A disease that is killing the starfish, or sea stars, on both coasts of the U.S. is still a mystery, scientists say.

Researchers haven't found what's killing the starfish on the Pacific and Atlantic coasts of North America.

Starfish are not fish, but echinoderms which is why scientists refer to the creatures as sea stars. The organism feeds by using its suckers to hold on to a prey and then dissolving it using an extended stomach.

The new mystery disease is causing the sea stars to lose arms and reducing them to a gooey mess. Several species of the stars are affected by the disease, including sunflower star, Pycnopodia helianthoides, Orthasterias koehleri (rainbow star), Pisaster brevispinus (giant pink star), Pisaster giganteus (giant star), Evasterias troschelii (mottled star),

"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, according Reuters.

Researchers said Thursday that they have ruled out fungi and parasites as a possible cause of the disease, Reuters reported. They are now focusing their attention on bacteria and virus as a potential reason for the wasting disease of sea stars.

The disease was first found in ochre stars (Pisaster ochraceus) in June 2013 along the Washington coast, according to a press release by University of California Santa Cruz, released December last year.

A year later and there is no sign of the disease slowing down.

"I wish we had a sign that it was petering out, but believe me it definitely is not," Harvell told Reuters.

Biologists are worried that the disease might lead to an extinction of sea stars. The wipe-out of an ecologically important organism will lead to reduction in numbers of other creatures or possibly, rise of a new predator. There is also concern that the disease might spread to other marine organisms, according to a report by Physorg.

Erik Stokstad has written an article in Science, describing the disease symptoms and ongoing research. Read the article, here.