The disgusting, and fascinating, case of the worm in the oyster

If you’ve shucked an oyster from Washington state recently, you might have noticed something new. Black blisters on the meat of the oyster.

Researchers are attributing many of these blisters to a parasite they’ve never seen before.

A warning if you’re sensitive: this story involves tiny worms, shellfish and unsolved mysteries.

You've probably heard of mud worms before — little parasites that can worm their way, literally, into an oyster shell. The worms can have devastating effects —they're blamed for the end of the oyster industry in places such as Australia and South Africa. For a long time Washington shellfish was thought to be spared that wormy fate.

But researchers with the University of Washington have discovered that Washington oysters do contain a kind of mud worm — one no one has ever seen before.