Chytridiomycosis, the disease caused by the fungal pathogen/ Batrachochytrium dendrobatidis/, has been linked to amphibian declines world wide. In the Sierra Nevada of California, /B. dendrobatidis /appears to be an important factor in the decline of the mountain yellow-legged frog, /Rana muscosa./ In some areas, invasion of the disease leads to rapid local population extinction. In other areas, however, /R. muscosa /populations appear to persist despite high prevalence of the disease. / /Dispersal in /B. dendrobatidis /occurs through motile zoospores, and/ /models indicate that external zoospore density may play an important role in the onset of chytridiomycosis. In order to determine the effect of water flow on zoospore density and the subsequent outcome of infection with /B. dendrobatidis, / 24 post-metamorphic /R. muscosa /were inoculated with /B. dendrobatidis/ and divided into two experimental groups, one flow and one control.
Animals in the no-flow group died significantly faster than those in the flow treatment (p<0.0001). Although mortality was high in both groups, the results suggest that water flow may significantly delay the onset of chytridiomycosis.
