Clinical and Clinical Laboratory Correlates in Sea Otters Dying Unexpectedly in Rehabilitation Centers Following the Exxon Valdez Oil Spill

Following the Exxon Vuldez oil spill, 347 oiled sea otters (Enhydra lutris) were treated in reha- bilitation centers. Of these, 1 16 died, 94 within 10 days of presentation. Clinical records of 2 1 otters dying during the first 10 days of rehabilitation were reviewed to define the laboratory abnormalities and clinical syndromes associated with these unexpected deaths. The most common terminal syndrome was shock char- acterized by hypothermia, lethargy, and often hemorrhagic diarrhea. In heavily and moderately oiled otters, shock developed within 48 hours of initial presentation, whereas in lightly oiled otters shock generally occurred during the second week of captivity. Accompanying laboratory abnormalities included leukopenia with increased numbers of immature neutrophils (degenerative left shift), lymphopenia, anemia, azotemia (primarily prerenal), hyperkalemia, hypoproteinemiahypoalbuminemia, elevations of serum transaminases, and hypoglycemia. Shock associated with hemorrhagic diarrhea probably occurred either as a direct primary effect of oiling or as an indirect effect secondary to confinement and handling in the rehabilitation centers. Lightly oiled otters were less likely to die from shock than were heavily oiled otters (22% vs. 72%, respectively). Heavily oiled otters developed shock more rapidly and had greater numbers of laboratory abnormalities, suggesting that exposure to oil was an important contributing factor. Following the oil spill caused by the grounding of the Exxon Vuldez oil tanker in Alaska's Prince William Sound, a major effort was made to treat oiled sea otters (Enhydra lutris) in rehabilitation centers in an attempt to return them to the wild. A total of 347 sea otters were presented to the rehabilitation centers for treat- ment. Of these 347 sea otters, 116 died while at the centers, 94 (81%) within the first 10 days of presen- tation. The gross pathologic and histopathologic alter- ations in otters that died unexpectedly in the centers have been de~cribed.~.~ In this report, we present the clinical findings and principal laboratory changes in otters that died within the first 10 days after entering the rehabilitation centers regardless of degree of oiling or approach to therapy.