Volume 19, Number 3—March 2013
Parallels in Amphibian and Bat Declines from Pathogenic Fungi
|Area of knowledge||B. dendrobatidis
|Current knowledge||Unresolved research questions||Current knowledge||Unresolved research questions|
|Disease emergence||Multiple regions of endemism and 1 widely introduced hypervirulent lineage (7–9)||How and from where did the hypervirulent lineage emerge?||Limited genetic differentiation in North America (10)||How do strains from North America and Europe compare genetically, and is genetic variation greater in Europe, suggesting historic endemism?|
|Possibly endemic to Europe and introduced to North America (6,11,12)
||Can survive in water and soil (13,14)
||Can B. dendrobatidis form desiccation-resistant resting spores? Can B. dendrobatidis survive and reproduce as a saprophytic, nonparasitic form?
||Apparent persistence in soils and on cave walls (12,15)
||How widespread is G. destructans in the environment? Can G. destructans survive and reproduce as a saprophytic, nonparasitic form?
|Biotic reservoirs||Host generalist pathogen of amphibians (4,5)||Can B. dendrobatidis complete its life cycle on other vertebrate hosts?||Host generalist pathogen of bats (6)||Can G. destructans infect or persist on other vertebrates?|
|Can also infect reptiles, nematodes, and waterfowl (16–18)
|Life history and infection risk of the host
||Aquatic, biphasic, tropical amphibian species at greatest risk for chytridiomycosis (19)
||To what extent can life history characteristics of the host predict global patterns of disease-related population decline among amphibian species?
||Bat species that hibernate experience most deaths from WNS (20)
||Are only those species that hibernate susceptible to population decline from WNS? What role does life history of the host play in predicting species declines and extinctions from WNS?
|Host–pathogen interactions||Antimicrobial peptides and antifungal metabolites from skin-associated bacteria contribute to B. dendrobatidis resistance (21)||What is the immune response of B. dendrobatidis–tolerant hosts to infection?||Host immune down-regulation during hibernation probably important to WNS progression (24)||What is the host immune response to G. destructans infection?|
|Susceptible species appear to show little innate or adaptive immune response to B. dendrobatidis infection (22,23)||Does B. dendrobatidis evade the amphibian immune system through activity of secreted proteases?||How does host immunity vary seasonally? What role does immune function play in the observed winter season/hibernation mortality from WNS? Do proteases contribute to pathogenicity of G. destructans?|
*WNS, white-nose syndrome.
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1Both authors contributed equally to this article.
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