WHITE FUNGUS is visible around the nose of this little brown bat hibernating in a West Virginia cave.
Image: JOHN M. BURNLEY/Photo Researchers, inc.
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On a summer evening three years ago my wife and I counted 75 little brown bats scrabbling out from behind four small shutters on our house in upstate New York and setting off for a night of insect foraging. A year later the number had swelled to 150; the moth and mosquito populations were becoming less bothersome than ever before. Then things took an abrupt turn for the worse: last year the numbers plummeted, and on a recent summer evening this year only six bats emerged.
The drop would come as no surprise to wildlife biologists in the Northeast. The house is just an hour's drive from ground zero of the worst disease outbreak in bat populations on record. First observed in Howe Caverns near Albany, N.Y., in early 2006, white nose syndrome has spread north to New Hampshire and Vermont and south to Virginia. At least a million bats in six species have already perished, and death rates at infected hibernacula range between 90 and 100 percent.
Many observers expect a wave of new outbreaks this year, even among previously uninfected bat species (so far the disease seems harmless to humans and other animals). Yet despite widespread concern and media attention, scientists are still trying to figure out exactly what is killing the creatures and are frantically searching for ways to stop it. And because bats are essential to the control of nocturnal flying insects, the outbreak could upset local ecologies, weaken the health of forests and even affect crop yields.
White nose syndrome (WNS) takes its name from a fungus that looks like a white, powdery substance on the muzzles, wings and ears of bats. The fungus, previously unknown to science, has been classified and named as Geomyces destructans. No one has proved it is the killer—it could be just an opportunistic invader taking advantage of some other infection—but many biologists think it is. It grows only between about 36 and 72 degrees Fahrenheit, a relatively cold range for a fungus but typical of the year-round temperatures in the depths of most U.S. caves. So far the only bats infected with the fungus rely on insects for food and on hibernation to survive the insect-free winter months.
According to Marvin Moriarty of the U.S. Fish and Wildlife Service, another piece of evidence that points to the fungus is that when it grows on the wings of the animals, it causes swelling and scarring. The wing membranes are essential for regulating physiological functions such as body temperature and blood pressure. Hibernating bats are already dangerously close to depleting their stored fat reserves before they emerge from torpor. If WNS interferes with their physiology, it could interrupt hibernation and lead the bats to use up more energy than they can afford. In short, they would starve. Supporting this theory is that many WNS victims are also emaciated, and bats from infected caves are unusually active in winter, perhaps in a futile attempt to find food.
To devise a plan to stop WNS, biologists want to know much more about the Geomyces fungus—its origins, distribution, mode of transmission and the like—as well as the bats’ reaction to it. Such data might, for instance, lead to a vaccine against WNS.
Funds for fighting WNS have been meager, however. A total of only $1.1 million, from government and private funds, has gone to scientific and control efforts since the disease appeared. Yet in testimony before a House subcommittee on June 4, biologist Thomas H. Kurz of Boston University stated that the funding needed to mount a realistic response is at least $17 million. This past May, 25 U.S. Senators and Representatives signed a letter to Interior Secretary Ken Salazar urging emergency funding for agencies with the expertise to “determine a cause and develop solutions to this crisis.”
Meanwhile the most visible response to WNS has been to declare caves and mines off-limits to visitors. But whether people are spreading the fungus around is unclear. According to Robert Zimmerman, a caver who has written extensively about the outbreak, the first places WNS appeared in Pennsylvania and West Virginia were “popular recreational caves.” Yet WNS has not been detected in other popular caving regions, notably those in Indiana, Tennessee, Alabama and Georgia. David Blehert of the National Wildlife Health Center in Madison, Wis., and his colleagues are working to culture the fungus from the floors and walls of caves, to determine whether clothing and equipment could spread the fungus.
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8 Comments
Add CommentVery interesting article. While it is very unfortunate this event is occurring could it be just nature taking its natural course of ebb and flow or could this be the direct result of mankinds attempt to eliminate germs all the while backfiring. There is already great concern regarding the impact of mass commercial introduction of anti-bacterial products into main consumption and their impact on the environment. While further study is needed to determine the exact cause here is something to chew on&could this be the result of the anti-bacterial solutions getting into the ground water where insects are born. The insects would be immune but carriers of a stronger stain of fungi. The bat would be exposed when devouring its nightly meal. Or could it be due to anti-bacterial tainted water seeping down into the caves where insects and bats live where it originally killed off the majority of the fungi only to create a stronger strain? Good luck Marvin.
Reply | Report Abuse | Link to thisD. Forsell
interesting theory D. ...a good example of this is my habit of gargling with hydrogen pyroxide; this friend who is a dental assistant in Stockholm was visiting and told me they were taught in school that there is a risk to this as it kills off ALL the bacteria in the mouth and leaves it open to fungal attack, which would represent in the form of white blotches, which i have noticed at times throughout the years....
Reply | Report Abuse | Link to thisso now i'll just spot-treat parts of my gums that need some attention...or just gargle part of my mouth lol
it's interesting, one is hard-pressed to find ANY HO2 at all in Sweden...but i'm glad i can get it here
i wonder if some people have over-used it to the extent they get constant fungal attacks that could cause asthma etc...hmmmm
rockjohny: I think you are referring to H2O2, hydrogen peroxide. I also think that it's bad practice to use too 'heavy' disinfectants, because that drives pathogens towards nastier types.
Reply | Report Abuse | Link to thisThe information currently available on WNS seems to imply that it is an invasive fungus. Geomyces are rarely pathogens, but this one seems very similar to one in Europe. European bats seem to get the disease but appear to be resistant to it. Like the chytrid fungus that is wiping out amphibians in Central America and Australia, I think it is a good guess that this pathogen developed on another continent and humans have inadvertantly imported it. The people working on the issue suspect cavers as being the vector (dirty shoes), but given a point of origin in Euoropean caves, perhaps we should look at the cheesemaking industry -- they use European microflora from caves.
Reply | Report Abuse | Link to thissounds like a reasonable hypothesis. perhaps another direction to focus in is on the massive injection of pesticides to control mosquitoes and west nile virus. i wanted so much to speak out, but there was so much hysteria, that no one was listening.
Reply | Report Abuse | Link to thiswe're seeing 'colony collapse' in bees as well, likely for similar reasons (and other pathogens involved there too).
we need to learn to support our food and ecological services webs - and seems we'll have to learn the hard way, 'cause roundup and DEET are still for sale and in use everywhere.
I was thinking that about 5 years ago the natural gas companys came up with a way to go down and over to get natural gas out.A lot more leases and buys on land at high dollars have been made right in the area these bats are being infected. Could this make a difference.
Reply | Report Abuse | Link to thisI was thinking that about 5 years ago the natural gas companys came up with a way to go down and over to get natural gas out.A lot more leases and buys on land at high dollars have been made right in the area these bats are being infected. Could this make a difference.
Reply | Report Abuse | Link to thisIt might sound like it is just population dynamics at work...however it is thought that the fungus was introduced from Europe. http://crittercatchersinc.com/critters/bats/White_Nose_Syndrome_Michigan.html
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