White-nose Syndrome and Immune Responses in a Resistant Bat Species (Eptesicus Fuscus) PDF Download

Author: Keslie Naffa
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 88

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Book Description
White-nose syndrome (WNS) has had a large negative impact on bat populations across eastern North America since its arrival in 2006. Bats affected by WNS appear to die of starvation, possibly due to the increased arousals during hibernation when there is no food present to replace the energy used to arouse. During hibernation, the bat’s immune system should be suppressed. However, once a bat of a susceptible species is exposed to the fungus that causes WNS, Psuedogymnoascus destructans (Pd), the immune system seems to respond, potentially causing an elevation in metabolic rate, which may cause the bat to arouse more often. I hypothesize that resistant bats do not mount an immune response; however, if they do mount an immune response, I hypothesize that bats inoculated with Pd and treated with an anti-inflammatory treatment will not respond to the infection, ultimately preserving fat reserves and lowering metabolic expenditures during hibernation. I tested these hypotheses by inoculating a species that does not suffer from high WNS mortality (big brown bats: Eptesicus fuscus), with Pd. Meloxicam was given to one of the three treatment groups in order to suppress the immune system. Metabolic rate during torpor, via oxygen consumption, was measured in addition to arousal/torpor bout patterns, the latter utilizing temperature-sensitive dataloggers. To quantify expression of four immune-function genes (NLRP10, CD200, ICAM5, and TNFRSF21), gene activity was measured via RT-qPCR on tissue and blood samples taken from each bat pre- and post-hibernation. These genes were chosen based on a prior study that showed differences in these genes between susceptible and resistant species. There were no significant differences found across treatment groups for gene expression, nor energetic data; however, hibernation did suppress NLRP10 expression, and blood samples consistently had higher gene expression than tissue samples, thus indicating these genes may be expressed at low levels in some tissues. It is imperative that we continue investigating the differences between susceptible and resistant bat species as WNS is advancing westward throughout the country.

Author: Briana Anderson
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 180

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Book Description
White-nose syndrome (WNS) causes substantial mortality in certain species of hibernating North American bats. The responsible agent is Pseudogymnoascus destructans (Pd), a fungus which causes physiological complications such as increased arousals and energy depletion during the hibernation season. Tricolored bats (Perimyotis subflavus) and northern long-eared bats (Myotis septentrionalis) suffer extensive WNS mortality, while gray bats (Myotis grisescens) and big brown bats (Eptesicus fuscus) are infected, but mortality is rarely observed. It is hypothesized that there is a difference in immune responses and/or hibernation metabolism between these bat species, resulting in this interspecific variation in disease severity. To test these hypotheses, experiments were conducted at both the cellular and whole-bat level. Tricolored bats were infected with Pd and half were treated with an anti-inflammatory to mute any immune response. Data from measurements of torpor energetics did not support the hypothesis, but an immune response was observed in mid-hibernation, based on white blood cell counts. Also, wing tissue fibroblasts from the four species listed above were infected with Pd, and RNA-seq analysis revealed interspecific differences in gene expression in response to Pd. This study could aid in establishing treatment and conservation strategies for North American bats. In addition, a cell culture method has been pioneered that will allow researchers to address a myriad of immunological questions, such as which western bat species might be most susceptible to WNS as it spreads westward.

Author: Tina L. Cheng
Publisher:
ISBN: 9780355334098
Category :
Languages : en
Pages : 122

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Book Description
Emerging infectious diseases can place severe pressures on wildlife populations, leading to major population declines, local extirpation, and species extinctions. However, variability in disease impacts, existing among species and across a spatial and temporal scale, can help us identify species or populations persisting with disease either via resistance, tolerance, pathogen evasion, or by existing within environmental refugia. Understanding mechanisms leading to host persistence can inform conservation management priorities and strategies. White-nose Syndrome (WNS) is a recently emerged disease caused by the fungal pathogen, Pseudogymnoascus destructans (Pd), that has led to severe declines in hibernating bat populations in North America. This work examines patterns and mechanisms associated with variability in WNS impacts with implications for the conservation of affected species. My first chapter investigates spatial heterogeneity in initial impacts of Pd spread across half of continental North America. We found that WNS-related impacts were lessened in the southwestern regions of North America, suggesting potential spatial refugia from WNS-related impacts but only for Perimyotis subflavus. We found that annual air surface temperatures driving Pd growth explained, in part, this spatial variation in WNS-related impacts. Despite evidence for lessened WNS-related declines in the southwest, impacts to bat populations are severe throughout North America for most bat species. My second chapter examines colonies of M. lucifugus that have experienced variability in declines over time, persisting potentially due to host-specific responses. Specifically, I investigate if differences in early winter fat reserves could explain survivorship and persistence of M. lucifugus colonies with WNS. We found that bats persisting with WNS in 2016 were significantly fatter than bats colonies sampled during WNS arrival in 2008 and 2009 at four out of our six sampled sites. At another two sites, we found that bats were either fatter in 2008 and 2009 compared to 2016. We used hibernation energetic models to estimate the amount of fat afforded to survival and found that increased fat reserves from bats measured in 2016 could reduce mortality by 65%. These data suggest that increased fat reserves can explain, in part, the persistence of M. lucifugus colonies with WNS. Lastly, my third chapter experimentally investigates one possible cause of variability in WNS impacts, variation host susceptibility via protective bacteria in the skin microbiome. In this chapter, I explore the efficacy of using a probiotic bacterium, harvested from the skin of a species experiencing lessened WNS impacts, Eptesicus fuscus , as a conservation tool applied to a more highly affected bat species, M. lucifugus. We found relative increases in survival for probiotic-treated groups compared to our sham control group. We also found evidence for decreased fungal infection and severity in probiotic-treated groups. Our results suggest that probiotic treatment can reduce incidence of White-nose Syndrome in M. lucifugus although timing of treatment is an important factor. Together, this work finds that variability in spatial, species-specific, and temporal impacts from WNS can inform conservation efforts. Namely, this work suggests that bat conservation should involve a multi-pronged approach that protects colonies where bats are persisting with WNS via habitat restoration, and potentially treating bats for threatened populations not persisting with WNS. Given the continued threat of WNS to bats as it spreads throughout North America, using a variety of tools to combat this disease may be critical to prevent disease-induced extinction and the local extirpation of affected bat species.

Author: Amanda Frances Janicki
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 24

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Book Description
White-Nose Syndrome (WNS) is an epizootic disease in hibernating bats caused by the fungus Pseudogymnoascus destructans. Surveillance for P. destructans at bat hibernacula consists primarily of visual surveys of bats, collection of potentially infected bats, and submission of these bats for laboratory testing. Cryptic infections (bats that are infected but display no visual signs of fungus) could lead to the mischaracterization of the infection status of a site and the inadvertent spread of P. destructans. We determined the efficacy of visual detection of P. destructans by examining visual signs and molecular detection of P. destructans on 928 bats of six species at 27 sites during surveys conducted from January through March in 2012–2014 in the southeastern USA on the leading edge of the disease invasion. Cryptic infections were widespread with 77% of bats that tested positive by qPCR showing no visible signs of infection. The probability of exhibiting visual signs of infection increased with sampling date and pathogen load, the latter of which was substantially higher in three species (Myotis lucifugus, M. septentrionalis, and Perimyotis subflavus). In addition, M. lucifugus was more likely to show visual signs of infection than other species given the same pathogen load. Nearly all infections were cryptic in three species (Eptesicus fuscus, M. grisescens, and M. sodalis), which had much lower fungal loads. The presence of M. lucifugus or M. septentrionalis at a site increased the probability that P. destructans was visually detected on bats. Our results suggest that cryptic infections of P. destructans are common in all bat species, and visible infections rarely occur in some species. However, due to very high infection prevalence and loads in some species, we estimate that visual surveys examining at least 17 individuals of M. lucifugus and M. septentrionalis, or 29 individuals of P. subflavus are still effective to determine whether a site has bats infected with P. destructans. In addition, because the probability of visually detecting the fungus was higher later in winter, surveys should be done as close to the end of the hibernation period as possible.

Author: Christian C. Voigt
Publisher: Springer
ISBN: 3319252208
Category : Nature
Languages : en
Pages : 601

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Book Description
This book focuses on central themes related to the conservation of bats. It details their response to land-use change and management practices, intensified urbanization and roost disturbance and loss. Increasing interactions between humans and bats as a result of hunting, disease relationships, occupation of human dwellings, and conflict over fruit crops are explored in depth. Finally, contributors highlight the roles that taxonomy, conservation networks and conservation psychology have to play in conserving this imperilled but vital taxon. With over 1300 species, bats are the second largest order of mammals, yet as the Anthropocene dawns, bat populations around the world are in decline. Greater understanding of the anthropogenic drivers of this decline and exploration of possible mitigation measures are urgently needed if we are to retain global bat diversity in the coming decades. This book brings together teams of international experts to provide a global review of current understanding and recommend directions for future research and mitigation.

Author: Molly C. Simonis
Publisher:
ISBN:
Category : Biology
Languages : en
Pages : 0

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Book Description
Disturbances in environment can lead to a wide range of host physiological responses. These responses can either allow hosts to adjust to new conditions in their environment or can reduce their survival, and can subsequently cause host traits to shift. Small mammals are particularly vulnerable to stochastic disturbances, like a pathogen introduction, because of their high energy demands. Studies examining host responses to pathogens often focus on species highly susceptible to infection that typically have high mortality rates, leading to a gap in understanding the responses of less susceptible species. My dissertation evaluates the energy balance of Eptesicus fuscus (big brown bats), a species considered less susceptible to the introduced fungal pathogen Pseudogymnoascus destructans (Pd) which causes white-nose syndrome in North American hibernating bats. I quantified changes in body mass, energy expenditures and the abundance of E. fuscus over long-term Pd exposure time. Using 30 years of data for 24,129 individual E. fuscus captures across the eastern US, I found E. fuscus body mass decreased with increasing latitude once Pd was established on the landscape (5+ years). When measuring whole-animal energy expenditures of 19 E. fuscus in lab settings using open-flow respirometry, I found that E. fuscus with long-term exposure to Pd have increases or no change to torpid metabolic rates across a wide range of ambient temperatures. Finally, the overall abundance of E. fuscus increased with Pd exposure, and lactating and post-lactating bats increased abundance with increasing latitude in the eastern US. Taken together, these results suggest that E. fuscus may have a combination of pathogen and intraspecific competitive pressures impacting their populations, particularly in northern latitudes. This dissertation highlights how introduced pathogens can cause spatially variable responses in less susceptible hosts over time, and other ecological pressures may contribute to those responses. Future efforts for understanding the degree of persistence of less susceptible wildlife host populations are critical for predicting how and why their populations change following emerging infectious disease outbreaks and epidemics.

Author: Derek Morningstar
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Competition is commonly invoked to explain variation in abundance, activity patterns, and resource use, but is difficult to detect in nature. Introduction of white-nose syndrome (WNS) in bats provides a natural experiment to test the impact of interspecific competition on bat communities. Acoustic monitoring at locations in Southern Ontario showed an increase in activity of Big Brown Bats (Eptesicus fuscus) and corresponding decline in the activity of Little Brown Myotis (Myotis lucifugus), following the introduction of WNS. Next generation sequencing of bat stomachs and guano in Southern Ontario before and after WNS allowed for the characterization of diet changes of these species. As a function of competitive release, E. fuscus consumed a wider breadth of prey and many of the insect species once consumed by M. lucifugus, including several pest insects. These results suggest that interspecific competition has a detectable effect on bat communities in Southern Ontario.

Author:
Publisher:
ISBN:
Category : Bats
Languages : en
Pages : 16

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Book Description
“White-nose syndrome” (WNS) is an emerging fungal disease of hibernating North American bat species. To date, WNS has likely killed between 5.7 and 6.7 million hibernating bats in caves and inactive mines in the eastern USA, and has contributed to the imperilment of some bat populations and species. The WNS fungus (Geomyces destructans) has the potential to kill individuals of many of the 18 bat species native to Colorado. Bats are ecologically and economically important, and measures to prevent the spread of WNS and minimize its impacts on native bat species are clearly warranted.

Author: Shie-Liang Hsieh
Publisher: Springer Nature
ISBN: 9811515808
Category : Medical
Languages : en
Pages : 240

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Book Description
This book systemically presents the latest research on lectins, covering all the major topics in the field, including the heterocomplex of lectins and Toll-like receptors, protective versus pathogenic functions in connection with microbial infections, and novel strategies for enhancing host immunity against infectious diseases caused by viruses, bacteria, and fungi. Lectins are a large group of glycan-binding proteins that recognize diverse glycan and non-glycan structures expressed on prokaryotic and eukaryotic cells, and are vital to cell-cell interactions, the attachment of microbes to host cells, and the recognition and activation of immune responses to exogenous and endogenous danger signals. The composition and structure of microbes are complex and include numerous ‘pathogen-associated molecular patterns’ or ‘damage-associated molecular patterns’. As such, microbes’ interactions with immune cells activate multiple innate immunity receptors and produce distinct inflammatory reactions, which can be protective to contain microbial invasion, or pathogenic to cause tissue damage and shock syndrome in the host. The book shares lessons learned from state-of-the art research in this field, highlights the latest discoveries, and provides insightful discussions on lectin-mediated inflammatory reactions, while also outlining future research directions.

Author: Marianne Gagnon
Publisher:
ISBN:
Category :
Languages : en
Pages : 137

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Book Description
Emerging infectious diseases of wildlife are among the greatest threats to biodiversity. Indeed, when pathogens are introduced into naïve host populations, they can impose novel selective pressures that may cause severe host declines or even extinction. However, disease impacts may vary both within and among host species. Thus, one of the key goals for management is to identify factors that drive variation in host susceptibility to infection, as they may improve our understanding of hosts' potential to develop disease resistance and/or tolerance and inform conservation strategies aimed at facilitating host persistence. For instance, Pseudogymnoascus destructans (Pd) - an invasive pathogenic fungus that causes white-nose syndrome (WNS) in hibernating bats - is highly virulent, has killed millions of bats in North America, and continues to spread at an alarming rate. Yet, the continued persistence of bat colonies in contaminated areas despite initial mass mortality events suggests variation in survival among infected individuals. I thus aimed to better understand intraspecific drivers of variation in bat susceptibility to WNS and their implications for population persistence and management in affected areas. Specifically, my objectives were to: 1) evaluate the extent to which variation in hibernaculum microclimate temperature and humidity affects Pd infection severity and disease progression in affected bats during hibernation, 2) compare how bats from colonies that vary in duration of exposure to Pd and from different age classes behaviorally respond to the infection, and examine how these behavioral changes affect host fitness and 3) model the population dynamics of remnant bat populations to assess the likeliness of persistence and the potential effectiveness of management interventions in affected colonies. I addressed these objectives through field research, experimental infection studies, and demographic modeling of the little brown myotis (Myotis lucifugus). In my dissertation, I first provide causal evidence of environmentally-driven variation in pathogen growth and infection severity on bats in the field. Both warmer and more humid microclimates contribute to the severity of the infection by promoting the production of conidia, the erosion of wing tissues, and, therefore, the transmission potential and virulence of Pd. I then document potential mechanistic links between Pd-induced behavioral change and host fitness. Higher infection levels, independent of bats' past exposure to Pd or age class, may cause individuals to groom longer, prolong euthermic arousals, accelerate the depletion of fat reserves, and ultimately increase mortality risk. Finally, I predict that populations will face a high risk of extirpation in the next decade or two if no management action is taken, but that interventions such as environmental control of Pd and hibernaculum microclimate manipulation can prevent short-term population collapse in remnant bat populations. Together, these studies provide key, mechanistic insight into the pathology of WNS and the probability of persistence of affected bat colonies, while highlighting the importance of prioritizing winter habitat preservation and enhancement for the conservation of hibernating bats.