PREVALENCE, PATHOLOGY, AND RISK FACTORS ASSOCIATED WITHSTREPTOCOCCUS PHOCAEINFECTION IN SOUTHERN SEA OTTERS (ENHYDRA LUTRIS NEREIS), 2004–10

Abstract

Recent studies have implicated beta-hemolytic streptococci as opportunistic pathogens of marine mammals, including southern sea otters (Enhydra lutris nereis), but little is known about their prevalence or pathophysiology. Herein, we focus on risk factors for sea otter infection by a single beta-hemolytic streptococcal species, Streptococcus phocae. Streptococcus phocae was first identified as a marine mammal pathogen in 1994, and the first report in southern sea otters was in 2009. Its broad host range encompasses fish, pinnipeds, cetaceans, and mustelids, with S. phocae now recognized as an important pathogen of marine species worldwide. We assessed risk factors and lesion patterns for S. phocae infection in southern sea otters. Using archival necropsy data, S. phocae prevalence was 40.5% in fresh dead otters examined 2004-10. Skin trauma of any type was identified as a significant risk factor for S. phocae infection. The risk of infection was similar regardless of the cause and relative severity of skin trauma, including mating or fight wounds, shark bite, and anthropogenic trauma. Streptococcus phocae-infected sea otters were also more likely to present with abscesses or bacterial septicemia. Our findings highlight the importance of S. phocae as an opportunistic pathogen of sea otters and suggest that the most likely portal of entry is damaged skin. Even tiny skin breaks appear to facilitate bacterial colonization, invasion, abscess formation, and systemic spread. Our data provide important insights for management and care of marine species.

Molecular characterization and prevalence of Halarachne halichoeri in threatened southern sea otters (Enhydra lutris nereis)

“…Heavy burdens of respiratory mites were recently implicated in facilitating a lethal β-hemolytic Streptococci -associated outbreak in fur seal pups ( Seguel et al., 2018 ). β-hemolytic Streptococci are important southern sea otter pathogens ( Imai et al., 2009 ; Bartlett et al., 2016 ), and it is possible that halarachnid mites may spread other pathogens in sea otters. Future research should focus on further clarifying halarachnid mite ecology, improving diagnostic methods, validating treatment options for sea otters under human care, and assessing the potential for these mites to spread pathogens between phocids and sea otters, or among sympatric sea otters.…”

Causes of mortality and morbidity in free-ranging mustelids in Switzerland: necropsy data from over 50 years of general health surveillance

“…Bite wounds were repeatedly observed both in martens and badgers and identified as the primary cause of skin lesions such as post-scarring alopecia. Bite wounds are common in mustelids [ 83 , 101 – 103 ] and may be related to intraspecific fights, especially in martens. In mustelids there is a correlation between the degree of intra-sexual territoriality (associated with aggressive behavior) and the degree of body elongation, sexual dimorphism and degree of carnivorous behavior [ 104 ], three characteristics which are more pronounced in martens than in badgers.…”

Mustelids

“…In contrast, S. phocae and related beta-hemolytic streptococci has been identified as major opportunistic pathogen of Southern sea otters (Bartlett et al, 2016). Lesions include sepsis and abscess formation, and may also include meningoencephalitis ( Fig.…”