Ian Hewson

Late last summer, Cornell scientists identified a killer virus that has devastated starfish along the west coast of North America, threatening coastal marine ecosystems from Mexico to Alaska 

Rapid Response to Sea Star Wasting Disease Nets a Killer

December 10, 2014

Ian Hewson

Late last summer, Cornell scientists identified a killer virus that has devastated starfish along the west coast of North America, threatening coastal marine ecosystems from Mexico to Alaska.

The groundbreaking genomic detective work that determined a densovirus is the likely cause of sea star wasting disease started with a Rapid Response Fund (RRF) grant soon after the first sightings of the disfiguring, deadly disease surfaced in the tidal waters of the Pacific Northwest.

Microbiologist Ian Hewson and marine ecologist Drew Harvell approached the Atkinson Center with reports of a horrific die-off that needed urgent study. The sea stars develop lesions, their arms fall off, their guts spill out, and finally they die. The mortality rate is staggeringly high. More than 20 species are affected, and entire colonies wiped out.

With an RRF grant in hand, Hewson, Harvell, and a team of students began collecting and examining tissue samples and identified the Sea Star–associated Densovirus (SSaDV) as the likely killer.

“Sea stars, like humans, are literally swarming with microorganisms when they are healthy—a soup known as the microbiome—so finding a virus associated with a disease is like finding a needle in a haystack,” says Hewson.

The project secured additional funding and grew to include researchers at several universities and a network of students and citizen scientists, who fed their field observations into a giant database at Cornell’s Center for Computational Sustainability. With worldwide attention focused on the deaths, legislation was introduced in Congress to supply emergency funding for future marine disease outbreaks.

The human response to the plight of this sea creature surprised Harvell and Hewson, whose research typically takes place in relative obscurity. A fifth-grade class in Arkansas raised money to support the research. When the findings were first reported in November in the Proceedings of the National Academy of Sciences, more than 400 news outlets reported the story.

“The loss of an iconic marine organism for previously unknown reasons was like an environmental whodunit that captured the imagination of people—from students in landlocked states to concerned citizens living adjacent to affected areas—like nothing I’ve seen before,” Hewson remarks.

The team’s next step is to figure out why starfish today are so vulnerable to the virus, which Hewson has found in healthy museum samples collected as early as 1942.

The die-off is already affecting underwater life in the areas hardest hit, where mussels and other mollusks—a starfish’s favorite foods—are rapidly multiplying.

“It’s the experiment of the century for marine ecologists,” says Harvell. “It is happening at such a large scale to the most important predators of the tidal and subtidal zones. Their disappearance is an experiment in ecological upheaval the likes of which we’ve never seen.”