All anuran specimens in the Wildlife Conservation Society's collections testing positive for Batrachochytrium dendrobatidis (Bd) were treated with
itraconazole and then studied
after treatment to assess the long-term effects of
itraconazole and the
drug's effectiveness in eliminating Bd carriers. Twenty-four individuals and eight colonies of 11 different species (75 total specimens) tested positive for Bd via polymerase chain reaction (PCR) on multicollection survey. All positive individuals and colonies were treated with a 0.01%
itraconazole bath
solution and retested for Bd via one of two PCR methodologies within 14 days of treatment completion, and all were negative for Bd. A total of 64 animals received secondary follow-up PCR testing at the time of death, 6-8 mo, or 12-15 mo post-treatment. Fourteen animals (14/64, 21.9%) were PCR positive for Bd on second follow-up. The highest percentage positive at second recheck were green-and-black poison dart frogs (Dendrobates auratus; 5/5 specimens, 100%), followed by red-eyed tree frogs (Agalychnis callidryas; 4/11, 36.4%), grey tree frogs (Hyla versicolor; 1/3, 33.3%), and green tree frogs (Hyla cinera; 3/11, 27.3%). Re-testing by PCR performed on 26/28 individuals that died during the study indicated 11/26 (42.3%) were positive (all via
DNA extracted from
formalin-fixed
paraffin-embedded skin sections). However, there was no histologic evidence of chytridiomycosis in any of 27/28 individuals. The small number of deceased animals and effects of postmortem
autolysis limited the ability to determine statistical trends in the pathology data, but none of the necropsied specimens showed evidence of
itraconazole toxicity. Problems with
itraconazole may be species dependent, and this report expands the list of species that can tolerate treatment. Although
itraconazole is effective for clearance of most individuals infected with Bd, results of the study suggest that repeat
itraconazole treatment and follow-up diagnostics may be required to ensure that
subclinical infections are eliminated in amphibian collections.