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McGrath-Blaser SE, McGathey N, Pardon A, Hartmann AM, Longo AV. Invasibility of a North American soil ecosystem to amphibian-killing fungal pathogens. Proc Biol Sci 2024; 291:20232658. [PMID: 38628130 PMCID: PMC11021929 DOI: 10.1098/rspb.2023.2658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
North American salamanders are threatened by intercontinental spread of chytridiomycosis, a deadly disease caused by the fungal pathogen Batrachochytrium salamandrivorans (Bsal). To predict potential dispersal of Bsal spores to salamander habitats, we evaluated the capacity of soil microbial communities to resist invasion. We determined the degree of habitat invasibility using soils from five locations throughout the Great Smoky Mountains National Park, a region with a high abundance of susceptible hosts. Our experimental design consisted of replicate soil microcosms exposed to different propagule pressures of the non-native pathogen, Bsal, and an introduced but endemic pathogen, B. dendrobatidis (Bd). To compare growth and competitive interactions, we used quantitative PCR, live/dead cell viability assays, and full-length 16S rRNA sequencing. We found that soil microcosms with intact bacterial communities inhibited both Bsal and Bd growth, but inhibitory capacity diminished with increased propagule pressure. Bsal showed greater persistence than Bd. Linear discriminant analysis (LDA) identified the family Burkolderiaceae as increasing in relative abundance with the decline of both pathogens. Although our findings provide evidence of environmental filtering in soils, such barriers weakened in response to pathogen type and propagule pressure, showing that habitats vary their invasibility based on properties of their local microbial communities.
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Affiliation(s)
| | - Natalie McGathey
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Allison Pardon
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Arik M. Hartmann
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Ana V. Longo
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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Bodinof Jachowski CM, Alaasam V, Blumenthal A, Davis AK, Hopkins WA. The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian. CONSERVATION PHYSIOLOGY 2024; 12:coad101. [PMID: 38293638 PMCID: PMC10823334 DOI: 10.1093/conphys/coad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/17/2023] [Accepted: 11/28/2023] [Indexed: 02/01/2024]
Abstract
Amphibian declines are a global phenomenon but responses of populations to specific threats are often context dependent and mediated by individual physiological condition. Habitat degradation due to reduced riparian forest cover and parasitism are two threats facing the hellbender salamander (Cryptobranchus alleganiensis), but their potential to interact in nature remains largely unexplored. We investigated associations between forest cover, parasitic infection and physiology of hellbenders to test the hypotheses that physiological condition responds to infection and/or habitat degradation. We sampled 17 stream reaches in southwest Virginia, USA, on a year-round basis from 2013 to 2016 and recorded 841 captures of 405 unique hellbenders. At each capture we documented prevalence of two blood-associated parasites (a leech and trypanosome) and quantified up to three physiological condition indices (body condition, hematocrit, white blood cell [WBC] differentials). We used generalized linear mixed models to describe spatiotemporal variation in parasitic infection and each condition index. In general, living in the most heavily forested stream reaches, where hellbender density was highest, was associated with the greatest risk of parasitism, elevated neutrophil-to-lymphocyte (N:L) ratios and eosinophils, slightly lower hematocrit and lower mean body condition in hellbenders. All condition indices fluctuated temporally in a manner consistent with seasonal variation in hellbender metabolic demands and breeding phenology and were associated with land use during at least part of the year. Paradoxically, relatively low levels of forest cover appeared to confer a potential advantage to individuals in the form of release from parasites and improved body condition. Despite improved body condition, individuals from less forested areas failed to exhibit fluctuating body condition in response to spawning, which was typical in hellbenders from more forested habitats. We postulate this lack of fluctuation could be due to reduced conspecific competition or reproductive investment and/or high rates of filial cannibalism in response to declining forest cover.
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Affiliation(s)
- Catherine M Bodinof Jachowski
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634, USA
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Arden Blumenthal
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, USA
| | - Andrew K Davis
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - William A Hopkins
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, USA
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3
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Sun D, Ellepola G, Herath J, Meegaskumbura M. Ecological Barriers for an Amphibian Pathogen: A Narrow Ecological Niche for Batrachochytrium salamandrivorans in an Asian Chytrid Hotspot. J Fungi (Basel) 2023; 9:911. [PMID: 37755019 PMCID: PMC10532633 DOI: 10.3390/jof9090911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023] Open
Abstract
The chytrid fungal pathogens Batrachochytrium salamandrivorans (Bsal) and B. dendrobatidis (Bd) are driving amphibian extinctions and population declines worldwide. As their origins are believed to be in East/Southeast Asia, this region is crucial for understanding their ecology. However, Bsal screening is relatively limited in this region, particularly in hotspots where Bd lineage diversity is high. To address this gap, we conducted an extensive Bsal screening involving 1101 individuals from 36 amphibian species, spanning 17 natural locations and four captive facilities in the biodiversity-rich Guangxi Zhuang Autonomous Region (GAR). Our PCR assays yielded unexpected results, revealing the complete absence of Bsal in all tested samples including 51 individuals with Bd presence. To understand the potential distribution of Bsal, we created niche models, utilizing existing occurrence records from both Asia and Europe. These models estimated potential suitable habitats for Bsal largely in the northern and southwestern parts of the GAR. Although Bsal was absent in our samples, the niche models identified 10 study sites as being potentially suitable for this pathogen. Interestingly, out of these 10 sites, Bd was detected at 8. This suggests that Bsal and Bd could possibly co-exist in these habitats, if Bsal were present. Several factors seem to influence the distribution of Bsal in Asia, including variations in temperature, local caudate species diversity, elevation, and human population density. However, it is climate-related factors that hold the greatest significance, accounting for a notable 60% contribution. The models propose that the specific climatic conditions of arid regions, primarily seen in the GAR, play a major role in the distribution of Bsal. Considering the increased pathogenicity of Bsal at stable and cooler temperatures (10-15 °C), species-dependent variations, and the potential for seasonal Bd-Bsal interactions, we emphasize the importance of periodic monitoring for Bsal within its projected range in the GAR. Our study provides deeper insights into Bsal's ecological niche and the knowledge generated will facilitate conservation efforts in amphibian populations devastated by chytrid pathogens across other regions of the world.
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Affiliation(s)
- Dan Sun
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
| | - Gajaba Ellepola
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Kandy 20400, Sri Lanka
| | - Jayampathi Herath
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- School of Biomedical Sciences, International Institute of Health Sciences (IIHS), No. 704 Negombo Road, Welisara 71722, Sri Lanka
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
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4
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Gray MJ, Carter ED, Piovia-Scott J, Cusaac JPW, Peterson AC, Whetstone RD, Hertz A, Muniz-Torres AY, Bletz MC, Woodhams DC, Romansic JM, Sutton WB, Sheley W, Pessier A, McCusker CD, Wilber MQ, Miller DL. Broad host susceptibility of North American amphibian species to Batrachochytrium salamandrivorans suggests high invasion potential and biodiversity risk. Nat Commun 2023; 14:3270. [PMID: 37277333 DOI: 10.1038/s41467-023-38979-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is a fungal pathogen of amphibians that is emerging in Europe and could be introduced to North America through international trade or other pathways. To evaluate the risk of Bsal invasion to amphibian biodiversity, we performed dose-response experiments on 35 North American species from 10 families, including larvae from five species. We discovered that Bsal caused infection in 74% and mortality in 35% of species tested. Both salamanders and frogs became infected and developed Bsal chytridiomycosis. Based on our host susceptibility results, environmental suitability conditions for Bsal, and geographic ranges of salamanders in the United States, predicted biodiversity loss is expected to be greatest in the Appalachian Region and along the West Coast. Indices of infection and disease susceptibility suggest that North American amphibian species span a spectrum of vulnerability to Bsal chytridiomycosis and most amphibian communities will include an assemblage of resistant, carrier, and amplification species. Predicted salamander losses could exceed 80 species in the United States and 140 species in North America.
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Affiliation(s)
- Matthew J Gray
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA.
| | - Edward Davis Carter
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Jonah Piovia-Scott
- School of Biological Sciences, Washington State University, Vancouver, WA, USA
| | - J Patrick W Cusaac
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Anna C Peterson
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Ross D Whetstone
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | - Andreas Hertz
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | | | - Molly C Bletz
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | - Douglas C Woodhams
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
- Smithsonian Tropical Research Institute, Ancón, Panama
| | - John M Romansic
- School of Biological Sciences, Washington State University, Vancouver, WA, USA
| | - William B Sutton
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, TN, USA
| | - Wesley Sheley
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, USA
| | - Allan Pessier
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | | | - Mark Q Wilber
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
| | - Debra L Miller
- Center for Wildlife Health, School of Natural Resources, University of Tennessee, Knoxville, TN, USA
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, USA
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5
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Davis CL, Muñoz DJ, Amburgey SM, Dinsmore CR, Teitsworth EW, Miller DAW. Multistate model to estimate sex‐specific dispersal rates and distances for a wetland‐breeding amphibian population. Ecosphere 2023. [DOI: 10.1002/ecs2.4345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Courtney L. Davis
- Department of Ecosystem Science and Management Pennsylvania State University University Park Pennsylvania USA
- Intercollege Graduate Ecology Program, Pennsylvania State University University Park Pennsylvania USA
- Cornell Lab of Ornithology Cornell University Ithaca New York USA
| | - David J. Muñoz
- Department of Ecosystem Science and Management Pennsylvania State University University Park Pennsylvania USA
- Intercollege Graduate Ecology Program, Pennsylvania State University University Park Pennsylvania USA
| | - Staci M. Amburgey
- Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
- Washington Department of Fish and Wildlife Olympia Washington USA
| | - Carli R. Dinsmore
- Department of Ecosystem Science and Management Pennsylvania State University University Park Pennsylvania USA
| | - Eric W. Teitsworth
- Department of Fisheries, Wildlife, and Conservation Biology North Carolina State University Raleigh North Carolina USA
| | - David A. W. Miller
- Department of Ecosystem Science and Management Pennsylvania State University University Park Pennsylvania USA
- Intercollege Graduate Ecology Program, Pennsylvania State University University Park Pennsylvania USA
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Schmeller DS, Cheng T, Shelton J, Lin CF, Chan-Alvarado A, Bernardo-Cravo A, Zoccarato L, Ding TS, Lin YP, Swei A, Fisher MC, Vredenburg VT, Loyau A. Environment is associated with chytrid infection and skin microbiome richness on an amphibian rich island (Taiwan). Sci Rep 2022; 12:16456. [PMID: 36180528 PMCID: PMC9525630 DOI: 10.1038/s41598-022-20547-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 09/14/2022] [Indexed: 11/09/2022] Open
Abstract
Growing evidence suggests that the origins of the panzootic amphibian pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are in Asia. In Taiwan, an island hotspot of high amphibian diversity, no amphibian mass mortality events linked to Bd or Bsal have been reported. We conducted a multi-year study across this subtropical island, sampling 2517 individuals from 30 species at 34 field sites, between 2010 and 2017, and including 171 museum samples collected between 1981 and 2009. We analyzed the skin microbiome of 153 samples (6 species) from 2017 in order to assess any association between the amphibian skin microbiome and the probability of infection amongst different host species. We did not detect Bsal in our samples, but found widespread infection by Bd across central and northern Taiwan, both taxonomically and spatially. Museum samples show that Bd has been present in Taiwan since at least 1990. Host species, geography (elevation), climatic conditions and microbial richness were all associated with the prevalence of infection. Host life-history traits, skin microbiome composition and phylogeny were associated with lower prevalence of infection for high altitude species. Overall, we observed low prevalence and burden of infection in host populations, suggesting that Bd is enzootic in Taiwan where it causes subclinical infections. While amphibian species in Taiwan are currently threatened by habitat loss, our study indicates that Bd is in an endemic equilibrium with the populations and species we investigated. However, ongoing surveillance of the infection is warranted, as changing environmental conditions may disturb the currently stable equilibrium.
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Affiliation(s)
- Dirk S. Schmeller
- grid.15781.3a0000 0001 0723 035XLaboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, INPT, UPS, Toulouse, France
| | - Tina Cheng
- grid.263091.f0000000106792318Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 USA ,grid.421477.30000 0004 0639 1575Bat Conservation International, Washington, DC USA
| | - Jennifer Shelton
- grid.7445.20000 0001 2113 8111Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG UK
| | - Chun-Fu Lin
- Zoology Division, Endemic Species Research Institute, Jiji, Nantou Taiwan, ROC
| | - Alan Chan-Alvarado
- grid.263091.f0000000106792318Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 USA
| | - Adriana Bernardo-Cravo
- grid.15781.3a0000 0001 0723 035XLaboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, INPT, UPS, Toulouse, France
| | - Luca Zoccarato
- grid.419247.d0000 0001 2108 8097Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, 16775 Stechlin, Germany
| | - Tzung-Su Ding
- grid.19188.390000 0004 0546 0241School of Forestry and Resource Conservation, National Taiwan University, Taipei City, 106 Taiwan, ROC
| | - Yu-Pin Lin
- grid.19188.390000 0004 0546 0241Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan, ROC
| | - Andrea Swei
- grid.263091.f0000000106792318Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 USA
| | - Matthew C. Fisher
- grid.7445.20000 0001 2113 8111Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG UK
| | - Vance T. Vredenburg
- grid.263091.f0000000106792318Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 USA ,grid.47840.3f0000 0001 2181 7878Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720 USA
| | - Adeline Loyau
- grid.15781.3a0000 0001 0723 035XLaboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, INPT, UPS, Toulouse, France ,grid.419247.d0000 0001 2108 8097Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, 16775 Stechlin, Germany
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Moubarak M, Fischhoff IR, Han BA, Castellanos AA. A spatially explicit risk assessment of salamander populations to
Batrachochytrium salamandrivorans
in the United States. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | | | - Barbara A. Han
- Cary Institute of Ecosystem Studies Millbrook New York USA
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8
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Wuerthner VP, Hua J, Hernández‐Gómez O. Life stage and proximity to roads shape the skin microbiota of eastern newts (Notophthalmus viridescens). Environ Microbiol 2022; 24:3954-3965. [PMID: 35355399 PMCID: PMC9790580 DOI: 10.1111/1462-2920.15986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/20/2022] [Accepted: 03/22/2022] [Indexed: 12/30/2022]
Abstract
Host-associated microbiomes play an essential role in the health of organisms, including immune system activation, metabolism and energy uptake. It is well established that microbial communities differ depending on the life stage and natural history of the organism. However, the effects of life stage and natural history on microbial communities may also be influenced by human activities. We investigated the effects of amphibian life stage (terrestrial eft vs. aquatic adult) and proximity to roadways on newt skin bacterial communities. We found that the eft and adult life stages differed in bacterial community composition; however, the effects of roads on community composition were more evident in the terrestrial eft stage compared to the aquatic adult stage. Terrestrial efts sampled close to roads possessed richer communities than those living further away from the influence of roads. When accounting for amplicon sequence variants with predicted antifungal capabilities, in the adult life stage, we observed a decrease in anti-fungal bacteria with distance to roads. In contrast, in the eft stage, we found an increase in anti-fungal bacteria with distance to roads. Our results highlight the need to consider the effects of human activities when evaluating how host-associated microbiomes differ across life stages of wildlife.
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Affiliation(s)
| | - Jessica Hua
- Department of Biological SciencesBinghamton UniversityBinghamtonNY,Department of Forest and Wildlife EcologyUniversity of Wisconsin‐MadisonMadisonWI
| | - Obed Hernández‐Gómez
- Department of Environmental Sciences, Policy, and ManagementUniversity of California‐BerkeleyBerkeleyCA,Department of Natural Sciences and MathematicsDominican University of CaliforniaSan RafaelCA
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Inhibitory Bacterial Diversity and Mucosome Function Differentiate Susceptibility of Appalachian Salamanders to Chytrid Fungal Infection. Appl Environ Microbiol 2022; 88:e0181821. [PMID: 35348389 PMCID: PMC9040618 DOI: 10.1128/aem.01818-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mucosal defenses are crucial in animals for protection against pathogens and predators. Host defense peptides (antimicrobial peptides, AMPs) as well as skin-associated microbes are key components of mucosal immunity, particularly in amphibians. We integrate microbiology, molecular biology, network-thinking, and proteomics to understand how host and microbially derived products on amphibian skin (referred to as the mucosome) serve as pathogen defenses. We studied defense mechanisms against chytrid pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), in four salamander species with different Batrachochytrium susceptibilities. Bd infection was quantified using qPCR, mucosome function (i.e., ability to kill Bd or Bsal zoospores in vitro), skin bacterial communities using 16S rRNA gene amplicon sequencing, and the role of Bd-inhibitory bacteria in microbial networks across all species. We explored the presence of candidate-AMPs in eastern newts and red-backed salamanders. Eastern newts had the highest Bd prevalence and mucosome function, while red-back salamanders had the lowest Bd prevalence and mucosome function, and two-lined salamanders and seal salamanders were intermediates. Salamanders with highest Bd infection intensity showed greater mucosome function. Bd infection prevalence significantly decreased as putative Bd-inhibitory bacterial richness and relative abundance increased on hosts. In co-occurrence networks, some putative Bd-inhibitory bacteria were found as hub-taxa, with red-backs having the highest proportion of protective hubs and positive associations related to putative Bd-inhibitory hub bacteria. We found more AMP candidates on salamanders with lower Bd susceptibility. These findings suggest that salamanders possess distinct innate mechanisms that affect chytrid fungi. IMPORTANCE How host mucosal defenses interact, and influence disease outcome is critical in understanding host defenses against pathogens. A more detailed understanding is needed of the interactions between the host and the functioning of its mucosal defenses in pathogen defense. This study investigates the variability of chytrid susceptibility in salamanders and the innate defenses each species possesses to mediate pathogens, thus advancing the knowledge toward a deeper understanding of the microbial ecology of skin-associated bacteria and contributing to the development of bioaugmentation strategies to mediate pathogen infection and disease. This study improves the understanding of complex immune defense mechanisms in salamanders and highlights the potential role of the mucosome to reduce the probability of Bd disease development and that putative protective bacteria may reduce likelihood of Bd infecting skin.
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10
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Sheley WC, Gray MJ, Wilber MQ, Cray C, Carter ED, Miller DL. Electrolyte imbalances and dehydration play a key role in Batrachochytrium salamandrivorans chytridiomycosis. Front Vet Sci 2022; 9:1055153. [PMID: 36713878 PMCID: PMC9880075 DOI: 10.3389/fvets.2022.1055153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/28/2022] [Indexed: 01/15/2023] Open
Abstract
Introduction One of the most important emerging infectious diseases of amphibians is caused by the fungal pathogen Batrachochytrium salamandrivorans (Bsal). Bsal was recently discovered and is of global concern due to its potential to cause high mortality in amphibians, especially salamander species. To date, little has been reported on the pathophysiological effects of Bsal; however, studies of a similar fungus, B. dendrobatidis (Bd), have shown that electrolyte losses and immunosuppression likely play a key role in morbidity and mortality associated with this disease. The goal of this study was to investigate pathophysiological effects and immune responses associated with Bsal chytridiomycosis using 49 rough-skinned newts (Taricha granulosa) as the model species. Methods Taricha granulosa were exposed to a 1 × 107 per 10 mL dose of Bsal zoospores and allowed to reach various stages of disease progression before being humanely euthanized. At the time of euthanasia, blood was collected for biochemical and hematological analyses as well as protein electrophoresis. Ten standardized body sections were histologically examined, and Bsal-induced skin lesions were counted and graded on a scale of 1-5 based on severity. Results Results indicated that electrolyte imbalances and dehydration induced by damage to the epidermis likely play a major role in the pathogenesis of Bsal chytridiomycosis in this species. Additionally, Bsal-infected, clinically diseased T. granulosa exhibited a systemic inflammatory response identified through alterations in complete blood counts and protein electrophoretograms. Discussion Overall, these results provide foundational information on the pathogenesis of this disease and highlight the differences and similarities between Bsal and Bd chytridiomycosis.
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Affiliation(s)
- Wesley C. Sheley
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- *Correspondence: Wesley C. Sheley
| | - Matthew J. Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Mark Q. Wilber
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Carolyn Cray
- Division of Comparative Pathology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - E. Davis Carter
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Debra L. Miller
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
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11
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Cowgill M, Zink AG, Sparagon W, Yap TA, Sulaeman H, Koo MS, Vredenburg VT. Social Behavior, Community Composition, Pathogen Strain, and Host Symbionts Influence Fungal Disease Dynamics in Salamanders. Front Vet Sci 2021; 8:742288. [PMID: 34938792 PMCID: PMC8687744 DOI: 10.3389/fvets.2021.742288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022] Open
Abstract
The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), which can cause a fatal disease called chytridiomycosis, is implicated in the collapse of hundreds of host amphibian species. We describe chytridiomycosis dynamics in two co-occurring terrestrial salamander species, the Santa Lucia Mountains slender salamander, Batrachoseps luciae, and the arboreal salamander, Aneides lugubris. We (1) conduct a retrospective Bd-infection survey of specimens collected over the last century, (2) estimate present-day Bd infections in wild populations, (3) use generalized linear models (GLM) to identify biotic and abiotic correlates of infection risk, (4) investigate susceptibility of hosts exposed to Bd in laboratory trials, and (5) examine the ability of host skin bacteria to inhibit Bd in culture. Our historical survey of 2,866 specimens revealed that for most of the early 20th century (~1920–1969), Bd was not detected in either species. By the 1990s the proportion of infected specimens was 29 and 17% (B. luciae and A. lugubris, respectively), and in the 2010s it was 10 and 17%. This was similar to the number of infected samples from contemporary populations (2014–2015) at 10 and 18%. We found that both hosts experience signs of chytridiomycosis and suffered high Bd-caused mortality (88 and 71% for B. luciae and A. lugubris, respectively). Our GLM revealed that Bd-infection probability was positively correlated with intraspecific group size and proximity to heterospecifics but not to abiotic factors such as precipitation, minimum temperature, maximum temperature, mean temperature, and elevation, or to the size of the hosts. Finally, we found that both host species contain symbiotic skin-bacteria that inhibit growth of Bd in laboratory trials. Our results provide new evidence consistent with other studies showing a relatively recent Bd invasion of amphibian host populations in western North America and suggest that the spread of the pathogen may be enabled both through conspecific and heterospecific host interactions. Our results suggest that wildlife disease studies should assess host-pathogen dynamics that consider the interactions and effects of multiple hosts, as well as the historical context of pathogen invasion, establishment, and epizootic to enzootic transitions to better understand and predict disease dynamics.
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Affiliation(s)
- Mae Cowgill
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Andrew G Zink
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Wesley Sparagon
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography and Sea Grant College Program, UUniversity of Hawai'i at Mānoa, HI, United States
| | - Tiffany A Yap
- Center for Biological Diversity, Oakland, CA, United States
| | - Hasan Sulaeman
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Michelle S Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, United States.,Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
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12
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Buttimer S, Hernández-Gómez O, Rosenblum EB. Skin bacterial metacommunities of San Francisco Bay Area salamanders are structured by host genus and habitat quality. FEMS Microbiol Ecol 2021; 97:6464136. [PMID: 34918086 DOI: 10.1093/femsec/fiab162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Host-associated microbial communities can influence physiological processes of macroorganisms, including contributing to infectious disease resistance. For instance, some bacteria that live on amphibian skin produce antifungal compounds that inhibit two lethal fungal pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Therefore, differences in microbiome composition among host species or populations within a species can contribute to variation in susceptibility to Bd/Bsal. This study applies 16S rRNA sequencing to characterize the skin bacterial microbiomes of three widespread terrestrial salamander genera native to the western United States. Using a metacommunity structure analysis, we identified dispersal barriers for these influential bacteria between salamander families and localities. We also analyzed the effects of habitat characteristics such as percent natural cover and temperature seasonality on the microbiome. We found that certain environmental variables may influence the skin microbial communities of some salamander genera more strongly than others. Each salamander family had a somewhat distinct community of putative anti-Bd skin bacteria, suggesting that salamanders may select for a functional assembly of cutaneous symbionts that could differ in its ability to protect these amphibians from disease. Our observations raise the need to consider host identity and environmental heterogeneity during the selection of probiotics to treat wildlife diseases.
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Affiliation(s)
- Shannon Buttimer
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A.,Department of Biological Sciences - The University of Alabama, Tuscaloosa, AL, U.S.A
| | - Obed Hernández-Gómez
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A.,School of Health and Natural Sciences - Dominican University of California, San Rafael, CA, U.S.A
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A
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13
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García‐Rodríguez A, Basanta MD, García‐Castillo MG, Zumbado‐Ulate H, Neam K, Rovito S, Searle CL, Parra‐Olea G. Anticipating the potential impacts of
Batrachochytrium salamandrivorans
on Neotropical salamander diversity. Biotropica 2021. [DOI: 10.1111/btp.13042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Adrián García‐Rodríguez
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- BioInvasions, Global Change, Macroecology‐Group Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - M. Delia Basanta
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- Centro de Ciencias Genómicas Universidad Nacional Autónoma de México Cuernavaca Morelos México
| | - Mirna G. García‐Castillo
- Universidad Politécnica de Huatusco Huatusco Veracruz México
- Facultad de Ciencias Biológicas y Agropecuarias Región: Orizaba–Córdoba Universidad Veracruzana Amatlán de los Reyes Veracruz México
| | | | - Kelsey Neam
- Global Wildlife Conservation Austin Texas USA
- Amphibian Specialist Group IUCN Species Survival Commission USA
| | - Sean Rovito
- Unidad de Genómica Avanzada (Langebio) CINVESTAV Irapuato México
| | - Catherine L. Searle
- Department of Biological Sciences Purdue University West Lafayette Indiana USA
| | - Gabriela Parra‐Olea
- Departamento de Zoología Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México México
- Amphibian Specialist Group IUCN Species Survival Commission USA
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14
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Koo MS, Vredenburg VT, Deck JB, Olson DH, Ronnenberg KL, Wake DB. Tracking, Synthesizing, and Sharing Global Batrachochytrium Data at AmphibianDisease.org. Front Vet Sci 2021; 8:728232. [PMID: 34692807 PMCID: PMC8527349 DOI: 10.3389/fvets.2021.728232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Emerging infectious diseases have been especially devastating to amphibians, the most endangered class of vertebrates. For amphibians, the greatest disease threat is chytridiomycosis, caused by one of two chytridiomycete fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Research over the last two decades has shown that susceptibility to this disease varies greatly with respect to a suite of host and pathogen factors such as phylogeny, geography (including abiotic factors), host community composition, and historical exposure to pathogens; yet, despite a growing body of research, a comprehensive understanding of global chytridiomycosis incidence remains elusive. In a large collaborative effort, Bd-Maps was launched in 2007 to increase multidisciplinary investigations and understanding using compiled global Bd occurrence data (Bsal was not discovered until 2013). As its database functions aged and became unsustainable, we sought to address critical needs utilizing new technologies to meet the challenges of aggregating data to facilitate research on both Bd and Bsal. Here, we introduce an advanced central online repository to archive, aggregate, and share Bd and Bsal data collected from around the world. The Amphibian Disease Portal (https://amphibiandisease.org) addresses several critical community needs while also helping to build basic biological knowledge of chytridiomycosis. This portal could be useful for other amphibian diseases and could also be replicated for uses with other wildlife diseases. We show how the Amphibian Disease Portal provides: (1) a new repository for the legacy Bd-Maps data; (2) a repository for sample-level data to archive datasets and host published data with permanent DOIs; (3) a flexible framework to adapt to advances in field, laboratory, and informatics technologies; and (4) a global aggregation of Bd and Bsal infection data to enable and accelerate research and conservation. The new framework for this project is built using biodiversity informatics best practices and metadata standards to ensure scientific reproducibility and linkages across other biological and biodiversity repositories.
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Affiliation(s)
- Michelle S Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
| | - Vance T Vredenburg
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States.,Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - John B Deck
- Berkeley Natural History Museums, University of California, Berkeley, Berkeley, CA, United States
| | - Deanna H Olson
- US Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, OR, United States
| | - Kathryn L Ronnenberg
- US Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, OR, United States
| | - David B Wake
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
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15
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Vasconcelos IAD, Souza JOD, de Castro JS, Santana CJCD, Magalhães ACM, Castro MDS, Pires Júnior OR. Salamanders and caecilians, neglected from the chemical point of view. TOXIN REV 2021. [DOI: 10.1080/15569543.2021.1977326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | | | | | - Carlos José Correia de Santana
- Department of Physiological Sciences, University of Brasilia, Brasilia, Brazil
- Department of Cell Biology, University of Brasilia, Brasilia, Brazil
| | | | - Mariana de Souza Castro
- Department of Physiological Sciences, University of Brasilia, Brasilia, Brazil
- Department of Cell Biology, University of Brasilia, Brasilia, Brazil
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16
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Eskew EA, Fraser D, Vonhof MJ, Pinsky ML, Maslo B. Host gene expression in wildlife disease: making sense of species-level responses. Mol Ecol 2021; 30:6517-6530. [PMID: 34516689 DOI: 10.1111/mec.16172] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 08/16/2021] [Accepted: 08/31/2021] [Indexed: 12/11/2022]
Abstract
Emerging infectious diseases are significant threats to wildlife conservation, yet the impacts of pathogen exposure and infection can vary widely among host species. As such, conservation biologists and disease ecologists have increasingly aimed to understand species-specific host susceptibility using molecular methods. In particular, comparative gene expression assays have been used to contrast the transcriptomic responses of disease-resistant and disease-susceptible hosts to pathogen exposure. This work usually assumes that the gene expression responses of disease-resistant species will reveal the activation of molecular pathways contributing to host defence. However, results often show that disease-resistant hosts undergo little gene expression change following pathogen challenge. Here, we discuss the mechanistic implications of these "null" findings and offer methodological suggestions for future molecular studies of wildlife disease. First, we highlight that muted transcriptomic responses with minimal immune system recruitment may indeed be protective for nonsusceptible hosts if they limit immunopathology and promote pathogen tolerance in systems where susceptible hosts suffer from genetic dysregulation. Second, we argue that overly narrow investigation of responses to pathogen exposure may overlook important, constitutively active molecular pathways that underlie species-specific defences. Finally, we outline alternative study designs and approaches that complement interspecific transcriptomic comparisons, including intraspecific gene expression studies and genomic methods to detect signatures of selection. Collectively, these insights will help ecologists extract maximal information from conservation-relevant transcriptomic data sets, leading to a deeper understanding of host defences and, ultimately, the implementation of successful conservation interventions.
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Affiliation(s)
- Evan A Eskew
- Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.,Department of Biology, Pacific Lutheran University, Tacoma, Washington, USA
| | - Devaughn Fraser
- Wildlife Genetics Research Laboratory, California Department of Fish and Wildlife, Sacramento, California, USA
| | - Maarten J Vonhof
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
| | - Malin L Pinsky
- Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Brooke Maslo
- Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
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17
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Hughes AC, Marshall BM, Strine C. Gaps in global wildlife trade monitoring leave amphibians vulnerable. eLife 2021; 10:70086. [PMID: 34382939 PMCID: PMC8425949 DOI: 10.7554/elife.70086] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/11/2021] [Indexed: 11/21/2022] Open
Abstract
As the biodiversity crisis continues, we must redouble efforts to understand and curb pressures pushing species closer to extinction. One major driver is the unsustainable trade of wildlife. Trade in internationally regulated species gains the most research attention, but this only accounts for a minority of traded species and we risk failing to appreciate the scale and impacts of unregulated legal trade. Despite being legal, trade puts pressure on wild species via direct collection, introduced pathogens, and invasive species. Smaller species-rich vertebrates, such as reptiles, fish, and amphibians, may be particularly vulnerable to trading because of gaps in regulations, small distributions, and demand of novel species. Here, we combine data from five sources: online web searches in six languages, Convention on International Trade in Endangered Species (CITES) trade database, Law Enforcement Management Information System (LEMIS) trade inventory, IUCN assessments, and a recent literature review, to characterise the global trade in amphibians, and also map use by purpose including meat, pets, medicinal, and for research. We show that 1215 species are being traded (17% of amphibian species), almost three times previous recorded numbers, 345 are threatened, and 100 Data Deficient or unassessed. Traded species origin hotspots include South America, China, and Central Africa; sources indicate 42% of amphibians are taken from the wild. Newly described species can be rapidly traded (mean time lag of 6.5 years), including threatened and unassessed species. The scale and limited regulation of the amphibian trade, paired with the triptych of connected pressures (collection, pathogens, invasive species), warrants a re-examination of the wildlife trade status quo, application of the precautionary principle in regard to wildlife trade, and a renewed push to achieve global biodiversity goals. In the last few decades, exotic pets have become much more common. In the UK in 2008, reptiles and amphibians were more popular than dogs, with over eight million in captivity. But while almost all pet cats and dogs are born and bred in captivity, exotic pets are often taken from the wild, putting species and their habitats at risk. An international trade agreement called the Convention on International Trade in Endangered Species (CITES) strives to prevent unsustainable animal trade. But to get CITES protection, species depend on data showing that wildlife trade threatens their survival. In addition, their range countries need to first propose them to be listed. For most wild animal species, there are no data on population size or population decline. In the case of amphibians, CITES regulates the trade of just 2.5% of species. This leaves the rest with no protection from overarching international trade regulations. To protect these animals, researchers need to find out which species are in trade, where they are coming from, and how many are already threatened. To address this, Hughes, Marshall and Strine combined data from five sources, including official CITES trade records, recent research and an online search for amphibian sales in six languages. The data showed evidence of trade in at least 1,215 amphibian species, representing 17% of all amphibians. The figure is three times higher than previous estimates. Of the species in trade, more than one in five is vulnerable to extinction, endangered, or critically endangered. For a further 100 of the traded species, data on population were unavailable. Moreover, analysis of the origins of traded individuals showed that around 42% came from the wild. Tropical parts of the world had the highest number of species in trade, but the data showed exchanges happening across the globe. Unsustainable wildlife trade can have devastating consequences for wild animals. It has already driven at least 21 reptile species to extinction, and data of amphibian species are unknown. To prevent further species going extinct, legal wildlife trade should follow the precautionary principle when it comes to wildlife trade. Rather than allowing people to trade a species until CITES regulates it, a blanket ban should come into force for species that have not been assessed or are threatened. Trade would be able to resume for a species only when assessments show that it would not cause major population decline, or secure, captive breeding facilities can be guaranteed.
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Affiliation(s)
- Alice C Hughes
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Benjamin Michael Marshall
- Institute of Science, School of Biology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Colin Strine
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand, Nakhon Ratchasima, Thailand
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18
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Beukema W, Erens J, Schulz V, Stegen G, Spitzen-van der Sluijs A, Stark T, Laudelout A, Kinet T, Kirschey T, Poulain M, Miaud C, Steinfartz S, Martel A, Pasmans F. Landscape epidemiology of Batrachochytrium salamandrivorans: reconciling data limitations and conservation urgency. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02342. [PMID: 33817953 DOI: 10.1002/eap.2342] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/01/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Starting in 2010, rapid fire salamander (Salamandra salamandra) population declines in northwestern Europe heralded the emergence of Batrachochytrium salamandrivorans (Bsal), a salamander-pathogenic chytrid fungus. Bsal poses an imminent threat to global salamander diversity owing to its wide host range, high pathogenicity, and long-term persistence in ecosystems. While there is a pressing need to develop further research and conservation actions, data limitations inherent to recent pathogen emergence obscure necessary insights into Bsal disease ecology. Here, we use a hierarchical modeling framework to describe Bsal landscape epidemiology of outbreak sites in light of these methodological challenges. Using model selection and machine learning, we find that Bsal presence is associated with humid and relatively cool, stable climates. Outbreaks are generally located in areas characterized by low landscape heterogeneity and low steepness of slope. We further find an association between Bsal presence and high trail density, suggesting that human-mediated spread may increase risk for spillover between populations. We then use distribution modeling to show that favorable conditions occur in lowlands influenced by the North Sea, where increased survey effort is needed to determine how Bsal impacts local newt populations, but also in hill- and mountain ranges in northeastern France and the lower half of Germany. Finally, connectivity analyses suggest that these hill- and mountain ranges may act as stepping stones for further spread southward. Our results provide initial insight into regional environmental conditions underlying Bsal epizootics, present updated invasibility predictions for northwestern Europe, and lead us to discuss a wide variety of potential survey and research actions needed to advance future conservation and mitigation efforts.
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Affiliation(s)
- Wouter Beukema
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Jesse Erens
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Vanessa Schulz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
- Technische Universität Braunschweig, Division of Evolutionary Biology, Zoological Institute, Mendelssohnstrasse 4, Braunschweig, 38106, Germany
| | - Gwij Stegen
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | | | - Tariq Stark
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Arnaud Laudelout
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Thierry Kinet
- Natagora, Traverse des Muses 1, Namur, 5000, Belgium
| | - Tom Kirschey
- Nature and Biodiversity Conservation Union (NABU), Charitéstrasse 3, Berlin, 10117, Germany
| | - Marie Poulain
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Claude Miaud
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Sebastian Steinfartz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
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19
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Bernard RF, Grant EHC. Rapid Assessment Indicates Context‐Dependent Mitigation for Amphibian Disease Risk. WILDLIFE SOC B 2021. [DOI: 10.1002/wsb.1198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Riley F. Bernard
- Department of Zoology and Physiology University of Wyoming Laramie WY 82071 USA
| | - Evan H. Campbell Grant
- United States Geological Survey, Eastern Ecological Science Center S. O. Conte Anadromous Fish Laboratory Turners Falls MA 01376 USA
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20
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Plethodontid salamanders show variable disease dynamics in response to Batrachochytrium salamandrivorans chytridiomycosis. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02536-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Tompros A, Dean AD, Fenton A, Wilber MQ, Carter ED, Gray MJ. Frequency-dependent transmission of Batrachochytrium salamandrivorans in eastern newts. Transbound Emerg Dis 2021; 69:731-741. [PMID: 33617686 PMCID: PMC9290712 DOI: 10.1111/tbed.14043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/11/2021] [Accepted: 02/19/2021] [Indexed: 12/25/2022]
Abstract
Transmission is the fundamental process whereby pathogens infect their hosts and spread through populations, and can be characterized using mathematical functions. The functional form of transmission for emerging pathogens can determine pathogen impacts on host populations and can inform the efficacy of disease management strategies. By directly measuring transmission between infected and susceptible adult eastern newts (Notophthalmus viridescens) in aquatic mesocosms, we identified the most plausible transmission function for the emerging amphibian fungal pathogen Batrachochytrium salamandrivorans (Bsal). Although we considered a range of possible transmission functions, we found that Bsal transmission was best explained by pure frequency dependence. We observed that >90% of susceptible newts became infected within 17 days post‐exposure to an infected newt across a range of host densities and initial infection prevalence treatments. Under these conditions, we estimated R0 = 4.9 for Bsal in an eastern newt population. Our results suggest that Bsal has the capability of driving eastern newt populations to extinction and that managing host density may not be an effective management strategy. Intervention strategies that prevent Bsal introduction or increase host resistance or tolerance to infection may be more effective. Our results add to the growing empirical evidence that transmission of wildlife pathogens can saturate and be functionally frequency‐dependent.
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Affiliation(s)
- Adrianna Tompros
- Center for Wildlife Health, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Andrew D Dean
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Andy Fenton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Mark Q Wilber
- Center for Wildlife Health, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, USA.,Department of Ecology, Evolution and Marine Biology, University of California-Santa Barbara, Santa Barbara, CA, USA
| | - Edward Davis Carter
- Center for Wildlife Health, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Matthew J Gray
- Center for Wildlife Health, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
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22
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Winter is coming-Temperature affects immune defenses and susceptibility to Batrachochytrium salamandrivorans. PLoS Pathog 2021; 17:e1009234. [PMID: 33600433 PMCID: PMC7891748 DOI: 10.1371/journal.ppat.1009234] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022] Open
Abstract
Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14°C than at 6 and 22°C. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent susceptibility results, we performed a geographic analysis that revealed N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion, which shifted risk north compared to previous assessments. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable disease management strategy. In 2010, a new skin-eating fungus, Batrachochytrium salamandrivorans (Bsal), was discovered killing salamanders in the Netherlands. Since then, the pathogen has spread to other European countries. Bsal is believed to be from Asia and is being translocated through the international trade of amphibians. To our knowledge, Bsal has not arrived to North America. As a proactive strategy for disease control, we evaluated how a range of environmental temperatures in North America could affect invasion risk of Bsal into a widely distributed salamander species, the eastern newt (Notophthalmus viridescens). Our results show that northeastern USA, southeastern Canada, and the higher elevations of the Appalachian Mountains have the greatest likelihood of Bsal invasion, when temperature-dependent susceptibility is included in risk analyses. Changes in eastern newt susceptibility to Bsal infection associated with temperature are likely an interaction between pathogen replication rate and host immune defenses, including changes in skin microbiome composition and the host’s ability to produce Bsal-killing proteins on the skin. Our study provides new insights into how latitude, elevation and season can impact the epidemiology of Bsal, and suggests that strategies that manipulate microclimate of newt habitats could be useful in managing Bsal outbreaks and that climate change will impact Bsal invasion probability.
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23
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Wilber MQ, Carter ED, Gray MJ, Briggs CJ. Putative resistance and tolerance mechanisms have little impact on disease progression for an emerging salamander pathogen. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Mark Q. Wilber
- Department of Ecology Evolution and Marine Biology University of California Santa Barbara CA USA
- Center for Wildlife Health Department of Forestry, Wildlife and Fisheries University of Tennessee Institute of Agriculture Knoxville TN USA
| | - Edward Davis Carter
- Center for Wildlife Health Department of Forestry, Wildlife and Fisheries University of Tennessee Institute of Agriculture Knoxville TN USA
| | - Matthew J. Gray
- Center for Wildlife Health Department of Forestry, Wildlife and Fisheries University of Tennessee Institute of Agriculture Knoxville TN USA
| | - Cheryl J. Briggs
- Department of Ecology Evolution and Marine Biology University of California Santa Barbara CA USA
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24
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Pereira KE, Woodley SK. Skin defenses of North American salamanders against a deadly salamander fungus. Anim Conserv 2021. [DOI: 10.1111/acv.12666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- K. E. Pereira
- Department of Biological Sciences Duquesne University Pittsburgh PA USA
| | - S. K. Woodley
- Department of Biological Sciences Duquesne University Pittsburgh PA USA
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25
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Islam MR, Gray MJ, Peace A. Identifying the Dominant Transmission Pathway in a Multi-stage Infection Model of the Emerging Fungal Pathogen Batrachochytrium Salamandrivorans on the Eastern Newt. INFECTIOUS DISEASES AND OUR PLANET 2021. [DOI: 10.1007/978-3-030-50826-5_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Bioaccumulation of the pesticide imidacloprid in stream organisms and sublethal effects on salamanders. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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27
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Abstract
This article updates the understanding of two extirpation-driving infectious diseases, Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, and Ranavirus. Experimental studies and dynamic, multifactorial population modeling have outlined the epidemiology and future population impacts of B dendrobatidis, B salamandrivorans, and Ranavirus. New genomic findings on divergent fungal and viral pathogens can help optimize control and disease management strategies. Although there have been major advances in knowledge of amphibian pathogens, controlled studies are needed to guide population recovery to elucidate and evaluate transmission routes for several pathogens, examine environmental control, and validate new diagnostic tools to confirm the presence of disease.
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Swafford AJM, Hussey SP, Fritz-Laylin LK. High-efficiency electroporation of chytrid fungi. Sci Rep 2020; 10:15145. [PMID: 32934254 PMCID: PMC7493940 DOI: 10.1038/s41598-020-71618-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/19/2020] [Indexed: 11/09/2022] Open
Abstract
Two species of parasitic fungi from the phylum Chytridiomycota (chytrids) are annihilating global amphibian populations. These chytrid species-Batrachochytrium dendrobatidis and B. salamandrivorans-have high rates of mortality and transmission. Upon establishing infection in amphibians, chytrids rapidly multiply within the skin and disrupt their hosts' vital homeostasis mechanisms. Current disease models suggest that chytrid fungi locate and infect their hosts during a motile, unicellular 'zoospore' life stage. Moreover, other chytrid species parasitize organisms from across the tree of life, making future epidemics in new hosts a likely possibility. Efforts to mitigate the damage and spread of chytrid disease have been stymied by the lack of knowledge about basic chytrid biology and tools with which to test molecular hypotheses about disease mechanisms. To overcome this bottleneck, we have developed high-efficiency delivery of molecular payloads into chytrid zoospores using electroporation. Our electroporation protocols result in payload delivery to between 75 and 97% of living cells of three species: B. dendrobatidis, B. salamandrivorans, and a non-pathogenic relative, Spizellomyces punctatus. This method lays the foundation for molecular genetic tools needed to establish ecological mitigation strategies and answer broader questions in evolutionary and cell biology.
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Affiliation(s)
- Andrew J M Swafford
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Shane P Hussey
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Lillian K Fritz-Laylin
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, 01003, USA.
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29
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Kumar R, Malagon DA, Carter ED, Miller DL, Bohanon ML, Cusaac JPW, Peterson AC, Gray MJ. Experimental methodologies can affect pathogenicity of Batrachochytrium salamandrivorans infections. PLoS One 2020; 15:e0235370. [PMID: 32915779 PMCID: PMC7485798 DOI: 10.1371/journal.pone.0235370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Controlled experiments are one approach to understanding the pathogenicity of etiologic agents to susceptible hosts. The recently discovered fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has resulted in a surge of experimental investigations because of its potential to impact global salamander biodiversity. However, variation in experimental methodologies could thwart knowledge advancement by introducing confounding factors that make comparisons difficult among studies. Thus, our objective was to evaluate if variation in experimental methods changed inferences made on the pathogenicity of Bsal. We tested whether passage duration of Bsal culture, exposure method of the host to Bsal (water bath vs. skin inoculation), Bsal culturing method (liquid vs. plated), host husbandry conditions (aquatic vs. terrestrial), and skin swabbing frequency influenced diseased-induced mortality in a susceptible host species, the eastern newt (Notophthalmus viridescens). We found that disease-induced mortality was faster for eastern newts when exposed to a low passage isolate, when newts were housed in terrestrial environments, and if exposure to zoospores occurred via water bath. We did not detect differences in disease-induced mortality between culturing methods or swabbing frequencies. Our results illustrate the need to standardize methods among Bsal experiments. We provide suggestions for future Bsal experiments in the context of hypothesis testing and discuss the ecological implications of our results.
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Affiliation(s)
- Rajeev Kumar
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Daniel A. Malagon
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Edward Davis Carter
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Debra L. Miller
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Markese L. Bohanon
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Joseph Patrick W. Cusaac
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Anna C. Peterson
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Matthew J. Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
- * E-mail:
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30
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Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians. Sci Rep 2020; 10:13012. [PMID: 32747670 PMCID: PMC7400573 DOI: 10.1038/s41598-020-69486-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 05/22/2020] [Indexed: 11/22/2022] Open
Abstract
The salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in Europe. The potential for spread via international trade into North America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the landscape, low prevalence at a site, and imperfect detection of the diagnostic tests. We implemented a large-scale survey to determine if Bsal was present in North America designed to target taxa and localities where Bsal was determined highest risk to be present based on species susceptibility and geography. Our analysis included a Bayesian model to estimate the probability of occurrence of Bsal given our prior knowledge of the occurrence and prevalence of the pathogen. We failed to detect Bsal in any of 11,189 samples from 594 sites in 223 counties within 35 U.S. states and one site in Mexico. Our modeling indicates that Bsal is highly unlikely to occur within wild amphibians in the U.S. and suggests that the best proactive response is to continue mitigation efforts against the introduction and establishment of the disease and to develop plans to reduce impacts should Bsal establish.
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31
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Rollins-Smith LA. Global Amphibian Declines, Disease, and the Ongoing Battle between Batrachochytrium Fungi and the Immune System. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.178] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Louise A. Rollins-Smith
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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32
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Zellmer AJ, Slezak P, Katz TS. Clearing up the Crystal Ball: Understanding Uncertainty in Future Climate Suitability Projections for Amphibians. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Amanda J. Zellmer
- Department of Biology, Occidental College, 1600 Campus Road, Los Angeles, CA 90041, USA
| | - Pavlina Slezak
- Department of Biology, Occidental College, 1600 Campus Road, Los Angeles, CA 90041, USA
| | - Tatum S. Katz
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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33
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McDonald CA, Longo AV, Lips KR, Zamudio KR. Incapacitating effects of fungal coinfection in a novel pathogen system. Mol Ecol 2020; 29:3173-3186. [PMID: 32310322 DOI: 10.1111/mec.15452] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/16/2020] [Accepted: 04/08/2020] [Indexed: 12/20/2022]
Abstract
As globalization lowers geographic barriers to movement, coinfection with novel and enzootic pathogens is increasingly likely. Novel and enzootic pathogens can interact synergistically or antagonistically, leading to increased or decreased disease severity. Here we examine host immune responses to coinfection with two closely related fungal pathogens: Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Both pathogens have had detrimental effects on amphibian populations, with Bd now largely enzootic, while Bsal is currently spreading and causing epizootics. Recent experimental work revealed that newts coinfected with Bd and Bsal had significantly higher mortality than those infected with either pathogen alone. Here we characterize host immunogenomic responses to chytrid coinfection relative to single infection. Across several classes of immune genes including pattern recognition receptors, cytokines, and MHC, coinfected host gene expression was weakly upregulated or comparable to that seen in single Bd infection, but significantly decreased when compared to Bsal infection. Combined with strong complement pathway downregulation and keratin upregulation, these results indicate that coinfection with Bd and Bsal compromises immune responses active against Bsal alone. As Bsal continues to invade naïve habitats where Bd is enzootic, coinfection will be increasingly common. If other Bd-susceptible species in the region have similar responses, interactions between the two pathogens could cause severe population and community-level declines.
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Affiliation(s)
- Cait A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Ana V Longo
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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35
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Malagon DA, Melara LA, Prosper OF, Lenhart S, Carter ED, Fordyce JA, Peterson AC, Miller DL, Gray MJ. Host density and habitat structure influence host contact rates and Batrachochytrium salamandrivorans transmission. Sci Rep 2020; 10:5584. [PMID: 32221329 PMCID: PMC7101388 DOI: 10.1038/s41598-020-62351-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 03/11/2020] [Indexed: 12/22/2022] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is an emerging invasive pathogen that is highly pathogenic to salamander species. Modeling infection dynamics in this system can facilitate proactive efforts to mitigate this pathogen's impact on North American species. Given its widespread distribution and high abundance, the eastern newt (Notophthalmus viridescens) has the potential to significantly influence Bsal epidemiology. We designed experiments to 1) estimate contact rates given different host densities and habitat structure and 2) estimate the probability of transmission from infected to susceptible individuals. Using parameter estimates from data generated during these experiments, we modeled infection and disease outcomes for a population of newts using a system of differential equations. We found that host contact rates were density-dependent, and that adding habitat structure reduced contacts. The probability of Bsal transmission given contact between newts was very high (>90%) even at early stages of infection. Our simulations show rapid transmission of Bsal among individuals following pathogen introduction, with infection prevalence exceeding 90% within one month and >80% mortality of newts in three months. Estimates of basic reproductive rate (R0) of Bsal for eastern newts were 1.9 and 3.2 for complex and simple habitats, respectively. Although reducing host density and increasing habitat complexity might decrease transmission, these management strategies may be ineffective at stopping Bsal invasion in eastern newt populations due to this species’ hyper-susceptibility.
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Affiliation(s)
- Daniel A Malagon
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Luis A Melara
- Department of Mathematics, Shippensburg University, Shippensburg, PA, 17257, USA
| | - Olivia F Prosper
- Department of Mathematics, University of Kentucky, Lexington, KY, 40506, USA.,Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Edward Davis Carter
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - J A Fordyce
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Anna C Peterson
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Debra L Miller
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.,Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, 37996, USA
| | - Matthew J Gray
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.
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36
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Martel A, Vila‐Escale M, Fernández‐Giberteau D, Martinez‐Silvestre A, Canessa S, Van Praet S, Pannon P, Chiers K, Ferran A, Kelly M, Picart M, Piulats D, Li Z, Pagone V, Pérez‐Sorribes L, Molina C, Tarragó‐Guarro A, Velarde‐Nieto R, Carbonell F, Obon E, Martínez‐Martínez D, Guinart D, Casanovas R, Carranza S, Pasmans F. Integral chain management of wildlife diseases. Conserv Lett 2020. [DOI: 10.1111/conl.12707] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- An Martel
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Mireia Vila‐Escale
- Oficina Tècnica de Parcs Naturals. Diputació de Barcelona Barcelona Spain
| | - Daniel Fernández‐Giberteau
- Grup de Recerca de l'Escola de la Natura de Parets del Vallès – Ajuntament de Parets del Vallès Parets del Vallès Spain
| | | | - Stefano Canessa
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Sarah Van Praet
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Pep Pannon
- Oficina Tècnica de Parcs Naturals. Diputació de Barcelona Barcelona Spain
| | - Koen Chiers
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Albert Ferran
- Oficina Tècnica de Parcs Naturals. Diputació de Barcelona Barcelona Spain
| | - Moira Kelly
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Mariona Picart
- Oficina Tècnica de Parcs Naturals. Diputació de Barcelona Barcelona Spain
| | - Dolors Piulats
- Institute of Evolutionary Biology (CSIC‐UPF) Barcelona Spain
| | - Zhimin Li
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
| | - Viviana Pagone
- Institute of Evolutionary Biology (CSIC‐UPF) Barcelona Spain
| | - Laia Pérez‐Sorribes
- Grup de Recerca de l'Escola de la Natura de Parets del Vallès – Ajuntament de Parets del Vallès Parets del Vallès Spain
| | - Carolina Molina
- Grup de Recerca de l'Escola de la Natura de Parets del Vallès – Ajuntament de Parets del Vallès Parets del Vallès Spain
| | - Aïda Tarragó‐Guarro
- Departament de Territori i SostenibilitatGeneralitat de Catalunya Barcelona Spain
| | - Roser Velarde‐Nieto
- Departament de Medicina i Cirurgia AnimalsFacultat de VeterinàriaUniversitat Autònoma de Barcelona Bellaterra Spain
| | - Francesc Carbonell
- Àrea de Gestió Ambiental Servei de Fauna i Flora (Centre de Fauna de Torreferrussa) Santa Perpètua de Mogoda Spain
| | - Elena Obon
- Àrea de Gestió Ambiental Servei de Fauna i Flora (Centre de Fauna de Torreferrussa) Santa Perpètua de Mogoda Spain
| | | | - Daniel Guinart
- Oficina Tècnica de Parcs Naturals. Diputació de Barcelona Barcelona Spain
| | - Ricard Casanovas
- Departament de Territori i SostenibilitatGeneralitat de Catalunya Barcelona Spain
| | | | - Frank Pasmans
- Wildlife Health GhentDepartment of PathologyBacteriology and Avian Diseases, Faculty of Veterinary MedicineGhent University Merelbeke Belgium
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37
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Barnhart KL, Bletz MC, LaBumbard BC, Tokash-Peters AG, Gabor CR, Woodhams DC. Batrachochytrium salamandrivorans ELICITS ACUTE STRESS RESPONSE IN SPOTTED SALAMANDERS BUT NOT INFECTION OR MORTALITY. Anim Conserv 2020; 23:533-546. [PMID: 33071596 DOI: 10.1111/acv.12565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emerging fungal pathogen Batrachochytrium salamandrivorans (Bsal) is a major threat to amphibian species worldwide with potential to infect many species if it invades salamander biodiversity hotspots in the Americas. Bsal can cause the disease chytridiomycosis, and it is important to assess the risk of Bsal-induced chytridiomycosis to species in North America. We evaluated the susceptibility to Bsal of the common and widespread spotted salamander, Ambystoma maculatum, across life history stages and monitored the effect of Bsal exposure on growth rate and response of the stress hormone, corticosterone. We conclude that spotted salamanders appear resistant to Bsal because they showed no indication of disease or infection, and experienced minor effects on growth upon exposure. While we focused on a single population for this study, results were consistent across conditions of exposure including high or repeated doses of Bsal, life-stage at exposure, environmental conditions including two temperatures and two substrates, and promoting pathogen infectivity by conditioning Bsal cultures with thyroid hormone. Exposure to high levels of Bsal elicited an acute but not chronic increase in corticosterone in spotted salamanders, and reduced growth. We hypothesize that the early acute increase in corticosterone facilitated mounting an immune response to the pathogen, perhaps through immunoredistribution to the skin, but further study is needed to determine immune responses to Bsal. These results will contribute to development of appropriate Bsal management plans to conserve species at risk of emerging disease.
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Affiliation(s)
- Kelly L Barnhart
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Molly C Bletz
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Brandon C LaBumbard
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Amanda G Tokash-Peters
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Caitlin R Gabor
- Texas State University, Department of Biology, 601 University Drive, San Marcos, TX 78666
| | - Douglas C Woodhams
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
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Widespread chytrid infection across frogs in the Peruvian Amazon suggests critical role for low elevation in pathogen spread and persistence. PLoS One 2019; 14:e0222718. [PMID: 31618214 PMCID: PMC6795419 DOI: 10.1371/journal.pone.0222718] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 09/05/2019] [Indexed: 12/03/2022] Open
Abstract
Outbreaks of emerging infectious diseases are becoming more frequent as climate changes wildlife communities at unprecedented rates, driving population declines and raising concerns for species conservation. One critical disease is the global pandemic of chytridiomycosis in frogs, which can be caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Although there is clear evidence for Bd-induced mortality across high-elevation frog communities, little attention is given to the role of lowlands in Bd’s persistence and spread because low elevations are assumed to be too warm to harbor significant levels of Bd. Here, we report widespread Bd infection across 80 frog species from three sites in the lowland Peruvian Amazon, an area with no documented Bd-related amphibian declines. Despite observing no clinical signs of infection in the field, we found that 24–46% of individuals were infected per site (up to ≈105,000 zoospore equivalents per frog) by three Bd strains from the global pandemic lineage (Bd-GPL). We also found collection site and seasonal effects to be only weak predictors of Bd prevalence and load, with lower elevation and drier habitats marginally decreasing both prevalence and load. We found no further effect of host phylogeny, ecotype, or body size. Our results showing high and widespread prevalence across a lowland tropical ecosystem contradict the expectations based on the global pattern of pathogenicity of Bd that is largely restricted to higher elevations and colder temperatures. These findings imply that the lowlands may play a critical role in the spread and persistence of Bd over time and space.
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Canessa S, Bozzuto C, Pasmans F, Martel A. Quantifying the burden of managing wildlife diseases in multiple host species. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2019; 33:1131-1140. [PMID: 30868671 DOI: 10.1111/cobi.13313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/20/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Mitigation of infectious wildlife diseases is especially challenging where pathogens affect communities of multiple host species. Although most ecological studies recognize the challenge posed by multiple-species pathogens, the implications for management are typically assessed only qualitatively. Translating the intuitive understanding that multiple host species are important into practice requires a quantitative assessment of whether and how secondary host species should also be targeted by management and the effort this will require. Using a multiple-species compartmental model, we determined analytically whether and how intensively secondary host species should be managed to prevent outbreaks in focal hosts based on the reproduction number of individual host species and between-species transmission rates. We applied the model to the invasive pathogenic fungus Batrachochytrium salamandrivorans in a 2-host system in northern Europe. Avoiding a disease outbreak in the focal host (fire salamanders [Salamandra salamandra]) was impossible unless management also heavily targeted the secondary host (alpine newts [Ichthyosaura alpestris]). Preventing an outbreak in the community required targeted removal of at least 80% of each species. This proportion increased to 90% in the presence of an environmental reservoir of B. salamandrivorans and when the proportion of individuals removed could not be adjusted for different host species (e.g., when using traps that are not species specific). We recommend the focus of disease-mitigation plans should shift from focal species to the community level and calculate explicitly the management efforts required on secondary host species to move beyond the simple intuitive understanding that multiple host species may all influence the system. Failure to do so may lead to underestimating the magnitude of the effort required and ultimately to suboptimal or futile management attempts.
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Affiliation(s)
- Stefano Canessa
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Claudio Bozzuto
- Wildlife Analysis GmbH, Oetlisbergstrasse 38, 8053, Zurich, Switzerland
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
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40
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Carter ED, Miller DL, Peterson AC, Sutton WB, Cusaac JPW, Spatz JA, Rollins‐Smith L, Reinert L, Bohanon M, Williams LA, Upchurch A, Gray MJ. Conservation risk of
Batrachochytrium salamandrivorans
to endemic lungless salamanders. Conserv Lett 2019. [DOI: 10.1111/conl.12675] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Edward Davis Carter
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Debra L. Miller
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
- Department of Biomedical and Diagnostic Sciences, College of Veterinary MedicineUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Anna C. Peterson
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - William B. Sutton
- Department of Agricultural and Environmental SciencesTennessee State University Nashville Tennessee
| | - Joseph Patrick W. Cusaac
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Jennifer A. Spatz
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Louise Rollins‐Smith
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Laura Reinert
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Markese Bohanon
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Lori A. Williams
- North Carolina Wildlife Resources Commission Raleigh North Carolina
| | | | - Matthew J. Gray
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
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Historical records reveal the distinctive associations of human disturbance and extreme climate change with local extinction of mammals. Proc Natl Acad Sci U S A 2019; 116:19001-19008. [PMID: 31481618 PMCID: PMC6754601 DOI: 10.1073/pnas.1818019116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Human impacts and climatic changes are widely considered to be responsible for rapid species extinction. However, determining their effects is challenging owing to the lack of long-term spatial–temporal data. In this study, we quantified the distinctive associations of anthropogenic and climatic stressors with the local extinction of 11 medium- or large-sized mammals using historical records over the past 3 centuries. We found that the increased local extinction of mammals was associated with intensified human disturbance (particularly for large-sized mammals) and with extreme temperature change (both cooling and warming). Our results provide insight into biodiversity conservation during the Anthropocene. Accelerated anthropogenic impacts and climatic changes are widely considered to be responsible for unprecedented species extinction. However, determining their effects on extinction is challenging owing to the lack of long-term data with high spatial and temporal resolution. In this study, using historical occurrence records of 11 medium- to large-sized mammal species or groups of species in China from 905 BC to AD 2006, we quantified the distinctive associations of anthropogenic stressors (represented by cropland coverage and human population density) and climatic stressors (represented by air temperature) with the local extinction of these mammals. We found that both intensified human disturbances and extreme climate change were associated with the increased local extinction of the study mammals. In the cold phase (the premodern period of China), climate cooling was positively associated with increased local extinction, while in the warm phase (the modern period) global warming was associated with increased local extinction. Interactive effects between human disturbance and temperature change with the local extinction of elephants, rhinos, pandas, and water deer were found. Large-sized mammals, such as elephants, rhinos, and pandas, showed earlier and larger population declines than small-sized ones. The local extinction sensitivities of these mammals to the human population density and standardized temperature were estimated during 1700 to 2000. The quantitative evidence for anthropogenic and climatic associations with mammalian extinction provided insights into the driving processes of species extinction, which has important implications for biodiversity conservation under accelerating global changes.
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Bates KA, Shelton JMG, Mercier VL, Hopkins KP, Harrison XA, Petrovan SO, Fisher MC. Captivity and Infection by the Fungal Pathogen Batrachochytrium salamandrivorans Perturb the Amphibian Skin Microbiome. Front Microbiol 2019; 10:1834. [PMID: 31507541 PMCID: PMC6716147 DOI: 10.3389/fmicb.2019.01834] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
The emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal) is responsible for the catastrophic decline of European salamanders and poses a threat to amphibians globally. The amphibian skin microbiome can influence disease outcome for several host-pathogen systems, yet little is known of its role in Bsal infection. In addition, many experimental in-vivo amphibian disease studies to date have relied on specimens that have been kept in captivity for long periods without considering the influence of environment on the microbiome and how this may impact the host response to pathogen exposure. We characterized the impact of captivity and exposure to Bsal on the skin bacterial and fungal communities of two co-occurring European newt species, the smooth newt, Lissotriton vulgaris and the great-crested newt, Triturus cristatus. We show that captivity led to significant losses in bacterial and fungal diversity of amphibian skin, which may be indicative of a decline in microbe-mediated protection. We further demonstrate that in both L. vulgaris and T. cristatus, Bsal infection was associated with changes in the composition of skin bacterial communities with possible negative consequences to host health. Our findings advance current understanding of the role of host-associated microbiota in Bsal infection and highlight important considerations for ex-situ amphibian conservation programmes.
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Affiliation(s)
- Kieran A Bates
- Department of Zoology, University of Oxford, Oxford, United Kingdom.,Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.,Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Jennifer M G Shelton
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Victoria L Mercier
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Kevin P Hopkins
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Silviu O Petrovan
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Froglife, Peterborough, United Kingdom
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
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Ellison S, Rovito S, Parra-Olea G, Vásquez-Almazán C, Flechas SV, Bi K, Vredenburg VT. The Influence of Habitat and Phylogeny on the Skin Microbiome of Amphibians in Guatemala and Mexico. MICROBIAL ECOLOGY 2019; 78:257-267. [PMID: 30467714 DOI: 10.1007/s00248-018-1288-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Microbial symbionts are increasingly recognized as playing a critical role in organismal health across a wide range of hosts. Amphibians are unique hosts in that their skin helps to regulate the exchange of water, ions, and gases, and it plays an active role in defense against pathogens through the synthesis of anti-microbial peptides. The microbiome of amphibian skin includes a diverse community of bacteria known to defend against pathogens, including the global pandemic lineage of Batrachochytrium dendrobatidis associated with mass amphibian die-offs. The relative influence of host phylogeny and environment in determining the composition of the amphibian skin microbiome remains poorly understood. We collected skin swabs from montane amphibians in Mexico and Guatemala, focusing on two genera of plethodontid salamanders and one genus of frogs. We used high throughput sequencing to characterize the skin bacterial microbiome and tested the impact of phylogeny and habitat on bacterial diversity. Our results show that phylogenetic history strongly influences the diversity and community structure of the total bacterial microbiome at higher taxonomic levels (between orders), but on lower scales (within genera and species), the effect of habitat predominates. These results add to a growing consensus that habitat exerts a strong effect on microbiome structure and composition, particularly at shallow phylogenetic scales.
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Affiliation(s)
- Silas Ellison
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
| | - Sean Rovito
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA.
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 Libramiento Norte Carretera Irapuato-León, 36824, Irapuato, Guanajuato, Mexico.
| | - Gabriela Parra-Olea
- Departamento de Zoología, Insituto de Biología, Universidad Nacional Autónoma de México, CP04510, México, DF, Mexico
| | - Carlos Vásquez-Almazán
- Museo de Historia Natural y Escuela de Biología, Universidad de San Carlos, Guatemala, Guatemala
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de los Andes, AA 4976, Bogotá, Colombia
- Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia
| | - Ke Bi
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
- Computational Genomics Resource Laboratory, California Institute for Quantitative Biosciences University of California, Berkeley, CA, 94720, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
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The importance of biological plausibility for data poor models in the face of an immediate threat by an emerging infectious disease: a reply to Katz and Zellmer (2018). Biol Invasions 2019. [DOI: 10.1007/s10530-019-02035-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Longo AV, Fleischer RC, Lips KR. Double trouble: co-infections of chytrid fungi will severely impact widely distributed newts. Biol Invasions 2019. [DOI: 10.1007/s10530-019-01973-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Hygiene and biosecurity protocols reduce infection prevalence but do not improve fledging success in an endangered parrot. Sci Rep 2019; 9:4779. [PMID: 30886308 PMCID: PMC6423005 DOI: 10.1038/s41598-019-41323-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 03/01/2019] [Indexed: 12/11/2022] Open
Abstract
Emerging Infectious Diseases (EIDs) are recognised as global extinction drivers of threatened species. Unfortunately, biodiversity managers have few tested solutions to manage them when often the desperate need for solutions necessitates a response. Here we test in situ biosecurity protocols to assess the efficacy of managing Psittacine beak and feather disease (PBFD), one of the most common and emergent viral diseases in wild parrots (Psittaciformes) that is currently affecting numerous threatened species globally. In response to an outbreak of PBFD in Mauritius “echo” parakeets (Psittacula eques), managers implemented a set of biosecurity protocols to limit transmission and impact of Beak and feather disease virus (BFDV). Here we used a reciprocal design experiment on the wild population to test whether BFDV management reduced viral prevalence and viral load, and improved nestling body condition and fledge success. Whilst management reduced the probability of nestling infection by approximately 11% there was no observed impact on BFDV load and nestling body condition. In contrast to expectations there was lower fledge success in nests with added BFDV biosecurity (83% in untreated vs. 79% in treated nests). Our results clearly illustrate that management for wildlife conservation should be critically evaluated through targeted monitoring and experimental manipulation, and this evaluation should always focus on the fundamental objective of conservation.
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Measey J, Basson A, Rebelo AD, Nunes AL, Vimercati G, Louw M, Mohanty NP. Why Have a Pet Amphibian? Insights From YouTube. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00052] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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48
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Basanta MD, Rebollar EA, Parra-Olea G. Potential risk of Batrachochytrium salamandrivorans in Mexico. PLoS One 2019; 14:e0211960. [PMID: 30753218 PMCID: PMC6372179 DOI: 10.1371/journal.pone.0211960] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/24/2019] [Indexed: 02/07/2023] Open
Abstract
The recent decline in populations of European salamanders caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) has generated worldwide concern, as it is a major threat to amphibians. Evaluation of the areas most suitable for the establishment of Bsal combined with analysis of the distribution of salamander species could be used to generate and implement biosecurity measures and protect biodiversity at sites with high salamander diversity. In this study, we identified the areas most suitable for the establishment of Bsal in Mexico. Mexico has the second-highest salamander species diversity in the world; thus, we identified areas moderately to highly suitable for the establishment of Bsal with high salamander diversity as potential hotspots for surveillance. Central and Southern Mexico were identified as high-risk zones, with 13 hotspots where 30% of Mexican salamander species occur, including range-restricted species and endangered species. We propose that these hotspots should be thoroughly monitored for the presence of Bsal to prevent the spread of the pathogen if it is introduced to the country.
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Affiliation(s)
- M. Delia Basanta
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, AP, Tercer Circuito Exterior s/ n, Ciudad Universitaria, Ciudad de México, México
- Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio A, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, C.P., Ciudad de México, México
| | - Eria A. Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Gabriela Parra-Olea
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, AP, Tercer Circuito Exterior s/ n, Ciudad Universitaria, Ciudad de México, México
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Fitzpatrick LD, Pasmans F, Martel A, Cunningham AA. Epidemiological tracing of Batrachochytrium salamandrivorans identifies widespread infection and associated mortalities in private amphibian collections. Sci Rep 2018; 8:13845. [PMID: 30218076 PMCID: PMC6138723 DOI: 10.1038/s41598-018-31800-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/23/2018] [Indexed: 12/17/2022] Open
Abstract
The amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) infects newts and salamanders (urodele amphibians), in which it can cause fatal disease. This pathogen has caused dramatic fire salamander population declines in Belgium, the Netherlands and Germany since its discovery in 2010. Thought to be native to Asia, it has been hypothesised that Bsal was introduced to Europe with the importation of infected amphibians for the commercial pet trade. Following the discovery of Bsal in captive amphibians in the United Kingdom in 2015, we used contact-tracing to identify epidemiologically-linked private amphibian collections in Western Europe. Of 16 linked collections identified, animals were tested from 11 and urodeles tested positive for Bsal in seven, including the identification of the pathogen in Spain for the first time. Mortality of Bsal-positive individuals was observed in five collections. Our results indicate that Bsal is likely widespread within the private amphibian trade, at least in Europe. These findings are important for informing policy regarding Bsal control strategies.
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Affiliation(s)
- Liam D Fitzpatrick
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK.
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50
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Adams MJ, Harris RN, Grant EHC, Gray MJ, Camille Hopkins M, Iverson SA, Likens R, Mandica M, Olson DH, Shepack A, Waddle H. Prepublication Communication of Research Results. ECOHEALTH 2018; 15:478-481. [PMID: 30088185 PMCID: PMC6245104 DOI: 10.1007/s10393-018-1352-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/30/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Affiliation(s)
- Michael J Adams
- Forest and Rangeland Ecosystem Science Center, U.S. Geological Survey, 3200 SW Jefferson Way, Corvallis, OR, 97330, USA.
| | - Reid N Harris
- Department of Biology, MSC 7801, James Madison University, Harrisonburg, USA
| | - Evan H C Grant
- Patuxent Wildlife Research Center and SO Conte Anadromous Fish Laboratory, U.S. Geological Survey, Laurel, USA
| | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, USA
| | | | - Samuel A Iverson
- Wildlife Health Section, Environment and Climate Change, Canadian Wildlife Service, Gatineau, Canada
| | - Robert Likens
- Pet Industry Joint Advisory Council, Alexandria, USA
| | | | | | - Alex Shepack
- Department of Biological Sciences, Florida International University, Miami, USA
| | - Hardin Waddle
- Wetland and Aquatic Research Center, U.S. Geological Survey, Gainseville, USA
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