Initial assessment of host susceptibility and pathogen virulence for conservation and management of Tasmanian amphibians

The disease chytridiomycosis, which is caused by lethal fungal pathogen Batrachochytrium dendrobatidis, is considered a threat to Tasmanian amphibians, but little is known about the susceptibility of Tasmania’s amphibian species or the likely impacts of infections. We identified threatened and endemic species with prioritization rules and the aid of predictive risk models. We also conducted controlled infection experiments in order to test the pathogenicity of, and host susceptibility to, a Tasmanian isolate of B. dendrobatidis. Of the species prioritized for disease testing, the endemic Tasmanian Tree Frog (Litoria burrowsae) sustained high infection intensities and high (100%) mortality rates. The Green and Golden Frog (Litoria raniformis) became infected, but only 22% of exposed frogs died. Our results verify the pathogenicity of a local B. dendrobatidis strain and identify a highly vulnerable amphibian species, the Tasmanian Tree Frog. Our results are a critical component of Tasmanian conservation management programs, which are now enacting disease mitigation efforts. Thus, we demonstrate the importance of incorporating information on host susceptibility and B. dendrobatidis pathogenicity into risk analyses for management of amphibians threatened by chytridiomycosis.