By Lee Bergquist

Milwaukee Journal Sentinel

MILWAUKEE — Could ultraviolet light be the magic bullet that saves bats from a deadly fungus?

A researcher from a federal laboratory in Madison is experimenting with the use of UV light to control a fungal disease known as white-nose syndrome, which has killed millions of cave-dwelling bats in the United States, mostly east of the Great Plains.

Wisconsin is one of the states affected by the devastation, and a state Department of Natural Resources official said the trend of infections here is rising sharply.

Bats are important for ecological and economic reasons. Their voracious appetite reduces the use of pesticides. A single little brown bat can consume 600 mosquitoes in an hour. Some species are also important pollinators.

Daniel Lindner, a research plant pathologist with the U.S. Forest Service, is receiving $155,947 from the National Fish and Wildlife Foundation, to study whether UV light can effectively kill the fungus, Pseudogymnoascus destructans, which causes white-nose syndrome.

The foundation announced the award Oct. 24.

In the future, the research could lead to refinements in the technology, such as placing rings of invisible UV light where bats hibernate to zap the fungus.

There is currently no cure for white-nose syndrome. For bats, it is usually fatal, but it poses no threats to humans, pets, livestock or other wildlife. The fungus originated in Europe and likely spread to the U.S. and Canada through human migration and agriculture.

Since its discovery in New York state in 2006, the disease has killed more than 6 million bats in 31 states, including Wisconsin, and five Canadian provinces.

While the fungus has not been found in Oregon, officials confirmed case of white-nose syndrome in a bat found in North Bend, Washington, in March 2016, according to the U.S. Forest Service, which maps the spread. Central Oregon is home to 14 species of bats, most of which hibernate in caves. The Deschutes National Forest contains more than 400 caves, with hundreds more caves on adjacent private and Bureau of Land Management administered lands, according to the Forest Service.

Federal and state wildlife officials have surveyed caves for the fungus, set up an online site for reporting sick or dead bats and continue to remind the public about cave closures and etiquette.

White-nose syndrome was first detected in Wisconsin in Grant County in 2014. It has since been found in 23 more counties.

A 2011 study in Science magazine examined the economic impact of bat populations and concluded that in Wisconsin alone bats provided an annual economic benefit ranging between $658 million and $1.5 billion.

The work of Lindner and others builds on research that showed UV light could help identify signs of the disease on the bodies of live bats without euthanizing them.

Other work to fight white-nose syndrome has included the use of naturally occurring bacteria to attack the fungus.

Lindner, who has received previous funding for work on UV light and bats, is experimenting with short-wave UV light that he said “packs more punch” than the long-wave UV light used for detection work.

The idea is to use extremely small dosages of the light that will kill much of the powdery white fungus, so bats have a better chance of surviving the winter.

In hibernation, white-nose syndrome infects the face, wings and ears of the bat, which disrupts their hibernation. The tiny mammals dehydrate and starve.

In early December, crews will collect 45 little brown bats at a hibernacula in northwestern Wisconsin and send them to Pennsylvania.

At Bucknell University, the bats will live in a captive hibernation facility. Then begins the labor-intensive job of holding individual bats and applying quick bursts of UV light. Afterward, they will be monitored during hibernation.

The research hopes to prove that UV light delivered in correct doses will “increase bats’ survival and help them make it through the winter,” Lindner said.

If the bats survive, they will remain in a captive program at the school, he said.

The next phase of the project, not yet funded, would be to engineer a system that would deliver pulses of UV light activated by motion or acoustics during the fall in major hibernation spots before bats settle down for the winter.

Lindner said a few systems could play a big role in saving hibernating bats because a single hibernaculum can house tens of thousands of bats. According to the Wisconsin DNR, three of the largest hibernacula in the state hold about 95 percent of the hibernating bat populations in Wisconsin.

Wisconsin was selected to donate little brown bats because the state is on the leading edge of the disease; states in the East do not have sufficient bat populations to draw from, according to Lindner.