DAO 77:113-118 (2007)  -  DOI: https://doi.org/10.3354/dao01838

Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis

Jamie Voyles1,*, Lee Berger1, Sam Young1, Rick Speare1, Rebecca Webb1, Jeffrey Warner2, Donna Rudd2, Ruth Campbell1, Lee F. Skerratt2

1Amphibian Disease Ecology Group, School of Public Health, Tropical Medicine and Rehabilitation Sciences, and 2Amphibian Disease Ecology Group, School of Veterinary and Biomedical Sciences, James Cook University, Townsville, Queensland 4811, Australia

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.


KEY WORDS: Amphibian declines · Chytridiomycosis · Batrachochytrium dendrobatidis · Pathogenesis · Mortality · Osmoregulation


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Cite this article as: Voyles J, Berger L, Young S, Speare R and others (2007) Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis. Dis Aquat Org 77:113-118. https://doi.org/10.3354/dao01838

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