Putative resistance and tolerance mechanisms have little impact on disease progression for an emerging salamander pathogen

1. Resistance and tolerance are unique host defense strategies that can limit the impacts of a pathogen on a host. However, for most wildlife-pathogen systems there are still fundamental uncertainties regarding 1) how changes in resistance and tolerance can affect disease outcomes and 2) the mechanisms underlying resistance and tolerance in host populations.

2. Here, we first compared observed patterns of resistance and tolerance and their effects on disease outcomes among salamander species that are susceptible to infection and mortality from the emerging fungal pathogen Batrachochytrium salamandrivorans (Bsal). We then tested whether two putative mechanisms that contribute to host resistance and tolerance, skin sloughing and skin lesion reduction, predicted reduced Bsal growth rate or increased host survival during infection, respectively.

3. We performed multi-dose Bsal challenge experiments on four species of Salamandridae found throughout North America. We combined the labora...