scholarly journals Experimental evaluation of genomic DNA degradation rates for the pathogen Pseudogymnoascus destructans (Pd) in bat guano

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8141
Author(s):  
Jenny Urbina ◽  
Tara Chestnut ◽  
Donelle Schwalm ◽  
Jenn Allen ◽  
Taal Levi
Keyword(s):  
North America ◽  
Environmental Conditions ◽  
Large Scale ◽  
Environmental Dna ◽  
Sampling Period ◽  
Dna Degradation ◽  
Washington State ◽  
Extracellular Dna ◽  
Pseudogymnoascus Destructans ◽  
Degradation Rates

Pseudogymnoascus destructans (Pd), the causative agent of white-nose syndrome in bats (WNS), has led to dramatic declines of bat populations in eastern North America. In the spring of 2016, WNS was first detected at several locations in Washington State, USA, which has prompted the need for large scale surveillance efforts to monitor the spread of Pd. Pd is typically detected in bats using invasive methods requiring capturing and swabbing individual bats. However, Pd can also be detected in guano, which may provide an efficient, affordable, and noninvasive means to monitor Pd in bats across North America. The widespread implementation of Pd surveillance in guano is hindered by substantial uncertainty about the probability of detecting Pd when present, and how this probability is influenced by the time since defecation, local environmental conditions, the amount of guano sampled, and the original concentration of DNA shed in the guano. In addition, the expected degradation rate of Pd DNA depends on whether the Pd DNA found in guano represents extracellular DNA fragments, intracellular DNA from dead Pd fungal cells, or from intracellular and viable Pd cells. While this is currently unknown, it has been posited that most environmental DNA, such as Pd found in guano long after defecation, is fragmented extracellular DNA. Using non-viable isolated DNA at precise quantities, we experimentally characterized the degradation rates of Pd DNA in guano samples. We spiked 450 guano samples with Pd gDNA in a 10-fold dilution series from 1 million to 1,000 fg and placed them in variable environmental conditions at five sites at Mount Rainier National Park in Washington State, which is a priority location for Pd surveillance. We evaluated DNA degradation over 70 days by quantifying the amount of DNA in samples collected every 14 days using real-time quantitative PCR (qPCR). Our sampling period was from July 10th to September 17th 2018 which overlaps with bat movement between summer roosts as well as movement from maternity colonies fall swarms. We detected Pd DNA in guano 56 and 70 days after inoculation with 1 million and 100,000 fg respectively, while the lowest quantity (1,000 fg) was detected until 42 days. Detection probability was variable among sites and lower where samples were left exposed without overhead cover. If Pd is shed as extracellular DNA in guano at quantities above 1,000 fg, then guano collection is likely to provide an effective tool for environmental screening of Pd that can be employed in an early detection and rapid response framework throughout Washington and other regions where this disease is rapidly emerging.

scholarly journals Ten-year projection of white-nose syndrome disease dynamics at the southern leading-edge of infection in North America

2020 ◽  
Author(s):  
Melissa B. Meierhofer ◽  
Thomas M. Lilley ◽  
Lasse Ruokolainen ◽  
Joseph S. Johnson ◽  
Steven Parratt ◽  
...  
Keyword(s):  
Infectious Disease ◽  
North America ◽  
Environmental Conditions ◽  
Leading Edge ◽  
Environmental Data ◽  
Disease Spread ◽  
Disease Dynamics ◽  
Pseudogymnoascus Destructans ◽  
White Nose Syndrome ◽  
Management Actions

AbstractPredicting the emergence and spread of infectious diseases is critical for effective conservation of biodiversity. White-nose syndrome (WNS), an emerging infectious disease of bats, has resulted in high mortality in eastern North America. Because the fungal causative agent Pseudogymnoascus destructans is constrained by temperature and humidity, spread dynamics may vary greatly by geography. Environmental conditions in the southern part of the continent, where disease dynamics are typically studied, making it difficult to predict how the disease will manifest. Herein, we modeled the spread of WNS in Texas based on available cave densities and average dispersal distances of species occupying these sites, and projected these results out to 10 years. We parameterized a predictive model of WNS epidemiology and its effects on hibernatory bat populations with observed environmental data from bat hibernation sites in Texas. Our model suggests that bat populations in northern Texas will be more affected by WNS mortality than southern Texas. As such, we recommend prioritizing the preservation of large overwintering colonies of bats in north Texas through management actions. Our model further illustrates that infectious disease spread and infectious disease severity can become uncoupled over a gradient of environmental variation. Finally, our results highlight the importance of understanding host, pathogen and environmental conditions in various settings to elucidate what may happen across a breadth of environments.

Does the fungus causing white-nose syndrome pose a significant risk to Australian bats?

2019 ◽  
Vol 46 (8) ◽  
pp. 657 ◽  
Author(s):  
Peter Holz ◽  
Jasmin Hufschmid ◽  
Wayne S. J. Boardman ◽  
Phillip Cassey ◽  
Simon Firestone ◽  
...  
Keyword(s):  
North America ◽  
Large Scale ◽  
Risk Mitigation ◽  
Significant Risk ◽  
Mitigation Strategies ◽  
Pseudogymnoascus Destructans ◽  
Term Survival ◽  
White Nose Syndrome ◽  
Scale Population ◽  
Risk Mitigation Strategies

Abstract ContextPseudogymnoascus destructans is the fungus responsible for white-nose syndrome (WNS), which has killed millions of hibernating bats in North America, but also occurs in bats in Europe and China without causing large-scale population effects. This is likely to be due to differences in species susceptibility and behaviour, and environmental factors, such as temperature and humidity. Pseudogymnoascus destructans is currently believed to be absent from Australia. AimsTo ascertain the level of risk that white-nose syndrome poses for Australian bats. Methods This risk analysis examines the likelihood that P. destructans enters Australia, the likelihood of the fungus coming in contact with native bats on successful entry, and the potential consequences should this occur. Key results This risk assessment concluded that it is very likely to almost certain that P. destructans will enter Australia, and it is likely that bats will be exposed to the fungus over the next 10 years. Eight cave-dwelling bat species from southern Australia are the ones most likely to be affected. ConclusionsThe risk was assessed as medium for the critically endangered southern bent-winged bat (Miniopterus orianae bassanii), because any increase in mortality could affect its long-term survival. The risk to other species was deemed to range from low to very low, owing to their wider distribution, which extends beyond the P. destructans risk zone. Implications Although Australia’s milder climate may preclude the large mortality events seen in North America, the fungus could still significantly affect Australian bat populations, particularly bent-winged bats. Active surveillance is required to confirm Australia’s continuing WNS-free status, and to detect the presence of P. destructans should it enter the country. Although White-nose Syndrome Response Guidelines have been developed by Wildlife Health Australia to assist response agencies in the event of an incursion of WNS into bats in Australia, these guidelines would be strengthened by further research to characterise Australian cave temperatures and hibernating bat biology, such as length of torpor bouts and movement over winter. Risk-mitigation strategies should focus on education programs that target cavers, show-cave managers and tourists, particularly those who have visited regions where WNS is known to occur.

scholarly journals Predicting the strength of urban-rural clines in a Mendelian polymorphism along a latitudinal gradient

2019 ◽  
Author(s):  
James S. Santangelo ◽  
Ken A. Thompson ◽  
Beata Cohan ◽  
Jibran Syed ◽  
Rob W. Ness ◽  
...  
Keyword(s):  
North America ◽  
White Clover ◽  
Environmental Conditions ◽  
Hydrogen Cyanide ◽  
Large Scale ◽  
Parallel Evolution ◽  
Urban Environments ◽  
Eastern North America ◽  
Scale Models ◽  
Urban Rural

AbstractCities are emerging as models for addressing the fundamental question of whether populations evolve in parallel to similar environments. Here, we examine the environmental factors that drive parallel evolutionary urban-rural clines in a Mendelian trait — the cyanogenic antiherbivore defense of white clover (Trifolium repens). We sampled over 700 urban and rural clover populations across 16 cities along a latitudinal transect in eastern North America. In each population, we quantified the frequency of genotypes that produce hydrogen cyanide (HCN), and in a subset of the cities we estimated the frequency of the alleles at the two genes (CYP79D15 and Li) that epistatically interact to produce HCN. We then tested the hypothesis that winter environmental conditions cause the evolution of clines in HCN by comparing the strength of clines among cities located along a gradient of winter temperatures and frost exposure. Overall, half of the cities exhibited urban-rural clines in the frequency of HCN, whereby urban populations evolved lower HCN frequencies. The weakest clines in HCN occurred in cities with the lowest temperatures but greatest snowfall, supporting the hypothesis that snow buffers plants against winter frost and constrains the formation of clines. By contrast, the strongest clines occurred in the warmest cities where snow and frost are rare, suggesting that alternative selective agents are maintaining clines in warmer cities. Additionally, some clines were driven by evolution at only CYP79D15, consistent with stronger and more consistent selection on this locus than on Li. Together, our results demonstrate that both the agents and targets of selection vary across cities and highlight urban environments as large-scale models for disentangling the causes of parallel evolution in nature.Impact SummaryUnderstanding whether independent populations evolve in the same way (i.e., in parallel) when subject to similar environments remains an important problem in evolutionary biology. Urban environments are a model for addressing the extent of parallel evolution in nature due to their convergent environments (e.g. heat islands, pollution, fragmentation), such that two distant cities are often more similar to one another than either is to nearby nonurban habitats. In this paper, we used white clover (Trifolium repens) as a model to study the drivers of parallel evolution in response to urbanization. We collected >11,000 plants from urban and rural habitats across 16 cities in eastern North America to examine how cities influence the evolution of a Mendelian polymorphism for an antiherbivore defense trait – hydrogen cyanide (HCN). This trait had previously been shown to exhibit adaptive evolution to winter temperature gradients at continental scales. Here we tested the hypothesis that winter environmental conditions cause changes in the frequency of HCN between urban and rural habitats. We found that half of all cities had lower frequency of HCN producing genotypes relative to rural habitats, demonstrating that cities drive parallel losses of HCN in eastern North America. We then used environmental data to understand why cities vary in the extent to which they drive reduction in HCN frequencies. The warmest cities showed the greatest reductions in HCN frequencies in urban habitats, while colder, snowier cities showed little change in HCN between urban and rural habitats. This suggests that snow weakens the strength of natural selection against HCN in cities. However, it additionally suggests alternative ecological or evolutionary mechanisms drive the strong differences in HCN between urban and rural habitats in the warmest cities. Overall, our work highlights urban environments as powerful, large-scale models for disentangling the causes of parallel and non-parallel evolution in nature.

scholarly journals Metabarcoding on the deep seafloor: optimizing multigene approaches and sampling methods for large-scale biodiversity assessments.

2018 ◽  
Author(s):  
Miriam I Brandt ◽  
Daniela Zeppilli ◽  
Caroline Dussart ◽  
Erwan Aublet ◽  
Florence Pradillon ◽  
...  
Keyword(s):  
Deep Sea ◽  
Large Scale ◽  
Sampling Methods ◽  
Environmental Dna ◽  
Ecological Impacts ◽  
Extracellular Dna ◽  
Baseline Knowledge ◽  
Ecosystem Diversity ◽  
Central Atlantic ◽  
Large Scale Project

The deep sea, the largest and most poorly known biome on Earth, is under increasing threat from human-induced ecological impacts. Improved baseline knowledge and environmental impact assessment protocols are required to be able to alleviate potential changes in ecosystem diversity and functioning in the deep-sea. Metabarcoding of environmental DNA (eDNA) enables broader and faster biodiversity assessments, and is increasingly used to study eukaryote and prokaryote diversity. Whether metabarcoding provides reliable diversity inventories that meet the quality standards for accurate baseline data and biomonitoring is still uncertain in the deep-sea benthos, the latter being associated with specific taxonomic and sampling challenges. In particular, it is crucial to develop multigene metabarcoding protocols targeting living organisms and not extracellular, archived DNA. Before launching a large-scale project for the reassessment of deep-sea biodiversity, we addressed these technical challenges using bathyal and abyssal sediments sampled in the Mediterranean and central Atlantic. Our aim was to setup optimized protocols and evaluate the strengths and limitations of multigene metabarcoding in the deep sea by 1) comparing eDNA-based with traditional morphology-based diversity inventories and 2) assessing the accuracy and/or bias associated with distinct sample processing methods, including RNA and size-selected DNA extracts lacking short (extracellular) DNA fragments.

scholarly journals Ten-year projection of white-nose syndrome disease dynamics at the southern leading-edge of infection in North America

2021 ◽  
Vol 288 (1952) ◽  
pp. 20210719
Author(s):  
Melissa B. Meierhofer ◽  
Thomas M. Lilley ◽  
Lasse Ruokolainen ◽  
Joseph S. Johnson ◽  
Steven R. Parratt ◽  
...  
Keyword(s):  
Infectious Disease ◽  
North America ◽  
Environmental Conditions ◽  
Leading Edge ◽  
Environmental Data ◽  
Disease Spread ◽  
Disease Dynamics ◽  
Pseudogymnoascus Destructans ◽  
White Nose Syndrome ◽  
Management Actions

Predicting the emergence and spread of infectious diseases is critical for the effective conservation of biodiversity. White-nose syndrome (WNS), an emerging infectious disease of bats, has resulted in high mortality in eastern North America. Because the fungal causative agent Pseudogymnoascus destructans is constrained by temperature and humidity, spread dynamics may vary by geography. Environmental conditions in the southern part of the continent are different than the northeast, where disease dynamics are typically studied, making it difficult to predict how the disease will manifest. Herein, we modelled WNS pathogen spread in Texas based on cave densities and average dispersal distances of hosts, projecting these results out to 10 years. We parameterized a predictive model of WNS epidemiology and its effects on bat populations with observed cave environmental data. Our model suggests that bat populations in northern Texas will be more affected by WNS mortality than southern Texas. As such, we recommend prioritizing the preservation of large overwintering colonies of bats in north Texas through management actions. Our model illustrates that infectious disease spread and infectious disease severity can become uncoupled over a gradient of environmental variation and highlight the importance of understanding host, pathogen and environmental conditions across a breadth of environments.

scholarly journals Metabarcoding on the deep seafloor: optimizing multigene approaches and sampling methods for large-scale biodiversity assessments.

2018 ◽  
Author(s):  
Miriam I Brandt ◽  
Daniela Zeppilli ◽  
Caroline Dussart ◽  
Erwan Aublet ◽  
Florence Pradillon ◽  
...  
Keyword(s):  
Deep Sea ◽  
Large Scale ◽  
Sampling Methods ◽  
Environmental Dna ◽  
Ecological Impacts ◽  
Extracellular Dna ◽  
Baseline Knowledge ◽  
Ecosystem Diversity ◽  
Central Atlantic ◽  
Large Scale Project

The deep sea, the largest and most poorly known biome on Earth, is under increasing threat from human-induced ecological impacts. Improved baseline knowledge and environmental impact assessment protocols are required to be able to alleviate potential changes in ecosystem diversity and functioning in the deep-sea. Metabarcoding of environmental DNA (eDNA) enables broader and faster biodiversity assessments, and is increasingly used to study eukaryote and prokaryote diversity. Whether metabarcoding provides reliable diversity inventories that meet the quality standards for accurate baseline data and biomonitoring is still uncertain in the deep-sea benthos, the latter being associated with specific taxonomic and sampling challenges. In particular, it is crucial to develop multigene metabarcoding protocols targeting living organisms and not extracellular, archived DNA. Before launching a large-scale project for the reassessment of deep-sea biodiversity, we addressed these technical challenges using bathyal and abyssal sediments sampled in the Mediterranean and central Atlantic. Our aim was to setup optimized protocols and evaluate the strengths and limitations of multigene metabarcoding in the deep sea by 1) comparing eDNA-based with traditional morphology-based diversity inventories and 2) assessing the accuracy and/or bias associated with distinct sample processing methods, including RNA and size-selected DNA extracts lacking short (extracellular) DNA fragments.

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