Experimental Infection and Repeat Survey Data Indicate the Amphibian Chytrid Batrachochytrium dendrobatidis May Not Occur on Freshwater Crustaceans in Northern Queensland, Australia

Abstract

Chytridiomycosis is a fatal disease of amphibians, caused by the amphibian chytrid Batrachochytrium dendrobatidis. The disease is unusual in that it may drive many amphibian species to local extinction during outbreaks. These dramatic declines in host population numbers could be facilitated if the pathogen can grow as a saprobe or on alternative hosts, a feature common to other chytrid species. This is also supported by in vitro work that demonstrates B. dendrobatidis can grow and reproduce in the absence of amphibian cells. In a previous study, B. dendrobatidis was detected on freshwater shrimp from rain forest streams in northern Queensland, Australia, using diagnostic PCR. We set out to confirm and further investigate the presence of B. dendrobatidis on crustaceans by carrying out more extensive sampling of shrimp in the field, experimental B. dendrobatidis infection trials using shrimp and crayfish, and PCR verification of the presence of B. dendrobatidis from shrimp samples that previously tested positive. We could not confirm the presence of B. dendrobatidis on shrimp, and report that original positive tests in shrimp reported by Rowley et al. (2006) were likely false. Thus, we suggest that shrimp may not be an important reservoir host for B. dendrobatidis.