title: Surveillance for zoonotic and selected pathogens in harbor seals Phoca vitulina from central California.
abstract: The infection status of harbor seals Phoca vitulina in central California, USA, was evaluated through broad surveillance for pathogens in stranded and wild-caught animals from 2001 to 2008, with most samples collected in 2007 and 2008. Stranded animals from Mendocino County to San Luis Obispo County were sampled at a rehabilitation facility: The Marine Mammal Center (TMMC, n = 175); wild-caught animals were sampled at 2 locations: San Francisco Bay (SF, n = 78) and Tomales Bay (TB, n = 97), that differed in degree of urbanization. Low prevalences of Salmonella, Campylobacter, Giardia, and Cryptosporidium were detected in the feces of stranded and wild-caught seals. Clostridium perfringens and Escherichia coli were more prevalent in the feces of stranded (58% [78 out of 135] and 76% [102 out of 135]) than wild-caught (42% [45 out of 106] and 66% [68 out of 106]) seals, whereas Vibrio spp. were 16 times more likely to be cultured from the feces of seals from SF than TB or TMMC (p < 0.005). Brucella DNA was detected in 3.4% of dead stranded harbor seals (2 out of 58). Type A influenza was isolated from feces of 1 out of 96 wild-caught seals. Exposure to Toxoplasma gondii, Sarcocystis neurona, and type A influenza was only detected in the wild-caught harbor seals (post-weaning age classes), whereas antibody titers to Leptospira spp. were detected in stranded and wild-caught seals. No stranded (n = 109) or wild-caught (n = 217) harbor seals had antibodies to phocine distemper virus, although a single low titer to canine distemper virus was detected. These results highlight the role of harbor seals as sentinel species for zoonotic and terrestrial pathogens in the marine environment.
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews KY16 8LB, UK.
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Greig
authors.forename: Frances M D
authors.initials: FM
authors.lastname: Gulland
authors.forename: Woutrina A
authors.initials: WA
authors.lastname: Smith
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Conrad
authors.forename: Cara L
authors.initials: CL
authors.lastname: Field
authors.forename: Michelle
authors.initials: M
authors.lastname: Fleetwood
authors.forename: James T
authors.initials: JT
authors.lastname: Harvey
authors.forename: Hon S
authors.initials: HS
authors.lastname: Ip
authors.forename: Spencer
authors.initials: S
authors.lastname: Jang
authors.forename: Andrea
authors.initials: A
authors.lastname: Packham
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wheeler
authors.forename: Ailsa J
authors.initials: AJ
authors.lastname: Hall
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D002140:California / Q000453:epidemiology; D005243:Feces / Q000382:microbiology / Q000469:parasitology; D046049:Phoca; D011159:Population Surveillance; D011529:Protozoan Infections, Animal / Q000453:epidemiology / Q000469:parasitology*; D014777:Virus Diseases / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D015047:Zoonoses