Abstract

Since around 1985, southwest Alaskan northern sea otters have declined catastrophically, exceeding 90% in some areas. In 2002, a sea otter screening program showed a leading cause of death in beach-cast otters from Homer, south-central Alaska, was infectious disease with a large percentage of otters shedding Streptococcus bovis/equinus complex spp. (SBE). Having a large proportion of animals die of a single infectious disease condition is unusual. To better understand this disease, samples from presumed-healthy, wild-caught, and captive northern sea otters were screened for fecal pathogens. Of 43 wild caught animals, one was culture positive for SBE, two for Campylobacter, six for Clostridium, four for Vibrio, and one for Pleisomonas. None of 16 captive animals were culture positive for SBE, two were positive for Campylobacter, one for Clostridium, three for Vibrio, and none for Pleisomonas. No wild-caught or captive animal grew Salmonella or pathogenic E. coli. Fecal pathogens were cultured from 11 (25.6%) wild animals and five (33.3%) captive animals; samples from three wild animals and one captive animal grew two pathogens. All otters appeared healthy on exam and had no signs of illness despite presence of bacteria which causes gastrointestinal illness in humans. The high percentage of SBE in stranded animals compared to its virtual absence in apparently healthy animals underscores the unusual nature of the mortality event. Additionally, the frequent identification of organisms that can cause illness in humans emphasizes the importance of proper hygiene practices for personnel working with these animals.