FAIRBANKS, Alaska, Dec. 12 (UPI) -- Veterinarians in Alaska say they don't know what has killed almost 200 arctic ringed seals since July, with similar deaths reported in Canada and Russia.
The mystery ailment causes the animals' hair to fall out and ulcers to develop on their skin and flippers, and necropsies have revealed lesions on their lungs, livers, hearts and brains, NewScientist.com reported Saturday.
"We don't know what's causing it," Julie Speegle of the US National Oceanic and Atmospheric Administration's office in Alaska said, adding tests have ruled out viruses that killed hundreds of seals in Europe in 1988.
Vets said they were screening for other viruses, bacteria and fungi, and for algal and other toxins that may be responsible.
The disease may have spread to other species including spotted seals, bearded seals and walruses, and NOAA has advised hunters not to eat any sick seals in case the agent can also infect humans.