The first transmission of a seal-killing virus that started in the Atlantic Ocean has been documented in a population of Pacific sea otters in Alaska.  The transmission of the disease from the Atlantic Ocean to Pacific Sea is the first sign that melting Arctic ice not only affects the habitat of Arctic animals, like polar bears and seals, but also makes it easier for pathogens to travel into the area and into the Arctic wildlife.

The details of the finding appear in the journal Emerging Infectious Diseases, which is published by the U.S. Centers for Disease Control and Prevention. The pathogen –phocine distemper virus (PDV) – killed 30,000 harbor seals in a single outbreak in Northern Europe in 2002. The virus has also affected seal population in Canada’s Atlantic coast.  The passing of the virus, which moved between seal species, took place across Arctic Eurasia or Northern Canada before it was passed on to otters living in the Alaskan Kachemak Bay.

Necropsies were performed on dead otters that were found along the Alaskan shore and some nasal swabs were taken from living otters.  Both showed that the Atlantic virus had hit the Pacific population of otters.

According to researchers from the Alaskan branch of the U.S. Fish and Wildlife Service, along with researcher from two California universities, before this PDV “had never been identified as the cause of illness or death in the North Pacific Ocean.”

Scientists believe that PDV suppresses the immune system of the otters, allowing, in some cases, a deadly strep infection to take hold.

In their study, the scientists concluded that, “These results demonstrate that PDV has been introduced to the North Pacific Ocean since 2000. All Pacific marine mammal species are now at risk for phocine distemper-induced population decreases.”

The scientists also concluded that the melting of the Arctic ice may have been a main factor in the travel of the virus from the Atlantic Ocean into Alaskan waters.

“The decrease in sea ice may have affected movement of Arctic seal populations … This sea ice reduction may have altered seal haul out and migration patterns, resulting in contact between Atlantic, Arctic, and Pacific Ocean species that was not possible [before].”