When bats come to mind, people generally think of horror movies and vampires, but bats actually play an important role in the ecosystem. But they’re in danger.

White Nose Syndrome, WNS, was discovered in New York in 2006 and has been affecting the US and Canadian bat populations ever since, The Spectrum newspaper reported. It’s a white fungus that attacks the skin of the bats while they hibernate and wakes them. The bats attempt to clean off the fungus, and it gets on their ears and noses — hence the name White Nose Syndrome.

Since WNS attacks bats during hibernation, the bats spend precious energy awake and using up their food stores, essentially starving them to death. There is no known cure, and it has a 90-100% fatality rate. WNS has made its way across the US and only a few states are currently WNS free: Utah, Nevada, Idaho, Colorado, Arizona, Florida, and Louisiana.

WNS spreads through pores that travel on human’s shoe wear and gear they might bring into caves. It also spreads through bat-to-bat contact, spreading rapidly since fungus thrives in cold, dark places like caves.

“WNS is not that big of a deal in places that have already been affected and it seems to hit certain species of bats harder than others,” said Kimberly Dickerson, WNS regional coordinator for Mountain-Prairie Regions.

Climate plays a large role in the spread of WNS and places like Florida have no reported cases because they don’t have caves where bats hibernate. Utah doesn’t have an especially large number of caves and in Southern Utah, it tends to stay warm year-round. Enough so that bats can be seen flying around for most of the year and have a shorter hibernation period.

“There are probably around a dozen bat species in Washington County,” Keith Day, a wildlife biologist, said.