PORTLAND. Ore. -

A mysterious disease that causes sea stars to disintegrate is exploding on the Oregon Coast.

Oregon State University marine ecologist Kristen Milligan said Wednesday that Oregon was largely spared last year as the disease known as sea star wasting syndrome spread in California, Washington, British Columbia and Alaska.

But monitoring of tide pools along much of the coast shows the number of sea stars affected has jumped from just 1 percent in April to as high as 50 percent. The greatest concentration is at Fogarty Creek north of Depoe Bay.

Milligan says the cause of the disease is still unknown, but losing so many sea stars - a major predator on mussels and sea urchins - could throw the marine ecosystem out of balance.