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Logan SR, Vilaça ST, Bienentreu JF, Schock DM, Lesbarrères D, Brunetti CR. Isolation and Characterization of a Frog Virus 3 Strain from a Wood Frog ( Rana sylvatica) in Wood Buffalo National Park. Viruses 2024; 16:1411. [PMID: 39339887 PMCID: PMC11436234 DOI: 10.3390/v16091411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2024] [Revised: 08/27/2024] [Accepted: 08/28/2024] [Indexed: 09/30/2024] Open
Abstract
Members of the Iridoviridae family, genus Ranavirus, represent a group of globally emerging pathogens of ecological and economic importance. In 2017, an amphibian die-off of wood frogs (Rana sylvatica) and boreal chorus frogs (Pseudacris maculata) was reported in Wood Buffalo National Park, Canada. Isolation and complete genomic sequencing of the tissues of a wood frog revealed the presence of a frog virus 3 (FV3)-like isolate, Rana sylvatica ranavirus (RSR), with a genome size of 105,895 base pairs, 97 predicted open reading frames (ORFs) bearing sequence similarity to FV3 (99.98%) and a FV3-like isolate from a spotted salamander in Maine (SSME; 99.64%). Despite high sequence similarity, RSR had a unique genomic composition containing ORFs specific to either FV3 or SSME. In addition, RSR had a unique 13 amino acid insertion in ORF 49/50L. No differences were found in the in vitro growth kinetics of FV3, SSME, and RSR; however, genomic differences between these isolates were in non-core genes, implicated in nucleic acid metabolism and immune evasion. This study highlights the importance of viral isolation and complete genomic analysis as these not only provide information on ranavirus spatial distribution but may elucidate genomic factors contributing to host tropism and pathogenicity.
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Affiliation(s)
- Samantha R Logan
- Department of Biology, Trent University, 1600 West Bank Dr., Peterborough, ON K9J 7B8, Canada
| | - Sibelle Torres Vilaça
- Environmental Genomics, Instituto Tecnológico Vale, Rua Boaventura da Silva, 955, Belém 66055-090, PA, Brazil
| | - Joe-Felix Bienentreu
- Department of Biology, Laurentian University, 935 Ramsey Lake Rd, Sudbury, ON P3E 2C6, Canada
| | | | - David Lesbarrères
- Department of Biology, Laurentian University, 935 Ramsey Lake Rd, Sudbury, ON P3E 2C6, Canada
- Environment and Climate Change Canada, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Craig R Brunetti
- Department of Biology, Trent University, 1600 West Bank Dr., Peterborough, ON K9J 7B8, Canada
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Kim J, Sung HW, Jung TS, Park J, Park D. First Report of Endemic Frog Virus 3 (FV3)-like Ranaviruses in the Korean Clawed Salamander ( Onychodactylus koreanus) in Asia. Viruses 2024; 16:675. [PMID: 38793557 PMCID: PMC11125952 DOI: 10.3390/v16050675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024] Open
Abstract
Frog virus 3 (FV3) in the genus Ranavirus of the family Iridoviridae causes mass mortality in both anurans and urodeles worldwide; however, the phylogenetic origin of FV3-like ranaviruses is not well established. In Asia, three FV3-like ranaviruses have been reported in farmed populations of amphibians and reptiles. Here, we report the first case of endemic FV3-like ranavirus infections in the Korean clawed salamander Onychodactylus koreanus, caught in wild mountain streams in the Republic of Korea (ROK), through whole-genome sequencing and phylogenetic analysis. Two isolated FV3-like ranaviruses (Onychodactylus koreanus ranavirus, OKRV1 and 2) showed high similarity with the Rana grylio virus (RGV, 91.5%) and Rana nigromaculata ranavirus (RNRV, 92.2%) but relatively low similarity with the soft-shelled turtle iridovirus (STIV, 84.2%) in open reading frame (ORF) comparisons. OKRV1 and 2 formed a monophyletic clade with previously known Asian FV3-like ranaviruses, a sister group of the New World FV3-like ranavirus clade. Our results suggest that OKRV1 and 2 are FV3-like ranaviruses endemic to the ROK, and RGV and RNRV might also be endemic strains in China, unlike previous speculation. Our data have great implications for the study of the phylogeny and spreading routes of FV3-like ranaviruses and suggest the need for additional detection and analysis of FV3-like ranaviruses in wild populations in Asian countries.
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Affiliation(s)
- Jongsun Kim
- Division of Science Education, Kangwon National University, Chuncheon 24341, Republic of Korea; (J.K.); (J.P.)
| | - Haan Woo Sung
- College of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea;
| | - Tae Sung Jung
- College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Republic of Korea;
| | - Jaejin Park
- Division of Science Education, Kangwon National University, Chuncheon 24341, Republic of Korea; (J.K.); (J.P.)
| | - Daesik Park
- Division of Science Education, Kangwon National University, Chuncheon 24341, Republic of Korea; (J.K.); (J.P.)
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3
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Apakupakul K, Duncan M, Subramaniam K, Brenn-White M, Palmer JL, Viadanna PHO, Vann JA, Adamovicz L, Waltzek TB, Deem SL. Ranavirus (Frog Virus 3) Infection in Free-Living Three-Toed Box Turtles (Terrapene mexicana triunguis) in Missouri, USA. J Wildl Dis 2024; 60:151-163. [PMID: 37921651 DOI: 10.7589/jwd-d-23-00057] [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] [Received: 04/03/2023] [Accepted: 07/28/2023] [Indexed: 11/04/2023]
Abstract
Frog virus 3 (FV3) and related ranaviruses are emerging infectious disease threats to ectothermic vertebrate species globally. Although the impact of these viruses on amphibian health is relatively well studied, less is understood about their effects on reptile health. We report two cases of FV3 infection, 11 mo apart, in three-toed box turtles (Terrapene mexicana triunguis) from a wildlife rehabilitation center. Case 1 had upper respiratory signs upon intake but had no clinical signs at the time of euthanasia 1 mo later. Case 2 presented for vehicular trauma, had ulcerative pharyngitis and glossitis, and died overnight. In case 1, we detected FV3 nucleic acid with qPCR in oral swabs, kidney, liver, spleen, and tongue. In case 2, we detected FV3 in an oral swab, an oral plaque, heart, kidney, lung, liver, spleen, and tongue. We also detected FV3 nucleic acid with in situ hybridization for case 2. For both cases, FV3 was isolated in cell culture and identified with DNA sequencing. Histopathologic examination of postmortem tissue from case 1 was unremarkable, whereas acute hemorrhagic pneumonia and splenic necrosis were noted in case 2. The difference in clinical signs between the two cases may have been due to differences in the temporal course of FV3 disease at the time of necropsy. Failure to detect this infection previously in Missouri reptiles may be due to lack of surveillance, although cases may also represent a novel spillover to box turtles in Missouri. Our findings reiterate previous suggestions that the range of FV3 infection may be greater than previously documented and that infection may occur in host species yet to be tested.
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Affiliation(s)
- Kathleen Apakupakul
- Saint Louis Zoo Institute for Conservation Medicine, 1 Government Dr., St. Louis, Missouri 63110, USA
| | - Mary Duncan
- Saint Louis Zoo Department of Animal Health, 1 Government Dr., St. Louis, Missouri 63110, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, 2187 Mowry Rd., Bldg. 0471, Gainesville, Florida 32611, USA
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd., Gainesville, Florida 32610, USA
| | - Maris Brenn-White
- Saint Louis Zoo Institute for Conservation Medicine, 1 Government Dr., St. Louis, Missouri 63110, USA
| | - Jamie L Palmer
- Saint Louis Zoo Institute for Conservation Medicine, 1 Government Dr., St. Louis, Missouri 63110, USA
| | - Pedro H O Viadanna
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, 2187 Mowry Rd., Bldg. 0471, Gainesville, Florida 32611, USA
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd., Gainesville, Florida 32610, USA
| | - Jordan A Vann
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, 2187 Mowry Rd., Bldg. 0471, Gainesville, Florida 32611, USA
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd., Gainesville, Florida 32610, USA
| | - Laura Adamovicz
- Wildlife Epidemiology Laboratory, University of Illinois College of Veterinary Medicine, 2001 S. Lincoln Ave., Urbana, Illinois 61802, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, 2187 Mowry Rd., Bldg. 0471, Gainesville, Florida 32611, USA
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd., Gainesville, Florida 32610, USA
- Current affiliation: Washington Animal Disease Diagnostic Laboratory and Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647034, Pullman, Washington, USA
| | - Sharon L Deem
- Saint Louis Zoo Institute for Conservation Medicine, 1 Government Dr., St. Louis, Missouri 63110, USA
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4
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Parry RH, Slonchak A, Campbell LJ, Newton ND, Debat HJ, Gifford RJ, Khromykh AA. A novel tamanavirus ( Flaviviridae) of the European common frog ( Rana temporaria) from the UK. J Gen Virol 2023; 104:001927. [PMID: 38059479 PMCID: PMC10770923 DOI: 10.1099/jgv.0.001927] [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] [Received: 07/07/2023] [Accepted: 11/19/2023] [Indexed: 12/08/2023] Open
Abstract
Flavivirids are small, enveloped, positive-sense RNA viruses from the family Flaviviridae with genomes of ~9-13 kb. Metatranscriptomic analyses of metazoan organisms have revealed a diversity of flavivirus-like or flavivirid viral sequences in fish and marine invertebrate groups. However, no flavivirus-like virus has been identified in amphibians. To remedy this, we investigated the virome of the European common frog (Rana temporaria) in the UK, utilizing high-throughput sequencing at six catch locations. De novo assembly revealed a coding-complete virus contig of a novel flavivirid ~11.2 kb in length. The virus encodes a single ORF of 3456 aa and 5' and 3' untranslated regions (UTRs) of 227 and 666 nt, respectively. We named this virus Rana tamanavirus (RaTV), as BLASTp analysis of the polyprotein showed the closest relationships to Tamana bat virus (TABV) and Cyclopterus lumpus virus from Pteronotus parnellii and Cyclopterus lumpus, respectively. Phylogenetic analysis of the RaTV polyprotein compared to Flavivirus and Flavivirus-like members indicated that RaTV was sufficiently divergent and basal to the vertebrate Tamanavirus clade. In addition to the Mitcham strain, partial but divergent RaTV, sharing 95.64-97.39 % pairwise nucleotide identity, were also obtained from the Poole and Deal samples, indicating that RaTV is widespread in UK frog samples. Bioinformatic analyses of predicted secondary structures in the 3'UTR of RaTV showed the presence of an exoribonuclease-resistant RNA (xrRNA) structure standard in flaviviruses and TABV. To examine this biochemically, we conducted an in vitro Xrn1 digestion assay showing that RaTV probably forms a functional Xrn1-resistant xrRNA.
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Affiliation(s)
- Rhys H. Parry
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Andrii Slonchak
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre (AIDRC), Brisbane, QLD, Australia
| | - Lewis J. Campbell
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
- Institute of Zoology, Zoological Society of London, London, UK
- Environment and Sustainability Institute, University of Exeter, Penryn, UK
| | - Natalee D. Newton
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre (AIDRC), Brisbane, QLD, Australia
| | - Humberto J. Debat
- Instituto de Patología Vegetal, Centro de Investigaciones Agropecuarias, Instituto Nacional de Tecnología Agropecuaria (IPAVE-CIAP-INTA), Córdoba X5020ICA, Argentina
- Unidad de Fitopatología y Modelización Agrícola (UFYMA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba X5020ICA, Argentina
| | | | - Alexander A. Khromykh
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre (AIDRC), Brisbane, QLD, Australia
- AIDRC Global Virus Network Centre of Excellence, Brisbane, QLD, Australia
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5
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Hughey MC, Warne R, Dulmage A, Reeve RE, Curtis GH, Whitfield K, Schock DM, Crespi E. Diet- and salinity-induced modifications of the gut microbiota are associated with differential physiological responses to ranavirus infection in Rana sylvatica. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220121. [PMID: 37305908 PMCID: PMC10258663 DOI: 10.1098/rstb.2022.0121] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 03/26/2023] [Indexed: 06/13/2023] Open
Abstract
Greater knowledge of how host-microbiome interactions vary with anthropogenic environmental change and influence pathogenic infections is needed to better understand stress-mediated disease outcomes. We investigated how increasing salinization in freshwaters (e.g. due to road de-icing salt runoff) and associated increases in growth of nutritional algae influenced gut bacterial assembly, host physiology and responses to ranavirus exposure in larval wood frogs (Rana sylvatica). Elevating salinity and supplementing a basic larval diet with algae increased larval growth and also increased ranavirus loads. However, larvae given algae did not exhibit elevated kidney corticosterone levels, accelerated development or weight loss post-infection, whereas larvae fed a basic diet did. Thus, algal supplementation reversed a potentially maladaptive stress response to infection observed in prior studies in this system. Algae supplementation also reduced gut bacterial diversity. Notably, we observed higher relative abundances of Firmicutes in treatments with algae-a pattern consistent with increased growth and fat deposition in mammals-that may contribute to the diminished stress responses to infection via regulation of host metabolism and endocrine function. Our study informs mechanistic hypotheses about the role of microbiome mediation of host responses to infection that can be tested in future experiments in this host-pathogen system. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
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Affiliation(s)
- Myra C. Hughey
- Department of Biology, Vassar College, Poughkeepsie, NY 12604, USA
| | - Robin Warne
- School of Biological Sciences, Southern Illinois University, Carbondale, IL 62901, USA
| | - Alexa Dulmage
- School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Robyn E. Reeve
- School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Grace H. Curtis
- School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Kourtnie Whitfield
- School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | | | - Erica Crespi
- School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
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6
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Assis VR, Robert J, Titon SCM. Introduction to the special issue Amphibian immunity: stress, disease and ecoimmunology. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220117. [PMID: 37305915 PMCID: PMC10258669 DOI: 10.1098/rstb.2022.0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Amphibian populations have been declining worldwide, with global climate changes and infectious diseases being among the primary causes of this scenario. Infectious diseases are among the primary drivers of amphibian declines, including ranavirosis and chytridiomycosis, which have gained more attention lately. While some amphibian populations are led to extinction, others are disease-resistant. Although the host's immune system plays a major role in disease resistance, little is known about the immune mechanisms underlying amphibian disease resistance and host-pathogen interactions. As ectotherms, amphibians are directly subjected to changes in temperature and rainfall, which modulate stress-related physiology, including immunity and pathogen physiology associated with diseases. In this sense, the contexts of stress, disease and ecoimmunology are essential for a better understanding of amphibian immunity. This issue brings details about the ontogeny of the amphibian immune system, including crucial aspects of innate and adaptive immunity and how ontogeny can influence amphibian disease resistance. In addition, the papers in the issue demonstrate an integrated view of the amphibian immune system associated with the influence of stress on immune-endocrine interactions. The collective body of research presented herein can provide valuable insights into the mechanisms underlying disease outcomes in natural populations, particularly in the context of changing environmental conditions. These findings may ultimately enhance our ability to forecast effective conservation strategies for amphibian populations. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
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Affiliation(s)
- Vania Regina Assis
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-900 São Paulo, Brazil
- College of Public Health, University of South Florida, Tampa, FL 33612-9415, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642, USA
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7
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Coutinho CD, Ford CE, Trafford JD, Duarte A, Rebelo R, Rosa GM. Non-Lethal Detection of Ranavirus in Fish. Viruses 2023; 15:471. [PMID: 36851684 PMCID: PMC9964643 DOI: 10.3390/v15020471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Emergent infectious diseases have an increasing impact on both farmed animals and wildlife. The ability to screen for pathogens is critical for understanding host-pathogen dynamics and informing better management. Ranavirus is a pathogen of concern, associated with disease outbreaks worldwide, affecting a broad range of fish, amphibian, and reptile hosts, but research has been limited. The traditional screening of internal tissues, such as the liver, has been regarded as the most effective for detecting and quantifying Ranavirus. However, such methodology imposes several limitations from ethical and conservation standpoints. Non-lethal sampling methods of viral detection were explored by comparing the efficacy of both buccal swabbing and fin clipping. The study was conducted on two Iberian, threatened freshwater fish (Iberochondrostoma lusitanicum and Cobitis paludica), and all samples were screened using qPCR. While for C. paludica both methods were reliable in detecting Ranavirus, on I. lusitanicum, there was a significantly higher detection rate in buccal swabs than in fin tissue. This study, therefore, reports that fin clipping may yield false Ranavirus negatives when in small-bodied freshwater fish. Overall, buccal swabbing is found to be good as an alternative to more invasive procedures, which is of extreme relevance, particularly when dealing with a threatened species.
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Affiliation(s)
- Catarina D. Coutinho
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Charlotte E. Ford
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Joseph D. Trafford
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Ana Duarte
- Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal
- Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV), 2780-157 Oeiras, Portugal
| | - Rui Rebelo
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Gonçalo M. Rosa
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
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8
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Hardman RH, Reinert LK, Irwin KJ, Oziminski K, Rollins-Smith L, Miller DL. Disease state associated with chronic toe lesions in hellbenders may alter anti-chytrid skin defenses. Sci Rep 2023; 13:1982. [PMID: 36737574 PMCID: PMC9898527 DOI: 10.1038/s41598-023-28334-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Hellbenders (Cryptobranchus alleganiensis) are large, aquatic salamanders from the eastern United States. Both subspecies, eastern and Ozark hellbenders, have experienced declines resulting in federal listing of Ozark hellbenders. The globally distributed chytrid fungus, Batrachochytrium dendrobatidis (Bd) has been detected in both subspecies, and Batrachochytrium salamandrivorans (Bsal) poses a new threat if introduced into North America. Ozark hellbenders also suffer a high prevalence of toe lesions of unknown etiology, with changes in host immunocompetence hypothesized to contribute. Antimicrobial peptides (AMPs) secreted from dermal granular glands may play a role in hellbender health. We collected skin secretions from free-ranging hellbenders and enriched them for small cationic peptides used for growth inhibition assays against Bd and Bsal. Generalized linear mixed models revealed the presence of active toe lesions as the strongest and only significant predictor of decreased Bd inhibition by skin peptides. We also found skin secretions were more inhibitory of Bsal than Bd. MALDI-TOF mass spectrometry revealed candidate peptides responsible for anti-chytrid activity. Results support the hypothesis that hellbender skin secretions are important for innate immunity against chytrid pathogens, and decreased production or release of skin peptides may be linked to other sub-lethal effects of disease associated with toe lesions.
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Affiliation(s)
- Rebecca H Hardman
- Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, 37996, USA. .,Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, 33701, USA.
| | - Laura K Reinert
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Kelly J Irwin
- Arkansas Game and Fish Commission, Benton, AR, 72015, USA
| | - Kendall Oziminski
- Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, 37996, USA
| | - Louise Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Debra L Miller
- Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, 37996, USA.,School of Natural of Resources, University of Tennessee, Knoxville, Tennessee, 37996, USA
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9
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Peñafiel-Ricaurte A, Price SJ, Leung WTM, Alvarado-Rybak M, Espinoza-Zambrano A, Valdivia C, Cunningham AA, Azat C. Is Xenopus laevis introduction linked with Ranavirus incursion, persistence and spread in Chile? PeerJ 2023; 11:e14497. [PMID: 36874973 PMCID: PMC9979829 DOI: 10.7717/peerj.14497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 11/10/2022] [Indexed: 03/03/2023] Open
Abstract
Ranaviruses have been associated with amphibian, fish and reptile mortality events worldwide and with amphibian population declines in parts of Europe. Xenopus laevis is a widespread invasive amphibian species in Chile. Recently, Frog virus 3 (FV3), the type species of the Ranavirus genus, was detected in two wild populations of this frog near Santiago in Chile, however, the extent of ranavirus infection in this country remains unknown. To obtain more information about the origin of ranavirus in Chile, its distribution, species affected, and the role of invasive amphibians and freshwater fish in the epidemiology of ranavirus, a surveillance study comprising wild and farmed amphibians and wild fish over a large latitudinal gradient (2,500 km) was carried out in 2015-2017. In total, 1,752 amphibians and 496 fish were tested using a ranavirus-specific qPCR assay, and positive samples were analyzed for virus characterization through whole genome sequencing of viral DNA obtained from infected tissue. Ranavirus was detected at low viral loads in nine of 1,011 X. laevis from four populations in central Chile. No other amphibian or fish species tested were positive for ranavirus, suggesting ranavirus is not threatening native Chilean species yet. Phylogenetic analysis of partial ranavirus sequences showed 100% similarity with FV3. Our results show a restricted range of ranavirus infection in central Chile, coinciding with X. laevis presence, and suggest that FV3 may have entered the country through infected X. laevis, which appears to act as a competent reservoir host, and may contribute to the spread the virus locally as it invades new areas, and globally through the pet trade.
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Affiliation(s)
- Alexandra Peñafiel-Ricaurte
- Sustainability Research Centre & PhD in Conservation Medicine Program, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, United Kingdom
| | | | - William T M Leung
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Mario Alvarado-Rybak
- Sustainability Research Centre & PhD in Conservation Medicine Program, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, United Kingdom.,Núcleo de Ciencias Aplicadas en Ciencias Veterinarias y Agronómicas, Facultad de Medicina Veterinaria y Agronomía, Universidad de las Américas, Santiago, Chile
| | - Andrés Espinoza-Zambrano
- Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Catalina Valdivia
- Sustainability Research Centre & PhD in Conservation Medicine Program, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
| | | | - Claudio Azat
- Sustainability Research Centre & PhD in Conservation Medicine Program, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
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10
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Strachinis I, Marschang RE, Lymberakis P, Karagianni KM, Azmanis P. Infectious disease threats to amphibians in Greece: new localities positive for Batrachochytrium dendrobatidis. DISEASES OF AQUATIC ORGANISMS 2022; 152:127-138. [PMID: 36519684 DOI: 10.3354/dao03712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In the early 2000s, numerous cases of European amphibian population declines and mass die-offs started to emerge. Investigating those events led to the discovery that wild European amphibians were confronted with grave disease threats caused by introduced pathogens, namely the amphibian and the salamander chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal) and ranaviruses. In Greece, Bd was previously documented among wild amphibian populations in 2 different locations and 3 different species. However, no disease-related mass declines or mortality events have been reported. In this work, we build upon previous findings with new, subsequently obtained data, resulting in a 225-sample dataset of 14 species from 17 different locations throughout Greece, in order to examine the occurrence status of all 3 pathogens responsible for emerging infectious diseases in European amphibians. No positive samples for Bsal or ranavirus were recorded in any location. We confirmed the presence of Bd in 4 more localities and in 4 more species, including 1 urodelan (Macedonian crested newt Triturus macedonicus) and 1 introduced anuran (American bullfrog Lithobates catesbeianus). All insular localities were negative for Bd, except for Crete, where Bd was identified in 2 different locations. Again, no mass declines or die-offs were recorded in any Bd-positive area or elsewhere. However, given the persistence of Bd across Greece over the past ~20 yr, monitoring efforts should continue, and ideally be further expanded.
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Affiliation(s)
- Ilias Strachinis
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Natural Sciences, Aristotle University of Thessaloniki, 54636, Greece
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11
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Ford CE, Brookes LM, Skelly E, Sergeant C, Jordine T, Balloux F, Nichols RA, Garner TWJ. Non-Lethal Detection of Frog Virus 3-Like (RUK13) and Common Midwife Toad Virus-Like (PDE18) Ranaviruses in Two UK-Native Amphibian Species. Viruses 2022; 14:v14122635. [PMID: 36560639 PMCID: PMC9786228 DOI: 10.3390/v14122635] [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: 10/25/2022] [Revised: 11/18/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Ranaviruses have been involved in amphibian mass mortality events worldwide. Effective screening to control this pathogen is essential; however, current sampling methods are unsuitable for the detection of subclinical infections. Non-lethal screening is needed to prevent both further spread of ranavirus and losses of at-risk species. To assess non-lethal sampling methods, we conducted two experiments: bath exposing common frogs to RUK13 ranavirus at three concentrations, and exposing common toads to RUK13 or PDE18. Non-lethal sampling included buccal, digit, body and tank swabs, along with toe clips and stool taken across three time-points post-exposure. The presence/load of ranavirus was examined using quantitative PCR in 11 different tissues obtained from the same euthanised animals (incl. liver, gastro-intestinal tract and kidney). Buccal swab screening had the highest virus detection rate in both species (62% frogs; 71% toads) and produced consistently high virus levels compared to other non-lethal assays. The buccal swab was effective across multiple stages of infection and differing infection intensities, though low levels of infection were more difficult to detect. Buccal swab assays competed with, and even outperformed, lethal sampling in frogs and toads, respectively. Successful virus detection in the absence of clinical signs was observed (33% frogs; 50% toads); we found no difference in detectability for RUK13 and PDE18. Our results suggest that buccal swabbing could replace lethal sampling for screening and be introduced as standard practice for ranavirus surveillance.
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Affiliation(s)
- Charlotte E. Ford
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
- UCL Genetics Institute, University College London, Gower Street, London WC1E 6BT, UK
- Correspondence: or
| | - Lola M. Brookes
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
- RVC Animal Welfare Science and Ethics, The Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK
| | - Emily Skelly
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
| | - Chris Sergeant
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
| | - Tresai Jordine
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
| | - Francois Balloux
- UCL Genetics Institute, University College London, Gower Street, London WC1E 6BT, UK
| | - Richard A. Nichols
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Trenton W. J. Garner
- Zoological Society of London, Institute of Zoology, Nuffield Building, Outer Circle, London NW8 7LS, UK
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12
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Allain SJR, Duffus ALJ, Marschang RE. Editorial: Emerging infections and diseases of herpetofauna. Front Vet Sci 2022; 9:909616. [PMID: 36238439 PMCID: PMC9552943 DOI: 10.3389/fvets.2022.909616] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Steven J. R. Allain
- Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, United Kingdom
| | - Amanda L. J. Duffus
- Health of Herpetofauna Communities Research Group, Department of Natural Sciences, Gordon State College, Barnesville, GA, United States
- *Correspondence: Amanda L. J. Duffus
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13
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Zhao R, Gu C, Zou X, Zhao M, Xiao W, He M, He L, Yang Q, Geng Y, Yu Z. Comparative genomic analysis reveals new evidence of genus boundary for family Iridoviridae and explores qualified hallmark genes. Comput Struct Biotechnol J 2022; 20:3493-3502. [PMID: 35860404 PMCID: PMC9284377 DOI: 10.1016/j.csbj.2022.06.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 11/25/2022] Open
Abstract
Members of the family Iridoviridae (iridovirids) are globally distributed and trigger adverse economic and ecological impacts on aquaculture and wildlife. Iridovirids taxonomy has previously been studied based on a limited number of genomes, but this is not suitable for the current and future virological studies as more iridovirids are emerging. In our study, 57 representative iridovirids genomes were selected from a total of 179 whole genomes available on NCBI. Then 18 core genes were screened out for members of the family Iridoviridae. Average amino acid sequence identity (AAI) analysis indicated that a cut-off value of 70% is more suitable for the current iridovirids genome database than ICTV-defined 50% threshold to better clarify viral genus boundaries. In addition, more subgroups were divided at genus level with the AAI threshold of 70%. This observation was further confirmed by genomic synteny analysis, codon usage preference analysis, genome GC content and length analysis, and phylogenic analysis. According to the pairwise comparison analysis of core genes, 9 hallmark genes were screened out to conduct preliminary identification and investigation at the genus level of iridovirids in a more convenient and economical manner.
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Affiliation(s)
- Ruoxuan Zhao
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Congwei Gu
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | | | - Mingde Zhao
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | - Wudian Xiao
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | - Manli He
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | - Lvqin He
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | - Qian Yang
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China
| | - Yi Geng
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Zehui Yu
- Laboratory Animal Center, Southwest Medical University, Luzhou, Sichuan, PR China.,Luzhou Key Laboratory for Model Animal and Human Disease Research, PR China.,Scholl of Basic Medical Sciences, Zhejiang University, Hangzhou, PR China
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14
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Roh N, Park J, Kim J, Kwon H, Park D. Prevalence of Ranavirus Infection in Three Anuran Species across South Korea. Viruses 2022; 14:v14051073. [PMID: 35632814 PMCID: PMC9148164 DOI: 10.3390/v14051073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 12/13/2022] Open
Abstract
To cope with amphibian die-offs caused by ranavirus, it is important to know the underlying ranavirus prevalence in a region. We studied the ranavirus prevalence in tadpoles of two native and one introduced anuran species inhabiting agricultural and surrounding areas at 49 locations across eight provinces of South Korea by applying qPCR. The local ranavirus prevalence and the individual infection rates at infected locations were 32.6% and 16.1%, respectively, for Dryophytes japonicus (Japanese tree frog); 25.6% and 26.1% for Pelophylax nigromaculatus (Black-spotted pond frog); and 30.5% and 50.0% for Lithobates catesbeianus (American bullfrog). The individual infection rate of L. catesbeianus was significantly greater than that of D. japonicus. The individual infection rate of P. nigromaculatus was related to the site-specific precipitation and air temperature. The individual infection rate gradually increased from Gosner development stage 39, and intermittent infection was confirmed in the early and middle developmental stages. Our results show that ranavirus is widespread among wild amphibians living in agricultural areas of South Korea, and mass die-offs by ranavirus could occur at any time.
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Affiliation(s)
- Namho Roh
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Kangwon, Korea;
| | - Jaejin Park
- Division of Science Education, Kangwon National University, Chuncheon 24341, Kangwon, Korea; (J.P.); (J.K.); (H.K.)
| | - Jongsun Kim
- Division of Science Education, Kangwon National University, Chuncheon 24341, Kangwon, Korea; (J.P.); (J.K.); (H.K.)
| | - Hyerim Kwon
- Division of Science Education, Kangwon National University, Chuncheon 24341, Kangwon, Korea; (J.P.); (J.K.); (H.K.)
| | - Daesik Park
- Division of Science Education, Kangwon National University, Chuncheon 24341, Kangwon, Korea; (J.P.); (J.K.); (H.K.)
- Correspondence: ; Tel.: +82-33-250-6739; Fax: +82-33-259-5600
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15
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Herath J, Ellepola G, Meegaskumbura M. Patterns of infection, origins, and transmission of ranaviruses among the ectothermic vertebrates of Asia. Ecol Evol 2021; 11:15498-15519. [PMID: 34824771 PMCID: PMC8601927 DOI: 10.1002/ece3.8243] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/23/2021] [Accepted: 09/27/2021] [Indexed: 01/03/2023] Open
Abstract
Ranaviral infections, a malady of ectothermic vertebrates, are becoming frequent, severe, and widespread, causing mortality among both wild and cultured species, raising odds of species extinctions and economic losses. This increase in infection is possibly due to the broad host range of ranaviruses and the transmission of these pathogens through regional and international trade in Asia, where outbreaks have been increasingly reported over the past decade. Here, we focus attention on the origins, means of transmission, and patterns of spread of this infection within the region. Infections have been recorded in both cultured and wild populations in at least nine countries/administrative regions, together with mass die-offs in some regions. Despite the imminent seriousness of the disease in Asia, surveillance efforts are still incipient. Some of the viral strains within Asia may transmit across host-taxon barriers, posing a significant risk to native species. Factors such as rising temperatures due to global climate change seem to exacerbate ranaviral activity, as most known outbreaks have been recorded during summer; however, data are still inadequate to verify this pattern for Asia. Import risk analysis, using protocols such as Pandora+, pre-border pathogen screening, and effective biosecurity measures, can be used to mitigate introduction of ranaviruses to uninfected areas and curb transmission within Asia. Comprehensive surveillance using molecular diagnostic tools for ranavirus species and variants will help in understanding the prevalence and disease burden in the region. This is an important step toward conserving native biodiversity and safeguarding the aquaculture industry.
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Affiliation(s)
- Jayampathi Herath
- College of ForestryGuangxi Key Lab for Forest Ecology and ConservationGuangxi UniversityNanningChina
| | - Gajaba Ellepola
- College of ForestryGuangxi Key Lab for Forest Ecology and ConservationGuangxi UniversityNanningChina
- Department of ZoologyFaculty of ScienceUniversity of PeradeniyaKandySri Lanka
| | - Madhava Meegaskumbura
- College of ForestryGuangxi Key Lab for Forest Ecology and ConservationGuangxi UniversityNanningChina
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16
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Bosch J, Mora-Cabello de Alba A, Marquínez S, Price SJ, Thumsová B, Bielby J. Long-Term Monitoring of Amphibian Populations of a National Park in Northern Spain Reveals Negative Persisting Effects of Ranavirus, but Not Batrachochytrium dendrobatidis. Front Vet Sci 2021; 8:645491. [PMID: 34235196 PMCID: PMC8255480 DOI: 10.3389/fvets.2021.645491] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/21/2021] [Indexed: 11/25/2022] Open
Abstract
Amphibians are the most highly threatened vertebrates, and emerging pathogens are a serious threat to their conservation. Amphibian chytrid fungi and the viruses of the Ranavirus genus are causing disease outbreaks worldwide, including in protected areas such as National Parks. However, we lack information about their effect over amphibian populations in the long-term, and sometimes these mortality episodes are considered as transient events without serious consequences over longer time-spans. Here, we relate the occurrence of both pathogens with the population trends of 24 amphibian populations at 15 sites across a national Park in northern Spain over a 14-year period. Just one out 24 populations presents a positive population trend being free of both pathogens, while seven populations exposed to one or two pathogens experienced strong declines during the study period. The rest of the study populations (16) remain stable, and these tend to be of species that are not susceptible to the pathogen present or are free of pathogens. Our study is consistent with infectious diseases playing an important role in dictating amphibian population trends and emphasizes the need to adopt measures to control these pathogens in nature. We highlight that sites housing species carrying Ranavirus seems to have experienced more severe population-level effects compared to those with the amphibian chytrid fungus, and that ranaviruses could be just as, or more important, other more high-profile amphibian emerging pathogens.
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Affiliation(s)
- Jaime Bosch
- Research Unit of Biodiversity (Consejo Superior de Investigaciones Científicas, Universidad de Oviedo, Principado de Asturias), Oviedo University, Mieres, Spain.,Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | | | | | - Stephen J Price
- Genetic Institute, University College London, London, United Kingdom
| | - Barbora Thumsová
- Research Unit of Biodiversity (Consejo Superior de Investigaciones Científicas, Universidad de Oviedo, Principado de Asturias), Oviedo University, Mieres, Spain.,Museo Nacional de Ciencias Naturales-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Jon Bielby
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, United Kingdom
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17
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TLR5-Mediated Reactivation of Quiescent Ranavirus FV3 in Xenopus Peritoneal Macrophages. J Virol 2021; 95:JVI.00215-21. [PMID: 33827949 DOI: 10.1128/jvi.00215-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/28/2021] [Indexed: 12/25/2022] Open
Abstract
Ranaviruses such as frog virus 3 (FV3) are large double-stranded DNA (dsDNA) viruses causing emerging infectious diseases leading to extensive morbidity and mortality of amphibians and other ectothermic vertebrates worldwide. Among the hosts of FV3, some are highly susceptible, whereas others are resistant and asymptomatic carriers that can take part in disseminating the infectious virus. To date, the mechanisms involved in the processes of FV3 viral persistence associated with subclinical infection transitioning to lethal outbreaks remain unknown. Investigation in Xenopus laevis has revealed that in asymptomatic FV3 carrier animals, inflammation induced by heat-killed (HK) Escherichia coli stimulation can provoke the relapse of active infection. Since Toll-like receptors (TLRs) are critical for recognizing microbial molecular patterns, we investigated their possible involvement in inflammation-induced FV3 reactivation. Among the 10 different TLRs screened for changes in expression levels following FV3 infection and HK E. coli stimulation, only TLR5 and TLR22, both of which recognize bacterial products, showed differential expression, and only the TLR5 ligand flagellin was able to induce FV3 reactivation similarly to HK E. coli Furthermore, only the TLR5 ligand flagellin induced FV3 reactivation in peritoneal macrophages both in vitro and in vivo These data indicate that the TLR5 signaling pathway can trigger FV3 reactivation and suggest a role of secondary bacterial infections or microbiome alterations (stress or pollution) in initiating sudden deadly disease outbreaks in amphibian populations with detectable persistent asymptomatic ranavirus.IMPORTANCE This study in the amphibian Xenopus laevis provides new evidence of the critical role of macrophages in the persistence of ranaviruses in a quiescent state as well as in the reactivation of these pathogens into a virulent infection. Among the multiple microbial sensors expressed by macrophages, our data underscore the preponderant involvement of TLR5 stimulation in triggering the reactivation of quiescent FV3 in resident peritoneal macrophages, unveiling a mechanistic connection between the reactivation of persisting ranavirus infection and bacterial coinfection. This suggests a role for secondary bacterial infections or microbiome alterations (stress or pollution) in initiating sudden deadly disease outbreaks in amphibian populations with detectable persistent asymptomatic ranavirus.
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18
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Bielby J, Price SJ, Monsalve-CarcaÑo C, Bosch J. Host contribution to parasite persistence is consistent between parasites and over time, but varies spatially. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02256. [PMID: 33164249 DOI: 10.1002/eap.2256] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/11/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
Most parasites and pathogens infect multiple hosts, but a great deal of variation exists in the role of those hosts in persistence of infection. Understanding which hosts are most important in maintaining parasites can provide a clearer target for infection control. Recently developed empirical and theoretical approaches provide a way to quantify the relative contribution of hosts within a community and place them in a multi-host framework to better direct control efforts. Amphibians provide a framework for better understanding multi-host-multi-parasite dynamics. Two well-studied amphibian parasites, Batrachochytrium dendrobatidis (Bd) and Ranavirus, infect multiple host species and exhibit a great deal of heterogeneity in how they affect hosts. We used these two parasites and a community of five amphibian species to investigate the relative importance of hosts in parasite persistence, and how any patterns varied spatially and temporally. At two sites (Lake Ercina and Lake Lloroza in the Picos de Europa National Park, Spain) we collected data on the prevalence and shedding rate of parasite infection for both Bd and Ranavirus, and the abundance of each species' life stages. We used these data to parameterize a recently developed modeling framework, which was used to quantify the relative contribution of each host to the community reproductive number, R0 . By comparing each host-category over time and between sites we were able to identify consistencies in which host was responsible for the maintenance of these two parasites. Within a site one species consistently contributed the most to the persistence of both parasites. This consistency did not transfer between sites, the maintenance host species being different for each. At one site (Ercina), life stages of the common midwife toad, Alytes obstetricans, acted as the maintenance host for both Bd and Ranavirus. In contrast, at the second site, Lloroza, the alpine newt, Ichthyosaura alpestris, fulfilled that role. A single host species was responsible for infection persistence of both parasites at each lake. Attempts to control the infection levels and impacts of multiple parasites can benefit from a community epidemiology approach, and provide clarity on which hosts are the foci of mitigation efforts. However, at a small spatial scale, the target host may vary according to the physical qualities of those sites and the demographics of the host community.
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Affiliation(s)
- Jon Bielby
- School of Natural Sciences and Psychology, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool, L3 3AF, United Kingdom
| | - Stephen J Price
- UCL Genetics Institute, Darwin Building, Gower Street, London, WC1E 6BT, United Kingdom
- Institute of Zoology, Zoological Society of London, Regents Park, London, NW1 4RY, United Kingdom
| | | | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, Madrid, 28006, Spain
- Research Unit of Biodiversity (CSIC, UO, PA), Oviedo University-Campus Mieres, Mieres, Spain
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19
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Trojan hosts: the menace of invasive vertebrates as vectors of pathogens in the Southern Cone of South America. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02488-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Wynne FJ, Puschendorf R, Knight ME, Price SJ. Choice of molecular assay determines ranavirus detection probability and inferences about prevalence and occurrence. DISEASES OF AQUATIC ORGANISMS 2020; 141:139-147. [PMID: 32969346 DOI: 10.3354/dao03518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ranaviruses are emerging pathogens that can cause morbidity, mortality and population declines in ectothermic hosts; however, there is no standardized approach to diagnostics. Here, we compared the inter-assay variation and intra-assay precision among 2 commonly used quantitative PCRs (qPCRs), a conventional and a nested PCR assay (used as a gold standard), using laboratory-propagated ranavirus (FV3 and CMTV) and field-collected samples. A qPCR assay ('Leung') detected viral DNA in dilutions 2 orders of magnitude lower than other assays regardless of the viral lineage of the cultured isolate (FV3/CMTV). The second qPCR ('Brunner') was slightly more sensitive than the conventional PCR ('Mao' assay). For field samples, the Leung qPCR detected all known positives, while the Mao assay PCR only detected 2.5% of the positive samples. Amplicon sequences from the 2 conventional PCRs were shown to be useful for inferring viral lineage. Inaccurate results will bias estimates of the distribution and prevalence of ranaviruses, and together these findings emphasize that molecular assays should be chosen carefully in the context of study aims.
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Affiliation(s)
- Felicity J Wynne
- School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, UK
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21
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von Essen M, Leung WTM, Bosch J, Pooley S, Ayres C, Price SJ. High pathogen prevalence in an amphibian and reptile assemblage at a site with risk factors for dispersal in Galicia, Spain. PLoS One 2020; 15:e0236803. [PMID: 32730306 PMCID: PMC7392302 DOI: 10.1371/journal.pone.0236803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 07/14/2020] [Indexed: 12/30/2022] Open
Abstract
Ranaviruses are agents of disease, mortality and population declines in ectothermic vertebrates and emergences have been repeatedly linked to human activities. Ranaviruses in the common midwife toad ranavirus lineage are emerging in Europe. They are known to be severe multi-host pathogens of amphibians and can also cause disease in reptiles. Recurrent outbreaks of ranavirus disease and mortality affecting three species have occurred at a small reservoir in north-west Spain but no data were available on occurrence of the pathogen in the other amphibian and reptile species present or at adjacent sites. We sampled nine species of amphibians and reptiles at the reservoir and nearby sites and screened for ranavirus presence using molecular methods. Our results show infection with ranavirus in all nine species, including first reports for Hyla molleri, Pelophylax perezi, Rana iberica, and Podarcis bocagei. We detected ranavirus in all four local sites and confirmed mass mortality incidents involving Lissotriton boscai and Triturus marmoratus were ongoing. The reservoir regularly hosts water sports tournaments and the risks of ranavirus dispersal through the translocation of contaminated equipment are discussed.
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Affiliation(s)
- Marius von Essen
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
- Imperial College London, Department of Life Sciences (Silwood Park), Ascot, United Kingdom
| | - William T. M. Leung
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- Research Unit of Biodiversity—CSIC/UO/PA, Universidad de Oviedo, Edificio de Investigación, Mieres, Spain
- * E-mail:
| | - Simon Pooley
- Imperial College London, Department of Life Sciences (Silwood Park), Ascot, United Kingdom
| | - Cesar Ayres
- Asociación Herpetológica Española, Madrid, Spain
| | - Stephen J. Price
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
- UCL Genetics Institute, London, United Kingdom
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22
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Ballard D, Davis A, Fuller R, Garner A, Mileham A, Serna J, Brue D, Harding C, Dodgen C, Culpepper W, Piatt B, Rosario S, Duffus A. An examination of the Iridovirus core genes for reconstructing Ranavirus phylogenies. Facets (Ott) 2020. [DOI: 10.1139/facets-2020-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are globally emerging infections of poikilothermic vertebrates and belong to the viral family Iridoviridae. The six species of ranaviruses are responsible for unknown numbers of infections and disease and mortality events around the world in amphibians, fish, and reptiles. Genomic investigations have shown that there are 24 core genes shared by all iridoviruses. In this study, we examine the utility of each of these genes in reconstructing phylogenetic relationships across six species of Ranavirus. We also performed dot-plot analysis for the 17 isolates in the study. For large-scale differentiation, using the major capsid protein gene creates a tree similar to the whole genome tree. Other comparable genes include open reading frame (ORF) 19R (a serine–theonine protein kinase) and ORF 88R (Erv I/Alr Family protein). The poorest candidate for phylogenetic reconstruction, due to high homology, was ORF 1R (a putative replication factor and (or) DNA binding-packing protein). There are a plethora of genes that may be useful to examine phylogenies at smaller scales (e.g., to examine local adaptation); however, they do not necessarily belong to the set of highly conserved core genes.
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Affiliation(s)
- D.R. Ballard
- Department of Mathematics and Computer Sciences, School of Arts and Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - A.J. Davis
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - R.B. Fuller
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - A.R. Garner
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - A.D. Mileham
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - J.D. Serna
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - D.E. Brue
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - C.M. Harding
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - C.D. Dodgen
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - W. Culpepper
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - B. Piatt
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
| | - S.E. Rosario
- Science Division, Valencia College, Orlando, FL 32802, USA
| | - A.L.J. Duffus
- Department of Natural Sciences, School of Nursing, Health, and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
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23
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Campbell LJ, Pawlik AH, Harrison XA. Amphibian ranaviruses in Europe: important directions for future research. Facets (Ott) 2020. [DOI: 10.1139/facets-2020-0007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are an emerging group of pathogens capable of infecting all cold-blooded vertebrates. In Europe, ranaviruses pose a particularly potent threat to wild amphibian populations. Since the 1980s research on amphibian-infecting ranaviruses in Europe has been growing. The wide distribution of amphibian populations in Europe, the ease with which many are monitored, and the tractable nature of counterpart ex situ experimental systems have provided researchers with a unique opportunity to study many aspects of host–ranavirus interactions in the wild. These characteristics of European amphibian populations will also enable researchers to lead the way as the field of host–ranavirus interactions progresses. In this review, we provide a summary of the current key knowledge regarding amphibian infecting ranaviruses throughout Europe. We then outline important areas of further research and suggest practical ways each could be pursued. We address the study of potential interactions between the amphibian microbiome and ranaviruses, how pollution may exacerbate ranaviral disease either as direct stressors of amphibians or indirect modification of the amphibian microbiome. Finally, we discuss the need for continued surveillance of ranaviral emergence in the face of climate change.
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Affiliation(s)
- Lewis J. Campbell
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53711, USA
| | - Alice H. Pawlik
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - Xavier A. Harrison
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
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24
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Sriwanayos P, Subramaniam K, Stilwell NK, Imnoi K, Popov VL, Kanchanakhan S, Polchana J, Waltzek TB. Phylogenomic characterization of ranaviruses isolated from cultured fish and amphibians in Thailand. Facets (Ott) 2020. [DOI: 10.1139/facets-2020-0043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectothermic vertebrates. In this study, we determined the full genomes of eight ranaviruses isolated from marbled sleeper goby ( Oxyeleotris marmorata), goldfish ( Carassius auratus), guppy ( Poecilia reticulata), tiger frog ( Hoplobatrachus tigerinus), Asian grass frog ( Fejervarya limnocharis), and East Asian bullfrog ( H. rugulosus) cultured or imported into Thailand. These ranaviral isolates induced the same cytopathic effects (i.e., progression of coalescing round plaques) in epithelioma papulosum cyprini (EPC) cell cultures. Transmission electron microscopy of infected EPC cells revealed cytoplasmic viral particles with ultrastructural features typical for ranaviruses. Pairwise genetic comparisons of the complete major capsid protein coding sequences from the Thai ranaviruses displayed the highest identity (99.8%–100%) to a ranavirus (tiger frog virus; TFV) isolated from diseased tiger frogs cultured in China, a slightly lower identity (99.3%–99.4%) to a ranavirus (Wamena virus; WV) isolated from diseased green tree pythons ( Morelia viridis) illegally exported from Papua New Guinea, and a lower identity to 35 other ranaviruses (93.7%–98.6%). Phylogenomic analyses supported the eight Thai ranaviruses, Chinese TFV, and WV as a subclade within a larger frog virus 3 clade. Our findings confirm the spread of TFV among cultured fish and amphibians in Asia and likely in reptiles in Oceania. Biosecurity measures are needed to ensure TFV does not continue to spread throughout Southeast Asia and to other parts of the world via international trade.
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Affiliation(s)
- Preeyanan Sriwanayos
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Natalie K. Stilwell
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Kamonchai Imnoi
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Vsevolod L. Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Somkiat Kanchanakhan
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
- Department of Fisheries, Chonburi Provincial Fishery Office, Chonburi 20000, Thailand
| | - Jaree Polchana
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
| | - Thomas B. Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
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25
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Harrison XA, Price SJ, Hopkins K, Leung WTM, Sergeant C, Garner TWJ. Diversity-Stability Dynamics of the Amphibian Skin Microbiome and Susceptibility to a Lethal Viral Pathogen. Front Microbiol 2019; 10:2883. [PMID: 31956320 PMCID: PMC6951417 DOI: 10.3389/fmicb.2019.02883] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/29/2019] [Indexed: 12/20/2022] Open
Abstract
Variation among animals in their host-associated microbial communities is increasingly recognized as a key determinant of important life history traits including growth, metabolism, and resistance to disease. Quantitative estimates of the factors shaping the stability of host microbiomes over time at the individual level in non-model organisms are scarce. Addressing this gap in our knowledge is important, as variation among individuals in microbiome stability may represent temporal gain or loss of key microbial species and functions linked to host health and/or fitness. Here we use controlled experiments to investigate how both heterogeneity in microbial species richness of the environment and exposure to the emerging pathogen Ranavirus influence the structure and temporal dynamics of the skin microbiome in a vertebrate host, the European common frog (Rana temporaria). Our evidence suggests that altering the bacterial species richness of the environment drives divergent temporal microbiome dynamics of the amphibian skin. Exposure to ranavirus effects changes in skin microbiome structure irrespective of total microbial diversity, but individuals with higher pre-exposure skin microbiome diversity appeared to exhibit higher survival. Higher diversity skin microbiomes also appear less stable over time compared to lower diversity microbiomes, but stability of the 100 most abundant ("core") community members was similar irrespective of microbiome richness. Our study highlights the importance of extrinsic factors in determining the stability of host microbiomes over time, which may in turn have important consequences for the stability of host-microbe interactions and microbiome-fitness correlations.
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Affiliation(s)
- Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,Centre for Ecology and Conservation, University of Exeter, Exeter, United Kingdom
| | - Stephen J Price
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,UCL Genetics Institute, University College London, London, United Kingdom
| | - Kevin Hopkins
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - William T M Leung
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Chris Sergeant
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
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26
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Rosa GM, Bosch J, Martel A, Pasmans F, Rebelo R, Griffiths RA, Garner TWJ. Sex‐biased disease dynamics increase extinction risk by impairing population recovery. Anim Conserv 2019. [DOI: 10.1111/acv.12502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G. M. Rosa
- Durrell Institute of Conservation and Ecology School of Anthropology and Conservation University of Kent CanterburyKent UK
- Institute of Zoology Zoological Society of London Regent's ParkLondon UK
- Centre for Ecology, Evolution and Environmental Changes (CE3C)Faculdade de Ciências da Universidade de LisboaLisboa Portugal
| | - J. Bosch
- Museo Nacional de Ciencias NaturalesCSIC Madrid Spain
| | - A. Martel
- Department of Pathology, Bacteriology and Avian Diseases Faculty of Veterinary Medicine Ghent University Merelbeke Belgium
| | - F. Pasmans
- Department of Pathology, Bacteriology and Avian Diseases Faculty of Veterinary Medicine Ghent University Merelbeke Belgium
| | - R. Rebelo
- Centre for Ecology, Evolution and Environmental Changes (CE3C)Faculdade de Ciências da Universidade de LisboaLisboa Portugal
| | - R. A. Griffiths
- Durrell Institute of Conservation and Ecology School of Anthropology and Conservation University of Kent CanterburyKent UK
| | - T. W. J. Garner
- Institute of Zoology Zoological Society of London Regent's ParkLondon UK
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27
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Vilaça ST, Bienentreu JF, Brunetti CR, Lesbarrères D, Murray DL, Kyle CJ. Frog Virus 3 Genomes Reveal Prevalent Recombination between Ranavirus Lineages and Their Origins in Canada. J Virol 2019; 93:e00765-19. [PMID: 31341053 PMCID: PMC6798099 DOI: 10.1128/jvi.00765-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/10/2019] [Indexed: 12/14/2022] Open
Abstract
Ranaviruses are pathogens associated with the decline of amphibian populations across much of their distribution. In North America, frog virus 3 (FV3) is a widely distributed pathogen with wild populations of amphibians harboring different lineages and putative recombinants between FV3 and common midwife toad virus (CMTV). These recombinants have higher pathogenicity, and CMTV-derived genes associated with virulence are reported in wild strains in Canada. However, while FV3 is linked to amphibian die-offs in North America, CMTVs have been reported only in commercial frog farms in North America. We sequenced complete genomes of 18 FV3 isolates from three amphibian species to characterize genetic diversity of the lineages in Canada and infer possible recombinant regions. The 18 FV3 isolates displayed different signals of recombination, varying from none to interspersed recombination with previously isolated CMTV-like viruses. In general, most recombination breakpoints were located within open reading frames (ORFs), generating new ORFs and proteins that were a mixture between FV3 and CMTV. A combined spatial and temporal phylogeny suggests the presence of the FV3 lineage in Canada is relatively contemporary (<100 years), corroborating the hypothesis that both CMTV- and FV3-like viruses spread to North America when the international commercial amphibian trade started. Our results highlight the importance of pathogen surveillance and viral dynamics using full genomes to more clearly understand the mechanisms of disease origin and spread.IMPORTANCE Amphibian populations are declining worldwide, and these declines have been linked to a number of anthropogenic factors, including disease. Among the pathogens associated with amphibian mortality, ranaviruses have caused massive die-offs across continents. In North America, frog virus 3 (FV3) is a widespread ranavirus that can infect wild and captive amphibians. In this study, we sequenced full FV3 genomes isolated from frogs in Canada. We report widespread recombination between FV3 and common midwife toad virus (CMTV). Phylogenies indicate a recent origin for FV3 in Canada, possibly as a result of international amphibian trade.
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Affiliation(s)
- Sibelle T Vilaça
- Biology Department, Trent University, Peterborough, Ontario, Canada
| | - Joe-Felix Bienentreu
- Genetics and Ecology of Amphibian Research Group (GEARG), Department of Biology, Laurentian University, Sudbury, Ontario, Canada
| | - Craig R Brunetti
- Biology Department, Trent University, Peterborough, Ontario, Canada
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - David Lesbarrères
- Genetics and Ecology of Amphibian Research Group (GEARG), Department of Biology, Laurentian University, Sudbury, Ontario, Canada
| | - Dennis L Murray
- Biology Department, Trent University, Peterborough, Ontario, Canada
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - Christopher J Kyle
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
- Forensic Science Department, Trent University, Peterborough, Ontario, Canada
- Natural Resources DNA Profiling and Forensics Centre, Trent University, Peterborough, Ontario, Canada
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28
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Price SJ, Leung WTM, Owen CJ, Puschendorf R, Sergeant C, Cunningham AA, Balloux F, Garner TWJ, Nichols RA. Effects of historic and projected climate change on the range and impacts of an emerging wildlife disease. GLOBAL CHANGE BIOLOGY 2019; 25:2648-2660. [PMID: 31074105 DOI: 10.1111/gcb.14651] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
The global trend of increasing environmental temperatures is often predicted to result in more severe disease epidemics. However, unambiguous evidence that temperature is a driver of epidemics is largely lacking, because it is demanding to demonstrate its role among the complex interactions between hosts, pathogens, and their shared environment. Here, we apply a three-pronged approach to understand the effects of temperature on ranavirus epidemics in UK common frogs, combining in vitro, in vivo, and field studies. Each approach suggests that higher temperatures drive increasing severity of epidemics. In wild populations, ranavirosis incidents were more frequent and more severe at higher temperatures, and their frequency increased through a period of historic warming in the 1990s. Laboratory experiments using cell culture and whole animal models showed that higher temperature increased ranavirus propagation, disease incidence, and mortality rate. These results, combined with climate projections, predict severe ranavirosis outbreaks will occur over wider areas and an extended season, possibly affecting larval recruitment. Since ranaviruses affect a variety of ectothermic hosts (amphibians, reptiles, and fish), wider ecological damage could occur. Our three complementary lines of evidence present a clear case for direct environmental modulation of these epidemics and suggest management options to protect species from disease.
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Affiliation(s)
- Stephen J Price
- UCL Genetics Institute, London, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - William T M Leung
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | | | - Robert Puschendorf
- School of Biological and Marine Sciences, University of Plymouth, Devon, United Kingdom
| | - Chris Sergeant
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | | | | | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
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29
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Campbell LJ, Garner TWJ, Hopkins K, Griffiths AGF, Harrison XA. Outbreaks of an Emerging Viral Disease Covary With Differences in the Composition of the Skin Microbiome of a Wild United Kingdom Amphibian. Front Microbiol 2019; 10:1245. [PMID: 31281291 PMCID: PMC6597677 DOI: 10.3389/fmicb.2019.01245] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/20/2019] [Indexed: 12/19/2022] Open
Abstract
There is growing appreciation of the important role of commensal microbes in ensuring the normal function and health of their hosts, including determining how hosts respond to pathogens. A range of infectious diseases are threatening amphibians worldwide, and evidence is accumulating that the host-associated bacteria that comprise the microbiome may be key in mediating interactions between amphibian hosts and infectious pathogens. We used 16S rRNA amplicon sequencing to quantify the skin microbial community structure of over 200 individual wild adult European common frogs (Rana temporaria), from ten populations with contrasting history of the lethal disease ranavirosis, caused by emerging viral pathogens belonging to the genus Ranavirus. All populations had similar species richness irrespective of disease history, but populations that have experienced historical outbreaks of ranavirosis have a distinct skin microbiome structure (beta diversity) when compared to sites where no outbreaks of the disease have occurred. At the individual level, neither age, body length, nor sex of the frog could predict the structure of the skin microbiota. Our data potentially support the hypothesis that variation among individuals in skin microbiome structure drive differences in susceptibility to infection and lethal outbreaks of disease. More generally, our results suggest that population-level processes are more important for driving differences in microbiome structure than variation among individuals within populations in key life history traits such as age and body size.
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Affiliation(s)
- Lewis J Campbell
- Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom.,Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Kevin Hopkins
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | | | - Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
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30
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Duffus ALJ, Garner TWJ, Nichols RA, Standridge JP, Earl JE. Modelling Ranavirus Transmission in Populations of Common Frogs ( Rana temporaria) in the United Kingdom. Viruses 2019; 11:v11060556. [PMID: 31208063 PMCID: PMC6630962 DOI: 10.3390/v11060556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
Ranaviruses began emerging in common frogs (Rana temporaria) in the United Kingdom in the late 1980s and early 1990s, causing severe disease and declines in the populations of these animals. Herein, we explored the transmission dynamics of the ranavirus(es) present in common frog populations, in the context of a simple susceptible-infected (SI) model, using parameters derived from the literature. We explored the effects of disease-induced population decline on the dynamics of the ranavirus. We then extended the model to consider the infection dynamics in populations exposed to both ulcerative and hemorrhagic forms of the ranaviral disease. The preliminary investigation indicated the important interactions between the forms. When the ulcerative form was present in a population and the hemorrhagic form was later introduced, the hemorrhagic form of the disease needed to be highly contagious, to persist. We highlighted the areas where further research and experimental evidence is needed and hope that these models would act as a guide for further research into the amphibian disease dynamics.
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Affiliation(s)
- Amanda L J Duffus
- Department of Mathematics and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA.
| | | | - Richard A Nichols
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK.
| | - Joshua P Standridge
- Department of Mathematics and Natural Sciences, Gordon State College, Barnesville, GA 30204, USA.
| | - Julia E Earl
- School of Biological Sciences, Louisiana Tech University, Ruston, LA 71272, USA.
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31
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Kpan TF, Ernst R, Kouassi PK, Rödel M. Prevalence of endoparasitic mites on four West African leaf‐litter frogs depends on habitat humidity. Biotropica 2019. [DOI: 10.1111/btp.12649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Tokouaho Flora Kpan
- Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science Berlin Germany
- Centre Suisse de Recherche Scientifique Abidjan Côte d´Ivoire
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research – BBIB Berlin Germany
| | - Raffael Ernst
- Museum of ZoologySenckenberg Natural History Collections Dresden Dresden Germany
| | - Philippe K. Kouassi
- U.F.R BiosciencesLaboratory of ZoologyUniversity Félix Houphoüet‐Boigny of Cocody Abidjan Côte d´Ivoire
| | - Mark‐Oliver Rödel
- Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science Berlin Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research – BBIB Berlin Germany
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32
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Grant SA, Bienentreu JF, Vilaça ST, Brunetti CR, Lesbarrères D, Murray DL, Kyle CJ. Low intraspecific variation of Frog virus 3 with evidence for novel FV3-like isolates in central and northwestern Canada. DISEASES OF AQUATIC ORGANISMS 2019; 134:1-13. [PMID: 32132268 DOI: 10.3354/dao03354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Frog virus 3 (FV3) and FV3-like ranaviruses can infect a variety of cold-blooded aquatic species and present a primary threat to amphibians across the globe. Previous studies of FV3-like viruses have largely investigated higher-level phylogenetic distinctions of these pathogens via portions of the conserved major capsid protein (MCP), and the putative virulence gene vIF-2α. Few studies, however, have investigated the spatial distribution of FV3 variants at the population level3-data that can be used to further understand the spatial epidemiology of this disease. In this study, we sequenced the MCP and vIF-2α of 127 FV3-positive amphibians sampled from Canadian water bodies in Ontario, northeastern Alberta, and southern Northwest Territories to explore whether intraspecific genetic variation exists within FV3. There was a lack of variation at the 2 markers across these regions, suggesting that there is a lack of FV3 sequence diversity in Canada, which may hint at a single source of infection that has spread. However, an undocumented variant termed Wood Buffalo ranavirus (WBRV) was detected in samples from 3 sites in Alberta and Northwest Territories that clustered within the FV3-like lineage with 99.3% sequence homology for MCP. For vIF-2α, all sequences were the expected truncated variant except for 6 samples in Ontario. These latter sequences were suggestive of recombination with common midwife toad virus (CMTV). The lack of variation suggests that higher-resolution genome analyses will be required to further explore the spatial spread and intraspecific variation of the disease.
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Affiliation(s)
- Samantha A Grant
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario K9J 7B8, Canada
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33
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Bower DS, Brannelly LA, McDonald CA, Webb RJ, Greenspan SE, Vickers M, Gardner MG, Greenlees MJ. A review of the role of parasites in the ecology of reptiles and amphibians. AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Deborah S. Bower
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
- School of Environmental and Rural Science; University of New England; Armidale New South Wales Australia
| | - Laura A. Brannelly
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh Pennsylvania USA
| | - Cait A. McDonald
- Department of Ecology and Evolutionary Biology; Cornell University; Ithaca New York USA
| | - Rebecca J. Webb
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland Australia
| | - Sasha E. Greenspan
- Department of Biological Sciences; University of Alabama; Tuscaloosa Alabama USA
| | - Mathew Vickers
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
| | - Michael G. Gardner
- College of Science and Engineering; Flinders University; Adelaide South Australia Australia
- Evolutionary Biology Unit; South Australian Museum; Adelaide South Australia Australia
| | - Matthew J. Greenlees
- School of Life and Environmental Sciences; University of Sydney; Sydney New South Wales Australia
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34
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Watters JL, Davis DR, Yuri T, Siler CD. Concurrent Infection of Batrachochytrium dendrobatidis and Ranavirus among Native Amphibians from Northeastern Oklahoma, USA. JOURNAL OF AQUATIC ANIMAL HEALTH 2018; 30:291-301. [PMID: 30290015 DOI: 10.1002/aah.10041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 07/22/2018] [Indexed: 06/08/2023]
Abstract
Global amphibian decline continues to be a great concern despite our increased understanding of the causes behind the observed patterns of the decline, such as habitat modification and infectious diseases. Although there is a large body of literature on the topic of amphibian infectious diseases, pathogen prevalence and distribution among entire communities of species in many regions remain poorly understood. In addition to these geographic gaps in our understanding, past work has focused largely on individual pathogens, either Batrachochytrium dendrobatidis (Bd) or ranavirus (RV), rather than dual infection rates among host species. We sampled for prevalence and infection load of both pathogens in 514 amphibians across 16 total sites in northeastern Oklahoma. Amphibians were caught by hand, net, or seine; they were swabbed to screen for Bd; and liver tissue samples were collected to screen for RV. Overall results of quantitative PCR assays showed that 7% of screened individuals were infected with RV only, 37% were infected with Bd only, and 9% were infected with both pathogens simultaneously. We also documented disease presence in several rare amphibian species that are currently being monitored as species of concern due to their small population sizes in Oklahoma. This study synthesizes a growing body of research regarding infectious diseases among amphibian communities in the central United States.
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Affiliation(s)
- Jessa L Watters
- Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, 2401 Chautauqua Avenue, Norman, Oklahoma, 73072-7029, USA
| | - Drew R Davis
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, South Dakota, 57069, USA
| | - Tamaki Yuri
- Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, 2401 Chautauqua Avenue, Norman, Oklahoma, 73072-7029, USA
| | - Cameron D Siler
- Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, 2401 Chautauqua Avenue, Norman, Oklahoma, 73072-7029, USA
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, Oklahoma, 73019, USA
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35
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Campbell LJ, Garner TWJ, Tessa G, Scheele BC, Griffiths AGF, Wilfert L, Harrison XA. An emerging viral pathogen truncates population age structure in a European amphibian and may reduce population viability. PeerJ 2018; 6:e5949. [PMID: 30479902 PMCID: PMC6241393 DOI: 10.7717/peerj.5949] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/17/2018] [Indexed: 11/20/2022] Open
Abstract
Infectious diseases can alter the demography of their host populations, reducing their viability even in the absence of mass mortality. Amphibians are the most threatened group of vertebrates globally, and emerging infectious diseases play a large role in their continued population declines. Viruses belonging to the genus Ranavirus are responsible for one of the deadliest and most widespread of these diseases. To date, no work has used individual level data to investigate how ranaviruses affect population demographic structure. We used skeletochronology and morphology to evaluate the impact of ranaviruses on the age structure of populations of the European common frog (Rana temporaria) in the UK. We compared ecologically similar populations that differed most notably in their historical presence or absence of ranavirosis (the acute syndrome caused by ranavirus infection). Our results suggest that ranavirosis may truncate the age structure of R. temporaria populations. One potential explanation for such a shift might be increased adult mortality and subsequent shifts in the life history of younger age classes that increase reproductive output earlier in life. Additionally, we constructed population projection models which indicated that such increased adult mortality could heighten the vulnerability of frog populations to stochastic environmental challenges.
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Affiliation(s)
- Lewis J Campbell
- Environment and Sustainability Institute, University of Exeter, Penryn, UK.,Institute of Zoology, Zoological Society of London, London, UK.,Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Giulia Tessa
- Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Benjamin C Scheele
- Fenner School of Environment and Society, Australian National University, Canberra, ACT, Australia
| | | | - Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK.,Institute of Evolutionary Ecology and Conservation Genomics, Universität Ulm, Ulm, Germany
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Abstract
Many infectious diseases originating from, or carried by, wildlife affect wildlife conservation and biodiversity, livestock health, or human health. We provide an update on changes in the epidemiology of 25 selected infectious, wildlife-related diseases in Europe (from 2010-16) that had an impact, or may have a future impact, on the health of wildlife, livestock, and humans. These pathogens were selected based on their: 1) identification in recent Europe-wide projects as important surveillance targets, 2) inclusion in European Union legislation as pathogens requiring obligatory surveillance, 3) presence in recent literature on wildlife-related diseases in Europe since 2010, 4) inclusion in key pathogen lists released by the Office International des Epizooties, 5) identification in conference presentations and informal discussions on a group email list by a European network of wildlife disease scientists from the European Wildlife Disease Association, or 6) identification as pathogens with changes in their epidemiology during 2010-16. The wildlife pathogens or diseases included in this review are: avian influenza virus, seal influenza virus, lagoviruses, rabies virus, bat lyssaviruses, filoviruses, canine distemper virus, morbilliviruses in aquatic mammals, bluetongue virus, West Nile virus, hantaviruses, Schmallenberg virus, Crimean-Congo hemorrhagic fever virus, African swine fever virus, amphibian ranavirus, hepatitis E virus, bovine tuberculosis ( Mycobacterium bovis), tularemia ( Francisella tularensis), brucellosis ( Brucella spp.), salmonellosis ( Salmonella spp.), Coxiella burnetii, chytridiomycosis, Echinococcus multilocularis, Leishmania infantum, and chronic wasting disease. Further work is needed to identify all of the key drivers of disease change and emergence, as they appear to be influencing the incidence and spread of these pathogens in Europe. We present a summary of these recent changes during 2010-16 to discuss possible commonalities and drivers of disease change and to identify directions for future work on wildlife-related diseases in Europe. Many of the pathogens are entering Europe from other continents while others are expanding their ranges inside and beyond Europe. Surveillance for these wildlife-related diseases at a continental scale is therefore important for planet-wide assessment, awareness of, and preparedness for the risks they may pose to wildlife, domestic animal, and human health.
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Bufonid herpesvirus 1 (BfHV1) associated dermatitis and mortality in free ranging common toads (Bufo bufo) in Switzerland. Sci Rep 2018; 8:14737. [PMID: 30283010 PMCID: PMC6170376 DOI: 10.1038/s41598-018-32841-0] [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: 01/19/2018] [Accepted: 09/17/2018] [Indexed: 11/22/2022] Open
Abstract
Here we report the discovery and partial characterization of a novel herpesvirus tentatively named Bufonid herpesvirus 1 (BfHV1) from severe dermatitis in free ranging common toads (Bufo bufo) in Switzerland. The disease has been observed in toads every year since 2014, in spring, during the mating season, at different and distant locations. The virus is found in the skin and occasionally in the brain of infected toads. The genome of the virus is at least 158 Kb long and contains at least 152 open reading frames with a minimal length of 270 nt. The genome of BfHV1 contains all the signature genes that are present in alloherpesviruses. Phylogenetic analysis based on the amino acid sequence of the DNA polymerase and terminase proteins positions the novel virus among the members of the genus Batrachovirus, family Alloherpesviridae. This is the first herpesvirus ever characterized in common toads.
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Isidoro-Ayza M, Grear DA, Chambouvet A. Pathology and Case Definition of Severe Perkinsea Infection of Frogs. Vet Pathol 2018; 56:133-142. [PMID: 30236039 DOI: 10.1177/0300985818798132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Severe Perkinsea infection (SPI) is an emerging disease of frogs responsible for mass mortalities of tadpoles across the United States. It is caused by protozoa belonging to the phylum Perkinsozoa that form a distinct group referred to as the Pathogenic Perkinsea Clade of frogs. In this work, we provide detailed description of gross and histologic lesions from 178 naturally infected tadpoles, including 10 species from 22 mortality events and 6 amphibian health monitoring studies from diverse geographic areas. On external examination, we observed abdominal distension (10, 5.6%), cutaneous erythema and petechia (3, 1.7%), subcutaneous edema (3, 1.7%), and areas of white skin discoloration (3, 1.7%). On macroscopic examination of internal organs, we found hepatomegaly (68, 38.2%), splenomegaly (51, 28.7%), nephromegaly (47, 26.4%), ascites (15, 8.4%), segmental irregular thickening and white discoloration of the intestine (8, 4.5%), pancreatomegaly (4, 2.2%), and pancreatic petechia (1, 0.6%). Histologically, over 60% of the liver (148/165, 89.7%), kidney (113/147, 76.9%), spleen (96/97, 99%), and pancreas (46/68, 67.6%) were invaded by myriad intracellular and extracellular Perkinsea hypnospore-like and trophozoite-like organisms. Numerous other tissues were affected to a lesser extent. Mild histiocytic inflammation with fewer lymphocytes or eosinophils was commonly observed in areas of infection that were not obscured by lympho-granulocytic hematopoietic tissue. In light of these observations, we suggest a logical pathogenesis sequence. Finally, we propose a "case definition" for SPI to promote standardized communication of results and prevent misdiagnosis with epidemiological and pathologically overlapping diseases such as ranavirosis.
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Affiliation(s)
- Marcos Isidoro-Ayza
- 1 Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.,2 National Wildlife Health Center-US Geological Survey, Madison, WI, USA
| | - Daniel A Grear
- 3 National Wildlife Health Center-US Geological Survey, Madison, WI, USA
| | - Aurélie Chambouvet
- 4 Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Technopole Brest Iroise, Plouzané, France
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Franklinos LHV, Fernandez JRR, Hydeskov HB, Hopkins KP, Everest DJ, Cunningham AA, Lawson B. Herpesvirus skin disease in free-living common frogs Rana temporaria in Great Britain. DISEASES OF AQUATIC ORGANISMS 2018; 129:239-244. [PMID: 30154283 DOI: 10.3354/dao03246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Infectious disease is a significant driver of global amphibian declines, yet despite this, relatively little is known about the range of pathogens that affect free-living amphibians. Recent detection of the tentatively named Ranid herpesvirus 3 (RHV3), associated with skin disease in free-living common frogs Rana temporaria in Switzerland, helps to address this paucity in knowledge, but the geographic distribution and epidemiology of the pathogen remains unclear. Syndromic surveillance for ranid herpesvirus skin disease was undertaken throughout Great Britain (GB), January 2014 to December 2016. Reports of common frogs with macroscopic skin lesions with a characteristic grey appearance were solicited from members of the public. Post-mortem examination was conducted on one affected frog found dead in 2015 at a site in England. In addition, archived samples from an incident involving common frogs in England in 1997 with similar macroscopic lesions were further investigated. Transmission electron microscopy identified herpes-like virions in skin lesions from both the 1997 and 2015 incidents. RHV3, or RHV3-like virus, was detected in skin lesions from the 2015 case by PCR and sequencing. Our findings indicate that herpesvirus skin disease is endemic in common frogs in GB, with widespread distribution at apparently low prevalence. Further research into the role of host immunity, virus latency and the significance of infection to host survival is required to better understand the epidemiology and impact of cutaneous herpesvirus infections in amphibian populations.
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Affiliation(s)
- L H V Franklinos
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
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40
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Effects of Emerging Infectious Diseases on Amphibians: A Review of Experimental Studies. DIVERSITY-BASEL 2018. [DOI: 10.3390/d10030081] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Numerous factors are contributing to the loss of biodiversity. These include complex effects of multiple abiotic and biotic stressors that may drive population losses. These losses are especially illustrated by amphibians, whose populations are declining worldwide. The causes of amphibian population declines are multifaceted and context-dependent. One major factor affecting amphibian populations is emerging infectious disease. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the fungi Batrachochytrium dendrobatidis and B. salamandrivorans, and ranaviruses. In this review, we assess the effects of these three pathogens on amphibian hosts as found through experimental studies. Such studies offer valuable insights to the causal factors underpinning broad patterns reported through observational studies. We summarize key findings from experimental studies in the laboratory, in mesocosms, and from the field. We also summarize experiments that explore the interactive effects of these pathogens with other contributors of amphibian population declines. Though well-designed experimental studies are critical for understanding the impacts of disease, inconsistencies in experimental methodologies limit our ability to form comparisons and conclusions. Studies of the three pathogens we focus on show that host susceptibility varies with such factors as species, host age, life history stage, population and biotic (e.g., presence of competitors, predators) and abiotic conditions (e.g., temperature, presence of contaminants), as well as the strain and dose of the pathogen, to which hosts are exposed. Our findings suggest the importance of implementing standard protocols and reporting for experimental studies of amphibian disease.
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Standish I, Leis E, Schmitz N, Credico J, Erickson S, Bailey J, Kerby J, Phillips K, Lewis T. Optimizing, validating, and field testing a multiplex qPCR for the detection of amphibian pathogens. DISEASES OF AQUATIC ORGANISMS 2018; 129:1-13. [PMID: 29916388 DOI: 10.3354/dao03230] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Amphibian populations worldwide are facing numerous threats, including the emergence and spread of infectious diseases. In the past 2 decades, Batrachochytrium dendrobatidis (Bd), a parasitic fungus, and a group of viruses comprising the genus Ranavirus have become widespread and resulted in mass mortality events and extirpations worldwide. In 2013, another novel fungus, B. salamandrivorans (Bsal), was attributed to dramatic declines in populations of fire salamander Salamandra salamandra in the Netherlands. Experimental infections demonstrated that Bsal is highly pathogenic to numerous salamander genera. In an effort to prevent the introduction of Bsal to North America, the US Fish and Wildlife Service (USFWS) listed 201 salamander species as injurious wildlife under the Lacey Act. To determine infection status and accurately assess amphibian health, the development of a sensitive and specific diagnostic assay was needed. We describe the optimization and validation of a multiplex quantitative polymerase chain reaction (qPCR) protocol for the simultaneous detection of Bd, Bsal, and frog virus 3-like ranaviruses. A synthetic genome template (gBlock®) containing the target genes from all 3 pathogens served as the positive control and allowed accurate quantification of pathogen genes. The assay was validated in the field using an established non-lethal swabbing technique to survey local amphibian populations throughout a range of habitats. This multiplex qPCR demonstrates high reproducibility, sensitivity, and was capable of detecting both Bd and ranavirus in numerous locations, species, and life stages. Bsal was not detected at any point during these sampling efforts.
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Affiliation(s)
- Isaac Standish
- US Fish and Wildlife Service, Midwest Fisheries Center, La Crosse Fish Health Center, Onalaska, WI 54650, USA
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Talbott K, Wolf TM, Sebastian P, Abraham M, Bueno I, McLaughlin M, Harris T, Thompson R, Pessier AP, Travis D. Factors influencing detection and co-detection of Ranavirus and Batrachochytrium dendrobatidis in Midwestern North American anuran populations. DISEASES OF AQUATIC ORGANISMS 2018; 128:93-103. [PMID: 29733024 DOI: 10.3354/dao03217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Amphibian populations are in decline worldwide as they face a barrage of challenges, including infectious diseases caused by ranaviruses and the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Here we describe seasonal dynamics of Bd and ranavirus detection in free-ranging post-metamorphic wood frogs Lithobates sylvaticus, boreal chorus frogs Pseudacris maculata/triseriata, and gray treefrogs Hyla versicolor/chrysoscelis, sampled over a 3 season gradient in Minnesota (USA) wetlands. We detected Bd in 36% (n = 259) of individuals sampled in 3 wetlands in 2014, and 33% (n = 255) of individuals sampled in 8 wetlands in 2015. We also detected ranavirus in 60% and 18% of individuals sampled in 2014 and 2015, respectively. Ranavirus and Bd were detected concurrently in 26% and 2% of animals sampled in 2014 and 2015, respectively. We report clinical signs and associated infection status of sampled frogs; of the clinical signs observed, skin discoloration was significantly associated with ranavirus infection. Using generalized estimating equations, we found that species, season, wetland, and a species × season interaction term were significant predictors of Bd detection, whereas test year approached significance as a predictor of ranavirus detection. The odds of detecting both pathogens concurrently was significantly influenced by species, season, a species × season interaction term, year, and environmental ammonia. We propose an amphibian health monitoring scheme that couples population size surveys with seasonal molecular surveys of pathogen presence. This information is crucial to monitoring the health of remaining strongholds of healthy amphibian populations, as they face an uncertain future of further anthropogenic change.
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Investigation of multiple mortality events in eastern box turtles (Terrapene carolina carolina). PLoS One 2018; 13:e0195617. [PMID: 29621347 PMCID: PMC5886585 DOI: 10.1371/journal.pone.0195617] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 03/26/2018] [Indexed: 11/19/2022] Open
Abstract
Wildlife mortality investigations are important for conservation, food safety, and public health; but they are infrequently reported for cryptic chelonian species. Eastern box turtles (Terrapene carolina carolina) are declining due to anthropogenic factors and disease, and while mortality investigations have been reported for captive and translocated individuals, few descriptions exist for free-living populations. We report the results of four natural mortality event investigations conducted during routine health surveillance of three Illinois box turtle populations in 2011, 2013, 2014, and 2015. In April 2011, over 50 box turtles were found dead and a polymicrobial necrotizing bacterial infection was diagnosed in five survivors using histopathology and aerobic/anaerobic culture. This represents the first reported occurrence of necrotizing bacterial infection in box turtles. In August 2013, paired histopathology and qPCR ranavirus detection in nine turtles was significantly associated with occupation of moist microhabitats, identification of oral plaques and nasal discharge on physical exam, and increases in the heterophil count and heterophil to lymphocyte ratio (p < 0.05). In July 2014 and 2015, ranavirus outbreaks reoccurred within a 0.2km radius of highly-disturbed habitat containing ephemeral ponds used by amphibians for breeding. qPCR ranavirus detection in five individuals each year was significantly associated with use of moist microhabitats (p < 0.05). Detection of single and co-pathogens (Terrapene herpesvirus 1, adenovirus, and Mycoplasma sp.) was common before, during, and after mortality events, but improved sample size would be necessary to determine the impacts of these pathogens on the occurrence and outcome of mortality events. This study provides novel information about the causes and predictors of natural box turtle mortality events. Continued investigation of health, disease, and death in free-living box turtles will improve baseline knowledge of morbidity and mortality, identify threats to survival, and promote the formation of effective conservation strategies.
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Campbell LJ, Hammond SA, Price SJ, Sharma MD, Garner TWJ, Birol I, Helbing CC, Wilfert L, Griffiths AGF. A novel approach to wildlife transcriptomics provides evidence of disease-mediated differential expression and changes to the microbiome of amphibian populations. Mol Ecol 2018; 27:1413-1427. [PMID: 29420865 DOI: 10.1111/mec.14528] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 01/01/2023]
Abstract
Ranaviruses are responsible for a lethal, emerging infectious disease in amphibians and threaten their populations throughout the world. Despite this, little is known about how amphibian populations respond to ranaviral infection. In the United Kingdom, ranaviruses impact the common frog (Rana temporaria). Extensive public engagement in the study of ranaviruses in the UK has led to the formation of a unique system of field sites containing frog populations of known ranaviral disease history. Within this unique natural field system, we used RNA sequencing (RNA-Seq) to compare the gene expression profiles of R. temporaria populations with a history of ranaviral disease and those without. We have applied a RNA read-filtering protocol that incorporates Bloom filters, previously used in clinical settings, to limit the potential for contamination that comes with the use of RNA-Seq in nonlaboratory systems. We have identified a suite of 407 transcripts that are differentially expressed between populations of different ranaviral disease history. This suite contains genes with functions related to immunity, development, protein transport and olfactory reception among others. A large proportion of potential noncoding RNA transcripts present in our differentially expressed set provide first evidence of a possible role for long noncoding RNA (lncRNA) in amphibian response to viruses. Our read-filtering approach also removed significantly more bacterial reads from libraries generated from positive disease history populations. Subsequent analysis revealed these bacterial read sets to represent distinct communities of bacterial species, which is suggestive of an interaction between ranavirus and the host microbiome in the wild.
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Affiliation(s)
- Lewis J Campbell
- Environment and Sustainability Institute, University of Exeter, Penryn, UK.,Institute of Zoology, Zoological Society of London, London, UK
| | - Stewart A Hammond
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Stephen J Price
- Institute of Zoology, Zoological Society of London, London, UK.,UCL Genetics Institute, University College London, London, UK
| | - Manmohan D Sharma
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | | | - Inanc Birol
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Caren C Helbing
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
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Kwon S, Park J, Choi WJ, Koo KS, Lee JG, Park D. First case of ranavirus-associated mass mortality in a natural population of the Huanren frog (Rana huanrenensis) tadpoles in South Korea. Anim Cells Syst (Seoul) 2017. [DOI: 10.1080/19768354.2017.1376706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Sera Kwon
- Department of Biology, Kangwon National University, Chuncheon, South Korea
| | - Jaejin Park
- Department of Biology, Kangwon National University, Chuncheon, South Korea
| | - Woo-Jin Choi
- Department of Biology, Kangwon National University, Chuncheon, South Korea
| | - Kyo-Soung Koo
- Department of Biology, Kangwon National University, Chuncheon, South Korea
| | - Jin-Gu Lee
- Gyeonggido Agricultural Research and Extension Services, Hwaseong, South Korea
| | - Daesik Park
- Division of Science Education, Kangwon National University, Chuncheon, South Korea
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46
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Price SJ, Wadia A, Wright ON, Leung WTM, Cunningham AA, Lawson B. Screening of a long-term sample set reveals two Ranavirus lineages in British herpetofauna. PLoS One 2017; 12:e0184768. [PMID: 28931029 PMCID: PMC5607163 DOI: 10.1371/journal.pone.0184768] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/30/2017] [Indexed: 11/18/2022] Open
Abstract
Reports of severe disease outbreaks in amphibian communities in mainland Europe due to strains of the common midwife toad virus (CMTV)-like clade of Ranavirus are increasing and have created concern due to their considerable population impacts. In Great Britain, viruses in another clade of Ranavirus-frog virus 3 (FV3)-like-have caused marked declines of common frog (Rana temporaria) populations following likely recent virus introductions. The British public has been reporting mortality incidents to a citizen science project since 1992, with carcasses submitted for post-mortem examination, resulting in a long-term tissue archive spanning 25 years. We screened this archive for ranavirus (458 individuals from 228 incidents) using molecular methods and undertook preliminary genotyping of the ranaviruses detected. In total, ranavirus was detected in 90 individuals from 41 incidents focused in the north and south of England. The majority of detections involved common frogs (90%) but also another anuran, a caudate and a reptile. Most incidents were associated with FV3-like viruses but two, separated by 300 km and 16 years, involved CMTV-like viruses. These British CMTV-like viruses were more closely related to ranaviruses from mainland Europe than to each other and were estimated to have diverged at least 458 years ago. This evidence of a CMTV-like virus in Great Britain in 1995 represents the earliest confirmed case of a CMTV associated with amphibians and raises important questions about the history of ranavirus in Great Britain and the epidemiology of CMTV-like viruses. Despite biases present in the opportunistic sample used, this study also demonstrates the role of citizen science projects in generating resources for research and the value of maintaining long-term wildlife tissue archives.
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Affiliation(s)
- Stephen J. Price
- UCL Genetics Institute, Gower Street, London, United Kingdom
- Institute of Zoology, ZSL, Regents Park, London, United Kingdom
- * E-mail:
| | - Alexandra Wadia
- Institute of Zoology, ZSL, Regents Park, London, United Kingdom
- University of York, York, United Kingdom
| | - Owen N. Wright
- Institute of Zoology, ZSL, Regents Park, London, United Kingdom
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | | | | | - Becki Lawson
- Institute of Zoology, ZSL, Regents Park, London, United Kingdom
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47
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Saucedo B, Hughes J, van Beurden SJ, Suárez NM, Haenen OLM, Voorbergen-Laarman M, Gröne A, Kik MJL. Complete Genome Sequence of Frog virus 3, Isolated from a Strawberry Poison Frog ( Oophaga pumilio) Imported from Nicaragua into the Netherlands. GENOME ANNOUNCEMENTS 2017; 5:e00863-17. [PMID: 28860243 PMCID: PMC5578841 DOI: 10.1128/genomea.00863-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/12/2017] [Indexed: 01/13/2023]
Abstract
Frog virus 3 was isolated from a strawberry poison frog (Oophaga pumilio) imported from Nicaragua via Germany to the Netherlands, and its complete genome sequence was determined. Frog virus 3 isolate Op/2015/Netherlands/UU3150324001 is 107,183 bp long and has a nucleotide similarity of 98.26% to the reference Frog virus 3 isolate.
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Affiliation(s)
| | - Joseph Hughes
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | | | - Nicolás M Suárez
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Olga L M Haenen
- Wageningen Bioveterinary Research of Wageningen UR, Lelystad, the Netherlands
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48
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From fish to frogs and beyond: Impact and host range of emergent ranaviruses. Virology 2017; 511:272-279. [PMID: 28860047 DOI: 10.1016/j.virol.2017.08.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/29/2017] [Accepted: 08/01/2017] [Indexed: 11/21/2022]
Abstract
Ranaviruses are pathogens of ectothermic vertebrates, including amphibians. We reviewed patterns of host range and virulence of ranaviruses in the context of virus genotype and postulate that patterns reflect significant variation in the historical and current host range of three groups of Ranavirus: FV3-like, CMTV-like and ATV-like ranaviruses. Our synthesis supports previous hypotheses about host range and jumps: FV3s are amphibian specialists, while ATVs are predominantly fish specialists that switched once to caudate amphibians. The most recent common ancestor of CMTV-like ranaviruses and FV3-like forms appears to have infected amphibians but CMTV-like ranaviruses may circulate in both amphibian and fish communities independently. While these hypotheses are speculative, we hope that ongoing efforts to describe ranavirus genetics, increased surveillance of host species and targeted experimental assays of susceptibility to infection and/or disease will facilitate better tests of the importance of hypothetical evolutionary drivers of ranavirus virulence and host range.
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49
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Claytor SC, Subramaniam K, Landrau-Giovannetti N, Chinchar VG, Gray MJ, Miller DL, Mavian C, Salemi M, Wisely S, Waltzek TB. Ranavirus phylogenomics: Signatures of recombination and inversions among bullfrog ranaculture isolates. Virology 2017; 511:330-343. [PMID: 28803676 DOI: 10.1016/j.virol.2017.07.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 07/12/2017] [Accepted: 07/24/2017] [Indexed: 01/23/2023]
Abstract
Ranaviruses are emerging pathogens of fish, amphibians, and reptiles that threaten aquatic animal industries and wildlife worldwide. Our objective was to genetically characterize ranaviruses isolated during separate bullfrog Lithobates catesbeianus die-offs that occurred eight years apart on the same North American farm. The earlier outbreak was due to a highly pathogenic strain of common midwife toad virus (CMTV) previously known only from Europe and China. The later outbreak was due to a chimeric ranavirus that displayed a novel genome arrangement and a DNA backbone typical for Frog virus 3 (FV3) strains except for interspersed fragments acquired through recombination with the CMTV isolated earlier. Both bullfrog ranaviruses are more pathogenic than wild-type FV3 suggesting recombination may have resulted in the increased pathogenicity observed in the ranavirus isolated in the later outbreak. Our study underscores the role international trade in farmed bullfrogs may have played in the global dissemination of highly pathogenic ranaviruses.
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Affiliation(s)
- Sieara C Claytor
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, USA
| | | | | | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee, Knoxville, TN, USA
| | - Debra L Miller
- Center for Wildlife Health, University of Tennessee, Knoxville, TN, USA
| | - Carla Mavian
- Department of Pathology, Immunology, and Laboratory Medicine, and Emerging Pathogens Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marco Salemi
- Department of Pathology, Immunology, and Laboratory Medicine, and Emerging Pathogens Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Samantha Wisely
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, USA.
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Origgi FC, Schmidt BR, Lohmann P, Otten P, Akdesir E, Gaschen V, Aguilar-Bultet L, Wahli T, Sattler U, Stoffel MH. Ranid Herpesvirus 3 and Proliferative Dermatitis in Free-Ranging Wild Common Frogs (Rana Temporaria). Vet Pathol 2017; 54:686-694. [PMID: 28494706 DOI: 10.1177/0300985817705176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Amphibian pathogens are of current interest as contributors to the global decline of amphibians. However, compared with chytrid fungi and ranaviruses, herpesviruses have received relatively little attention. Two ranid herpesviruses have been described: namely, Ranid herpesvirus 1 (RHV1) and Ranid herpesvirus 2 (RHV2). This article describes the discovery and partial characterization of a novel virus tentatively named Ranid herpesvirus 3 (RHV3), a candidate member of the genus Batrachovirus in the family Alloherpesviridae. RHV3 infection in wild common frogs (Rana temporaria) was associated with severe multifocal epidermal hyperplasia, dermal edema, a minor inflammatory response, and variable mucous gland degeneration. Intranuclear inclusions were numerous in the affected epidermis together with unique extracellular aggregates of herpesvirus-like particles. The RHV3-associated skin disease has features similar to those of a condition recognized in European frogs for the last 20 years and whose cause has remained elusive. The genome of RHV3 shares most of the features of the Alloherpesviruses. The characterization of this presumptive pathogen may be of value for amphibian conservation and for a better understanding of the biology of Alloherpesviruses.
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Affiliation(s)
- F C Origgi
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland.,2 Institute of Veterinary Bacteriology, DIP, Bern, Switzerland
| | - B R Schmidt
- 3 KARCH, Neuchâtel, Switzerland, and Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | | | - P Otten
- 5 Fasteris SA, Geneva, Switzerland
| | - E Akdesir
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - V Gaschen
- 6 Division of Veterinary Anatomy, University of Bern, Bern, Switzerland
| | | | - T Wahli
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - U Sattler
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - M H Stoffel
- 6 Division of Veterinary Anatomy, University of Bern, Bern, Switzerland
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