White-nose syndrome has killed over 6 million North American bats since its discovery in 2006, causing mass suffering and population collapses in multiple cave-dwelling species.
White-nose syndrome causes acute and prolonged suffering in affected bats. The fungus grows on skin during hibernation, causing irritation that wakes bats from torpor. Awoken bats burn their fat reserves, leave hibernacula during winter, and die from hypothermia, starvation, or exhaustion outside. Mass deaths in hibernating colonies mean thousands of bats experience this suffering simultaneously. Biosecurity measures including decontamination of caving equipment have slowed spread. Research into probiotic treatments and fungicides shows promise. Probiotic Pseudomonas fluorescens applied to bat skin before hibernation has reduced mortality in some trials. The scale of population decline means ecosystem services including insect pest control are significantly impaired.