title: Correlates of virulence in a frog-killing fungal pathogen: evidence from a California amphibian decline.
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.
authors.affiliation: Department of Biology, University of California, Riverside, CA, USA.
authors.forename: Jonah
authors.initials: J
authors.lastname: Piovia-Scott
authors.affiliation: Pacific Southwest Research Station, United States Forest Service, Arcata, CA, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Pope
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, Davis, CA, USA.
authors.forename: S Joy
authors.initials: SJ
authors.lastname: Worth
authors.affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.
authors.forename: Erica Bree
authors.initials: EB
authors.lastname: Rosenblum
authors.affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Poorten
authors.affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.
authors.forename: Jeanine
authors.initials: J
authors.lastname: Refsnider
authors.affiliation: 1] Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA [2] Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA [3] Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
authors.forename: Louise A
authors.initials: LA
authors.lastname: Rollins-Smith
authors.affiliation: 1] Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA [2] Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Reinert
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
authors.forename: Heather L
authors.initials: HL
authors.lastname: Wells
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, Davis, CA, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Rejmanek
authors.affiliation: Department of Entomology, University of California, Davis, CA, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Lawler
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, Davis, CA, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Foley
mesh_terms: D000818:Animals; D002140:California / Q000453:epidemiology; D008411:Chytridiomycota / Q000472:pathogenicity*; D009181:Mycoses / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D011157:Population Dynamics; D011898:Ranidae / Q000382:microbiology*; D014774:Virulence