Scientists have linked the decline in Arctic sea ice to the __26___ of a deadly virus that could threaten marine mammals in the North Pacific, __27___a study from the University of California, Davis. Phocine distemper virus, or PDV, a pathogen responsible for killing thousands of European harbor seals in the North Atlantic in 2002, was identified in northern sea otters in Alaska in 2004, __28___ questions about when and how the virus reached them. The 15-year study, published today in the journal Scientific Reports, __29___ how the radical reshaping of historic sea ice may have opened pathways for contact between Arctic and sub-Arctic seals that was previously impossible. This __30___the virus’ introduction into the Northern Pacific Ocean.