Location: Animal Parasitic Diseases LaboratoryTitle: Pathogen exposure and blood chemistry in the Washington population of northern sea otters (Enhydra lutris kenyoni)) Author
Submitted to: Journal of Wildlife Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/3/2013
Publication Date: 10/1/2013
Citation: White, L., Schuler, K., Thomas, N., Webb, J., Saliki, J., Ip, H., Dubey, J.P., Frame, E. 2013. Pathogen exposure and blood chemistry in the Washington population of northern sea otters (Enhydra lutris kenyoni). Journal of Wildlife Diseases. 49:887-899. Interpretive Summary: Sea otters are protected animal species, and by law all dead sea otters are examined at necropsy to determine cause of death.Toxoplasma gondii and Sarcocystis neurona are a single-celled parasites. Toxoplasma causes mental retardation and loss of vision in children, and abortion in livestock. Sarcocystis neurona causes neurological disease in horses and many other species of animals. Both toxoplasma and Sarcocysytis are recognized causes of mortality in marine mammals. In the present study, authors compared mortalities due to different organisms a decade apart. The results will be of interest to biologists, parasitologists, and public health workers.
Technical Abstract: Northern sea otters (Enhydra lutris kenyoni) from Washington State were evaluated in 2011 to determine health status and pathogen exposure. Antibodies to Brucella spp. (10%) and influenza A (23%) were detected for the first time in this population in 2011. Changes in clinical pathology values (serum chemistries), exposure to pathogens, and overall health of the population over the last decade were assessed by comparing 2011 data to data previously collected on this population in 2001-2. Several serum chemistry parameters were different between study years and sexes, but were not clinically significant. The odds of canine distemper virus (CDV) exposure were higher for otters sampled in 2001-2 (80%) compared to 2011 (10%); likelihood of exposure significantly increased with age. Prevalence of exposure to Sarcocystis neurona in Washington sea otters was also higher in 2001-02 (29%) than 2011 (0%), but because testing methods varied between study years the results were not directly comparable. Exposure to Leptospira spp. was only observed in 2001-02. Odds of Toxoplasma gondii exposure were higher for otters sampled in 2011 (97%) than otters in 2001-2 (58%). Substantial levels of domoic acid (n = 2) and saxitoxin (n = 2) were found in urine or fecal samples from animals sampled in 2011. No evidence of calicivirus or Coxiella burnetii exposure in the Washington population of northern sea otters was found in either 2001-02 or 2011. Changes in exposure status from 2001-02 to 2011 suggest that the Washington sea otter population may be dealing with new disease threats (e.g., influenza) while also increasing their susceptibility to diseases that may be highly pathogenic in naïve individuals (e.g., CDV).