Presence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) in rainwater suggests aerial dispersal is possible
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Global spread of the pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) may involve dispersal mechanisms not previously explored. Weather systems accompanied by strong wind and rainfall have been known to assist the dispersal of microbes pathogenic to plants and animals, and we considered a similar phenomenon might occur with Bd. We investigated this concept by sampling rainwater from 20 precipitation events for the presence of Bd in Cusuco National Park, Honduras: a site where high Bd prevalence was previously detected in stream-associated amphibians. Quantitative PCR analysis confirmed the presence of Bd in rainwater in one (5 %) of the weather events sampled, although viability cannot be ascertained from molecular presence alone. The source of the Bd and distance that the contaminated rainwater traveled could not be determined; however, this collection site was located approximately 600 m from the nearest observed perennial river by straight-line aerial distance. Although our results suggest atmospheric Bd dispersal is uncommon and unpredictable, even occasional short-distance aerial transport could considerably expand the taxonomic diversity of amphibians vulnerable to exposure and at risk of decline, including terrestrial and arboreal species that are not associated with permanent water bodies.
KeywordsAmphibian chytrid fungus Batrachochytrium dendrobatidis Chytridiomycosis Dispersal Atmospheric Rain
This research was supported, in part, by the Mohamed Bin Zayed Species Conservation Fund, Rufford Small Grants for Nature Conservation, Chicago Zoological Society/Chicago Board of Trade Endangered Species Fund, and the Columbus Zoo and Aquarium. Sampling was performed in Cusuco National Park with permission from the Instituto Nacional de Conservacion y Desarollo Forestal Areas Protegidas y Vida Silvestre (ICF) as part of the long-term biodiversity monitoring program performed by Operation Wallacea. We thank Operation Wallacea for orchestrating fieldwork logistics and are grateful for the many volunteers and local guides who assisted with sample collection. We also thank D. Calhoun, K. Richards-Hrdlicka, J. Kirshtein, and B. Scheele for their helpful advice on field methods and earlier manuscript drafts. Any use of trade, firm, or product names in this manuscript is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Conflict of interest
The authors declare that they have no conflict of interest.
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