A disease responsible for the deaths of millions of bats has spread in Illinois.
The white-nose syndrome gets its name from a fungus that grows on affected bats' noses. Scientists say infected bats often show odd behavior - like taking daytime flights - when they're supposed to be hibernating. It's suspected that depletes their fat reserves, and causes the bats to become emaciated, and eventually die.
Illinois tried to ward it off; caves managed by the state have been closed to the public since 2010.
Still, the disease was first detected in Illinois bats in 2013, in Hardin, LaSalle, Monroe and Pope Counties.
New tests from the U.S. Geological Survey show it has spread. Bats from Union, Saline, Johnson and Jackson Counties in southern Illinois tested positive.
White-nose syndrome isn't harmful to people or pets, but it is very lethal to bats -- and that has harmful ecological repercussions; bats' appetite for insects means they're nature's built-in pest control. There's no known cause, or cure.
