Scientists Identify the Mysterious Virus that Causes Sea Stars to Melt

Scientists have uncovered the virus behind disintegrating starfish. Not only that, but they've discovered what's behind the disease's sudden appearance, which has decimated sea stars on the North American Pacific Coast.

The microbe responsible for the disease, called Sea Star Wasting Disease (SSWD), is known as the Sea Star Associated Densovirus (SSaDV) virus. This microbe is responsible for the largest die-off of sea stars ever recorded. In fact, since June 2013, at least 20 different species of sea stars have been affected.

And yet this virus isn't something that's new. It's existed at a low level for at least the past 72 years, according to museum samples. Yet it's possible that the disease recently rose to epidemic levels due to sea star overpopulation and environmental changes. It's also possible that the virus recently mutated.

"There are 10 million viruses in a drop of seawater, so discovering the virus associated with a marine disease can be like looking for a needle in a haystack," said Ian Hewson, one of the researchers, in a news release.

In this case, the scientists detected this particular virus on particles suspended in seawater, as well as in sediment. This virus isn't just harbored in sea stars, though; it's also found in animals related to sea stars, such as sea urchins and brittle stars.

What's disturbing is that this virus is likely to cause long-lasting ecological impacts on coastal habitats. Currently, the researchers hope to identify the factors that triggered the ongoing plague in order to help predict or forestall similar events in the future.

As the virus continues to spread, sea stars are changing their behaviors, developing lesions, losing their limbs and eventually disintegrating. Finding out how to halt the spread of this disease may be a huge step forward when it comes to preventing future ecological impacts.

The findings are published in the journal Proceedings of the National Academy of Sciences.