Towards a Better Understanding of the Use of Probiotics for Preventing Chytridiomycosis in Panamanian Golden Frogs
Populations of native Panamanian golden frogs (Atelopus zeteki) have collapsed due to a recent chytridiomycosis epidemic. Reintroduction efforts from captive assurance colonies are unlikely to be successful without the development of methods to control chytridiomycosis in the wild. In an effort to develop a protective treatment regimen, we treated golden frogs with Janthinobacterium lividum, a skin bacterium that has been used to experimentally prevent chytridiomycosis in North American amphibians. Although J. lividum appeared to colonize A. zeteki skin temporarily, it did not prevent or delay mortality in A. zeteki exposed to Batrachochytrium dendrobatidis, the causative agent of chytridiomycosis. After introduction of J. lividum, average bacterial cell counts reached a peak of 1.7 × 106 cells per frog ~2 weeks after treatment but declined steadily after that. When J. lividum numbers declined to ~2.8 × 105 cells per frog, B. dendrobatidis infection intensity increased to greater than 13,000 zoospore equivalents per frog. At this point, frogs began to die of chytridiomycosis. Future research will concentrate on isolating and testing antifungal bacterial species from Panama that may be more compatible with Atelopus skin.
KeywordsBatrachochytrium dendrobatidis Chytridiomycosis Atelopus zeteki Janthinobacterium lividum probiotic
We would like to thank the Houston Zoo and the Maryland Zoo in Baltimore that own all individuals in the Golden Frog Species Survival Plan for providing the animals. The Fish and Wildlife Service provided permits to conduct the experiment and IACUC approval was obtained from the Smithsonian National Zoological Park and the Maryland Zoo in Baltimore. We are thankful for the technical assistance provided by J. Becker, C. Crowe, M. Evans, D. Flaherty, W. Lynch, G. Reynolds, E. Smith, L. Ware, P. Wiggins, and V. Wine. We are grateful for advice from K. Murphy, V. Poole, K. Zippel, L. Padilla, and T. Walsh in setting up the experiment. This research was supported by the Anela Kolohe Foundation (B.G.), the Shared Earth Foundation (B.G.), the U.S. Fish and Wildlife Service as part of the Panama Amphibian Rescue and Conservation Project (B.G.), the National Science Foundation grants numbers 0640373 (R.N.H.), IOS-0619536 (L.R-S.), and IOS-0843207 (L.R-S.), and the Thomas F. Jeffress and Kate M. Jeffress Memorial Trust (K.P.C.M.).
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