MADISON, Wis. - A fast-moving disease that has roared across the United States is having a devastating effect on Wisconsin's bat population.

A winter study indicates that White-nose syndrome is now present in the bat populations in 24 of 28 Wisconsin counties, and sites in their second and third years of known infection are seeing population decreases of 30 to 100 percent. 

"The disease has progressed in Wisconsin as it did out east," says Owen Boyle, species management section chief for the Department of Natural Resources Natural Heritage Conservation program. "That doesn't make the numbers any easier to see. The effect of white-nose syndrome on our cave bats in Wisconsin, as nationally, is catastrophic."

The Wisconsin Department of Natural Resources (DNR) reports that bat populations are important to agriculture and ecosystems, as a single bat can consume thousands of insects each night. Researchers estimate that bats save Wisconsin farmers alone $600 million to $1.5 billion on pesticides every year, and are also important to tourism and people who own cabins in the state. Studies are underway at the University of Wisconsin-Madison and elsewhere to understand such impacts.

White-nose syndrome is caused by a fungus that gathers on the nose, ears and wings of bats as they hibernate, causing them to wake more often and burn critical stores of fat that allow them to survive winter. At one site in Grant County where the fungus was discovered DNR surveyors found just 16 bats, compared to 1,200 just three years ago. White-nose syndrome was first officially discovered in Wisconsin in 2014.