White-nose syndrome has killed over 90% of some North American bat populations and represents one of the most severe wildlife disease welfare emergencies in recent history.
White-nose syndrome causes prolonged suffering before death, with affected bats experiencing repeated metabolic arousal, dehydration, and starvation over weeks. The scale of mortality represents an enormous aggregate welfare harm and has severe ecosystem consequences given bats' role as insect predators. Probiotic treatments applied to hibernacula show that some infected colonies can be protected, but scaling treatment across the millions of roost sites where the disease has spread is logistically challenging. Disease spread prevention through cave closure and decontamination of caving equipment remains the most practical current tool.