There’s still no evidence of a deadly bat disease in Wisconsin. The Department of Natural Resources reports that a recent survey of 73 hibernating locations found no evidence of white-nose syndrome. The fungal disease has killed close to six-million bats in the eastern U.S. since 2006.

Wisconsin wildlife and agriculture officials are particularly concerned, because bats protect farm crops by killing insects. The disease causes bats to wake up during their hibernation. It rapidly depletes their energy supplies. Wisconsin has performed three studies, and nothing has turned up so far. Illinois confirmed white-nose syndrome in four counties so far this year. It was detected in 2012 in a cave in Iowa about 30 miles from the Wisconsin border.

The DNR has said it’s a matter of time before white-nose syndrome reaches Wisconsin, and the agency has procedures in place aimed at delaying that arrival. Visitors to caves are often asked to wipe off their shoes before entering and leaving, to prevent any disease from spreading. A recent UW Madison study found that infected caves where bats hibernate continue to have white-nose syndrome for at least two years after all surviving bats have left. That means that bats might not be able to rebuild their populations in a cave where the disease hits.