In an effort to slow the spread of a bat-killing disease, the Missouri Department of Natural Resources decided on Wednesday to close 110 caves in 18 state parks and historic sites.

The move means bat caves are now off limits on most state and federal property in Missouri as a result of white nose syndrome, a fungus that has devastated bat populations in the northeastern United States.

The state's four tour caves at Onondaga, Meramec and Lake of the Ozarks state parks, however, will remain open for now.

The disease was detected in Missouri last month when a sharp-eyed field biologist noticed a small growth on the wing of a little brown bat in a cave in Pike County. Tests later confirmed the disease.

"We realize closing our bat caves will be an inconvenience for many cave explorers, but we feel this is the best interim measure to protect bats and our cave ecosystems from a serious threat," said Bill Bryan, director of the department's division of state parks.

Missouri is home to about 6,300 caves, many of which are popular recreation destinations that draw both experienced and amateur explorers.

In recent years, they've seen more and more bat caves closed to help the animals, hurt by habitat destruction and now disease.

"We knew it was only a matter of time before caves on private property were the only ones that would be left," said Alicia Lewis, vice president of the Mississippi Valley Ozark Region of the National Speleological Society. "But honestly we thought we might have a little more time here in Missouri."

The deadly disease was first discovered in New York in 2006 and has been rapidly spreading west. With the Pike County discovery, Missouri became the 12th state with a confirmed case of white nose syndrome, state conservation officials said.

Many mysteries continue to surround white nose syndrome, which causes bats to wake from hibernation and fly outside their cave during the winter. Doing so burns up crucial fat supplies and causes the bats to either starve or freeze to death.

The fungus, which usually shows up on the bat's nose, poses no risk to humans and appears to be spread from bat to bat.

Because bats seem to be the disease's primary vectors, many cave explorers have objected to closures being ordered across the country.

Members of the state's organized caving groups say they'll abide by the new closure rules, but aren't sure restrictions will do much good to stop the spread of white nose syndrome.

"Putting myself in the shoes of our wildlife managers and biologists, I realize they have to do something," said Jim Sherrell, president of the Middle Mississippi Valley Grotto. "But in the end, they're going to be pretty powerless to control bats. That's why they're putting this on the cavers."

Still, scientists suspect people may inadvertently spread the disease when they go into caves, perhaps through fungal spores on hair, clothes or equipment.

That's one of the reasons why the U.S. Forest Service voluntarily closed caves last year in 20 states, including Missouri and Illinois, where there have been no confirmed reports of the disease. In Missouri, access was restricted to 600 caves in the Mark Twain National Forest.

The state of Illinois closed the caves on the property it owns shortly after white nose syndrome was confirmed in Missouri last month.

Also on Wednesday, the U.S Fish and Wildlife Service announced it was awarding almost a half a million dollars in grant money to 23 states combatting white nose syndrome.

Missouri will receive more than $32,000 to erect cave gates and to help implement its white nose syndrome state response plan.