Scientists say they have solved the mystery of what killed more than 5 billion sea stars

Scientists say they have at last solved the mystery of what killed more than 5 billion sea stars off the Pacific coast of North America in a decade-long epidemic. Sea stars – often known as starfish – typically have five arms and some species sport up to 24 arms. Starting in 2013, a mysterious sea star wasting disease sparked a mass die-off from Mexico to Alaska.