White-nose Syndrome Research Articles

DNA metabarcoding analyses reveal fine-scale microbiome structures on Western Canadian bat wings.

Microbiomes play important roles in host health. White-nose syndrome (WNS), a fungal infection of bat wings and muzzles, has threatened bat populations across North America since 2006. Recent research suggest that the skin microbiome of bats may play a significant role in bat's susceptibility to WNS. However, relatively little is known about the skin microbiome composition and function in bats in Western Canada, a region with a high diversity of bats, but WNS has yet to be a major issue. Here, we revealed high bacterial and fungal diversities on the skin of three common bat species in Lillooet, British Columbia, including several highly prevalent microbial species that have been rarely reported in other regions. Our analyses showed fine-scale structures of bat wing microbiome based on local sites and bat species. The knowledge obtained from WNS-naïve bat populations in this study may help develop mitigation and management strategies against WNS.

Winter torpor patterns of tricolored bats (Perimyotis subflavus) in the southeastern United States

Abstract The Tricolored Bat (Perimyotis subflavus) has suffered significant population declines in much of its geographic range due to white-nose syndrome (WNS). Our aim was to describe the torpor patterns of tricolored bats within the southeastern United States to further our understanding of their winter ecology and potential susceptibility to WNS in currently unimpacted areas based on data from bats in both a WNS-affected hibernaculum and an unaffected hibernaculum. We placed temperature-sensitive radio transmitters on tricolored bats in a site in northwestern South Carolina that was WNS-positive and another site in northwestern Florida that was WNS-negative, and determined torpid and arousal skin temperatures (TSK), torpor bout duration (TBD), and arousal duration (AD) during 3 winters. Mean hibernacula temperature (TH) and vapor pressure deficit (VPDH) in both hibernacula were within the range of optimal Pseudogymnoascus destructans (Pd) growth (TH = 12.7 to 13.6 °C, VPDH = 0.028 to 0.059 kPA). Mean torpid TSK was 15.7 ± 0.1 °C and mean TBD was 4.1 ± 0.2 days across sites. Sex was the best predictor of TBD with males having significantly longer TBD than females. Torpid TSK was positively related to TH and negatively related to VPDH. Because the TSK of a bat was similar to the optimal growth temperatures of Pd, our findings suggest that even though winters in the southeastern United States are more benign than in other parts of the Tricolored Bat range, the warmer temperatures in southern hibernacula may provide optimal conditions for the growth of Pd. Greater understanding of the physiological responses of tricolored bats in hibernacula across their range will provide important data on the potential for WNS morbidity and mortality in unaffected areas and allow for a better distribution of resources for prevention and treatment of WNS.

Characterization of a High-Affinity Copper Transporter CTR1a in the White-Nose Syndrome Causing Fungal Pathogen Pseudogymnoascus destructans.

Copper is an essential micronutrient and the ability to scavenge tightly bound or trace levels of copper ions at the host-pathogen interface is vital for fungal proliferation in animal hosts. Recent studies suggest that trace metal ion acquisition is critical for the establishment and propagation of Pseudogymnoascus destructans, the fungal pathogen responsible for white-nose syndrome (WNS), on their bat host. However, little is known about these metal acquisition pathways in P. destructans. In this study, we report the characterization of the P. destructans high-affinity copper transporter VC83_00191 (PdCTR1a), which is implicated as a virulence factor associated with the WNS disease state. Using Saccharomyces cerevisiae as a recombinant expression host, we find that PdCTR1a can efficiently traffic Cu ions into the yeast cytoplasm. Complementary studies in the native P. destructans fungus provide evidence that PdCTR1a transcripts and protein levels are dictated by Cu-bioavailability in the growth media. Our study demonstrates that PdCTR1a is a functional high-affinity copper transporter and is relevant to Cu homeostasis pathways in P. destructans.

Vulnerability of Southern Hemisphere bats to white-nose syndrome based on global analysis of fungal host specificity and cave temperatures.

White-nose syndrome (WNS), a disease affecting hibernating bats, is caused by the fungal pathogen Pseudogymnoascus destructans (Pd). Since the initial introduction of Pd from Eurasia to the United States in 2006, WNS has killed millions of bats throughout the temperate parts of North America. There is concern that if Pd is accidentally introduced to the Southern Hemisphere, WNS could pose similar threats to the bat fauna of the Southern Hemisphere's more temperate regions. Efforts are required to better understand the vulnerability of bats globally to WNS. We examined phylogenetic distances among cave roosting bat species globally to estimate the probability of infection by Pd. We predicted cave thermal suitability for Pd for 441 cave-roosting bat species across the globe via spatial analysis. We used host specificity models based on 65 species tested for Pd to determine phylogenetic specificity of Pd. Phylogenetic distance was not an important predictor of Pd infection, confirming that Pd has low host specificity. We found extensive areas (i.e., South America, Africa, and Australia) in the Southern Hemisphere with caves that were suitable for cave-roosting bat species and for Pd growth. Hence, if Pd spreads to the Southern Hemisphere, the risk of exposure is widespread for cave-roosting bats, and infection is possible regardless of relatedness to infected species in the Northern Hemisphere. Predicting the consequences of infection remains difficult due to lack of species-specific information about bat winter biology. Nevertheless, WNS is an important threat to naive Southern Hemisphere bat populations. Hence, biosecurity measures and planning of management responses that can help prevent or minimize a potential WNS outbreak in the Southern Hemisphere are urgently needed.

Pseudogymnoascus destructans invasion stage impacts the skin microbial functions of highly vulnerable Myotis lucifugus.

The role of the skin microbiome in resistance and susceptibility of wildlife to fungal pathogens has been examined from a taxonomic perspective but skin microbial function, in the context of fungal infection, has yet to be studied. Our objective was to understand effects of a bat fungal pathogen site infection status and course of invasion on skin microbial function. We sampled seven hibernating colonies of Myotis lucifugus covering three-time points over the course of Pseudogymnoascus destructans (Pd) invasion and white nose syndrome (pre-invasion, epidemic and established). Our results support three new hypotheses about Pd and skin functional microbiome: 1) there is an important effect of Pd invasion stage, especially at the epidemic stage; 2) disruption by the fungus at the epidemic stage could decrease anti-fungal functions with potential negative effects on the microbiome and bat health; 3) the collection site might have a larger influence on microbiomes at the pre-invasion stage rather than at epidemic and established stages. Future studies with larger samples size and using meta-omics approaches will help confirm these hypotheses, and determine the influence of the microbiome on wildlife survival to fungal disease.

Tricolored Bat (Perimyotis subflavus) microsite use throughout hibernation

Abstract White-nose syndrome (WNS) has caused dramatic population declines in several bat species, including the Tricolored Bat (Perimyotis subflavus). Several studies have documented bats using colder roosting temperatures after infection; however, this strategy may have costs such as increased freezing risks or greater predation risks and it is unknown when during hibernation bats begin to utilize these colder temperatures. Our aim was to examine Tricolored Bat roost locations in a WNS-positive site in relation to roost microclimate and other environmental conditions throughout the hibernation season. We conducted monthly censuses of tricolored bats across 2 hibernation seasons (November to March 2020 to 2021 and October to March 2021 to 2022) in a WNS-positive hibernaculum in northwestern South Carolina and recorded skin and adjacent wall temperature, tunnel section, and distance from the entrance for each bat species. We continuously measured hibernacula temperature and relative humidity during both hibernation seasons. Most bats roosted in the back part of the tunnel where temperatures were warmer and more stable, and vapor pressure deficit (VPD) and human disturbance were low. However, >20% of bats roosted in the front, where roost temperatures were significantly colder and VPD was higher but more variable; human disturbance was also higher in this section. The proportion of bats in each tunnel section did not vary among months and we did not find evidence of significant movement to the front section of the tunnel as hibernation progressed based on marked bats; however, bats in the front section roosted higher on the wall suggesting that they may be avoiding human disturbance or predators. Our results support the notion that no optimum hibernation temperature exists for tricolored bats and that high VPD and disturbance are likely important factors driving microsite use. Protection of Tricolored Bat hibernacula that offer a range of microclimates or a network of sites in close proximity that offer different microclimates may be helpful for recovery of this species.

Maximizing benefits to bat populations through management of power line corridors

Abstract Power line corridors are ubiquitous worldwide and are commonly used by bats as habitat. Targeted management of these corridor habitats has the potential to aid bat populations, which is critically important given the multifaceted threats facing bat species, including the emerging infectious disease white‐nose syndrome (WNS) in North America. Here, we review known and potential impacts of management of existing power line corridors on three bat behaviours: foraging, roosting and commuting. We also identify bats in the United States that would benefit from changes to management of power line corridors for improvements to roosting and foraging habitats, particularly species of conservation concern that roost and forage along forest edges. Key recommendations are to avoid disturbance to roosting bats when maintaining vegetation along power line corridors, apply integrated vegetation management to maximize native plant diversity to improve prey options for bats and apply targeted interventions (e.g. artificial roost creation, creation of ponds) in a well‐justified ecological context. Practical implication. We highlight high‐priority research topics to fill knowledge gaps, including testing whether vegetation management treatments targeting plant and insect communities increase bat fitness and cause positive population‐level responses in focal bat species. We conclude that building evidence on how bats are affected by power line corridor management is a conservation need.

Dynamic occupancy in a peripheral population of Myotis septentrionalis during disease outbreak

ContextOnce common, the northern long-eared bat (Myotis septentrionalis) has experienced declines > 90% due to white-nose syndrome (WNS). This severe mortality has resulted in their listing under the Endangered Species Act and made them a conservation priority. However, their broad distribution, variability in habitat use, and population instability make developing range-wide conservation strategies difficult. To understand how conservation of M. septentrionalis may vary across its range, we examined shifts in M. septentrionalis site occupancy on the edge of their historic range following severe WNS mortality.ObjectivesOur goal was to determine how mortality from white-nose syndrome affects site occupancy of M. septentrionalis at the southern edge of their historic range. Understanding which areas will remain occupied during disease related mortality will help inform management during disease outbreaks.MethodsWe used 11 years (2007–2017) of mist-netting records to construct dynamic occupancy models of M. septentrionalis in northern Georgia, USA. Occupancy was updated annually, with the initial period defined as all years prior to the winter of 2012–2013, which corresponds to when white-nose syndrome entered the study area. We assessed occupancy using landscape metrics at the home range (65 ha) and landscape (491 ha) scales, year since WNS occurrence in the study area, distance to karst, and distance to nearest WNS positive county. We estimated probability of detection using Julian date and sampling effort.ResultsInitial site occupancy was positively associated with percent deciduous forest cover at the home range scale. As M. septentrionalis populations declined from WNS, a site becoming unoccupied was negatively correlated with mean contiguity of forest at the home range scale and largest patch of forest and mean elevation at the landscape scale. Site occupancy declined precipitously in the years following WNS, dropping from 70.75% (41.76–96.98% [95% CI]) occupancy pre-WNS to 0.3% (0.3–20.5% [95% CI]) by the final year of the study.ConclusionsOur results demonstrated that sites occupied by M. septentrionalis closer to the historic range edge were more vulnerable to becoming unoccupied after disease arrival. We recommend managers on the periphery of the historic range focus conservation efforts on high elevation forested areas nearer to the range core.

Signals of positive selection in genomes of palearctic Myotis-bats coexisting with a fungal pathogen

Disease can act as a driving force in shaping genetic makeup across populations, even species, if the impacts influence a particularly sensitive part of their life cycles. White-nose disease is caused by a fungal pathogen infecting bats during hibernation. The mycosis has caused massive population declines of susceptible species in North America, particularly in the genus Myotis. However, Myotis bats appear to tolerate infection in Eurasia, where the fungal pathogen has co-evolved with its bat hosts for an extended period of time. Therefore, with susceptible and tolerant populations, the fungal disease provides a unique opportunity to tease apart factors contributing to tolerance at a genomic level to and gain an understanding of the evolution of non-harmful in host-parasite interactions. To investigate if the fungal disease has caused adaptation on a genomic level in Eurasian bat species, we adopted both whole-genome sequencing approaches and a literature search to compile a set of 300 genes from which to investigate signals of positive selection in genomes of 11 Eurasian bats at the codon-level. Our results indicate significant positive selection in 38 genes, many of which have a marked role in responses to infection. Our findings suggest that white-nose syndrome may have applied a significant selective pressure on Eurasian Myotis-bats in the past, which can contribute their survival in co-existence with the pathogen. Our findings provide an insight on the selective pressure pathogens afflict on their hosts using methodology that can be adapted to other host-pathogen study systems.

Impact of putatively beneficial genomic loci on gene expression in little brown bats (Myotis lucifugus, Le Conte, 1831) affected by white-nose syndrome.

Genome-wide scans for selection have become a popular tool for investigating evolutionary responses in wildlife to emerging diseases. However, genome scans are susceptible to false positives and do little to demonstrate specific mechanisms by which loci impact survival. Linking putatively resistant genotypes to observable phenotypes increases confidence in genome scan results and provides evidence of survival mechanisms that can guide conservation and management efforts. Here we used an expression quantitative trait loci (eQTL) analysis to uncover relationships between gene expression and alleles associated with the survival of little brown bats (Myotis lucifugus) despite infection with the causative agent of white-nose syndrome. We found that 25 of the 63 single-nucleotide polymorphisms (SNPs) associated with survival were related to gene expression in wing tissue. The differentially expressed genes have functional annotations associated with the innate immune system, metabolism, circadian rhythms, and the cellular response to stress. In addition, we observed differential expression of multiple genes with survival implications related to loci in linkage disequilibrium with focal SNPs. Together, these findings support the selective function of these loci and suggest that part of the mechanism driving survival may be the alteration of immune and other responses in epithelial tissue.

Characterization of a High-Affinity Copper Transporter in the White-Nose Syndrome Causing Fungal Pathogen Pseudogymnoascus destructans.

Copper is an essential micronutrient and the ability to scavenge tightly bound or trace levels of copper ions at the host-pathogen interface is vital for fungal proliferation in animal hosts. Recent studies suggest that trace metal ion acquisition is critical for the establishment and propagation of Pseudogymnoascus destructans, the fungal pathogen responsible for white-nose syndrome (WNS), on their bat host. However, little is known about these metal acquisition pathways in P. destructans. In this study, we report the characterization of the P. destructans high-affinity copper transporter VC83_00191 (PdCTR1a), which is implicated as a virulence factor associated with the WNS disease state. Using Saccharomyces cerevisiae as a recombinant expression host, we find that PdCTR1a localizes to the cell surface plasma membrane and can efficiently traffic Cu-ions into the yeast cytoplasm. Complementary studies in the native P. destructans fungus provide evidence that PdCTR1a transcripts and protein levels are dictated by Cu-bioavailability in the growth media. Our study demonstrates that PdCTR1a is a functional high-affinity copper transporter and is relevant to Cu-homeostasis pathways in P. destructans.

White adipose tissue remodeling in Little Brown Myotis (Myotis lucifugus) with white-nose syndrome.

White-nose syndrome (WNS) is a fungal wildlife disease of bats that has caused precipitous declines in certain Nearctic bat species. A key driver of mortality is premature exhaustion of fat reserves, primarily white adipose tissue (WAT), that bats rely on to meet their metabolic needs during winter. However, the pathophysiological and metabolic effects of WNS have remained ill-defined. To elucidate metabolic mechanisms associated with WNS mortality, we infected a WNS susceptible species, the Little Brown Myotis (Myotis lucifugus), with Pseudogymnoascus destructans (Pd) and collected WAT biopsies for histology and targeted lipidomics. These results were compared to the WNS-resistant Big Brown Bat (Eptesicus fuscus). A similar distribution in broad lipid class was observed in both species, with total WAT primarily consisting of triacylglycerides. Baseline differences in WAT chemical composition between species showed that higher glycerophospholipids (GPs) levels in E. fuscus were dominated by unsaturated or monounsaturated moieties and n-6 (18:2, 20:2, 20:3, 20:4) fatty acids. Conversely, higher GP levels in M. lucifugus WAT were primarily compounds containing n-3 (20:5 and 22:5) fatty acids. Following Pd-infection, we found that perturbation to WAT reserves occurs in M. lucifugus, but not in the resistant E. fuscus. A total of 66 GPs (primarily glycerophosphocholines and glycerophosphoethanolamines) were higher in Pd-infected M. lucifugus, indicating perturbation to the WAT structural component. In addition to changes in lipid chemistry, smaller adipocyte sizes and increased extracellular matrix deposition was observed in Pd-infected M. lucifugus. This is the first study to describe WAT GP composition of bats with different susceptibilities to WNS and highlights that recovery from WNS may require repair from adipose remodeling in addition to replenishing depot fat during spring emergence.

Microbiota diversity and anti-Pseudogymnoascus destructans bacteria isolated from Myotis pilosus skin during late hibernation.

Symbiotic microorganisms that reside on the host skin serve as the primary defense against pathogens in vertebrates. Specifically, the skin microbiome of bats may play a crucial role in providing resistance against Pseudogymnoascus destructans (Pd), the pathogen causing white-nose syndrome. However, the epidermis symbiotic microbiome and its specific role in resisting Pd in highly resistant bats in Asia are still not well understood. In this study, we collected and characterized skin microbiota samples of 19 Myotis pilosus in China and explored the differences between Pd-positive and negative individuals. We identified inhibitory effects of these bacteria through cultivation methods. Our results revealed that the Simpson diversity index of the skin microbiota for positive individuals was significantly lower than that of negative individuals, and the relative abundance of Pseudomonas was significantly higher in positive bats. Regardless of whether individuals were positive or negative for Pd, the relative abundance of potentially antifungal genera in skin microbiota was high. Moreover, we successfully isolated 165 microbes from bat skin and 41 isolates from positive individuals able to inhibit Pd growth compared to only 12 isolates from negative individuals. A total of 10 genera of Pd-inhibiting bacteria were screened, among which the genera Algoriella, Glutamicibacter, and Psychrobacter were newly discovered as Pd-inhibiting genera. These Pd-inhibiting bacteria metabolized a variety of volatile compounds, including dimethyl trisulfide, dimethyl disulfide, propylene sulfide, 2-undecanone, and 2-nonanone, which were able to completely inhibit Pd growth at low concentrations.IMPORTANCERecently, white-nose syndrome has caused the deaths of millions of hibernating bats, even threatening some with regional extinction. Bats in China with high resistance to Pseudogymnoascus destructans can provide a powerful reference for studying the management of white-nose syndrome and understanding the bats against the pathogen's intrinsic mechanisms. This study sheds light on the crucial role of host symbiotic skin microorganisms in resistance to pathogenic fungi and highlights the potential for harnessing natural defense mechanisms for the prevention and treatment of white-nose syndrome. In addition, this may also provide promising candidates for the development of bioinsecticides and fungicides that offer new avenues for addressing fungal diseases in wildlife and agricultural environments.

The skin I live in: Pathogenesis of white-nose syndrome of bats.

The emergence of white-nose syndrome (WNS) in North America has resulted in mass mortalities of hibernating bats and total extirpation of local populations. The need to mitigate this disease has stirred a significant body of research to understand its pathogenesis. Pseudogymnoascus destructans, the causative agent of WNS, is a psychrophilic (cold-loving) fungus that resides within the class Leotiomycetes, which contains mainly plant pathogens and is unrelated to other consequential pathogens of animals. In this review, we revisit the unique biology of hibernating bats and P. destructans and provide an updated analysis of the stages and mechanisms of WNS progression. The extreme life history of hibernating bats, the psychrophilic nature of P. destructans, and its evolutionary distance from other well-characterized animal-infecting fungi translate into unique host-pathogen interactions, many of them yet to be discovered.

Pathogenic strategies of Pseudogymnoascus destructans during torpor and arousal of hibernating bats.

Millions of hibernating bats across North America have died from white-nose syndrome (WNS), an emerging disease caused by a psychrophilic (cold-loving) fungus, Pseudogymnoascus destructans, that invades their skin. Mechanisms of P. destructans invasion of bat epidermis remain obscure. Guided by our in vivo observations, we modeled hibernation with a newly generated little brown bat (Myotis lucifugus) keratinocyte cell line. We uncovered the stealth intracellular lifestyle of P. destructans, which inhibits apoptosis of keratinocytes and spreads through the cells by two epidermal growth factor receptor (EGFR)-dependent mechanisms: active penetration during torpor and induced endocytosis during arousal. Melanin of endocytosed P. destructans blocks endolysosomal maturation, facilitating P. destructans survival and germination after return to torpor. Blockade of EGFR aborts P. destructans entry into keratinocytes.

Drivers of population dynamics of at-risk populations change with pathogen arrival

Successful wildlife conservation in an era of global change requires understanding determinants of species population growth. However, when populations are faced with novel stressors, factors associated with healthy populations can change, necessitating shifting conservation strategies. For example, emerging infectious diseases can cause conditions previously beneficial to host populations to increase disease impacts. Here, we paired a population dataset of 265 colonies of the federally endangered Indiana bat (Myotis sodalis) with 50.7 logger-years of environmental data to explore factors that affected colony response to white-nose syndrome (WNS), an emerging fungal disease. We found variation in colony responses to WNS, ranging from extirpation to stabilization. The severity of WNS impacts was associated with hibernaculum temperature, as colonies of cold hibernacula declined more severely than those in relatively warm hibernacula, an association that arose following pathogen emergence. Interestingly, this association was opposite that of a sympatric bat species, the little brown bat (Myotis lucifugus), illustrating that environmental dependence of disease can vary by species in a multi-host community. Simulating future colony dynamics suggests that most extirpations have already occurred, as the pathogen has been present for several years in most colonies, and that relatively small colonies are more susceptible to extirpation. Overall, this study illustrates that emerging infectious diseases can change the factors associated with host population growth, including through novel environmental associations that vary by host species. Consideration of these shifting associations and differences between impacted species will be essential to the conservation of host communities challenged by emerging infectious disease.

Cave Biodiversity of Cumberland Gap National Historical Park

Recognized as an important pathway between the east coast and the interior of the United States, much of the Cumberland Gap has been protected as part of the Cumberland Gap National Historical Park (CUGA). CUGA also contains extensive karst habitats, including Gap Cave, one of the longest caves in Virginia. With the aim of better understanding the cave biodiversity of CUGA, we conducted biological surveys in park caves and compiled records of other animals from CUGA caves, including bat monitoring data extending back more than 35 years. Results of that work include: (1) collecting five new cave-obligate species (troglobionts) from CUGA caves, increasing the number of troglobionts known from CUGA from 11 to 16; (2) increasing the total records of troglobionts in CUGA caves from 17 to 39; (3) finding an undescribed isopod (now described as Lirceus zigleri) in the Gap Cave stream; (4) noting six species of bats, including two federally endangered species—Indiana bats (Myotis sodalis) and northern long-eared bats (Myotis septentrionalis)—from CUGA caves; and (5) recognizing that Gap Cave once hosted one of the largest known populations of Indiana bats in Virginia. We present an annotated list of the animals found in the caves of the park. The caves of the Cumberland Gap National Historical Park provide critical habitat to two groups of species with distinct conservation concerns: poorly known troglobionts that exhibit extreme endemicity and bats under threat from white-nose syndrome disease.

Summer cave use by tricolored bats declined in response to white-nose syndrome despite persistence in winter hibernacula in the southeastern United States

Summer cave use by tricolored bats declined in response to white-nose syndrome despite persistence in winter hibernacula in the southeastern United States

Heterogenous effects of bat declines from white‐nose syndrome on arthropods

AbstractIn North America, white‐nose syndrome (WNS) has caused precipitous declines in hibernating bat populations, raising the question of whether the rapid loss of arthropodivorous bats may affect the abundance of their prey. During the summers of 2015–2018 (1 year after the arrival of WNS in Wisconsin, USA), we performed intensive arthropod black‐light trapping, ultrasonic acoustic monitoring, and emergence counts at 10 little brown (Myotis lucifugus) and big brown (Eptesicus fuscus) bat maternity roosts with paired control sites. For little brown bats, which are severely affected by WNS, roost counts declined by 95% over the four‐year period, compared to a 38% decline in big brown bat roost counts. Total arthropod abundance decreased by 49%, although decreases among common little brown bat prey were less severe. Our natural predator exclusion experiment supports existing evidence that bats can have measurable trophic impacts on arthropod communities, primarily via top‐down effects on common prey.

Disentangling genetic diversity of Myotis septentrionalis: population structure, demographic history, and effective population size

Abstract Myotis septentrionalis (Northern Long-eared Bat) has recently suffered a >90% decline in population size in North America due to white-nose syndrome (WNS). We assessed genetic diversity, population structure, current effective population size, and demographic history of M. septentrionalis distributed across the United States to determine baseline levels pre-WNS. We analyzed RADseq data from 81 individuals from Kentucky, Louisiana, Michigan, Minnesota, North Carolina, Oklahoma, and Wisconsin. Additionally, we examined population genetic structure using discriminant analysis of principal components, fastStructure, and STRUCTURE. We then estimated effective population size and demographic history using fastsimcoal2. Similar levels of genetic diversity were found across all samples. We found no population genetic structure in the varied analyses from these contemporary samples. The best model for demographic history estimated a rapid population expansion followed by a slower expansion approximately 340,000 years ago. The vagility of M. septentrionalis, along with male dispersal and random mating, may provide a buffer against serious bottleneck effects stemming from rapid population declines due to WNS. This research provides a baseline for tracking and monitoring the influence of WNS on genetic diversity such as potential reduced diversity or increased population structuring in the future.