the sea otters studied.

[Image: Mike Baird]

“Our study shows that sea otters may be a newly identified animal host of influenza viruses,” said Hon Ip, one of the scientists.

None of the otters were visibly sick, but the presence of antibodies means that the otters were previously exposed to influenza. Further tests concluded that the antibodies were specific to the human 2009 H1N1 flu virus, and not from exposure to other human or avian H1N1 viruses.

“We are unsure how these animals became infected,” said Zhu-Nan Li, lead author on the paper. “This population of sea otters lives in a relatively remote environment and rarely comes into contact with humans.”

[1] Zhu-Nan Li et al: Serologic Evidence of Influenza A(H1N1)pdm09 Virus in Northern Sea Otters in Emerging Infectious Diseases - 2014