Wildlife researchers are alarmed by the first discovery of a bat with a deadly disease called white-nose syndrome west of the Rocky Mountains.

Hikers found the sick little brown bat about 48 kilometres west of Seattle, Wash., on March 11 and took it to a wildlife rescue organization for care, the U.S. Geological Survey reported in late March. It died two days later, and testing confirmed it had the fungus that causes white-nose syndrome.

The disease, which causes white patches to grow on bats' noses and wings, has killed more than six million bats in 28 U.S. states and five Canadian provinces of eastern North America since it was first discovered in eastern New York in the winter of 2006/2007.

"We are extremely concerned about the confirmation of WNS in Washington state, about 1,300 miles from the previous westernmost detection of the fungus that causes the disease," said Dan Ashe, director of the U.S. Fish and Wildlife Service, in a news release.

Craig Willis, a bat researcher at the University of Winnipeg, said the discovery is "an alarming development."

He told CBC's The Current that the disease has been moving westward about 300 kilometres a year. The Rocky Mountains were thought to be a significant barrier for bats.

"We thought we had at least a decade if not forever."

Scientists were already worried about a disease killing bats in the east, now it's on the move towards the west. The Current first told you about White Nose Syndrome in 2008 - so destructive it brought researchers to tears. Today we have an update. 7:26

He said it's possible that humans spread the fungus, which can survive on people's boots, climbing gear or caving gear.

But the discovery also highlights how the public can help scientists deal with the disease, by reporting sick bats.

He said the disease hasn't yet been found in Western Canada, and the Washington case is so far the only report in the western U.S.

He advised Canadians to be on the lookout and to contact the Canadian Wildlife Health Cooperative if they find a sick bat.

He said people who live in Manitoba or further east can also help monitor bats by participating in the citizen science project batwatch.ca.