Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis

Voyles, Jamie, Berger, Lee, Young, Sam, Speare, Rick, Webb, Rebecca, Warner, Jeffrey, Rudd, Donna, Campbell, Ruth, and Skerratt, Lee F. (2007) Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis. Diseases of Aquatic Organisms, 77 (2). pp. 113-118.

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Abstract

Mounting evidence implicates the disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, in global amphibian declines and extinctions. While the virulence of this disease has been clearly demonstrated, there is, as yet, no mechanistic explanation for how B. dendrobatidis kills amphibians. To investigate the pathology of chytridiomycosis, blood samples were collected from uninfected, aclinically infected and clinically diseased amphibians and analyzed for a wide range of biochemical and hematological parameters. Here, we show that green tree frogs Litoria caerulea with severe chytridiomycosis had reduced plasma osmolality, sodium, potassium, magnesium and chloride concentrations. Stable plasma albumin, hematocrit and urea levels indicated that hydration status was unaffected, signifying depletion of electrolytes from circulation rather than dilution due to increased water uptake. We suggest that B. dendrobatidis kills amphibians by disrupting normal epidermal functioning, leading to osmotic imbalance through loss of electrolytes. Determining how B. dendrobatidis kills amphibians is fundamental to understanding the host– pathogen relationship and thus the population declines attributed to B. dendrobatidis. Understanding the mechanisms of mortality may also explain interspecific variation in susceptibility to chytridiomycosis.

Item ID: 2608
Item Type: Article (Refereed Research - C1)
Keywords: amphibian declines; chytridiomycosis; Batrachochytrium dendrobatidis; pathogenesis; mortality; osmoregulation
ISSN: 1616-1580
Date Deposited: 24 Jul 2009 04:18
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070709 Veterinary Pathology @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 100%
Citation Count from Web of Science Web of Science 75
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Last 12 Months: 43
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