White-nose syndrome affects cave hibernating bats throughout eastern North America and adjacent Canada. This fatal disease continues to cause mass mortality and precipitous population declines. Current morbidity estimates approach 7 million, impacting > 200 hibernacula within 28 states and five Canadian provinces. Currently, white-nose syndrome affects at least seven species of hibernating insectivorous bats. Previously common species throughout the northeastern United States are presently at risk of regional extirpation or extinction due to white-nose syndrome. Pseudogymnoascus destructans, the causative agent of white-nose syndrome, thrives at temperatures of 3-15 ℃ and > 90% relative humidity, conditions equivalent to bat hibernacula and bodies of hibernating bats. P. destructans affects bats by increasing the frequency and duration of arousals from the torpor of hibernation.
Characteristics of white-nose syndrome include cutaneous lesions on the flight membranes; white fungus evident on the muzzles, wings, and ears; and aberrant behavior. Abnormal activity may include bats flying outside at temperatures at or below freezing; bats clustering near hibernacula entrances; and deceased or moribund bats on the ground or on buildings, trees, or other structures.