Abstract

In January 2005 an adult male northern sea otter, ELs-05-01 stranded in Seward, Alaska. On presentation to the Alaska SeaLife Center (ASLC) rehabilitation program, the animal was underweight and had infected puncture wounds on its right forepaw with underlying broken bones. Neurologic signs were first noted 1 wk later and consisted of catatonia, partial paralysis, and fine muscle fasciculations. ASLC collaborates with the U.S. Fish and Wildlife Service (USFWS) on a northern sea otter disease screening project whose goal is to better understand factors that might be contributing to the decline or constraining the recovery of this species, recently listed as threatened in part of its range. As part of this project ASLC routinely sends out serum and other samples for serologic and microbiologic testing. As a result of this program this animal was found to be positive for antibodies to toxoplasmosis. While neurologic signs resolved following 2 wk of ponazuril (Marquis, Bayer HealthCare LLC, Animal Health Division, Shawnee Mission, KS, USA) 10 mg/kg, p.o. s.i.d., treatment was continued for 60 days. The medication was placed in the mantel cavity of a squid which was refrozen to prevent the otter from removing the medication. Staff ensured the ‘med-squid’ was eaten prior to feeding the rest of the diet. Surgical removal of sequestra in the otter’s right forepaw and treatment with antibiotics allowed these wounds to heal. Following cessation of all medication, the otter was observed for an additional month at ASLC and was released at the end of May 2005. After release, the otter was observed multiple times in the area, eating and behaving normally. While toxoplasmosis is common in southern sea otters, this finding is a first for northern sea otters in Alaska. Since this case, additional northern sea otters in Alaska have tested positive for antibodies to toxoplasmosis. These animals were caught during USFWS capture trips. This report will put this finding in context with the different patterns of disease and mortality seen in southern versus northern sea otters.