White-nose syndrome has killed over 7 million bats in North America. The disease causes severe welfare harms and population collapse with cascading ecological consequences.
White-nose syndrome causes profound individual welfare harms through a mechanism that forces bats into physiologically catastrophic states during hibernation. Repeated premature arousal during winter causes bats to burn fat reserves desperately needed for survival, creating progressive starvation in animals that cannot find food in cold conditions. Affected bats suffer from progressive weakness, dehydration, and the stress of a dysfunctional immune response before dying. The scale of mortality represents billions of individual suffering events across the North American bat population. Welfare interventions including probiotic applications that suppress fungal growth on bat skin show promise and represent a rare opportunity to reduce disease-related welfare harms in wild animals at population scale.