1
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Holmes ML, Shine R, Waddle AW. Spontaneous reoccurrence of Batrachochytrium dendrobatidis infections in Australian green tree frogs (Litoria caerulea) following apparently successful heat therapy: Case report. Vet Res Commun 2024:10.1007/s11259-024-10449-2. [PMID: 38951465 DOI: 10.1007/s11259-024-10449-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/23/2024] [Indexed: 07/03/2024]
Abstract
Heat therapy has been reported as a safe, effective, and readily available treatment method for heat-tolerant frogs infected with Batrachochytrium dendrobatidis (Bd). We treated wild-caught Australian green tree frogs (Litoria caerulea) infected with Bd using two periods of elevated ambient room temperature (28.2-30.3 °C for 7 weeks followed by 28.9-34.1 °C for 4 weeks). Frogs exhibited persistent and even increasing infection loads in the first treatment period despite prolonged exposure to elevated temperatures, likely due to the presence of cooler microenvironments within their enclosure (25.5-27.0 °C). All frogs eventually returned negative qPCR tests for Bd at the end of the second treatment period, but detectable infections reoccurred one month after frogs were returned to standard housing temperatures (21.2-28.7 °C). Our findings suggest that elevated ambient temperature alone might not eliminate Bd in vivo but can reduce infections loads such that they are undetectable by qPCR analysis of skin swabs. Additional factors, such as cooler microenvironments within enclosures or relative humidity, may influence the success of heat therapy. We recommend further research into the combined effects of temperature and humidity during heat therapy and emphasize the importance of accurate temperature measurements as well as post-treatment monitoring at Bd-permissive temperatures to confirm successful clearance of infections.
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Affiliation(s)
- Madeleine L Holmes
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Richard Shine
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Anthony W Waddle
- Applied Biosciences, Macquarie University, Sydney, NSW, Australia
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2
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Jadwani-Bungar T, Doidge NP, Wallace DK, Brannelly LA. Baseline haematological parameters in three common Australian frog species. PeerJ 2024; 12:e17406. [PMID: 38860213 PMCID: PMC11164059 DOI: 10.7717/peerj.17406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 04/25/2024] [Indexed: 06/12/2024] Open
Abstract
Amphibians are experiencing declines globally, with emerging infectious diseases as one of the main causes. Haematological parameters present a useful method for determining the health status of animals and the effects of particular diseases, but the interpretation of differential cell counts relies on knowing the normal ranges for the species and factors that can affect these counts. However, there is very little data on either normal haematological parameters or guides for blood cell types for free-ranging frog species across the world. This study aims to 1) create a visual guide for three different Australian frog species: Litoria paraewingi, Limnodynastes dumerilii, and Crinia signifera, 2) determine the proportions of erythrocytes to leukocytes and 3) differential leukocytes within blood smears from these three species and 4) assess the association between parasites and differential counts. We collected blood samples from free-ranging frogs and analysed blood smears. We also looked for ectoparasites and tested for the fungal disease chytridiomycosis. Overall, we found that the differentials of erythrocytes to leukocytes were not affected by species, but the proportions of different leukocytes did vary across species. For example, while lymphocytes were the most common type of leukocyte across the three species, eosinophils were relatively common in Limnodynastes dumerilii but rarely present in the other two species. We noted chytridiomycosis infection as well as ectoparasites present in some individuals but found no effect of parasites on blood parameters. Our results add baseline haematological parameters for three Australian frog species and provide an example of how different frog species can vary in their differential blood cell counts. More information is needed on frog haematological data before these parameters can be used to determine the health status of wild or captive frogs.
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Affiliation(s)
- Tara Jadwani-Bungar
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Nicholas P. Doidge
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Danielle K. Wallace
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Laura A. Brannelly
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
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3
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Berger L, Skerratt LF, Kosch TA, Brannelly LA, Webb RJ, Waddle AW. Advances in Managing Chytridiomycosis for Australian Frogs: Gradarius Firmus Victoria. Annu Rev Anim Biosci 2024; 12:113-133. [PMID: 38358840 DOI: 10.1146/annurev-animal-021122-100823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Extensive knowledge gains from research worldwide over the 25 years since the discovery of chytridiomycosis can be used for improved management. Strategies that have saved populations in the short term and/or enabled recovery include captive breeding, translocation into disease refugia, translocation from resistant populations, disease-free exclosures, and preservation of disease refuges with connectivity to previous habitat, while antifungal treatments have reduced mortality rates in the wild. Increasing host resistance is the goal of many strategies under development, including vaccination and targeted genetic interventions. Pathogen-directed strategies may be more challenging but would have broad applicability. While the search for the silver bullet solution continues, we should value targeted local interventions that stop extinction and buy time for evolution of resistance or development of novel solutions. As for most invasive species and infectious diseases, we need to accept that ongoing management is necessary. For species continuing to decline, proactive deployment and assessment of promising interventions are more valid than a hands-off, do-no-harm approach that will likely allow further extinctions.
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Affiliation(s)
- Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Tiffany A Kosch
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Laura A Brannelly
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Rebecca J Webb
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Anthony W Waddle
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
- Applied Biosciences, Macquarie University, Sydney, New South Wales, Australia;
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4
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Farquharson KA, McLennan EA, Belov K, Hogg CJ. The genome sequence of the critically endangered Kroombit tinkerfrog ( Taudactylus pleione). F1000Res 2023; 12:845. [PMID: 37663197 PMCID: PMC10474343 DOI: 10.12688/f1000research.138571.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/10/2023] [Indexed: 09/05/2023] Open
Abstract
The Kroombit tinkerfrog ( Taudactylus pleione) is a stream-dwelling amphibian of the Myobatrachidae family. It is listed as Critically Endangered and is at high risk of extinction due to chytridiomycosis. Here, we provide the first genome assembly of the evolutionarily distinct Taudactylus genus. We sequenced PacBio HiFi reads to assemble a high-quality long-read genome and identified the mitochondrial genome. We also generated a global transcriptome from a tadpole to improve gene annotation. The genome was 5.52 Gb in length and consisted of 4,196 contigs with a contig N50 of 8.853 Mb and an L50 of 153. This study provides the first genomic resources for the Kroombit tinkerfrog to assist in future phylogenetic, environmental DNA, conservation breeding, and disease susceptibility studies.
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Affiliation(s)
- Katherine A. Farquharson
- The University of Sydney, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Sydney, New South Wales, 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Elspeth A. McLennan
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Katherine Belov
- The University of Sydney, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Sydney, New South Wales, 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Carolyn J. Hogg
- The University of Sydney, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Sydney, New South Wales, 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, 2006, Australia
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5
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Mollard R, Mahony M. Cell culture and karyotypic description of Pseudophrynecoriacea (Keferstein, 1868) (Amphibia, Anura) from the New South Wales Central Coast. COMPARATIVE CYTOGENETICS 2023; 17:263-272. [PMID: 38026094 PMCID: PMC10656613 DOI: 10.3897/compcytogen.17.113526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023]
Abstract
The karyotype of the IUCN least concern red-backed toadlet Pseudophryne (P.) coriacea (Keferstein, 1868) from the New South Wales Central Coast is described following tissue culture of toe clipping macerates and conventional DAPI staining. The diploid number is 2n = 24. The karyotype is represented by six large and five small chromosomal pairs and one very small chromosomal pair. The very small chromosome 12 is 12% the size of chromosome 1. One of the large chromosomes is subtelocentric, two of the large chromosomes are submetacentric and the remaining chromosomes are metacentric. The putative nucleolus organiser region (NOR) is observed on chromosome 4. The diploid number and location of the putative NOR correlates to that of the previously published IUCN critically endangered P.corroboree (Moore 1953) and unpublished descriptions of the P.coriacea karyotype. This is the first described cell culture of a species from the genus Pseudophryne Fitzinger, 1843, first published analysis of the P.coriacea karyotype and the first published analysis of centromeric allocation of this genus. Globally there exists a large inventory of tissue samples in cryobanks that are not associated with known recovery mechanisms such as basic cell culture techniques. Detailed cytogenetic analyses of these cryobanked samples are therefore not possible. This work therefore enables: (i) a comparison of the P.coriacea karyotype with that of the critically endangered P.corroboree and (ii) a benchmark for repeat and future cytogenetic and genomic analyses of cryostored samples of this genus.
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Affiliation(s)
- Richard Mollard
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, 3052, AustraliaThe University of MelbourneMelbourneAustralia
- Amphicell Pty Ltd, Cairns, Queensland, AustraliaAmphicell Pty LtdCairnsAustralia
| | - Michael Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308, AustraliaUniversity of NewcastleCallaghanAustralia
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6
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Scheele BC, Heard GW, Cardillo M, Duncan RP, Gillespie GR, Hoskin CJ, Mahony M, Newell D, Rowley JJL, Sopniewski J. An invasive pathogen drives directional niche contractions in amphibians. Nat Ecol Evol 2023; 7:1682-1692. [PMID: 37550511 DOI: 10.1038/s41559-023-02155-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/07/2023] [Indexed: 08/09/2023]
Abstract
Global change is causing an unprecedented restructuring of ecosystems, with the spread of invasive species being a key driver. While population declines of native species due to invasives are well documented, much less is known about whether new biotic interactions reshape niches of native species. Here we quantify geographic range and realized-niche contractions in Australian frog species following the introduction of amphibian chytrid fungus Batrachochytrium dendrobatidis, a pathogen responsible for catastrophic amphibian declines worldwide. We show that chytrid-impacted species experienced proportionately greater contractions in niche breadth than geographic distribution following chytrid emergence. Furthermore, niche contractions were directional, with contemporary distributions of chytrid-impacted species characterized by higher temperatures, lower diurnal temperature range, higher precipitation and lower elevations. Areas with these conditions may enable host persistence with chytrid through lower pathogenicity of the fungus and/or greater demographic resilience. Nevertheless, contraction to a narrower subset of environmental conditions could increase host vulnerability to other threatening processes and should be considered in assessments of extinction risk and during conservation planning. More broadly, our results emphasize that biotic interactions can strongly shape species realized niches and that large-scale niche contractions due to new species interactions-particularly emerging pathogens-could be widespread.
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Affiliation(s)
- Ben C Scheele
- Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia.
- Macroevolution and Macroecology Group, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
| | - Geoffrey W Heard
- Terrestrial Ecosystem Research Network and Centre for Biodiversity and Conservation Science, University of Queensland, Brisbane, Queensland, Australia
| | - Marcel Cardillo
- Macroevolution and Macroecology Group, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Richard P Duncan
- Centre for Conservation Ecology and Genomics, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Graeme R Gillespie
- Science, Economics and Insights Division, Department of Planning and Environment, Parramatta, New South Wales, Australia
- School of Biosciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Conrad J Hoskin
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Michael Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
| | - David Newell
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Jodi J L Rowley
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
- Centre for Ecosystem Science; School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jarrod Sopniewski
- Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, Australia
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7
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Nolan N, Hayward MW, Klop-Toker K, Mahony M, Lemckert F, Callen A. Complex Organisms Must Deal with Complex Threats: How Does Amphibian Conservation Deal with Biphasic Life Cycles? Animals (Basel) 2023; 13:ani13101634. [PMID: 37238064 DOI: 10.3390/ani13101634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/08/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
The unprecedented rate of global amphibian decline is attributed to The Anthropocene, with human actions triggering the Sixth Mass Extinction Event. Amphibians have suffered some of the most extreme declines, and their lack of response to conservation actions may reflect challenges faced by taxa that exhibit biphasic life histories. There is an urgent need to ensure that conservation measures are cost-effective and yield positive outcomes. Many conservation actions have failed to meet their intended goals of bolstering populations to ensure the persistence of species into the future. We suggest that past conservation efforts have not considered how different threats influence multiple life stages of amphibians, potentially leading to suboptimal outcomes for their conservation. Our review highlights the multitude of threats amphibians face at each life stage and the conservation actions used to mitigate these threats. We also draw attention to the paucity of studies that have employed multiple actions across more than one life stage. Conservation programs for biphasic amphibians, and the research that guides them, lack a multi-pronged approach to deal with multiple threats across the lifecycle. Conservation management programs must recognise the changing threat landscape for biphasic amphibians to reduce their notoriety as the most threatened vertebrate taxa globally.
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Affiliation(s)
- Nadine Nolan
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Matthew W Hayward
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Kaya Klop-Toker
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Michael Mahony
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Frank Lemckert
- Eco Logical Australia Pty Ltd., Perth, WA 6000, Australia
| | - Alex Callen
- Conservation Science Research Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
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8
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Zumbado-Ulate H, Neam K, García-Rodríguez A, Ochoa-Ochoa L, Chaves G, Kolby JE, Granados-Martínez S, Hertz A, Bolaños F, Ariano-Sánchez D, Puschendorf R, Searle CL. Ecological correlates of extinction risk and persistence of direct-developing stream-dwelling frogs in Mesoamerica. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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9
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Carver S, Peters A, Richards SA. Model Integrated Disease Management to facilitate effective translatable solutions for wildlife disease issues. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Scott Carver
- Department of Biological Sciences University of Tasmania
| | - Andrew Peters
- School of Animal and Veterinary Sciences Charles Sturt University
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10
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Besedin D, Turner BJ, Deo P, Lopes MDB, Williams CR. Effect of captivity and water salinity on culture-dependent frog skin microbiota and Batrachochytrium dendrobatidis ( Bd) infection. T ROY SOC SOUTH AUST 2022. [DOI: 10.1080/03721426.2022.2086358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Darislav Besedin
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Brandon J. Turner
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Permal Deo
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
- Health and Biomedical Innovation, UniSA Clinical and Health Science, University of South Australia, Adelaide, South Australia, Australia
| | - Miguel De Barros Lopes
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
- Health and Biomedical Innovation, UniSA Clinical and Health Science, University of South Australia, Adelaide, South Australia, Australia
| | - Craig R. Williams
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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11
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Sopniewski J, Scheele BC, Cardillo M. Predicting the distribution of Australian frogs and their overlap with
Batrachochytrium dendrobatidis
under climate change. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Jarrod Sopniewski
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
- School of Biological Sciences The University of Western Australia Crawley Western Australia Australia
| | - Benjamin C. Scheele
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory Australia
| | - Marcel Cardillo
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
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12
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Turner GG, Sewall BJ, Scafini MR, Lilley TM, Bitz D, Johnson JS. Cooling of bat hibernacula to mitigate white-nose syndrome. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13803. [PMID: 34224186 DOI: 10.1111/cobi.13803] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/09/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
White-nose syndrome (WNS) is a fungal disease that has caused precipitous declines in several North American bat species, creating an urgent need for conservation. We examined how microclimates and other characteristics of hibernacula have affected bat populations following WNS-associated declines and evaluated whether cooling of warm, little-used hibernacula could benefit bats. During the period following mass mortality (2013-2020), we conducted 191 winter surveys of 25 unmanipulated hibernacula and 6 manipulated hibernacula across Pennsylvania (USA). We joined these data with additional datasets on historical (pre-WNS) bat counts and on the spatial distribution of underground sites. We used generalized linear mixed models and model selection to identify factors affecting bat populations. Winter counts of Myotis lucifugus were higher and increased over time in colder hibernacula (those with midwinter temperatures of 3-6 °C) compared with warmer (7-11 °C) hibernacula. Counts of Eptesicus fuscus, Myotis leibii, and Myotis septentrionalis were likewise higher in colder hibernacula (temperature effects = -0.73 [SE 0.15], -0.51 [0.18], and -0.97 [0.28], respectively). Populations of M. lucifugus and M. septentrionalis increased most over time in hibernacula surrounded by more nearby sites, whereas Eptesicus fuscus counts remained high where they had been high before WNS onset (pre-WNS high count effect = 0.59 [0.22]). Winter counts of M. leibii were higher in hibernacula with high vapor pressure deficits (VPDs) (particularly over 0.1 kPa) compared with sites with lower VPDs (VPD effect = 15.3 [4.6]). Counts of M. lucifugus and E. fuscus also appeared higher where VPD was higher. In contrast, Perimyotis subflavus counts increased over time in relatively warm hibernacula and were unaffected by VPD. Where we manipulated hibernacula, we achieved cooling of on average 2.1 °C. At manipulated hibernacula, counts of M. lucifugus and P. subflavus increased over time (years since manipulation effect = 0.70 [0.28] and 0.51 [0.15], respectively). Further, there were more E. fuscus where cooling was greatest (temperature difference effect = -0.46 [SE 0.11]), and there was some evidence there were more P. subflavus in hibernacula sections that remained warm after manipulation. These data show bats are responding effectively to WNS through habitat selection. In M. lucifugus, M. septentrionalis, and possibly P. subflavus, this response is ongoing, with bats increasingly aggregating at suitable hibernacula, whereas E. fuscus remain in previously favored sites. Our results suggest that cooling warm sites receiving little use by bats is a viable strategy for combating WNS.
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Affiliation(s)
| | - Brent J Sewall
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | | | - Thomas M Lilley
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Daniel Bitz
- CNX Gas Company LLC, Canonsburg, Pennsylvania, USA
| | - Joseph S Johnson
- Department of Biological Sciences, Ohio University, Athens, Ohio, USA
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13
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Kearney SG, Carwardine J, Reside AE, Adams VM, Nelson R, Coggan A, Spindler R, Watson JEM. Saving species beyond the protected area fence: Threats must be managed across multiple land tenure types to secure Australia's endangered species. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.617] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Stephen G. Kearney
- School of Earth and Environmental Sciences University of Queensland Brisbane Queensland Australia
| | | | - April E. Reside
- School of Biological Science University of Queensland Brisbane Queensland Australia
| | - Vanessa M. Adams
- School of Technology, Environments and Design University of Tasmania Hobart Tasmania Australia
| | - Rebecca Nelson
- University of Melbourne Law School Melbourne Victoria Australia
| | | | | | - James E. M. Watson
- School of Earth and Environmental Sciences University of Queensland Brisbane Queensland Australia
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14
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Genetic approaches for increasing fitness in endangered species. Trends Ecol Evol 2022; 37:332-345. [PMID: 35027225 DOI: 10.1016/j.tree.2021.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022]
Abstract
The global rate of wildlife extinctions is accelerating, and the persistence of many species requires conservation breeding programs. A central paradigm of these programs is to preserve the genetic diversity of the founder populations. However, this may preserve original characteristics that make them vulnerable to extinction. We introduce targeted genetic intervention (TGI) as an alternative approach that promotes traits that enable species to persist in the face of threats by changing the incidence of alleles that impact on fitness. The TGI toolkit includes methods with established efficacy in model organisms and agriculture but are largely untried for conservation, such as synthetic biology and artificial selection. We explore TGI approaches as a species-restoration tool for intractable threats including infectious disease and climate change.
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15
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Non-detection of mycoviruses in amphibian chytrid fungus (Batrachochytrium dendrobatidis) from Australia. Fungal Biol 2021; 126:75-81. [PMID: 34930560 DOI: 10.1016/j.funbio.2021.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 11/04/2022]
Abstract
Mycoviruses may influence the pathogenicity of disease-causing fungi. Although mycoviruses have been found in some chytrid fungi, limited testing has not detected them in Batrachochytrium dendrobatidis (Bd), the cause of the devastating amphibian disease, chytridiomycosis. Here we conducted a survey for mycovirus presence in 38 Bd isolates from Australia (n = 31), Brazil (n = 5) and South Korea (n = 2) with a combination of modern high-throughput sequencing and conventional dsRNA cellulose chromatography. Mycoviruses were not detected in any isolates. This result was unexpected, given the long evolutionary history of Bd, as well as the high prevalence of mycoviruses in related fungal species. Given our widespread sampling in Australia and the limited number of Bd introductions, we suggest that mycoviruses are uncommon or absent from Australian Bd. Testing more isolates from regions where Bd originated, as well as regions with high diversity or low fungal virulence may identify mycoviruses that could aid in disease control.
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16
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Scheele BC, Hollanders M, Hoffmann EP, Newell DA, Lindenmayer DB, McFadden M, Gilbert DJ, Grogan LF. Conservation translocations for amphibian species threatened by chytrid fungus: A review, conceptual framework, and recommendations. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.524] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ben C. Scheele
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Matthijs Hollanders
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - Emily P. Hoffmann
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
- School of Biological Sciences The University of Western Australia Crawley Western Australia Australia
| | - David A. Newell
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - David B. Lindenmayer
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Michael McFadden
- Taronga Conservation Society Australia Mosman New South Wales Australia
| | - Deon J. Gilbert
- Wildlife Conservation and Science Zoos Victoria Parkville Victoria Australia
| | - Laura F. Grogan
- Centre for Planetary Health and Food Security, School of Environment and Science Griffith University Southport Queensland Australia
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17
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Howell LG, Mawson PR, Frankham R, Rodger JC, Upton RMO, Witt RR, Calatayud NE, Clulow S, Clulow J. Integrating biobanking could produce significant cost benefits and minimise inbreeding for Australian amphibian captive breeding programs. Reprod Fertil Dev 2021; 33:573-587. [PMID: 38600658 DOI: 10.1071/rd21058] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/23/2021] [Indexed: 04/12/2024] Open
Abstract
Captive breeding is an important tool for amphibian conservation despite high economic costs and deleterious genetic effects of sustained captivity and unavoidably small colony sizes. Integration of biobanking and assisted reproductive technologies (ARTs) could provide solutions to these challenges, but is rarely used due to lack of recognition of the potential benefits and clear policy direction. Here we present compelling genetic and economic arguments to integrate biobanking and ARTs into captive breeding programs using modelled captive populations of two Australian threatened frogs, namely the orange-bellied frog Geocrinia vitellina and the white bellied frog Geocrinia alba . Back-crossing with frozen founder spermatozoa using ARTs every generation minimises rates of inbreeding and provides considerable reductions in colony size and program costs compared with conventional captive management. Biobanking could allow captive institutions to meet or exceed longstanding genetic retention targets (90% of source population heterozygosity over 100 years). We provide a broad policy direction that could make biobanking technology a practical reality across Australia's ex situ management of amphibians in current and future holdings. Incorporating biobanking technology widely across this network could deliver outcomes by maintaining high levels of source population genetic diversity and freeing economic resources to develop ex situ programs for a greater number of threatened amphibian species.
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Affiliation(s)
- Lachlan G Howell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and FAUNA Research Alliance, Kahibah, NSW 2290, Australia; and Corresponding author
| | - Peter R Mawson
- Perth Zoo, Department of Biodiversity, Conservation and Attractions, PO Box 489, South Perth, WA 6951, Australia
| | - Richard Frankham
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2019, Australia; and Australian Museum, Sydney, NSW 2010, Australia
| | - John C Rodger
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and FAUNA Research Alliance, Kahibah, NSW 2290, Australia
| | - Rose M O Upton
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and FAUNA Research Alliance, Kahibah, NSW 2290, Australia
| | - Ryan R Witt
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and FAUNA Research Alliance, Kahibah, NSW 2290, Australia
| | - Natalie E Calatayud
- San Diego Zoo Institute for Conservation Research, San Pasqual Valley Road, Escondido, CA 92027, USA; and Conservation Science Network, 24 Thomas Street, Mayfield, NSW 2304, Australia
| | - Simon Clulow
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and FAUNA Research Alliance, Kahibah, NSW 2290, Australia
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18
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Crawford-Ash J, Rowley JJL. Bad neighbours: amphibian chytrid fungus Batrachochytrium dendrobatidis infection dynamics in three co-occurring frog species of southern Sydney, Australia. DISEASES OF AQUATIC ORGANISMS 2021; 143:101-108. [PMID: 33570043 DOI: 10.3354/dao03557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Wildlife disease is a major cause of global biodiversity loss. Amongst the most devastating is the disease chytridiomycosis, caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). This disease has contributed to declines and extinctions in hundreds of amphibian species, but not all species are affected equally. Some amphibian hosts are capable of carrying high levels of Bd infection without population declines, acting as reservoir species for the pathogen and driving population declines in sympatric species. In Australia, several species have been proposed as reservoir species; however, our understanding of Bd is derived from studies that are highly geographically and taxonomically biased, and our ability to extrapolate from these systems is unknown. We examined the prevalence and intensity of Bd infection in 3 frog species in a previously unstudied host-pathogen system in temperate eastern Australia: the Blue Mountains tree frog Litoria citropa, a poorly-known species predicted to be susceptible to Bd infection; and the common eastern froglet Crinia signifera and the stony creek frog L. lesueuri, which have both been identified as reservoir species in other regions. We found that L. citropa and L. lesueuri were infected with Bd at a high prevalence and often high intensity, while the reverse was true for C. signifera. All species were detected at moderate abundance and there was no evidence of morbidity and mortality. Our findings do not support C. signifera and L. lesueuri being reservoir species in this system, highlighting the importance of region-specific studies to inform conservation management.
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Affiliation(s)
- Jordann Crawford-Ash
- Australian Museum Research Institute, Australian Museum, 1 William St, Sydney, NSW 2010, Australia
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19
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McCarthy JK, Wiser SK, Bellingham PJ, Beresford RM, Campbell RE, Turner R, Richardson SJ. Using spatial models to identify refugia and guide restoration in response to an invasive plant pathogen. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.13756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
| | | | - Peter J. Bellingham
- Manaaki Whenua – Landcare Research Lincoln New Zealand
- School of Biological Sciences University of Auckland Auckland New Zealand
| | - Robert M. Beresford
- The New Zealand Institute for Plant and Food Research Ltd Auckland New Zealand
| | - Rebecca E. Campbell
- The New Zealand Institute for Plant and Food Research Ltd Motueka New Zealand
| | - Richard Turner
- National Institute of Water and Atmospheric Research Ltd Wellington New Zealand
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20
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Burns TJ, Scheele BC, Brannelly LA, Clemann N, Gilbert D, Driscoll DA. Indirect terrestrial transmission of amphibian chytrid fungus from reservoir to susceptible host species leads to fatal chytridiomycosis. Anim Conserv 2020. [DOI: 10.1111/acv.12665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas J. Burns
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University (Burwood Campus) Geelong Vic. Australia
| | - Ben C. Scheele
- Fenner School of Environment and Society Australian National University Canberra ACT Australia
| | - Laura A. Brannelly
- Melbourne Veterinary School Faculty of Veterinary and Agricultural Sciences University of Melbourne Werribee Vic. Australia
| | - Nick Clemann
- Department of Environment, Land, Water and Planning Arthur Rylah Institute for Environmental Research Heidelberg Vic. Australia
| | - Deon Gilbert
- Wildlife Conservation and Science. Zoos Victoria Parkville Vic. Australia
| | - Don A. Driscoll
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University (Burwood Campus) Geelong Vic. Australia
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21
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Bosch J, Carrascal LM, Manica A, Garner TWJ. Significant reductions of host abundance weakly impact infection intensity of Batrachochytrium dendrobatidis. PLoS One 2020; 15:e0242913. [PMID: 33253322 PMCID: PMC7703926 DOI: 10.1371/journal.pone.0242913] [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: 03/17/2020] [Accepted: 11/10/2020] [Indexed: 11/19/2022] Open
Abstract
Infectious diseases are considered major threats to biodiversity, however strategies to mitigate their impacts in the natural world are scarce and largely unsuccessful. Chytridiomycosis is responsible for the decline of hundreds of amphibian species worldwide, but an effective disease management strategy that could be applied across natural habitats is still lacking. In general amphibian larvae can be easily captured, offering opportunities to ascertain the impact of altering the abundance of hosts, considered to be a key parameter affecting the severity of the disease. Here, we report the results of two experiments to investigate how altering host abundance affects infection intensity in amphibian populations of a montane area of Central Spain suffering from lethal amphibian chytridiomycosis. Our laboratory-based experiment supported the conclusion that varying density had a significant effect on infection intensity when salamander larvae were housed at low densities. Our field experiment showed that reducing the abundance of salamander larvae in the field also had a significant, but weak, impact on infection the following year, but only when removals were extreme. While this suggests adjusting host abundance as a mitigation strategy to reduce infection intensity could be useful, our evidence suggests only heavy culling efforts will succeed, which may run contrary to objectives for conservation.
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Affiliation(s)
- Jaime Bosch
- Research Unit of Biodiversity (CSIC, UO, PA), Gonzalo Gutiérrez Quirós s/n, Oviedo University - Campus Mieres, Edificio de Investigación, Mieres, Spain
- Centro de Investigación, Seguimiento y Evaluación, Rascafría, Spain
- Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
| | | | - Andrea Manica
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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22
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Sieber N, Hartikainen H, Vorburger C. Validation of an eDNA-based method for the detection of wildlife pathogens in water. DISEASES OF AQUATIC ORGANISMS 2020; 141:171-184. [PMID: 33089822 DOI: 10.3354/dao03524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Monitoring the occurrence and density of parasites and pathogens can identify high infection-risk areas and facilitates disease control and eradication measures. Environmental DNA (eDNA) techniques are increasingly used for pathogen detection due to their relative ease of application. Since many factors affect the reliability and efficacy of eDNA-based detection, rigorous validation and assessment of method limitations is a crucial first step. We evaluated an eDNA detection method using in situ filtration of large-volume water samples, developed to detect and quantify aquatic wildlife parasites by quantitative PCR (qPCR). We assessed method reliability using Batrachochytrium dendrobatidis, a pathogenic fungus of amphibians and the myxozoan Tetracapsuloides bryosalmonae, causative agent of salmonid proliferative kidney disease, in a controlled experimental setup. Different amounts of parasite spores were added to tanks containing either clean tap water or water from a semi-natural mesocosm community. Overall detection rates were higher than 80%, but detection was not consistent among replicate samples. Within-tank variation in detection emphasises the need for increased site-level replication when dealing with parasites and pathogens. Estimated parasite DNA concentrations in water samples were highly variable, and a significant increase with higher spore concentrations was observed only for B. dendrobatidis. Despite evidence for PCR inhibition in DNA extractions from mesocosm water samples, the type of water did not affect detection rates significantly. Direct spiking controls revealed that the filtration step reduced detection sensitivity. Our study identifies sensitive quantification and sufficient replication as major remaining challenges for the eDNA-based methods for detection of parasites in water.
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Affiliation(s)
- Natalie Sieber
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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23
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Brannelly LA, McCallum HI, Grogan LF, Briggs CJ, Ribas MP, Hollanders M, Sasso T, Familiar López M, Newell DA, Kilpatrick AM. Mechanisms underlying host persistence following amphibian disease emergence determine appropriate management strategies. Ecol Lett 2020; 24:130-148. [PMID: 33067922 DOI: 10.1111/ele.13621] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/18/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022]
Abstract
Emerging infectious diseases have caused many species declines, changes in communities and even extinctions. There are also many species that persist following devastating declines due to disease. The broad mechanisms that enable host persistence following declines include evolution of resistance or tolerance, changes in immunity and behaviour, compensatory recruitment, pathogen attenuation, environmental refugia, density-dependent transmission and changes in community composition. Here we examine the case of chytridiomycosis, the most important wildlife disease of the past century. We review the full breadth of mechanisms allowing host persistence, and synthesise research on host, pathogen, environmental and community factors driving persistence following chytridiomycosis-related declines and overview the current evidence and the information required to support each mechanism. We found that for most species the mechanisms facilitating persistence have not been identified. We illustrate how the mechanisms that drive long-term host population dynamics determine the most effective conservation management strategies. Therefore, understanding mechanisms of host persistence is important because many species continue to be threatened by disease, some of which will require intervention. The conceptual framework we describe is broadly applicable to other novel disease systems.
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Affiliation(s)
- Laura A Brannelly
- Veterinary BioSciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Vic, 3030, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia.,Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Maria P Ribas
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia.,Wildlife Conservation Medicine Research Group, Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Matthijs Hollanders
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Thais Sasso
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Mariel Familiar López
- School of Environment and Sciences, Griffith University, Gold Coast, Qld., 4215, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Auston M Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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24
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Bell SC, Heard GW, Berger L, Skerratt LF. Connectivity over a disease risk gradient enables recovery of rainforest frogs. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02152. [PMID: 32343856 DOI: 10.1002/eap.2152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/14/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
Chytridiomycosis has been a key driver of global frog declines and extinctions, particularly for high-altitude populations across Australia and the Americas. While recent evidence shows some species are recovering, the extent of such recoveries and the mechanisms underpinning them remain poorly resolved. We surveyed the historical latitudinal and elevational range of four Australian rainforest frogs that disappeared from upland sites between 1989 and 1994 to establish their contemporary distribution and elevational limits, and investigate factors affecting population recovery. Five rainforest streams were surveyed from mountain-base to summit (30 sites in total), with swabs collected from the target species (Litoria dayi, L. nannotis, L. rheocola, and L. serrata) to determine their infection status, and data loggers deployed to measure microclimatic variation across the elevational gradient. Infection probability increased with elevation and canopy cover as it was tightly and inversely correlated with stream-side air temperature. Occupancy patterns suggest varying responses to this disease threat gradient. Two species, L. rheocola and L. serrata, were found over their full historical elevational range (≥1,000 m above sea level [asl]), while L. dayi was not detected above 400 m (formerly known up to 900 m asl) and L. nannotis was not detected above 800 m (formerly known up to 1,200 m asl). Site occupancy probability was negatively related to predicted infection prevalence for L. dayi, L. nannotis, and L. rheocola, but not L. serrata, which appears to now tolerate high fungal burdens. This study highlights the importance of environmental refuges and connectivity across disease risk gradients for the persistence and natural recovery of frogs susceptible to chytridiomycosis. Likewise, in documenting both interspecific variation in recovery rates and intraspecific differences between sites, this study suggests interactions between disease threats and host selection exist that could be manipulated. For example, translocations may be warranted where connectivity is poor or the increase in disease risk is too steep to allow recolonization, combined with assisted selection or use of founders from populations that have already undergone natural selection.
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Affiliation(s)
- Sara C Bell
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Geoffrey W Heard
- Institute of Land, Water and Society, Charles Sturt University, Albury, New South Wales, 2640, Australia
- Victorian Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, 3084, Australia
| | - Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
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25
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Bower DS, Jennings CK, Webb RJ, Amepou Y, Schwarzkopf L, Berger L, Alford RA, Georges A, McKnight DT, Carr L, Nason D, Clulow S. Disease surveillance of the amphibian chytrid fungus
Batrachochytrium dendrobatidis
in Papua New Guinea. CONSERVATION SCIENCE AND PRACTICE 2020. [DOI: 10.1111/csp2.256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Deborah S. Bower
- College of Science & EngineeringJames Cook University Townsville Queensland Australia
- School of Earth and Environmental ScienceUniversity of New England Armidale New South Wales Australia
| | | | - Rebecca J. Webb
- College of Public HealthMedical and Veterinary Sciences, James Cook University
| | - Yolarnie Amepou
- Institute for Applied EcologyUniversity of Canberra Canberra Australian Capital Territory Australia
| | - Lin Schwarzkopf
- College of Science & EngineeringJames Cook University Townsville Queensland Australia
| | - Lee Berger
- Melbourne Veterinary SchoolUniversity of Melbourne Werribee Victoria Australia
| | - Ross A. Alford
- College of Science & EngineeringJames Cook University Townsville Queensland Australia
| | - Arthur Georges
- Institute for Applied EcologyUniversity of Canberra Canberra Australian Capital Territory Australia
| | - Donald T. McKnight
- College of Science & EngineeringJames Cook University Townsville Queensland Australia
- School of Earth and Environmental ScienceUniversity of New England Armidale New South Wales Australia
| | - Leah Carr
- College of Science & EngineeringJames Cook University Townsville Queensland Australia
| | - Dillian Nason
- Biological Science DepartmentUniversity of Goroka Goroka Papua New Guinea
| | - Simon Clulow
- School of Environmental and Life ScienceUniversity of Newcastle Callaghan New South Wales Australia
- Department of Biological SciencesMacquarie University Sydney New South Wales Australia
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26
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Peters A, Carver S, Skerratt LF, Meredith A, Woods R. A Solutions-Focused Translational Research Framework for Wildlife Health. Bioscience 2019. [DOI: 10.1093/biosci/biz125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Abstract
Wildlife health is of emerging relevance for conservation, human health, and domestic animal health. Increased research on wildlife health problems has not been accompanied by a relative increase in effective solutions. Translational research was developed in human health to overcome blocks impeding the development of solutions out of basic research, and a translational research framework is proposed to overcome the same barriers in wildlife health. This framework has four translational phases: problem definition, potential solution development, efficacious solution development, and effective solution development. Implementation of translational research will require a restructuring of the wildlife health research enterprise with a shift, supported by funding sources and journals, to solutions-focused research including later translational phases, the creation of more deeply integrated multidisciplinary and interdisciplinary teams incorporating better representation from human social sciences, and the inclusion of end user and stakeholder participation in all phases of research.
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Affiliation(s)
- Andrew Peters
- Institute of Land, Water and Society and the School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, Australia
| | - Scott Carver
- Department of Biological Sciences, University of Tasmania, Hobart, Australia
| | - Lee F Skerratt
- Health Research Group, University of Melbourne, Melbourne, Australia
| | - Anna Meredith
- Melbourne Veterinary School, University of Melbourne, Melbourne, Australia
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27
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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: 87] [Impact Index Per Article: 14.5] [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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28
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Brannelly LA, Martin G, Llewelyn J, Skerratt LF, Berger L. Age- and size-dependent resistance to chytridiomycosis in the invasive cane toad Rhinella marina. DISEASES OF AQUATIC ORGANISMS 2018; 131:107-120. [PMID: 30460917 DOI: 10.3354/dao03278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In Australia, the cane toad Rhinella marina and chytrid fungus Batrachochytrium dendrobatidis (Bd) are examples of invasive species that have had dramatic impacts on native fauna. However, little is known about the interaction between Bd and cane toads. We aimed to explore the interaction of these 2 species in 3 parts. First, we collated data from the literature on Bd infection in wild cane toads. Second, we tested the susceptibility of recently metamorphosed cane toads to Bd infection. Finally, we modelled the distribution of the 2 species in Australia to identify where they overlap and, therefore, might interact. Through our data collation, we found that adult cane toads are infrequently infected and do not carry high infection burdens; however, our infection experiment showed that metamorphs are highly susceptible to infection and disease, but resistance appears to increase with increasing toad size. Niche modelling revealed overlapping distributions and the potential for cane toads to be affected by chytridiomycosis in the wild. While Bd can cause mortality in small juveniles in the laboratory, warm microhabitats used by wild toads likely prevent infection, and furthermore, high mortality of juveniles is unlikely to affect the adult populations because they are highly fecund. However, to demonstrate the impact of Bd on wild cane toad populations, targeted field studies are required to assess (1) the overall impact of chytridiomycosis on recruitment especially in cooler areas more favourable for Bd and (2) whether cane toad juveniles can amplify Bd exposure of native amphibian species in these areas.
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Affiliation(s)
- Laura A Brannelly
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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29
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Michael DR, Blanchard W, Scheele BC, Lindenmayer DB. Comparative use of active searches and artificial refuges to detect amphibians in terrestrial environments. AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Damian R. Michael
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory 2601 Australia
- National Environmental Science Program Threatened Species Recovery Hub The Australian National University Canberra Australian Capital Territory Australia
- Sustainable Farms Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory Australia
| | - Wade Blanchard
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory 2601 Australia
| | - Ben C. Scheele
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory 2601 Australia
- National Environmental Science Program Threatened Species Recovery Hub The Australian National University Canberra Australian Capital Territory Australia
| | - David B. Lindenmayer
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory 2601 Australia
- National Environmental Science Program Threatened Species Recovery Hub The Australian National University Canberra Australian Capital Territory Australia
- Sustainable Farms Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory Australia
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30
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Clulow J, Pomering M, Herbert D, Upton R, Calatayud N, Clulow S, Mahony MJ, Trudeau VL. Differential success in obtaining gametes between male and female Australian temperate frogs by hormonal induction: A review. Gen Comp Endocrinol 2018; 265:141-148. [PMID: 29859744 DOI: 10.1016/j.ygcen.2018.05.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/13/2018] [Accepted: 05/30/2018] [Indexed: 01/19/2023]
Abstract
Most Australian frogs fall into two deeply split lineages, conveniently referred to as ground frogs (Myobatrachidae and Limnodynastidae) and tree frogs (Pelodryadidae). Species of both lineages are endangered because of the global chytrid pandemic, and there is increasing interest and research on the endocrine manipulation of reproduction to support the use of assisted reproductive technologies in conservation. Hormonal induction of gamete release in males and females is one such manipulation of the reproductive process. This paper reviews progress in temperate ground and tree frogs towards developing simple and efficient hormonal protocols for induction of spermiation and ovulation, and presents some new data, that together build towards an understanding of advances and obstacles towards progress in this area. We report that protocols for the non-invasive induction of sperm release, relying on single doses of gonadotropin-releasing hormone (GnRH) or human chorionic gonadotropin are very effective in both ground and tree frog species investigated to date. However, we find that, while protocols based on GnRH, and GnRH and dopamine antagonists, are moderately efficient in inducing ovulation in ground frogs, the same cannot be said for the use of such protocols in tree frogs. Although induced ovulation in the pelodryadid tree frogs has not been successfully implemented, and is difficult to explain in terms of the underlying endocrinology, we propose future avenues of investigation to address this problem, particularly the need for a source of purified or recombinant follicle-stimulating hormone and luteinising hormone for species from this group.
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Affiliation(s)
- John Clulow
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia.
| | - Melissa Pomering
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia
| | - Danielle Herbert
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia
| | - Rose Upton
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia
| | - Natalie Calatayud
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | - Simon Clulow
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia; Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109 Australia
| | - Michael J Mahony
- Conservation Biology Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308 Australia
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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31
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Spitzen-van der Sluijs A, Canessa S, Martel A, Pasmans F. Fragile coexistence of a global chytrid pathogen with amphibian populations is mediated by environment and demography. Proc Biol Sci 2018; 284:rspb.2017.1444. [PMID: 28978729 DOI: 10.1098/rspb.2017.1444] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/30/2017] [Indexed: 01/05/2023] Open
Abstract
Unravelling the multiple interacting drivers of host-pathogen coexistence is crucial in understanding how an apparently stable state of endemism may shift towards an epidemic and lead to biodiversity loss. Here, we investigate the apparent coexistence of the global amphibian pathogen Batrachochytrium dendrobatidis (Bd) with Bombina variegata populations in The Netherlands over a 7-year period. We used a multi-season mark-recapture dataset and assessed potential drivers of coexistence (individual condition, environmental mediation and demographic compensation) at the individual and population levels. We show that even in a situation with a clear cost incurred by endemic Bd, population sizes remain largely stable. Current environmental conditions and an over-dispersed pathogen load probably stabilize disease dynamics, but as higher temperatures increase infection probability, changing environmental conditions, for example a climate-change-driven rise in temperature, could unbalance the current fragile host-pathogen equilibrium. Understanding the proximate mechanisms of such environmental mediation and of site-specific differences in infection dynamics can provide vital information for mitigation actions.
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Affiliation(s)
- Annemarieke Spitzen-van der Sluijs
- Reptile, Amphibian and Fish Conservation Netherlands, PO Box 1413, 6501 BK Nijmegen, The Netherlands .,Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Stefano Canessa
- 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
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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32
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Affiliation(s)
- Thomas R. Raffel
- Department of Biological Sciences Oakland University Rochester MI USA
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33
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Survival, gene and metabolite responses of Litoria verreauxii alpina frogs to fungal disease chytridiomycosis. Sci Data 2018; 5:180033. [PMID: 29509187 PMCID: PMC5839156 DOI: 10.1038/sdata.2018.33] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022] Open
Abstract
The fungal skin disease chytridiomycosis has caused the devastating decline and extinction of hundreds of amphibian species globally, yet the potential for evolving resistance, and the underlying pathophysiological mechanisms remain poorly understood. We exposed 406 naïve, captive-raised alpine tree frogs (Litoria verreauxii alpina) from multiple populations (one evolutionarily naïve to chytridiomycosis) to the aetiological agent Batrachochytrium dendrobatidis in two concurrent and controlled infection experiments. We investigated (A) survival outcomes and clinical pathogen burdens between populations and clutches, and (B) individual host tissue responses to chytridiomycosis. Here we present multiple interrelated datasets associated with these exposure experiments, including animal signalment, survival and pathogen burden of 355 animals from Experiment A, and the following datasets related to 61 animals from Experiment B: animal signalment and pathogen burden; raw RNA-Seq reads from skin, liver and spleen tissues; de novo assembled transcriptomes for each tissue type; raw gene expression data; annotation data for each gene; and raw metabolite expression data from skin and liver tissues. These data provide an extensive baseline for future analyses.
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34
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Grogan LF, Cashins SD, Skerratt LF, Berger L, McFadden MS, Harlow P, Hunter DA, Scheele BC, Mulvenna J. Evolution of resistance to chytridiomycosis is associated with a robust early immune response. Mol Ecol 2018; 27:919-934. [DOI: 10.1111/mec.14493] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/30/2017] [Accepted: 09/18/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Laura F. Grogan
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
- Griffith Wildlife Disease Ecology Group Environmental Futures Research Institute School of Environment Griffith University Nathan QLD Australia
- Genetics and Computational Biology QIMR Berghofer Medical Research Institute Brisbane QLD Australia
| | - Scott D. Cashins
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | - Lee F. Skerratt
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | - Lee Berger
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | | | - Peter Harlow
- Taronga Conservation Society Australia Mosman NSW Australia
| | - David A. Hunter
- Ecosystems and Threatened Species South West Region Office of Environment and Heritage NSW Department of Premier and Cabinet Queanbeyan NSW Australia
| | - Ben C. Scheele
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
- Fenner School of Environment and Society Australian National University Canberra ACT Australia
| | - Jason Mulvenna
- Genetics and Computational Biology QIMR Berghofer Medical Research Institute Brisbane QLD Australia
- School of Biomedical Sciences The University of Queensland Brisbane QLD Australia
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35
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Hoskin CJ, Hines HB, Webb RJ, Skerratt LF, Berger L. Naïve rainforest frogs on Cape York, Australia, are at risk of the introduction of amphibian chytridiomycosis disease. AUST J ZOOL 2018. [DOI: 10.1071/zo18041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Amphibian chytridiomycosis disease has caused widespread declines and extinctions of frogs in cool, wet habitats in eastern Australia. Screening suggests that the disease does not yet occupy all areas modelled to be environmentally suitable, including rainforests on Cape York Peninsula. Cape Melville is an area of rainforest with several endemic frogs, including the stream-associated Melville Range treefrog (Litoria andiirrmalin), which is deemed at particular risk of disease impacts. We tested 40 L. andiirrmalin for chytrid infection by PCR and found them all to be negative. In conjunction with previous testing at another high-risk location, McIlwraith Range, this suggests that endemic rainforest frogs on Cape York have been spared the introduction of chytridiomycosis. We discuss how the disease could get to these areas, what can be done to reduce the risk, and suggest an emergency procedure should it be introduced.
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36
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Lips KR. Overview of chytrid emergence and impacts on amphibians. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0465. [PMID: 28080989 DOI: 10.1098/rstb.2015.0465] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2016] [Indexed: 11/12/2022] Open
Abstract
Chytridiomycosis is an emerging infectious disease of amphibians that affects over 700 species on all continents where amphibians occur. The amphibian-chytridiomycosis system is complex, and the response of any amphibian species to chytrid depends on many aspects of the ecology and evolutionary history of the amphibian, the genotype and phenotype of the fungus, and how the biological and physical environment can mediate that interaction. Impacts of chytridiomycosis on amphibians are varied; some species have been driven extinct, populations of others have declined severely, whereas still others have not obviously declined. Understanding patterns and mechanisms of amphibian responses to chytrids is critical for conservation and management. Robust estimates of population numbers are needed to identify species at risk, prioritize taxa for conservation actions, design management strategies for managing populations and species, and to develop effective measures to reduce impacts of chytrids on amphibians.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Karen R Lips
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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37
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Garner TWJ, Schmidt BR, Martel A, Pasmans F, Muths E, Cunningham AA, Weldon C, Fisher MC, Bosch J. Mitigating amphibian chytridiomycoses in nature. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0207. [PMID: 28080996 DOI: 10.1098/rstb.2016.0207] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Trenton W J Garner
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK .,Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Benedikt R Schmidt
- Karch, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Fort Collins, 2150 Centre Avenue Building C, Fort Collins, CO 80526, USA
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK
| | - Che Weldon
- Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain
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38
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Brannelly LA, Webb RJ, Hunter DA, Clemann N, Howard K, Skerratt LF, Berger L, Scheele BC. Non-declining amphibians can be important reservoir hosts for amphibian chytrid fungus. Anim Conserv 2017. [DOI: 10.1111/acv.12380] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- L. A. Brannelly
- One Health Research Group; James Cook University; Townsville QLD Australia
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh PA USA
| | - R. J. Webb
- One Health Research Group; James Cook University; Townsville QLD Australia
| | - D. A. Hunter
- New South Wales Office of Environment and Heritage; Albury NSW Australia
| | - N. Clemann
- Department of Environment, Land Water and Planning; Arthur Rylah Institute for Environmental Research; Heidelberg VIC Australia
| | - K. Howard
- Department of Environment, Land Water and Planning; Arthur Rylah Institute for Environmental Research; Heidelberg VIC Australia
| | - L. F. Skerratt
- One Health Research Group; James Cook University; Townsville QLD Australia
| | - L. Berger
- One Health Research Group; James Cook University; Townsville QLD Australia
| | - B. C. Scheele
- One Health Research Group; James Cook University; Townsville QLD Australia
- Fenner School of Environment and Society; Australian National University; Canberra ACT Australia
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39
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40
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Antifungal treatment of wild amphibian populations caused a transient reduction in the prevalence of the fungal pathogen, Batrachochytrium dendrobatidis. Sci Rep 2017; 7:5956. [PMID: 28729557 PMCID: PMC5519715 DOI: 10.1038/s41598-017-05798-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/06/2017] [Indexed: 01/09/2023] Open
Abstract
Emerging infectious diseases can drive host populations to extinction and are a major driver of biodiversity loss. Controlling diseases and mitigating their impacts is therefore a priority for conservation science and practice. Chytridiomycosis is a devastating disease of amphibians that is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), and for which there is an urgent need to develop mitigation methods. We treated tadpoles of the common midwife toad (Alytes obstetricans) with antifungal agents using a capture-treat-release approach in the field. Antifungal treatment during the spring reduced the prevalence of Bd in the cohort of tadpoles that had overwintered and reduced transmission of Bd from this cohort to the uninfected young-of-the-year cohort. Unfortunately, the mitigation was only transient, and the antifungal treatment was unable to prevent the rapid spread of Bd through the young-of-the year cohort. During the winter, Bd prevalence reached 100% in both the control and treated ponds. In the following spring, no effects of treatment were detectable anymore. We conclude that the sporadic application of antifungal agents in the present study was not sufficient for the long-term and large-scale control of Bd in this amphibian system.
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41
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Scheele BC, Skerratt LF, Hunter DA, Banks SC, Pierson JC, Driscoll DA, Byrne PG, Berger L. Disease-associated change in an amphibian life-history trait. Oecologia 2017; 184:825-833. [DOI: 10.1007/s00442-017-3911-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 07/06/2017] [Indexed: 11/30/2022]
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42
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Scheele BC, Hunter DA, Brannelly LA, Skerratt LF, Driscoll DA. Reservoir-host amplification of disease impact in an endangered amphibian. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:592-600. [PMID: 27594575 DOI: 10.1111/cobi.12830] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 04/20/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts-species that carry infection while maintaining high abundance but are rarely killed by disease-can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined amphibian species.
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Affiliation(s)
- Ben C Scheele
- Fenner School of Environment and Society, Australian National University, Canberra, ACT, 2601, Australia
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - David A Hunter
- New South Wales Office of Environment and Heritage, Albury, NSW, 2640, Australia
| | - Laura A Brannelly
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Don A Driscoll
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Australia
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43
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Heard GW, Scroggie MP, Ramsey DSL, Clemann N, Hodgson JA, Thomas CD. Can Habitat Management Mitigate Disease Impacts on Threatened Amphibians? Conserv Lett 2017. [DOI: 10.1111/conl.12375] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Geoffrey W. Heard
- School of BioSciences; University of Melbourne; Parkville VIC 3010 Australia
| | - Michael P. Scroggie
- Department of Environment, Land, Water and Planning; Arthur Rylah Institute for Environmental Research; P.O. Box 137 Heidelberg VIC 3084 Australia
| | - David S. L. Ramsey
- Department of Environment, Land, Water and Planning; Arthur Rylah Institute for Environmental Research; P.O. Box 137 Heidelberg VIC 3084 Australia
| | - Nick Clemann
- Department of Environment, Land, Water and Planning; Arthur Rylah Institute for Environmental Research; P.O. Box 137 Heidelberg VIC 3084 Australia
| | - Jenny A. Hodgson
- Department of Evolution, Ecology and Behaviour; University of Liverpool; Liverpool L69 7ZB UK
| | - Chris D. Thomas
- Department of Biology; University of York; Heslington York YO10 5DD UK
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44
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Whilde J, Martindale MQ, Duffy DJ. Precision wildlife medicine: applications of the human-centred precision medicine revolution to species conservation. GLOBAL CHANGE BIOLOGY 2017; 23:1792-1805. [PMID: 27809394 DOI: 10.1111/gcb.13548] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/21/2016] [Indexed: 06/06/2023]
Abstract
The current species extinction crisis is being exacerbated by an increased rate of emergence of epizootic disease. Human-induced factors including habitat degradation, loss of biodiversity and wildlife population reductions resulting in reduced genetic variation are accelerating disease emergence. Novel, efficient and effective approaches are required to combat these epizootic events. Here, we present the case for the application of human precision medicine approaches to wildlife medicine in order to enhance species conservation efforts. We consider how the precision medicine revolution, coupled with the advances made in genomics, may provide a powerful and feasible approach to identifying and treating wildlife diseases in a targeted, effective and streamlined manner. A number of case studies of threatened species are presented which demonstrate the applicability of precision medicine to wildlife conservation, including sea turtles, amphibians and Tasmanian devils. These examples show how species conservation could be improved by using precision medicine techniques to determine novel treatments and management strategies for the specific medical conditions hampering efforts to restore population levels. Additionally, a precision medicine approach to wildlife health has in turn the potential to provide deeper insights into human health and the possibility of stemming and alleviating the impacts of zoonotic diseases. The integration of the currently emerging Precision Medicine Initiative with the concepts of EcoHealth (aiming for sustainable health of people, animals and ecosystems through transdisciplinary action research) and One Health (recognizing the intimate connection of humans, animal and ecosystem health and addressing a wide range of risks at the animal-human-ecosystem interface through a coordinated, collaborative, interdisciplinary approach) has great potential to deliver a deeper and broader interdisciplinary-based understanding of both wildlife and human diseases.
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Affiliation(s)
- Jenny Whilde
- The Whitney Laboratory for Marine Bioscience & Sea Turtle Hospital, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, FL, 32080-8610, USA
| | - Mark Q Martindale
- The Whitney Laboratory for Marine Bioscience & Sea Turtle Hospital, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, FL, 32080-8610, USA
| | - David J Duffy
- The Whitney Laboratory for Marine Bioscience & Sea Turtle Hospital, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, FL, 32080-8610, USA
- Systems Biology Ireland, Science Link Building, University College Dublin, Belfield, Dublin 4, Ireland
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45
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Brannelly LA, Roberts AA, Skerratt LF, Berger L. Epidermal cell death in frogs with chytridiomycosis. PeerJ 2017; 5:e2925. [PMID: 28168107 PMCID: PMC5291105 DOI: 10.7717/peerj.2925] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/19/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Amphibians are declining at an alarming rate, and one of the major causes of decline is the infectious disease chytridiomycosis. Parasitic fungal sporangia occur within epidermal cells causing epidermal disruption, but these changes have not been well characterised. Apoptosis (planned cell death) can be a damaging response to the host but may alternatively be a mechanism of pathogen removal for some intracellular infections. METHODS In this study we experimentally infected two endangered amphibian species Pseudophryne corroboree and Litoria verreauxii alpina with the causal agent of chytridiomycosis. We quantified cell death in the epidermis through two assays: terminal transferase-mediated dUTP nick end-labelling (TUNEL) and caspase 3/7. RESULTS Cell death was positively associated with infection load and morbidity of clinically infected animals. In infected amphibians, TUNEL positive cells were concentrated in epidermal layers, correlating to the localisation of infection within the skin. Caspase activity was stable and low in early infection, where pathogen loads were light but increasing. In animals that recovered from infection, caspase activity gradually returned to normal as the infection cleared. Whereas, in amphibians that did not recover, caspase activity increased dramatically when infection loads peaked. DISCUSSION Increased cell death may be a pathology of the fungal parasite, likely contributing to loss of skin homeostatic functions, but it is also possible that apoptosis suppression may be used initially by the pathogen to help establish infection. Further research should explore the specific mechanisms of cell death and more specifically apoptosis regulation during fungal infection.
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Affiliation(s)
- Laura A Brannelly
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University , Townsville , QLD , Australia
| | - Alexandra A Roberts
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University , Townsville , QLD , 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, University of Melbourne, Melbourne, Victoria, Australia
| | - 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, University of Melbourne, Melbourne, Victoria, Australia
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46
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Goldingay RL, Parkyn J, Newell DA. No evidence of protracted population decline across 17 years in an unmanaged population of the green and golden bell frog in north-eastern New South Wales. AUST J ZOOL 2017. [DOI: 10.1071/zo16087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Describing the population trends of threatened species over time is central to their management and conservation. The green and golden bell frog (Litoria aurea) is a formerly common species of south-eastern Australia that has declined to ~40 populations in New South Wales, and experienced a substantial contraction of its geographic range. We aimed to determine whether an unmanaged population at the northern end of its range had declined across a 17-year period. We estimated population size at the beginning and end of this period, using several population models to fully characterise this population. Different modelling approaches gave different population estimates. Based on a similar number of survey occasions the adult male segment of the population was estimated using the Popan model at 112.0 (±13.5, s.e.; 95% CI: 85.5–138.8) in 1998/99 and 95.2 (±17.6; 60.8–129.7) in 2015/16. With the inclusion of maturing subadults following the practice of earlier studies, the population was estimated at 163.6 (±25.9; 112.8–214.5) males in 2015/16. These estimates represent an index of a larger population because the largest wetland was subsampled. Our data provide no evidence of a declining population. Our study highlights the need to understand the implications of using different population models and two age-classes to estimate population parameters.
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García‐Díaz P, Ross JV, Woolnough AP, Cassey P. Managing the risk of wildlife disease introduction: pathway‐level biosecurity for preventing the introduction of alien ranaviruses. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Pablo García‐Díaz
- School of Biological Sciences and Centre for Conservation Science and Technology (CCoST) The University of Adelaide North Terrace SA 5005 Australia
| | - Joshua V. Ross
- School of Mathematical Sciences NHMRC Centre of Research Excellence in Policy Relevant Infectious Diseases Simulation and Mathematical Modelling (PRISM2) Centre for Conservation Science and Technology (CCoST), and ARC Centre of Excellence for Mathematical and Statistical Frontiers (ACEMS) The University of Adelaide North Terrace SA 5005 Australia
| | - Andrew P. Woolnough
- Department of Economic Development, Jobs, Transport and Resources 475‐485 Mickleham Road Attwood Vic. 3049 Australia
| | - Phillip Cassey
- School of Biological Sciences and Centre for Conservation Science and Technology (CCoST) The University of Adelaide North Terrace SA 5005 Australia
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