Scientists may have finally identified the culprit behind sea star wasting disease, a condition that's been decimating starfish populations since 2013. Research published Wednesday in Nature Ecology & Evolution points to a bacterium called Vibrio pectenicida as a likely culprit for the disease that causes twisted arms, lesions, and swift death—most notably impacting the sunflower sea star, which has seen its numbers drop by about 91% across multiple outbreaks, per Science News. This loss has ripple effects for marine ecosystems, since sunflower sea stars help control sea urchin populations. Sea urchins consume kelp forests, which are vital for absorbing carbon dioxide and supporting a range of ocean life.
The identification of V. pectenicida is seen as a promising development by marine ecologists. Knowing the pathogen could make it easier to protect and potentially restore sunflower sea stars, even allowing for targeted antibiotic treatments in captivity, says Cornell University's Ian Hewson. He was the lead author of a 2014 study that identified the culprit as a waterborne densovirus, but was unable to replicate the results. This time, researchers put healthy sea stars in tanks where sick sea stars had been, or injected them with fluids from sick starfish. Almost all died within about 12 days.
Genetic analyses revealed V. pectenicida as a potential culprit. Researchers then grew the bacteria, which was injected into six healthy sea stars, killing all. Some skepticism remains; previous studies didn't always find the bacterium in sick animals, possibly due to differences in sampling methods. Still, the findings may help with monitoring and managing future outbreaks. Researchers are now developing rapid diagnostic kits, similar to COVID-19 tests, to quickly identify and respond to new infections in the wild.