title: Linking Ecology and Epidemiology to Understand Predictors of Multi-Host Responses to an Emerging Pathogen, the Amphibian Chytrid Fungus.
abstract: Variation in host responses to pathogens can have cascading effects on populations and communities when some individuals or groups of individuals display disproportionate vulnerability to infection or differ in their competence to transmit infection. The fungal pathogen, Batrachochytrium dendrobatidis (Bd) has been detected in almost 700 different amphibian species and is implicated in numerous global amphibian population declines. Identifying key hosts in the amphibian-Bd system-those who are at greatest risk or who pose the greatest risk for others-is challenging due in part to many extrinsic environmental factors driving spatiotemporal Bd distribution and context-dependent host responses to Bd in the wild. One way to improve predictive risk models and generate testable mechanistic hypotheses about vulnerability is to complement what we know about the spatial epidemiology of Bd with data collected through comparative experimental studies. We used standardized pathogen challenges to quantify amphibian survival and infection trajectories across 20 post-metamorphic North American species raised from eggs. We then incorporated trait-based models to investigate the predictive power of phylogenetic history, habitat use, and ecological and life history traits in explaining responses to Bd. True frogs (Ranidae) displayed the lowest infection intensities, whereas toads (Bufonidae) generally displayed the greatest levels of mortality after Bd exposure. Affiliation with ephemeral aquatic habitat and breadth of habitat use were strong predictors of vulnerability to and intensity of infection and several other traits including body size, lifespan, age at sexual maturity, and geographic range also appeared in top models explaining host responses to Bd. Several of the species examined are highly understudied with respect to Bd such that this study represents the first experimental susceptibility data. Combining insights gained from experimental studies with observations of landscape-level disease prevalence may help explain current and predict future pathogen dynamics in the Bd system.
authors.affiliation: Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America.
authors.forename: Stephanie S
authors.identifier: 0000-0003-4829-6915
authors.initials: SS
authors.lastname: Gervasi
authors.affiliation: Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Stephens
authors.affiliation: Biological Sciences Department, Binghamton University, Binghamton, New York, United States of America.
authors.forename: Jessica
authors.initials: J
authors.lastname: Hua
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Searle
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Gisselle Yang
authors.initials: GY
authors.lastname: Xie
authors.affiliation: Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Jenny
authors.initials: J
authors.lastname: Urbina
authors.affiliation: United States Forest Service, Pacific Northwest Research Station, Corvallis, Oregon, United States of America.
authors.forename: Deanna H
authors.initials: DH
authors.lastname: Olson
authors.affiliation: Biology Department, Gonzaga University, Spokane, Washington, United States of America.
authors.forename: Betsy A
authors.initials: BA
authors.lastname: Bancroft
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Virginia
authors.initials: V
authors.lastname: Weis
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America.
authors.forename: John I
authors.initials: JI
authors.lastname: Hammond
authors.affiliation: Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, United States of America.
authors.forename: Rick A
authors.initials: RA
authors.lastname: Relyea
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Blaustein
mesh_terms: D000663:Amphibians / Q000382:microbiology*; D000818:Animals; D002025:Bufonidae / Q000382:microbiology; D008411:Chytridiomycota / Q000472:pathogenicity*; D021821:Communicable Diseases, Emerging / Q000453:epidemiology*; D004463:Ecology; D017753:Ecosystem; D054884:Host-Pathogen Interactions; D009181:Mycoses / Q000382:microbiology*; D010802:Phylogeny; D011898:Ranidae / Q000382:microbiology