Chytridiomycosis in Arizona (USA) Tiger Salamanders
Elizabeth W. Davidson1, Allan P. Pessier2,3, Joyce E. Longcore4, Matthew Parris1, James Jancovich1, Jesse Brunner1, Danna Schock1, and James P. Collins1
1 Department of Biology, Arizona State University, Tempe, AZ 85287-1501 USA;
2, Zoological Society of San Diego, San Diego, CA 92112-0551;
3(Current Address) University of Illinois Zoological Pathology Program, Loyola University Medical Center, Maywood, IL 60153;
4 Department of Biological Sciences, University of Maine, Orono, ME 04469-5722
Email: e.davidson@ASU.edu
Twenty-seven out of 54 metamorphosed tiger salamanders, Ambystoma tigrinum stebbinsi, collected during routine field sampling in the San Rafael Valley in Southern Arizona, USA in November and December, 1999, had small black spots on their ventral abdomen and on the dorsal surfaces of the head. Five of these animals were returned to the laboratory for observation. Skin shed into laboratory holding containers contained profiles consistent with infection with the chytrid, Batrachochytrium dendrobatidis, and histologic examination confirmed the presence of intracellular chytrid thalli. Histologic lesions differed slightly from cases of anuran chytridiomycosis in that affected animals had only minimal to mild hyperkeratosis and mild inflammatory cell infiltrates.
We have cultured this fungus and examined its ultrastructural characteristics and its pathogenicity to native Arizona salamanders under laboratory conditions. Zoospores from pure cultures of Batrachochytrium isolated from A. tigrinum and from the lowland leopard frog, Rana yavapaiensis, from Southern Arizona were both infectious to A. tigrinum metamorphs, but did not lead to mortality during 60 days at 18C. Studies of the infectivity of the salamander chytrid to R. yavapaiensis are in progress. This represents the first well-documented case of chytrid infections in field-collected urodeles.