Chemical and biological pollution contribute to the immunological profiles of free-ranging harbor seals

Polychlorinated biphenyls and other persistent organic pollutants have been associated with immunotoxicity and outbreaks of (infectious) disease in marine mammals by rendering them vulnerable to infection by pathogens such as viruses and bacteria. In an immunotoxicological study of free‐ranging harb...

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Bibliographic Details
Published in:Environmental toxicology and chemistry 2006-12, Vol.25 (12), p.3110-3117
Main Authors: Mos, Lizzy, Morsey, Brenda, Jeffries, Steven J., Yunker, Mark B., Raverty, Stephen, Guise, Sylvain De, Ross, Peter S.
Format: Article
Language:English
Subjects:
Animal, plant and microbial ecology
Animals
Animals, Wild - blood
Animals, Wild - immunology
Applied ecology
Biological and medical sciences
Biological pollution
British Columbia
E coli
Ecotoxicology, biological effects of pollution
Fundamental and applied biological sciences. Psychology
General aspects
Harbor seals
Immune system
Immunotoxicity
Mammalia
Marine
Marine mammals
Phoca - blood
Phoca - immunology
Phoca vitulina
Polychlorinated biphenyls
Polychlorinated Biphenyls - analysis
Polychlorinated Biphenyls - toxicity
Studies
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
Washington
Water Pollutants - analysis
Water Pollutants - toxicity
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Summary:Polychlorinated biphenyls and other persistent organic pollutants have been associated with immunotoxicity and outbreaks of (infectious) disease in marine mammals by rendering them vulnerable to infection by pathogens such as viruses and bacteria. In an immunotoxicological study of free‐ranging harbor seals (Phoca vitulina), we obtained samples of blood and blubber from seal pups that were live‐captured from two remote and two near‐urban sites in British Columbia, Canada, and Washington state, USA. Using these samples, we quantified hematology, innate immune function, adaptive immune function, and polychlorinated biphenyl accumulation. While controlling for confounding factors (age, sex, and condition), univariate correlations between phagocytosis (r2 = 0.30, p = 0.002), respiratory burst (r2 = 0.45, p = 0.000), T‐lymphocyte function (r2 = 0.16, p = 0.028), lymphocyte signaling (r2 = 0.17, p = 0.025), and lymphocyte counts (r2 = 0.29, p = 0.002), and polychlorinated biphenyl concentrations suggested chemical‐associated immunotoxicity. Principal component analysis of immunological endpoints provided additional evidence of immunotoxic effects in seals. However, principal component analysis also identified a noncontaminant‐related factor by distinguishing between seals inhabiting urban versus remote sites, with results being consistent with increased pathogen exposure. Elevated fecal coliform concentrations in water, and observations of terrestrial spill‐over pathogens in local seals, further support the notion of biological pollution at these sites. Although our study highlights the role that environmental contaminants might play in rendering marine mammal populations vulnerable to disease through immunotoxicity, it also suggests that biological pollution represents an emerging conservation concern.
ISSN:0730-7268
1552-8618
DOI:10.1897/06-027R.1