Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) has caused declines and extinctions in amphibians worldwide, and there is increasing evidence that some strains of this pathogen are more virulent than others. While a number of putative virulence factors have been identified, few studies link these factors to specific epizootic events. We documented a dramatic decline in juvenile frogs in a Bd-infected population of Cascades frogs (Rana cascadae) in the mountains of northern California and used a laboratory experiment to show that Bd isolated in the midst of this decline induced higher mortality than Bd isolated from a more stable population of the same species of frog. This highly virulent Bd isolate was more toxic to immune cells and attained higher density in liquid culture than comparable isolates. Genomic analyses revealed that this isolate is nested within the global panzootic lineage and exhibited unusual genomic patterns, including increased copy numbers of many chromosomal segments. This study integrates data from multiple sources to suggest specific phenotypic and genomic characteristics of the pathogen that may be linked to disease-related declines.
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Acknowledgements
Monty Larson, Kevin Aceituno and Cathy Johnson and many others helped in field data collection; Carlos Davidson and Daniella Reagan helped with the amphibian experiment. This research was supported by grants from the California Department of Fish and Wildlife, the United States Fish and Wildlife Service, Lassen National Forest and the National Science Foundation (IOS-1121758 and IOS-12244804).
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Piovia-Scott, J., Pope, K., Joy Worth, S. et al. Correlates of virulence in a frog-killing fungal pathogen: evidence from a California amphibian decline. ISME J 9, 1570–1578 (2015). https://doi.org/10.1038/ismej.2014.241
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DOI: https://doi.org/10.1038/ismej.2014.241
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