Four years ago I published a paper that identified the sea star associated densovirus (SSaDV) as the best candidate culprit for sea star wasting disease. Eight months later, my dad passed away from a rare condition called “myelodysplastic syndrome”, which is a heterogeneous group of diseases that manifest with similar symptoms. Often in biology and science it is easier to describe common signs and observations as a single condition, to seek out one explanation for that phenomena. It is easier to explain, easier to spark interest, and easier to change in the future. But biology is seldom easy. Myelodysplastic syndrome made me aware that sometimes there are multiple conditions that resemble the same disease – which is made even more valid a possibility when one considers the relative simplicity (in terms of responses) of sea stars to stress. In short, how many ways can a sea star tell us that they’re unwell?
After 4 years of investigation by some of the most dedicated and awesome grad students, undergraduate assistants, technicians and citizen scientists, we have found great difficulty in replicating “sea star wasting disease” in the lab. When we first found SSaDV hiding in viruses that inhabited sea star tissues, we had little clue that densoviruses are pretty diverse and routinely found in association with sea stars. Refining our observations to potentially exclude similar densoviruses that we hadn’t seen necessarily associated with any wasting demonstrated that SSaDV wasn’t in any clear way associated with wasting disease in species other than the one for which we had a pretty firm case in 2014 – the sunflower star, Pycnopodia helianthoides. Our previous observation of SSaDV in historical samples from 1942 to present also was not confirmed by this new approach – densoviruses observed in wasting sea stars were only seen from 2013 to present. Further analyses of other potential factors (which is by no means exhaustive) both pathogenic and climatological failed to yield any single or even potentially combination of factors that explained the occurrence of SSWD amongst all species in which it has been observed. In the absence of any explanatory variable, the logical explanation is that SSWD is probably not a solitary disease, but rather a syndrome of common disease signs between species, and even amongst the same species at different locations. SSaDV remains our prime candidate associated with wasting in sunflower stars – but the same cannot be said for other commonly affected stars, like the ochre star Pisaster ochraceus, or mottled star Evasterias troscheli.
Hence, we propose the new scientific title for sea star wasting disease: Asteroid idiopathic wasting syndrome. Asteroid means sea stars. Idiopathic means that it arises spontaneously and is caused by unknown factors. And syndrome means a series of correlated disease signs.
This new paper can be found in the journal Frontiers in Marine Science at:
Cornell Marine Mass Mortality Laboratory 