drew harvell is coordinating nationwide research into understanding the wasting syndrome and has been studying marine diseases for decades. >> this is the largest disease outbreak that we know of ever in the oceans in terms of the numbers of species affected, in terms of the geographic scale, and in terms of the mortality that's associate with it. >> reporter: after analyzing countless samples in the lab, harvell's team believes that an infectious pathogen-- like a bacteria or virus-- may be the root of the problem. >> this is what we call a wide host range pathogen. it means that it affects many different species. and those are the most dangerous in wildlife disease in terms of a potential risk of extinction. >> reporter: they've learned the syndrome seems to spread through water and physical contact. and they're testing a hypothesis that the pathogen may be transferred through shellfish, which starfish like to eat. exactly what triggers these outbreaks is still unknown, but scientists think the disease could be compounded by warming waters. starfish are stressed by higher temperatur