WASHINGTON - Scientists are struggling to find the cause of a disease that is killing off numerous species of starfish on both the Pacific and Atlantic coasts of North America, dispatching the five-armed creatures in a particularly gruesome way.
Researchers said on Thursday they have ruled out some possible culprits including fungi, some parasites and certain other microorganisms and are taking a hard look at whether viruses or bacteria may be to blame.
The starfish, also called sea stars, are being obliterated by an unexplained wasting disease that causes white lesions to appear before the animal's body sags and ruptures and it spills out its internal organs.
"The magnitude of it is very concerning.There's the potential that some of these species could actually go extinct,"said Cornell University ecologist Drew Harvell, one of the scientists involved in the loosely organised search for a cause.
Harvell said she is concerned because the mysterious pathogen is affecting 18 different West Coast species along their entire range.
Pathogens that affect an animal's range in such a way like a fungus that has targeted frogs can be particularly damaging, she said.
The disease appeared last year and is showing no indication of abating. "I wish we had a sign that it was petering out, but believe me it definitely is not," Harvell said.
The scientists seem to have more questions than answers.
"What is it that has caused this? Where did it come from? If it's exotic, how did it get here? Is it something that's likely to be repeated?" asked Pete Raimondi, chairman of the Department of Ecology and Evolutionary Biology at the University of California, Santa Cruz.