Fig. 3

Molecular mechanistic model of white-nose syndrome (WNS) tolerance in bats. During hibernation, a bat’s body temperature, metabolic rate and immune system are lowered for up to six months, only increasing for periods lasting up to several hours during periodic arousal from torpor. Bat hibernation provides suitable conditions for Pseudogymnoascus destructans infection and development of the fungal disease WNS. The fungus initially grows on the skin’s surface and progresses toward invasive infection, whereupon it deposits large amounts of vitamin B₂ into skin lesions, leading to skin necrosis. In the most severe cases, either large areas of skin become necrotic or the immune system’s response to massive infection overwhelms the animal upon arousal. Molecular mechanisms supporting WNS tolerance are likely to include strengthening of skin integrity maintenance and enhancement of wound healing. Surprisingly, there may also be negative modulation of the immune response, which could otherwise deplete the bat’s energy reserves or cause death through immune reconstitution inflammatory syndrome [20]