ST. PAUL, Minn. (AP) — Lab tests have confirmed the presence of white-nose syndrome in bats at a state park in northeastern Minnesota, marking the first time the state has seen a die-off due to the disease, the Department of Natural Resources announced Wednesday,.
Several hundred bats were found dead near the mine entrance at Lake Vermilion-Soudan Underground Mine State Park, mostly in late January during a cold snap, park manager Jim Essig said during a conference call with reporters. Lab tests confirmed the bats were infected with white-nose syndrome. They died of exposure after they suddenly hit the cold outside air when they should have been hibernating underground, he said.
An estimated 10,000 to 15,000 bats normally winter in the former iron mine and their prognosis is bleak.
“We can expect anywhere from 95 to 100 percent mortality,” DNR mammologist Gerda Nordquist said.
Park officials are still seeing a few bats come to the surface from the mine, but they’re not dying right immediately now that the weather is warmer, Essig said. He said they head toward wooded areas, where they likely die due to the lack of food and water.
The disease is named for the fuzzy white growth of fungus observed on infected bats. The disease has spread to 27 states and five provinces since it was first detected in eastern New York state in 2007, killing more than 5.7 million bats. But the harm extends beyond the bats themselves, because the animals are voracious predators on mosquitoes, as well as agricultural and forest pests.
The fungus was first detected in Minnesota in 2013 at both Soudan Underground Mine and Forestville/Mystery Cave state parks. Ed Quinn, a consultant with the state park system, said it’s not known yet whether bats that hibernate in southeastern Minnesota’s Mystery Cave have the disease.
It’s common for there to be some lag time from when the fungus is detected and the arrival of the disease, said Jeremy Coleman, national white-nose syndrome coordinator for the U.S. Fish and Wildlife Service.
Minnesota has seven bat species and the four that hibernate are all vulnerable, Nordquist said. White-nose syndrome is a particular threat in the cave country of southeastern Minnesota, she said. The disease is already devastating bats just across the Mississippi River in Wisconsin, she said. Bats just over Minnesota’s border with Ontario have also been hit hard.
The fungus usually spreads bat-to-bat and it’s not known to affect humans or other species. Public tours of the mine will continue because there’s a “very low risk” of people spreading it, Quinn said. But park officials will try to minimize that risk by continuing to have visitors walk over decontamination mats designed to remove fungus spores from footwear.
Scientists have been working hard for years to develop effective treatments but they’re still experimental, Coleman said.
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