1
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Carvalho T, Medina D, P Ribeiro L, Rodriguez D, Jenkinson TS, Becker CG, Toledo LF, Hite JL. Coinfection with chytrid genotypes drives divergent infection dynamics reflecting regional distribution patterns. Commun Biol 2023; 6:941. [PMID: 37709833 PMCID: PMC10502024 DOI: 10.1038/s42003-023-05314-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
By altering the abundance, diversity, and distribution of species-and their pathogens-globalization may inadvertently select for more virulent pathogens. In Brazil's Atlantic Forest, a hotspot of amphibian biodiversity, the global amphibian trade has facilitated the co-occurrence of previously isolated enzootic and panzootic lineages of the pathogenic amphibian-chytrid (Batrachochytrium dendrobatidis, 'Bd') and generated new virulent recombinant genotypes ('hybrids'). Epidemiological data indicate that amphibian declines are most severe in hybrid zones, suggesting that coinfections are causing more severe infections or selecting for higher virulence. We investigated how coinfections involving these genotypes shapes virulence and transmission. Overall, coinfection favored the more virulent and competitively superior panzootic genotype, despite dampening its transmission potential and overall virulence. However, for the least virulent and least competitive genotype, coinfection increased both overall virulence and transmission. Thus, by integrating experimental and epidemiological data, our results provide mechanistic insight into how globalization can select for, and propel, the emergence of introduced hypervirulent lineages, such as the globally distributed panzootic lineage of Bd.
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Affiliation(s)
- Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, São Paulo, Brazil.
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Daniel Medina
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, São Paulo, Brazil
- Sistema Nacional de Investigación, SENACYT, Building 205, City of Knowledge, Clayton, Panama, Republic of Panama
- Department of Biology, and Center for Infectious Disease Dynamics, One Health Microbiome Center, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Luisa P Ribeiro
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, São Paulo, Brazil
| | - David Rodriguez
- Department of Biology, Texas State University, San Marcos, TX, 78666, USA
| | - Thomas S Jenkinson
- Department of Biological Sciences, California State University-East Bay, Hayward, CA, 94542, USA
| | - C Guilherme Becker
- Department of Biology, and Center for Infectious Disease Dynamics, One Health Microbiome Center, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, São Paulo, Brazil
| | - Jessica L Hite
- School of Veterinary Medicine, Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
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2
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Rawien J, Jairam-Doerga S. Predicted Batrachochytrium dendrobatidis infection sites in Guyana, Suriname, and French Guiana using the species distribution model maxent. PLoS One 2022; 17:e0270134. [PMID: 35834475 PMCID: PMC9282542 DOI: 10.1371/journal.pone.0270134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 06/03/2022] [Indexed: 11/19/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) which causes that amphibian disease chytridiomycosis is expanding its worldwide range from an Asian origin, infecting amphibians in a growing number of countries. Modelling the potential range of this amphibian pathogen using environmental variables and presence data could advance our understanding of at-risk areas and species in locations with limited surveillance to date. We used a species distribution model to assess Bd habitat suitability in the three Guiana's (Guyana, Suriname, and French Guiana) in South America. The model output showed that all three countries have substantial areas where Bd could grow and proliferate, and maximum temperature of the warmest month was the top predictor of suitable Bd habitat, inversely correlated with modeled Bd occurrence. Predicted Bd infection areas in Guyana and French Guiana were large and localized whereas possible sites in Suriname were more scattered throughout the country. The areas projected as potential suitable in Suriname were mostly high elevation regions. These results could help inform efficiencies for development of a proactive monitoring program that could alert managers of novel Bd outbreaks for focused mitigation actions to forestall the spread of this amphibian disease.
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Affiliation(s)
- Jairam Rawien
- Anton de Kom University of Suriname, National Zoological Collection Suriname, Paramaribo, Suriname
| | - Sabitrie Jairam-Doerga
- Anton de Kom University of Suriname, National Herbarium of Suriname, Paramaribo, Suriname
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3
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Alvarado-Rybak M, Acuña P, Peñafiel-Ricaurte A, Sewell TR, O'Hanlon SJ, Fisher MC, Valenzuela-Sánchez A, Cunningham AA, Azat C. Chytridiomycosis Outbreak in a Chilean Giant Frog ( Calyptocephalella gayi) Captive Breeding Program: Genomic Characterization and Pathological Findings. Front Vet Sci 2021; 8:733357. [PMID: 34631859 PMCID: PMC8497818 DOI: 10.3389/fvets.2021.733357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
Emerging infectious diseases in wildlife are increasingly associated with animal mortality and species declines, but their source and genetic characterization often remains elusive. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions at the global scale. We used histology and whole-genome sequencing to describe the lesions caused by, and the genetic variability of, two Bd isolates obtained from a mass mortality event in a captive population of the threatened Chilean giant frog (Calyptocephalella gayi). This was the first time an association between Bd and high mortality had been detected in this charismatic and declining frog species. Pathological examinations revealed that 30 dead metamorphosed frogs presented agnathia or brachygnathia, a condition that is reported for the first time in association with chytridiomycosis. Phylogenomic analyses revealed that Bd isolates (PA1 and PA2) from captive C. gayi group with other Bd isolates (AVS2, AVS4, and AVS7) forming a single highly supported Chilean Bd clade within the global panzootic lineage of Bd (BdGPL). These findings are important to inform the strengthening of biosecurity measures to prevent the impacts of chytridiomycosis in captive breeding programs elsewhere.
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Affiliation(s)
- Mario Alvarado-Rybak
- Sustainability Research Centre & PhD Program in Conservation Medicine, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, United Kingdom.,Núcleo de Ciencias Aplicadas en Ciencias Veterinarias y Agronómicas, Universidad de las Américas, Santiago, Chile
| | - Paz Acuña
- Criadero y Centro de Exhibición de la Rana Chilena Calyptocephalella gayi, Santiago, Chile
| | - Alexandra Peñafiel-Ricaurte
- Sustainability Research Centre & PhD Program in Conservation Medicine, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Thomas R Sewell
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Simon J O'Hanlon
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Andres Valenzuela-Sánchez
- Sustainability Research Centre & PhD Program in Conservation Medicine, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.,ONG Ranita de Darwin, Valdivia, Chile.,Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
| | | | - Claudio Azat
- Sustainability Research Centre & PhD Program in Conservation Medicine, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
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4
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Waddle AW, Rivera R, Rice H, Keenan EC, Rezaei G, Levy JE, Vasquez YS, Sai M, Hill J, Zmuda A, Lambreghts Y, Jaeger JR. Amphibian resistance to chytridiomycosis increases following low‐virulence chytrid fungal infection or drug‐mediated clearance. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.13974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Anthony W. Waddle
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
- One Health Research Group Faculty of Veterinary and Agricultural Sciences University of Melbourne Werribee Vic. Australia
| | - Rebeca Rivera
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Hannah Rice
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Emma C. Keenan
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Ghazal Rezaei
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Joshua E. Levy
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Yesenia S. Vasquez
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Marlai Sai
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Jessica Hill
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Alexandra Zmuda
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
| | - Yorick Lambreghts
- School of Biological Sciences University of Tasmania Hobart TAS Australia
| | - Jef R. Jaeger
- School of Life Sciences University of Nevada, Las Vegas Las Vegas NV USA
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5
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Basanta MD, Byrne AQ, Rosenblum EB, Piovia-Scott J, Parra-Olea G. Early presence of Batrachochytrium dendrobatidis in Mexico with a contemporary dominance of the global panzootic lineage. Mol Ecol 2020; 30:424-437. [PMID: 33205419 DOI: 10.1111/mec.15733] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/26/2020] [Accepted: 11/11/2020] [Indexed: 01/13/2023]
Abstract
Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a devastating infectious disease of amphibians. Retrospective studies using museum vouchers and genetic samples supported the hypothesis that Bd colonized Mexico from North America and then continued to spread into Central and South America, where it led to dramatic losses in tropical amphibian biodiversity (the epizootic wave hypothesis). While these studies suggest that Bd has been in Mexico since the 1970s, information regarding the historical and contemporary occurrence of different pathogen genetic lineages across the country is limited. In the current study, we investigated the historical and contemporary patterns of Bd in Mexico. We combined the swabbing of historical museum vouchers and sampling of wild amphibians with a custom Bd genotyping assay to assess the presence, prevalence, and genetic diversity of Bd over time in Mexico. We found Bd-positive museum specimens from the late 1800s, far earlier than previous records and well before recent amphibian declines. With Bd genotypes from samples collected between 1975-2019, we observed a contemporary dominance of the global panzootic lineage in Mexico and report four genetic subpopulations and potential for admixture among these populations. The observed genetic variation did not have a clear geographic signature or provide clear support for the epizootic wave hypothesis. These results provide a framework for testing new questions regarding Bd invasions and their temporal relationship to observed amphibian declines in the Americas.
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Affiliation(s)
- M Delia Basanta
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México.,Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Allison Q Byrne
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - Jonah Piovia-Scott
- School of Biological Sciences, Washington State University, Vancouver, BC, USA
| | - Gabriela Parra-Olea
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México
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6
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Brannelly LA, McCallum HI, Grogan LF, Briggs CJ, Ribas MP, Hollanders M, Sasso T, Familiar López M, Newell DA, Kilpatrick AM. Mechanisms underlying host persistence following amphibian disease emergence determine appropriate management strategies. Ecol Lett 2020; 24:130-148. [PMID: 33067922 DOI: 10.1111/ele.13621] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/18/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022]
Abstract
Emerging infectious diseases have caused many species declines, changes in communities and even extinctions. There are also many species that persist following devastating declines due to disease. The broad mechanisms that enable host persistence following declines include evolution of resistance or tolerance, changes in immunity and behaviour, compensatory recruitment, pathogen attenuation, environmental refugia, density-dependent transmission and changes in community composition. Here we examine the case of chytridiomycosis, the most important wildlife disease of the past century. We review the full breadth of mechanisms allowing host persistence, and synthesise research on host, pathogen, environmental and community factors driving persistence following chytridiomycosis-related declines and overview the current evidence and the information required to support each mechanism. We found that for most species the mechanisms facilitating persistence have not been identified. We illustrate how the mechanisms that drive long-term host population dynamics determine the most effective conservation management strategies. Therefore, understanding mechanisms of host persistence is important because many species continue to be threatened by disease, some of which will require intervention. The conceptual framework we describe is broadly applicable to other novel disease systems.
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Affiliation(s)
- Laura A Brannelly
- Veterinary BioSciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Vic, 3030, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia.,Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Maria P Ribas
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia.,Wildlife Conservation Medicine Research Group, Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Matthijs Hollanders
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Thais Sasso
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Mariel Familiar López
- School of Environment and Sciences, Griffith University, Gold Coast, Qld., 4215, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Auston M Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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7
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Kumar R, Malagon DA, Carter ED, Miller DL, Bohanon ML, Cusaac JPW, Peterson AC, Gray MJ. Experimental methodologies can affect pathogenicity of Batrachochytrium salamandrivorans infections. PLoS One 2020; 15:e0235370. [PMID: 32915779 PMCID: PMC7485798 DOI: 10.1371/journal.pone.0235370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Controlled experiments are one approach to understanding the pathogenicity of etiologic agents to susceptible hosts. The recently discovered fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has resulted in a surge of experimental investigations because of its potential to impact global salamander biodiversity. However, variation in experimental methodologies could thwart knowledge advancement by introducing confounding factors that make comparisons difficult among studies. Thus, our objective was to evaluate if variation in experimental methods changed inferences made on the pathogenicity of Bsal. We tested whether passage duration of Bsal culture, exposure method of the host to Bsal (water bath vs. skin inoculation), Bsal culturing method (liquid vs. plated), host husbandry conditions (aquatic vs. terrestrial), and skin swabbing frequency influenced diseased-induced mortality in a susceptible host species, the eastern newt (Notophthalmus viridescens). We found that disease-induced mortality was faster for eastern newts when exposed to a low passage isolate, when newts were housed in terrestrial environments, and if exposure to zoospores occurred via water bath. We did not detect differences in disease-induced mortality between culturing methods or swabbing frequencies. Our results illustrate the need to standardize methods among Bsal experiments. We provide suggestions for future Bsal experiments in the context of hypothesis testing and discuss the ecological implications of our results.
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Affiliation(s)
- Rajeev Kumar
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Daniel A. Malagon
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Edward Davis Carter
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Debra L. Miller
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Markese L. Bohanon
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Joseph Patrick W. Cusaac
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Anna C. Peterson
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Matthew J. Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
- * E-mail:
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8
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Robinson KA, Pereira KE, Bletz MC, Carter ED, Gray MJ, Piovia-Scott J, Romansic JM, Woodhams DC, Fritz-Laylin L. Isolation and maintenance of Batrachochytrium salamandrivorans cultures. DISEASES OF AQUATIC ORGANISMS 2020; 140:1-11. [PMID: 32618283 DOI: 10.3354/dao03488] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Discovered in 2013, the chytrid fungus Batrachochytrium salamandrivorans (Bsal) is an emerging amphibian pathogen that causes ulcerative skin lesions and multifocal erosion. A closely related pathogen, B. dendrobatidis (Bd), has devastated amphibian populations worldwide, suggesting that Bsal poses a significant threat to global salamander biodiversity. To expedite research into this emerging threat, we seek to standardize protocols across the field so that results of laboratory studies are reproducible and comparable. We have collated data and experience from multiple labs to standardize culturing practices of Bsal. Here we outline common culture practices including a medium for standardized Bsal growth, standard culturing protocols, and a method for isolating Bsal from infected tissue.
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Affiliation(s)
- Kristyn A Robinson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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9
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Abstract
Discovering that chytrid fungi cause chytridiomycosis in amphibians represented a paradigm shift in our understanding of how emerging infectious diseases contribute to global patterns of biodiversity loss. In this Review we describe how the use of multidisciplinary biological approaches has been essential to pinpointing the origins of amphibian-parasitizing chytrid fungi, including Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, as well as to timing their emergence, tracking their cycles of expansion and identifying the core mechanisms that underpin their pathogenicity. We discuss the development of the experimental methods and bioinformatics toolkits that have provided a fuller understanding of batrachochytrid biology and informed policy and control measures.
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10
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DiRenzo GV, Zipkin EF, Grant EHC, Royle JA, Longo AV, Zamudio KR, Lips KR. Eco-evolutionary rescue promotes host-pathogen coexistence. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1948-1962. [PMID: 30368999 DOI: 10.1002/eap.1792] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/12/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Emerging infectious pathogens are responsible for some of the most severe host mass mortality events in wild populations. Yet, effective pathogen control strategies are notoriously difficult to identify, in part because quantifying and forecasting pathogen spread and disease dynamics is challenging. Following an outbreak, hosts must cope with the presence of the pathogen, leading to host-pathogen coexistence or extirpation. Despite decades of research, little is known about host-pathogen coexistence post-outbreak when low host abundances and cryptic species make these interactions difficult to study. Using a novel disease-structured N-mixture model, we evaluate empirical support for three host-pathogen coexistence hypotheses (source-sink, eco-evolutionary rescue, and spatial variation in pathogen transmission) in a Neotropical amphibian community decimated by Batrachochytrium dendrobatidis (Bd) in 2004. During 2010-2014, we surveyed amphibians in Parque Nacional G. D. Omar Torríjos Herrera, Coclé Province, El Copé, Panama. We found that the primary driver of host-pathogen coexistence was eco-evolutionary rescue, as evidenced by similar amphibian survival and recruitment rates between infected and uninfected hosts. Average apparent monthly survival rates of uninfected and infected hosts were both close to 96%, and the expected number of uninfected and infected hosts recruited (via immigration/reproduction) was less than one host per disease state per 20-m site. The secondary driver of host-pathogen coexistence was spatial variation in pathogen transmission as we found that transmission was highest in areas of low abundance but there was no support for the source-sink hypothesis. Our results indicate that changes in the host community (i.e., through genetic or species composition) can reduce the impacts of emerging infectious disease post-outbreak. Our disease-structured N-mixture model represents a valuable advancement for conservation managers trying to understand underlying host-pathogen interactions and provides new opportunities to study disease dynamics in remnant host populations decimated by virulent pathogens.
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Affiliation(s)
- Graziella V DiRenzo
- Department of Biology, University of Maryland, College Park, Maryland, 20744, USA
- Department of Integrative Biology and Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Elise F Zipkin
- Department of Integrative Biology and Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Evan H Campbell Grant
- U.S. Geological Survey, Patuxent Wildlife Research Center, SO Conte Anadromous Fish Research Lab, Turners Falls, Massachusetts, 01376, USA
| | - J Andrew Royle
- U.S. Geological Survey, Patuxent Wildlife Research Center, Laurel, Maryland, 20708-4017, USA
| | - Ana V Longo
- Department of Biology, University of Maryland, College Park, Maryland, 20744, USA
| | - Kelly R Zamudio
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, New York, 14583, USA
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, Maryland, 20744, USA
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11
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Effects of Emerging Infectious Diseases on Amphibians: A Review of Experimental Studies. DIVERSITY-BASEL 2018. [DOI: 10.3390/d10030081] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Numerous factors are contributing to the loss of biodiversity. These include complex effects of multiple abiotic and biotic stressors that may drive population losses. These losses are especially illustrated by amphibians, whose populations are declining worldwide. The causes of amphibian population declines are multifaceted and context-dependent. One major factor affecting amphibian populations is emerging infectious disease. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the fungi Batrachochytrium dendrobatidis and B. salamandrivorans, and ranaviruses. In this review, we assess the effects of these three pathogens on amphibian hosts as found through experimental studies. Such studies offer valuable insights to the causal factors underpinning broad patterns reported through observational studies. We summarize key findings from experimental studies in the laboratory, in mesocosms, and from the field. We also summarize experiments that explore the interactive effects of these pathogens with other contributors of amphibian population declines. Though well-designed experimental studies are critical for understanding the impacts of disease, inconsistencies in experimental methodologies limit our ability to form comparisons and conclusions. Studies of the three pathogens we focus on show that host susceptibility varies with such factors as species, host age, life history stage, population and biotic (e.g., presence of competitors, predators) and abiotic conditions (e.g., temperature, presence of contaminants), as well as the strain and dose of the pathogen, to which hosts are exposed. Our findings suggest the importance of implementing standard protocols and reporting for experimental studies of amphibian disease.
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12
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Miller CA, Tasse Taboue GC, Ekane MMP, Robak M, Sesink Clee PR, Richards-Zawacki C, Fokam EB, Fuashi NA, Anthony NM. Distribution modeling and lineage diversity of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in a central African amphibian hotspot. PLoS One 2018; 13:e0199288. [PMID: 29924870 PMCID: PMC6010240 DOI: 10.1371/journal.pone.0199288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
The amphibian disease chytridiomycosis in amphibians is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) and has resulted in dramatic declines and extinctions of amphibian populations worldwide. A hypervirulent, globally-dispersed pandemic lineage (Bd-GPL) is thought to be largely responsible for population declines and extinctions, although numerous endemic lineages have also been found. Recent reports of amphibian declines have been linked to the emergence of Bd in Cameroon, a major hotspot of African amphibian diversity. However, it is not known whether Bd-GPL or other lineages have been found in this region. This study therefore aims to examine Bd lineage diversity in the region and predict the distribution of this pathogen under current and future climate conditions using data from this study and from historical records. Almost 15% (52/360) of individuals tested positive for Bd using a standard quantitative PCR diagnostic. Infected amphibians were found at all eight sites sampled in this study. Species distribution models generated in BIOMOD2 indicate that areas with highest predicted environmental suitability occur in the Cameroon highlands and several protected areas throughout the country. These areas of high environmental suitability for Bd are projected to shift or decrease in size under future climate change. However, montane regions with high amphibian diversity are predicted to remain highly suitable. Phylogenetic analysis of the ITS sequences obtained from a set of positive Bd samples indicate that most fall within the Bd-GPL lineage while the remainder group with isolates from either Brazil or South Korea. Although more in depth phylogenetic analyses are needed, identification of Bd-GPL lineages in areas of high amphibian diversity emphasizes the need to continue to monitor for Bd and develop appropriate conservation strategies to prevent its further spread.
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Affiliation(s)
- Courtney A. Miller
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America
| | - Geraud Canis Tasse Taboue
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
- Institute of Geological and Mining Research, Yaoundé, Cameroon
| | - Mary M. P. Ekane
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
| | - Matthew Robak
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America
| | - Paul R. Sesink Clee
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Corinne Richards-Zawacki
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Eric B. Fokam
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
| | | | - Nicola M. Anthony
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America
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13
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Valenzuela-Sánchez A, O'Hanlon SJ, Alvarado-Rybak M, Uribe-Rivera DE, Cunningham AA, Fisher MC, Soto-Azat C. Genomic epidemiology of the emerging pathogen Batrachochytrium dendrobatidis from native and invasive amphibian species in Chile. Transbound Emerg Dis 2017; 65:309-314. [PMID: 29205924 DOI: 10.1111/tbed.12775] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Indexed: 11/29/2022]
Abstract
Emerging fungal diseases represent a threat to food security, animal and human health worldwide. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions. For the first time, Bd was cultured from native and non-native wild amphibians in Chile. Phylogenomic analyses revealed that Chilean isolates AVS2, AVS4 and AVS7 group within the global panzootic lineage of Bd (BdGPL) in a single highly supported clade that includes a genotype previously isolated from the United Kingdom. Our results extend the known distribution of BdGPL in South America and suggest a single and relatively recent introduction of BdGPL into the country, providing additional support to the role of anthropogenic activity in the global spread of this panzootic lineage.
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Affiliation(s)
- A Valenzuela-Sánchez
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Santiago, Chile.,ONG Ranita de Darwin, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, UK
| | - S J O'Hanlon
- Department of Infectious Disease Epidemiology, School of Public Health, St Mary's, Imperial College London, London, UK
| | - M Alvarado-Rybak
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, UK
| | | | - A A Cunningham
- Institute of Zoology, Zoological Society of London, London, UK
| | - M C Fisher
- Department of Infectious Disease Epidemiology, School of Public Health, St Mary's, Imperial College London, London, UK
| | - C Soto-Azat
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Santiago, Chile
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14
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Wilber MQ, Knapp RA, Toothman M, Briggs CJ. Resistance, tolerance and environmental transmission dynamics determine host extinction risk in a load-dependent amphibian disease. Ecol Lett 2017; 20:1169-1181. [PMID: 28745026 DOI: 10.1111/ele.12814] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 05/12/2017] [Accepted: 06/21/2017] [Indexed: 01/05/2023]
Abstract
While disease-induced extinction is generally considered rare, a number of recently emerging infectious diseases with load-dependent pathology have led to extinction in wildlife populations. Transmission is a critical factor affecting disease-induced extinction, but the relative importance of transmission compared to load-dependent host resistance and tolerance is currently unknown. Using a combination of models and experiments on an amphibian species suffering extirpations from the fungal pathogen Batrachochytrium dendrobatidis (Bd), we show that while transmission from an environmental Bd reservoir increased the ability of Bd to invade an amphibian population and the extinction risk of that population, Bd-induced extinction dynamics were far more sensitive to host resistance and tolerance than to Bd transmission. We demonstrate that this is a general result for load-dependent pathogens, where non-linear resistance and tolerance functions can interact such that small changes in these functions lead to drastic changes in extinction dynamics.
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Affiliation(s)
- Mark Q Wilber
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Roland A Knapp
- Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth Lakes, CA, 93546, USA
| | - Mary Toothman
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Cheryl J Briggs
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
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15
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Jaeger JR, Waddle AW, Rivera R, Harrison DT, Ellison S, Forrest MJ, Vredenburg VT, van Breukelen F. Batrachochytrium dendrobatidis and the Decline and Survival of the Relict Leopard Frog. ECOHEALTH 2017; 14:285-295. [PMID: 28439781 DOI: 10.1007/s10393-017-1240-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 06/07/2023]
Abstract
Epizootic disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is a major driver of amphibian declines, yet many amphibians declined before the pathogen was described. The Relict Leopard Frog, Rana onca (=Lithobates onca), was nearly extinct, with the exception of populations within a few geothermal springs. Growth of Bd, however, is limited by high water temperature, and geothermal springs may have provided refuge during outbreaks of chytridiomycosis. We conducted field surveys and laboratory experiments to assess the susceptibility of R. onca to Bd. In the field, we found Bd at one of the two areas where remnant populations of R. onca still occur, but not in the other. In the laboratory, we infected juvenile frogs from these two areas with two hypervirulent Bd isolates associated with declines in other ranid species. In our experiments, these Bd isolates did not affect survivorship of R. onca and most infections (64%) were cleared by the end of the experiments. We propose that R. onca either has inherent resistance to Bd or has recently evolved such resistance. These results may be important for conservation efforts aimed at establishing new populations of R. onca across a landscape where Bd exists. Resistance, however, varies among life stages, and we also did not assess Bd from the local environment. We caution that the resistance we observed for young frogs under laboratory conditions may not translate to the situation for R. onca in the wild.
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Affiliation(s)
- Jef R Jaeger
- School of Life Sciences, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 454004, Las Vegas, NV, 89154-4004, USA.
| | - Anthony W Waddle
- School of Life Sciences, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 454004, Las Vegas, NV, 89154-4004, USA
| | - Rebeca Rivera
- School of Life Sciences, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 454004, Las Vegas, NV, 89154-4004, USA
| | - D Tyler Harrison
- School of Life Sciences, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 454004, Las Vegas, NV, 89154-4004, USA
| | - Silas Ellison
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | | | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | - Frank van Breukelen
- School of Life Sciences, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 454004, Las Vegas, NV, 89154-4004, USA
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16
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Voyles J, Johnson LR, Rohr J, Kelly R, Barron C, Miller D, Minster J, Rosenblum EB. Diversity in growth patterns among strains of the lethal fungal pathogen Batrachochytrium dendrobatidis across extended thermal optima. Oecologia 2017; 184:363-373. [PMID: 28424893 PMCID: PMC5487841 DOI: 10.1007/s00442-017-3866-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 04/05/2017] [Indexed: 12/27/2022]
Abstract
The thermal sensitivities of organisms regulate a wide range of ecological interactions, including host–parasite dynamics. The effect of temperature on disease ecology can be remarkably complex in disease systems where the hosts are ectothermic and where thermal conditions constrain pathogen reproductive rates. Amphibian chytridiomycosis, caused by the pathogen Batrachochytrium dendrobatidis (Bd), is a lethal fungal disease that is influenced by temperature. However, recent temperature studies have produced contradictory findings, suggesting that our current understanding of thermal effects on Bd may be incomplete. We investigated how temperature affects three different Bd strains to evaluate diversity in thermal responses. We quantified growth across the entire thermal range of Bd, and beyond the known thermal limits (Tmax and Tmin). Our results show that all Bd strains remained viable and grew following 24 h freeze (−12 °C) and heat shock (28 °C) treatments. Additionally, we found that two Bd strains had higher logistic growth rates (r) and carrying capacities (K) at the upper and lower extremities of the temperature range, and especially in low temperature conditions (2–3 °C). In contrast, a third strain exhibited relatively lower growth rates and carrying capacities at these same thermal extremes. Overall, our results suggest that there is considerable variation among Bd strains in thermal tolerance, and they establish a new thermal sensitivity profile for Bd. More generally, our findings point toward important questions concerning the mechanisms that dictate fungal thermal tolerances and temperature-dependent pathogenesis in other fungal disease systems.
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Affiliation(s)
- Jamie Voyles
- Department of Biology, University of Nevada-Reno, Reno, NV, 87801, USA.
| | - Leah R Johnson
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
- Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Jason Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Rochelle Kelly
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Carley Barron
- Department of Biology, New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801, USA
| | - Delaney Miller
- Department of Biology, New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801, USA
| | - Josh Minster
- Department of Biology, New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801, USA
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy and Management, University of California- Berkeley, Berkeley, CA, 94720-3144, USA
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17
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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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18
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Insights From Genomics Into Spatial and Temporal Variation in Batrachochytrium dendrobatidis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016. [PMID: 27571698 DOI: 10.1016/bs.pmbts.2016.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Advances in genetics and genomics have provided new tools for the study of emerging infectious diseases. Researchers can now move quickly from simple hypotheses to complex explanations for pathogen origin, spread, and mechanisms of virulence. Here we focus on the application of genomics to understanding the biology of the fungal pathogen Batrachochytrium dendrobatidis (Bd), a novel and deadly pathogen of amphibians. We provide a brief history of the system, then focus on key insights into Bd variation garnered from genomics approaches, and finally, highlight new frontiers for future discoveries. Genomic tools have revealed unexpected complexity and variation in the Bd system suggesting that the history and biology of emerging pathogens may not be as simple as they initially seem.
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20
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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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21
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22
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James TY, Toledo LF, Rödder D, da Silva Leite D, Belasen AM, Betancourt-Román CM, Jenkinson TS, Soto-Azat C, Lambertini C, Longo AV, Ruggeri J, Collins JP, Burrowes PA, Lips KR, Zamudio KR, Longcore JE. Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research. Ecol Evol 2015; 5:4079-97. [PMID: 26445660 PMCID: PMC4588650 DOI: 10.1002/ece3.1672] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/25/2015] [Indexed: 12/18/2022] Open
Abstract
The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.
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Affiliation(s)
- Timothy Y James
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | - L Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-863 Brazil
| | - Dennis Rödder
- Section of Herpetology Zoologisches Forschungsmuseum Alexander Koenig Adenauerallee 160 53113 Bonn Germany
| | - Domingos da Silva Leite
- Laboratório de Antígenos Bacterianos II Departamento de Genética, Evolução e Bioagentes Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-862 Brazil
| | - Anat M Belasen
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | | | - Thomas S Jenkinson
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad Facultad de Ecología y Recursos Naturales, Universidad Andres Bello Santiago Chile
| | - Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-863 Brazil
| | - Ana V Longo
- Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853
| | - Joice Ruggeri
- Departamento de Zoologia Laboratório de Anfíbios e Répteis Universidade Federal do Rio de Janeiro, Instituto de Biologia Ilha do Fundão, Caixa postal: 68044 Rio de Janeiro RJ CEP 21941-590 Brazil
| | - James P Collins
- School of Life Sciences Arizona State University PO Box 874501 Tempe Arizona 85287-4501
| | | | - Karen R Lips
- Department of Biology University of Maryland College Park Maryland 20901
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853
| | - Joyce E Longcore
- School of Biology and Ecology University of Maine Orono Maine 04469-5722
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