California prepares for White-nose Syndrome in bats

White-nose Syndrome (WNS) is an emergent disease decimating bat populations in the eastern United States.  As of 2017, 31 U.S. States and 5 Canadian Provinces have confirmed cases of WNS. The fungus Pseudogymnoascus destructans (Pd) is responsible for the clinical signs of WNS, which include lesions on wing tissue and white fungal growths often visible on the nose, muzzle and wings.  As Pd colonizes a hibernating bat, the associated irritation causes the bat to wake up prematurely and expend vital energy resources in order to mount an immune response to the disease.  Unfortunately, this early arousal from hibernation forces bats to forage in winter conditions with extremely limited food availability and often results in dehydration and starvation.

White Nose Syndrome cases have not been detected to date in California, but the disease was detected in Washington State in 2016.  Bat biologists practice a strict WNS prevention protocol when handling bats in order to reduce the potential spread of the fungus.

A bat showing signs of WNS. From

The Wildlife Investigations Laboratory recently hosted a WNS/Pd Surveillance Best Practices Workshop led by Dr. Anne Ballmann of the USGS National Wildlife Health Center.  Participants included representatives from CDFW, USGS, USDA, CDPH, and USFWS.  The workshop presented the most current information on WNS disease ecology and provided practical, hands-on training in non-invasive surveillance techniques including environmental substrate sampling, UV light screening for fungal detection, and wing swabbing for laboratory analysis.  In the event a participant encounters a sick bat, training was also provided on proper euthanasia methods.  Most importantly, participants were trained in the most effective decontamination protocols in order to minimize the risk of anthropogenic spread of the fungus.  This training is part of a nationwide collaborative effort to study WNS and its causative agent, P. destructans, and help monitor and manage the disease to aid in the overall conservation of bat populations.

The Wildlife Investigations Lab is currently monitoring bat mortalities throughout the state in an effort to detect potential WNS occurrences.  Please report any sick or dead bats to  For more information on White-nose Syndrome and screening techniques, you can visit