Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis

Diseases of Aquatic Organisms

Speare Rebecca Webb Jeffrey Warner Donna Rudd Ruth Campbell Lee F. Skerratt¹  Jamie Voyles, Lee Berger Sam Young Rick¹ 

关键词: Amphibian declines;    Chytridiomycosis;    Batrachochytrium dendrobatidis;    Pathogenesis;    Mortality;    Osmoregulation;   

DOI  :  10.3354/dao01838

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

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.

【 授权许可】

Unknown