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Martin H. C, Ibáñez R, Nothias LF, Caraballo-Rodríguez AM, Dorrestein PC, Gutiérrez M. Metabolites from Microbes Isolated from the Skin of the Panamanian Rocket Frog Colostethus panamansis (Anura: Dendrobatidae). Metabolites 2020; 10:E406. [PMID: 33065987 PMCID: PMC7601193 DOI: 10.3390/metabo10100406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/28/2020] [Accepted: 10/09/2020] [Indexed: 01/02/2023] Open
Abstract
The Panamanian rocket frog Colostethus panamansis (family Dendrobatidae) has been affected by chytridiomycosis, a deadly disease caused by the fungus Batrachochytrium dendrobatidis (Bd). While there are still uninfected frogs, we set out to isolate microbes from anatomically distinct regions in an effort to create a cultivable resource within Panama for potential drug/agricultural/ecological applications that perhaps could also be used as part of a strategy to protect frogs from infections. To understand if there are specific anatomies that should be explored in future applications of this resource, we mapped skin-associated bacteria of C. panamansis and their metabolite production potential by mass spectrometry on a 3D model. Our results indicate that five bacterial families (Enterobacteriaceae, Comamonadaceae, Aeromonadaceae, Staphylococcaceae and Pseudomonadaceae) dominate the cultivable microbes from the skin of C. panamansis. The combination of microbial classification and molecular analysis in relation to the anti-Bd inhibitory databases reveals the resource has future potential for amphibian conservation.
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Affiliation(s)
- Christian Martin H.
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Clayton, Panama 0843-01103, Panama;
- Department of Biotechnology, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522510, India
| | - Roberto Ibáñez
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama 0843-03092, Panama;
| | - Louis-Félix Nothias
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA; (L.-F.N.); (A.M.C.-R.); (P.C.D.)
| | - Andrés Mauricio Caraballo-Rodríguez
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA; (L.-F.N.); (A.M.C.-R.); (P.C.D.)
| | - Pieter C. Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA; (L.-F.N.); (A.M.C.-R.); (P.C.D.)
| | - Marcelino Gutiérrez
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Clayton, Panama 0843-01103, Panama;
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52
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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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53
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Rollins-Smith LA. Global Amphibian Declines, Disease, and the Ongoing Battle between Batrachochytrium Fungi and the Immune System. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.178] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Louise A. Rollins-Smith
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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54
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Zamudio KR, McDonald CA, Belasen AM. High Variability in Infection Mechanisms and Host Responses: A Review of Functional Genomic Studies of Amphibian Chytridiomycosis. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.189] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kelly R. Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-2701, USA
| | - Cait A. McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-2701, USA
| | - Anat M. Belasen
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-2701, USA
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55
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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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56
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Malagon DA, Melara LA, Prosper OF, Lenhart S, Carter ED, Fordyce JA, Peterson AC, Miller DL, Gray MJ. Host density and habitat structure influence host contact rates and Batrachochytrium salamandrivorans transmission. Sci Rep 2020; 10:5584. [PMID: 32221329 PMCID: PMC7101388 DOI: 10.1038/s41598-020-62351-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 03/11/2020] [Indexed: 12/22/2022] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is an emerging invasive pathogen that is highly pathogenic to salamander species. Modeling infection dynamics in this system can facilitate proactive efforts to mitigate this pathogen's impact on North American species. Given its widespread distribution and high abundance, the eastern newt (Notophthalmus viridescens) has the potential to significantly influence Bsal epidemiology. We designed experiments to 1) estimate contact rates given different host densities and habitat structure and 2) estimate the probability of transmission from infected to susceptible individuals. Using parameter estimates from data generated during these experiments, we modeled infection and disease outcomes for a population of newts using a system of differential equations. We found that host contact rates were density-dependent, and that adding habitat structure reduced contacts. The probability of Bsal transmission given contact between newts was very high (>90%) even at early stages of infection. Our simulations show rapid transmission of Bsal among individuals following pathogen introduction, with infection prevalence exceeding 90% within one month and >80% mortality of newts in three months. Estimates of basic reproductive rate (R0) of Bsal for eastern newts were 1.9 and 3.2 for complex and simple habitats, respectively. Although reducing host density and increasing habitat complexity might decrease transmission, these management strategies may be ineffective at stopping Bsal invasion in eastern newt populations due to this species’ hyper-susceptibility.
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Affiliation(s)
- Daniel A Malagon
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Luis A Melara
- Department of Mathematics, Shippensburg University, Shippensburg, PA, 17257, USA
| | - Olivia F Prosper
- Department of Mathematics, University of Kentucky, Lexington, KY, 40506, USA.,Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN, 37996, USA
| | - Edward Davis Carter
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - J A Fordyce
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Anna C Peterson
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Debra L Miller
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.,Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, 37996, USA
| | - Matthew J Gray
- Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA.
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57
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Barnhart KL, Bletz MC, LaBumbard BC, Tokash-Peters AG, Gabor CR, Woodhams DC. Batrachochytrium salamandrivorans ELICITS ACUTE STRESS RESPONSE IN SPOTTED SALAMANDERS BUT NOT INFECTION OR MORTALITY. Anim Conserv 2020; 23:533-546. [PMID: 33071596 DOI: 10.1111/acv.12565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emerging fungal pathogen Batrachochytrium salamandrivorans (Bsal) is a major threat to amphibian species worldwide with potential to infect many species if it invades salamander biodiversity hotspots in the Americas. Bsal can cause the disease chytridiomycosis, and it is important to assess the risk of Bsal-induced chytridiomycosis to species in North America. We evaluated the susceptibility to Bsal of the common and widespread spotted salamander, Ambystoma maculatum, across life history stages and monitored the effect of Bsal exposure on growth rate and response of the stress hormone, corticosterone. We conclude that spotted salamanders appear resistant to Bsal because they showed no indication of disease or infection, and experienced minor effects on growth upon exposure. While we focused on a single population for this study, results were consistent across conditions of exposure including high or repeated doses of Bsal, life-stage at exposure, environmental conditions including two temperatures and two substrates, and promoting pathogen infectivity by conditioning Bsal cultures with thyroid hormone. Exposure to high levels of Bsal elicited an acute but not chronic increase in corticosterone in spotted salamanders, and reduced growth. We hypothesize that the early acute increase in corticosterone facilitated mounting an immune response to the pathogen, perhaps through immunoredistribution to the skin, but further study is needed to determine immune responses to Bsal. These results will contribute to development of appropriate Bsal management plans to conserve species at risk of emerging disease.
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Affiliation(s)
- Kelly L Barnhart
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Molly C Bletz
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Brandon C LaBumbard
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Amanda G Tokash-Peters
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Caitlin R Gabor
- Texas State University, Department of Biology, 601 University Drive, San Marcos, TX 78666
| | - Douglas C Woodhams
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
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58
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Reference gene screening of Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans for quantitative real-time PCR studies. Sci Rep 2019; 9:18534. [PMID: 31811175 PMCID: PMC6898426 DOI: 10.1038/s41598-019-54582-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 11/15/2019] [Indexed: 11/09/2022] Open
Abstract
Real-time quantitative PCR studies largely depend on reference genes for the normalization of gene expression. Stable reference genes should be accurately selected in order to obtain reliable results. We here present a study screening commonly used reference genes (TEF1F, α-centractin, Ctsyn1, GAPDH, R6046, APRT and TUB) in the chytrid fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal), which cause the lethal amphibian skin disease chytridiomycosis. We evaluated the stability of the reference gene candidates during different growth stages of the fungi, using different statistical software packages: ΔCT, BestKeeper, GeNorm, NormFinder and RefFinder. In order to reflect the in vivo situation, the stability of the candidates was assessed when taking all growth stages into account. Using an ex-vivo approach, we tested whether the expression of GAPDH, TUB, R6046 and APRT (Bd) and GAPDH, TUB, R6046 and α-centractin (Bsal) remained stable when these fungi came in contact with host tissue. Finally, their role as in vivo reference genes was examined in skin tissue of experimentally infected midwife toads (Alytes obstetricans) (Bd) and fire salamanders (Salamandra salamandra) (Bsal). Summarized, the present study provides guidance for selecting appropriate reference genes when analyzing expression patterns of these fungal organisms during different growth stages and in Bd- or Bsal-infected tissues.
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59
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Waddle AW, Levy JE, Rivera R, van Breukelen F, Nash M, Jaeger JR. Population-Level Resistance to Chytridiomycosis is Life-Stage Dependent in an Imperiled Anuran. ECOHEALTH 2019; 16:701-711. [PMID: 31654279 DOI: 10.1007/s10393-019-01446-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Amphibian declines caused by chytridiomycosis have been severe, but some susceptible populations have persisted or even recovered. Resistance to the causal agent Batrachochytrium dendrobatidis (Bd) could result from alleles of the adaptive immune system. During metamorphosis, however, immune systems may not be fully functional, implying that an effective immune response to Bd may be life-stage dependent. We evaluated the susceptibility of the relict leopard frog (Rana onca) sourced from two areas where Bd was present or absent, and where the populations appeared to show differences in pathogen resistance. We evaluated whether population-level resistance manifested across life stages using challenge experiments with late-stage tadpoles (Gosner stage 31-38), metamorphs (stage 45-46), and juvenile frogs. We used three different Bd isolates including one from wild R. onca to challenge juvenile frogs and focused on the isolate from R. onca to challenge tadpoles and resulting metamorphs. We found that juveniles from the Bd exposed population were 5.5 times more likely to survive Bd infection and 10 times more likely to clear infections than those from the area without Bd. In contrast, and regardless of the source area, we observed 98% survivorship of tadpoles, but only 19% survivorship of resulting metamorphs following re-exposure. Given the low survivorship of exposed metamorphs in the laboratory, we speculate on how resistance characteristics, whether adaptive or innate, that do not manifest at each life stage could develop in the wild. We suggest that seasonal high temperatures during times when metamorphosis appears common may modulate the effects of the pathogen during this most susceptible life stage.
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Affiliation(s)
- Anthony W Waddle
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154, USA.
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 250 Princes Hwy, Werribee, VIC, 3030, Australia.
| | - Joshua E Levy
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154, USA
| | - Rebeca Rivera
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154, USA
| | - Frank van Breukelen
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154, USA
| | - Maliha Nash
- , 2111 SE Marine Science Dr., Newport, OR, 97365, USA
| | - Jef R Jaeger
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154, USA
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60
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Verbrugghe E, Van Rooij P, Favoreel H, Martel A, Pasmans F. In vitro modeling of Batrachochytrium dendrobatidis infection of the amphibian skin. PLoS One 2019; 14:e0225224. [PMID: 31725762 PMCID: PMC6855447 DOI: 10.1371/journal.pone.0225224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/30/2019] [Indexed: 11/19/2022] Open
Abstract
The largest current disease-induced loss of vertebrate biodiversity is due to chytridiomycosis and despite the increasing understanding of the pathogenesis, knowledge unravelling the early host-pathogen interactions remains limited. Batrachochytrium dendrobatidis (Bd) zoospores attach to and invade the amphibian epidermis, with subsequent invasive growth in the host skin. Availability of an in vitro assay would facilitate in depth study of this interaction while reducing the number of experimental animals needed. We describe a fluorescent cell-based in vitro infection model that reproduces host-Bd interactions. Using primary keratinocytes from Litoria caerulea and the epithelial cell line A6 from Xenopus laevis, we reproduced different stages of host cell infection and intracellular growth of Bd, resulting in host cell death, a key event in chytridiomycosis. The presented in vitro models may facilitate future mechanistic studies of host susceptibility and pathogen virulence.
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Affiliation(s)
- Elin Verbrugghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- * E-mail:
| | - Pascale Van Rooij
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Herman Favoreel
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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61
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Carter ED, Miller DL, Peterson AC, Sutton WB, Cusaac JPW, Spatz JA, Rollins‐Smith L, Reinert L, Bohanon M, Williams LA, Upchurch A, Gray MJ. Conservation risk of
Batrachochytrium salamandrivorans
to endemic lungless salamanders. Conserv Lett 2019. [DOI: 10.1111/conl.12675] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Edward Davis Carter
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Debra L. Miller
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
- Department of Biomedical and Diagnostic Sciences, College of Veterinary MedicineUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Anna C. Peterson
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - William B. Sutton
- Department of Agricultural and Environmental SciencesTennessee State University Nashville Tennessee
| | - Joseph Patrick W. Cusaac
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Jennifer A. Spatz
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Louise Rollins‐Smith
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Laura Reinert
- Department of PathologyMicrobiology & ImmunologyVanderbilt University Nashville Tennessee
| | - Markese Bohanon
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
| | - Lori A. Williams
- North Carolina Wildlife Resources Commission Raleigh North Carolina
| | | | - Matthew J. Gray
- Center for Wildlife Health, Department of ForestryWildlife and FisheriesUniversity of Tennessee Institute of Agriculture Knoxville Tennessee
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62
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Ossiboff RJ, Towe AE, Brown MA, Longo AV, Lips KR, Miller DL, Carter ED, Gray MJ, Frasca S. Differentiating Batrachochytrium dendrobatidis and B. salamandrivorans in Amphibian Chytridiomycosis Using RNAScope ® in situ Hybridization. Front Vet Sci 2019; 6:304. [PMID: 31572738 PMCID: PMC6751264 DOI: 10.3389/fvets.2019.00304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/28/2019] [Indexed: 12/25/2022] Open
Abstract
Batrachochytrium dendrobatidis and B. salamandrivorans are important amphibian pathogens responsible for morbidity and mortality in free-ranging and captive frogs, salamanders, and caecilians. While B. dendrobatidis has a widespread global distribution, B. salamandrivorans has only been detected in amphibians in Asia and Europe. Although molecular detection methods for these fungi are well-characterized, differentiation of the morphologically similar organisms in the tissues of affected amphibians is incredibly difficult. Moreover, an accurate tool to identify and differentiate Batrachochytrium in affected amphibian tissues is essential for a specific diagnosis of the causative agent in chytridiomycosis cases. To address this need, an automated dual-plex chromogenic RNAScope®in situ hybridization (ISH) assay was developed and characterized for simultaneous detection and differentiation of B. dendrobatidis and B. salamandrivorans. The assay, utilizing double Z target probe pairs designed to hybridize to 28S rRNA sequences, was specific for the identification of both organisms in culture and in formalin-fixed paraffin-embedded amphibian tissues. The assay successfully identified organisms in tissue samples from five salamander and one frog species preserved in formalin for up to 364 days and was sensitive for the detection of Batrachochytrium in animals with qPCR loads as low as 1.1 × 102 zoospores/microliter. ISH staining of B. salamandrivorans also highlighted the infection of dermal cutaneous glands, a feature not observed in amphibian B. dendrobatidis cases and which may play an important role in B. salamandrivorans pathogenesis in salamanders. The developed ISH assay will benefit both amphibian chytridiomycosis surveillance projects and pathogenesis studies by providing a reliable tool for Batrachochytrium differentiation in tissues.
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Affiliation(s)
- Robert J Ossiboff
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Anastasia E Towe
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Melissa A Brown
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Ana V Longo
- Department of Biology, University of Florida, Gainesville, FL, United States.,Department of Biology, University of Maryland College Park, College Park, MD, United States
| | - Karen R Lips
- Department of Biology, University of Maryland College Park, College Park, MD, United States
| | - Debra L Miller
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Knoxville, TN, United States.,Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - E Davis Carter
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Salvatore Frasca
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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63
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Cummins D, Kennington WJ, Rudin-Bitterli T, Mitchell NJ. A genome-wide search for local adaptation in a terrestrial-breeding frog reveals vulnerability to climate change. GLOBAL CHANGE BIOLOGY 2019; 25:3151-3162. [PMID: 31273907 DOI: 10.1111/gcb.14703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
Terrestrial-breeding amphibians are likely to be vulnerable to warming and drying climates, as their embryos require consistent moisture for successful development. Adaptation to environmental change will depend on sufficient genetic variation existing within or between connected populations. Here, we use Single Nucleotide Polymorphism (SNP) data to investigate genome-wide patterns in genetic diversity, gene flow and local adaptation in a terrestrial-breeding frog (Pseudophryne guentheri) subject to a rapidly drying climate and recent habitat fragmentation. The species was sampled across 12 central and range-edge populations (192 samples), and strong genetic structure was apparent, as were high inbreeding coefficients. Populations showed differences in genetic diversity, and one population lost significant genetic diversity in a decade. More than 500 SNP loci were putatively under directional selection, and 413 of these loci were correlated with environmental variables such as temperature, rainfall, evaporation and soil moisture. One locus showed homology to a gene involved in the activation of maturation in Xenopus oocytes, which may facilitate rapid development of embryos in drier climates. The low genetic diversity, strong population structuring and presence of local adaptation revealed in this study shows why management strategies such as targeted gene flow may be necessary to assist isolated populations to adapt to future climates.
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Affiliation(s)
- Deanne Cummins
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - W Jason Kennington
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Tabitha Rudin-Bitterli
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Nicola J Mitchell
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
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64
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Ashford MA, Palackdharry SM, Sadd BM, Bowden RM, Vogel LA. Intestinal B cells in the red-eared slider turtle, Trachemys scripta: Anatomical distribution and implications for ecological interactions with pathogenic microbes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:407-415. [PMID: 31328906 DOI: 10.1002/jez.2307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/05/2019] [Accepted: 06/13/2019] [Indexed: 12/17/2022]
Abstract
Disease is a significant threat in the global decline of reptile species. Many aquatic reptiles live in habitats with high levels of opportunistic microbial pathogens, yet little is known about their immune system. Gut-associated lymphoid tissue is vital for protection against ingested pathogens and maintenance of normal gut microbiota. In mammals, gut mucosal immunity is well-characterized and mucosal surfaces are coated in protective antibodies. However, reptiles lack lymph nodes and Peyer's patches, which are the major sites of mammalian B cell responses. The presence or distribution of mucosal B cells in reptiles is unknown. In this study, we first set out to determine if B cells could be detected in intestinal tissues of red-eared slider turtles, Trachemys scripta. Using whole-mount immunochemistry and a primary antibody to turtle antibody light chains, we identified widely distributed B cell aggregates within the small intestine of hatchling turtles. These aggregates appeared similar to isolated lymphoid follicles (ILFs) in mammals and the frequency was much higher in distal intestinal sections than in proximal sections. To determine if these structures were inducible in the presence of microbes, we introduced an enteric Salmonella species through oral gavage. Analysis of intestinal tissues revealed that hatchlings exposed to Salmonella exhibited significantly more of these aggregates when compared with those that did not receive bacteria. These studies provide the first evidence for B cell-containing ILF-like structures in reptiles and provide novel information about gut immunity in nonmammalian vertebrates that could have important implications for ecological interactions with pathogens.
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Affiliation(s)
- Marc A Ashford
- School of Biological Sciences, Illinois State University, Normal, IIlinois
| | | | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Normal, IIlinois
| | - Rachel M Bowden
- School of Biological Sciences, Illinois State University, Normal, IIlinois
| | - Laura A Vogel
- School of Biological Sciences, Illinois State University, Normal, IIlinois
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65
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Hettyey A, Ujszegi J, Herczeg D, Holly D, Vörös J, Schmidt BR, Bosch J. Mitigating Disease Impacts in Amphibian Populations: Capitalizing on the Thermal Optimum Mismatch Between a Pathogen and Its Host. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00254] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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66
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The invasive red swamp crayfish (Procambarus clarkii) increases infection of the amphibian chytrid fungus (Batrachochytrium dendrobatidis). Biol Invasions 2019. [DOI: 10.1007/s10530-019-02041-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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67
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Doody KA, Ohmer ME, Cramp RL, Franklin CE. Do Frogs Infected with Batrachochytrium dendrobatidis Avoid Water While Sloughing? HERPETOLOGICA 2019. [DOI: 10.1655/d-18-00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kathleen A. Doody
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Michel E.B. Ohmer
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Rebecca L. Cramp
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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68
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Chandler HC, Allender MC, Stegenga BS, Haynes E, Ospina E, Stevenson DJ. Ophidiomycosis prevalence in Georgia's Eastern Indigo Snake (Drymarchon couperi) populations. PLoS One 2019; 14:e0218351. [PMID: 31188875 PMCID: PMC6561582 DOI: 10.1371/journal.pone.0218351] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/30/2019] [Indexed: 11/19/2022] Open
Abstract
Wildlife diseases have posed a significant challenge to the conservation of many species in recent years. Diseases have been implicated in population declines over large geographic areas, with severe disease outbreaks leading to either local or complete extinctions of wild populations. Ophidiomycosis, commonly known as snake fungal disease, is caused by the fungus Ophidiomyces ophiodiicola, which has been documented in snake populations across the eastern and southern United States. We collected swab samples from the federally threatened Eastern Indigo Snake (Drymarchon couperi) in populations across the species' Georgia range. We used quantitative PCR to determine the presence of O. ophiodiicola DNA and also recorded skin abnormalities characteristic of ophidiomycosis. From 1 September 2016 to 4 August 2018, Eastern Indigo Snakes tested positive for O. ophiodiicola DNA on 47 of 107 occasions (43.9%) and tested negative for fungal DNA but had skin lesions consistent with ophidiomycosis on 42 occasions (39.3%). Symptomatic and qPCR positive individuals were more likely to be encountered during January and February when compared to November and December. We found no effect of sex (p = 0.517), age-class (p = 0.106), or body size (snout-vent length: p = 0.083; mass: p = 0.206; body condition: p = 0.063) on ophidiomycosis status. Over the two-year study, we encountered individuals in which infection was clearly negatively impacting overall health and also documented individuals in which infection apparently cleared from one year to the next. These results demonstrate that O. ophiodiicola and lesions characteristic of ophidiomycosis are widespread in Georgia's Eastern Indigo Snake populations. However, there are many unanswered questions regarding this disease, including the effects of disease on populations and individuals, the presence of infection vectors, and the change in prevalence over time. More research is needed to address ophidiomycosis and understand its impacts on ongoing conservation efforts.
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Affiliation(s)
| | - Matthew C. Allender
- Wildlife Epidemiology Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign, Champaign, Illinois, United States of America
| | | | - Ellen Haynes
- Wildlife Epidemiology Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Emilie Ospina
- Wildlife Epidemiology Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
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69
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Fu M, Waldman B. Ancestral chytrid pathogen remains hypervirulent following its long coevolution with amphibian hosts. Proc Biol Sci 2019; 286:20190833. [PMID: 31161901 DOI: 10.1098/rspb.2019.0833] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Many amphibian species around the world, except in Asia, suffer morbidity and mortality when infected by the emerging infectious pathogen Batrachochytrium dendrobatidis (Bd). A lineage of the amphibian chytrid fungus isolated from South Korean amphibians (BdAsia-1) is evolutionarily basal to recombinant global pandemic lineages (BdGPL) associated with worldwide amphibian population declines. In Asia, the Bd pathogen and its amphibian hosts have coevolved over 100 years or more. Thus, resilience of Asian amphibian populations to infection might result from attenuated virulence of endemic Bd lineages, evolved immunity to the pathogen or both. We compared susceptibilities of an Australasian amphibian, Litoria caerulea, known to lack resistance to BdGPL, with those of three Korean species, Bufo gargarizans, Bombina orientalis and Hyla japonica, after inoculation with BdAsia-1, BdGPL or a blank solution. Subjects became infected in all experimental treatments but Korean species rapidly cleared themselves of infection, regardless of Bd lineage. They survived with no apparent secondary effects. By contrast, L. caerulea, after infection by either BdAsia-1 or BdGPL, suffered deteriorating body condition and carried progressively higher Bd loads over time. Subsequently, most subjects died. Comparing their effects on L. caerulea, BdAsia-1 induced more rapid disease progression than BdGPL. The results suggest that genomic recombination with other lineages was not necessary for the ancestral Bd lineage to evolve hypervirulence over its long period of coevolution with amphibian hosts. The pathogen's virulence may have driven strong selection for immune responses in endemic Asian amphibian host species.
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Affiliation(s)
- Minjie Fu
- 1 Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University , Seoul 08826 , South Korea
| | - Bruce Waldman
- 1 Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University , Seoul 08826 , South Korea.,2 Department of Integrative Biology, Oklahoma State University , Stillwater, OK 74078 , USA
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70
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Lindauer A, May T, Rios-Sotelo G, Sheets C, Voyles J. Quantifying Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans Viability. ECOHEALTH 2019; 16:346-350. [PMID: 31124019 PMCID: PMC6682578 DOI: 10.1007/s10393-019-01414-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 01/20/2019] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
The disease chytridiomycosis is responsible for global amphibian declines. Chytridiomycosis is caused by Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), fungal pathogens with stationary and transmissible life stages. Establishing methods that quantify growth and survival of both life stages can facilitate research on the pathophysiology and disease ecology of these pathogens. We tested the efficacy of the MTT assay, a colorimetric test of cell viability, and found it to be a reliable method for quantifying the viability of Bd and Bsal stationary life stages. This method can provide insights into these pathogens' growth and reproduction to improve our understanding of chytridiomycosis.
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Affiliation(s)
- Alexa Lindauer
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Tiffany May
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Gabriela Rios-Sotelo
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Ciara Sheets
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Jamie Voyles
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV, 89557, USA.
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71
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Del Valle JM, Eisthen HL. Treatment of Chytridiomycosis in Laboratory Axolotls ( Ambystoma mexicanum) and Rough-skinned Newts ( Taricha granulosa). Comp Med 2019; 69:204-211. [PMID: 31142399 DOI: 10.30802/aalas-cm-18-000090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Chytridiomycosis is an infectious disease of amphibians caused by the fungal species Batrachochytrium dendrobatidis and B. salamandrivorans and has been implicated in the population decline of amphibian species worldwide. This case report describes a successful treatment protocol for chytridiomycosis in laboratory-maintained colonies of axolotls (Ambystoma mexicanum) and rough-skinned newts (Taricha granulosa). Over 12 mo, axolotls (n = 12) in a laboratory-reared colony developed multifocal erythematous dermatitis, mainly on the distal limbs and tails. Wild-caught newts handled by the same lab personnel were housed in an adjacent room and occasionally presented with abdominal distension and lethargy. Differentials included poor water quality, pathogen infection, parasitic infestation, and trauma. Antibiotic treatment of animals according to results of bacterial culture and sensitivity, combined with bleach disinfection of aquaria, did not resolve clinical signs. Skin swabs from clinically affected axolotls submitted for a newly available commercial screen were positive for B. dendrobatidis. Additional PCR and sequencing analysis revealed chytrid-positive animals among group-housed newts in 2 clinically unaffected aquaria and suspected PCR-positives for 2 affected newt aquaria and an additional axolotl. Axolotls with skin lesions (n = 2) and newts with abdominal distension and lethargy (n = 2) underwent experimental treatment with itraconazole submersion (0.002% to 0.0025%; 5 min daily for 10 d). This pilot treatment was well tolerated and led to clinical resolution. Subsequent itraconazole treatment of the entire colony led to regrowth of extremities and restoration of normal coloration among axolotls. During treatment, the facility was decontaminated, and additional biosecurity measures were developed. PCR results after the pilot treatment and subsequent full-colony treatments (at 1 wk, 1 mo, and 6 mo after treatment) were negative for the presence of B. dendrobatidis. Because chytridiomycosis is a reportable animal disease in our state, colonies officially remained quarantined until negative PCR results were obtained at least 6 mo after treatment.
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Affiliation(s)
| | - Heather L Eisthen
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan,
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72
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Walker DM, Leys JE, Grisnik M, Grajal-Puche A, Murray CM, Allender MC. Variability in snake skin microbial assemblages across spatial scales and disease states. ISME JOURNAL 2019; 13:2209-2222. [PMID: 31065028 PMCID: PMC6776063 DOI: 10.1038/s41396-019-0416-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 04/10/2019] [Accepted: 04/12/2019] [Indexed: 02/07/2023]
Abstract
Understanding how biological patterns translate into functional processes across different scales is a central question in ecology. Within a spatial context, extent is used to describe the overall geographic area of a study, whereas grain describes the overall unit of observation. This study aimed to characterize the snake skin microbiota (grain) and to determine host–microbial assemblage–pathogen effects across spatial extents within the Southern United States. The causative agent of snake fungal disease, Ophidiomyces ophiodiicola, is a fungal pathogen threatening snake populations. We hypothesized that the skin microbial assemblage of snakes differs from its surrounding environment, by host species, spatial scale, season, and in the presence of O. ophiodiicola. We collected snake skin swabs, soil samples, and water samples across six states in the Southern United States (macroscale extent), four Tennessee ecoregions (mesoscale extent), and at multiple sites within each Tennessee ecoregion (microscale extent). These samples were subjected to DNA extraction and quantitative PCR to determine the presence/absence of O. ophiodiicola. High-throughput sequencing was also utilized to characterize the microbial communities. We concluded that the snake skin microbial assemblage was partially distinct from environmental microbial communities. Snake host species was strongly predictive of the skin microbiota at macro-, meso-, and microscale spatial extents; however, the effect was variable across geographic space and season. Lastly, the presence of the fungal pathogen O. ophiodiicola is predictive of skin microbial assemblages across macro- and meso-spatial extents, and particular bacterial taxa associate with O. ophiodiicola pathogen load. Our results highlight the importance of scale regarding wildlife host–pathogen–microbial assemblage interactions.
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Affiliation(s)
- Donald M Walker
- Toxicology and Disease Group, Biology Department, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, USA.
| | - Jacob E Leys
- Department of Biology, Tennessee Technological University, Cookeville, TN, USA
| | - Matthew Grisnik
- Toxicology and Disease Group, Biology Department, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, USA
| | - Alejandro Grajal-Puche
- Toxicology and Disease Group, Biology Department, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, USA
| | | | - Matthew C Allender
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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73
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Briand A, Laidebeure S, Lécu A, Lemberger K, Nicolier A, Wohltmann A, Guillot J. Intradermal Infection by Chigger Mites (Endotrombicula Madagascariensis) in a Group of Mantella Baroni Frogs Illegally Imported From Madagascar. J Exot Pet Med 2019. [DOI: 10.1053/j.jepm.2018.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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74
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Verbrugghe E, Adriaensen C, Martel A, Vanhaecke L, Pasmans F. Growth Regulation in Amphibian Pathogenic Chytrid Fungi by the Quorum Sensing Metabolite Tryptophol. Front Microbiol 2019; 9:3277. [PMID: 30671052 PMCID: PMC6331427 DOI: 10.3389/fmicb.2018.03277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/17/2018] [Indexed: 01/06/2023] Open
Abstract
Amphibians face many threats leading to declines and extinctions, but the chytrid fungal skin pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) have been identified as the causative factors leading to one of the greatest disease-driven losses of amphibian biodiversity worldwide. Infection may lead to different clinical outcomes, and lethal infections are commonly associated with unrestricted, exponential fungal growth in the amphibian epidermis. Mechanisms underpinning Bd and Bsal growth in the amphibian host are poorly understood. Here, we describe a quorum sensing mechanism that allows cell-to-cell communication by Bd and Bsal in order to regulate fungal densities and infection strategies. Addition of chytrid culture supernatant to chytrid cultures resulted in a concentration-dependent growth reduction and using dialysis, small metabolites were shown to be the causative factor. U-HPLC-MS/MS and in vitro growth tests identified the aromatic alcohol tryptophol as a key metabolite in regulating fungal growth. We determined tryptophol kinetics in both Bd and Bsal and confirmed the autostimulatory mode of action of this quorum sensing metabolite. Finally, we linked expression of genes that might be involved in tryptophol production, with in vitro and in vivo chytrid growth. Our results show that Bd and Bsal fungi use tryptophol to act as multicellular entities in order to regulate their growth.
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Affiliation(s)
- Elin Verbrugghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Connie Adriaensen
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Lynn Vanhaecke
- Laboratory of Chemical Analysis, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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75
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Borteiro C, Kolenc F, Verdes JM, Martínez Debat C, Ubilla M. Sensitivity of histology for the detection of the amphibian chytrid fungus Batrachochytrium dendrobatidis. J Vet Diagn Invest 2019; 31:246-249. [PMID: 30661466 DOI: 10.1177/1040638718816116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Histology is often underappreciated for the detection of the amphibian pathogenic fungus Batrachochytrium dendrobatidis, the cause of the potentially lethal skin disease chytridiomycosis. We evaluated the sensitivity of histology to detect chytrids in 20 wild specimens of 2 frog species from Uruguay that were clinically normal, but confirmed by PCR to be infected by B. dendrobatidis. We detected maturing and sporulated sporangia in 15 of 20 (75%) frogs, which is more sensitive than previously reported for histology. The effort needed to identify chytrids in histologic skin sections of Physalaemus henselii and Pleurodema bibroni required examination of 3.2 and 8.7 mm of skin sections for each frog species, respectively.
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Affiliation(s)
- Claudio Borteiro
- Departamento de Patología, Facultad de Veterinaria (Borteiro, Verdes), Montevideo, Uruguay.,Universidad de la República (UdelaR), Montevideo, Uruguay.,Sección Bioquímica (Martínez Debat), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Departamento de Evolución de Cuencas (Ubilla), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay (Borteiro, Kolenc)
| | - Francisco Kolenc
- Departamento de Patología, Facultad de Veterinaria (Borteiro, Verdes), Montevideo, Uruguay.,Universidad de la República (UdelaR), Montevideo, Uruguay.,Sección Bioquímica (Martínez Debat), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Departamento de Evolución de Cuencas (Ubilla), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay (Borteiro, Kolenc)
| | - José Manuel Verdes
- Departamento de Patología, Facultad de Veterinaria (Borteiro, Verdes), Montevideo, Uruguay.,Universidad de la República (UdelaR), Montevideo, Uruguay.,Sección Bioquímica (Martínez Debat), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Departamento de Evolución de Cuencas (Ubilla), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay (Borteiro, Kolenc)
| | - Claudio Martínez Debat
- Departamento de Patología, Facultad de Veterinaria (Borteiro, Verdes), Montevideo, Uruguay.,Universidad de la República (UdelaR), Montevideo, Uruguay.,Sección Bioquímica (Martínez Debat), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Departamento de Evolución de Cuencas (Ubilla), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay (Borteiro, Kolenc)
| | - Martín Ubilla
- Departamento de Patología, Facultad de Veterinaria (Borteiro, Verdes), Montevideo, Uruguay.,Universidad de la República (UdelaR), Montevideo, Uruguay.,Sección Bioquímica (Martínez Debat), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Departamento de Evolución de Cuencas (Ubilla), Facultad de Ciencias, UdelaR, Montevideo, Uruguay.,Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay (Borteiro, Kolenc)
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76
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Bie J, Liu X, Zhang X, Wang H. Detection and comparative analysis of cutaneous bacterial communities of farmed and wild Rana dybowskii (Amphibia: Anura). THE EUROPEAN ZOOLOGICAL JOURNAL 2019. [DOI: 10.1080/24750263.2019.1683627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Affiliation(s)
- J. Bie
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - X. Liu
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - X. Zhang
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - H. Wang
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
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77
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Bower DS, Brannelly LA, McDonald CA, Webb RJ, Greenspan SE, Vickers M, Gardner MG, Greenlees MJ. A review of the role of parasites in the ecology of reptiles and amphibians. AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Deborah S. Bower
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
- School of Environmental and Rural Science; University of New England; Armidale New South Wales Australia
| | - Laura A. Brannelly
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh Pennsylvania USA
| | - Cait A. McDonald
- Department of Ecology and Evolutionary Biology; Cornell University; Ithaca New York USA
| | - Rebecca J. Webb
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland Australia
| | - Sasha E. Greenspan
- Department of Biological Sciences; University of Alabama; Tuscaloosa Alabama USA
| | - Mathew Vickers
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
| | - Michael G. Gardner
- College of Science and Engineering; Flinders University; Adelaide South Australia Australia
- Evolutionary Biology Unit; South Australian Museum; Adelaide South Australia Australia
| | - Matthew J. Greenlees
- School of Life and Environmental Sciences; University of Sydney; Sydney New South Wales Australia
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78
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Seyedmousavi S, Bosco SDMG, de Hoog S, Ebel F, Elad D, Gomes RR, Jacobsen ID, Jensen HE, Martel A, Mignon B, Pasmans F, Piecková E, Rodrigues AM, Singh K, Vicente VA, Wibbelt G, Wiederhold NP, Guillot J. Fungal infections in animals: a patchwork of different situations. Med Mycol 2018. [PMID: 29538732 DOI: 10.1093/mmy/myx104] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The importance of fungal infections in both human and animals has increased over the last decades. This article represents an overview of the different categories of fungal infections that can be encountered in animals originating from environmental sources without transmission to humans. In addition, the endemic infections with indirect transmission from the environment, the zoophilic fungal pathogens with near-direct transmission, the zoonotic fungi that can be directly transmitted from animals to humans, mycotoxicoses and antifungal resistance in animals will also be discussed. Opportunistic mycoses are responsible for a wide range of diseases from localized infections to fatal disseminated diseases, such as aspergillosis, mucormycosis, candidiasis, cryptococcosis and infections caused by melanized fungi. The amphibian fungal disease chytridiomycosis and the Bat White-nose syndrome are due to obligatory fungal pathogens. Zoonotic agents are naturally transmitted from vertebrate animals to humans and vice versa. The list of zoonotic fungal agents is limited but some species, like Microsporum canis and Sporothrix brasiliensis from cats, have a strong public health impact. Mycotoxins are defined as the chemicals of fungal origin being toxic for warm-blooded vertebrates. Intoxications by aflatoxins and ochratoxins represent a threat for both human and animal health. Resistance to antifungals can occur in different animal species that receive these drugs, although the true epidemiology of resistance in animals is unknown, and options to treat infections caused by resistant infections are limited.
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Affiliation(s)
- Seyedmojtaba Seyedmousavi
- Molecular Microbiology Section, Laboratory of Clinical Microbiology and Immunology (LCMI), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Sandra de M G Bosco
- Department of Microbiology and Immunology, Institute of Biosciences-UNESP Univ Estadual Paulista Botucatu, São Paulo, Brazil
| | - Sybren de Hoog
- Westerdijk Fungal Biodiversity Institute, Utrecht, and Center of Expertise in Mycology of Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Frank Ebel
- Institut für Infektionsmedizin und Zoonosen, Munich, Germany
| | - Daniel Elad
- Department of Clinical Bacteriology and Mycology, Kimron Veterinary Institute, Veterinary Services, Ministry of Agriculture, Beit Dagan, Israel
| | - Renata R Gomes
- Microbiology, Parasitology and Pathology Graduate Programme, Curitiba Department of Basic Pathology, Federal University of Paraná, Curitiba, Brazil
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Hans Knöll Institute, Jena, Germany
| | | | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases. Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Bernard Mignon
- Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, FARAH (Fundamental and Applied Research for Animals & Health), University of Liège, Liège, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases. Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Elena Piecková
- Faculty of Medicine, Slovak Medical University, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia
| | - Anderson Messias Rodrigues
- Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, São Paulo, Brazil
| | - Karuna Singh
- Department of Zoology, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi, India
| | - Vania A Vicente
- Research Group Microbial Immunology, Hans Knöll Institute, Jena, Germany
| | - Gudrun Wibbelt
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Nathan P Wiederhold
- Fungus Testing Laboratory, Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Jacques Guillot
- Department of Parasitology, Mycology and Dermatology, EA Dynamyc UPEC, EnvA, Ecole nationale vétérinaire d'Alfort, Maisons-Alfort, France
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79
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Grogan LF, Robert J, Berger L, Skerratt LF, Scheele BC, Castley JG, Newell DA, McCallum HI. Review of the Amphibian Immune Response to Chytridiomycosis, and Future Directions. Front Immunol 2018; 9:2536. [PMID: 30473694 PMCID: PMC6237969 DOI: 10.3389/fimmu.2018.02536] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/15/2018] [Indexed: 12/27/2022] Open
Abstract
The fungal skin disease, chytridiomycosis (caused by Batrachochytrium dendrobatidis and B. salamandrivorans), has caused amphibian declines and extinctions globally since its emergence. Characterizing the host immune response to chytridiomycosis has been a focus of study with the aim of disease mitigation. However, many aspects of the innate and adaptive arms of this response are still poorly understood, likely due to the wide range of species' responses to infection. In this paper we provide an overview of expected immunological responses (with inference based on amphibian and mammalian immunology), together with a synthesis of current knowledge about these responses for the amphibian-chytridiomycosis system. We structure our review around four key immune stages: (1) the naïve immunocompetent state, (2) immune defenses that are always present (constitutive defenses), (3) mechanisms for recognition of a pathogen threat and innate immune defenses, and (4) adaptive immune responses. We also evaluate the current hot topics of immunosuppression and immunopathology in chytridiomycosis, and discuss their respective roles in pathogenesis. Our synthesis reveals that susceptibility to chytridiomycosis is likely to be multifactorial. Susceptible amphibians appear to have ineffective constitutive and innate defenses, and a late-stage response characterized by immunopathology and Bd-induced suppression of lymphocyte responses. Overall, we identify substantial gaps in current knowledge, particularly concerning the entire innate immune response (mechanisms of initial pathogen detection and possible immunoevasion by Bd, degree of activation and efficacy of the innate immune response, the unexpected absence of innate leukocyte infiltration, and the cause and role of late-stage immunopathology in pathogenesis). There are also gaps concerning most of the adaptive immune system (the relative importance of B and T cell responses for pathogen clearance, the capacity and extent of immunological memory, and specific mechanisms of pathogen-induced immunosuppression). Improving our capacity for amphibian immunological research will require selection of an appropriate Bd-susceptible model species, the development of taxon-specific affinity reagents and cell lines for functional assays, and the application of a suite of conventional and emerging immunological methods. Despite current knowledge gaps, immunological research remains a promising avenue for amphibian conservation management.
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Affiliation(s)
- Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Jacques Robert
- University of Rochester Medical Center, Rochester, NY, United States
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.,Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.,Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Benjamin C Scheele
- Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia.,Threatened Species Recovery Hub, National Environmental Science Program, Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia
| | - J Guy Castley
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
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80
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Kosch TA, Silva CNS, Brannelly LA, Roberts AA, Lau Q, Marantelli G, Berger L, Skerratt LF. Genetic potential for disease resistance in critically endangered amphibians decimated by chytridiomycosis. Anim Conserv 2018. [DOI: 10.1111/acv.12459] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- T. A. Kosch
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - C. N. S. Silva
- Centre for Sustainable Tropical Fisheries and Aquaculture College of Science and Engineering James Cook University Townsville Qld Australia
| | - L. A. Brannelly
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
- Department of Biological Sciences University of Pittsburgh Pittsburgh PA USA
| | - A. A. Roberts
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - Q. Lau
- Department of Evolutionary Studies of Biosystems Sokendai (The Graduate University for Advanced Studies) Hayama Japan
| | | | - L. Berger
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
| | - L. F. Skerratt
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Qld Australia
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81
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Isidoro-Ayza M, Grear DA, Chambouvet A. Pathology and Case Definition of Severe Perkinsea Infection of Frogs. Vet Pathol 2018; 56:133-142. [PMID: 30236039 DOI: 10.1177/0300985818798132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Severe Perkinsea infection (SPI) is an emerging disease of frogs responsible for mass mortalities of tadpoles across the United States. It is caused by protozoa belonging to the phylum Perkinsozoa that form a distinct group referred to as the Pathogenic Perkinsea Clade of frogs. In this work, we provide detailed description of gross and histologic lesions from 178 naturally infected tadpoles, including 10 species from 22 mortality events and 6 amphibian health monitoring studies from diverse geographic areas. On external examination, we observed abdominal distension (10, 5.6%), cutaneous erythema and petechia (3, 1.7%), subcutaneous edema (3, 1.7%), and areas of white skin discoloration (3, 1.7%). On macroscopic examination of internal organs, we found hepatomegaly (68, 38.2%), splenomegaly (51, 28.7%), nephromegaly (47, 26.4%), ascites (15, 8.4%), segmental irregular thickening and white discoloration of the intestine (8, 4.5%), pancreatomegaly (4, 2.2%), and pancreatic petechia (1, 0.6%). Histologically, over 60% of the liver (148/165, 89.7%), kidney (113/147, 76.9%), spleen (96/97, 99%), and pancreas (46/68, 67.6%) were invaded by myriad intracellular and extracellular Perkinsea hypnospore-like and trophozoite-like organisms. Numerous other tissues were affected to a lesser extent. Mild histiocytic inflammation with fewer lymphocytes or eosinophils was commonly observed in areas of infection that were not obscured by lympho-granulocytic hematopoietic tissue. In light of these observations, we suggest a logical pathogenesis sequence. Finally, we propose a "case definition" for SPI to promote standardized communication of results and prevent misdiagnosis with epidemiological and pathologically overlapping diseases such as ranavirosis.
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Affiliation(s)
- Marcos Isidoro-Ayza
- 1 Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.,2 National Wildlife Health Center-US Geological Survey, Madison, WI, USA
| | - Daniel A Grear
- 3 National Wildlife Health Center-US Geological Survey, Madison, WI, USA
| | - Aurélie Chambouvet
- 4 Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Technopole Brest Iroise, Plouzané, France
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82
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Fitzpatrick LD, Pasmans F, Martel A, Cunningham AA. Epidemiological tracing of Batrachochytrium salamandrivorans identifies widespread infection and associated mortalities in private amphibian collections. Sci Rep 2018; 8:13845. [PMID: 30218076 PMCID: PMC6138723 DOI: 10.1038/s41598-018-31800-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/23/2018] [Indexed: 12/17/2022] Open
Abstract
The amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) infects newts and salamanders (urodele amphibians), in which it can cause fatal disease. This pathogen has caused dramatic fire salamander population declines in Belgium, the Netherlands and Germany since its discovery in 2010. Thought to be native to Asia, it has been hypothesised that Bsal was introduced to Europe with the importation of infected amphibians for the commercial pet trade. Following the discovery of Bsal in captive amphibians in the United Kingdom in 2015, we used contact-tracing to identify epidemiologically-linked private amphibian collections in Western Europe. Of 16 linked collections identified, animals were tested from 11 and urodeles tested positive for Bsal in seven, including the identification of the pathogen in Spain for the first time. Mortality of Bsal-positive individuals was observed in five collections. Our results indicate that Bsal is likely widespread within the private amphibian trade, at least in Europe. These findings are important for informing policy regarding Bsal control strategies.
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Affiliation(s)
- Liam D Fitzpatrick
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK.
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83
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Chalkowski K, Lepczyk CA, Zohdy S. Parasite Ecology of Invasive Species: Conceptual Framework and New Hypotheses. Trends Parasitol 2018; 34:655-663. [DOI: 10.1016/j.pt.2018.05.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/22/2018] [Accepted: 05/31/2018] [Indexed: 01/27/2023]
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84
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DeCandia AL, Dobson AP, vonHoldt BM. Toward an integrative molecular approach to wildlife disease. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2018; 32:798-807. [PMID: 29380417 PMCID: PMC7162296 DOI: 10.1111/cobi.13083] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/12/2017] [Accepted: 01/19/2018] [Indexed: 05/03/2023]
Abstract
Pathogens pose serious threats to human health, agricultural investment, and biodiversity conservation through the emergence of zoonoses, spillover to domestic livestock, and epizootic outbreaks. As such, wildlife managers are often tasked with mitigating the negative effects of disease. Yet, parasites form a major component of biodiversity that often persist. This is due to logistical challenges of implementing management strategies and to insufficient understanding of host-parasite dynamics. We advocate for an inclusive understanding of molecular diversity in driving parasite infection and variable host disease states in wildlife systems. More specifically, we examine the roles of genetic, epigenetic, and commensal microbial variation in disease pathogenesis. These include mechanisms underlying parasite virulence and host resistance and tolerance, and the development, regulation, and parasite subversion of immune pathways, among other processes. Case studies of devil facial tumor disease in Tasmanian devils (Sarcophilus harrisii) and chytridiomycosis in globally distributed amphibians exemplify the broad range of questions that can be addressed by examining different facets of molecular diversity. For particularly complex systems, integrative molecular analyses present a promising frontier that can provide critical insights necessary to elucidate disease dynamics operating across scales. These insights enable more accurate risk assessment, reconstruction of transmission pathways, discernment of optimal intervention strategies, and development of more effective and ecologically sound treatments that minimize damage to the host population and environment. Such measures are crucial when mitigating threats posed by wildlife disease to humans, domestic animals, and species of conservation concern.
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Affiliation(s)
- Alexandra L. DeCandia
- Department of Ecology and Evolutionary BiologyPrinceton University106A Guyot HallPrincetonNJ 08544U.S.A.
| | - Andrew P. Dobson
- Department of Ecology and Evolutionary BiologyPrinceton University106A Guyot HallPrincetonNJ 08544U.S.A.
| | - Bridgett M. vonHoldt
- Department of Ecology and Evolutionary BiologyPrinceton University106A Guyot HallPrincetonNJ 08544U.S.A.
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85
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Smith HK, Pasmans F, Dhaenens M, Deforce D, Bonte D, Verheyen K, Lens L, Martel A. Skin mucosome activity as an indicator of Batrachochytrium salamandrivorans susceptibility in salamanders. PLoS One 2018; 13:e0199295. [PMID: 30020936 PMCID: PMC6051575 DOI: 10.1371/journal.pone.0199295] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
Recently emerged fungal diseases, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are an increasing threat to amphibians worldwide. In Europe, the threat of Bsal to salamander populations is demonstrated by the rapid decline of fire salamander populations in Germany, the Netherlands and Belgium. Although most European urodelans are susceptible to infection in infection trials, recent evidence suggests marked interspecific differences in the course of infection, with potentially far reaching implications for salamander conservation. As a salamander's skin is the first line of defense against such pathogens, interspecific differences in innate immune function of the skin may explain differential susceptibility. Here we investigate if compounds present on a salamander's skin can kill Bsal spores and if there is variation among species. We used a non-invasive assay to compare killing ability of salamander mucosomes of four different species (captive and wild Salamandra salamandra and captive Ichtyosaura alpestris, Cynops pyrrhogaster and Lissotriton helveticus) by exposing Bsal zoospores to salamander mucosomes and determining spore survival. In all samples, zoospores were killed when exposed to mucosomes. Moreover, we saw a significant variation in this Bsal killing ability of mucosomes between different salamander host species. Our results indicate that mucosomes of salamanders might provide crucial skin protection against Bsal, and could explain why some species are more susceptible than others. This study represents a step towards better understanding host species variation in innate immune function and disease susceptibility in amphibians.
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Affiliation(s)
- Hannah Keely Smith
- Wildlife Health Ghent, Department of Pathology, Bacteriology & Avian Diseases, Ghent University, Salisburylaan, Merelbeke, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Department of Pathology, Bacteriology & Avian Diseases, Ghent University, Salisburylaan, Merelbeke, Belgium
| | - Maarten Dhaenens
- Laboratory for Pharmaceutical Biotechnology, Ghent University, Faculty of Pharmaceutical Science, Ottergemsesteenweg, Ghent, Belgium
| | - Dieter Deforce
- Laboratory for Pharmaceutical Biotechnology, Ghent University, Faculty of Pharmaceutical Science, Ottergemsesteenweg, Ghent, Belgium
| | - Dries Bonte
- Terrestrial Ecology Unit (TEREC), Department of Biology, Ghent University, K. L. Ledeganckstraat, Ghent, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Environment, Ghent University, Geraardsberge Steenweg, Gontrode, Belgium
| | - Luc Lens
- Terrestrial Ecology Unit (TEREC), Department of Biology, Ghent University, K. L. Ledeganckstraat, Ghent, Belgium
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology & Avian Diseases, Ghent University, Salisburylaan, Merelbeke, Belgium
- * E-mail:
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86
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Karwacki EE, Atkinson MS, Ossiboff RJ, Savage AE. Novel quantitative PCR assay specific for the emerging Perkinsea amphibian pathogen reveals seasonal infection dynamics. DISEASES OF AQUATIC ORGANISMS 2018; 129:85-98. [PMID: 29972369 DOI: 10.3354/dao03239] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Amphibians are suffering from large-scale population declines worldwide, and infectious diseases are a central driving force. Most pathogen-mediated declines are attributed to 2 pathogens, the fungus Batrachochytrium dendrobatidis and iridoviruses in the genus Ranavirus. However, another emerging pathogen within Perkinsea is associated with mass mortality events in anurans throughout the southeastern USA. Molecular resources for detecting amphibian Perkinsea have been limited to general protistan primers that amplify a range of organisms, not all of which are disease agents. Moreover, the only quantitative method available involves histopathology, which is labor intensive, requires destructive sampling, and lacks sensitivity. Here, we developed a novel quantitative (q)PCR assay that is sensitive and specific for amphibian Perkinsea, providing a resource for rapid and reliable pathogen diagnosis. We used histopathology to confirm that qPCR burdens track the severity of Perkinsea infections across multiple anuran tissues. We also sampled 3 natural amphibian communities in Florida, USA, to assess the prevalence and intensity of amphibian Perkinsea infections across species, seasons, tissues, and life stages. Anurans from 2 of 3 sampling locations were infected, totaling 25.1% of all individuals. Infection prevalence varied significantly among locations, seasons, species, and life stages. Infection intensity was significantly higher in larval tissues than adult tissues, and was significantly different across locations, seasons, and species. Understanding relationships between amphibian Perkinsea infection, other pathogens, and biotic and abiotic cofactors will allow us to assess what drives population declines, improving our ability to develop conservation strategies for susceptible species to reduce global amphibian biodiversity loss.
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Affiliation(s)
- Emily E Karwacki
- University of Central Florida, Department of Biology, 4110 Libra Dr., Orlando, Florida 32816, USA
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87
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Grueber C, Fox S, Belov K, Pemberton D, Hogg C. Landscape-level field data reveal broad-scale effects of a fatal, transmissible cancer on population ecology of the Tasmanian devil. Mamm Biol 2018. [DOI: 10.1016/j.mambio.2018.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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88
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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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89
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Chytridiomycosis causes catastrophic organism-wide metabolic dysregulation including profound failure of cellular energy pathways. Sci Rep 2018; 8:8188. [PMID: 29844538 PMCID: PMC5974026 DOI: 10.1038/s41598-018-26427-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/08/2018] [Indexed: 02/07/2023] Open
Abstract
Chytridiomycosis is among several recently emerged fungal diseases of wildlife that have caused decline or extinction of naïve populations. Despite recent advances in understanding pathogenesis, host response to infection remains poorly understood. Here we modelled a total of 162 metabolites across skin and liver tissues of 61 frogs from four populations (three long-exposed and one naïve to the fungus) of the Australian alpine tree frog (Litoria verreauxii alpina) throughout a longitudinal exposure experiment involving both infected and negative control individuals. We found that chytridiomycosis dramatically altered the organism-wide metabolism of clinically diseased frogs. Chytridiomycosis caused catastrophic failure of normal homeostatic mechanisms (interruption of biosynthetic and degradation metabolic pathways), and pronounced dysregulation of cellular energy metabolism. Key intermediates of the tricarboxylic acid cycle were markedly depleted, including in particular α-ketoglutarate and glutamate that together constitute a key nutrient pathway for immune processes. This study was the first to apply a non-targeted metabolomics approach to a fungal wildlife disease and specifically to dissect the host-pathogen interface of Bd-infected frogs. The patterns of metabolite accumulation we have identified reveal whole-body metabolic dysfunction induced by a fungal skin infection, and these findings have broad relevance for other fungal diseases.
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90
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Baugh AT, Bastien B, Still MB, Stowell N. Validation of water-borne steroid hormones in a tropical frog (Physalaemus pustulosus). Gen Comp Endocrinol 2018; 261:67-80. [PMID: 29397994 DOI: 10.1016/j.ygcen.2018.01.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/18/2022]
Abstract
Minimally invasive methods for estimating hormone concentrations in wild vertebrates offer the opportunity to repeatedly measure behavior and hormone concentrations within individuals while minimizing experimenter interference during sample collection. We examined three steroid hormones (corticosterone, CORT; 17-β estradiol, E2; progesterone, PROG) in túngara frogs (Physalaemus pustulosus) using non-invasive water-borne methods. Using solid-phase extraction of water samples and liquid extraction of plasma and homogenate samples, coupled with enzyme immunoassays, we complimented the conventional validation approaches (parallelism, recovery determination) with dose-response assays that incorporated pharmacological challenges with adrenocorticotropic hormone (ACTH) and human chorionic gonadotropin (HCG). We also compared steroid concentrations in water to those observed in plasma and whole body homogenates. Lastly, we identified the constituent steroids in each sample type with a panel targeting 30 steroid species using high performance liquid chromatography-mass spectrometry (HPLC-MS). We found that a 60-min water-bath captures physiologically relevant changes in concentrations of CORT, E2 and PROG. Peak levels of water-borne CORT were found at approximately 2 h after ACTH injection. Water-borne CORT and E2 concentrations were positively correlated with their plasma and homogenate equivalents, while water-borne PROG was uncorrelated with homogenate PROG concentrations but negatively correlated with homogenate E2 concentrations. Together, our findings indicate that sampling water-borne hormones presents a non-invasive and biologically informative approach that will be useful for behavioral endocrinologists and conservation physiologists.
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Affiliation(s)
- Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
| | - Brandon Bastien
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
| | - Meghan B Still
- Department of Integrative Biology, The University of Texas at Austin, 1 University Station, C0930, Austin, TX 78712, USA
| | - Nicole Stowell
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
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91
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Wu NC, Cramp RL, Franklin CE. Body size influences energetic and osmoregulatory costs in frogs infected with Batrachochytrium dendrobatidis. Sci Rep 2018; 8:3739. [PMID: 29487313 PMCID: PMC5829222 DOI: 10.1038/s41598-018-22002-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/06/2018] [Indexed: 12/18/2022] Open
Abstract
Sloughing maintains the skins integrity and critical functionality in amphibians. Given the behavioural, morphological and osmoregulatory changes that accompany sloughing, this process is likely to be physiologically costly. Chytridiomycosis, a cutaneous disease of amphibians caused by the fungus Batrachochytrium dendrobatidis (Bd), disrupts skin function and increases sloughing rates. Moreover, mortality rates from chytridiomycosis are significantly higher in juveniles and so we hypothesised that smaller individuals maybe more susceptible to chytridiomycosis because of allometric scaling effects on the energetic and osmoregulatory costs of sloughing. We measured in-vivo cutaneous ion loss rates and whole animal metabolic rate (MR) of Green tree frogs, Litoria caerulea, over a range of body sizes both infected and uninfected frogs during sloughing. Infected animals had a greater rate of ion loss and mass-specific MR during non-sloughing periods but there were no additional effects of sloughing on either of these parameters. There were also significant interactions with body size and Bd load indicating that smaller animals with higher Bd loads have greater rates of ion loss and higher energetic demands. Our results shed light on why smaller Bd-infected anurans often exhibit greater physiological disruption than larger individuals.
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Affiliation(s)
- Nicholas C Wu
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia.
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92
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Eskew EA, Shock BC, LaDouceur EEB, Keel K, Miller MR, Foley JE, Todd BD. Gene expression differs in susceptible and resistant amphibians exposed to Batrachochytrium dendrobatidis. ROYAL SOCIETY OPEN SCIENCE 2018; 5:170910. [PMID: 29515828 PMCID: PMC5830717 DOI: 10.1098/rsos.170910] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Chytridiomycosis, the disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), has devastated global amphibian biodiversity. Nevertheless, some hosts avoid disease after Bd exposure even as others experience near-complete extirpation. It remains unclear whether the amphibian adaptive immune system plays a role in Bd defence. Here, we describe gene expression in two host species-one susceptible to chytridiomycosis and one resistant-following exposure to two Bd isolates that differ in virulence. Susceptible wood frogs (Rana sylvatica) had high infection loads and mortality when exposed to the more virulent Bd isolate but lower infection loads and no fatal disease when exposed to the less virulent isolate. Resistant American bullfrogs (R. catesbeiana) had high survival across treatments and rapidly cleared Bd infection or avoided infection entirely. We found widespread upregulation of adaptive immune genes and downregulation of important metabolic and cellular maintenance components in wood frogs after Bd exposure, whereas American bullfrogs showed little gene expression change and no evidence of an adaptive immune response. Wood frog responses suggest that adaptive immune defences may be ineffective against virulent Bd isolates that can cause rapid physiological dysfunction. By contrast, American bullfrogs exhibited robust resistance to Bd that is likely attributable, at least in part, to their continued upkeep of metabolic and skin integrity pathways as well as greater antimicrobial peptide expression compared to wood frogs, regardless of exposure. Greater understanding of these defences will ultimately help conservationists manage chytridiomycosis.
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Affiliation(s)
- Evan A. Eskew
- Graduate Group in Ecology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
- EcoHealth Alliance, 460 West 34th Street – 17th Floor, New York, NY 10001, USA
- Author for correspondence: Evan A. Eskew e-mail:
| | - Barbara C. Shock
- Department of Biology, Lincoln Memorial University, 6965 Cumberland Gap Parkway, Harrogate, TN 37752, USA
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | | | - Kevin Keel
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Michael R. Miller
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Janet E. Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Brian D. Todd
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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93
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Thomas V, Blooi M, Van Rooij P, Van Praet S, Verbrugghe E, Grasselli E, Lukac M, Smith S, Pasmans F, Martel A. Recommendations on diagnostic tools for Batrachochytrium salamandrivorans. Transbound Emerg Dis 2018; 65:e478-e488. [PMID: 29341499 DOI: 10.1111/tbed.12787] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Indexed: 02/05/2023]
Abstract
Batrachochytrium salamandrivorans (Bsal) poses a major threat to amphibian, and more specifically caudata, diversity. Bsal is currently spreading through Europe, and mitigation measures aimed at stopping its spread and preventing its introduction into naïve environments are urgently needed. Screening for presence of Bsal and diagnosis of Bsal-induced disease in amphibians are essential core components of effective mitigation plans. Therefore, the aim of this study was to present an overview of all Bsal diagnostic tools together with their limitations and to suggest guidelines to allow uniform interpretation. Here, we investigate the use of different diagnostic tools in post-mortem detection of Bsal and whether competition between Bd and Bsal occurs in the species-specific Bd and Bsal duplex real-time PCR. We also investigate the diagnostic sensitivity, diagnostic specificity and reproducibility of the Bsal real-time PCR and show the use of immunohistochemistry in diagnosis of Bsal-induced chytridiomycosis in amphibian samples stored in formaldehyde. Additionally, we have drawn up guidelines for the use and interpretation of the different diagnostic tools for Bsal currently available, to facilitate standardization of execution and interpretation.
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Affiliation(s)
- V Thomas
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - M Blooi
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - P Van Rooij
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - S Van Praet
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - E Verbrugghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - E Grasselli
- Dipartimento di Scienze della Terra, dell'Ambiente e della Vita, DISTAV, Universita di Genova, Genova, Italy
| | - M Lukac
- Department of Poultry Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia
| | - S Smith
- Department of Integrative Biology and Evolution, University of Veterinary Medicine, Vienna, Austria
| | - F Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - A Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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94
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Leary CJ, Ralicki HF, Laurencio D, Crocker-Buta S, Malone JH. Assessing the links among environmental contaminants, endocrinology, and parasites to understand amphibian declines in montane regions of Costa Rica. PLoS One 2018; 13:e0191183. [PMID: 29324824 PMCID: PMC5764372 DOI: 10.1371/journal.pone.0191183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/31/2017] [Indexed: 11/24/2022] Open
Abstract
Amphibians inhabiting montane riparian zones in the Neotropics are particularly vulnerable to decline, but the reasons are poorly understood. Because environmental contaminants, endocrine disruption, and pathogens often figure prominently in amphibian declines it is imperative that we understand how these factors are potentially interrelated to affect montane populations. One possibility is that increased precipitation associated with global warming promotes the deposition of contaminants in montane regions. Increased exposure to contaminants, in turn, potentially elicits chronic elevations in circulating stress hormones that could contribute to montane population declines by compromising resistance to pathogens and/or production of sex steroids regulating reproduction. Here, we test this hypothesis by examining contaminant levels, stress and sex steroid levels, and nematode abundances in male drab treefrogs, Smilisca sordida, from lowland and montane populations in Costa Rica. We found no evidence that montane populations were more likely to possess contaminants (i.e., organochlorine, organophosphate and carbamate pesticides or benzidine and chlorophenoxy herbicides) than lowland populations. We also found no evidence of elevational differences in circulating levels of the stress hormone corticosterone, estradiol or progesterone. However, montane populations possessed lower androgen levels, hosted more nematode species, and had higher nematode abundances than lowland populations. Although these results suggested that nematodes contributed to lower androgens in montane populations, we were unable to detect a significant inverse relationship between nematode abundance and androgen level. Our results suggest that montane populations of this species are not at greater risk of exposure to contaminants or chronic stress, but implicate nematodes and compromised sex steroid levels as potential threats to montane populations.
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Affiliation(s)
- Christopher J. Leary
- University of Mississippi, Department of Biology, University, Mississippi, United States of America
| | - Hannah F. Ralicki
- University of Connecticut, Department of Ecology & Evolutionary Biology, Storrs, Connecticut, United States of America
| | - David Laurencio
- Auburn University Museum of Natural History, Department of Biological Sciences, Auburn, Alabama, United States of America
| | - Sarah Crocker-Buta
- University of Mississippi, Department of Biology, University, Mississippi, United States of America
| | - John H. Malone
- University of Connecticut, Institute of Systems Genomics and Department of Molecular and Cell Biology, Storrs, Connecticut, United States of America
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95
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Williams CL, Caraballo-Rodríguez AM, Allaband C, Zarrinpar A, Knight R, Gauglitz JM. Wildlife-microbiome interactions and disease: exploring opportunities for disease mitigation across ecological scales. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.ddmod.2019.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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96
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Cramp RL, Franklin CE. Exploring the link between ultraviolet B radiation and immune function in amphibians: implications for emerging infectious diseases. CONSERVATION PHYSIOLOGY 2018; 6:coy035. [PMID: 29992023 PMCID: PMC6022628 DOI: 10.1093/conphys/coy035] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/27/2018] [Accepted: 06/07/2018] [Indexed: 05/07/2023]
Abstract
Amphibian populations the world over are under threat of extinction, with as many as 40% of assessed species listed as threatened under IUCN Red List criteria (a significantly higher proportion than other vertebrate group). Amongst the key threats to amphibian species is the emergence of novel infectious diseases, which have been implicated in the catastrophic amphibian population declines and extinctions seen in many parts of the world. The recent emergence of these diseases coincides with increased ambient levels of ultraviolet B radiation (UVBR) due to anthropogenic thinning of the Earth's protective ozone layer, raising questions about potential interactions between UVBR exposure and disease in amphibians. While reasonably well documented in other vertebrate groups (particularly mammals), the immunosuppressive capacity of UVBR and the potential for it to influence disease outcomes has been largely overlooked in amphibians. Herein, we review the evidence for UVBR-associated immune system disruption in amphibians and identify a number of direct and indirect pathways through which UVBR may influence immune function and disease susceptibility in amphibians. By exploring the physiological mechanisms through which UVBR may affect host immune function, we demonstrate how ambient UVBR could increase amphibian susceptibility to disease. We conclude by discussing the potential implications of elevated UVBR for inter and intraspecific differences in disease dynamics and discuss how future research in this field may be directed to improve our understanding of the role that UVBR plays in amphibian immune function.
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Affiliation(s)
- Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland, Australia
- Corresponding author: School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland 4072, Australia.
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland, Australia
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97
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Gauberg J, Wu N, Cramp RL, Kelly SP, Franklin CE. A lethal fungal pathogen directly alters tight junction proteins in the skin of a susceptible amphibian. J Exp Biol 2018; 222:jeb.192245. [DOI: 10.1242/jeb.192245] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 12/05/2018] [Indexed: 01/01/2023]
Abstract
Bacterial and viral pathogens can weaken epithelial barriers by targeting and disrupting tight junction (TJ) proteins. Comparatively, however, little is known about the direct effects of fungal pathogens on TJ proteins and their expression. The disease, chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is threatening amphibian populations worldwide. Bd is known to infect amphibian skin and disrupt cutaneous osmoregulation. However, exactly how this occurs is poorly understood. This study considered the impact of Bd infection on the barrier properties of the Australian green tree frog (Litoria caerulea) epidermis by examining how inoculation of animals with Bd influenced the paracellular movement of FITC-dextran (4 kDa, FD-4) across the skin in association with alterations in the mRNA and protein abundance of select TJ proteins of the epidermal TJ complex. It was observed that Bd infection increased paracellular movement of FD-4 across the skin linearly with fungal infection load. In addition, Bd infection increased transcript abundance of the tricellular TJ (tTJ) protein tricellulin (tric) as well as the bicellular TJ (bTJ) proteins occludin (ocln), claudin (cldn) -1, -4 and the scaffolding TJ protein zonula occludens-1 (zo-1). However, while Tric protein abundance increased in accord with changes in transcript abundance, protein abundance of Cldn-1 was significantly reduced and Ocln protein abundance was unchanged. Data indicate that disruption of cutaneous osmoregulation in L. caerulea following Bd infection occurs, at least in part, by an increase in epidermal paracellular permeability in association with compromised integrity of the epidermal TJ complex.
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Affiliation(s)
- J. Gauberg
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
- Department of Biology, York University, Toronto, ON, Canada
| | - N. Wu
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - R. L. Cramp
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - S. P. Kelly
- Department of Biology, York University, Toronto, ON, Canada
| | - C. E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
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98
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Khanna K, Mishra KP, Ganju L, Kumar B, Singh SB. High-Altitude-Induced alterations in Gut-Immune Axis: A review. Int Rev Immunol 2017; 37:119-126. [PMID: 29231767 DOI: 10.1080/08830185.2017.1407763] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
High-altitude sojourn above 8000 ft is increasing day by day either for pilgrimage, mountaineering, holidaying or for strategic reasons. In India, soldiers are deployed to these high mountains for their duty or pilgrims visit to the holy places, which are located at very high altitude. A large population also resides permanently in high altitude regions. Every year thousands of pilgrims visit Holy cave of Shri Amarnath ji, which is above 15 000 ft. The poor acclimatization to high altitude may cause alteration in immunity. The low oxygen partial pressure may cause alterations in gut microbiota, which may cause changes in gut immunity. Effect of high altitude on gut-associated mucosal system is new area of research. Many studies have been carried out to understand the physiology and immunology behind the high-altitude-induced gut problems. Few interventions have also been discovered to circumvent the problems caused due to high-altitude conditions. In this review, we have discussed the effects of high-altitude-induced changes in gut immunity particularly peyer's patches, NK cells and inflammatory cytokines, secretary immunoglobulins and gut microbiota. The published articles from PubMed and Google scholar from year 1975 to 2017 on high-altitude hypoxia and gut immunity are cited in this review.
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Affiliation(s)
- Kunjan Khanna
- a Immunomodulation Division , Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO , Delhi , India
| | - K P Mishra
- a Immunomodulation Division , Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO , Delhi , India
| | - Lilly Ganju
- a Immunomodulation Division , Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO , Delhi , India
| | - Bhuvnesh Kumar
- a Immunomodulation Division , Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO , Delhi , India
| | - Shashi Bala Singh
- a Immunomodulation Division , Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO , Delhi , India
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99
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Yap TA, Nguyen NT, Serr M, Shepack A, Vredenburg VT. Batrachochytrium salamandrivorans and the Risk of a Second Amphibian Pandemic. ECOHEALTH 2017; 14:851-864. [PMID: 29147975 DOI: 10.1007/s10393-017-1278-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/07/2017] [Accepted: 08/07/2017] [Indexed: 06/07/2023]
Abstract
Amphibians are experiencing devastating population declines globally. A major driver is chytridiomycosis, an emerging infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Bd was described in 1999 and has been linked with declines since the 1970s, while Bsal is a more recently discovered pathogen that was described in 2013. It is hypothesized that Bsal originated in Asia and spread via international trade to Europe, where it has been linked to salamander die-offs. Trade in live amphibians thus represents a significant threat to global biodiversity in amphibians. We review the current state of knowledge regarding Bsal and describe the risk of Bsal spread. We discuss regional responses to Bsal and barriers that impede a rapid, coordinated global effort. The discovery of a second deadly emerging chytrid fungal pathogen in amphibians poses an opportunity for scientists, conservationists, and governments to improve global biosecurity and further protect humans and wildlife from a growing number of emerging infectious diseases.
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Affiliation(s)
- Tiffany A Yap
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Avenue, San Francisco, CA, 94132, USA.
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA.
| | - Natalie T Nguyen
- U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA
| | - Megan Serr
- Department of Biological Sciences, North Carolina State University, Thomas Hall, 1100 Brooks Avenue, Raleigh, NC, 27695, USA
| | - Alexander Shepack
- Zoology Department, Southern Illinois University Carbondale, 1125 Lincoln Drive, Carbondale, IL, 62901, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA
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100
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Greenspan SE, Bower DS, Webb RJ, Berger L, Rudd D, Schwarzkopf L, Alford RA. White blood cell profiles in amphibians help to explain disease susceptibility following temperature shifts. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 77:280-286. [PMID: 28870450 DOI: 10.1016/j.dci.2017.08.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Temperature variability, and in particular temperature decreases, can increase susceptibility of amphibians to infections by the fungus Batrachochytrium dendrobatidis (Bd). However, the effects of temperature shifts on the immune systems of Bd-infected amphibians are unresolved. We acclimated frogs to 16 °C and 26 °C (baseline), simultaneously transferred them to an intermediate temperature (21 °C) and inoculated them with Bd (treatment), and tracked their infection levels and white blood cell profiles over six weeks. Average weekly infection loads were consistently higher in 26°C-history frogs, a group that experienced a 5 °C temperature decrease, than in 16°C-history frogs, a group that experienced a 5 °C temperature increase, but this pattern only approached statistical significance. The 16°C-acclimated frogs had high neutrophil:lymphocyte (N:L) ratios (suggestive of a hematopoietic stress response) at baseline, which were conserved post-treatment. In contrast, the 26°C-acclimated frogs had low N:L ratios at baseline which reversed to high N:L ratios post-treatment (suggestive of immune system activation). Our results suggest that infections were less physiologically taxing for the 16°C-history frogs than the 26°C-history frogs because they had already adjusted immune parameters in response to challenging conditions (cold). Our findings provide a possible mechanistic explanation for observations that amphibians are more susceptible to Bd infection following temperature decreases compared to increases and underscore the consensus that increased temperature variability associated with climate change may increase the impact of infectious diseases.
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Affiliation(s)
- Sasha E Greenspan
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
| | - Deborah S Bower
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Donna Rudd
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lin Schwarzkopf
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Ross A Alford
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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