Sarah Davis loves bats. They’ve been the wintertime residents of Linville Caverns for as long as she can remember, a marker of the seasons she looks forward to each year. The cave, a commercial cavern near Marion, has been in Davis’ family since the 1940s — she and the bats go way back.
“There would be hundreds of them in the winter, and I absolutely loved them,” Davis recalls.
Experiments conducted by a multi-disciplinary team of researchers from the U.S., Canada and Germany strongly suggest that the fungus, Geomyces destructans, which causes White Nose Syndrome in bats, is a recent invasive from Europe. WNS was first discovered in the U.S. in 2006 near Albany, N.Y. Since then it has spread to 19 states (as far south as Alabama and as far west as Missouri) and four Canadian provinces. It has killed an estimated 5.7 million bats.
WNS was named because of a white fungus grows around the muzzle, ears and wing membranes. The fungus causes bats to wake up more often during hibernation, which in turn depletes their fat reserves and leads to starvation and death.
Researchers from the University of Winnipeg and the Western College of Veterinary Medicine (WCVM) reported their findings on April 9 in the online edition of the Proceedings of the National Academy of Sciences. Scientists were puzzled because bats from Europe had been discovered with WNS but it wasn’t lethal. To try and learn what was going on, disease-free bats were collected from caves across Manitoba and brought to WCVM for study. A third of the bats were inoculated with Geomyces destructans (Gd) from Europe; a third was inoculated with the fungus from North America and a control group was kept fungus-free.
Both inoculated groups of bats soon began showing the same telltale signs of WNS. The bats with WNS were emaciated and near death weeks before the 120-day experiment was scheduled to end and were euthanized. The control group was all healthy after the 120 days.
The research led scientists to believe that the European bats had evolved along with the Gd and developed some kind of immunity, while bats in North America had never been in contact with the fungus until that outbreak in 2006.
Researchers say the study provides a small glimmer of hope. If enough North American bats survive WNS, they will, hopefully, develop some immunity like their European cousins. But it appears to be a race against time as this deadly disease races across North America.
More studies are planned to try and discover how European bats combat the fungus, in hopes of finding a way to slow the spread of WNS in the U.S. and Canada. Some people think of bats as scary things. But a world without bats could, actually, be much scarier. One little brown bat weighing around one ounce can eat up to 1,200 insects per hour. And the little brown is but one of 45 species of bats found in the U.S. In one study, 150 big brown bats surveyed throughout one summer were reported to have eaten enough adult cucumber beetles to prevent the hatching of more than 30 million cucumber beetle larvae. Researchers in the U.S. have estimated that the current die-off of bats in North America will cost the agricultural industry $3.7 billion dollars annually.
Biologists recently confirmed white-nose syndrome at a third site in North Carolina, meaning two counties are now positive for the disease that has killed hundreds of thousands of bats in the eastern United States.
The disease was confirmed late last month in Yancey County. It was previously discovered in a retired Avery County mine and in a cave at Grandfather Mountain State Park.
“We knew that white-nose syndrome was coming and began preparing for its arrival, but we have a lot of work to do to address the impact of this disease on bats and our natural systems” said Chris McGrath, wildlife diversity program coordinator in the N.C. Wildlife Commission’s Wildlife Management Division.
While much remains to be learned about white-nose syndrome, there is evidence that people may inadvertently spread the fungus believed to cause the disease from cave-to-cave. Therefore, the most important step people can take to help bats is staying out of caves and mines.
While there are no known direct human health effects of the fungus that causes white-nose syndrome, the impact upon humans, other wildlife, and agriculture as a result of declines in bat populations could be substantial. Bats play a significant role as night-flying insect predators.
At this time, the fungus appears to grow on bat skin in the cave environment during hibernation. Infected bats may spread the fungal spores to other bats and roosts during the warmer summer months; however, the fungus only grows in a narrow range of temperatures (41 to 56 degrees Fahrenheit) in high humidity conditions.
White-nose syndrome, the disease that has killed hundreds of thousands of bats in the Eastern United States, has been discovered in a retired Avery County mine and in a cave at Grandfather Mountain State Park, marking the arrival of the disease in North Carolina, according to a media alert sent out today (Feb. 9) by the N.C. Wildlife Resources Commission.
On Feb. 1, a team of Commission biologists were conducting a bat inventory of the closed Avery County mine where they saw numerous bats displaying symptomatic white patches of fungus on their skin. Five bats from the mine were sent to the Southeastern Cooperative Wildlife Disease Study unit at the University of Georgia for testing, which confirmed the presence of white-nose syndrome.
In late January, a team of state, federal, and private biologists were conducting a bat inventory of a cave at Grandfather Mountain when they discovered a single dead bat. Following state white-nose syndrome surveillance protocols, the bat was sent for testing and it has been confirmed for white-nose syndrome.
“White-nose syndrome is confirmed in Virginia and Tennessee, so we expected we would be one of the next states to see the disease,” said Gabrielle Graeter, a biologist with the N.C. Wildlife Resources Commission. “This discovery marks the arrival of one of the most devastating threats to bat conservation in our time.”
In the Northeast, the disease has decimated some species of bats. It seems to be most fatal during the winter months, when hundreds of bats are hibernating together in caves and mines. It’s not known if the disease will similarly affect all species in all regions of the country, though bat mortality and the diversity of species affected in the Northeast suggest the impacts will be significant.
The discovery of white-nose syndrome comes as Commission biologists work through bat inventory and white-nose syndrome surveillance efforts at numerous caves and mines in Western North Carolina this winter as part of a grant awarded by the Service to several states on the leading edge of the disease’s spread.
North Carolina is home to three federally endangered bats, the Virginia big-eared, Indiana, and gray. Virginia big-eared bats are known from the.
“The discovery does not bode well for the future of many species of bats in western North Carolina,” said Sue Cameron with the U.S. Fish & Wildlife Service. “Although researchers are working hard to learn more about the disease, right now so little is known. There has been some evidence that humans may inadvertently spread the disease from cave to cave, so one simple step people can take to help bats is to stay out of caves and mines.”
“Cavers are passionate about what they do and we truly understand that asking them to stay out of caves is no small request and we greatly appreciate their sacrifice,” said Cameron, noting that the western North Carolina caving club, Flittermouse Grotto, has been very supportive of efforts to protect the area’s bats.
In 2009, fearing the disease could be transferred from cave to cave by humans, the Service released a cave advisory asking people to refrain from entering caves in states where white-nose syndrome has been confirmed and all adjoining states. The North Carolina Wildlife Resources Commission holds a protective easement on the mine and both it and the Grandfather Mountain cave have been gated and closed to the public for years to protect hibernating bats.
White Nose Syndrome just miles from WNC
The Tennessee Wildlife Resource Agency (TWRA) announced in mid-February that two bats from Worley’s cave had tested positive for White Nose Syndrome (WNS).
The cave, officially designated Morrell Cave by the U.S. Board on Geographical Names in 1980 but more commonly known as Worley’s or Morril’s cave, is located just southeast of Bluff City, Tenn., only about an hour and a half from Asheville.
Two tri-colored bats (formerly eastern pipistrelle) tested positive for the fungus (Geomyces destructans). While scientists are still not one hundred percent sure that the fungus is the sole causative agent, bat-to-bat-transmission of the fungus has been observed.
Whatever the cause, the malaise is clearly catastrophic. Mortality in some affected hibernacula has exceeded 90 percent. It is estimated that somewhere between one-half million and one million bats have succumbed to WNS, including at least 25,000 endangered Indiana bats.
Six species of bats — Indiana bat, little brown bat, big brown bat, northern long-eared bat, small-footed bat and tri-colored bat (formerly eastern pipistrelle) — are known to be susceptible to WNS.
Tennessee joins New York, New Jersey, Pennsylvania, New Hampshire, Connecticut, Vermont, Massachusetts, West Virginia and Virginia to become the tenth state to document WNS. Worley’s cave is the most southern and most western site, to date, where WNS has been recorded. The cave is only about 65 miles from known infected sites in Virginia.
But the prospect of further western and/or southern spread is a scary prospect for biologists and bat fanciers. Tennessee may have more caves than any state in the nation and a single cave in the Great Smoky Mountains National Park is a hibernaculum for nearly nine percent of the total estimated population of endangered Indiana bats.
And now for things that make you go hmmmmm....
You and I and all the taxpayers across this great land have paid about $14 million for ivory-billed woodpecker conservation since 2005. Never mind the fact that not one ivory-billed woodpecker has been conclusively documented since the late 1930s early 1940s.
Bat researchers are overjoyed that the Obama administration has secured $1.9 million in funding for the study of WNS. Maybe if we glued feathers to their wings and took fuzzy videos, we could get some dollars to study this devastating disease.
Wait a minute! That would be forethought — what am I thinking?