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The Past, Present and Future of White-Nose
Syndrome in Bats
Abstract
White-nose syndrome (WNS) is an invasive fungal disease that has killed millions of bats since it wasrecently discovered in New York. The fungus colonies and deteriorates the tissues of hibernating bats
leading to degradation of water balance! fre"uent arousals from tor#or! accelerated fat store de#letion and
eventually death. $onsidering the e%ceedingly high mortality rate (& ') and ra#id s#read! which as of
s#ring *+, WNS has been confirmed in twenty-si% states and five $anadian #rovinces! its #roected that
once common bat s#ecies will soon become e%tinct from affected North /merican regions unless new
breakthroughs in research and intervening conservation efforts occur. These insectivorous bats #lay a
crucial role in #est control. 0t has been suggested if WNS continues to devastate these keystone s#ecies!
the agricultural industry will suffer great losses.
Christopher D. Wisnies!i
Southern Connecticut State "ni#ersity
Department of Bio$o%y
Sprin% &'()
Tab$e of Contents
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 1
0ntroduction4444444444444444....##. *-5
Pseudogymnoascus destructans.................................... ##. 5-6
Pd introduction to North /merica44444444.##. 6-,
Pd transmission444444444444444..##. ,-7
Pd incubation44444444444444...4..#. 7
WNS detection444444444444444...##. 7-+
Pd infection4444444444444444....##. +-++
1otential recovery from WNS444444444...##. ++-+*
1hysiological disturbances associated with WNS4....##. +*-+5
3ehavioral disturbances associated with WNS444.##. +5-+,
1o#ulation devastation444444444444...##. +,-+8
9ooking forward44444444444444....##. +8-*
Why bats are im#ortant44444444444.4.#. *
:cological im#ortance of bats444444444...##. *-*+
:conomic im#ortance of bats4444444444##. *+-**
3ats as model s#ecies4444444444444#. **
$onservation444444444444444.4.##. **-*;
0n closing44444444444444444...#. *;
/cknowledgements4444444444444...#. *8
owe $averns in
u#state New York in *; (3lehert et al. *'). The #sychro#hilic fungus which causes WNS!
Pseudogymnoascus destructans ( Pd ) (3lehert et al. *'? @argas et al. *'? 9orch et al. *++?
Warnecke et al. *+*? Ainnis B 9indner! *+5)! develo#s on bats as a filamentous white growth
on wings! mules and ears. While fungal conidia growth around the mule of bats is one of the
most cons#icuous signs of WNS! bat wing membranes are often the most afflicted regions by Pd
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 2
due to this region containing the largest surface area of e%#osed skin (Aeteyer et al. *'? $ryan
et al. *+). Pd s#ores colonie these su#erficial tissues and begin to deteriorate the e#idermis
and dermis (Aeteyer et al. *'? $ryan et al. *+). This destruction allows for further
e%#ansion of the fungal colony into healthy! su#erficial and dee# tissue leading to a #lethora of
#hysiological and behavioral disru#tions which ultimately cause mortality ($ryan et al. *+?
Turner!
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 3
Service! *+6). These high mortality rates over re#eated hibernation cycles have led to massive
#o#ulation declines of once common native bat s#ecies.
The devastation of North /merican bat s#ecies by WNS is un#recedented. This is thelargest wildlife e#idemic ever recorded and it #oses a threat of regional e%tinction to multi#le bat
s#ecies in the coming years (2rick et al. *+? 9angwig et al. *+*). This review aims to bring
together available data on WNS in North /merica into one convenient re#ort in ho#es to
generate new directions for habitatFs#ecies management #ractices as well as aid conservation
strategies and future research. /s 0 advocate the dire need for conservation and continued
research efforts! 0 ho#e to increase awareness! educate others! and encourage more individuals to
become involved to hel# bring our local bat s#ecies back from the brink of e%tinction! thus
#reserving our natural history.
Pseudogymnoascus destructans
The causative agent of white-nose syndrome (WNS)! Pseudogymnoascus destructans
( Pd ? formerly classified Geomyces)! is a #sychro#hilic fungus found to grow between G-*G$
(3lehert et al. *'? @argas et al. *'? 9orch et al. *++? Warnecke et al. *+*? Cerant et al.
*+*? Ainnis B 9indner! *+5). While Pd grows o#timally between +*.,G-+,.7G$! it has been
found Pd cannot grow at tem#eratures as low as -+G$ or as high as *,G$! with +'G-+'.7G$ being
the a##ro%imate u##er growthFtem#erature limit (3lehert et al. *'? $haturvedi et al. *+?
Cerant et al. *+*). Pd re#roduces ase%ually and is characteried by the #resence of coloniing
fungal hy#hae with distinctive asymmetrically curved conidia (3lehert et al. *'? @argas et al.
*'). @ross identification of Pd on bats is #ossible due to the #resence of white filamentous
growth a##earing on wings! mules and ears (3lehert et al. *'? @argas et al. *') or as a
filmy substance on wings (Aeteyer et al. *'). 1erha#s the most indicativeFcharacteristic sign
of the disease on bats in the field is the #resence of white conidia growth on the mule! which
also contributed to the creation of the Hwhite-noseI designation of the disease (3lehert et al.
*'? $ryan et al. *+).
Pd introduction to North America
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 4
/s of s#ring *+,! WNS has been confirmed in hibernacula across twenty-si% states and
five $anadian #rovinces (=S 2ish B Wildlife Service! *+6). 0n addition! Pd is also currently
#resent in two additional states where the disease has yet to be confirmed in bats. >ow did Pd
and WNS come to be in North /mericaJ Cia e%#erimentation! North /merican bat s#ecies were
shown to be e"ually susce#tible to strains of Pd from both North /merica and :uro#e. This
allowed Warnecke et al. (*+*) to su##ort the novel #athogen hy#othesis in which it is believed
that Pd was accidentally introduced from :uro#e where Pd and WNS are #resent! but without the
associated mass mortality #resent in North /merican bat s#ecies. The introduction of Pd on
naKve #o#ulations of North /merican bats is believed to be the driving force behind the
subse"uent mass mortality (Warnecke et al. *+*). 0n fact! Pd remained overlooked on the bats
of :uro#e until the recent e%#losion of WNS in North /merica nine years ago (Warnecke et al.*+*). Warnecke et al. (*+*) suggest that bats with Pd in :uro#e dis#lay more well-ada#ted
#hysiological and behavioral res#onses com#ared to the disorderly res#onses of North /merican
s#ecies? this accounts for the absence of mass mortality of bats in :uro#e com#ared to North
/merica. This work also su##orts Wibbelt et al. (*+) who mention thatD +.) Pd may have been
#resent and coevolved with :uro#ean bats leading to an immunological or behavioral resistance
or tolerance to form in regards to the fungus! or that *.) Aicrobial flora #resent on bats or in
hibernacula in :uro#e may have coevolved with Pd leading to its non#athogenic role. 3oth
suggestions could e%#lain why there is such a contrast in mortality cases between the two
continents. 0t would be interesting to determine the effects of the North /merican strain of Pd on
:uro#ean bat s#ecies. 2urther testing could #otentially fill ga#s about the differences in
#athogenicity between the two continents and hel# to su##ort an e%#lanation as to why :uro#ean
bats are ca#able of living with the fungus. 2urthermore! 0 hy#othesie the culturing of the skin
microbiome of :uro#ean bats may #rovide useful data in regards to #otential naturally occurring
microbes which may #ossess antifungal #ro#erties similar to the North /merican bats in the >oyt
et al. (*+,) study which is discussed later. This could e%#lain the lack of mortality in :uro#ean
bats and #rovide droves of useful data which could have large im#lications for North /merican
bats! given sufficient testing.
The novel #athogen hy#othesis was further su##orted by 9orch et al. (*+5) who were
able to dis#rove the hy#othesis that a less virulent strain of Pd was always #resent in North
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 5
/merica! until a mutation and subse"uent increasing #athogenicity emerged leading to the
current WNS outbreak. 9orch et al. (*+5) screened collected sediment sam#les from
hibernacula both inside and outside of WNS affected regions and isolated LN/ from these
sam#les. Ef the *', sediment sam#les screened! +8 were #ositive for Pd ! all of which came
from within WNS affected regions? no Pd was discovered in sam#les from non-affected regions
(9orch et al. *+5). These findings #rovide evidence against an endemic strain of Pd being
#resent in North /merica #rior to the WNS outbreak and instead su##ort the novel #athogen
hy#othesis suggesting Pd was accidently introduced from :uro#e to North /merica.
Pd transmission
/lthough #ossible modes of transmission for WNS are still being investigated! some have been well su##orted. WNS can be transmitted among bats via direct contact between individuals
or via direct contact between bats and hibernaculaFenvironment (9orch et al. *++? 9orch et al.
*+5? >oyt et al. *+6? 3ernard et al. *+,). Some early indications for bat to bat transmission
of WNS comes from documentation of infection at multi#le sites in 1ennsylvania! which were
initially shielded from humans and #o#ulation management before WNS was detected! still! the
resulting infection was hy#othesied to have been introduced by infected bats (Turner!
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 6
Pd can also be transmitted via direct contact between bats and hibernaculaFenvironment.
0t is understood that Pd has the ability to survive in hibernacula in the absence of bats serving as
a reservoir for new infections. 9orch et al. (*+5) detected live Pd in 8 out of +6 hibernacula
sites during the late summer when bat #o#ulation densities were low. 0n this same study!
sediment sam#les from the sites were tested and live Pd was found in sites where bats had not
been #resent from a few months! to u# to two years! indicating long term #ersistence of the
fungus is #ossible given suitable hibernacula conditions. >oyt et al. (*+6) also showed Pd can
#ersist in environments in the absence of a host. They isolated Pd from bats! and stored #ure
isolates in an incubator at ,G$ and 5-6 relative humidity for ,-; years. /fter this time! Pd
from si% of the nine original isolates grew on new media! confirming enough viable conidia
remained over this e%tended #eriod of time. This demonstrates that even after long termlaboratory storage Pd can grow in the absence of a host! suggesting that environments
contaminated with Pd conidia can continually infect bats. /dditionally! its suggested that the
#resence of other microbes! inducing com#etition! and humidity may affect Pd survival in
natural conditions (>oyt et al. *+6).
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 7
the e%#eriment all showed consistent concentrations of Pd which varied with the seasons.
9angwig et al. (*+,/) found no su##ort for the hy#othesis that birth #ulses drive seasonality.
They found the #revalence of Pd dro##ed during the summer months when births occurred. 0t
was also found that seasonal changes in habitat use showed low transmission and infection
intensity until #rolonged tor#or was em#loyed by bats! meaning another factor had to have been
driving seasonality (9angwig et al. *+,/). 9angwig et al. (*+,/) found that hibernation was
the dominant factor driving transmission and #athogenicity. 1rolonged tor#or brought about
close to + of individuals becoming infected. $ontact rates during this time are unknown! but
they could influence transmission. 0t is understood that the body tem#erature of bats during this
time! also within the range re"uired by Pd to thrive! is what allows for such an e%#losion of
#athogen growth and transmission (9angwig et al. *+,/). The influence of Pd on hibernating bats during this time is ma%imied? as when infection #eaks! #o#ulations are usually at their
lowest concentrations which brings about the most drastic im#lications of WNS. Everall! the
seasonal timing (winter hibernation) of transmission and #athogenicity allow for the most
damage to be dealt to bat s#ecies! while at the same time! seasonal timing affects Pd s#read due
to the #eriods of low mobility demonstrated by the hibernating bat hosts (9angwig et al. *+,/).
The researchers hy#othesied that if transmission rates were com#arable in autumn as they are
during winter! that Pd s#read and infectiousness would be much higher than we currently witness
(9angwig et al. *+,/).
0t should also be noted that Pd can be transmitted via humans who come in contact with
either bats or hibernacula. Pd conidia can be trans#orted on e"ui#ment and clothes! increasing
the likelihood of Pd s#read and thus WNS occurrence (Turner! oyt et
al. *+6). 0n fact! this form of transmission is conducive with the novel #athogen hy#othesis and
is believed to be how Pd and WNS were introduced to North /merica. >oyt et al. (*+6)
suggested that Pd may be able to survive outside of hibernacula (on e"ui#ment! clothes! etc.) if
such materials are stored in cool dry #laces.
Pd incubation
9orch et al. (*++) were able to "uantify the incubation #eriod of Pd in bats! how much
time #assed until WNS became characteristically #resent and how long until mass mortality of
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 8
#o#ulations took #lace. Through e%#erimental infection with Pd, and subse"uent histological
e%amination they found that inoculated bats develo#ed diagnostic lesions for WNS 75 days after
being treated and all were #ositive for WNS when the trial was terminated at the +* day mark.
9arge scale mortality among infected bats was not witnessed! but this was due to the short term
of their e%#eriment. The study was able to su##ort data on the develo#ment of WNS in wild
bats. 0n wild #o#ulations! WNS lesions are initially detected in late Se#tember #rior to the onset
of long term hibernation. Aass mortality can begin in late Manuary and #eak in Aarch (9orch et
al. *++). This demonstrates that mortality from WNS doesnt begin until a##ro%imately +*
days from when bats begin long term! winter hibernation in which cold tem#eratures necessary
for Pd to thrive occur! also mortality #eaks at about +7 days? this accounts for why mass
mortality wasnt observed in their e%#eriment which was terminated at the +* day mark beforethe disease could #rogress further to induce mortality.
WNS detection
White fungal growth found on the mules! wings and ears of bats are characteristic signs
of WNS (3lehert et al. *'? @argas et al. *'). These gross fungal lesions can be indicative of
WNS? however they dont always lead to a diagnosis. @ross lesions can be damaged or lost
when bats are #re#ared and trans#orted from hibernacula to laboratory settings! making further
e%amination im#erative for confirmation of the disease (Aeteyer et al. *').
>isto#athologic e%amination is considered the most effective way to confirm WNS in an
infected organism (Aeteyer et al. *'). /lterations in skin of infected bats can include #atches
of rough skin! loss of sheen on glabrous skin! irregular #igmentation and tears in wing
membranes (Aeteyer et al. *'). Through microsco#y! detection of Pd hy#hae and conidia on
infected tissue is #ossible. The surface area of tissue needs to be ma%imied! which can be
accom#lished by fi%ing longitudinal sections of tissue in + neutral buffered formalin and
embedding trimmed surfaces to maintain the #osition of fungus in regards to dermal structures
(Aeteyer et al. *'). Aeteyer et al. (*') found staining useful in detecting the fungus?
#eriodic acid-Schiff stain was shown to be the most effective at detecting non-#igmented fungal
hy#hae and conidia. H$u#-likeI e#idermal erosions found via microsco#y of wing membranes
are characteristic of WNS and are often filled with hy#hae (Aeteyer et al. *'). The fungus can
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 9
be found continuing to invade underlying connective tissue and can encom#ass the full thickness
of the wing membrane. 0n regards to the mule! hy#hae invade hair follicles! sebaceous glands!
a#ocrine glands and connective tissue (Aeteyer et al. *'). Aeteyer et al. (*') also note bats
with damaged wings collected from outside hibernacula showed severe inflammation in
accordance with the fungal infection. Su##urative dermatitis with folliculitis! edema! infiltrates
of macro#hages! and serocellular inflammatory crusts with hy#hae were also noted histological
changes found by Aeteyer et al. (*'). The necrosis and im#airment of wing membranes can
be very #roblematic to bats and will be discussed in coming sections.
>istologic e%amination! a very effective diagnostic tool! often re"uires euthanasia in
order to ac"uire enough suitable tissue for testing. When considering the soaring mortality rates
associated with WNS! a non-lethal diagnostic tool would be most advantageous for field and
laboratory research.
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 10
The culture techni"ue used to detect Pd is #robably the least efficient diagnostic tool of
those mentioned thus far! but its not without its benefits. This techni"ue re"uires taking an
infected tissue sam#le! growing the microbial elements of the sam#le on media and then
identifying the given organisms and their mor#hology under microsco#e in order to determine if
Pd is #resent (9orch et al. *+). The culture method has been shown to have a diagnostic
sensitivity of ,6! com#ared to 1$
absent in infected tissues! although this is most likely due to the su##ression of immune
res#onses associated with hibernation (Aeteyer et al. *'? *++). /s the infection #rogresses!
Pd a##ears as hy#hae filled! cu#-like lesions within the e#idermis! which continue to invade and
degrade sebaceous and a#ocrine glands! hair follicles! connective tissue! lym#hatic vessels and
muscle fibers in infected areas (Aeteyer et al. *'? $ryan et al. *+). 0nfarction has been
observed in wing membranes and although Pd is not vasculotro#ic it a##ears to have an effect on
blood flow to certain regions of the wings ($ryan et al. *+).
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 11
than wing damage associated with HnormalI environmental occurrences (
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 12
. These arousals then lead to dehydration and further de#letion of fat
stores. /s the Pd invasion #rogresses dee#er! reaching connective tissue! additional water and
electrolyte loss occurs. Lehydration is then intensified leading to additional arousals from
tor#or. This all creates a #ositive feedback loo# envelo#ing arousal! water loss! electrolyte loss
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 13
and energy use. This feedback loo# continues until all com#ensatory mechanisms and energyFfat
reserves are drained! leading to death! however! if com#ensatory mechanisms and energyFfat
reserves remain until the s#ring emergence from hibernation then its #ossible for the Pd
infection to recede and for the bat to #ossibly recover.
This model is the first of its kind and includes testable hy#otheses which should #rovide a
basis for future research and should #rovide crucial knowledge of disease #rogression that will
aid conservation #ractices in the fight against WNS.
Beha#iora$ disturbances associated ith WNS
WNS is also known to bring about behavioral disturbances in hibernating bats. The most
debated behavioral disturbance in bats due to WNS is arousal from tor#or. Tor#or (a form of
dormancy! similar to hibernation! but occurring over much shorter #eriods in which body
tem#erature and metabolic rates are reduced) can last from #eriods of days to weeks in bats
(@eiser! *6?
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 14
2urthermore! Turner et al. (*+,) #rovide evidence that synchroniation of arousals
reflects disturbances of tor#id bats by infected cons#ecifics. They discuss that hibernating bats
are highly susce#tible to disturbance! making arousal more likely if actively infected bats
continue to come in contact with tor#id individuals. /s hibernation and infection #rogresses this
increased contact brought about a Hcascade effectI of increasing arousals over time (Turner et al.
*+,). Nonetheless! the high energetic demands of fre"uent arousals from tor#or remain and are
still instrumental in the de#letion of hibernating resources and subse"uent mortality.
WNS is associated with other abnormal behaviors in hibernating bats as well. While
winter flying! s#ecifically daytime winter flying! in healthy bats is not considered abnormal
(>endricks B >endricks! *+)! bats sus#ected of #otentially having WNS have been observed
#artaking in e%cessive flying ($ryan et al. *+)! unusual daytime flying! uncoordinated flying
including collisions into nearby trees! buildings! etc. (Turner!
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 15
(*+6) mention this reduced clustering being a tenet of Hsickness behaviorI in which it is more
advantageous for individuals in infected hibernacula to remain isolated from one another to
reduce the s#read and other unfavorable side effects of the given disease. This led Turner et al.
(*+6) to identify that reduced clustering and isolation could be an ada#tive res#onse by bats
with WNS to reduce the s#read of Pd . The behavioral study of bats in laboratory and wild
settings is often difficult? although some observations and e%#eriments have been com#leted
more data and e%amination into the behavioral disturbances of bats with WNS is needed to
clarify com#eting results and establish well-su##orted e%#lanations. 0t would be interesting to
observe if any additional altered or ada#tive behaviors are occurring in bat #o#ulations in states
near the e#icenter of the WNS outbreak. 3ats of this region have shown #ersistence in res#onse
to WNS before (
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 16
de#endent on five scenarios from an initial #o#ulation of ;., million bats. /s such! they e%#ect a
'' chance of regional e%tinction of M. lucifugus by the year **;? annual declines would need
to be less than , #er year for a noticeable reduction in the chance of e%tinction occurring over
one hundred years. 0ts im#ortant to note that these #redictions were derived for the #reviously
most abundant bat s#ecies in North /merica! M. lucifugus. 0f the most #lentiful bat s#ecies in
North /merica is e%#ected to be regionally e%tinct in WNS affected areas by **; its most
likely that #re-WNS endangered bat s#ecies like M. sodalis and M. grisescens or newly listed
endangered bat s#ecies M. septentrionalis will also become e%tinct. There is evidence of
interannual survival of M. lucifugus in New :ngland states as some colonies seem to #ersist
(owever! as the once common little brown bat is #ro#osed for listing on
the endangered s#ecies list in $onnecticut! its doubtful if #o#ulations will ever recover to #re-WNS levels.
1o#ulation forecasting has also been researched by 9angwig et al. (*+*). They
estimated #o#ulation growth rates of si% bat s#ecies both before and after the outbreak of WNS
based on data from +* regional #o#ulations. /fter incor#orating changes in roosting behavior!
environmental variation and #o#ulation densities into their mathematical models! 9angwig et al.
(*+*) found that #rior to WNS all of their tested s#ecies showed increasing #o#ulation growth.
>owever! in years following WNS discovery! #o#ulation growth rates for four s#ecies showed
significant decline ( M. lucifugus, M. sodalis, M. septentrionalis B P. subflavus)! while the
remaining two s#ecies showed neither growth nor decline ( E. fuscus B M. leibii) (9angwig et al.
*+*). Everall! all growth rates were much lower #ost-WNS discovery than in #re-WNS years!
and &*8 of the e%amined bat #o#ulations (5* of +*) became e%tinct (9angwig et al. *+*).
3ased on their results and continued modeling M. septentrionalis, M. sodalis and M. lucifugus
are #redicted to go e%tinct.
/lves! Terribile B 3rito (*+6) have also conducted modeling to e%amine the #otential
increasing s#read of WNS as well as its continued effect on bat #o#ulations. They used
ecological niche modeling (:NA) to #redict #otentially new geogra#hic regions which may
become afflicted by WNS. This data would be of great use to such regions as it would allow
them to take the necessary #recautions and im#lement strategies to effectively deal with the
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 17
fungus and #rotect their local bat #o#ulations. The :NA took into account variations of
tem#erature! #reci#itation! elevation and land classes when modeling #otential regions Pd could
infect and survive in. The generated ma# of #otential s#read dis#layed the current distribution of
Pd (/lves! Terribile B 3rito! *+6). The ma# also showed regions susce#tible to Pd which
#resently are unaffected! including! coastal regions of the Northeastern =.S.! the Aississi##i
basin region and the
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 18
oyt et al. (*+,) also shows #romise. They assessed if bacteria from the
bats skin microbiome can inhibit Pd growth. >oyt et al. (*+,) demonstrated that these naturally
occurring bacteria canD +.)
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 19
among bat #o#ulations in the #resence of Pd and also #rovides evidence that immuniing bats
may #rovide #rotection from Pd (Mohnson et al. *+,).
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 20
due to WNS is not combated in the coming years. 0f WNS continues to devastate these keystone
s#ecies! affected regions will suffer immense losses.
owever! some governing bodies and related #olicy makers! as well as most of the general
#ublic! arent as #rivy. 3at advocacy will highlight the im#ortance of this grou# of animals from
economic! ecological and natural history #ers#ectives! motivate research and #erha#s raise vital
funding thus aide new! innovative conservation #ractices. $onsidering the re#ercussions of a
loss of bats on this scale! it is wise to advocate in government! #rofessional and #ublic venues so
#eo#le will know what WNS is and what affects it will have! not only on our bat #o#ulations! but
in many as#ects of #eo#les lives if its s#read and subse"uent mortality #ersist.
co$o%ica$ importance of bats
/gricultural #ests of the arthro#od variety have been known to u#set farmlands all across
North /merica. The re#ercussions caused by such arthro#ods can destroy entire fields of cro#s
and leave farmers without food or income to su##ort their families. =sually! #esticides are used
to combat such #ests! but #esticides have unwanted effects! such as the contamination of foods!
human and non-human organisms and ecosystems (/ktar! Sengu#ta B $howdhury! *'). 0n
some cases contamination can cause death or other serious #hysiological com#lications in human
and non-human organisms! making #esticide use controversial and #otentially haardous to those
e%#osed (/ktar! Sengu#ta B $howdhury! *'). 0n addition to these unwanted effects! it has
been estimated that over 6 s#ecies of cro#-#est insects have develo#ed resistance to commonly
used #esticides! creating an even greater challenge in the realm of #est control (un et al. *++).
:nter the insectivorous bat. The bats #lagued by WNS in North /merica are all
tem#erate! insectivorous s#ecies. They o##ortunistically feed on a variety of insects from
different environments including forests! grasslands! farmlands! etc. (un et al. *++). Luring
winter hibernation consum#tion slows! but activity and feeding still occur and are more common
in bats which hibernate in thermally unstable microhabitats (Lunbar! Whitaker! Mr. B
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 21
body mass) of insects #er night to account for energy e%#enditures and Whitaker (+'',)
determined that a colony of +, big brown bats ( E. fuscus) in the Aidwest can annually consume
a##ro%imately +.5 million cro#-#est insects. These numbers su##ort what many #eo#le have
known for centuries! that insectivorous bats are a natural form of #est control.
/nthony and un (+'88) and urta et al. (+'7') found that the little brown bat can
consume between 6 g P 7 g of insects on an average night. The little brown bat is also one of the
most! if not the most affected bat in regards to WNS. /s of *+! 3oyles B Willis e%tra#olated
this 6 g P 7 g #er night consum#tion rate during the active season to the estimated ,! bats
that died from WNS and estimated that between 55 and ;; metric tons of insects were no
longer being consumed in WNS regions. Now multi#ly that number by the estimated seven
million bats that have died as of s#ring *+,? between 6!;* and '!*6 metric tons of insects are
no longer being consumed in WNS regions. 0magine the increased use of #esticides in affected
regions to combat these insects. / ob bats were #erforming naturally #re-WNS with no
unwanted side effects will now! in the #ost-WNS world! rely u#on chemicals which have the
chance to devastate entire ecosystems if used im#ro#erly. The realiation of the im#acts WNS is
having on our natural world is enough to leave one s#eechless.
conomic importance of bats
/fter acknowledging the work of /nthony B un (+'88)! urta et al. (+'7')! Whitaker
(+'',) and 3oyles B Willis (*+) its easy to understand the im#acting role bats #lay in regards
to insect su##ression. :conomic estimates of the role bats #lay in #est control are still not fully
understood! however some #ublished work has estimated the #otential economic losses the
agricultural industry will suffer from the mass mortality of bats with WNS. 3oyles et al. (*++)
estimate the value of bats to the agricultural industry to be a##ro%imately Q**.' billion #er year.
This estimate was derived with the reduced costs of #esticide a##lications in mind! but it does
not include certain factors like #redation of insects in forest ecosystems! or the secondary effects
of #redation on insects (reducing the #otential for #esticide resistant insects to thrive) (3oyles et
al. *++). 0magine if WNS moves into the Hbread basketI region of the =nited States. WNS has
been confirmed in the Aidwest already and further s#read could be detrimental to the
agricultural industry not to mention the bat s#ecies of the region. The Q**.' billionFyear
S$S= 3iology
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 22
estimated by 3oyles et al. (*++) could easily be doubled over the s#an of a year if WNS were to
move into this region.
Bats as mode$ species
/lthough its sometimes difficult to "uantify the im#act of bats to academia and research!
these flying mammals surely have an e%traordinary value which needs to be recognied.
Numerous fields have e%#erienced advances from the study of bats. Ene of the largest
contributions from the study of insectivorous bat s#ecies! some of which are now #lagued by
WNS! to the educational and research worlds has been the study of bat echolocation and
locomotion (un et al. *++). The study of such functions has #rovided advances in fields
related to sonar systems! biomedical ultrasound! wireless communication and 3/TA/CS (bat-like motoried aerial vehicles) (un et al. *++). 1eo#le enoy vilifying bats. 0f #eo#le were to
understand the influence bats! es#ecially the insectivorous bats #lagued by WNS! have on our
natural world! culture! education and technological advancements they would surely oin the
countless researchers and wildlife enthusiasts who are des#erately trying to understand and
combat WNS.
Conser#ation
/s has been discussed! WNS is obliterating our insectivorous bat #o#ulations (2rick et al.
*+? 9angwig et al. *+*? Cerant et al. *+6).
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 23
their #art too. 3at $onservation 0nternational assists in allocating funds and other resources to
hel# in studying and finding solutions to WNS.
/ real world a##lication to HcureI bats of WNS that can s#an twenty-si% states has yet to be #erfected. Still! in the nine years since the discovery of WNS in North /merica! the scientific
community has learned much about the disease and #roduced co#ious amounts of data bringing
us ever closer to a viable solution. >owever! resources are still needed. The vigilance and
resolve of the #rofessionals researching WNS needs to be instituted in the general #ublic. Ene of
the ho#es 0 have is to bring the WNS discussion to the forefront and create a sense of urgency
among the #ublic. With more #ublic involvement not only will more conservation efforts occur
and more funding be raised! but #olicy-makers hearing from their advocating constituents will
ho#efully do more to allocate resources to vital research already in #rogress.
Liscussions among the scientific community about the res#onse to wildlife diseases are
in #rogress. 9angwig et al. (*+,3) have develo#ed conservation res#onses! broken into four
stages! based on the #athogen invasion #rocess. The first stage of the #athogen invasion #rocess
is #re-arrival. 9angwig et al. (*+,3) stress that the first goal in this stage should be to
determine the threat #osed by a given disease to the #articular region(s)? then #recautions should
be taken and interventions im#lemented to reduce the #robability of disease introduction.
=nderstanding #otential #athways of introduction and im#lementing a ra#id! #roactive res#onse
are vital in this stage. 0f necessary! biosecurity should be im#lemented to "uarantineFrestrict
access to areas at high risk for infection before a large scale outbreak occurs (i.e. cave B mine
closures in res#onse to WNS) (9angwig et al. *+,3). :stablishing communication and
s#reading awareness are also crucial. 0t is of the u#most im#ortance to have the #ublic aware
and involved.
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 24
0nvasion front is followed by the e#idemic stage in which #athogen establishment has
occurred within a region. The main goal of this stage should focus on reducing im#acts from the
disease on local #o#ulations and environments (9angwig et al. *+,3). Ways of reducing
im#acts include! but are not limited to! vaccinations! treatment with chemical or biological
agents! habitat mani#ulation and augmenting demogra#hic rates (reducing natural #redation! etc.)
(9angwig et al. *+,3). >ost resistance or tolerance may be facilitated from im#lementing the
above measures and could #rove worthy once s#read among the given #o#ulation and #otentially
#assed onto subse"uent generations? in the case of WNS! the work of 2rank et al. (*+6) and
>oyt et al. (*+,) shows great #otential in this area of study.
The last stage is known as the established stage in which a given disease has created a
stronghold over a greater area and is currently afflicting local #o#ulations. 0n this stage the
#rotection and restoration of local #o#ulations is of the u#most im#ortance! both of which should
be im#lemented in any reasonable way (9angwig et al. *+,3). 2urthermore! four additional
actions are of great im#ortance among all of the aforementioned stages. The actions includeD +.)
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 25
unusual bat behavior in affected regions. /bnormal! daytime flying from Lecember to Aarch
when bats should be hibernating can be indicative of WNS and should be re#orted to state
environmental agencies immediately ($ryan et al. *+). 3y re#orting such incidences!
communication is ke#t o#en as to new #otential WNS occurrences and agencies can direct a
more ra#id! real-time res#onse.
0ndividuals also want to avoid #otentially s#reading Pd . /s discussed earlier! evidence
su##orts that Pd and WNS were introduced from :uro#e! most likely inadvertently via humans
(Warnecke et al. *+*? 9orch et al. *+5). Pd has also been found to survive in hibernacula! on
clothes and e"ui#ment given the right environmental conditions making it absolutely necessary
that cavers and others do their best to avoid contact with Pd (Turner! oyt et al. *+6). /n individual can avoid contact with the fungus by s#orting
#rotective outerwear when visiting hibernacula! decontaminating after visiting and if #ossible!
avoid infected hibernacula all together. / national WNS decontamination #rotocol was
develo#ed by multi#le agencies which should #rove useful to field researchers and other wildlife
enthusiasts and can be found on WhiteNoseSyndrome.Erg (=.S. 2ish and Wildlife Service! *+*?
www.whitenosesyndrome.orgFsitesFdefaultFfilesFresourceFnationalRwnsRreviseRfinalR;.*,.+*.#df ).
With the ever increasing manifestations of infected hibernacula! artificial roosting
locations would be most advantageous for bats fighting for survival in WNS regions. 0
recommend individuals #ost bat houses if a##licable. / bat house #rovides a sustainable and
clean location for bats to roost and live. 0nformation on #osting bat houses can be found at
3at$on.Erg (Tuttle! iser B iser! *+5? www.batcon.orgF#dfsF3>3uilders>dbk+5REnline.#df ). 0n
addition to smaller bat houses! abandoned buildings or barns also work well as artificial roosts
and if ones situations allows! the #resence of bats in such outbuildings should be welcomed. 3at
houses have recently come to the cam#us of Southern $onnecticut State =niversity in New
>aven! $T to #romote long-term research and most im#ortantly aid bat conservation in one of
the first states where WNS was discovered. 0ts recognied these local conservation efforts are
small com#ared to the large scale nature of WNS! but if doens of individuals were to become
involved across multi#le states the likelihood of #ersistence by some bat colonies would
increase.
S$S= 3iology
http://www.whitenosesyndrome.org/sites/default/files/resource/national_wns_revise_final_6.25.12.pdfhttp://www.batcon.org/pdfs/BHBuildersHdbk13_Online.pdfhttp://www.whitenosesyndrome.org/sites/default/files/resource/national_wns_revise_final_6.25.12.pdfhttp://www.batcon.org/pdfs/BHBuildersHdbk13_Online.pdf
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 26
1ossibly the biggest ste# individuals can take in the fight against WNS is to educate
others and hel# increase awareness. 0ts vital for everyone who reads this review to go out of
their way to discuss WNS with someone who was #reviously unaware. Think of the resources
and assistance which could come to fruition if more members of the general #ublic knew of
WNS and the forecasted outcomes of the disease.
*n c$osin%
WNS is a vile disease. /s 0ve discussed the #ast! #resent and future of WNS in bats its
easy to see how troublesome WNS is on so many fronts? yet! some ho#e has been seen in recent
#ublications which as#ire to answer the "uestion thats #lagued researchers from the start! the
"uestion of wondering how to fi% this calamity. The scientific community is so far from wherewe were in *;! our knowledge of WNS has increased e%#onentially! but many unanswered
"uestions remain and much work is left to be done. This review has covered works from nine
years of WNS research and brought together many testable hy#otheses. 0 ho#e this com#ilation
brings a new view#oint to data which may have been #reviously overlooked and u#on
reinvestigation! could now lead to new research! conservation and s#ecies management
o##ortunities. The #ursuance of scientific work throughout the remainder of this decade could
very well #rovide us with an answer of how to remedy WNS! bring our bats back from the brink
of e%tinction! and #reserve our natural history. $ertainly! the scientific community embraces the
challenge and looks forward to the o##ortunity.
Ac!no$ed%ements
Aany thanks to those who have hel#ed su##ort this research throughout all of its #hases. Your assistances
and enthusiasms are dee#ly a##reciated.
Lr. Airanda Lunbar
3iology Le#artment! Southern $onnecticut State =niversity Student @overnment /ssociation! Southern $onnecticut State =niversity
Lavid B Susan Wisniewski
S$S= 3iology
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The 1ast! 1resent and 2uture of White-Nose Syndrome in 3ats 27
eferences
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