Necropsy Findings and Environmental Contaminants in Common Loons from New York

Stone, Ward B.; Okoniewski, Joseph C.

doi:10.7589/0090-3558-37.1.178

Cited by 26 publications

(14 citation statements)

References 18 publications

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“…Loons are also exposed to other environmental contaminants including lead (Pb), in the form of Pb fishing sinkers and jigs that they occasionally ingest (Pokras and Chafel, 1992;Scheuhammer and Norris, 1996), and selenium (Se) and organochlorine compounds (Scheuhammer et al, 1998a;Stone and Okoniewski, 2001) that bioaccumulate in their fish prey. We determined the exposure of breeding loons to these other contaminants as well.…”

Section: Introductionmentioning

confidence: 99%

Mercury and other Contaminants in Common Loons Breeding in Atlantic Canada

2005

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Common loons (Gavia immer) were studied to assess the biomagnification of persistent contaminants in lake ecosystems in Atlantic Canada. Forty-two breeding adults and 20 juvenile loons were captured in August, 1995-1997 on lakes in four areas of southern New Brunswick (Lepreau and Fundy National Park) and Nova Scotia (Halifax and Kejimkujik National Park). Blood samples were collected for analysis of mercury, methylmercury, lead, and selenium. Plasma samples from adult loons were analyzed for PCB congeners and organochlorine pesticides. Secondary flight feathers were collected from adult loons for mercury analysis. Kejimkujik loons had significantly higher geometric mean concentrations of mercury in blood (adults: 5.5 microg/g, wet wt) and feathers (adults: 15 microg/g, fresh wt), and higher levels of PCBs, DDE, oxychlordane, trans-nonachlor, mirex and hexachlorobenzene than loons at Halifax or Lepreau. Blood selenium levels were lowest in Kejimkujik loons. Selenium and mercury concentrations were negatively related in blood of adults across all sites. Adult males had higher concentrations of mercury in blood and feathers and PCBs, DDE, and oxychlordane in plasma, and lower levels of selenium in blood, than adult females. Juvenile loons had lower blood mercury and selenium concentrations than adults. Several contaminants showed significant inter-lake variation within the study sites. Mean blood mercury concentrations in Kejimkujik loons are the highest found in breeding common loons across North America. Of adult loons at Kejimkujik, 92% had blood mercury levels > 4 microg/g (wet wt), which have been associated with impaired reproduction, elevated corticosterone levels, asymmetry in plumage development, and altered breeding behavior in loons there and elsewhere.

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Section: Introductionmentioning

confidence: 99%

Mercury and other Contaminants in Common Loons Breeding in Atlantic Canada

2005

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“…They overwinter in large numbers in the Atlantic and Gulf waters of Florida, where each year numerous loons are found dead (White et al, 1976;Forrester et al, 1997). Several mortality events have been investigated and the most common causes of death included respiratory aspergillosis, trauma, mercury toxicosis, lead toxicosis, oiling, and an emaciation syndrome of unknown etiology (White et al, 1976;Locke et al, 1982;Brand et al, 1988;Forrester et al, 1997;Daoust et al, 1998;Stone and Okoniewski, 2001;Sidor et al, 2003). To our knowledge, no herpesviral pathogens of Gaviiformes have been documented.…”

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confidence: 99%

“…being the infectious agent most commonly documented (White et al, 1976;Forrester et al, 1997;Daoust et al, 1998;Stone and Okoniewski, 2001;Sidor et al, 2003). The only viral pathogen reported from a loon is avian paramyxovirus type 1 (Alexander et al, 1987).…”

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confidence: 99%

Detection and Phylogenetic Characterization of a Novel Herpesvirus from the Trachea of Two Stranded Common Loons (Gavia immer)

Quesada

Heard

Aitken‐Palmer

et al. 2011

Journal of Wildlife Diseases

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ABSTRACT:Two wild adult Common Loons (Gavia immer) were evaluated after being found stranded in mainland north-central Florida on separate occasions. On the basis of upper airway endoscopic and cytologic findings, we diagnosed severe ulcerative tracheitis antemortem in one of the birds while more subtle lesions were observed in the other. A novel herpesvirus was detected in antemortem tracheal samples using nested consensus PCR amplification of the polymerase gene and sequencing. Despite prolonged intensive medical care, the bird with severe lesions failed to improve and was euthanized 9 days after endoscopy. No viral inclusions were evident histologically in the lesions. However, an undulating tracheal mucosa in a ''mountain ridge'' pattern, resulting from epithelial regeneration and hyperplasia, was present, as is seen in the late stages of infectious laryngotracheitis in chickens. The second bird recovered and was released. The genetic distance between this and other characterized herpesviruses supports placement of this virus as a novel species, referred to as Gaviid herpesvirus 1 (GavHV1). Phylogenetically, GavHV1 clusters within the genus Iltovirus. The relationship between the observed lesions and the virus remains to be demonstrated.

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“…In juvenile common loons (Gavia immer), MeHg suppressed cell-mediated and antibody responsiveness at environmentally relevant exposure concentrations equivalent to 0.4 mg/kg MeHg in the diet [9]; atrophy and lymphoid depletion of immune system organs have been reported in juvenile double-crested cormorants (Phalacrocorax autitus) and great egrets (Ardea alba) [10,11]; and MeHg has been directly linked to chronic multiple disease occurrences in free-living aquatic avian species [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Toxic effects of dietary methylmercury on immune system development in nestling American kestrels (Falco sparverius)

Fallacara

Halbrook

French

2011

Enviro Toxic and Chemistry

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This study evaluated the effects of dietary methylmercury (MeHg) on immune system development in captive-reared nestling American kestrels (Falco sparverius) to determine whether T cell-mediated and antibody-mediated adaptive immunity are targets for MeHg toxicity at environmentally relevant concentrations. Nestlings received various diets, including 0 (control), 0.6, and 3.9 µg/g (dry wt) MeHg for up to 18 d posthatch. Immunotoxicity endpoints included cell-mediated immunity (CMI) using the phytohemagglutinin (PHA) skin-swelling assay and antibody-mediated immune response via the sheep red blood cell (SRBC) hemagglutination assay. T cell- and B cell-dependent histological parameters in the spleen, thymus, and bursa of Fabricius were correlated with the functional assays. For nestlings in the 0.6 and 3.9 µg/g MeHg groups, CMI was suppressed by 73 and 62%, respectively, at 11 d of age. Results of this functional assay were correlated with T cell-dependent components of the spleen and thymus. Dose-dependent lymphoid depletion in spleen tissue directly affected the proliferation of T-lymphocyte populations, insofar as lower stimulation indexes from the PHA assay occurred in nestlings with lower proportions of splenic white pulp and higher THg concentrations. Nestlings in the 3.9 µg/g group also exhibited lymphoid depletion and a lack of macrophage activity in the thymus. Methylmercury did not have a noticeable effect on antibody-mediated immune function or B cell-dependent histological correlates. We conclude that T cell-mediated immunosuppression is the primary target of MeHg toward adaptive immunity in developing kestrels. This study provides evidence that environmentally relevant concentrations of MeHg may compromise immunocompetence in a developing terrestrial predator and raises concern regarding the long-term health effects of kestrels that were exposed to dietary MeHg during early avian development.

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Necropsy Findings and Environmental Contaminants in Common Loons from New York

Cited by 26 publications

References 18 publications

Mercury and other Contaminants in Common Loons Breeding in Atlantic Canada

Mercury and other Contaminants in Common Loons Breeding in Atlantic Canada

Detection and Phylogenetic Characterization of a Novel Herpesvirus from the Trachea of Two Stranded Common Loons (Gavia immer)

Toxic effects of dietary methylmercury on immune system development in nestling American kestrels (Falco sparverius)

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