White-Nose Syndrome in North American Bats: What USGS Research Found

By Emily W. Lankau and Gail Moede Rogall, USGS National Wildlife Health Center. USGS Fact Sheet 2016–3084, December 2016.

White-nose syndrome (WNS) has killed millions of hibernating bats since it first appeared in New York in 2007. By December 2016 it had spread from the Northeast into the central United States and across eastern Canada, and had been confirmed in Washington, the only western State affected at that point. It is named for the fungus Pseudogymnoascus destructans, which often shows white on the nose, ears and wings of hibernating bats. The spread map shows where it has been found.

Wings of a little brown bat infected with WNS; the pale areas are typical of the fungus. Photo: C. Meteyer, USGS.

What the USGS found

The USGS has been central to the interagency response since 2008. Its studies:

• discovered the disease (Blehert and others, 2009);
• first described and named the cold-loving fungus (Gargas and others, 2009);
• set standard criteria for diagnosing it (Meteyer and others, 2009);
• proved that P. destructans causes WNS (Lorch and others, 2011);
• showed where the fungus lives and how it persists in caves (Lorch and others, 2012).

Better field screening under ultraviolet light (Turner and others, 2014), where infected wing areas glow yellow-orange, and new lab tests (Muller and others, 2012) have widened surveillance. The National Wildlife Health Center now helps State and Federal partners watch for the fungus in the Southeast, Midwest and West. Finding it early gives managers time to prepare.

How it kills

• Diagnosis: scientists look for a telltale microscopic pattern of skin erosion. White fuzz on the muzzle or wings is a field sign, but only lab testing confirms the disease.
• Behavior: infected bats wake from hibernation more often, cluster near cave entrances, and even fly by day in freezing weather.
• Body: infection sets off a cascade of physiological disturbances that can end in death from dehydration or starvation — with harm starting before any visible signs.

The toll

Deaths on this scale are unprecedented in hibernating bats. Little brown bats (Myotis lucifugus) have been hit hardest and could vanish locally or regionally. Small groups have been found surviving and breeding where numbers crashed, but they need protection from other threats. Recovery will be slow: females of most species raise only one pup a year. Long-term monitoring will show whether bats can rebound.

Species affected, as of December 2016:

Big brown bat. Photo: Ann Froschauer, U.S. Fish and Wildlife Service.

Northern long-eared bat. Photo: Pete Patavino, U.S. Fish and Wildlife Service.

The response

The U.S. Fish and Wildlife Service coordinates Federal, State and Tribal agencies and private partners under a National Plan (see whitenosesyndrome.org). USGS researchers work with them to track the fungus, limit its spread, reduce losses and help populations recover — including trials of microbes or chemicals that stop the fungus growing in caves, and possible vaccines.

USGS work on WNS includes:

• diagnosing bats sent in by Federal, State and Tribal agencies;
• studying how cave conditions affect the fungus's survival;
• studying transmission, spread and prevention;
• building better detection and surveillance tools;
• studying the microbes of caves and bat skin;
• watching hibernating bats for behavior changes;
• working out the physiology of illness and death;
• researching ways to prevent WNS and help bats recover;
• informing the public, policymakers, managers and scientists, and publishing the science.

Why bats matter

Bats eat insects that damage crops and spread disease, and many species pollinate plants and spread seeds. Research will show what losing them means for ecosystems.

More: USGS National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711; (608) 270-2400; nwhc.usgs.gov.

Sources

Based on White-Nose Syndrome in North American Bats—U.S. Geological Survey Updates, by Emily W. Lankau and Gail Moede Rogall, USGS Fact Sheet 2016–3084, U.S. Geological Survey; a work of the United States government in the public domain. The species list and the three photographs are taken from the fact sheet's PDF. Photographs credited to the New York Department of Environmental Conservation, the Wisconsin Department of Natural Resources, Virginia Tech, Virginia State Parks and an individual, and an ultraviolet figure adapted from a journal article, are not reproduced.