Deadly bat disease in Dickinson

IRON MOUNTAIN – Department of Natural Resources officials in Michigan and Wisconsin have announced that the fungus known to cause significant rates of illness and death in North American bats has been detected for the first time within the two states’ borders.

In Michigan, white-nose syndrome has been found in Dickinson, Mackinac and Alpena counties. It was also discovered in Grant County in southwestern Wisconsin.

“These are the first confirmed white-nose syndrome cases in Michigan. Even though we’ve known this disease was coming, it is a disappointing day,” said Dr. Dan O’Brien, DNR wildlife veterinarian. “We will now shift gears and try to stop the spread of this serious disease.”

Dr. O’Brien declined to identify the exact location where the disease was found in Dickinson County. Officials wanted to keep local residents from disturbing the area, he said.

“The discovery is not a surprise but it’s a sad day for Wisconsin. We face the loss of multiple bat species and the benefits they provide to our ecosystems and our people,” added Erin Crain, who leads the Wisconsin Department of Natural Resources Natural Heritage Conservation Program.

“We knew this day would come because white-nose syndrome spreads rapidly bat to bat and bat to cave,” Crain said. “With great cooperation from mine and cave owners, we took aggressive steps to prevent human spread of the disease to Wisconsin, and we think those steps helped delay its arrival by several years, allowing more time for research and to learn from other states’ experiences. But we knew there would be no dodging the bullet. We now face the sad potential of bat die offs that will be felt at home and across the country.”

Wisconsin is home to several of the upper Midwest’s largest bat hibernation sites and historical estimates have put the population at 350,000 to 500,000 bats.

“It’s sad,” Dr. O’Brien said. He said Dickinson County area residents would probably not notice many bat die-offs until next winter. At that time, public campaign efforts would to be conducted to keep people away from them to prevent the spread of other diseases to humans.

While it’s well-know that bats eat mosquitoes, their diet mostly consists of moths and beetles, pests of agriculture and forest products industries, Dr. O’Brien said.

Five little brown bats from Michigan showing disease characteristics were collected in February and March during routine WNS surveillance by Dr. Allen Kurta and Steve Smith, researchers from Eastern Michigan University.

White-nose syndrome was diagnosed by Michigan State University’s Diagnostic Center for Population and Animal Health (DCPAH), in cooperation with the DNR Wildlife Disease Laboratory.

“At DCPAH we have to have our eye on emerging diseases and prepare our test capabilities early on so that we are ready when the need for testing arises,” said Dr. Tom Mullaney, DCPAH’s interim director. “We identified the fungus by PCR and through histopathology due to the specific presentation of the lesions. While we regret that this disease has arrived in Michigan, we will work closely with our DNR partners as they continue the next phase of their work.”

The diagnosis was then confirmed by the U.S. Geological Survey’s National Wildlife Health Center in Madison, Wis. The bats tested positive for Pseudogymnoascus destructans, the fungus known to be the causative agent of skin lesions observed in white-nose syndrome-affected bats.

The disease was first documented in 2006 in a cave in upstate New York. Eleven species of bat have been infected and over 6 million have died.

The disease has been confirmed in 25 states and the fungus has been found in three others, according to the U.S. Fish and Wildlife Service.

In 2010, the DNR, along with the agency’s federal and non-governmental partners, developed Michigan’s WNS Response Plan. The plan outlined two main pillars: 1) prevent the arrival and spread of white-nose syndrome as long as possible by mitigating the human-assisted movement of the fungus that causes the disease; and 2) conserve whatever bat populations remain after the disease has arrived by preserving abandoned underground mines and caves.

In northeastern states, where the bat disease has been present the longest, summer bat populations are down by 70-80 percent, and winter die-offs in some specific caves have been greater than 90 percent.

While there is no connection between white-nose syndrome and rabies, the DNR and Michigan Department of Community Health caution the public to avoid handling bats because of the risk for exposure to rabies. Bats in Michigan can carry rabies, a virus that infects the central nervous system of mammals, including people, and causes death in almost all cases. Rabies is most commonly spread by the bite of an infected animal. There are no known harmful effects to humans from white-nose syndrome.

“At this point, there is no effective treatment for white-nose syndrome and no practical way to deliver the treatment to millions of affected bats even if treatment existed. Rehabilitation of bats is prohibited in Michigan because of the potential for the exposure of humans to rabies,” said O’Brien. “The best thing the public can do when they find a dying or dead bat is to leave it alone and keep children, livestock and pets away from it.”

Bat die-offs can be reported through an observation report on the DNR website at or by calling the DNR at 517-336-3050.

The U.S. Fish and Wildlife Service requests that cavers refrain from caving in all white-nose syndrome-affected states and adjoining states. Cavers also should refrain from caving anywhere during the hibernation period (September May) to minimize disturbance and mortality to bats.

The loss of bats due to white-nose syndrome could be economically significant for agriculture and commercial forestry. A reduction in the bat population could lead to an increase in pests that are harmful to crops and trees.

Learn more about white-nose syndrome at the DNR website