Investigations continue into the cause of a mysterious illness that has resulted in the deaths of thousands of bats since March 2008. At more than 25 caves and mines in the northeastern U.S, bats exhibiting a condition now referred to as “white-nosed syndrome” have been dying.

The U.S. Geological Survey (USGS) recently issued a Wildlife Health Bulletin, advising wildlife and conservation officials throughout the U.S. to be on the lookout for the condition known as “white-nose syndrome” and to report suspected cases of the disease.

USGS wildlife disease specialist Dr. Kimberli Miller advises that "anyone finding sick or dead bats should avoid handling them and should contact their state wildlife conservation agency or the nearest U.S. Fish & Wildlife Service field office to report their observation.”

The USGS National Wildlife Health Center in Madison, Wis. has received nearly 100 bat carcasses mostly from New York, Vermont, Massachusetts, and Connecticut. The syndrome affects species including the little brown, big brown, northern long-eared and eastern pipistrelle bats.

The condition was first observed in February 2007 in caves near Albany, N.Y. by the New York State Department of Environmental Conservation. Dead and hibernating bats had a white substance on their heads and wings. In early 2008, “white-nosed” bats were once again seen at hibernation sites.

Scientists have collected environmental samples from affected caves and mines in Vermont, New York and Massachusetts in an effort to determine the cause of the deaths. Live, dead and dying bats were documented in and outside of hibernation sites.

The most common findings in the bats have been emaciation and poor body condition. Many of the bats examined had little or no body fat; some exhibited changes in the lung that have been difficult to characterize; and a majority had microscopic fungi on their bodies.

The white substance observed on some bats may represent an overgrowth of normal fungal colonizers of bat skin during hibernation and could be an indicator of overall poor health, rather than a primary pathogen. Scientists from a variety of agencies are investigating underlying environmental factors, potential secondary microbial pathogens and toxicants as possible causes.

Web sites for additional information:

USGS National Wildlife Health Center On White Nose Syndrome

U.S. Fish and Wildlife Service

Bat Conservation International