Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis
Journal Publication ResearchOnline@JCUAbstract
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.
Journal
Diseases of Aquatic Organisms
Publication Name
Diseases of Aquatic Organisms
Volume
77
ISBN/ISSN
1616-1580
Edition
N/A
Issue
2
Pages Count
6
Location
N/A
Publisher
Inter-Research
Publisher Url
N/A
Publisher Location
Oldendorf Luhe, Germany
Publish Date
N/A
Url
N/A
Date
N/A
EISSN
N/A
DOI
10.3354/dao01838