Sea stars are famed for their multiple arms, ability to regenerate limbs, and colorful camouflage. While more than 2,000 species of sea stars inhabit the world’s oceans, millions of these creatures have died from sea star wasting disease (SSWD) within the past 18 months. SSWD begins when a sea star’s arms curl up, and grotesquely concludes when the entire animal disintegrates. Scientists now believe that this mysterious epidemic is caused by a virus.
Cornell University’s Ian Hewson first suspected that a virus, or other small infectious agent, might be responsible for SSWD after observing that sea stars living in aquariums with ultraviolet light-treated water remained healthy, whereas those living in tanks with untreated water frequently fell ill. To test this idea, Hewson’s team injected tissue from infected sea stars into healthy ones, and observed that the formerly healthy sea stars became sick within three weeks. However, when these same tissue samples were heated (to kill any viruses that might be present), the injected sea stars stayed healthy. Perhaps most intriguing is the discovery that the virus in question has existed in sea stars for over 70 years, but has decimated sea star populations only recently.
Acknowledgments: Many thanks to Heather Olins, a graduate student in the Department of Organismic and Evolutionary Biology at Harvard University, for her expertise and commentary on the topic.
Managing Editor: Laura L. Smith
Scientists Find Likely Culprit Behind Mysterious Sea Star Deaths (LA Times)
Sea Star Wasting Syndrome (UC Santa Cruz)