151
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Hanlon SM, Henson JR, Kerby JL. Detection of amphibian chytrid fungus on waterfowl integument in natural settings. DISEASES OF AQUATIC ORGANISMS 2017; 126:71-74. [PMID: 28930087 DOI: 10.3354/dao03160] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The chytrid fungus Batrachochytrium dendrobatidis (Bd), the causal agent of the amphibian disease chytridiomycosis, has spread at an alarming rate since its discovery. Bd was initially thought to only infect keratinizing epithelial cells in amphibians, a core component of amphibian skin. However, recent studies have detected Bd on the integument of non-amphibian hosts. We conducted a survey of 3 duck species (gadwalls, green-winged teals, and mallards) to determine whether Bd DNA could be found on their feet. Bd was found on the feet, by quantitative PCR, of individuals from all 3 species (5/11 gadwalls, 4/8 green-winged teals, and 13/21 mallards), though there were no significant differences in zoospore presence or load between species. We conclude that these waterfowl species may act as vector hosts for Bd, adding to the growing list of potential waterfowl vectors. Future studies are needed to determine whether Bd on waterfowl feet is viable and infectious to amphibian hosts.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, Tennessee 38152, USA
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152
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DiRenzo GV, Campbell Grant EH, Longo AV, Che‐Castaldo C, Zamudio KR, Lips KR. Imperfect pathogen detection from non‐invasive skin swabs biases disease inference. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12868] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Evan H. Campbell Grant
- U.S. Geological Survey Patuxent Wildlife Research Center SO Conte Anadromous Fish Research Lab Turners Falls MA USA
| | - Ana V. Longo
- Department of Biology University of Maryland College Park MD USA
| | | | - Kelly R. Zamudio
- Department of Ecology & Evolutionary Biology Cornell University Ithaca NY USA
| | - Karen R. Lips
- Department of Biology University of Maryland College Park MD USA
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153
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Pathogenic lineage of Perkinsea associated with mass mortality of frogs across the United States. Sci Rep 2017; 7:10288. [PMID: 28860470 PMCID: PMC5579288 DOI: 10.1038/s41598-017-10456-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/08/2017] [Indexed: 01/31/2023] Open
Abstract
Emerging infectious diseases such as chytridiomycosis and ranavirus infections are important contributors to the worldwide decline of amphibian populations. We reviewed data on 247 anuran mortality events in 43 States of the United States from 1999–2015. Our findings suggest that a severe infectious disease of tadpoles caused by a protist belonging to the phylum Perkinsea might represent the third most common infectious disease of anurans after ranavirus infections and chytridiomycosis. Severe Perkinsea infections (SPI) were systemic and led to multiorganic failure and death. The SPI mortality events affected numerous anuran species and occurred over a broad geographic area, from boreal to subtropical habitats. Livers from all PCR-tested SPI-tadpoles (n = 19) were positive for the Novel Alveolate Group 01 (NAG01) of Perkinsea, while only 2.5% histologically normal tadpole livers tested positive (2/81), suggesting that subclinical infections are uncommon. Phylogenetic analysis demonstrated that SPI is associated with a phylogenetically distinct clade of NAG01 Perkinsea. These data suggest that this virulent Perkinsea clade is an important pathogen of frogs in the United States. Given its association with mortality events and tendency to be overlooked, the potential role of this emerging pathogen in amphibian declines on a broad geographic scale warrants further investigation.
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154
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Hydeman ME, Longo AV, Velo-Antón G, Rodriguez D, Zamudio KR, Bell RC. Prevalence and genetic diversity of Batrachochytrium dendrobatidis in Central African island and continental amphibian communities. Ecol Evol 2017; 7:7729-7738. [PMID: 29043029 PMCID: PMC5632636 DOI: 10.1002/ece3.3309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 07/07/2017] [Accepted: 07/12/2017] [Indexed: 01/14/2023] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) infects hundreds of amphibian species and is implicated in global amphibian declines. Bd is comprised of several lineages that differ in pathogenicity, thus, identifying which Bd strains are present in a given amphibian community is essential for understanding host–pathogen dynamics. The presence of Bd has been confirmed in Central Africa, yet vast expanses of this region have not yet been surveyed for Bd prevalence, and the genetic diversity of Bd is largely unknown in this part of the world. Using retrospective surveys of museum specimens and contemporary field surveys, we estimated the prevalence of Bd in Central African island and continental amphibian assemblages, and genotyped strains of Bd present in each community. Our sampling of museum specimens included just a few individuals collected in the Gulf of Guinea archipelago prior to 1998, yet one of these individuals was Bd‐positive indicating that the pathogen has been on Bioko Island since 1966. We detected Bd across all subsequent sample years in our study and found modest support for a relationship between host life history and Bd prevalence, a positive relationship between prevalence and host community species richness, and no significant relationship between elevation and prevalence. The Global Panzootic Lineage (BdGPL) was present in all the island and continental amphibian communities we surveyed. Our results are consistent with a long‐term and widespread distribution of Bd in amphibian communities of Gabon and the Gulf of Guinea archipelago.
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Affiliation(s)
- Marina E Hydeman
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
| | - Ana V Longo
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
| | - Guillermo Velo-Antón
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA.,CIBIO-InBIO Universidade do Porto Campus Agrário de Vairão Vairão Portugal
| | - David Rodriguez
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA.,Department of Biology Texas State University San Marcos TX USA
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
| | - Rayna C Bell
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA.,Department of Vertebrate Zoology National Museum of Natural History Smithsonian Institution Washington DC USA
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155
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Chytrid Infection Dynamics in Cricket Frogs on Military and Public Lands in the Midwestern United States. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2017. [DOI: 10.3996/012017-jfwm-003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
The pathogenic chytrid fungus Batrachochytrium dendrobatidis (hereafter, Bd) is a causal agent in amphibian decline and extinction events. Sampling for Bd in the Midwestern United States has largely been opportunistic and haphazard, so little information exists on the true occurrence and prevalence of the disease. We repeatedly tested Cricket Frogs Acris blanchardi or A. crepitans at 54 wetlands in 2009 and 15 wetlands in 2011 on both public and military lands to estimate Bd occurrence and prevalence rates between different land-use types, sampling seasons (spring, summer, autumn) and sampling years. We found Bd occurred in 100% of wetlands we sampled in 2009 and 2011, and overall prevalence was 22.7% in 2009 and 40.5% in 2011. Batrachochytrium dendrobatidis prevalence in 2011 was significantly higher than in 2009 and was significantly higher during the spring season than in the summer or autumn. We also found Bd prevalence was not significantly different on military versus public-use sites and was most affected by the average 30-d maximum temperature prior to sampling. This study provides data on the occurrence and prevalence of Bd in the United States and fills an important gap in the Midwest, while also corroborating prior research findings of increased prevalence in the cooler spring season.
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156
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Al-Shorbaji F, Roche B, Britton R, Andreou D, Gozlan R. Influence of predation on community resilience to disease. J Anim Ecol 2017; 86:1147-1158. [PMID: 28758196 DOI: 10.1111/1365-2656.12722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/01/2017] [Indexed: 02/05/2023]
Abstract
Outbreaks of generalist pathogens are influenced by host community structure, including population density and species diversity. Within host communities predation can influence pathogen transmission rates, prevalence and impacts. However, the influence of predation on community resilience to outbreaks of generalist pathogens is not fully understood. The role of predation on host community resilience to disease was assessed using an epidemiological multi-host susceptible-exposed-infectious-recovered model. Sphaerothecum destruens, an emerging fungal-like generalist pathogen, was used as a model pathogen. Six cyprinid and salmonid fishes, including an asymptomatic carrier, were selected as model hosts that are known to be impacted by S. destruens, and they were used within a model host community. Pathogen release into the host community was via introduction of the asymptomatic carrier. Mortality from infection, pathogen incubation rate, and host recovery rate were set to a range of evidence-based values in each species and were varied in secondary consumers to predict top-down effects of infection on the resilience of a host community. Predation pressure within the fish community was varied to test its effects on infection prevalence and host survival in the community. Model predictions suggested that predation of the asymptomatic hosts by fishes in the host community was insufficient to eliminate S. destruens. Sphaerothecum destruens persisted in the community due to its rapid transmission from the asymptomatic host to susceptible host fishes. Following transmission, pathogen prevalence in the community was driven by transmission within and between susceptible host fishes, indicating low host community resilience. However, introducing low densities of a highly specific piscivorous fish into the community to pre-date asymptomatic hosts could limit pathogen prevalence in the host community, thus increasing resilience. The model predictions indicate that whilst resilience to this generalist pathogen in the host community was low, this could be increased using management interventions. The results suggest that this model has high utility for predicting community resilience to disease and thus can be applied to other generalist parasites to determine risks of disease emergence.
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Affiliation(s)
- Farah Al-Shorbaji
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Benjamin Roche
- Unit for Mathematical and Computer Modelling of Complex Systems, Institute of Research for Development, Montpellier, France.,Institut de Recherche pour le Développement UMR MIVEGEC IRD-CNRS-Université de Montpellier, Centre IRD de Montpellier, Montpellier, France
| | - Robert Britton
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Demetra Andreou
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Rodolphe Gozlan
- Institut de Recherche pour le Développement UMR MIVEGEC IRD-CNRS-Université de Montpellier, Centre IRD de Montpellier, Montpellier, France.,Institut de Recherche pour le Développement UMR BOREA IRD-MNHN-Université Pierre et Marie Curie, Muséum National d'Histoire Naturelle, Paris Cedex 5, France
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157
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Walke JB, Becker MH, Hughey MC, Swartwout MC, Jensen RV, Belden LK. Dominance‐function relationships in the amphibian skin microbiome. Environ Microbiol 2017; 19:3387-3397. [DOI: 10.1111/1462-2920.13850] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Myra C. Hughey
- Department of Biological SciencesVirginia TechBlacksburg VA USA
| | | | | | - Lisa K. Belden
- Department of Biological SciencesVirginia TechBlacksburg VA USA
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158
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Blooi M, Laking AE, Martel A, Haesebrouck F, Jocque M, Brown T, Green S, Vences M, Bletz MC, Pasmans F. Host niche may determine disease-driven extinction risk. PLoS One 2017; 12:e0181051. [PMID: 28704480 PMCID: PMC5509289 DOI: 10.1371/journal.pone.0181051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 06/26/2017] [Indexed: 12/31/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) drives declines and extinctions in amphibian communities. However, not all regions and species are equally affected. Here, we show that association with amphibian aquatic habitat types (bromeliad phytotelmata versus stream) across Central America results in the odds of being threatened by Bd being five times higher in stream microhabitats. This differential threat of Bd was supported in our study by a significantly lower prevalence of Bd in bromeliad-associated amphibian species compared to riparian species in Honduran cloud forests. Evidence that the bromeliad environment is less favorable for Bd transmission is exemplified by significantly less suitable physicochemical conditions and higher abundance of Bd-ingesting micro-eukaryotes present in bromeliad water. These factors may inhibit aquatic Bd zoospore survival and the development of an environmental reservoir of the pathogen. Bromeliad phytotelmata thus may act as environmental refuges from Bd, which contribute to protecting associated amphibian communities against chytridiomycosis-driven amphibian declines that threaten the nearby riparian communities.
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Affiliation(s)
- Mark Blooi
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Alexandra E. Laking
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Merlijn Jocque
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Tom Brown
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
| | - Stephen Green
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
- Centre for Applied Zoology, Cornwall College Newquay, Cornwall, United Kingdom
| | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Molly C. Bletz
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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159
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Abstract
While fungi can make positive contributions to ecosystems and agro-ecosystems, for example, in mycorrhizal associations, they can also have devastating impacts as pathogens of plants and animals. In undisturbed ecosystems, most such negative interactions will be limited through the coevolution of fungi with their hosts. In this article, we explore what happens when pathogenic fungi spread beyond their natural ecological range and become invasive on naïve hosts in new ecosystems. We will see that such invasive pathogens have been problematic to humans and their domesticated plant and animal species throughout history, and we will discuss some of the most pressing fungal threats of today.
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160
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Medina D, Hughey MC, Becker MH, Walke JB, Umile TP, Burzynski EA, Iannetta A, Minbiole KPC, Belden LK. Variation in Metabolite Profiles of Amphibian Skin Bacterial Communities Across Elevations in the Neotropics. MICROBIAL ECOLOGY 2017; 74:227-238. [PMID: 28105509 DOI: 10.1007/s00248-017-0933-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
Both the structure and function of host-associated microbial communities are potentially impacted by environmental conditions, just as the outcomes of many free-living species interactions are context-dependent. Many amphibian populations have declined around the globe due to the fungal skin pathogen, Batrachochytrium dendrobatidis (Bd), but enivronmental conditions may influence disease dynamics. For instance, in Panamá, the most severe Bd outbreaks have occurred at high elevation sites. Some amphibian species harbor bacterial skin communities that can inhibit the growth of Bd, and therefore, there is interest in understanding whether environmental context could also alter these host-associated microbial communities in a way that might ultimately impact Bd dynamics. In a field survey in Panamá, we assessed skin bacterial communities (16S rRNA amplicon sequencing) and metabolite profiles (HPLC-UV/Vis) of Silverstoneia flotator from three high- and three low-elevation populations representing a range of environmental conditions. Across elevations, frogs had similar skin bacterial communities, although one lowland site appeared to differ. Interestingly, we found that bacterial richness decreased from west to east, coinciding with the direction of Bd spread through Panamá. Moreover, metabolite profiles suggested potential functional variation among frog populations and between elevations. While the frogs have similar bacterial community structure, the local environment might shape the metabolite profiles. Ultimately, host-associated community structure and function could be dependent on environmental conditions, which could ultimately influence host disease susceptibility across sites.
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Affiliation(s)
- Daniel Medina
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA.
| | - Myra C Hughey
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA
| | - Matthew H Becker
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA
| | - Jenifer B Walke
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA
| | - Thomas P Umile
- Department of Chemistry, Villanova University, Villanova, PA, USA
| | | | - Anthony Iannetta
- Department of Chemistry, Villanova University, Villanova, PA, USA
| | | | - Lisa K Belden
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall (0406), Blacksburg, VA, 24061, USA
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161
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The Emerging Amphibian Fungal Disease, Chytridiomycosis: A Key Example of the Global Phenomenon of Wildlife Emerging Infectious Diseases. Microbiol Spectr 2017; 4. [PMID: 27337484 DOI: 10.1128/microbiolspec.ei10-0004-2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spread of amphibian chytrid fungus, Batrachochytrium dendrobatidis, is associated with the emerging infectious wildlife disease chytridiomycosis. This fungus poses an overwhelming threat to global amphibian biodiversity and is contributing toward population declines and extinctions worldwide. Extremely low host-species specificity potentially threatens thousands of the 7,000+ amphibian species with infection, and hosts in additional classes of organisms have now also been identified, including crayfish and nematode worms.Soon after the discovery of B. dendrobatidis in 1999, it became apparent that this pathogen was already pandemic; dozens of countries and hundreds of amphibian species had already been exposed. The timeline of B. dendrobatidis's global emergence still remains a mystery, as does its point of origin. The reason why B. dendrobatidis seems to have only recently increased in virulence to catalyze this global disease event remains unknown, and despite 15 years of investigation, this wildlife pandemic continues primarily uncontrolled. Some disease treatments are effective on animals held in captivity, but there is currently no proven method to eradicate B. dendrobatidis from an affected habitat, nor have we been able to protect new regions from exposure despite knowledge of an approaching "wave" of B. dendrobatidis and ensuing disease.International spread of B. dendrobatidis is largely facilitated by the commercial trade in live amphibians. Chytridiomycosis was recently listed as a globally notifiable disease by the World Organization for Animal Health, but few countries, if any, have formally adopted recommended measures to control its spread. Wildlife diseases continue to emerge as a consequence of globalization, and greater effort is urgently needed to protect global health.
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162
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Kolenda K, Najbar A, Ogielska M, Balá V. Batrachochytrium dendrobatidis is present in Poland and associated with reduced fitness in wild populations of Pelophylax lessonae. DISEASES OF AQUATIC ORGANISMS 2017; 124:241-245. [PMID: 28492180 DOI: 10.3354/dao03121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The fungus Batrachochytrium dendrobatidis (Bd) is a pathogen associated with global declines of amphibians. We used qPCR to detect Bd in 255 samples from 10 Polish populations of 8 species. We found Bd infection in 3 species (Bombina variegata, Pelophylax lessonae, P. esculentus). The infection intensity in P. lessonae reached a maximum of 58400 genomic equivalents of zoospores (GE), and the 2 most heavily infected individuals died. Previous observations of the populations that included infected individuals showed reduced body size, failure to reproduce, and mortalities of adults. These data highlight the importance of emerging diseases, and the need to recognize them as an important factor in conservation of the genus Pelophylax in Poland and Central and Eastern Europe.
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Affiliation(s)
- Krzysztof Kolenda
- Department of Evolutionary Biology and Conservation of Vertebrates, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland
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163
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Byrne AQ, Rothstein AP, Poorten TJ, Erens J, Settles ML, Rosenblum EB. Unlocking the story in the swab: A new genotyping assay for the amphibian chytrid fungus
Batrachochytrium dendrobatidis. Mol Ecol Resour 2017; 17:1283-1292. [DOI: 10.1111/1755-0998.12675] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/26/2016] [Accepted: 03/15/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Allison Q. Byrne
- Department of Environmental Science Policy and Management University of California, Berkeley Berkeley CA USA
| | - Andrew P. Rothstein
- Department of Environmental Science Policy and Management University of California, Berkeley Berkeley CA USA
| | - Thomas J. Poorten
- Department of Environmental Science Policy and Management University of California, Berkeley Berkeley CA USA
| | - Jesse Erens
- Department of Environmental Science Policy and Management University of California, Berkeley Berkeley CA USA
- Wageningen University Wageningen The Netherlands
| | | | - Erica Bree Rosenblum
- Department of Environmental Science Policy and Management University of California, Berkeley Berkeley CA USA
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164
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Chytrid fungus infection in zebrafish demonstrates that the pathogen can parasitize non-amphibian vertebrate hosts. Nat Commun 2017; 8:15048. [PMID: 28425465 PMCID: PMC5411484 DOI: 10.1038/ncomms15048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/23/2017] [Indexed: 01/07/2023] Open
Abstract
Aquatic chytrid fungi threaten amphibian biodiversity worldwide owing to their ability to rapidly expand their geographical distributions and to infect a wide range of hosts. Combating this risk requires an understanding of chytrid host range to identify potential reservoirs of infection and to safeguard uninfected regions through enhanced biosecurity. Here we extend our knowledge on the host range of the chytrid Batrachochytrium dendrobatidis by demonstrating infection of a non-amphibian vertebrate host, the zebrafish. We observe dose-dependent mortality and show that chytrid can infect and proliferate on zebrafish tissue. We also show that infection phenotypes (fin erosion, cell apoptosis and muscle degeneration) are direct symptoms of infection. Successful infection is dependent on disrupting the zebrafish microbiome, highlighting that, as is widely found in amphibians, commensal bacteria confer protection against this pathogen. Collectively, our findings greatly expand the limited tool kit available to study pathogenesis and host response to chytrid infection.
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165
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Dillon MJ, Bowkett AE, Bungard MJ, Beckman KM, O'Brien MF, Bates K, Fisher MC, Stevens JR, Thornton CR. Tracking the amphibian pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans using a highly specific monoclonal antibody and lateral-flow technology. Microb Biotechnol 2017; 10:381-394. [PMID: 27995742 PMCID: PMC5328824 DOI: 10.1111/1751-7915.12464] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/27/2016] [Indexed: 11/30/2022] Open
Abstract
The fungus Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a lethal epizootic disease of amphibians. Rapid identification of the pathogen and biosecurity is essential to prevent its spread, but current laboratory-based tests are time-consuming and require specialist equipment. Here, we describe the generation of an IgM monoclonal antibody (mAb), 5C4, specific to Bd as well as the related salamander and newt pathogen Batrachochytrium salamandrivorans (Bsal). The mAb, which binds to a glycoprotein antigen present on the surface of zoospores, sporangia and zoosporangia, was used to develop a lateral-flow assay (LFA) for rapid (15 min) detection of the pathogens. The LFA detects known lineages of Bd and also Bsal, as well as the closely related fungus Homolaphlyctis polyrhiza, but does not detect a wide range of related and unrelated fungi and oomycetes likely to be present in amphibian habitats. When combined with a simple swabbing procedure, the LFA was 100% accurate in detecting the water-soluble 5C4 antigen present in skin, foot and pelvic samples from frogs, newts and salamanders naturally infected with Bd or Bsal. Our results demonstrate the potential of the portable LFA as a rapid qualitative assay for tracking these amphibian pathogens and as an adjunct test to nucleic acid-based detection methods.
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Affiliation(s)
- Michael J. Dillon
- BiosciencesUniversity of ExeterGeoffrey Pope BuildingExeterEX4 4QDUK
| | | | | | | | | | - Kieran Bates
- Department of Infectious Disease EpidemiologyImperial College LondonLondonSW7 2AZUK
| | - Matthew C. Fisher
- Department of Infectious Disease EpidemiologyImperial College LondonLondonSW7 2AZUK
| | - Jamie R. Stevens
- BiosciencesUniversity of ExeterGeoffrey Pope BuildingExeterEX4 4QDUK
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166
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Schatz AM, Kramer AM, Drake JM. Accuracy of climate-based forecasts of pathogen spread. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160975. [PMID: 28405387 DOI: 10.5061/dryad.3p121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/03/2017] [Indexed: 05/26/2023]
Abstract
Species distribution models (SDMs) are a tool for predicting the eventual geographical range of an emerging pathogen. Most SDMs, however, rely on an assumption of equilibrium with the environment, which an emerging pathogen, by definition, has not reached. To determine if some SDM approaches work better than others for modelling the spread of emerging, non-equilibrium pathogens, we studied time-sensitive predictive performance of SDMs for Batrachochytrium dendrobatidis, a devastating infectious fungus of amphibians, using multiple methods trained on time-incremented subsets of the available data. We split our data into timeline-based training and testing sets, and evaluated models on each set using standard performance criteria, including AUC, kappa, false negative rate and the Boyce index. Of eight models examined, we found that boosted regression trees and random forests performed best, closely followed by MaxEnt. As expected, predictive performance generally improved with the length of time series used for model training. These results provide information on how quickly the potential extent of an emerging disease may be determined, and identify which modelling frameworks are likely to provide useful information during the early phases of pathogen expansion.
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Affiliation(s)
- Annakate M Schatz
- Odum School of Ecology , University of Georgia , 140 East Green Street, Athens, GA 30602 , USA
| | - Andrew M Kramer
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, GA 30602, USA; Center for the Ecology of Infectious Diseases, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
| | - John M Drake
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, GA 30602, USA; Center for the Ecology of Infectious Diseases, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
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167
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Schatz AM, Kramer AM, Drake JM. Accuracy of climate-based forecasts of pathogen spread. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160975. [PMID: 28405387 PMCID: PMC5383844 DOI: 10.1098/rsos.160975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/03/2017] [Indexed: 05/13/2023]
Abstract
Species distribution models (SDMs) are a tool for predicting the eventual geographical range of an emerging pathogen. Most SDMs, however, rely on an assumption of equilibrium with the environment, which an emerging pathogen, by definition, has not reached. To determine if some SDM approaches work better than others for modelling the spread of emerging, non-equilibrium pathogens, we studied time-sensitive predictive performance of SDMs for Batrachochytrium dendrobatidis, a devastating infectious fungus of amphibians, using multiple methods trained on time-incremented subsets of the available data. We split our data into timeline-based training and testing sets, and evaluated models on each set using standard performance criteria, including AUC, kappa, false negative rate and the Boyce index. Of eight models examined, we found that boosted regression trees and random forests performed best, closely followed by MaxEnt. As expected, predictive performance generally improved with the length of time series used for model training. These results provide information on how quickly the potential extent of an emerging disease may be determined, and identify which modelling frameworks are likely to provide useful information during the early phases of pathogen expansion.
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Affiliation(s)
- Annakate M. Schatz
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
| | - Andrew M. Kramer
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
- Center for the Ecology of Infectious Diseases, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
| | - John M. Drake
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
- Center for the Ecology of Infectious Diseases, University of Georgia, 140 East Green Street, Athens, GA 30602, USA
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168
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Cohen JM, Venesky MD, Sauer EL, Civitello DJ, McMahon TA, Roznik EA, Rohr JR. The thermal mismatch hypothesis explains host susceptibility to an emerging infectious disease. Ecol Lett 2017; 20:184-193. [DOI: 10.1111/ele.12720] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/06/2016] [Accepted: 11/17/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Jeremy M. Cohen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Erin L. Sauer
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - David J. Civitello
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | | | - Jason R. Rohr
- Department of Integrative Biology University of South Florida Tampa FL USA
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169
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Gervasi SS, Stephens PR, Hua J, Searle CL, Xie GY, Urbina J, Olson DH, Bancroft BA, Weis V, Hammond JI, Relyea RA, Blaustein AR. Linking Ecology and Epidemiology to Understand Predictors of Multi-Host Responses to an Emerging Pathogen, the Amphibian Chytrid Fungus. PLoS One 2017; 12:e0167882. [PMID: 28095428 PMCID: PMC5240985 DOI: 10.1371/journal.pone.0167882] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 11/22/2016] [Indexed: 12/12/2022] Open
Abstract
Variation in host responses to pathogens can have cascading effects on populations and communities when some individuals or groups of individuals display disproportionate vulnerability to infection or differ in their competence to transmit infection. The fungal pathogen, Batrachochytrium dendrobatidis (Bd) has been detected in almost 700 different amphibian species and is implicated in numerous global amphibian population declines. Identifying key hosts in the amphibian-Bd system–those who are at greatest risk or who pose the greatest risk for others–is challenging due in part to many extrinsic environmental factors driving spatiotemporal Bd distribution and context-dependent host responses to Bd in the wild. One way to improve predictive risk models and generate testable mechanistic hypotheses about vulnerability is to complement what we know about the spatial epidemiology of Bd with data collected through comparative experimental studies. We used standardized pathogen challenges to quantify amphibian survival and infection trajectories across 20 post-metamorphic North American species raised from eggs. We then incorporated trait-based models to investigate the predictive power of phylogenetic history, habitat use, and ecological and life history traits in explaining responses to Bd. True frogs (Ranidae) displayed the lowest infection intensities, whereas toads (Bufonidae) generally displayed the greatest levels of mortality after Bd exposure. Affiliation with ephemeral aquatic habitat and breadth of habitat use were strong predictors of vulnerability to and intensity of infection and several other traits including body size, lifespan, age at sexual maturity, and geographic range also appeared in top models explaining host responses to Bd. Several of the species examined are highly understudied with respect to Bd such that this study represents the first experimental susceptibility data. Combining insights gained from experimental studies with observations of landscape-level disease prevalence may help explain current and predict future pathogen dynamics in the Bd system.
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Affiliation(s)
- Stephanie S. Gervasi
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Patrick R. Stephens
- Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
| | - Jessica Hua
- Biological Sciences Department, Binghamton University, Binghamton, New York, United States of America
| | - Catherine L. Searle
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Gisselle Yang Xie
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jenny Urbina
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Deanna H. Olson
- United States Forest Service, Pacific Northwest Research Station, Corvallis, Oregon, United States of America
| | - Betsy A. Bancroft
- Biology Department, Gonzaga University, Spokane, Washington, United States of America
| | - Virginia Weis
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - John I. Hammond
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Rick A. Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, United States of America
| | - Andrew R. Blaustein
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
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170
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First in Vivo Batrachochytrium dendrobatidis Transcriptomes Reveal Mechanisms of Host Exploitation, Host-Specific Gene Expression, and Expressed Genotype Shifts. G3-GENES GENOMES GENETICS 2017; 7:269-278. [PMID: 27856699 PMCID: PMC5217115 DOI: 10.1534/g3.116.035873] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For generalist pathogens, host species represent distinct selective environments, providing unique challenges for resource acquisition and defense from host immunity, potentially resulting in host-dependent differences in pathogen fitness. Gene expression modulation should be advantageous, responding optimally to a given host and mitigating the costs of generalism. Batrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians, shows variability in pathogenicity among isolates, and within-strain virulence changes rapidly during serial passages through artificial culture. For the first time, we characterize the transcriptomic profile of Bd in vivo, using laser-capture microdissection. Comparison of Bd transcriptomes (strain JEL423) in culture and in two hosts (Atelopus zeteki and Hylomantis lemur), reveals >2000 differentially expressed genes that likely include key Bd defense and host exploitation mechanisms. Variation in Bd transcriptomes from different amphibian hosts demonstrates shifts in pathogen resource allocation. Furthermore, expressed genotype variant frequencies of Bd populations differ between culture and amphibian skin, and among host species, revealing potential mechanisms underlying rapid changes in virulence and the possibility that amphibian community composition shapes Bd evolutionary trajectories. Our results provide new insights into how changes in gene expression and infecting population genotypes can be key to the success of a generalist fungal pathogen.
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171
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Jones DK, Dang TD, Urbina J, Bendis RJ, Buck JC, Cothran RD, Blaustein AR, Relyea RA. Effect of Simultaneous Amphibian Exposure to Pesticides and an Emerging Fungal Pathogen, Batrachochytrium dendrobatidis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:671-679. [PMID: 28001054 DOI: 10.1021/acs.est.6b06055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Amphibian declines have been linked to numerous factors, including pesticide use and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Moreover, research has suggested a link between amphibian sensitivity to Bd and pesticide exposure. We simultaneously exposed postmetamorphic American toads (Anaxyrus americanus), western toads (A. boreas), spring peepers (Pseudacris crucifer), Pacific treefrogs (P. regilla), leopard frogs (Lithobates pipiens), and Cascades frogs (Rana cascadae) to a factorial combination of two pathogen treatments (Bd+, Bd-) and four pesticide treatments (control, ethanol vehicle, herbicide mixture, and insecticide mixture) for 14 d to quantify survival and infection load. We found no interactive effects of pesticides and Bd on anuran survival and no effects of pesticides on infection load. Mortality following Bd exposure increased in spring peepers and American toads and was dependent upon snout-vent length in western toads, American toads, and Pacific treefrogs. Previous studies reported effects of early sublethal pesticide exposure on amphibian Bd sensitivity and infection load at later life stages, but we found simultaneous exposure to sublethal pesticide concentrations and Bd had no such effect on postmetamorphic juvenile anurans. Future research investigating complex interactions between pesticides and Bd should employ a variety of pesticide formulations and Bd strains and follow the effects of exposure throughout ontogeny.
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Affiliation(s)
- Devin K Jones
- Department of Biological Sciences, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | | | | | - Randall J Bendis
- Department of Biological Sciences, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Julia C Buck
- Marine Science Institute, University of California Santa Barbara , Santa Barbara, California 93106, United States
| | - Rickey D Cothran
- Department of Biological Sciences, Southwestern Oklahoma State University , Weatherford, Oklahoma 73096, United States
| | | | - Rick A Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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172
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Hassell JM, Begon M, Ward MJ, Fèvre EM. Urbanization and Disease Emergence: Dynamics at the Wildlife-Livestock-Human Interface. Trends Ecol Evol 2017; 32:55-67. [PMID: 28029378 PMCID: PMC5214842 DOI: 10.1016/j.tree.2016.09.012] [Citation(s) in RCA: 324] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 12/22/2022]
Abstract
Urbanization is characterized by rapid intensification of agriculture, socioeconomic change, and ecological fragmentation, which can have profound impacts on the epidemiology of infectious disease. Here, we review current scientific evidence for the drivers and epidemiology of emerging wildlife-borne zoonoses in urban landscapes, where anthropogenic pressures can create diverse wildlife-livestock-human interfaces. We argue that these interfaces represent a critical point for cross-species transmission and emergence of pathogens into new host populations, and thus understanding their form and function is necessary to identify suitable interventions to mitigate the risk of disease emergence. To achieve this, interfaces must be studied as complex, multihost communities whose structure and form are dictated by both ecological and anthropological factors.
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Affiliation(s)
- James M Hassell
- Institute of Infection and Global Health, The University of Liverpool, Leahurst Campus, Chester High Road, Neston, CH64 7TE, UK; International Livestock Research Institute, Nairobi, Kenya
| | - Michael Begon
- Institute of Integrative Biology, The University of Liverpool, Liverpool L69 7ZB, UK
| | - Melissa J Ward
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, UK
| | - Eric M Fèvre
- Institute of Infection and Global Health, The University of Liverpool, Leahurst Campus, Chester High Road, Neston, CH64 7TE, UK; International Livestock Research Institute, Nairobi, Kenya.
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173
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Sabino-Pinto J, Bletz M, Iturriaga M, Vences M, Rodríguez A. Low infection prevalence of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Chytridiomycetes: Rhizophydiales) in Cuba. AMPHIBIA-REPTILIA 2017. [DOI: 10.1163/15685381-00003100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The chytrid fungus Batrachochytrium dendrobatidis (Bd) is responsible for population declines and extinctions of amphibians worldwide. The distribution and prevalence of Bd in Cuba has remained unknown to date, with only a single report on its presence. We collected 182 samples from wild anuran populations across 21 species and 16 localities and tested for the presence of Bd using qPCRs. Only six Bd positive samples from four species were detected in three very close localities in Central Cuba. Bd prevalence was of 10-20% in the positive localities, and the island-wide prevalence was only 3.2%. These results indicate that Bd occurrence in Cuba might be concentrated in or even restricted to the central Guamuhaya Massif and call for increased conservation and monitoring efforts in these mountains along with additional sampling in areas and species not covered in this study.
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Affiliation(s)
- Joana Sabino-Pinto
- Zoological Institute, Technical University of Braunschweig, Mendelssohnstr. 4, 38106 Braunschweig, Germany
| | - Molly C. Bletz
- Zoological Institute, Technical University of Braunschweig, Mendelssohnstr. 4, 38106 Braunschweig, Germany
| | - Manuel Iturriaga
- División de Colecciones Zoológicas, Instituto de Ecología y Sistemática, Cta. Varona 11835 e/ Oriente y Lindero, Reparto Parajón, Boyeros, 11900 La Habana, Cuba
| | - Miguel Vences
- Zoological Institute, Technical University of Braunschweig, Mendelssohnstr. 4, 38106 Braunschweig, Germany
| | - Ariel Rodríguez
- Zoological Institute, Technical University of Braunschweig, Mendelssohnstr. 4, 38106 Braunschweig, Germany
- Zoological Institute, University of Veterinary Medicine (TiHo) Hannover, Bünteweg 17, 30559 Hannover, Germany
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174
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Rollins-Smith LA. Amphibian immunity-stress, disease, and climate change. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 66:111-119. [PMID: 27387153 DOI: 10.1016/j.dci.2016.07.002] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 06/25/2016] [Accepted: 07/01/2016] [Indexed: 05/22/2023]
Abstract
Like all other vertebrate groups, amphibian responses to the environment are mediated through the brain (hypothalamic)-pituitary-adrenal/interrenal (HPA/I) axis and the sympathetic nervous system. Amphibians are facing historically unprecedented environmental stress due to climate change that will involve unpredictable temperature and rainfall regimes and possible nutritional deficits due to extremes of temperature and drought. At the same time, amphibians in all parts of the world are experiencing unprecedented declines due to the emerging diseases, chytridiomycosis (caused by Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans) and ranavirus diseases due to viruses of the genus Ranavirus in the family Iridoviridae. Other pathogens and parasites also afflict amphibians, but here I will limit myself to a review of recent literature linking stress and these emerging diseases (chytridiomycosis and ranavirus disease) in order to better predict how environmental stressors and disease will affect global amphibian populations.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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175
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Hunter ME, Dorazio RM, Butterfield JSS, Meigs‐Friend G, Nico LG, Ferrante JA. Detection limits of quantitative and digital
PCR
assays and their influence in presence–absence surveys of environmental
DNA. Mol Ecol Resour 2016; 17:221-229. [DOI: 10.1111/1755-0998.12619] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/31/2016] [Accepted: 09/19/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Margaret E. Hunter
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
| | - Robert M. Dorazio
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
| | - John S. S. Butterfield
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
| | - Gaia Meigs‐Friend
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
| | - Leo G. Nico
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
| | - Jason A. Ferrante
- U.S. Geological Survey Wetland and Aquatic Research Center 7920 NW 71st Street Gainesville FL 32653 USA
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176
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Ruano-Fajardo G, Toledo LF, Mott T. Jumping into a trap: high prevalence of chytrid fungus in the preferred microhabitats of a bromeliad-specialist frog. DISEASES OF AQUATIC ORGANISMS 2016; 121:223-232. [PMID: 27786160 DOI: 10.3354/dao03045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been identified as a major threat to several amphibian populations in tropical forests. Amphibians that inhabit the phytotelmata (water tanks) of bromeliads may be especially at risk of Bd infection since the humid, environmentally buffered microhabitat that they prefer might also be favorable for Bd persistence on the host. To test this hypothesis, we sampled adults and tadpoles of the bromeligenous anuran Phyllodytes edelmoi (endemic to the northern Brazilian Atlantic Forest) from the bromeliad Portea leptantha for Bd, using qPCR. We also analyzed 8 bromeliad characteristics: water tank temperature and pH, canopy closure, tank diameter, number of leaves, bromeliad maximum column depth to store water, bromeliad relative volume, and season. Adult frogs preferentially selected bromeliads with a smaller diameter, more leaves and a relatively higher volume of water. We found that Bd was more prevalent in frogs inhabiting bromeliad phytotelmata with smaller diameters, suggesting that the behavioral preferences of P. edelmoi may be driving Bd infection patterns. Therefore, species such as P. edelmoi will be trapped by their own natural history traits.
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Affiliation(s)
- Gustavo Ruano-Fajardo
- Programa de Pós Graduação em Diversidade Biológica e Conservação nos Trópicos, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Tabuleiro, 57052-970 Maceió, Alagoas, Brazil
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177
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Julian JT, Gould VA, Glenney GW, Brooks RP. Seasonal infection rates of Batrachochytrium dendrobatidis in populations of northern green frog Lithobates clamitans melanota tadpoles. DISEASES OF AQUATIC ORGANISMS 2016; 121:97-104. [PMID: 27667807 DOI: 10.3354/dao03046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Few studies have documented seasonal variation of Batrachochytrium dendrobatidis (Bd) infection rates in larval amphibians. We identified 4 natural populations of northern green frogs Lithobates clamitans melanota in Pennsylvania (USA) that contained Bd-infected tadpoles during post-wintering collections in May and June, after hibernating tadpoles had overwintered in wetlands. However, we failed to detect infected tadpoles at those wetlands when pre-wintering collections were made in late July through early September. We observed 2 cohorts of tadpoles that appeared to lack Bd-infected individuals in pre-wintering collections, yet contained Bd-infected individuals the following spring. We also observed 4 cohorts of pre-wintering tadpoles that were Bd-free, even though post-wintering tadpoles collected earlier in the year were infected with Bd. Our results suggest that tadpoles either reduce Bd infections during the summer months, and/or infections proliferate sometime prior to (or shortly after) tadpoles emerge from hibernation. It is unlikely that pre-wintering tadpoles were too small to detect Bd zoospores because (1) there was no correlation between Bd zoospore levels and tadpole size or stage, and (2) size was not a significant predictor of infection status. These results suggest that, while sampling larvae can be an effective means of collecting large sample sizes, investigators in our Mid-Atlantic region should conduct sampling by early summer to maximize the chances of detecting Bd. Further research is warranted to determine whether wetland topography and warm, shallow microhabitats within wetlands contribute to a population's ability to drastically reduce Bd prevalence prior to overwintering at ponds.
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Affiliation(s)
- James T Julian
- Division of Mathematics and Natural Science, Penn State University-Altoona College, 3000 Ivyside Park, Altoona, PA 16601,USA
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178
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Fontenot CL, Pojman JA. Self and Conspecific Dermatophagy in the Aquatic Salamander Amphiuma tridactylum. SOUTHEAST NAT 2016. [DOI: 10.1656/058.015.0312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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179
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Nowakowski AJ, Whitfield SM, Eskew EA, Thompson ME, Rose JP, Caraballo BL, Kerby JL, Donnelly MA, Todd BD. Infection risk decreases with increasing mismatch in host and pathogen environmental tolerances. Ecol Lett 2016; 19:1051-61. [PMID: 27339786 DOI: 10.1111/ele.12641] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/07/2016] [Accepted: 05/23/2016] [Indexed: 01/14/2023]
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) has caused the greatest known wildlife pandemic, infecting over 500 amphibian species. It remains unclear why some host species decline from disease-related mortality whereas others persist. We introduce a conceptual model that predicts that infection risk in ectotherms will decrease as the difference between host and pathogen environmental tolerances (i.e. tolerance mismatch) increases. We test this prediction using both local-scale data from Costa Rica and global analyses of over 11 000 Bd infection assays. We find that infection prevalence decreases with increasing thermal tolerance mismatch and with increasing host tolerance of habitat modification. The relationship between environmental tolerance mismatches and Bd infection prevalence is generalisable across multiple amphibian families and spatial scales, and the magnitude of the tolerance mismatch effect depends on environmental context. These findings may help explain patterns of amphibian declines driven by a global wildlife pandemic.
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Affiliation(s)
- A Justin Nowakowski
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA, 95616, USA
| | | | - Evan A Eskew
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA, 95616, USA
| | - Michelle E Thompson
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Jonathan P Rose
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA, 95616, USA
| | - Benjamin L Caraballo
- Science Department, Renaissance Charter High School for Innovation, 410 E. 100 St., New York, NY, 10029, USA
| | - Jacob L Kerby
- Biology Department, University of South Dakota, 414 E. Clark St., Vermillion, SD, 57069, USA
| | - Maureen A Donnelly
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Brian D Todd
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA, 95616, USA
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180
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Love CN, Winzeler ME, Beasley R, Scott DE, Nunziata SO, Lance SL. Patterns of amphibian infection prevalence across wetlands on the Savannah River Site, South Carolina, USA. DISEASES OF AQUATIC ORGANISMS 2016; 121:1-14. [PMID: 27596855 DOI: 10.3354/dao03039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Amphibian diseases, such as chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) and ranaviral disease caused by ranaviruses, are often linked to global amphibian population declines, yet the ecological dynamics of both pathogens are poorly understood. The goal of our study was to determine the baseline prevalence, pathogen loads, and co-infection rate of Bd and ranavirus across the Savannah River Site (SRS) in South Carolina, USA, a region with rich amphibian diversity and a history of amphibian-based research. We tested over 1000 individuals, encompassing 21 amphibian species from 11 wetlands for both Bd and ranavirus. The prevalence of Bd across individuals was 9.7%. Using wetland means, the mean (±SE) Bd prevalence was 7.9 ± 2.9%. Among toad species, Anaxyrus terrestris had 95 and 380% greater odds of being infected with Bd than Scaphiopus holbrookii and Gastrophryne carolinensis, respectively. Odds of Bd infection in adult A. terrestris and Lithobates sphenocephalus were 75 to 77% greater in metal-contaminated sites. The prevalence of ranavirus infections across all individuals was 37.4%. Mean wetland ranavirus prevalence was 29.8 ± 8.8% and was higher in post-metamorphic individuals than in aquatic larvae. Ambystoma tigrinum had 83 to 85% higher odds of ranavirus infection than A. opacum and A. talpoideum. We detected a 4.8% co-infection rate, with individuals positive for ranavirus having a 5% higher occurrence of Bd. In adult Anaxyrus terrestris, odds of Bd infection were 13% higher in ranavirus-positive animals and odds of co-infection were 23% higher in contaminated wetlands. Overall, we found the pathogen prevalence varied by wetland, species, and life stage.
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Affiliation(s)
- Cara N Love
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina 29802, USA
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181
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Rethinking the role of invertebrate hosts in the life cycle of the amphibian chytridiomycosis pathogen. Parasitology 2016; 143:1723-1729. [PMID: 27573338 DOI: 10.1017/s0031182016001360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The amphibian pathogen Batrachochytrium dendrobatidis (Bd) has recently emerged as a primary factor behind declining global amphibian populations. Much about the basic biology of the pathogen is unknown, however, such as its true ecological niche and life cycle. Here we evaluated invertebrates as infection models by inoculating host species that had previously been suggested to be parasitized in laboratory settings: crayfish (Procambarus alleni) and nematodes (Caenorhabditis elegans). We found neither negative effects on either host nor evidence of persistent infection despite using higher inoculum loads and more pathogen genotypes than tested in previous studies. In contrast, addition of Bd to C. elegans cultures had a slight positive effect on host growth. Bd DNA was detected on the carapace of 2/34 crayfish 7 weeks post-inoculation, suggesting some means of persistence in the mesocosm. These results question the role of invertebrates as alternative hosts of Bd and their ability to modulate disease dynamics.
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182
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Biega A, Greenberg DA, Mooers AO, Jones OR, Martin TE. Global representation of threatened amphibiansex situis bolstered by non-traditional institutions, but gaps remain. Anim Conserv 2016. [DOI: 10.1111/acv.12297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. Biega
- Department of Biological Sciences and IRMACS; Simon Fraser University; Burnaby BC Canada
| | - D. A. Greenberg
- Department of Biological Sciences and IRMACS; Simon Fraser University; Burnaby BC Canada
| | - A. O. Mooers
- Department of Biological Sciences and IRMACS; Simon Fraser University; Burnaby BC Canada
| | - O. R. Jones
- Department of Biology & Max-Planck Odense Center on the Biodemography of Aging; University of Southern Denmark; Odense Denmark
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183
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Scheele BC, Hunter DA, Banks SC, Pierson JC, Skerratt LF, Webb R, Driscoll DA. High adult mortality in disease‐challenged frog populations increases vulnerability to drought. J Anim Ecol 2016; 85:1453-1460. [DOI: 10.1111/1365-2656.12569] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/21/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Ben C. Scheele
- Fenner School of Environment and Society College of Medicine Biology and Environment Australian National University Canberra ACT 0200 Australia
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University 1 James Cook Drive Townsville City QLD 4811 Australia
| | - David A. Hunter
- NSW Office of Environment and Heritage PO Box 544 Albury NSW 2640 Australia
| | - Sam C. Banks
- Fenner School of Environment and Society College of Medicine Biology and Environment Australian National University Canberra ACT 0200 Australia
| | - Jennifer C. Pierson
- Fenner School of Environment and Society College of Medicine Biology and Environment Australian National University Canberra ACT 0200 Australia
| | - Lee F. Skerratt
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University 1 James Cook Drive Townsville City QLD 4811 Australia
| | - Rebecca Webb
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University 1 James Cook Drive Townsville City QLD 4811 Australia
| | - Don A. Driscoll
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Burwood Vic 3125 Australia
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184
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Projecting the Global Distribution of the Emerging Amphibian Fungal Pathogen, Batrachochytrium dendrobatidis, Based on IPCC Climate Futures. PLoS One 2016; 11:e0160746. [PMID: 27513565 PMCID: PMC4981458 DOI: 10.1371/journal.pone.0160746] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 07/25/2016] [Indexed: 11/19/2022] Open
Abstract
Projected changes in climate conditions are emerging as significant risk factors to numerous species, affecting habitat conditions and community interactions. Projections suggest species range shifts in response to climate change modifying environmental suitability and is supported by observational evidence. Both pathogens and their hosts can shift ranges with climate change. We consider how climate change may influence the distribution of the emerging infectious amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), a pathogen associated with worldwide amphibian population losses. Using an expanded global Bd database and a novel modeling approach, we examined a broad set of climate metrics to model the Bd-climate niche globally and regionally, then project how climate change may influence Bd distributions. Previous research showed that Bd distribution is dependent on climatic variables, in particular temperature. We trained a machine-learning model (random forest) with the most comprehensive global compilation of Bd sampling records (~5,000 site-level records, mid-2014 summary), including 13 climatic variables. We projected future Bd environmental suitability under IPCC scenarios. The learning model was trained with combined worldwide data (non-region specific) and also separately per region (region-specific). One goal of our study was to estimate of how Bd spatial risks may change under climate change based on the best available data. Our models supported differences in Bd-climate relationships among geographic regions. We projected that Bd ranges will shift into higher latitudes and altitudes due to increased environmental suitability in those regions under predicted climate change. Specifically, our model showed a broad expansion of areas environmentally suitable for establishment of Bd on amphibian hosts in the temperate zones of the Northern Hemisphere. Our projections are useful for the development of monitoring designs in these areas, especially for sensitive species and those vulnerable to multiple threats.
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185
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Colston TJ, Jackson CR. Microbiome evolution along divergent branches of the vertebrate tree of life: what is known and unknown. Mol Ecol 2016; 25:3776-800. [DOI: 10.1111/mec.13730] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/25/2016] [Accepted: 05/30/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Timothy J. Colston
- Department of Biology The University of Mississippi University MS 38677 USA
| | - Colin R. Jackson
- Department of Biology The University of Mississippi University MS 38677 USA
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186
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Rodrigues AM, de Hoog GS, de Camargo ZP. Sporothrix Species Causing Outbreaks in Animals and Humans Driven by Animal-Animal Transmission. PLoS Pathog 2016; 12:e1005638. [PMID: 27415796 PMCID: PMC4945023 DOI: 10.1371/journal.ppat.1005638] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Anderson Messias Rodrigues
- Cell Biology Division, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), São Paulo, São Paulo, Brazil
- * E-mail:
| | - G. Sybren de Hoog
- Centraalbureau voor Schimmelcultures, KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Zoilo Pires de Camargo
- Cell Biology Division, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), São Paulo, São Paulo, Brazil
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187
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Petersen CE, Lovich RE, Phillips CA, Dreslik MJ, Lannoo MJ. Prevalence and Seasonality of the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis Along Widely Separated Longitudes Across the United States. ECOHEALTH 2016; 13:368-382. [PMID: 26935823 DOI: 10.1007/s10393-016-1101-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 06/05/2023]
Abstract
The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines on almost all continents. We report on prevalence and intensity of Bd in the United States amphibian populations across three longitudinally separated north-to-south transects conducted at 15 Department of Defense installations during two sampling periods (late-spring/early summer and mid to late summer). Such a standardized approach minimizes the effects of sampling and analytical bias, as well as human disturbance (by sampling restricted military bases), and therefore permits a cleaner interpretation of environmental variables known to affect chytrid dynamics such as season, temperature, rainfall, latitude, and longitude. Our prevalence of positive samples was 20.4% (137/670), and our mean intensity was 3.21 zoospore equivalents (SE = 1.03; range 0.001-103.59). Of the 28 amphibian species sampled, 15 tested positive. Three sites had no evidence of Bd infection; across the remaining 12 Bd-positive sites, neither infection prevalence nor intensity varied systematically. We found a more complicated pattern of Bd prevalence than anticipated. Early season samples showed no trend associated with increasing temperature and precipitation and decreasing (more southerly) latitudes; while in late season samples, the proportion of infected individuals decreased with increasing temperature and precipitation and decreasing latitudes. A similar pattern held for the east-west gradient, with the highest prevalence associated with more easterly/recently warmer sites in the early season then shifting to more westerly/recently cooler sites in the later season. Bd intensity across bases and sampling periods was comparatively low. Some of the trends in our data have been seen in previous studies, and our results offer further continental-level Bd sampling over which more concentrated local sampling efforts can be overlaid.
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Affiliation(s)
- Christopher E Petersen
- Naval Facilities Engineering Command Atlantic, Code EV52CP, 6506 Hampton Blvd., Norfolk, VA, 23508, USA.
| | - Robert E Lovich
- Naval Facilities Engineering Command Southwest, 1220 Pacific Highway, San Diego, CA, 92132, USA
| | - Christopher A Phillips
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
| | - Michael J Dreslik
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
| | - Michael J Lannoo
- Indiana University School of Medicine, Terre Haute, IN, 47802, USA
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188
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Valencia-Aguilar A, Toledo LF, Vital MV, Mott T. Seasonality, Environmental Factors, and Host Behavior Linked to Disease Risk in Stream-Dwelling Tadpoles. HERPETOLOGICA 2016. [DOI: 10.1655/herpetologica-d-15-00013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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189
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Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines. Sci Rep 2016; 6:25625. [PMID: 27212145 PMCID: PMC4876446 DOI: 10.1038/srep25625] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/20/2016] [Indexed: 11/20/2022] Open
Abstract
Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a “smoking gun” was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased local extinction risk, evidence for effects of these drivers is lacking at large spatial scales. Here, we use observations of 389 time-series of 83 species and complexes from 61 study areas across North America to test the effects of 4 of the major hypothesized drivers of declines. While we find that local amphibian populations are being lost from metapopulations at an average rate of 3.79% per year, these declines are not related to any particular threat at the continental scale; likewise the effect of each stressor is variable at regional scales. This result - that exposure to threats varies spatially, and populations vary in their response - provides little generality in the development of conservation strategies. Greater emphasis on local solutions to this globally shared phenomenon is needed.
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190
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CITIZEN SCIENTISTS MONITOR A DEADLY FUNGUS THREATENING AMPHIBIAN COMMUNITIES IN NORTHERN COASTAL CALIFORNIA, USA. J Wildl Dis 2016; 52:516-23. [PMID: 27195681 DOI: 10.7589/2015-10-280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ecoclub youth and supervising family members conducted citizen science to assess regional prevalence and distribution of Batrachochytrium dendrobatidis (Bd) among amphibians at Humboldt Bay National Wildlife Refuge (Refuge) and Redwood National and State Parks (Parks), Humboldt County, California, US, May 2013 through December 2014. Using quantitative real-time PCR, 26 (17%) of 155 samples were positive for Bd. Positive samples occurred in four frog and toad species: foothill yellow-legged frog ( Rana boylii ), northern red-legged frog ( Rana aurora ), Pacific chorus frog ( Pseudacris regilla ), and western toad (Anaxyrus [Bufo] boreas); no salamanders or anuran larvae were positive. Except for R. aurora , all infected anurans were first-time species reports for coastal northern California. At the Refuge, significantly fewer (6/71) postmetamorphic amphibians were positive compared to the Parks (20/69; P=0.0018). We assessed the association of being PCR-positive for Bd, season of sampling, and age of sampler (child, teen, or adult). The full model with season, species, and sampler age had the greatest support. Frogs tested in winter or spring were more likely to be positive than those tested in summer or fall; foothill yellow-legged frogs, northern red-legged frogs, and western toads were more likely to be positive than were Pacific chorus frogs; and the probability of being positive nearly doubled when a child (≤12 yr old) collected the sample compared to a teen or adult. Our results support other chytrid studies that found amphibians are more susceptible to Bd when temperatures are cool and that species differ in their susceptibility. The Ecoclub's findings provide new information important to conservation of northern California's coastal amphibians and demonstrate the value of involving children in citizen science.
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191
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Invasive North American bullfrogs transmit lethal fungus Batrachochytrium dendrobatidis infections to native amphibian host species. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1161-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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192
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Hirschfeld M, Blackburn DC, Doherty-Bone TM, Gonwouo LN, Ghose S, Rödel MO. Dramatic Declines of Montane Frogs in a Central African Biodiversity Hotspot. PLoS One 2016; 11:e0155129. [PMID: 27149624 PMCID: PMC4858272 DOI: 10.1371/journal.pone.0155129] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 04/25/2016] [Indexed: 11/18/2022] Open
Abstract
Amphibian populations are vanishing worldwide. Declines and extinctions of many populations have been attributed to chytridiomycosis, a disease induced by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). In Africa, however, changes in amphibian assemblages were typically attributed to habitat change. We conducted a retrospective study utilizing field surveys from 2004–2012 of the anuran faunas on two mountains in western Cameroon, a hotspot of African amphibian diversity. The number of species detected was negatively influenced by year, habitat degradation, and elevation, and we detected a decline of certain species. Because another study in this region revealed an emergence of Bd in 2008, we screened additional recent field-collected samples and also pre-decline preserved museum specimens for the presence of Bd supporting emergence before 2008. When comparing the years before and after Bd detection, we found significantly diminished frog species richness and abundance on both mountains after Bd emergence. Our analyses suggest that this may be the first disease-driven community-level decline in anuran biodiversity in Central Africa. The disappearance of several species known to tolerate habitat degradation, and a trend of stronger declines at higher elevations, are consistent with Bd-induced declines in other regions. Not all species decreased; populations of some species remained constant, and others increased after the emergence of Bd. This variation might be explained by species-specific differences in infection probability. Increased habitat protection and Bd-mitigation strategies are needed for sustaining diverse amphibian communities such as those on Mt. Manengouba, which contains nearly half of Cameroon’s frog diversity.
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Affiliation(s)
- Mareike Hirschfeld
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
- * E-mail:
| | - David C. Blackburn
- Department of Herpetology, California Academy of Sciences, San Francisco, California 94118, United States of America
| | - Thomas M. Doherty-Bone
- Conservation Research & Action for Amphibians of Cameroon, Royal Zoological Society of Scotland, Edinburgh Zoo, Edinburgh, United Kingdom
| | - LeGrand Nono Gonwouo
- Cameroon Herpetology-Conservation Biology Foundation (CAMHERP-CBF), PO Box 8218, Yaoundé, Cameroon
| | - Sonia Ghose
- Department of Herpetology, California Academy of Sciences, San Francisco, California 94118, United States of America
| | - Mark-Oliver Rödel
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
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193
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Hartigan A, Wilkinson M, Gower DJ, Streicher JW, Holzer AS, Okamura B. Myxozoan infections of caecilians demonstrate broad host specificity and indicate a link with human activity. Int J Parasitol 2016; 46:375-81. [DOI: 10.1016/j.ijpara.2016.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 11/24/2022]
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194
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195
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Preuss JF, Lambertini C, Leite DDS, Toledo LF, Lucas EM. Crossing the threshold: an amphibian assemblage highly infected withBatrachochytrium dendrobatidisin the southern Brazilian Atlantic forest. STUDIES ON NEOTROPICAL FAUNA AND ENVIRONMENT 2016. [DOI: 10.1080/01650521.2016.1163857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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196
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Zhu W, Fan L, Soto-Azat C, Yan S, Gao X, Liu X, Wang S, Liu C, Yang X, Li Y. Filling a gap in the distribution of Batrachochytrium dendrobatidis: evidence in amphibians from northern China. DISEASES OF AQUATIC ORGANISMS 2016; 118:259-265. [PMID: 27025313 DOI: 10.3354/dao02975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) has been recognized as a major driver of amphibian declines worldwide. Central and northern Asia remain as the greatest gap in the knowledge of the global distribution of Bd. In China, Bd has recently been recorded from south and central regions, but areas in the north remain poorly surveyed. In addition, a recent increase in amphibian farming and trade has put this region at high risk for Bd introduction. To investigate this, we collected a total of 1284 non-invasive skin swabs from wild and captive anurans and caudates, including free-ranging, farmed, ornamental, and museum-preserved amphibians. Bd was detected at low prevalence (1.1%, 12 of 1073) in live wild amphibians, representing the first report of Bd infecting anurans from remote areas of northwestern China. We were unable to obtain evidence of the historical presence of Bd from museum amphibians (n = 72). Alarmingly, Bd was not detected in wild amphibians from the provinces of northeastern China (>700 individuals tested), but was widely present (15.1%, 21 of 139) in amphibians traded in this region. We suggest that urgent implementation of measures is required to reduce the possibility of further spread or inadvertent introduction of Bd to China. It is unknown whether Bd in northern China belongs to endemic and/or exotic genotypes, and this should be the focus of future research.
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Affiliation(s)
- Wei Zhu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
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197
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Susceptibility to disease varies with ontogeny and immunocompetence in a threatened amphibian. Oecologia 2016; 181:997-1009. [DOI: 10.1007/s00442-016-3607-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
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198
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Jenkinson TS, Betancourt Román CM, Lambertini C, Valencia‐Aguilar A, Rodriguez D, Nunes‐de‐Almeida CHL, Ruggeri J, Belasen AM, Silva Leite D, Zamudio KR, Longcore JE, Toledo LF, James TY. Amphibian‐killing chytrid in
B
razil comprises both locally endemic and globally expanding populations. Mol Ecol 2016; 25:2978-96. [DOI: 10.1111/mec.13599] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 02/16/2016] [Accepted: 02/23/2016] [Indexed: 01/13/2023]
Affiliation(s)
- T. S. Jenkinson
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor MI 48109 USA
| | - C. M. Betancourt Román
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor MI 48109 USA
| | - C. Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Campinas SP 13083‐862 Brasil
| | - A. Valencia‐Aguilar
- Programa de Pós‐Graduação em Diversidade Biológica e Conservação nos Trópicos Instituto de Ciências Biológicas e da Saúde Universidade Federal de Alagoas Maceió AL 57052‐970 Brasil
| | - D. Rodriguez
- Department of Biology Texas State University San Marcos TX 78666 USA
| | - C. H. L. Nunes‐de‐Almeida
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Campinas SP 13083‐862 Brasil
| | - J. Ruggeri
- Laboratório de Anfíbios e Répteis Departamento de Zoologia Instituto de Biologia Universidade Federal do Rio de Janeiro Rio de Janeiro RJ 21941‐902 Brasil
| | - A. M. Belasen
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor MI 48109 USA
| | - D. Silva Leite
- Laboratório de Antígenos Bacterianos Departamento de Genética, Evolução e Bioagentes Instituto de Biologia Universidade Estadual de Campinas Campinas SP 13083‐862 Brasil
| | - K. R. Zamudio
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY 14853 USA
| | - J. E. Longcore
- School of Biology and Ecology University of Maine Orono ME 04469 USA
| | - L. F. Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Campinas SP 13083‐862 Brasil
| | - T. Y. James
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor MI 48109 USA
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199
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Brinkman LC, Ray JM, Mathis A, Greene BD. Filling in the Gaps: Natural History and Conservation of Bolitoglossine Salamanders in Central Panama. COPEIA 2016. [DOI: 10.1643/ce-14-213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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200
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Temperature treatments boost subclinical infections of Batrachochytrium dendrobatidis in a Mexican salamander (Pseudoeurycea leprosa). REV MEX BIODIVERS 2016. [DOI: 10.1016/j.rmb.2016.01.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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