Exertional myopathy in translocated river otters from New York

Lesions consistent with exertional myopathy (EM) were documented postmortem in four North American river otters (Lutra canadensis) during translocatio n for a population restoration project. Clinical signs in these otters incl uded depression, anorexia and shock. Gross lesions in one otter included lo cally extensive linear, pale areas within the subscapularis, rectus abdomin is, quadriceps, and dorsal laryngeal muscles. Microscopic lesions were char acterized by acute to subacute myofiber necrosis of varying severity, and o ccurred in a variety of skeletal muscles as well as cardiac muscle in one o tter. Based on these observations, we conducted a retrospective review of r ecords of otters which experienced similar capture, transfer and holding pr otocols between 1995 and 1997, but with a successful outcome (n = 69). Sign ificant elevations in serum aspartate aminotransferase (AST) and creatine k inase (CK) were observed in 19 (28%) of the otters, but may have been highe r due to delayed sample collection from some otters. However, none of the o tters with elevated enzymes exhibited clinical signs suggestive of EM. Thes e findings indicate that river otters may develop EM when translocated, but many cases may be mild or clinically inapparent.