Data from: Boreal toad survival varies by degree of attenuation and adaptation of a fungal pathogen

Batrachochytrium dendrobatidis (Bd) is a fungal pathogen responsible for
dramatic declines of amphibian populations around the world. Experimental
exposure studies have documented differences in host susceptibility to Bd,
but variation in study designs may limit our ability to compare inferences
across studies. Using laboratory-maintained pathogen cultures that may
lose virulence over time (i.e., pathogen attenuation) or exposing hosts to
foreign or local strains are choices that could affect hosts differently.
To test how these study design choices affect resulting inference, we
exposed a vulnerable anuran species, the boreal toad (Anaxyrus boreas
boreas), to three strains of Bd that varied in passage history and
geographic origin and measured differences on host survival. We also
examined strain-specific information reported in 58 publications of Bd
exposure experiments to investigate the potential for reproducibility
across studies. We found that boreal toads exposed to strains with many
passes had higher weekly survival probabilities than those exposed to the
strain with few passes, indicating likely pathogen attenuation in strains
with higher passage history. We also found evidence for local adaptation
of Bd to its host. Eighty-eight percent of the publications summarized did
not report the number of Bd passages. Our findings suggest that strains
with fewer passes in culture are better suited for exposure studies
seeking to understand differences in host susceptibility and that the
amount of passes can dramatically affect the inference gained across
studies.