White-nose syndrome (WNS), a deadly disease that has killed more than 5.7 million bats in eastern North America, has officially spread to the West. The United States Geological Survey and Fish and Wildlife Service recently confirmed the fungus caused the death of a little brown bat in Washington State.

WNS was first documented in North America in 2007 in New York. Since that time, WNS has been confirmed in 28 U.S. states and five Canadian provinces (New Brunswick, Nova Scotia, Québec, Ontario and Prince Edward Island). It has affected more than 50 per cent of the 47 bat species living the United States.

The fungus has the potential to wipe out 100 per cent of bats sharing a roost for hibernation. Biologists in Canada and the U.S. are trying to slow down the spread of the disease in North America. The Wildlife Conservation Society of Canada has recommended that Canadians:

• Reduce their use of pesticides to conserve habitats already in-use by bats (to prevent bats from wasting their precious fat stores scouting new locations)
• Decontaminate their outdoor gear by soaking it in 60 C water for twenty minutes if they have visited caves in Canada, the U.S., Asia or Europe

WNS is caused by the fungus Pseudogymnoascus destructans (formerly known as Geomyces destructans). The fungus flourishes in cold environments making chilly caves and other hibernation spots, like mines, prime breeding locations.

Apropos to its name, the fuzzy white fungus spreads over the hairless, exposed parts of a hibernating bat—namely its nose, wings and ears. It disrupts the sleeping patterns of hibernating bats, causing them to fly outside during the day. Bats with WNS burn double the energy of non-infected bats during hibernation, causing them to prematurely deplete their fat stores and starve.