This is the most recent thing I can find:
The mysteries behind what made Alaska seals and walrus sick last year and caused bald spots on polar bears this spring largely remain unanswered.
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"We do not yet know the cause," NOAA spokesperson Julie Speegle said via email. The event now includes all four species of ice seals (spotted, bearded, ring and ribbon) and Pacific walrus. "We hope to find out what it is."
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Alaska Native hunters who rely on the animals for food, clothing and to make artwork and handicrafts find the lack of answers unsettling. Bird flu and other flus have been ruled out, as have a host of other known viruses.
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Some suggest that the seals may have come into contact with an ocean pollutant, perhaps from a waste-dumping ship. Goodman said he doesn't believe the ocean is polluted, but thinks a one-time exposure from a single ship is plausible. It would also explain, he said, the hair loss that polar bears were found to have this year, much of it near the head and neck. If they were swimming, that's where they'd come into contact with it, he theorized.
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As researchers continue looking, they’re also awaiting the results of more in-depth radiation testing (in February, NOAA said early tests showed contamination from Japan's Fukoshima power plant disaster was an unlikely cause) and are looking at the ocean environment for possible clues. Water temperature, sea ice condition, ocean salinity and pH, in addition to food sources, are aspects of the seals' marine ecosystem that are also under investigation.
"At this point we are thinking it may be a combination of factors," Speegle said. The theory is, something is weakening the animals' immune systems and in a more weakened state they are more susceptible to illness.
An updated report from NOAA is due out at end of the week.
Source
So, nothing definitve yet and a lot of hedgeing.
