Figure 3.

A conceptual model, developed here, for an ecological damage-response framework of B. dendrobatidis (Bd) pathogenicity. At either extreme of host response the host damage (disease) progresses toward mortality. At mid-levels of host response to Bd there may be no host damage (subclinical infection), depending on the environmental context. Environmental gradients may include elevation, temperature, temperature variability, pesticide concentration, intensity of co-infection, or other factors. Shown here is a reduced damage-response curve at low environmental humidity. Theoretically, chytridiomycosis is suppressed where environmental conditions are not conducive to Bd, but under some environmental conditions host defenses become critical for control of chytridiomycosis. Other damage-response curve shapes are possible for this opportunistic pathogen.