Infection with Brucella spp., long known as a cause of abortion, infertility, and reproductive loss in domestic livestock, has increasingly been documented in marine mammals over the past two decades. We report molecular evidence of Brucella infection in Asian sea otters (Enhydra lutris lutris). Brucella DNA was detected in 3 of 78 (4%) rectal swab samples collected between 2004 and 2006 on Bering Island, Russia. These 78 animals had previously been documented to have a Brucella seroprevalence of 28%, markedly higher than the prevalence documented in sea otters (Enhydra lutris) in North America. All of the DNA sequences amplified were identical to one or more previously isolated Brucella spp. including strains from both terrestrial and marine hosts. Phylogenetic analysis of this sequence suggested that one animal was shedding Brucella spp. DNA with a sequence matching a Brucella abortus strain, whereas two animals yielded a sequence matching a group of strains including isolates classified as Brucella pinnipedialis and Brucella melitensis. Our results highlight the diversity of Brucella spp. within a single sea otter population.
University of California, Davis, Wildlife Health Center, Orcas Island Office, School of Veterinary Medicine, University of California, Davis, 1016 Deer Harbor Road, Eastsound, Washington 98245, USA. firstname.lastname@example.org
The investigation of diseases of free-ranging river otters (Lontra canadensis) is a primary conservation priority for this species; however, very little is known about diseases of river otters that forage in marine environments. To identify and better understand pathogens that could be important to marine-foraging river otters, other wildlife species, domestic animals, and humans and to determine if proximity to human population could be a factor in disease exposure, serum samples from 55 free-ranging marine-foraging river otters were tested for antibodies to selected pathogens. Thirty-five animals were captured in Prince William Sound, Alaska (USA), an area of low human density, and 20 were captured in the San Juan Islands, Washington State (USA), an area characterized by higher human density. Of 40 river otters tested by indirect immunofluorescent antibody test, 17.5% were seropositive (titer > or =320) for Toxoplasma gondii. All positive animals came from Washington. Of 35 river otters tested for antibodies to Leptospira interrogans using the microscopic agglutination test, 10 of 20 (50%) from Washington were seropositive (titer > or =200). None of the 15 tested animals from Alaska were positive. Antibodies to Neospora caninum (n=40), Sarcocystis neurona (n=40), Brucella abortus (n=55), avian influenza (n=40), canine distemper virus (n=55), phocine distemper virus (n=55), dolphin morbillivirus (n=55), porpoise morbillivirus (n=55), and Aleutian disease parvovirus (n=46) were not detected. Identifying exposure to T. gondii and L. interrogans in otters from Washington State but not in otters from Alaska suggests that living proximal to higher human density and its associated agricultural activities, domestic animals, and rodent populations could enhance river otter exposure to these pathogens.
Environmental samples collected along the coastline and from the interior of Alaska were examined for the presence of Clostridium botulinum. Clostridium botulinum type E was detected in soils from 5 of 12 beaches; in 7 of 115 non-coastal soil samples; in sediments from six of eight locales; in gills of salmon from two fishing areas; and in the feces of 1 of 44 colonic samples from marine mammals. The basic biochemical characteristics of the isolates were determined. Tube tests for demonstrating gelatin liquefaction proved insensitive with these strains, whereas a plate test detected gelatinase in all isolates. The presence of multiple nidi and the continual discharge of organic materials into the environment may contribute to the perpetuation of botulinum spores by which foods prepared form marine animals become contaminated. An emphasis should be placed upon the need for measures to reduce environmental contamination, to reduce contamination during food preparation, and to alert continually the population of the hazard wherever botulism is endemic.
From: Fortuine, Robert et al. 1993. The Health of the Inuit of North America: A Bibliography from the Earliest Times through 1990. University of Alaska Anchorage. Citation number 1847.
: Streptococcus phocae is a pathogen of marine mammals, although its pathogenicity remains poorly understood. Recovery of this bacterium from asymptomatic carriers suggests that it is an opportunistic pathogen. We investigated the role of S. phocae in naturally occurring disease and its significance as a pathogen based on postmortem investigations. Between 2007 and 2012, 1,696 whole carcasses, tissue samples, or both were submitted from the northeastern Pacific and Arctic Canada for diagnostic testing. Streptococcus phocae was cultured from phocids ( n=66), otariids ( n=12), harbor porpoises ( Phocoena phocoena; n=5), and sea otters ( Enhydra lutris; n=2). Pathologic manifestations of S. phocae-associated disease included localized, as well as systemic, inflammatory lesions with common findings of suppurative bronchopneumonia ( n=17) and bacteremia ( n=27). Lung lesions were frequently culture-positive for S. phocae, suggesting commensal colonization of the oropharynx with subsequent opportunistic infection of the respiratory tract during tissue injury, coinfection, immunosuppression, or other debilitating conditions. The presence of a positive spleen culture, and interpretations at necropsy and histopathology, were used to determine the presence of S. phocae bacteremia. Less frequent lesions that were culture positive for S. phocae included abscesses ( n=9), meningitis ( n=7), and cellulitis ( n=1). The majority of cases with S. phocae lesions featured pre-existing conditions that presumably contributed to some degree of debilitation or immunosuppression, including emaciation ( n=29), liver mercury accumulation ( n=29), trauma ( n=22), severe pulmonary or cardiovascular nematodiasis ( n=9), concurrent bacterial or viral infections ( n=8), or sarcocystosis ( n=6). These findings suggest that S. phocae could be characterized as an opportunistic pathogen, associated with debilitating conditions in stranded and rehabilitating marine mammals. Wildlife investigators can use these results to draw more definitive conclusions regarding positive S. phocae cultures during postmortem studies in marine mammals.