Investigating differences across host species and scales to explain the distribution of the amphibian pathogen Batrachochytrium dendrobatidis

PLoS One. 2014 Sep 15;9(9):e107441. doi: 10.1371/journal.pone.0107441. eCollection 2014.

Abstract

Many pathogens infect more than one host species, and clarifying how these different hosts contribute to pathogen dynamics can facilitate the management of pathogens and can lend insight into the functioning of pathogens in ecosystems. In this study, we investigated a suite of native and non-native amphibian hosts of the pathogen Batrachochytrium dendrobatidis (Bd) across multiple scales to identify potential mechanisms that may drive infection patterns in the Colorado study system. Specifically, we aimed to determine if: 1) amphibian populations vary in Bd infection across the landscape, 2) amphibian community composition predicts infection (e.g., does the presence or abundance of any particular species influence infection in others?), 3) amphibian species vary in their ability to produce infectious zoospores in a laboratory infection, 4) heterogeneity in host ability observed in the laboratory scales to predict patterns of Bd prevalence in the landscape. We found that non-native North American bullfrogs (Lithobates catesbeianus) are widespread and have the highest prevalence of Bd infection relative to the other native species in the landscape. Additionally, infection in some native species appears to be related to the density of sympatric L. catesbeianus populations. At the smaller host scale, we found that L. catesbeianus produces more of the infective zoospore stage relative to some native species, but that this zoospore output does not scale to predict infection in sympatric wild populations of native species. Rather, landscape level infection relates most strongly to density of hosts at a wetland as well as abiotic factors. While non-native L. catesbeianus have high levels of Bd infection in the Colorado Front Range system, we also identified Bd infection in a number of native amphibian populations allopatric with L. catesbeianus, suggesting that multiple host species are important contributors to the dynamics of the Bd pathogen in this landscape.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphibians / microbiology*
  • Animals
  • Chytridiomycota / pathogenicity
  • Colorado
  • Mycoses / pathology*
  • Rana catesbeiana / microbiology

Grants and funding

This work was funded through support from: Boulder County Parks and Open Space, the University of Colorado Department of Ecology and Evolutionary Biology, the University of Colorado Graduate School Beverly Sears Graduate Student Award, the Society of Wetland Scientists, the National Fish and Wildlife Foundation Wildlife Links Program, and NSF grant (DEB: 1146284) to VJM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.