Bd isolation and quantification
All toads received 1.5 x 105 zoospores of their respective strain in a 5-8 mL inoculum pipetted onto their dorsal surface. The inoculum was composed of ASW that was rinsed from 1% tryptone agar plates that either were Bd+ (strain specific Bd exposure) or Bd-free (control, sham exposure). All toads were swabbed before, two weeks after, and 70 d after exposure or upon mortality. During each swabbing event, a sterile swab was passed over the ventral surface from snout to vent and each leg from hip to toe five times before being frozen at -80ยบ C. Bd DNA was extracted from the samples using Prepman Ultra, and intergenic transcribed spacer 1 (ITS1) region copy numbers were quantified using quantitative-PCR(Boyle et al.2004). To compare Bd loads across strains with differing ITS1 copy numbers, we transformed our qPCR results to zoospore equivalents (see Supplemental Methods and Results) (Longo et al. 2013).