A potentially lethal fungus has been rapidly spreading and has left over a million bats dead since its discovery in 2006 in upstate New York, but a recent statewide survey indicates that Michigan bats are safe — at least for now.
White nose syndrome (WNS) was not found in any of the 24 known bat wintering sites in a recent statewide survey conducted by the state Department of Natural Resources (DNR) in conjunction Dr. Allen Kurta and Steve Smith of Eastern Michigan University.
WNS is an emerging fungus-related disease of hibernating bats that has caused an unprecedented number of fatalities since it was first discovered 40 miles west of Albany, N.Y.
The disease has spread from New Hampshire to Tennessee and even west of Michigan.
“Basically, it has moved very quickly,” said Dan O’Brien, a DNR wildlife veterinarian. “Nothing has stopped it so far. It has gone around to the west to Missouri and Oklahoma. There is no particular reason or anything unique to Michigan that would spare us. There are already infected sites across Lake Huron and (Lake) Ontario.”
WNS is caused by Geomyces destructans, a cold-loving, white fungus that invades the skin of bats, particularly around their muzzles.
It’s still unknown exactly how the fungus causes death; however, scientists have postulated a possible explanation.
“We believe the fungus is inadvertently fatal,” O’Brien said. “What the science suggests is that it is very irritating to the bats and causes them to rouse from hibernation more than they would in the winter. Every time they wake up, they burn body fat, and they only store enough fat to get through the winter. When they are waking up more often than planned, they burn more body fat. They then need to feed, but there are no insects in the winter so they starve to death.”
Although bats tend to inspire a certain amount of fear thanks to tales of vampires, bats are actually quite useful, especially to the agricultural industry since they feed on a number of insects, including pests of crops and trees.
However, with the low reproduction rate of bats and the mortality rate of WNS-infected bats, there is concern about the detrimental effect this disease could have not only on Michigan bats but also on the state’s forests and crops.
There is currently no way to care for infected bats because there is no known cure, and rehabilitation is prohibited because of the risk of rabies to humans.
Most of the sites monitored for signs of WNS were across the northern Lower and Upper Peninsula where most of Michigan’s largest hibernacula are located in abandoned mines.
“Our targeted efforts focused on areas where WNS may show up first — our major winter hibernation colonies — while helping us to identify new populations and critical habitat,” said Bill Scullon, a DNR wildlife biologist, in a press release. “We’re very pleased to have found no signs of WNS this season. Unfortunately, it may only be a matter of time until we do find it.”
Although it seems likely that WNS would first strike the bat population in the Upper Peninsula, the fungus still poses a threat to bats in the Lower Peninsula because bats are able to transmit the disease to one another.
“It’s unusual to have an entire suite of species be at such grave risk from a single disease pathogen,” O’Brien said.
And bats are not the only vector for WNS. Studies show that people can transport the fungus spores through their clothes and equipment when they go exploring in infected caves.
As such, it’s important for the public to be aware of the disease so as not to inadvertently lead to a mass killing of Michigan’s bat population.
“We want to reach out to the public to make sure that people will not transmit the disease,” O’Brien said. “We not only want to educate the public on the disease, but on bats as a species. We want to try and counteract the negative opinions and myths people have about bats.”