has devastated bat populations across the eastern United States during the past
six years, causing “the most precipitous wildlife decline in the past century
in North America,” according to biologists. And this relentless disease keeps
spreading into new areas.
In February 2006
some 40 miles west of Albany, N.Y., a caver photographed hibernating bats with
an unusual white substance on their muzzles. He noticed several dead bats. The
following winter, New York Department of Environmental Conservation biologists
documented what they called whitenose syndrome after seeing bats behaving
erratically, bats with white noses and a few hundred dead bats in several caves.
More than 6 million hibernating bats have died since then, making WNS the worst
wildlife health crises in memory.
Named for a
cold-loving white fungus typically found on the faces and wings of infected
bats, White-nose Syndrome causes bats to awaken more often during hibernation
and use up the stored fat reserves that are needed to get them through the
winter. Infected bats often emerge too soon from hibernation and are often seen
flying around in midwinter. These bats usually freeze or starve to death.
Mortality rates approaching 100 percent are reported at some sites.
brown bat with white-nose syndrome in Greeley Mine, Vermont, March 26, 2009.
Credit: Marvin Moriarty/USFWS
The appropriately named fungus
Geomyces destructans is the cause of deadly white-nose syndrome (WNS) in bats,
according to research published today in the journal Nature.
The study by U.S. Geological Survey scientists and partners, conducted at the
USGS National Wildlife Health Center in Madison, Wisc., provides the first
direct evidence that the fungus G. destructans causes WNS, a rapidly spreading
disease in North American bats.
"By identifying what causes WNS, this study will greatly enhance the
ability of decision makers to develop management strategies to preserve
vulnerable bat populations and the ecosystem services that they provide in the
U.S. and Canada," said Anne Kinsinger, USGS Associate Director of
During the study, 100 percent of
healthy little brown bats exposed to G. destructans while hibernating in
captivity developed WNS. Additionally, the study demonstrated that G.
destructans can be spread through contact between individual bats.
"While our study confirmed that G. destructans is spread bat-to-bat, it is
also important to note that virtually all pathogens, especially spore-producing
fungi, are spread by multiple routes," said David Blehert, USGS
microbiologist and an author of the study. "This is the reason that in an
effort to further control the spread of WNS, resource management agencies have
implemented universal precautions, including limiting human access to sensitive
environments occupied by bats, decontaminating equipment and clothing moved
between these environments, and restricting the movement of equipment between
Insect-eating bats provide economically valuable ecological services that are
estimated to save the U.S. agricultural industry alone billions of dollars each
year in insect pest-control expenses. However, U.S. bat populations have been
declining at an alarming rate since 2006, when white-nose syndrome first
appeared in New York State. Since then, the fungus G. destructans has spread
southward and westward and has now been found in 16 states and 4 Canadian
provinces. Bat declines in the Northeast, the most severely affected region in
the U.S., thus far have exceeded 80 percent.
This study was conducted by scientists from the USGS, University of
Wisconsin-Madison, Wisconsin Veterinary Diagnostic Laboratory, University of
Tennessee-Knoxville, New York Department of Environmental Conservation, the U.S.
Fish and Wildlife Service, Wisconsin Department of Natural Resources, and
found sick, dying and dead bats in unprecedented numbers in and around caves and
mines from New Hampshire south to Tennessee and in the Canadian provinces of
Ontario and Quebec. WNS is suspected in states as far west as Oklahoma. In some
hibernacula (caves and mines where bats hibernate in the winter) 90 to 100
percent of the bats are dying. In a hibernaculum, affected bats usually have
white fungus on their muzzles and other parts of their bodies. They frequently
lack adequate body fat to survive until spring. These bats may exhibit
uncharacteristic behavior such as moving to cold parts of the hibernaculum, and
flying during the day and during cold winter weather when the insects they feed
upon are not available.
White-nose syndrome has continued
to spread rapidly. At the end of the 2011-2012 hibernating season, bats with WNS
were confirmed in 22 states and five Canadian provinces:
New Brunswick, Canada
Nova Scotia, Canada
Prince Edward Island, Canada
The fungus that causes WNS,
Geomyces destructans, has been confirmed in two additional states:
Field observations have shown
that bats affected by WNS are characterized by some or all of the following: 1)
a white fungus that grows on the nose, ears, and wing membranes; 2) depleted
white and brown fat reserves by mid-winter; 3) a reduced capacity to arouse from
deep torpor; 4) an apparent lack of immune response during hibernation; 5)
ulcerated, necrotic and scarred wing membranes; and 6) atypical behavior causing
bats to emerge prematurely from hibernacula in mid-winter. Laboratory studies
have isolated a previously undescribed psychrophilic fungus, closely related to
Geomyces spp, from bats affected with WNS. This fungus grows on the skin (nose,
ears, and wing membranes) of hibernating bats, and laboratory studies revealed
it grows optimally at low temperatures characteristic of hibernacula. There is
histological evidence that the fungus sometimes penetrates the dermis,
especially in areas associated with sebaceous glands and hair follicles.
White-nose syndrome has been
found in a bat in France, according to an article published in the Centers for
Disease Control and Prevention's Emerging Infectious Diseases journal.
White-Nose Syndrome Fungus (Geomyces destructans) in Bat, France reports that a
bat found in March 2009 had the characteristic white fungus on its nose.
Laboratory testing confirmed that the fungus was the same as that found on bats
in nine northeast states where WNS has devastated bat populations.
WNS is transmitted primarily by
batto- bat contact. Biologists believe that people are inadvertently
contributing to the spread since some caves used by people have WNS-affected
bats, while other, nearby caves not used by people are not affected. Biologists
have found the fungus in caves that no longer have bats. The Service issued a
cave advisory in 2009 asking people to stay out of caves in affected states and
adjoining states. The advisory also asks cavers - when visiting caves outside of
the affected and adjoining states - to refrain from using clothing and gear that
has been used in affected and adjoining states. The Service hopes that
compliance with the cave advisory will help slow the spread of WNS until
researchers can determine how to stop it entirely. Many federal and state
agencies, organizations, and private individuals have closed caves on land they
own. As a precaution, biologists and researchers wear protective clothing when
visiting WNS-affected hibernacula, although there is no known human health risk
associated with WNS.
The future of bats
Until we discover how to
eradicate WNS, we face the real possibility of losing entire bat species. The
majority of bats dying in the Northeast has been little brown bats, one of the
most abundant bats in the United States. Other affected bat species include
tri-colored, northern long-eared, big brown, small-footed and endangered Indiana
bats. Cave myotis and endangered Virginia big-eared and gray bats may be
Losing huge numbers of bats could
affect the remaining bats’ ability to survive and adapt in the future through
loss of genetic variation. Insect-eating bats are voracious predators of insects
such as beetles, moths, aquatic flies and mosquitoes. The number of moths and
beetles that damage our forests and crops could increase as we lose the bats
that eat them. Increased pesticide applications might be needed to protect them
from insects like forest tent caterpillars. Backyard gardeners may see increases
in moth caterpillars or beetles preying on their gardens and may need to use
pesticides or handpick pests from their plants. The many people who enjoy
watching the silent flight of bats through the trees or over wetlands in the
night sky may no longer have that privilege. With lower numbers of bats, our
environment is already changing. We have no idea what our world could be like
with a complete absence of bats.
Frequently Asked Questions
1. What is white-nose syndrome?
Hibernating bats in the northeastern United States are dying in record numbers,
and we do not know the cause of the deaths. This wildlife health crisis,
white-nose syndrome, is named for the white fungus evident on the muzzles and
wings of affected bats. This affliction was first documented at four sites in
eastern New York in the winter of 2006-07. Subsequently, we saw photographs
taken in February 2006 of apparently affected bats at an additional site. WNS
has rapidly spread to multiple sites throughout the northeast. Researchers
associate WNS with a newly identified fungus (Geomyces sp.) that thrives in the
cold and humid conditions characteristic of the caves and mines used by bats.
The fungus could be responsible for the bat deaths, or it could be secondary to
the cause. Bats affected with WNS do not always have obvious fungal growth, but
they may display abnormal behavior within and outside of their hibernacula
(caves and mines where bats hibernate during the winter).
2. How is WNS is
transmitted? We believe that WNS is transmitted primarily from bat to bat. There
is a strong possibility that it may also be transmitted by humans inadvertently
carrying the causative agent from cave to cave on their clothing and gear.
3. Where has WNS been observed?
Biologists and/or cavers have documented WNS in bat hibernacula in New
Hampshire, Vermont, New York, Massachusetts, Connecticut, New Jersey,
Pennsylvania, West Virginia and Virginia. We expect this list of states to
increase over time.
4. What are signs of WNS? Bats
may lose their fat reserves, which they need to survive hibernation, long before
the winter is over. They often leave their hibernacula during the winter and
die. As winter progresses, we find increasing numbers of dead bats in the
affected locations. WNS may be associated with some or all of the following
unusual bat behavior: n White fungus, especially on the bat’s nose, but also
on the wings, ears or tail; n Bats flying outside during the day in temperatures
at or below freezing; n Bats clustered near the entrance of hibernacula; and n
Dead or dying bats on the ground or on buildings, trees or other structures.
Hibernating bats may have other white fungus not associated with WNS. If a bat
with fungus is not in an affected area and has no other signs of WNS, it may not
5. What should you do if you find
dead or dying bats in winter or early spring, or if you observe bats with signs
of WNS? n Contact your state wildlife agency, file an electronic report in those
states that offer this service, e-mail U.S. Fish and Wildlife Service biologists
at WhiteNoseBats@fws. gov, or contact your nearest Service field office (find
locations at http:// www.fws.gov/northeast/offices. html) to report your
potential WNS observations. n It is important to determine the species of bat in
case it is a federally protected species. Photograph the potentially affected
bats (including close-up shots if possible) and send the photograph and a report
to your contact (above). n If you need to dispose of a dead bat found on your
property, pick it up with a plastic bag over your hand or use disposable gloves.
Place both the bat and the bag into another plastic bag, spray with
disinfectant, close the bag securely, and dispose of it with your garbage.
Thoroughly wash your hands and any clothing that comes into contact with the
bat. See a short instructional video on our WNS Web site. n If you see a band on
the wing or a small device with an antenna on the back of a bat (living or
dead), contact your state wildlife agency or your nearest Service field office
as these are tools for biologists to identify individual bats.
6. What species of bats are
affected? Tri-colored, little brown, northern long-eared, big brown,
small-footed and Indiana bats have died from WNS. Big brown bats are typically
found in lower numbers in the affected sites, and few have been found with the
signs of WNS.
7. What are the Service and other
federal and state agencies doing to find the cause and a cure for WNS? An
extensive network of state and federal agencies is working to investigate the
source, spread and cause of bat deaths associated with WNS and to develop
management strategies to minimize the impacts of WNS. The overall WNS
investigation has three primary focus areas: research, monitoring/management and
outreach. For example, we are conducting winter surveys to document and track
affected sites, working with the caving community and local cave owners to
target potential sites for surveys and protective measures, and securing funding
to identify and fund research on the spread and management of WNS. In addition,
the Service has a Web page as a central repository for up-to-date information
and links to other relevant Web sites.
8. What should cavers know and
do? The Service and the states request that cavers observe all cave closures and
advisories and avoid caves, mines or passages containing hibernating bats to
minimize disturbance to the bats. The Service asks that cavers and cave visitors
stay out of all caves in the affected states and adjoining states to help slow
the potential spread of WNS. Local and national cave groups have also posted
information and cave advisories on their Web sites.
9. Does WNS pose a risk to human
health? Thousands of people have visited affected caves and mines since WNS was
first observed, and there have been no reported illnesses attributable to WNS.
We are still learning about WNS, but we know of no risk to humans from contact
with WNS-affected bats. However, we urge taking precautions and not exposing
yourself unnecessarily to WNS. Biologists and researchers use protective
clothing when entering caves or handling bats in the Northeast.
10. What is the effect of WNS on
bats? Some 400,000 bats have died from WNS, and there seems to be no end in
sight. We have seen 90 to 100 percent mortality of bats (primarily little brown
bats) at several hibernacula in New York, Massachusetts, Connecticut and
Vermont. However, there may be differences in mortality by site and by species
within sites. The endangered Indiana bat hibernates in many of the affected
sites. We are closely monitoring Indiana bat populations in many hibernacula
and, to the extent possible, in their summer maternity colonies. In New York and
New England, we think as a result of WNS, winter counts of Indiana bats have
declined. During the winter of 2008-2009 we conducted our biennial rangewide
winter counts of Indiana bats. Early results from New York report significantly
fewer bats. In addition to the Indiana bat, WNS has reached sites that contain
the endangered Virginia big-eared bat. While no Virginia big-eared bats have
exhibited signs of WNS yet, we are closely monitoring this species.
11. Is global climate change a
possible cause of WNS? While the many possible causes of WNS are being
investigated, there is currently no evidence to support a link between climate
change and WNS. Microclimates in caves and mines where bats hibernate have been
stable during the time period when WNS emerged, and there are no data indicating
changes in insect prey populations in the affected region. Potential impacts of
global climate change will continue, however, to be monitored as part of the
Credit: U.S. Fish
and Wildlife Service, Bat Conservation International, Smithsonian Institute, DC
Comics, ABC,The Oakland Zoo
compiled from The British Antarctic Study, NASA, Environment Canada,
UNEP, EPA and other sources as stated and credited Researched by Charles
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