From Michigan Department of Natural Resources
-- A recent statewide survey of 60 bat wintering sites in Michigan found no sign of white nose syndrome.
WNS is an invasive fungus fatal to bats that infects the skin and causes the energy reserves to deplete before the hibernation period is over.
The survey, conducted by DNR staff with Dr. Allen Kurta and Steve Smith of Eastern Michigan University, involved extensive surveillance of caves and abandoned mines across the northern Lower Peninsula and Upper Peninsula. The survey locations represent the major bat colony hibernation sites in Michigan, with some colonies numbering over 50,000 bats.
“Our survey efforts focused on areas where WNS would most likely first appear,” said Bill Scullon, wildlife biologist. “Given the speed this devastating disease has spread across the country, we’re pleased to have found no visible signs of WNS in Michigan this season. Unfortunately, all indications are the disease will eventually arrive here.”
Michigan’s bat species are insectivores and are a highly-beneficial as a natural insect control mechanism. Bats help protect agricultural crops and forests from damage done by insects such as corn ear worms and gypsy moths, and reduce the threat of insect-borne diseases such as West Nile virus. The economic benefit of a healthy bat population in Michigan has been estimated at $508 million annually, and more than $23 billion nationwide.
Geomyces destructans, the invasive fungus that causes WNS, is believed to have originated in Europe but has spread to 19 states and four Canadian provinces since it was first discovered in eastern New York in 2006. WNS has been confirmed in Ontario, less than 90 miles from the Michigan border, as well as in Ohio and Indiana.
The US Fish & Wildlife Service estimates that since WNS was first detected in the United States, more than 5.5 million bats from six different species have died from the disease, with the mortality rate nearing 95 percent in some affected sites.
Nine species of bats can be found in Michigan. Those at greatest risk of contracting WNS are cave-dwelling bats, such as little brown bats, big brown bats, tri-colored bats, northern long-eared bats, and the federally-endangered Indiana bats.
The species gather in large concentrations in caves and abandoned mines to hibernate during the winter months. Cold temperatures which normally help the bats conserve body fat during hibernation, is when the fungus that causes WNS grows optimally.
The fungus persists in the environment without a host and can be carried from one location to another by humans, Scullon said. There are no known human health risks associated with Gd, and no other wildlife species is known to be impacted by the fungus.
The DNR is cooperating with researchers, universities, state, federal and tribal agencies, landowners, and citizens to delay the spread of WNS to Michigan.
For more information, contact Bill Scullon at (906) 353-6651 about the survey or Michigan’s bat population. Additional information is available online at www.michigan.gov/emergingdiseases.