White-Nose Syndrome and Cave Bats
White-Nose Syndrome (WNS) is a fungal infection that has killed millions of bats in North America since 2006. It is one of the most catastrophic wildlife diseases of modern times. Cave visitors are part of the transmission picture, and small behavioural changes can reduce the spread.
The fungus
Pseudogymnoascus destructans (Pd) is a cold-loving fungus that grows on the noses, ears and wings of hibernating bats. Infection disrupts hibernation cycles; bats wake too often, burn fat reserves, and die before spring. Mortality in some species exceeds 90%.
Origin and spread
Pd is native to Eurasia where Old World bats coexist with it without significant mortality. The fungus was introduced to New York state around 2006 and has spread westward across North America, reaching the Pacific coast by 2016. Human transport on caving equipment is one major spread vector.
Decontamination protocols
Cavers are now required to decontaminate gear between caves — strip clothing, wash boots and gear in detergent, sometimes quarantine kit by region. National parks have closed many caves to non-essential access; commercial show caves have added boot-wash stations.
Affected species
Little brown bat, Indiana bat, tricolored bat, big brown bat, northern long-eared bat. Indiana bat declines have led to endangered listings. Some western species are still in early stages of infection.
Recovery research
Probiotic treatments using bacteria from healthy bats show promise. Ultraviolet light treatment of hibernating bats has shown some protective effect. The fungus itself is unlikely to be eliminated; long-term recovery depends on surviving bat populations developing tolerance.
What visitors should do
Don't enter closed caves. Decontaminate gear between caves in different regions. Don't disturb hibernating bats. Respect cave closure dates (typically October-April for hibernation). Report bats acting unusually to wildlife authorities.
Explore on the map
See bat conservation caves on the interactive map.