White-nose syndrome

White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018.^[1] The condition is named for a distinctive fungal growth around the muzzles and on the wings of hibernating bats. It was first identified from a February 2006 photo taken in a cave located in Schoharie County, New York.^[2] The syndrome has rapidly spread since then. In early 2018, it was identified in 33 U.S. states and seven Canadian provinces; plus the fungus, albeit sans syndrome, had been found in three additional states.^[3] Most cases are in the eastern half of both countries, but in March 2016, it was confirmed in a little brown bat in Washington state.^[4] In 2019, evidence of the fungus was detected in California for the first time, although no affected bats were found.^[5]

The disease is caused by the fungus Pseudogymnoascus destructans, which colonizes the bat's skin. No obvious treatment or means of preventing transmission is known,^[6][7] and some species have declined by more than 90% within five years of the disease reaching a site.^[8]

The US Fish and Wildlife Service (USFWS) has called for a moratorium on caving activities in affected areas^[9] and strongly recommends to decontaminate clothing or equipment in such areas after each use. The National Speleological Society maintains an up-to-date page to keep cavers apprised of current events and advisories.^[10]