scholarly journals Host persistence or extinction from emerging infectious disease: insights from white-nose syndrome in endemic and invading regions

2016 ◽  
Vol 283 (1826) ◽  
pp. 20152861 ◽  
Author(s):  
Joseph R. Hoyt ◽  
Kate E. Langwig ◽  
Keping Sun ◽  
Guanjun Lu ◽  
Katy L. Parise ◽  
...  

Predicting species' fates following the introduction of a novel pathogen is a significant and growing problem in conservation. Comparing disease dynamics between introduced and endemic regions can offer insight into which naive hosts will persist or go extinct, with disease acting as a filter on host communities. We examined four hypothesized mechanisms for host–pathogen persistence by comparing host infection patterns and environmental reservoirs for Pseudogymnoascus destructans (the causative agent of white-nose syndrome) in Asia, an endemic region, and North America, where the pathogen has recently invaded. Although colony sizes of bats and hibernacula temperatures were very similar, both infection prevalence and fungal loads were much lower on bats and in the environment in Asia than North America. These results indicate that transmission intensity and pathogen growth are lower in Asia, likely due to higher host resistance to pathogen growth in this endemic region, and not due to host tolerance, lower transmission due to smaller populations, or lower environmentally driven pathogen growth rate. Disease filtering also appears to be favouring initially resistant species in North America. More broadly, determining the mechanisms allowing species persistence in endemic regions can help identify species at greater risk of extinction in introduced regions, and determine the consequences for disease dynamics and host–pathogen coevolution.

2020 ◽  
Author(s):  
Melissa B. Meierhofer ◽  
Thomas M. Lilley ◽  
Lasse Ruokolainen ◽  
Joseph S. Johnson ◽  
Steven Parratt ◽  
...  

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.


2021 ◽  
Vol 288 (1952) ◽  
pp. 20210719
Author(s):  
Melissa B. Meierhofer ◽  
Thomas M. Lilley ◽  
Lasse Ruokolainen ◽  
Joseph S. Johnson ◽  
Steven R. Parratt ◽  
...  

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.


2014 ◽  
Vol 9 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Konrad Sachanowicz ◽  
Arkadiusz Stępień ◽  
Mateusz Ciechanowski

AbstractPseudogymnoascus destructans (Pd), a parasitic fungus (being responsible for a disease known as white-nose syndrome, WNS) that caused mass mortality of cave-dwelling, hibernating bats in North America, appears to be native of Europe, where it also occurs on wintering bats, but no similar outbreaks of WNS have been recorded. Herein, we provide the first account on prevalence and phenology of P. destructans in Poland. Bats were counted once per month, from October or January to May (2010-2013), in an abandoned ore mine in southern Poland. Presence of P. destructans in two samples was confirmed by sequencing of isolated fungal DNA. Observations of phenotypically identical mycosis on bats hibernating at this site in March 2006 are likely to be the first known records of P. destructans from Poland. All Pd-suspected individuals were Myotis myotis with an exception of one Myotis daubentonii. The first Pd-suspected bats were noted in mid-February, but their number was the highest in March, what overlapped with maximum numbers of hibernating M. myotis. The prevalence in March was 7%–27% of M. myotis individuals. No mass mortality of bats was observed in the mine, with only three dead individuals found in the hibernaculum which hosted up to 130 bats, representing 6–7 species.


mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Kevin P. Drees ◽  
Jeffrey M. Lorch ◽  
Sebastien J. Puechmaille ◽  
Katy L. Parise ◽  
Gudrun Wibbelt ◽  
...  

ABSTRACT Globalization has facilitated the worldwide movement and introduction of pathogens, but epizoological reconstructions of these invasions are often hindered by limited sampling and insufficient genetic resolution among isolates. Pseudogymnoascus destructans , a fungal pathogen causing the epizootic of white-nose syndrome in North American bats, has exhibited few genetic polymorphisms in previous studies, presenting challenges for both epizoological tracking of the spread of this fungus and for determining its evolutionary history. We used single nucleotide polymorphisms (SNPs) from whole-genome sequencing and microsatellites to construct high-resolution phylogenies of P. destructans . Shallow genetic diversity and the lack of geographic structuring among North American isolates support a recent introduction followed by expansion via clonal reproduction across the epizootic zone. Moreover, the genetic relationships of isolates within North America suggest widespread mixing and long-distance movement of the fungus. Genetic diversity among isolates of P. destructans from Europe was substantially higher than in those from North America. However, genetic distance between the North American isolates and any given European isolate was similar to the distance between the individual European isolates. In contrast, the isolates we examined from Asia were highly divergent from both European and North American isolates. Although the definitive source for introduction of the North American population has not been conclusively identified, our data support the origin of the North American invasion by P. destructans from Europe rather than Asia. IMPORTANCE This phylogenetic study of the bat white-nose syndrome agent, P. destructans , uses genomics to elucidate evolutionary relationships among populations of the fungal pathogen to understand the epizoology of this biological invasion. We analyze hypervariable and abundant genetic characters (microsatellites and genomic SNPs, respectively) to reveal previously uncharacterized diversity among populations of the pathogen from North America and Eurasia. We present new evidence supporting recent introduction of the fungus to North America from a diverse Eurasian population, with limited increase in genetic variation in North America since that introduction.


mSphere ◽  
2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Jigar Trivedi ◽  
Josianne Lachapelle ◽  
Karen J. Vanderwolf ◽  
Vikram Misra ◽  
Craig K. R. Willis ◽  
...  

ABSTRACT 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.


EcoHealth ◽  
2021 ◽  
Author(s):  
S. Salleh ◽  
K. Cox-Witton ◽  
Y. Salleh ◽  
Jasmin Hufschmid

AbstractWhite-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans, has caused catastrophic declines of bat populations in North America. Risk assessment indicates that cavers could pose a risk for the spread of the fungus, however, information on cavers’ knowledge of WNS and their caving and biosecurity habits is lacking. An anonymous qualitative survey was completed by delegates (n = 134) from 23 countries at an international speleological conference in Sydney, Australia. Cavers indicated that they visit caves frequently (80.6% at least bimonthly), including outside of their own country, but 20.3% of respondents did not know about WNS prior to the conference. Some respondents were incorrect, or unsure, about whether they had visited caves in countries where P. destructans occurs (26.5%) or whether their own country was free of the fungus (7.8%). Although 65.9% of respondents were aware of current decontamination protocols, only 23.9% and 31.2% (when in Australian or overseas caves, respectively) fully adhered to them. Overall, cavers showed strong willingness to help prevent further spread of this disease, but further efforts at education and targeted biosecurity activities may be urgently needed to prevent the spread of P. destructans to Australia and to other unaffected regions of the world.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jan Zukal ◽  
Hana Bandouchova ◽  
Jiri Brichta ◽  
Adela Cmokova ◽  
Kamil S. Jaron ◽  
...  

Abstract A striking feature of white-nose syndrome, a fungal infection of hibernating bats, is the difference in infection outcome between North America and Europe. Here we show high WNS prevalence both in Europe and on the West Siberian Plain in Asia. Palearctic bat communities tolerate similar fungal loads of Pseudogymnoascus destructans infection as their Nearctic counterparts and histopathology indicates equal focal skin tissue invasiveness pathognomonic for WNS lesions. Fungal load positively correlates with disease intensity and it reaches highest values at intermediate latitudes. Prevalence and fungal load dynamics in Palearctic bats remained persistent and high between 2012 and 2014. Dominant haplotypes of five genes are widespread in North America, Europe and Asia, expanding the source region of white-nose syndrome to non-European hibernacula. Our data provides evidence for both endemicity and tolerance to this persistent virulent fungus in the Palearctic, suggesting that host-pathogen interaction equilibrium has been established.


Virulence ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 781-794 ◽  
Author(s):  
Christina M. Davy ◽  
Michael E. Donaldson ◽  
Hana Bandouchova ◽  
Ana M. Breit ◽  
Nicole A.S. Dorville ◽  
...  

2020 ◽  
Vol 117 (13) ◽  
pp. 7255-7262 ◽  
Author(s):  
Joseph R. Hoyt ◽  
Kate E. Langwig ◽  
Keping Sun ◽  
Katy L. Parise ◽  
Aoqiang Li ◽  
...  

Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of P. destructans in the environment altered infection patterns in bats and influenced whether host populations were stable or experienced severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.


2019 ◽  
Vol 46 (8) ◽  
pp. 657 ◽  
Author(s):  
Peter Holz ◽  
Jasmin Hufschmid ◽  
Wayne S. J. Boardman ◽  
Phillip Cassey ◽  
Simon Firestone ◽  
...  

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.


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