DAO 92:165-174 (2010)  -  DOI: https://doi.org/10.3354/dao02238

Contribution to the DAO Special 'Chytridiomycosis: An emerging disease'

Treatment of chytridiomycosis requires urgent clinical trials

Lee Berger1,*, Rick Speare1, Allan Pessier2, Jamie Voyles1, Lee F. Skerratt1

1Amphibian Disease Ecology Group, School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Queensland 4811, Australia
2Amphibian Disease Laboratory, Wildlife Disease Laboratories, San Diego Zoo’s Institute for Conservation Research, San Diego, California 92112-0551, USA

ABSTRACT: Effective and safe treatments of amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), are needed to prevent mortality in captive programs, reduce the risk of disease spread, and better manage the disease in threatened wild populations. Bd is susceptible to a range of antifungal agents and low levels of heat (>30°C) when tested in vitro, but there are few proven methods for clearing adult amphibians of Bd, and acute drug toxicity is a problem for tadpoles and juveniles. In postmetamorphic animals, heat (32 and 37°C) is the only well-supported treatment. Antifungal drugs have not undergone rigorous testing—for example, trials were small or lacked controls and thorough post-treatment testing. In addition, pharmacokinetic studies have not been performed so there are no data on blood or tissue levels of antifungal agents. However, itraconazole baths have been widely used in amphibian rescue and conservation programs and anecdotal evidence suggests that they are effective for adults and subadults. In an experimental trial with tadpoles, a low dose of itraconazole cleared Bd but may have been associated with cutaneous depigmentation. Fluconazole appeared safe for tadpoles as it did not cause mortality, and future attempts to find an effective dose may be worthwhile. Palliative restoration of blood sodium and potassium levels by administration of electrolyte solutions appears useful in frogs with clinical chytridiomycosis. Randomised and blinded clinical trials, which include basic pharmacological studies, are urgently needed to provide comparable evidence for the safety and efficacy of treatment options which are likely to vary with amphibian species. Priorities are to validate and optimize the use of heat and itraconazole regimes.


KEY WORDS: Batrachochytrium dendrobatidis · Antifungal testing · Treatment · Chytridiomycosis · Heat · Clinical trial


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Cite this article as: Berger L, Speare R, Pessier A, Voyles J, Skerratt LF (2010) Treatment of chytridiomycosis requires urgent clinical trials. Dis Aquat Org 92:165-174. https://doi.org/10.3354/dao02238

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