US scientists are hoping to uncover answers behind a mysterious disease that has emerged in Arctic seal populations, causing skin lesions, lethargy and death, officials said Friday. Since July there have been at least 107 recorded cases of stranded ringed seals on the north coast of Alaska, said researchers with the National Oceanic and Atmospheric Administration (NOAA) Fisheries and other international groups. The seals have been seen with skin lesions, hair loss and skin ulcers, while some have exhibited lethargy and labored breathing, officials said. Nearly half of the animals were dead when found, or died shortly after, said NOAA in a statement. Similar cases of the mystery illness have been reported in Russia and Canada, as well as in some walruses in Alaska. Lab tests for the disease's origin have been "inconclusive," and officials said it "is not known if the condition can be passed from the seals to humans." NOAA warned against eating any sick or diseased animals or handling them without proper protection garments.