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Ineson KM, O’Shea TJ, Kilpatrick CW, Parise KL, Foster JT. Ambiguities in using telomere length for age determination in two North American bat species. J Mammal 2020. [DOI: 10.1093/jmammal/gyaa064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
AbstractThe age of an animal, determined by time (chronological age) as well as genetic and environmental factors (biological age), influences the likelihood of mortality and reproduction and thus the animal’s contribution to population growth. For many long-lived species, such as bats, a lack of external and morphological indicators has made determining age a challenge, leading researchers to examine genetic markers of age for application to demographic studies. One widely studied biomarker of age is telomere length, which has been related both to chronological and biological age across taxa, but only recently has begun to be studied in bats. We assessed telomere length from the DNA of known-age and minimum known-age individuals of two bat species using a quantitative PCR assay. We determined that telomere length was quadratically related to chronological age in big brown bats (Eptesicus fuscus), although it had little predictive power for accurate age determination of unknown-age individuals. The relationship was different in little brown bats (Myotis lucifugus), where telomere length instead was correlated with biological age, apparently due to infection and wing damage associated with white-nose syndrome. Furthermore, we showed that wing biopsies currently are a better tissue source for studying telomere length in bats than guano and buccal swabs; the results from the latter group were more variable and potentially influenced by storage time. Refinement of collection and assessment methods for different non-lethally collected tissues will be important for longitudinal sampling to better understand telomere dynamics in these long-lived species. Although further work is needed to develop a biomarker capable of determining chronological age in bats, our results suggest that biological age, as reflected in telomere length, may be influenced by extrinsic stressors such as disease.
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Suárez-Esquivel M, Hernández-Mora G, Ruiz-Villalobos N, Barquero-Calvo E, Chacón-Díaz C, Ladner JT, Oviedo-Sánchez G, Foster JT, Rojas-Campos N, Chaves-Olarte E, Thomson NR, Moreno E, Guzmán-Verri C. Persistence of Brucella abortus lineages revealed by genomic characterization and phylodynamic analysis. PLoS Negl Trop Dis 2020; 14:e0008235. [PMID: 32287327 PMCID: PMC7182279 DOI: 10.1371/journal.pntd.0008235] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 04/24/2020] [Accepted: 03/18/2020] [Indexed: 12/27/2022] Open
Abstract
Brucellosis, caused by Brucella abortus, is a major disease of cattle and humans worldwide distributed. Eradication and control of the disease has been difficult in Central and South America, Central Asia, the Mediterranean and the Middle East. Epidemiological strategies combined with phylogenetic methods provide the high-resolution power needed to study relationships between surveillance data and pathogen population dynamics, using genetic diversity and spatiotemporal distributions. This information is crucial for prevention and control of disease spreading at a local and worldwide level. In Costa Rica (CR), the disease was first reported at the beginning of the 20th century and has not been controlled despite many efforts. We characterized 188 B. abortus isolates from CR recovered from cattle, humans and water buffalo, from 2003 to 2018, and whole genome sequencing (WGS) was performed in 95 of them. They were also assessed based on geographic origin, date of introduction, and phylogenetic associations in a worldwide and national context. Our results show circulation of five B. abortus lineages (I to V) in CR, phylogenetically related to isolates from the United States, United Kingdom, and South America. Lineage I was dominant and probably introduced at the end of the 19th century. Lineage II, represented by a single isolate from a water buffalo, clustered with a Colombian sample, and was likely introduced after 1845. Lineages III and IV were likely introduced during the early 2000s. Fourteen isolates from humans were found within the same lineage (lineage I) regardless of their geographic origin within the country. The main CR lineages, introduced more than 100 years ago, are widely spread throughout the country, in contrast to new introductions that seemed to be more geographically restricted. Following the brucellosis prevalence and the farming practices of several middle- and low-income countries, similar scenarios could be found in other regions worldwide.
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Pearson T, Sahl JW, Hepp CM, Handady K, Hornstra H, Vazquez AJ, Settles E, Mayo M, Kaestli M, Williamson CHD, Price EP, Sarovich DS, Cook JM, Wolken SR, Bowen RA, Tuanyok A, Foster JT, Drees KP, Kidd TJ, Bell SC, Currie BJ, Keim P. Pathogen to commensal? Longitudinal within-host population dynamics, evolution, and adaptation during a chronic >16-year Burkholderia pseudomallei infection. PLoS Pathog 2020; 16:e1008298. [PMID: 32134991 PMCID: PMC7077878 DOI: 10.1371/journal.ppat.1008298] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 03/17/2020] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.
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Allen AR, Milne G, Drees K, Presho E, Graham J, McAdam P, Jones K, Wright L, Skuce R, Whatmore AM, Graham J, Foster JT. Genomic epizootiology of a Brucella abortus outbreak in Northern Ireland (1997-2012). INFECTION GENETICS AND EVOLUTION 2020; 81:104235. [PMID: 32035245 DOI: 10.1016/j.meegid.2020.104235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND In the recent past (1997-2012), Northern Ireland in the United Kingdom suffered an outbreak of Brucella abortus, which at its height affected over 200 cattle herds. Initially, isolates were characterized using multi-locus variable number tandem repeats analysis (MLVA). While informative in this setting, hyper-variability in some loci limited the resolution necessary to infer fine-scale disease transmission networks. Consequently, we applied whole-genome sequencing to isolates from this outbreak to evaluate higher resolution markers for disease epizootiology. RESULTS Phylogenetic analysis revealed that the B. abortus outbreak in Northern Ireland was caused by two distinct pathogen lineages. One contained isolates consistent with the 1997-2012 outbreak being linked to a previous endemic infection thought eradicated. The dominant second lineage exhibited little genetic diversity throughout the recrudescent outbreak, with limited population sub-structure evident. This finding was inconsistent with prior MLVA molecular characterizations that suggested the presence of seven clonal complexes. Spatio-temporal modeling revealed a significant association of pairwise SNP differences between isolates and geographic distances. However, effect sizes were very small due to reduced pathogen diversity. CONCLUSIONS Genome sequence data suggested that hyper-variability in some MLVA loci contributed to an overestimate of pathogen diversity in the most recent outbreak. The low diversity observed in our genomic dataset made it inappropriate to apply phylodynamic methods to these data. We conclude that maintaining data repositories of genome sequence data will be invaluable for source attribution/epizootiological inference should recrudescence ever re-occur. However genomic epizootiological methods may have limited utility in some settings, such as when applied to recrudescent/re-emergent infections of slowly-evolving bacterial pathogens.
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Vizentin-Bugoni J, Tarwater CE, Foster JT, Drake DR, Gleditsch JM, Hruska AM, Kelley JP, Sperry JH. Structure, spatial dynamics, and stability of novel seed dispersal mutualistic networks in Hawaiʻi. Science 2019; 364:78-82. [DOI: 10.1126/science.aau8751] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/29/2018] [Accepted: 03/05/2019] [Indexed: 11/02/2022]
Abstract
Increasing rates of human-caused species invasions and extinctions may reshape communities and modify the structure, dynamics, and stability of species interactions. To investigate how such changes affect communities, we performed multiscale analyses of seed dispersal networks on Oʻahu, Hawaiʻi. Networks consisted exclusively of novel interactions, were largely dominated by introduced species, and exhibited specialized and modular structure at local and regional scales, despite high interaction dissimilarity across communities. Furthermore, the structure and stability of the novel networks were similar to native-dominated communities worldwide. Our findings suggest that shared evolutionary history is not a necessary process for the emergence of complex network structure, and interaction patterns may be highly conserved, regardless of species identity and environment. Introduced species can quickly become well integrated into novel networks, making restoration of native ecosystems more challenging than previously thought.
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Koster KJ, Largen A, Foster JT, Drees KP, Qian L, Desmond E, Wan X, Hou S, Douglas JT. Genomic sequencing is required for identification of tuberculosis transmission in Hawaii. BMC Infect Dis 2018; 18:608. [PMID: 30509214 PMCID: PMC6276198 DOI: 10.1186/s12879-018-3502-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/02/2018] [Indexed: 02/08/2023] Open
Abstract
Background Tuberculosis (TB) caused an estimated 1.4 million deaths and 10.4 million new cases globally in 2015. TB rates in the United States continue to steadily decline, yet rates in the State of Hawaii are perennially among the highest in the nation due to a continuous influx of immigrants from the Western Pacific and Asia. TB in Hawaii is composed of a unique distribution of genetic lineages, with the Beijing and Manila families of Mycobacterium tuberculosis (Mtb) comprising over two-thirds of TB cases. Standard fingerprinting methods (spoligotyping plus 24-loci Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats [MIRU-VNTR] fingerprinting) perform poorly when used to identify actual transmission clusters composed of isolates from these two families. Those typing methods typically group isolates from these families into large clusters of non-linked isolates with identical fingerprints. Next-generation whole-genome sequencing (WGS) provides a new tool for molecular epidemiology that can resolve clusters of isolates with identical spoligotyping and MIRU-VNTR fingerprints. Methods We performed WGS and SNP analysis and evaluated epidemiological data to investigate 19 apparent TB transmission clusters in Hawaii from 2003 to 2017 in order to assess WGS’ ability to resolve putative Mtb clusters from the Beijing and Manila families. This project additionally investigated MIRU-VNTR allele prevalence to determine why standard Mtb fingerprinting fails to usefully distinguish actual transmission clusters from these two Mtb families. Results WGS excluded transmission events in seven of these putative clusters, confirmed transmission in eight, and identified both transmission-linked and non-linked isolates in four. For epidemiologically identified clusters, while the sensitivity of MIRU-VNTR fingerprinting for identifying actual transmission clusters was found to be 100%, its specificity was only 28.6% relative to WGS. We identified that the Beijing and Manila families’ significantly lower Shannon evenness of MIRU-VNTR allele distributions than lineage 4 was the cause of standard fingerprinting’s poor performance when identifying transmission in Beijing and Manila family clusters. Conclusions This study demonstrated that WGS is necessary for epidemiological investigation of TB in Hawaii and the Pacific. Electronic supplementary material The online version of this article (10.1186/s12879-018-3502-1) contains supplementary material, which is available to authorized users.
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Hoyt JR, Langwig KE, White JP, Kaarakka HM, Redell JA, Kurta A, DePue JE, Scullon WH, Parise KL, Foster JT, Frick WF, Kilpatrick AM. Cryptic connections illuminate pathogen transmission within community networks. Nature 2018; 563:710-713. [PMID: 30455422 DOI: 10.1038/s41586-018-0720-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 09/24/2018] [Indexed: 01/14/2023]
Abstract
Understanding host interactions that lead to pathogen transmission is fundamental to the prediction and control of epidemics1-5. Although the majority of transmissions often occurs within social groups6-9, the contribution of connections that bridge groups and species to pathogen dynamics is poorly understood10-12. These cryptic connections-which are often indirect or infrequent-provide transmission routes between otherwise disconnected individuals and may have a key role in large-scale outbreaks that span multiple populations or species. Here we quantify the importance of cryptic connections in disease dynamics by simultaneously characterizing social networks and tracing transmission dynamics of surrogate-pathogen epidemics through eight communities of bats. We then compared these data to the invasion of the fungal pathogen that causes white-nose syndrome, a recently emerged disease that is devastating North American bat populations13-15. We found that cryptic connections increased links between individuals and between species by an order of magnitude. Individuals were connected, on average, to less than two per cent of the population through direct contact and to only six per cent through shared groups. However, tracing surrogate-pathogen dynamics showed that each individual was connected to nearly fifteen per cent of the population, and revealed widespread transmission between solitarily roosting individuals as well as extensive contacts among species. Connections estimated from surrogate-pathogen epidemics, which include cryptic connections, explained three times as much variation in the transmission of the fungus that causes white-nose syndrome as did connections based on shared groups. These findings show how cryptic connections facilitate the community-wide spread of pathogens and can lead to explosive epidemics.
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Frick WF, Cheng TL, Langwig KE, Hoyt JR, Janicki AF, Parise KL, Foster JT, Kilpatrick AM. Pathogen dynamics during invasion and establishment of white-nose syndrome explain mechanisms of host persistence. Ecology 2018; 98:624-631. [PMID: 27992970 DOI: 10.1002/ecy.1706] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/30/2016] [Accepted: 12/06/2016] [Indexed: 12/24/2022]
Abstract
Disease dynamics during pathogen invasion and establishment determine the impacts of disease on host populations and determine the mechanisms of host persistence. Temporal progression of prevalence and infection intensity illustrate whether tolerance, resistance, reduced transmission, or demographic compensation allow initially declining populations to persist. We measured infection dynamics of the fungal pathogen Pseudogymnoascus destructans that causes white-nose syndrome in bats by estimating pathogen prevalence and load in seven bat species at 167 hibernacula over a decade as the pathogen invaded, became established, and some host populations stabilized. Fungal loads increased rapidly and prevalence rose to nearly 100% at most sites within 2 yr of invasion in six of seven species. Prevalence and loads did not decline over time despite huge reductions in colony sizes, likely due to an extensive environmental reservoir. However, there was substantial variation in fungal load among sites with persisting colonies, suggesting that both tolerance and resistance developed at different sites in the same species. In contrast, one species disappeared from hibernacula within 3 yr of pathogen invasion. Variable host responses to pathogen invasion require different management strategies to prevent disease-induced extinction and to facilitate evolution of tolerance or resistance in persisting populations.
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Koster K, Largen A, Foster JT, Drees KP, Qian L, Desmond EP, Wan X, Hou S, Douglas JT. Whole genome SNP analysis suggests unique virulence factor differences of the Beijing and Manila families of Mycobacterium tuberculosis found in Hawaii. PLoS One 2018; 13:e0201146. [PMID: 30036392 PMCID: PMC6056056 DOI: 10.1371/journal.pone.0201146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/09/2018] [Indexed: 02/05/2023] Open
Abstract
While tuberculosis (TB) remains a global disease, the WHO estimates that 62% of the incident TB cases in 2016 occurred in the WHO South-East Asia and Western Pacific regions. TB in the Pacific is composed predominantly of two genetic families of Mycobacterium tuberculosis (Mtb): Beijing and Manila. The Manila family is historically under-studied relative to the families that comprise the majority of TB in Europe and North America (e.g. lineage 4), and it remains unclear why this lineage has persisted in Filipino populations despite the predominance of more globally successful Mtb lineages in most of the world. The Beijing family is of particular interest as it is increasingly associated with drug resistance throughout the world. Both of these lineages are important to the State of Hawaii, where they comprise over two-thirds of TB cases. Here, we performed whole genome sequencing on 82 Beijing family, Manila family, and outgroup clinical Mtb isolates from Hawaii to identify lineage-specific SNPs (SNPs found in all isolates from their respective families, and exclusively in those families) in established virulence factor genes. Six non-silent lineage-specific virulence factor SNPs were found in the Beijing family, including mutations in alternative sigma factor sigG and polyketide synthases pks5 and pks7. The Manila family displayed more than eleven non-silent lineage-specific and characteristic virulence factor mutations, including in genes coding for MCE-family protein Mce1B, two mutations in fatty-acid-AMP ligase FadD26, and virulence-regulating transcriptional regulator VirS. This study further identified an ancient clade that shared some virulence factor mutations with the Manila family, and investigated the relationship of those and other “Manila-like” spoligotypes to the Manila family with this SNP dataset. This work identified a set of virulence genes that are worth pursuing to determine potential differences in transmission or virulence displayed by these two Mtb families.
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Campana MG, Kurata NP, Foster JT, Helgen LE, Reeder DM, Fleischer RC, Helgen KM. White-Nose Syndrome Fungus in a 1918 Bat Specimen from France. Emerg Infect Dis 2018; 23:1611-1612. [PMID: 28820367 PMCID: PMC5572869 DOI: 10.3201/eid2309.170875] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
White-nose syndrome, first diagnosed in North America in 2006, causes mass deaths among bats in North America. We found the causative fungus, Pseudogymnoascusdestructans, in a 1918 sample collected in Europe, where bats have now adapted to the fungus. These results are consistent with a Eurasian origin of the pathogen.
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Foster JT, Walker FM, Rannals BD, Hussain MH, Drees KP, Tiller RV, Hoffmaster AR, Al-Rawahi A, Keim P, Saqib M. African Lineage Brucella melitensis Isolates from Omani Livestock. Front Microbiol 2018; 8:2702. [PMID: 29379492 PMCID: PMC5775276 DOI: 10.3389/fmicb.2017.02702] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 12/29/2017] [Indexed: 11/13/2022] Open
Abstract
Brucellosis is a common livestock disease in the Middle East and North Africa, but remains poorly described in the region both genetically and epidemiologically. Traditionally found in goats and sheep, Brucella melitensis is increasingly recognized as infecting camels. Most studies of brucellosis in camels to date have focused on serological surveys, providing only limited understanding of the molecular epidemiology of circulating strains. We genotyped B. melitensis isolates from Omani camels using whole genome SNP assays and VNTRs to provide context for regional brucellosis cases. We identified a lineage of B. melitensis circulating in camels as well as in goats, sheep, and cattle in Oman. This lineage is genetically distinct from most genotypes from the Arabian Peninsula and from isolates from much of the rest of the Middle East. We then developed diagnostic assays that rapidly identify strains from this lineage. In analyses of genotypes from throughout the region, Omani isolates were genetically most closely related to strains from brucellosis cases in humans and livestock in North Africa. Our findings suggest an African origin for B. melitensis in Oman that has likely occurred through the trade of infected livestock. Moreover, African lineages of B. melitensis appear to be undersampled and consequently are underrepresented in genetic databases for Brucella. As we begin to more fully understand global genomic diversity of B. melitensis, finding and characterizing these unique but widespread lineages is essential. We predict that increased sampling of humans and livestock in Africa will reveal little known diversity in this important zoonotic pathogen.
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Palmer JM, Drees KP, Foster JT, Lindner DL. Extreme sensitivity to ultraviolet light in the fungal pathogen causing white-nose syndrome of bats. Nat Commun 2018; 9:35. [PMID: 29295979 PMCID: PMC5750222 DOI: 10.1038/s41467-017-02441-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 11/30/2017] [Indexed: 02/08/2023] Open
Abstract
Bat white-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans, has decimated North American hibernating bats since its emergence in 2006. Here, we utilize comparative genomics to examine the evolutionary history of this pathogen in comparison to six closely related nonpathogenic species. P. destructans displays a large reduction in carbohydrate-utilizing enzymes (CAZymes) and in the predicted secretome (~50%), and an increase in lineage-specific genes. The pathogen has lost a key enzyme, UVE1, in the alternate excision repair (AER) pathway, which is known to contribute to repair of DNA lesions induced by ultraviolet (UV) light. Consistent with a nonfunctional AER pathway, P. destructans is extremely sensitive to UV light, as well as the DNA alkylating agent methyl methanesulfonate (MMS). The differential susceptibility of P. destructans to UV light in comparison to other hibernacula-inhabiting fungi represents a potential “Achilles’ heel” of P. destructans that might be exploited for treatment of bats with WNS. White-nose syndrome, caused by the fungus Pseudogymnoascus destructans, is decimating North American bats. Here, Palmer et al. use comparative genomics to examine the evolutionary history of this pathogen, and show that it has lost a crucial DNA repair enzyme and is extremely sensitive to UV light.
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Langwig KE, Frick WF, Hoyt JR, Parise KL, Drees KP, Kunz TH, Foster JT, Kilpatrick AM. Drivers of variation in species impacts for a multi-host fungal disease of bats. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0456. [PMID: 28080982 DOI: 10.1098/rstb.2015.0456] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2016] [Indexed: 12/22/2022] Open
Abstract
Disease can play an important role in structuring species communities because the effects of disease vary among hosts; some species are driven towards extinction, while others suffer relatively little impact. Why disease impacts vary among host species remains poorly understood for most multi-host pathogens, and factors allowing less-susceptible species to persist could be useful in conserving highly affected species. White-nose syndrome (WNS), an emerging fungal disease of bats, has decimated some species while sympatric and closely related species have experienced little effect. We analysed data on infection prevalence, fungal loads and environmental factors to determine how variation in infection among sympatric host species influenced the severity of WNS population impacts. Intense transmission resulted in almost uniformly high prevalence in all species. By contrast, fungal loads varied over 3 orders of magnitude among species, and explained 98% of the variation among species in disease impacts. Fungal loads increased with hibernating roosting temperatures, with bats roosting at warmer temperatures having higher fungal loads and suffering greater WNS impacts. We also found evidence of a threshold fungal load, above which the probability of mortality may increase sharply, and this threshold was similar for multiple species. This study demonstrates how differences in behavioural traits among species-in this case microclimate preferences-that may have been previously adaptive can be deleterious after the introduction of a new pathogen. Management to reduce pathogen loads rather than exposure may be an effective way of reducing disease impact and preventing species extinctions.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Langwig KE, Hoyt JR, Parise KL, Frick WF, Foster JT, Kilpatrick AM. Resistance in persisting bat populations after white-nose syndrome invasion. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0044. [PMID: 27920389 DOI: 10.1098/rstb.2016.0044] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2016] [Indexed: 01/07/2023] Open
Abstract
Increases in anthropogenic movement have led to a rise in pathogen introductions and the emergence of infectious diseases in naive host communities worldwide. We combined empirical data and mathematical models to examine changes in disease dynamics in little brown bat (Myotis lucifugus) populations following the introduction of the emerging fungal pathogen Pseudogymnoascus destructans, which causes the disease white-nose syndrome. We found that infection intensity was much lower in persisting populations than in declining populations where the fungus has recently invaded. Fitted models indicate that this is most consistent with a reduction in the growth rate of the pathogen when fungal loads become high. The data are inconsistent with the evolution of tolerance or an overall reduced pathogen growth rate that might be caused by environmental factors. The existence of resistance in some persisting populations of little brown bats offers a glimmer of hope that a precipitously declining species will persist in the face of this deadly pathogen.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.
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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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Gleditsch JM, Hruska AM, Foster JT. Connecting Resource Tracking by Frugivores to Temporal Variation in Seed Dispersal Networks. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mahoney SM, Theimer TC, Johnson MJ, Foster JT. Similar dietary but different numerical responses to nonnative tamarisk (Tamarix spp.) by two native warblers. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1408-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Al Dahouk S, Köhler S, Occhialini A, Jiménez de Bagüés MP, Hammerl JA, Eisenberg T, Vergnaud G, Cloeckaert A, Zygmunt MS, Whatmore AM, Melzer F, Drees KP, Foster JT, Wattam AR, Scholz HC. Brucella spp. of amphibians comprise genomically diverse motile strains competent for replication in macrophages and survival in mammalian hosts. Sci Rep 2017; 7:44420. [PMID: 28300153 PMCID: PMC5353553 DOI: 10.1038/srep44420] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/07/2017] [Indexed: 12/31/2022] Open
Abstract
Twenty-one small Gram-negative motile coccobacilli were isolated from 15 systemically diseased African bullfrogs (Pyxicephalus edulis), and were initially identified as Ochrobactrum anthropi by standard microbiological identification systems. Phylogenetic reconstructions using combined molecular analyses and comparative whole genome analysis of the most diverse of the bullfrog strains verified affiliation with the genus Brucella and placed the isolates in a cluster containing B. inopinata and the other non-classical Brucella species but also revealed significant genetic differences within the group. Four representative but molecularly and phenotypically diverse strains were used for in vitro and in vivo infection experiments. All readily multiplied in macrophage-like murine J774-cells, and their overall intramacrophagic growth rate was comparable to that of B. inopinata BO1 and slightly higher than that of B. microti CCM 4915. In the BALB/c murine model of infection these strains replicated in both spleen and liver, but were less efficient than B. suis 1330. Some strains survived in the mammalian host for up to 12 weeks. The heterogeneity of these novel strains hampers a single species description but their phenotypic and genetic features suggest that they represent an evolutionary link between a soil-associated ancestor and the mammalian host-adapted pathogenic Brucella species.
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Hoyt JR, Langwig KE, Sun K, Lu G, Parise KL, Jiang T, Frick WF, Foster JT, Feng J, Kilpatrick AM. Host persistence or extinction from emerging infectious disease: insights from white-nose syndrome in endemic and invading regions. Proc Biol Sci 2016; 283:20152861. [PMID: 26962138 DOI: 10.1098/rspb.2015.2861] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
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.
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Avena CV, Parfrey LW, Leff JW, Archer HM, Frick WF, Langwig KE, Kilpatrick AM, Powers KE, Foster JT, McKenzie VJ. Deconstructing the Bat Skin Microbiome: Influences of the Host and the Environment. Front Microbiol 2016; 7:1753. [PMID: 27909426 PMCID: PMC5112243 DOI: 10.3389/fmicb.2016.01753] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/19/2016] [Indexed: 02/01/2023] Open
Abstract
Bats are geographically widespread and play an important role in many ecosystems, but relatively little is known about the ecology of their associated microbial communities and the role microbial taxa play in bat health, development, and evolution. Moreover, few vertebrate animal skin microbiomes have been comprehensively assessed, and thus characterizing the bat skin microbiome will yield valuable insight into the variability of vertebrate skin microbiomes as a whole. The recent emergence of the skin fungal disease white-nose syndrome highlights the potentially important role bat skin microbial communities could play in bat health. Understanding the determinant of bat skin microbial communities could provide insight into important factors allowing individuals to persist with disease. We collected skin swabs from a total of 11 bat species from the eastern United States (n = 45) and Colorado (n = 119), as well as environmental samples (n = 38) from a subset of sites, and used 16S rRNA marker gene sequencing to observe bacterial communities. In addition, we conducted a literature survey to compare the skin microbiome across vertebrate groups, including the bats presented in this study. Host species, region, and site were all significant predictors of the variability across bat skin bacterial communities. Many bacterial taxa were found both on bats and in the environment. However, some bacterial taxa had consistently greater relative abundances on bat skin relative to their environments. Bats shared many of their abundant taxa with other vertebrates, but also hosted unique bacterial lineages such as the class Thermoleophilia (Actinobacteria). A strong effect of site on the bat skin microbiome indicates that the environment very strongly influences what bacteria are present on bat skin. Bat skin microbiomes are largely composed of site-specific microbiota, but there do appear to be important host-specific taxa. How this translates to differences in host-microbial interactions and bat health remains an important knowledge gap, but this work suggests that habitat variability is very important. We identify some bacterial groups that are more consistent on bats despite site differences, and these may be important ones to study in terms of their function as potential core microbiome members.
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Vogler AJ, Nottingham R, Busch JD, Sahl JW, Shuey MM, Foster JT, Schupp JM, Smith SR, Rocke TE, Keim P, Wagner DM. VNTR diversity in Yersinia pestis isolates from an animal challenge study reveals the potential for in vitro mutations during laboratory cultivation. INFECTION GENETICS AND EVOLUTION 2016; 45:297-302. [PMID: 27664903 DOI: 10.1016/j.meegid.2016.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/30/2016] [Accepted: 09/20/2016] [Indexed: 10/21/2022]
Abstract
Underlying mutation rates and other evolutionary forces shape the population structure of bacteria in nature. Although easily overlooked, similar forces are at work in the laboratory and may influence observed mutations. Here, we investigated tissue samples and Yersinia pestis isolates from a rodent laboratory challenge with strain CO92 using whole genome sequencing and multi-locus variable-number tandem repeat (VNTR) analysis (MLVA). We identified six VNTR mutations that were found to have occurred in vitro during laboratory cultivation rather than in vivo during the rodent challenge. In contrast, no single nucleotide polymorphism (SNP) mutations were observed, either in vivo or in vitro. These results were consistent with previously published mutation rates and the calculated number of Y. pestis generations that occurred during the in vitro versus the in vivo portions of the experiment. When genotyping disease outbreaks, the potential for in vitro mutations should be considered, particularly when highly variable genetic markers such as VNTRs are used.
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Hoyt JR, Sun K, Parise KL, Lu G, Langwig KE, Jiang T, Yang S, Frick WF, Kilpatrick AM, Foster JT, Feng J. Widespread Bat White-Nose Syndrome Fungus, Northeastern China. Emerg Infect Dis 2016; 22:140-2. [PMID: 26673906 PMCID: PMC4698868 DOI: 10.3201/eid2201.151314] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Cheng TL, Mayberry H, McGuire LP, Hoyt JR, Langwig KE, Nguyen H, Parise KL, Foster JT, Willis CKR, Kilpatrick AM, Frick WF. Efficacy of a probiotic bacterium to treat bats affected by the disease white‐nose syndrome. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12757] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Kamath PL, Foster JT, Drees KP, Luikart G, Quance C, Anderson NJ, Clarke PR, Cole EK, Drew ML, Edwards WH, Rhyan JC, Treanor JJ, Wallen RL, White PJ, Robbe-Austerman S, Cross PC. Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock. Nat Commun 2016; 7:11448. [PMID: 27165544 PMCID: PMC4865865 DOI: 10.1038/ncomms11448] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 03/29/2016] [Indexed: 01/09/2023] Open
Abstract
Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.
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Blanchong JA, Robinson SJ, Samuel MD, Foster JT. Application of genetics and genomics to wildlife epidemiology. J Wildl Manage 2016. [DOI: 10.1002/jwmg.1064] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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