Biology and Diseases of Amphibians

Anver, Miriam R.; Pond, Cynthia L.

doi:10.1016/b978-0-12-263620-2.50020-3

Cited by 20 publications

(20 citation statements)

References 62 publications

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“…Previous studies indicated that parasites in the blood system seemed to be common in salamanders and amphibians [8,23,25,26]. In this study, none of the eastern hellbenders tested positive for blood parasites, whereas approximately 33% of the Ozark hellbenders tested positive.…”

Section: Discussioncontrasting

confidence: 55%

Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis)

Huang

Briggler

et al. 2010

Environmental Toxicology and Chemistry

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Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) from seven rivers in Missouri, USA, were collected to investigate essential information on hematology, parasites, and plasma chemistry and levels of select heavy metals (Hg, Pb, Cd, Cr, and Co) in the animals' blood. The body masses of Ozark hellbenders were much smaller than those of eastern hellbenders. Blood parasites were detected in Ozark hellbenders, but not eastern hellbenders. The higher frequency in occurrence of eosinophils in Ozark hellbenders (8.8-16.8%) than in eastern hellbenders (highest at 6.6%) might result from the infection of parasites. Seven of the 18 hematology and plasma parameters (hematocrit, basophils, eosinophils, K, P, Ca, and chloride) showed significant differences between subspecies. The blood levels of heavy metals Co, Hg, and Pb differed significantly between subspecies. Ozark hellbenders had higher blood levels of Co (p<0.001), while blood levels of Hg and Pb were higher in eastern hellbenders. The levels of chromium (Cr) and cadmium (Cd) were not different between subspecies and among rivers. The eastern hellbenders at Niangua River and the Ozark hellbenders at the North Fork of the White River had lower Hg levels compared to eastern and Ozark hellbenders at other sites. All together, our findings provide important baseline information for managing this endangered species.

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Section: Discussioncontrasting

confidence: 55%

Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis)

Huang

Briggler

et al. 2010

Environmental Toxicology and Chemistry

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“…While M. marinum can cause caseous necrosis in humans, goldfish, and the toads Xenopus laevis and Xenopus borealis (9,28,57,58), this does not appear to be a feature of R. pipiens granulomas. This is likely due to differences in the host response to infection-many frog species fail to undergo caseation, a phenomenon for which a pathological basis is not clear (7). Despite the absence of obvious caseous necrosis, we thought it possible that the organisms contained within granulomas resided in an extracellular niche and that this might explain why some M. marinum genes are active only in granulomas and not in cultured macrophages (45).…”

Section: Discussionmentioning

confidence: 95%

Dynamic Nature of Host-Pathogen Interactions inMycobacterium marinumGranulomas

Bouley¹,

Ghori

Mercer³

et al. 2001

Infect Immun

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Mycobacterium marinum causes long-term subclinical granulomatous infection in immunocompetent leopard frogs (Rana pipiens). These granulomas, organized collections of activated macrophages, share many morphological features with persistent human tuberculous infection. We examined organs of frogs with chronic M. marinum infection using transmission electron microscopy in conjunction with immunohistochemistry and acid phosphatase cytochemistry to better define the bacterium-host interplay during persistent infection. Bacteria were always found within macrophage phagosomes. These phagosomes were often fused to lysosomes, in sharp contrast to those formed during in vitro infection of J774 macrophage-like cells by M. marinum. The infected macrophages in frog granulomas showed various levels of activation, as evidenced by morphological changes, including epithelioid transformation, recent phagocytic events, phagolysosomal fusion, and disintegration of bacteria. Our results demonstrate that even long-term granulomas are dynamic environments with regard to the level of host cell activation and bacterial turnover and suggest a continuum between constantly replicating bacteria and phagocytic killing that maintains relatively constant bacterial numbers despite an established immune response. Infection with a mutant bacterial strain with a reduced capacity for intracellular replication shifted the balance, leading to a greatly reduced bacterial burden and inflammatory foci that differed from typical granulomas.

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“…The underlying mechanism causing decreased Bd prevalence in the fall remains unclear. It is possible that warmer summer temperatures allow for maximum immune activity to fight Bd infection (Anver & Pond 1984) and/or that frogs may exhibit thermoregulatory basking behavior, which could reduce Bd infection (Richards-Zawacki 2010). While prevalence decreased in the fall, frogs that were infected in the fall had higher infection intensities than in other seasons.…”

Section: Discussionmentioning

confidence: 99%

Batrachochytrium dendrobatidis infection dynamics in the Columbia spotted frog Rana luteiventris in north Idaho, USA

Russell¹,

Goldberg²,

Waits³

et al. 2010

Dis. Aquat. Org.

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The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) is contributing to amphibian declines worldwide. Temperature plays an important role in both pathogen growth and host immune function, but little is known about seasonal dynamics of Bd infection in north temperate regions. Our objective was to increase understanding of Bd disease ecology by investigating patterns of Bd infection of Columbia spotted frogs Rana luteiventris across seasons, age classes, and sexes in north Idaho, USA. We collected skin swabs from 223 R. luteiventris in spring, summer, and fall 2009 at 7 ponds in the Palouse region and quantified Bd zoospores for each sample using quantitative PCR. Across seasons, Bd prevalence of adults was higher in summer than in spring or fall, suggesting that individuals may be clearing low-level infections over the summer. Among age classes, all but one late stage tadpole (Gosner stage 43-45) tested negative for Bd. Conversely, 100% of metamorphs tested positive for Bd and had the highest Bd loads of all age classes, suggesting they may be the most vulnerable age class. Adult R. luteiventris had high infection prevalence (> 60%) in all seasons, indicating that Bd infection is maintained within populations and that adults likely serve as disease reservoirs across seasons. Among adults, we also found weak evidence for females having higher infection prevalence than males. Further laboratory and field studies are needed to determine whether there are individual and population impacts from Bd on R. luteiventris and other amphibians in north Idaho. KEY WORDS:Amphibian declines · Batrachochytrium dendrobatidis · Chytrid · Idaho · Rana luteiventris Resale or republication not permitted without written consent of the publisherContribution to DAO Special 4 'Chytridiomycosis: an emerging disease'

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Biology and Diseases of Amphibians

Cited by 20 publications

References 62 publications

Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis)

Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis)

Dynamic Nature of Host-Pathogen Interactions inMycobacterium marinumGranulomas

Batrachochytrium dendrobatidis infection dynamics in the Columbia spotted frog Rana luteiventris in north Idaho, USA

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