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Whiting-Fawcett F, Blomberg AS, Troitsky T, Meierhofer MB, Field KA, Puechmaille SJ, Lilley TM. A Palearctic view of a bat fungal disease. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2024:e14265. [PMID: 38616727 DOI: 10.1111/cobi.14265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 01/02/2024] [Accepted: 01/20/2024] [Indexed: 04/16/2024]
Abstract
The fungal infection causing white-nose disease in hibernating bats in North America has resulted in dramatic population declines of affected species, since the introduction of the causative agent Pseudogymnoascus destructans. The fungus is native to the Palearctic, where it also infects several bat species, yet rarely causes severe pathology or the death of the host. Pseudogymnoascus destructans infects bats during hibernation by invading and digesting the skin tissue, resulting in the disruption of torpor patterns and consequent emaciation. Relations among pathogen, host, and environment are complex, and individuals, populations, and species respond to the fungal pathogen in different ways. For example, the Nearctic Myotis lucifugus responds to infection by mounting a robust immune response, leading to immunopathology often contributing to mortality. In contrast, the Palearctic M. myotis shows no significant immunological response to infection. This lack of a strong response, resulting from the long coevolution between the hosts and the pathogen in the pathogen's native range, likely contributes to survival in tolerant species. After more than 15 years since the initial introduction of the fungus to North America, some of the affected populations are showing signs of recovery, suggesting that the fungus, hosts, or both are undergoing processes that may eventually lead to coexistence. The suggested or implemented management methods of the disease in North America have encompassed, for example, the use of probiotics and fungicides, vaccinations, and modifying the environmental conditions of the hibernation sites to limit the growth of the pathogen, intensity of infection, or the hosts' responses to it. Based on current knowledge from Eurasia, policy makers and conservation managers should refrain from disrupting the ongoing evolutionary processes and adopt a holistic approach to managing the epizootic.
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Affiliation(s)
- F Whiting-Fawcett
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, UK
- BatLab Finland, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - A S Blomberg
- BatLab Finland, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - T Troitsky
- BatLab Finland, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - M B Meierhofer
- BatLab Finland, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - K A Field
- Department of Biology, Bucknell University, Lewisburg, Pennsylvania, USA
| | - S J Puechmaille
- Institut des Sciences de l'Évolution Montpellier (ISEM), University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
- Institut Universitaire de France, Paris, France
| | - T M Lilley
- BatLab Finland, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
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Ange-Stark M, Parise KL, Cheng TL, Hoyt JR, Langwig KE, Frick WF, Kilpatrick AM, Gillece J, MacManes MD, Foster JT. White-nose syndrome restructures bat skin microbiomes. Microbiol Spectr 2023; 11:e0271523. [PMID: 37888992 PMCID: PMC10714735 DOI: 10.1128/spectrum.02715-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/13/2023] [Indexed: 10/28/2023] Open
Abstract
IMPORTANCE Inherent complexities in the composition of microbiomes can often preclude investigations of microbe-associated diseases. Instead of single organisms being associated with disease, community characteristics may be more relevant. Longitudinal microbiome studies of the same individual bats as pathogens arrive and infect a population are the ideal experiment but remain logistically challenging; therefore, investigations like our approach that are able to correlate invasive pathogens to alterations within a microbiome may be the next best alternative. The results of this study potentially suggest that microbiome-host interactions may determine the likelihood of infection. However, the contrasting relationship between Pd and the bacterial microbiomes of Myotis lucifugus and Perimyotis subflavus indicate that we are just beginning to understand how the bat microbiome interacts with a fungal invader such as Pd.
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Affiliation(s)
- Meghan Ange-Stark
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Katy L. Parise
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Tina L. Cheng
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA
- Bat Conservation International, Austin, Texas, USA
| | - Joseph R. Hoyt
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Kate E. Langwig
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Winifred F. Frick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA
- Bat Conservation International, Austin, Texas, USA
| | - A. Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA
| | - John Gillece
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Matthew D. MacManes
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Jeffrey T. Foster
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
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Moran ML, Boyd W, De La Cruz JL, Bertke AS, Ford WM. Oral Sampling of Little Brown Bat (Myotis lucifugus) Maternity Colonies for SARS-CoV-2 in the Northeast and Mid-Atlantic, USA. Animals (Basel) 2023; 13:550. [PMID: 36830336 PMCID: PMC9951713 DOI: 10.3390/ani13040550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
The potential introduction of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, into North American bat populations is of interest to wildlife managers due to recent disease-mediated declines of several species. Populations of little brown bats (Myotis lucifugus) have collapsed due to white-nose syndrome (WNS), a disease caused by the introduction and spread of the fungal pathogen Pseudogymnoascus destructans (Pd). Throughout much of the United States and southern Canada, large colonies of the species routinely established diurnal roosts in anthropogenic structures, thereby creating the potential for direct human contact and cross-species disease transmission. Given recent declines and the potential for further disease impacts, we collected oral swabs from eight little brown bat maternity colonies to assess the presence and prevalence of SARS-CoV-2 by RT-qPCR analysis. Little brown bat colonies in Maryland (n = 1), New Hampshire (n = 1), New Jersey (n = 2), New York (n = 1), Rhode Island (n = 2), and Virginia (n = 1) were taken during May-August, 2022. From 235 assayed individuals, no bat tested positive for SARS-CoV-2. Our results indicate that little brown bats may not contract SARS-CoV-2 or that the virus persists at undetectable levels in populations of the Mid-Atlantic and Northeast during summer months. Nonetheless, continued monitoring and future work addressing other seasons may still be warranted to conclusively determine infection status.
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Affiliation(s)
- Megan L. Moran
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - William Boyd
- Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Jesse L. De La Cruz
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Andrea S. Bertke
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center for Emerging Zoonotic and Arthropod-Borne Pathogens, Blacksburg, VA 24061, USA
| | - W. Mark Ford
- U.S. Geological Survey, Virginia Cooperative Fish and Wildlife Research Unit, Blacksburg, VA 24061, USA
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Grimaudo AT, Hoyt JR, Yamada SA, Herzog CJ, Bennett AB, Langwig KE. Host traits and environment interact to determine persistence of bat populations impacted by white-nose syndrome. Ecol Lett 2022; 25:483-497. [PMID: 34935272 PMCID: PMC9299823 DOI: 10.1111/ele.13942] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/26/2021] [Accepted: 11/17/2021] [Indexed: 11/27/2022]
Abstract
Emerging infectious diseases have resulted in severe population declines across diverse taxa. In some instances, despite attributes associated with high extinction risk, disease emergence and host declines are followed by host stabilisation for unknown reasons. While host, pathogen, and the environment are recognised as important factors that interact to determine host-pathogen coexistence, they are often considered independently. Here, we use a translocation experiment to disentangle the role of host traits and environmental conditions in driving the persistence of remnant bat populations a decade after they declined 70-99% due to white-nose syndrome and subsequently stabilised. While survival was significantly higher than during the initial epidemic within all sites, protection from severe disease only existed within a narrow environmental space, suggesting host traits conducive to surviving disease are highly environmentally dependent. Ultimately, population persistence following pathogen invasion is the product of host-pathogen interactions that vary across a patchwork of environments.
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Affiliation(s)
| | - Joseph R. Hoyt
- Department of Biological SciencesVirginia TechBlacksburgVirginiaUSA
| | | | - Carl J. Herzog
- New York State Department of Environmental ConservationAlbanyNew YorkUSA
| | | | - Kate E. Langwig
- Department of Biological SciencesVirginia TechBlacksburgVirginiaUSA
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Summer Populations of Northern Long-eared Bat in an Eastern Kentucky Forest Following Arrival of White-nose Syndrome. AMERICAN MIDLAND NATURALIST 2022. [DOI: 10.1674/0003-0031-187.1.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Vanderwolf KJ, Campbell LJ, Goldberg TL, Blehert DS, Lorch JM. Skin fungal assemblages of bats vary based on susceptibility to white-nose syndrome. THE ISME JOURNAL 2021; 15:909-920. [PMID: 33149209 PMCID: PMC8027032 DOI: 10.1038/s41396-020-00821-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/15/2020] [Accepted: 10/22/2020] [Indexed: 01/30/2023]
Abstract
Microbial skin assemblages, including fungal communities, can influence host resistance to infectious diseases. The diversity-invasibility hypothesis predicts that high-diversity communities are less easily invaded than species-poor communities, and thus diverse microbial communities may prevent pathogens from colonizing a host. To explore the hypothesis that host fungal communities mediate resistance to infection by fungal pathogens, we investigated characteristics of bat skin fungal communities as they relate to susceptibility to the emerging disease white-nose syndrome (WNS). Using a culture-based approach, we compared skin fungal assemblage characteristics of 10 bat species that differ in susceptibility to WNS across 10 eastern U.S. states. The fungal assemblages on WNS-susceptible bat species had significantly lower alpha diversity and abundance compared to WNS-resistant species. Overall fungal assemblage structure did not vary based on WNS-susceptibility, but several yeast species were differentially abundant on WNS-resistant bat species. One yeast species inhibited Pseudogymnoascus destructans (Pd), the causative agent on WNS, in vitro under certain conditions, suggesting a possible role in host protection. Further exploration of interactions between Pd and constituents of skin fungal assemblages may prove useful for predicting susceptibility of bat populations to WNS and for developing effective mitigation strategies.
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Affiliation(s)
- Karen J Vanderwolf
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WIS, USA
- U.S. Geological Survey, National Wildlife Health Center, Madison, WIS, USA
| | - Lewis J Campbell
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WIS, USA
- U.S. Geological Survey, National Wildlife Health Center, Madison, WIS, USA
| | - Tony L Goldberg
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WIS, USA
| | - David S Blehert
- U.S. Geological Survey, National Wildlife Health Center, Madison, WIS, USA
| | - Jeffrey M Lorch
- U.S. Geological Survey, National Wildlife Health Center, Madison, WIS, USA.
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Vanderwolf KJ, McAlpine DF. Hibernacula microclimate and declines in overwintering bats during an outbreak of white-nose syndrome near the northern range limit of infection in North America. Ecol Evol 2021; 11:2273-2288. [PMID: 33717454 PMCID: PMC7920769 DOI: 10.1002/ece3.7195] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/07/2020] [Accepted: 12/18/2020] [Indexed: 01/13/2023] Open
Abstract
We document white-nose syndrome (WNS), a lethal disease of bats caused by the fungus Pseudogymnoascus destructans (Pd), and hibernacula microclimate in New Brunswick, Canada. Our study area represents a more northern region than is common for hibernacula microclimate investigations, providing insight as to how WNS may impact bats at higher latitudes. To determine the impact of the March 2011 arrival of Pd in New Brunswick and the role of hibernacula microclimate on overwintering bat mortality, we surveyed bat numbers at hibernacula twice a year from 2009 to 2015. We also collected data from iButton temperature loggers deployed at all sites and data from HOBO temperature and humidity loggers at three sites. Bat species found in New Brunswick hibernacula include Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long-eared Bat), with small numbers of Perimyotis subflavus (Tricolored Bat). All known hibernacula in the province were Pd-positive with WNS-positive bats by winter 2013. A 99% decrease in the overwintering bat population in New Brunswick was observed between 2011 and 2015. We did not observe P. subflavus during surveys 2013-2015 and the species appears to be extirpated from these sites. Bats did not appear to choose hibernacula based on winter temperatures, but dark zone (zone where no light penetrates) winter temperatures did not differ among our study sites. Winter dark zone temperatures were warmer and less variable than entrance or above ground temperatures. We observed visible Pd growth on hibernating bats in New Brunswick during early winter surveys (November), even though hibernacula temperatures were colder than optimum for in vitro Pd growth. This suggests that cold hibernacula temperatures encountered near the apparent northern range limit for Pd do not sufficiently slow fungal growth to prevent the onset of WNS and associated bat mortality over the winter.
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Affiliation(s)
- Karen J. Vanderwolf
- Canadian Wildlife FederationKanataONCanada
- New Brunswick MuseumSaint JohnNBCanada
- Present address:
Trent UniversityPeterboroughONCanada
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Abstract
The recent introduction of Pseudogymnoascus destructans (the fungal pathogen that causes white-nose syndrome in bats) from Eurasia to North America has resulted in the collapse of North American bat populations and restructured species communities. The long evolutionary history between P. destructans and bats in Eurasia makes understanding host life history essential to uncovering the ecology of P. destructans. In this Review, we combine information on pathogen and host biology to understand the patterns of P. destructans spread, seasonal transmission ecology, the pathogenesis of white-nose syndrome and the cross-scale impact from individual hosts to ecosystems. Collectively, this research highlights how early pathogen detection and quantification of host impacts has accelerated the understanding of this newly emerging infectious disease.
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Fuller NW, McGuire LP, Pannkuk EL, Blute T, Haase CG, Mayberry HW, Risch TS, Willis CKR. Disease recovery in bats affected by white-nose syndrome. J Exp Biol 2020; 223:jeb211912. [PMID: 32054681 DOI: 10.1242/jeb.211912] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 02/10/2020] [Indexed: 12/28/2022]
Abstract
Processes associated with recovery of survivors are understudied components of wildlife infectious diseases. White-nose syndrome (WNS) in bats provides an opportunity to study recovery of disease survivors, understand implications of recovery for individual energetics, and assess the role of survivors in pathogen transmission. We documented temporal patterns of recovery from WNS in little brown bats (Myotis lucifugus) following hibernation to test the hypotheses that: (1) recovery of wing structure from WNS matches a rapid time scale (i.e. approximately 30 days) suggested by data from free-ranging bats; (2) torpor expression plays a role in recovery; (3) wing physiological function returns to normal alongside structural recovery; and (4) pathogen loads decline quickly during recovery. We collected naturally infected bats at the end of hibernation, brought them into captivity, and quantified recovery over 40 days by monitoring body mass, wing damage, thermoregulation, histopathology of wing biopsies, skin surface lipids and fungal load. Most metrics returned to normal within 30 days, although wing damage was still detectable at the end of the study. Torpor expression declined overall throughout the study, but bats expressed relatively shallow torpor bouts - with a plateau in minimum skin temperature - during intensive healing between approximately days 8 and 15. Pathogen loads were nearly undetectable after the first week of the study, but some bats were still detectably infected at day 40. Our results suggest that healing bats face a severe energetic imbalance during early recovery from direct costs of healing and reduced foraging efficiency. Management of WNS should not rely solely on actions during winter, but should also aim to support energy balance of recovering bats during spring and summer.
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Affiliation(s)
- Nathan W Fuller
- Department of Biological Sciences, Texas Tech University, 2901 Main Street, Lubbock, TX 79409, USA
| | - Liam P McGuire
- Department of Biological Sciences, Texas Tech University, 2901 Main Street, Lubbock, TX 79409, USA
| | - Evan L Pannkuk
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, 3970 Reservoir Road NW, Washington, DC 20057, USA
| | - Todd Blute
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Catherine G Haase
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Heather W Mayberry
- Department of Ecology and Evolutionary Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, Canada L5L 1C6
| | - Thomas S Risch
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 847, Jonesboro, AR 72467, USA
| | - Craig K R Willis
- Department of Biology and Centre for Forest Inter-Disciplinary Research (C-FIR), University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, Canada R3B 2E9
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Frank CL, Davis AD, Herzog C. The evolution of a bat population with white-nose syndrome (WNS) reveals a shift from an epizootic to an enzootic phase. Front Zool 2019; 16:40. [PMID: 31827569 PMCID: PMC6889174 DOI: 10.1186/s12983-019-0340-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/15/2019] [Indexed: 11/10/2022] Open
Abstract
Background White-nose Syndrome (WNS) is a mycosis caused by a cutaneous infection with the fungus Pseudogymnoascus destructans (Pd). It produces hibernation mortality rates of 75-98% in 4 bats: Myotis lucifugus, M. septentrionalis, M. sodalis, and Perimyotis subflavus. These high mortality rates were observed during the first several years after the arrival of P. destructans at a hibernation site. Mortality is caused by a 60% decrease in torpor bout duration, which results in a premature depletion of depot fat prior to spring. Results Little is known about the long-term effects of Pd on torpor and mortality, thus we conducted a 9-year study on M. lucifugus at 5 of the hibernation sites where Pd first appeared in North America during the winter of 2007-08. The M. lucifugus hibernating at one of these sites one year after the arrival of Pd (2008-09) had: a) a mean torpor bout duration of 7.6 d, b) no depot fat reserves by March, and c) an apparent over-winter mortality rate of 88%. The M. lucifugus hibernating at this same site 6-9 years after the arrival of Pd, in contrast, had: a) a mean torpor bout duration of 14.7 d, b) depot fat remaining in March, and c) an apparent mortality rate of 50%. The number of M. lucifugus hibernating at 2 of these sites has consistently increased since 2010 and is now more than 3.0-fold higher than the number remaining after the winter of 2008-09. Conclusions These findings indicate that this population of M. lucifugus has evolved mechanisms to hibernate well in the presence of Pd, thus reducing over-winter mortality.
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Affiliation(s)
- Craig L Frank
- 1Department of Biological Sciences, Fordham University, The Louis Calder Center, P.O. Box 887, Armonk, NY 10504 USA
| | - April D Davis
- 2Griffin Laboratory, Wadsworth Center, New York State Department of Health, 5668 State Farm Road, Slingerlands, NY 12159 USA
| | - Carl Herzog
- 3New York State Department of Environmental Conservation, 625 Broadway, Albany, NY 12233 USA
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Abstract
White-nose syndrome (WNS) affects bats primarily in winter, with Pseudogymnoascus destructans, the fungus that causes WNS, growing on bats in colder climates as they are hibernating. As a result, nearly all disease investigations have been conducted on bats in the winter or as they are emerging in spring. Although P. destructans has been detected on bats during the summer season, the seasonal dynamics of infection during this period remain poorly understood. To test for the presence of P. destructans during the summer season, we sampled bats that were free flying from June 2017 to September 2017 and also sampled bats from a maternity roost in August and outside a known hibernaculum in September. We collected skin swabs from the muzzle and forearm of bats, and using real-time PCR methods, we detected P. destructans DNA on 16% (12/76) of bats sampled in Wisconsin, US, including juvenile little brown bats (Myotis lucifugus) from bat house maternity roosts, and free-flying adult bats of two species captured in June, the little brown bat and the migratory eastern red bat (Lasiurus borealis). These data illustrated the potential for P. destructans to be transferred and dispersed among bats during the summer and highlighted the complex seasonal dynamics associated with this pathogen.
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Observed Resiliency of Little Brown Myotis to Long-Term White-Nose Syndrome Exposure. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2018. [DOI: 10.3996/102017-jfwm-080] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
White-nose syndrome (WNS) is a disease that has killed millions of bats in eastern North America and has steadily been spreading across the continent. Little brown myotis Myotis lucifugus populations have experienced extensive declines; however, some localized populations have remained resilient, with bats surviving multiple years past initial WNS exposure. These persistent populations may be critical to species recovery, and understanding mechanisms leading to this long-term survival and persistence may provide insight into overall bat and disease management. We monitored a maternity colony of little brown myotis on Fort Drum Military Installation in northern New York between 2006 and 2017 to determine basic demographic parameters and find evidence of what may be leading to resiliency and persistence at this site. Total colony size declined by approximately 88% from 2008 to 2010 due primarily to impacts of WNS. Counts of all adults returning to the colony stabilized during 2010–2014 (mean = 94, range 84–101) and increased after 2014 (mean = 132, range = 108–166). We captured 727 little brown myotis (575 females, 152 males) and banded 534 individuals (389 females, 145 males) at the colony. The majority of sampled bats showed evidence of recent past WNS infection and exposure to Pseudogymnoascus destructans, and we documented pervasive presence and limited viability of the fungus within the colony's main roosting structure. We recaptured 98 individually marked females in years after initial banding, and some individuals survived at least 6 y. Ninety-one percent of all adult females, 93% of recaptured bats, and 90% of 1-y-old females (i.e., bats recaptured the first year after initial capture as juveniles) showed evidence of reproduction during the monitoring period. Using mark–recapture models, we estimated annual survival rates of juvenile and adult little brown myotis during 2009–2016 and examined whether reproductive condition or evidence of recent infection of WNS had any effect on survival. Annual survival rates were similar between juveniles and adults, but highly variable, ranging from 41.0 to 86.5%. Models indicated that neither evidence of recent past exposure to WNS nor reproductive status were related to survival. No one parameter stood out as being responsible for this colony's continued existence, and it is likely that many interwoven factors were responsible for the observed resilience. Although relatively high reproductive effort from all females (i.e., both1-y-old and >1-y-old ) and intermittently suitable survival rates have led to the continued persistence of, and population increases in, this summer colony, mortality from WNS and inherently low reproductive potential still seemed to be limiting population growth. Until there is a better understanding of this overall potential resiliency in little brown myotis, we recommend considering minimizing disturbance and direct human involvement within these persisting populations to allow whatever natural recovery that may be occurring to evolve uninterrupted.
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Bernard RF, Willcox EV, Parise KL, Foster JT, McCracken GF. White-nose syndrome fungus, Pseudogymnoascus destructans, on bats captured emerging from caves during winter in the southeastern United States. BMC ZOOL 2017. [DOI: 10.1186/s40850-017-0021-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Fungus Causing White-Nose Syndrome in Bats Accumulates Genetic Variability in North America with No Sign of Recombination. mSphere 2017; 2:mSphere00271-17. [PMID: 28713859 PMCID: PMC5506559 DOI: 10.1128/mspheredirect.00271-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 06/19/2017] [Indexed: 12/17/2022] Open
Abstract
Since its discovery in 2006, the emerging infectious disease known as white-nose syndrome has killed millions of bats in North America, making it one of the most devastating wildlife epidemics in recorded history. We demonstrate that there has been as yet only spontaneous mutation across the North American population of P. destructans, and we find no indication of recombination. Thus, selective forces, which might otherwise impact pathogenic virulence, have so far had essentially no genetic variation on which to act. Our study confirmed the time of origin for the first and, thus far, only introduction of P. destructans to North America. This system provides an unprecedented opportunity to follow the evolution of a host-pathogen interaction unfolding in real time. Emerging fungal diseases of wildlife are on the rise worldwide, and the white-nose syndrome (WNS) epidemic in North American bats is a catastrophic example. The causal agent of WNS is a single clone of the fungus Pseudogymnoascus destructans. Early evolutionary change in this clonal population has major implications for disease ecology and conservation. Accumulation of variation in the fungus through mutation, and shuffling of variation through recombination, could affect the virulence and transmissibility of the fungus and the durability of what appears to be resistance arising in some bat populations. Our genome-wide analysis shows that the clonal population of P. destructans has expanded in size from a single genotype, has begun to accumulate variation through mutation, and presents no evidence as yet of genetic exchange among individuals. IMPORTANCE Since its discovery in 2006, the emerging infectious disease known as white-nose syndrome has killed millions of bats in North America, making it one of the most devastating wildlife epidemics in recorded history. We demonstrate that there has been as yet only spontaneous mutation across the North American population of P. destructans, and we find no indication of recombination. Thus, selective forces, which might otherwise impact pathogenic virulence, have so far had essentially no genetic variation on which to act. Our study confirmed the time of origin for the first and, thus far, only introduction of P. destructans to North America. This system provides an unprecedented opportunity to follow the evolution of a host-pathogen interaction unfolding in real time.
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Lilley TM, Johnson JS, Ruokolainen L, Rogers EJ, Wilson CA, Schell SM, Field KA, Reeder DM. White-nose syndrome survivors do not exhibit frequent arousals associated with Pseudogymnoascus destructans infection. Front Zool 2016; 13:12. [PMID: 26949407 PMCID: PMC4778317 DOI: 10.1186/s12983-016-0143-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/16/2016] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND White-nose syndrome (WNS) has devastated bat populations in North America, with millions of bats dead. WNS is associated with physiological changes in hibernating bats, leading to increased arousals from hibernation and premature consumption of fat reserves. However, there is evidence of surviving populations of little brown myotis (Myotis lucifugus) close to where the fungus was first detected nearly ten years ago. RESULTS We examined the hibernation patterns of a surviving population of little brown myotis and compared them to patterns in populations before the arrival of WNS and populations at the peak of WNS mortality. Despite infection with Pseudogymnoascus destructans, the causative fungal agent, the remnant population displayed less frequent arousals from torpor and lower torpid body temperatures than bats that died from WNS during the peak of mortality. The hibernation patterns of the remnant population resembled pre-WNS patterns with some modifications. CONCLUSIONS These data show that remnant populations of little brown myotis do not experience the increase in periodic arousals from hibernation typified by bats dying from WNS, despite the presence of the fungal pathogen on their skin. These patterns may reflect the use of colder hibernacula microclimates by WNS survivors, and/or may reflect differences in how these bats respond to the disease.
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Affiliation(s)
| | | | - Lasse Ruokolainen
- Department of Biosciences, Faculty of Biological and Environmental Science, Metapopulation Research Centre, University of Helsinki, Viikinkaari 1, Helsinki, Finland
| | | | - Cali Ann Wilson
- Biology Department, Bucknell University, Lewisburg, PA 17837 USA
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Maslo B, Valent M, Gumbs JF, Frick WF. Conservation implications of ameliorating survival of little brown bats with white-nose syndrome. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2015; 25:1832-40. [PMID: 26591449 DOI: 10.1890/14-2472.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Management of wildlife populations impacted by novel threats is often challenged by a lack of data on temporal changes in demographic response. Populations may suffer rapid declines from the introduction of new stressors, but how demography changes over time is critical to determining long-term outcomes for populations. White-nose syndrome (WNS), an infectious disease of hibernating bats, has caused massive and rapid population declines in several hibernating species of bats in North America since the disease was first observed on the continent in 2006. Estimating annual survival rates and demographic trends among remnant colonies of hibernating bats that experienced mass mortality from WNS is needed to determine long-term population viability of species impacted by this disease. Using mark-recapture data on infected little brown bats (Myotis lucifugus), we estimated the first apparent annual survival rates for four years following WNS detection at a site. We found strong support for an increasing trend in annual survival, which improved from 0.68 (95% CI = 0.44-0.85) to 0.75 (95% CI = 0.51-0.89) for males and 0.65 (95% CI = 0.44-0.81) to 0.70 (95% CI = 0.50-0.84) for females. These results suggest that stabilization at remnant colonies after mass mortality from WNS may be due to improved survival and not from immigration from other areas. Despite ameliorating survival, our stochastic matrix projection model predicts continued declines for little brown bat populations (λ = 0.95), raising concern for the regional persistence of this species. We conducted a vital rate sensitivity analysis and determined that adult and juvenile survival, as opposed to fecundity, are the demographic parameters most important to target to maximize recovery potential of little brown bat populations in areas impacted by WNS.
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Johnson JS, Reeder DM, Lilley TM, Czirják GÁ, Voigt CC, McMichael JW, Meierhofer MB, Seery CW, Lumadue SS, Altmann AJ, Toro MO, Field KA. Antibodies to Pseudogymnoascus destructans are not sufficient for protection against white-nose syndrome. Ecol Evol 2015; 5:2203-14. [PMID: 26078857 PMCID: PMC4461422 DOI: 10.1002/ece3.1502] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/22/2015] [Indexed: 12/12/2022] Open
Abstract
White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans (Pd) that affects bats during hibernation. Although millions of bats have died from WNS in North America, mass mortality has not been observed among European bats infected by the fungus, leading to the suggestion that bats in Europe are immune. We tested the hypothesis that an antibody-mediated immune response can provide protection against WNS by quantifying antibodies reactive to Pd in blood samples from seven species of free-ranging bats in North America and two free-ranging species in Europe. We also quantified antibodies in blood samples from little brown myotis (Myotis lucifugus) that were part of a captive colony that we injected with live Pd spores mixed with adjuvant, as well as individuals surviving a captive Pd infection trial. Seroprevalence of antibodies against Pd, as well as antibody titers, was greater among little brown myotis than among four other species of cave-hibernating bats in North America, including species with markedly lower WNS mortality rates. Among little brown myotis, the greatest titers occurred in populations occupying regions with longer histories of WNS, where bats lacked secondary symptoms of WNS. We detected antibodies cross-reactive with Pd among little brown myotis naïve to the fungus. We observed high titers among captive little brown myotis injected with Pd. We did not detect antibodies against Pd in Pd-infected European bats during winter, and titers during the active season were lower than among little brown myotis. These results show that antibody-mediated immunity cannot explain survival of European bats infected with Pd and that little brown myotis respond differently to Pd than species with higher WNS survival rates. Although it appears that some species of bats in North America may be developing resistance to WNS, an antibody-mediated immune response does not provide an explanation for these remnant populations.
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Affiliation(s)
- Joseph S Johnson
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
| | - DeeAnn M Reeder
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
| | | | - Gábor Á Czirják
- Leibniz Institute for Zoo and Wildlife Research Berlin, Germany
| | | | - James W McMichael
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
| | | | | | - Shayne S Lumadue
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
| | | | - Michael O Toro
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
| | - Kenneth A Field
- Department of Biology, Bucknell University Lewisburg, Pennsylvania, 17837
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