Rare syndrome infecting local bats

Apr. 30, 2013 @ 05:26 AM

What is White-nose Syndrome?

White-nose Syndrome (WNS) is a fungal disease that has killed more than five million bats across the northeast and mid-Atlantic United States during the past six years and continues unchecked. Bats with WNS may exhibit a white fungus that is found around the muzzle, ears, or wings of affected individuals. Other bat symptoms include moving to the entrance of the caves and often coming out of the caves and flying around in the middle of the day during winter months. Bats displaying this abnormal behavior have reduced fat reserves. Although it is normal for bats to occasionally interrupt their winter roosting, they are not equipped to withstand the drain on their fat reserves resulting from flying more often and during the day, a behavior thought to be caused by the irritation of the fungus. Many bats are non-responsive and many have been found dead both inside and outside caves.

Source: Bureau of Land Management

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A disease originating in Europe is taking a deadly toll on the bat population in western North Carolina.

Biologists with the North Carolina Wildlife Resources Commission and the U.S. Fish and Wildlife Service confirmed that White-nose Syndrome is the culprit which is responsible for killing an unknown number of cave-hibernating bats. The disease, however has no affect on humans.

Officials confirmed that one bat found in a cave on The Nature Conservancy's Bat Cave Preserve in Rutherford County tested positive for the disease.

"We can't say anything for sure about the bat population in Rutherford County," said Kendrick Weeks, mountain wildlife diversity supervisor for the NC Wildlife Resources Commission. "This is the first confirmation from the county and there could be more."

While the number of infected bats remains a mystery, wildlife officials have taken note of the fact that the number of hibernating bats in western North Carolina has declined sharply over the last two years.

Officials said some locations have seen up to a 95-percent decline in hibernating bats over that time.

"In general, across western North Carolina we have significant infection ... on the average of 70 to 80 percent," Weeks said.

Wildlife Commission biologists documented a significant decline of hibernating bats in a retired mine in Avery County. Two years ago, before the disease was discovered, there were over 1,000 bats in the mine. The number dropped to around 65 in 2013. The disease was first discovered in 2011 in Avery, Yancey, McDowell and Transylvania counties. Bats in Haywood County infected by the disease were discovered in 2012.

Buncombe and Rutherford counties are the latest sites to have bats test positive for the disease that can be fatal in "a large number" of the bat species that contract the disease. Wildlife officials are currently testing bats found with signs of the disease discovered in Swain County.

Weeks said that, while it is not certain, the origin of White-nose Syndrome can be traced back to Europe. He said exotic bats on that continent have been found to have the disease but have not died as a result. According to the U.S. Geological Survey, the disease has had an impact on bats from Nova Scotia to Tennessee, North Carolina and South Carolina.

He said that if the current bat population continues to drop, there could be additional effects.

"For those species that are more affected, those populations could continue to decline," Weeks said. "The ecological theory could show that because of the decline of those species, we could see an increase in other species that are not prone to the disease."

As for now, Weeks said the Wildlife Resources Commission is working to ascertain accurate population counts of bats in the area so they can determine the exact effect the disease has had on bats. He said there has been discussion on additional testing to help stop the spread.

"There is some debate about it and discussion about what can be done," Weeks said. "There is a man-made cave that was created in Tennessee that can be used to test different theories to prevent the spread of the disease."