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Wei D, Cheng Y, Xiao S, Liao W, Yu Q, Han S, Huang S, Shi J, Xie Z, Li P. Natural occurrences and characterization of Elizabethkingia miricola infection in cultured bullfrogs (Rana catesbeiana). Front Cell Infect Microbiol 2023; 13:1094050. [PMID: 36998635 PMCID: PMC10043317 DOI: 10.3389/fcimb.2023.1094050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
IntroductionThe bacterium Elizabethkingia miricola is a multispecies pathogen associated with meningitis-like disease that has been isolated from several amphibian species, including the bullfrog, but this is the first isolation in Guangxi. In the present study, the dominant bacteria were isolated from the brains of five bullfrogs with meningitis-like disease on a South China farm in Guangxi.MethodsThe NFEM01 isolate was identified by Gram staining; morphological observations; 16S rRNA, rpoB, and mutT-based phylogenetic tree analysis; and physiochemical characterization and was subjected to drug sensitivity and artificial infection testing.Results and discussionAs a result of identification, the NFEM01 strain was found to be E. miricola. An artificial infection experiment revealed that NFEM01 infected bullfrogs and could cause symptoms of typical meningitis-like disease. As a result of the bacterial drug sensitivity test, NFEM01 is highly sensitive to mequindox, rifampicin, enrofloxacin, nitrofural, and oxytetracycline and there was strong resistance to gentamicin, florfenicol, neomycin, penicillin, amoxicillin, doxycycline, and sulfamonomethoxine. This study provides a reference to further study the pathogenesis mechanism of E. miricola-induced bullfrog meningitislike disease and its prevention and treatment.
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Affiliation(s)
- Dongdong Wei
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Beibu Gulf Marine Industrial Research Institute, Guangxi Academy of Marine Sciences, Nanning, China
| | - Yuan Cheng
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Beibu Gulf Marine Industrial Research Institute, Guangxi Academy of Marine Sciences, Nanning, China
| | - Shuangyan Xiao
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Beibu Gulf Marine Industrial Research Institute, Guangxi Academy of Marine Sciences, Nanning, China
| | - Wenyu Liao
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
| | - Qing Yu
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Beibu Gulf Marine Industrial Research Institute, Guangxi Academy of Marine Sciences, Nanning, China
| | - Shuyu Han
- Guangxi Fisheries Technology Extension Station, Nanning, China
| | - Shuaishuai Huang
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
| | - Jingu Shi
- Guangxi Fisheries Technology Extension Station, Nanning, China
| | - Zongsheng Xie
- Guangxi Academy of Fishery Science, Nanning, China
- *Correspondence: Zongsheng Xie, ; Pengfei Li,
| | - Pengfei Li
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Beibu Gulf Marine Industrial Research Institute, Guangxi Academy of Marine Sciences, Nanning, China
- *Correspondence: Zongsheng Xie, ; Pengfei Li,
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Flechas SV, Urbina J, Crawford AJ, Gutiérrez K, Corrales K, Castellanos LA, González MA, Cuervo AM, Catenazzi A. First evidence of ranavirus in native and invasive amphibians in Colombia. DISEASES OF AQUATIC ORGANISMS 2023; 153:51-58. [PMID: 36794841 DOI: 10.3354/dao03717] [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: 06/18/2023]
Abstract
Ranaviruses can cause mass mortality events in amphibians, thereby becoming a threat to populations that are already facing dramatic declines. Ranaviruses affect all life stages and persist in multiple amphibian hosts. The detrimental effects of ranavirus infections to amphibian populations have already been observed in the UK and in North America. In Central and South America, the virus has been reported in several countries, but the presence of the genus Ranavirus (Rv) in Colombia is unknown. To help fill this knowledge gap, we surveyed for Rv in 60 species of frogs (including one invasive species) in Colombia. We also tested for co-infection with Batrachochytrium dendrobatidis (Bd) in a subset of individuals. For Rv, we sampled 274 vouchered liver tissue samples collected between 2014 and 2019 from 41 localities covering lowlands to mountaintop páramo habitat across the country. Using quantitative polymerase chain reaction (qPCR) and end-point PCR, we detected Rv in 14 individuals from 8 localities, representing 6 species, including 5 native frogs of the genera Osornophryne, Pristimantis and Leptodactylus, and the invasive American bullfrog Rana catesbeiana. Bd was detected in 7 of 140 individuals, with 1 co-infection of Rv and Bd in an R. catesbeiana specimen collected in 2018. This constitutes the first report of ranavirus in Colombia and should set off alarms about this new emerging threat to amphibian populations in the country. Our findings provide some preliminary clues about how and when Rv may have spread and contribute to understanding how the pathogen is distributed globally.
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Affiliation(s)
- Sandra V Flechas
- Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, 110321, Colombia
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Auliya M, Altherr S, Nithart C, Hughes A, Bickford D. Numerous uncertainties in the multifaceted global trade in frogs’ legs with the EU as the major consumer. NATURE CONSERVATION 2023. [DOI: 10.3897/natureconservation.51.93868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The commercial trade in frogs and their body parts is global, dynamic and occurs in extremely large volumes (in the thousands of tonnes/yr or billions of frogs/yr). The European Union (EU) remains the single largest importer of frogs’ legs, with most frogs still caught from the wild. Amongst the many drivers of species extinction or population decline (e.g. due to habitat loss, climate change, disease etc.), overexploitation is becoming increasingly more prominent. Due to global declines and extinctions, new attention is being focused on these markets, in part to try to ensure sustainability. While the trade is plagued by daunting realities of data deficiency and uncertainty and the conflicts of commercial interests associated with these data, it is clear is that EU countries are most responsible for the largest portion of the international trade in frogs’ legs of wild species. Over decades of exploitation, the EU imports have contributed to a decline in wild frog populations in an increasing number of supplying countries, such as India and Bangladesh, as well as Indonesia, Turkey and Albania more recently. However, there have been no concerted attempts by the EU and present export countries to ensure sustainability of this trade. Further work is needed to validate species identities, secure data on wild frog populations, establish reasonable monitored harvest/export quotas and disease surveillance and ensure data integrity, quality and security standards for frog farms. Herein, we call upon those countries and their representative governments to assume responsibility for the sustainability of the trade. The EU should take immediate action to channel all imports through a single centralised database and list sensitive species in the Annexes of the EU Wildlife Trade Regulation. Further, listing in CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) can enforce international trade restrictions. More joint efforts are needed to improve regional monitoring schemes before the commercial trade causes irreversible extinctions of populations and species of frogs.
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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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Thumsová B, Price SJ, González-Cascón V, Vörös J, Martínez-Silvestre A, Rosa GM, Machordom A, Bosch J. Climate warming triggers the emergence of native viruses in Iberian amphibians. iScience 2022; 25:105541. [PMID: 36590463 PMCID: PMC9801250 DOI: 10.1016/j.isci.2022.105541] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/19/2022] [Accepted: 11/07/2022] [Indexed: 12/02/2022] Open
Abstract
The number of epizootics in amphibian populations caused by viruses of the genus Ranavirus is increasing worldwide. Yet, causes for pathogen emergence are poorly understood. Here, we confirmed that the Common midwife toad virus (CMTV) and Frog virus 3 (FV3) are responsible for mass mortalities in Iberia since the late 1980s. Our results illustrate the Iberian Peninsula as a diversity hotspot for the highly virulent CMTV. Although this pattern of diversity in Europe is consistent with spread by natural dispersal, the exact origin of the emergence of CMTV remains uncertain. Nevertheless, our data allow hypothesizing that the Iberian Peninsula might harbor the ancestral population of CMTVs that could have spread into the rest of Europe. In addition, we found that climate warming could be triggering the CMTV outbreaks, supporting its endemic status in the Iberian Peninsula.
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Affiliation(s)
- Barbora Thumsová
- Asociación Herpetológica Española (AHE), Madrid, Spain,Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain
| | | | | | - Judit Vörös
- Department of Zoology, Hungarian Natural History Museum, Budapest, Hungary,Laboratory for Molecular Taxonomy, Hungarian Natural History Museum, Budapest, Hungary
| | | | - Gonçalo M. Rosa
- Institute of Zoology, Zoological Society of London, Regents Park, LondonNW1 4RY, UK,Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Annie Machordom
- Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain
| | - Jaime Bosch
- IMIB-Biodiversity Research Institute (University of Oviedo-CSIC-Principality of Asturias), Mieres, Spain,Corresponding author
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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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Humphries JE, Lanctôt CM, Robert J, McCallum HI, Newell DA, Grogan LF. Do immune system changes at metamorphosis predict vulnerability to chytridiomycosis? An update. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 136:104510. [PMID: 35985564 DOI: 10.1016/j.dci.2022.104510] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/20/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Amphibians are among the vertebrate groups suffering great losses of biodiversity due to a variety of causes including diseases, such as chytridiomycosis (caused by the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans). The amphibian metamorphic period has been identified as being particularly vulnerable to chytridiomycosis, with dramatic physiological and immunological reorganisation likely contributing to this vulnerability. Here, we overview the processes behind these changes at metamorphosis and then perform a systematic literature review to capture the breadth of empirical research performed over the last two decades on the metamorphic immune response. We found that few studies focused specifically on the immune response during the peri-metamorphic stages of amphibian development and fewer still on the implications of their findings with respect to chytridiomycosis. We recommend future studies consider components of the immune system that are currently under-represented in the literature on amphibian metamorphosis, particularly pathogen recognition pathways. Although logistically challenging, we suggest varying the timing of exposure to Bd across metamorphosis to examine the relative importance of pathogen evasion, suppression or dysregulation of the immune system. We also suggest elucidating the underlying mechanisms of the increased susceptibility to chytridiomycosis at metamorphosis and the associated implications for population persistence. For species that overlap a distribution where Bd/Bsal are now endemic, we recommend a greater focus on management strategies that consider the important peri-metamorphic period.
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Affiliation(s)
- Josephine E Humphries
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia; Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia.
| | - Chantal M Lanctôt
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Australian Rivers Institute, Griffith University, Southport, Queensland, 4222, Australia
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, 14642, Rochester, NY, United States
| | - Hamish I McCallum
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
| | - David A Newell
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia
| | - Laura F Grogan
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
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The Amphibian Heart. Vet Clin North Am Exot Anim Pract 2022; 25:367-382. [PMID: 35422258 DOI: 10.1016/j.cvex.2022.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Currently, there are more than 8200 amphibian species described, including the orders Anura (frogs and toads), Caudata (salamanders and newts) and Gymnophiona (caecilians). Amphibians have 3 heart chambers: 2 atria and 1 ventricle. Their heart anatomy, histology, and physiology are reviewed. The basic morphology of the heart is similar in all amphibians with some differences due to their lifestyle. Blood flow, blood mixing, and blood oxygenation show variation due to interindividual and interspecific differences. Finally, different diagnostic methods to investigate the amphibian heart are described and reported amphibian heart diseases are summarized, including genetic, congenital, infectious, and neoplastic heart diseases.
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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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Herczeg D, Ujszegi J, Kásler A, Holly D, Hettyey A. Host-multiparasite interactions in amphibians: a review. Parasit Vectors 2021; 14:296. [PMID: 34082796 PMCID: PMC8173923 DOI: 10.1186/s13071-021-04796-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/20/2021] [Indexed: 01/15/2023] Open
Abstract
Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected with more than one parasite species simultaneously. The assessment of such co-infections is of fundamental importance for disease ecology, but relevant studies involving non-domesticated animals have remained scarce. Many amphibians are in decline, and they generally have a highly diverse parasitic fauna. Here we review the literature reporting on field surveys, veterinary case studies, and laboratory experiments on co-infections in amphibians, and we summarize what is known about within-host interactions among parasites, which environmental and intrinsic factors influence the outcomes of these interactions, and what effects co-infections have on hosts. The available literature is piecemeal, and patterns are highly diverse, so that identifying general trends that would fit most host–multiparasite systems in amphibians is difficult. Several examples of additive, antagonistic, neutral, and synergistic effects among different parasites are known, but whether members of some higher taxa usually outcompete and override the effects of others remains unclear. The arrival order of different parasites and the time lag between exposures appear in many cases to fundamentally shape competition and disease progression. The first parasite to arrive can gain a marked reproductive advantage or induce cross-reaction immunity, but by disrupting the skin and associated defences (i.e., skin secretions, skin microbiome) and by immunosuppression, it can also pave the way for subsequent infections. Although there are exceptions, detrimental effects to the host are generally aggravated with increasing numbers of co-infecting parasite species. Finally, because amphibians are ectothermic animals, temperature appears to be the most critical environmental factor that affects co-infections, partly via its influence on amphibian immune function, partly due to its direct effect on the survival and growth of parasites. Besides their importance for our understanding of ecological patterns and processes, detailed knowledge about co-infections is also crucial for the design and implementation of effective wildlife disease management, so that studies concentrating on the identified gaps in our understanding represent rewarding research avenues. ![]()
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Affiliation(s)
- Dávid Herczeg
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Andrea Kásler
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Dóra Holly
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Ecology, Institute for Biology, University of Veterinary Medicine, Rottenbiller utca 50, Budapest, 1077, Hungary
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11
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Ramsay C, Rohr JR. The application of community ecology theory to co-infections in wildlife hosts. Ecology 2021; 102:e03253. [PMID: 33222193 DOI: 10.1002/ecy.3253] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/27/2020] [Accepted: 09/18/2020] [Indexed: 11/11/2022]
Abstract
Priority effect theory, a foundational concept from community ecology, states that the order and timing of species arrival during species assembly can affect species composition. Although this theory has been applied to co-infecting parasite species, it has almost always been with a single time lag between co-infecting parasites. Thus, how the timing of parasite species arrival affects co-infections and disease remains poorly understood. To address this gap in the literature, we exposed postmetamorphic Cuban tree frogs (Osteopilus septentrionalis) to Ranavirus, the fungus Batrachochytrium dendrobatidis (Bd), a nematode Aplectana hamatospicula, or pairs of these parasites either simultaneously or sequentially at a range of time lags and quantified load of the secondary parasite and host growth, survival, and parasite tolerance. Prior exposure to Bd or A. hamatospicula significantly increased viral loads relative to hosts singly infected with Ranavirus, whereas A. hamatospicula loads in hosts were higher when coexposed to Bd than when coexposed to Ranavirus. There was a significant positive relationship between time since Ranavirus infection and Bd load, and prior exposure to A. hamatospicula decreased Bd loads compared to simultaneous co-infection with these parasites. Infections with Bd and Ranavirus either singly or in co-infections decreased host growth and survival. This research reveals that time lags between co-infections can affect parasite loads, in line with priority effects theory. As co-infections in the field are unlikely to be simultaneous, an understanding of when co-infections are impacted by time lags between parasite exposures may play a major role in controlling problematic co-infections.
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Affiliation(s)
- Chloe Ramsay
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Jason R Rohr
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, 46556, USA
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12
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Billig ST, Weber RN, Zimmerman LM, Wilcoxen TE. Effects of elevated corticosterone on humoral innate and antibody-mediated immunity in southern leopard frog (Lithobates sphenocephalus) tadpoles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:756-766. [PMID: 32798287 DOI: 10.1002/jez.2406] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/25/2022]
Abstract
As a free-living larval stage of a vertebrate, tadpoles are good subjects for the study of the development of physiological systems and the study of evolutionarily conserved, context-dependent responses to variable environments. While the basic components of innate and adaptive immune defenses in tadpoles are known, the impact of glucocorticoids on immune defenses in tadpoles is not well-studied. We completed four experiments to assess effects of elevation of corticosterone on humoral innate defenses and antibody-mediated immunity in southern leopard frog tadpoles (Lithobates sphenocephalus). To test humoral innate defense within the tadpoles exposed to short-term and long-term elevation of glucocorticoids, we exposed tadpoles to exogenous corticosterone for different lengths of time in each experiment (0-84 days). We used bacterial killing assays to assess humoral innate immune defense. To test antibody-mediated immune responses, we again exposed tadpoles to exogenous corticosterone, while also exposing them to Aeromonas hydrophila. We used A. hydrophila ELISA comparing IgM and IgY responses among groups. Plasma from corticosterone-dosed tadpoles killed more A. hydrophila than control tadpoles each following a short-term (14 day) and long-term (56 day) exposure to exogenous corticosterone. Conversely, corticosterone-dosed tadpoles had significantly lower IgM and IgY against A. hydrophila after 12 weeks. Our fourth experiment revealed that the lower IgY response is a product of weaker, delayed isotype switching compared with controls. These results show that elevated corticosterone has differential effects on innate and acquired immunity in larval southern leopard frogs, consistent with patterns in more derived vertebrates and in adult frogs.
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Affiliation(s)
- Samuel T Billig
- Department of Biology, Millikin University, Decatur, Illinois
| | - Rachael N Weber
- Department of Biology, Millikin University, Decatur, Illinois
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13
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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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14
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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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15
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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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16
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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: 14] [Impact Index Per Article: 2.8] [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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17
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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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18
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Miaud C, Arnal V, Poulain M, Valentini A, Dejean T. eDNA Increases the Detectability of Ranavirus Infection in an Alpine Amphibian Population. Viruses 2019; 11:E526. [PMID: 31174349 PMCID: PMC6631829 DOI: 10.3390/v11060526] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/23/2019] [Accepted: 06/04/2019] [Indexed: 01/12/2023] Open
Abstract
The early detection and identification of pathogenic microorganisms is essential in order to deploy appropriate mitigation measures. Viruses in the Iridoviridae family, such as those in the Ranavirus genus, can infect amphibian species without resulting in mortality or clinical signs, and they can also infect other hosts than amphibian species. Diagnostic techniques allowing the detection of the pathogen outside the period of host die-off would thus be of particular use. In this study, we tested a method using environmental DNA (eDNA) on a population of common frogs (Rana temporaria) known to be affected by a Ranavirus in the southern Alps in France. In six sampling sessions between June and September (the species' activity period), we collected tissue samples from dead and live frogs (adults and tadpoles), as well as insects (aquatic and terrestrial), sediment, and water. At the beginning of the breeding season in June, one adult was found dead; at the end of July, a mass mortality of tadpoles was observed. The viral DNA was detected in both adults and tadpoles (dead or alive) and in water samples, but it was not detected in insects or sediment. In live frog specimens, the virus was detected from June to September and in water samples from August to September. Dead tadpoles that tested positive for Ranavirus were observed only on one date (at the end of July). Our results indicate that eDNA can be an effective alternative to tissue/specimen sampling and can detect Ranavirus presence outside die-offs. Another advantage is that the collection of water samples can be performed by most field technicians. This study confirms that the use of eDNA can increase the performance and accuracy of wildlife health status monitoring and thus contribute to more effective surveillance programs.
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Affiliation(s)
- Claude Miaud
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Véronique Arnal
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Marie Poulain
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Alice Valentini
- SPYGEN, 17 Rue du Lac Saint-André, 73370 Le Bourget-du-Lac, France.
| | - Tony Dejean
- SPYGEN, 17 Rue du Lac Saint-André, 73370 Le Bourget-du-Lac, France.
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19
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Pathirana NUK, Meegaskumbura M, Rajakaruna RS. Infection sequence alters disease severity-Effects of the sequential exposure of two larval trematodes to Polypedates cruciger tadpoles. Ecol Evol 2019; 9:6220-6230. [PMID: 31236216 PMCID: PMC6580301 DOI: 10.1002/ece3.5180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/25/2018] [Accepted: 01/02/2019] [Indexed: 11/10/2022] Open
Abstract
Multiple pathogens coexist in nature, and hence, host species often encounter several pathogens simultaneously. The sequence in which the host encounters the parasites influences interactions between parasites and host pathology. Here, the effects of infection by two cercaria (larvae of trematodes) types, pleurolophocercous cercaria of Acanthostomum burminis and a furcocercous cercaria, on the tadpoles of common hourglass tree frog (Polypedates cruciger) were examined. Ten days posthatch, tadpoles (Gosner stage 27/28) were used for infection exposures. First, in a single infection each cercaria type was introduced to the tadpoles separately. Second, coinfection of the two cercaria was carried out by alternating the sequences of exposure. For all the experiments, appropriate controls were instituted. Tadpoles of all groups exposed to parasites had lower survival levels compared to controls. Among the four groups exposed, the highest survival was observed in the coinfection when furcocercous was introduced first (82.5%). The lowest survival was observed in the coinfection when the A. burminis cercaria was introduced first (65.0%). In the coinfections, when A. burminis was introduced prior to furcocercous, survival of the tadpoles was reduced by 17.0% compared to the exposures of furcocercous prior to A. burminis. Prior infection with A. burminis induced negative effect on the host with an increased infection severity, while prior infection with furcocercous had reduced infection severity than lone exposures. These results suggest that furcocercous infections can be beneficial for hosts challenged with A. burminis provided that A. burminis exposure occurs second. None of the treatments had an effect on the growth of the tadpoles, but lengthening of developmental period was observed in some exposures. All exposed tadpoles developed malformations which were exclusively axial-kyphosis and scoliosis. However, there was no difference in the number of malformed individuals in the single infection (19.0%-25.0%) compared to coinfection (20.0%-22.5%) or between coinfections. The results suggest that the sequence of parasite exposure affects host-parasite interactions and hence the disease outcomes. Understanding the effects of coinfection on disease outcomes for hosts provides insight into disease dynamics.
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Affiliation(s)
- Nuwandi U. K. Pathirana
- Department of ZoologyUniversity of PeradeniyaPeradeniyaSri Lanka
- Postgraduate Institute of ScienceUniversity of PeradeniyaPeradeniyaSri Lanka
- Freshwater Fish Group and Fish Health Unit, Centre for Sustainable Aquatic Ecosystems, School of Veterinary & Life SciencesMurdoch UniversityPerthAustralia
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory of Forest Ecology & Conservation, College of ForestryGuangxi UniversityNanningChina
- Department of Molecular Biology and Bio‐technologyUniversity of PeradeniyaPeradeniyaSri Lanka
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20
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Casais R, Larrinaga AR, Dalton KP, Domínguez Lapido P, Márquez I, Bécares E, Carter ED, Gray MJ, Miller DL, Balseiro A. Water sports could contribute to the translocation of ranaviruses. Sci Rep 2019; 9:2340. [PMID: 30787411 PMCID: PMC6382805 DOI: 10.1038/s41598-019-39674-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/28/2019] [Indexed: 02/05/2023] Open
Abstract
Ranaviruses have been identified as the cause of explosive disease outbreaks in amphibians worldwide and can be transmitted between hosts both via direct and indirect contact, in which humans might contribute to the translocation of contaminated material. The aim of this study was to evaluate the possible role of water sports in the human translocation of ranavirus, Batrachochytrium dendrobatidis (Bd), and B. salamandrivorans (Bsal). A total of 234 boats were sampled during the spring Spanish Canoe Championship which took place in Pontillón de Castro, a reservoir with a history of ranavirosis, in May 2017. Boats were tested for the presence of ranavirus and Batrachochytrium spp. DNA, using quantitative real-time polymerase chain reaction techniques (qPCR). A total of 22 swabs (22/234, 9.40%) yielded qPCR-positive results for Ranavirus DNA while Bd or Bsal were not detected in any of the samples. We provide the first evidence that human-related water sports could be a source of ranavirus contamination, providing justification for public disinfecting stations in key areas where human traffic from water sports is high.
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Affiliation(s)
- Rosa Casais
- SERIDA, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Asturias, Spain
| | | | - Kevin P Dalton
- Departamento de Bioquímica, Universidad de Oviedo, Oviedo, Spain
| | | | - Isabel Márquez
- SERIDA, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Asturias, Spain
| | - Eloy Bécares
- Facultad de Biología, Universidad de León, Campus de Vegazana, León, Spain
| | - E Davis Carter
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Debra L Miller
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, Tennessee, United States of America
| | - Ana Balseiro
- SERIDA, Servicio Regional de Investigación y Desarrollo Agroalimentario, Gijón, Asturias, Spain.
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21
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Pathogen Risk Analysis for Wild Amphibian Populations Following the First Report of a Ranavirus Outbreak in Farmed American Bullfrogs ( Lithobates catesbeianus) from Northern Mexico. Viruses 2019; 11:v11010026. [PMID: 30609806 PMCID: PMC6356443 DOI: 10.3390/v11010026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/29/2018] [Accepted: 12/24/2018] [Indexed: 01/20/2023] Open
Abstract
Ranaviruses are the second deadliest pathogens for amphibian populations throughout the world. Despite their wide distribution in America, these viruses have never been reported in Mexico, the country with the fifth highest amphibian diversity in the world. This paper is the first to address an outbreak of ranavirus in captive American bullfrogs (Lithobates catesbeianus) from Sinaloa, Mexico. The farm experienced high mortality in an undetermined number of juveniles and sub-adult bullfrogs. Affected animals displayed clinical signs and gross lesions such as lethargy, edema, skin ulcers, and hemorrhages consistent with ranavirus infection. The main microscopic lesions included mild renal tubular necrosis and moderate congestion in several organs. Immunohistochemical analyses revealed scant infected hepatocytes and renal tubular epithelial cells. Phylogenetic analysis of five partial ranavirus genes showed that the causative agent clustered within the Frog virus 3 clade. Risk assessment with the Pandora+ protocol demonstrated a high risk for the pathogen to affect amphibians from neighboring regions (overall Pandora risk score: 0.619). Given the risk of American bullfrogs escaping and spreading the disease to wild amphibians, efforts should focus on implementing effective containment strategies and surveillance programs for ranavirus at facilities undertaking intensive farming of amphibians.
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22
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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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23
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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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24
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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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25
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Effects of Emerging Infectious Diseases on Amphibians: A Review of Experimental Studies. DIVERSITY-BASEL 2018. [DOI: 10.3390/d10030081] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Numerous factors are contributing to the loss of biodiversity. These include complex effects of multiple abiotic and biotic stressors that may drive population losses. These losses are especially illustrated by amphibians, whose populations are declining worldwide. The causes of amphibian population declines are multifaceted and context-dependent. One major factor affecting amphibian populations is emerging infectious disease. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the fungi Batrachochytrium dendrobatidis and B. salamandrivorans, and ranaviruses. In this review, we assess the effects of these three pathogens on amphibian hosts as found through experimental studies. Such studies offer valuable insights to the causal factors underpinning broad patterns reported through observational studies. We summarize key findings from experimental studies in the laboratory, in mesocosms, and from the field. We also summarize experiments that explore the interactive effects of these pathogens with other contributors of amphibian population declines. Though well-designed experimental studies are critical for understanding the impacts of disease, inconsistencies in experimental methodologies limit our ability to form comparisons and conclusions. Studies of the three pathogens we focus on show that host susceptibility varies with such factors as species, host age, life history stage, population and biotic (e.g., presence of competitors, predators) and abiotic conditions (e.g., temperature, presence of contaminants), as well as the strain and dose of the pathogen, to which hosts are exposed. Our findings suggest the importance of implementing standard protocols and reporting for experimental studies of amphibian disease.
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26
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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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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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Affiliation(s)
- Allan P Pessier
- 1 Department of Veterinary Microbiology and Pathology, Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.,2 Amphibian Disease Laboratory, Institute for Conservation Research, San Diego Zoo Global, San Diego, CA, USA
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29
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Huynh TP, Jancovich JK, Tripuraneni L, Heck MC, Langland JO, Jacobs BL. Characterization of a PKR inhibitor from the pathogenic ranavirus, Ambystoma tigrinum virus, using a heterologous vaccinia virus system. Virology 2017; 511:290-299. [PMID: 28919326 PMCID: PMC6192022 DOI: 10.1016/j.virol.2017.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/03/2017] [Accepted: 08/09/2017] [Indexed: 02/07/2023]
Abstract
Ambystoma tigrinum virus (ATV) (family Iridoviridae, genus Ranavirus) was isolated from diseased tiger salamanders (Ambystoma tigrinum stebbinsi) from the San Rafael Valley in southern Arizona, USA in 1996. Genomic sequencing of ATV, as well as other members of the genus, identified an open reading frame that has homology to the eukaryotic translation initiation factor, eIF2α (ATV eIF2α homologue, vIF2αH). Therefore, we asked if the ATV vIF2αH could also inhibit PKR. To test this hypothesis, the ATV vIF2αH was cloned into vaccinia virus (VACV) in place of the well-characterized VACV PKR inhibitor, E3L. Recombinant VACV expressing ATV vIF2αH partially rescued deletion of the VACV E3L gene. Rescue coincided with rapid degradation of PKR in infected cells. These data suggest that the salamander virus, ATV, contains a novel gene that may counteract host defenses, and this gene product may be involved in the presentation of disease caused by this environmentally important pathogen.
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Affiliation(s)
- Trung P Huynh
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - James K Jancovich
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Latha Tripuraneni
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Michael C Heck
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Jeffrey O Langland
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA; Southwest College of Naturopathic Medicine, Tempe, AZ 85282, USA
| | - Bertram L Jacobs
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA.
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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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31
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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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32
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Schoener ER, Hunter S, Howe L. Development of a rapid HRM qPCR for the diagnosis of the four most prevalent Plasmodium lineages in New Zealand. Parasitol Res 2017; 116:1831-1841. [PMID: 28497225 DOI: 10.1007/s00436-017-5452-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 04/20/2017] [Indexed: 11/28/2022]
Abstract
Although wildlife rehabilitation and translocations are important tools in wildlife conservation in New Zealand, disease screening of birds has not been standardized. Additionally, the results of the screening programmes are often difficult to interpret due to missing disease data in resident or translocating avian populations. Molecular methods have become the most widespread method for diagnosing avian malaria (Plasmodium spp.) infections. However, these methods can be time-consuming, expensive and are less specific in diagnosing mixed infections. Thus, this study developed a new real-time PCR (qPCR) method that was able to detect and specifically identify infections of the three most common lineages of avian malaria in New Zealand (Plasmodium (Novyella) sp. SYAT05, Plasmodium elongatum GRW6 and Plasmodium spp. LINN1) as well as a less common, pathogenic Plasmodium relictum GRW4 lineage. The assay was also able to discern combinations of these parasites in the same sample and had a detection limit of five parasites per microlitre. Due to concerns relating to the presence of the potentially highly pathogenic P. relictum GRW4 lineage in avian populations, an additional confirmatory high resolution (HRM) qPCR was developed to distinguish between commonly identified P. elongatum GRW6 from P. relictum GRW4. The new qPCR assays were tested using tissue samples containing Plasmodium schizonts from three naturally infected dead birds resulting in the identified infection of P. elongatum GRW6. Thus, these rapid qPCR assays have shown to be cost-effective and rapid screening tools for the detection of Plasmodium infection in New Zealand native birds.
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Affiliation(s)
- E R Schoener
- Institute of Agriculture and Environment (IAE), Ecology, Massey University, Palmerston North, New Zealand
| | - S Hunter
- Institute of Veterinary, Animal and Biomedical Sciences (IVABS), Massey University, Palmerston North, New Zealand
| | - L Howe
- Institute of Veterinary, Animal and Biomedical Sciences (IVABS), Massey University, Palmerston North, New Zealand.
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33
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Campbell LJ, Head ML, Wilfert L, Griffiths AGF. An ecological role for assortative mating under infection? CONSERV GENET 2017; 18:983-994. [PMID: 32009857 PMCID: PMC6961493 DOI: 10.1007/s10592-017-0951-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 03/01/2017] [Indexed: 11/29/2022]
Abstract
Wildlife diseases are emerging at a higher rate than ever before meaning that understanding their potential impacts is essential, especially for those species and populations that may already be of conservation concern. The link between population genetic structure and the resistance of populations to disease is well understood: high genetic diversity allows populations to better cope with environmental changes, including the outbreak of novel diseases. Perhaps following this common wisdom, numerous empirical and theoretical studies have investigated the link between disease and disassortative mating patterns, which can increase genetic diversity. Few however have looked at the possible link between disease and the establishment of assortative mating patterns. Given that assortative mating can reduce genetic variation within a population thus reducing the adaptive potential and long-term viability of populations, we suggest that this link deserves greater attention, particularly in those species already threatened by a lack of genetic diversity. Here, we summarise the potential broad scale genetic implications of assortative mating patterns and outline how infection by pathogens or parasites might bring them about. We include a review of the empirical literature pertaining to disease-induced assortative mating. We also suggest future directions and methodological improvements that could advance our understanding of how the link between disease and mating patterns influences genetic variation and long-term population viability.
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Affiliation(s)
- L. J. Campbell
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE UK
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, NW1 4RY UK
| | - M. L. Head
- Division of Evolution, Ecology and Genetics, Research School of Biology, Australian National University, Canberra, ACT Australia
| | - L. Wilfert
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE UK
| | - A. G. F. Griffiths
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE UK
- FoAM Kernow, Studio E, Jubilee Warehouse, Commercial Road, Penryn, Cornwall TR10 8FG UK
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Pankovics P, Boros Á, Tóth Z, Phan TG, Delwart E, Reuter G. Genetic characterization of a second novel picornavirus from an amphibian host, smooth newt (Lissotriton vulgaris). Arch Virol 2016; 162:1043-1050. [PMID: 28005212 DOI: 10.1007/s00705-016-3198-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/02/2016] [Indexed: 11/30/2022]
Abstract
In this study, a novel picornavirus was identified in faecal samples from smooth newts (Lissotriton vulgaris). The complete genome of picornavirus strain newt/II-5-Pilis/2014/HUN (KX463670) is 7755 nt long with type-IV IRES and has 39.6% aa sequence identity in the protein P1 to the corresponding protein of bat picornavirus (KJ641686, unassigned) and 42.7% and 53.5% aa sequence identity in the 2C and 3CD protein, respectively, to oscivirus (GU182410, genus Oscivirus). Interestingly, the L-protein of newt/II-5-Pilis/2014/HUN has conserved aa motifs that are similar to those found in phosphatase-1 catalytic (PP1C) subunit binding region (pfam10488) proteins. This second amphibian-origin picornavirus could represent a novel species and could be a founding member of a potential novel picornavirus genus.
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Affiliation(s)
- Péter Pankovics
- Regional Laboratory of Virology, National Reference Laboratory of Gastroenteric Viruses, ÁNTSZ Regional Institute of State Public Health Service, Pecs, Hungary
- Department of Medical Microbiology and Immunology, University of Pécs, Szigeti út 12., Pecs, 7624, Hungary
| | - Ákos Boros
- Regional Laboratory of Virology, National Reference Laboratory of Gastroenteric Viruses, ÁNTSZ Regional Institute of State Public Health Service, Pecs, Hungary
- Department of Medical Microbiology and Immunology, University of Pécs, Szigeti út 12., Pecs, 7624, Hungary
| | - Zoltán Tóth
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tung Gia Phan
- Blood Systems Research Institute, San Francisco, CA, USA
| | - Eric Delwart
- Blood Systems Research Institute, San Francisco, CA, USA
- University of California, San Francisco, CA, USA
| | - Gábor Reuter
- Regional Laboratory of Virology, National Reference Laboratory of Gastroenteric Viruses, ÁNTSZ Regional Institute of State Public Health Service, Pecs, Hungary.
- Department of Medical Microbiology and Immunology, University of Pécs, Szigeti út 12., Pecs, 7624, Hungary.
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35
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Soto-Azat C, Peñafiel-Ricaurte A, Price SJ, Sallaberry-Pincheira N, García MP, Alvarado-Rybak M, Cunningham AA. Xenopus laevis and Emerging Amphibian Pathogens in Chile. ECOHEALTH 2016; 13:775-783. [PMID: 27682604 DOI: 10.1007/s10393-016-1186-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
Amphibians face an extinction crisis with no precedence. Two emerging infectious diseases, ranaviral disease caused by viruses within the genus Ranavirus and chytridiomycosis due to Batrachochytrium dendrobatidis (Bd), have been linked with amphibian mass mortalities and population declines in many regions of the globe. The African clawed frog (Xenopus laevis) has been indicated as a vector for the spread of these pathogens. Since the 1970s, this species has been invasive in central Chile. We collected X. laevis and dead native amphibians in Chile between 2011 and 2013. We conducted post-mortem examinations and molecular tests for Ranavirus and Bd. Eight of 187 individuals (4.3 %) tested positive for Ranavirus: seven X. laevis and a giant Chilean frog (Calyptocephallela gayi). All positive cases were from the original area of X. laevis invasion. Bd was found to be more prevalent (14.4 %) and widespread than Ranavirus, and all X. laevis Bd-positive animals presented low to moderate levels of infection. Sequencing of a partial Ranavirus gene revealed 100 % sequence identity with Frog Virus 3. This is the first report of Ranavirus in Chile, and these preliminary results are consistent with a role for X. laevis as an infection reservoir for both Ranavirus and Bd.
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Affiliation(s)
- Claudio Soto-Azat
- Facultad de Ecología y Recursos Naturales, Centro de Investigación Para la Sustentabilidad, Universidad Andres Bello, Republica 440, Santiago, Chile.
| | - Alexandra Peñafiel-Ricaurte
- Facultad de Ecología y Recursos Naturales, Centro de Investigación Para la Sustentabilidad, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - Stephen J Price
- UCL Genetics Institute, Gower Street, London, WC1E 6BT, UK
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Nicole Sallaberry-Pincheira
- Facultad de Ecología y Recursos Naturales, Centro de Investigación Para la Sustentabilidad, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - María Pía García
- Facultad de Ecología y Recursos Naturales, Centro de Investigación Para la Sustentabilidad, Universidad Andres Bello, Republica 440, Santiago, Chile
- Molecular Virology Laboratory, Fundación Ciencia & Vida, Av. Zañartu 1482, Ñuñoa, Chile
| | - Mario Alvarado-Rybak
- Facultad de Ecología y Recursos Naturales, Centro de Investigación Para la Sustentabilidad, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
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Roy HE, Hesketh H, Purse BV, Eilenberg J, Santini A, Scalera R, Stentiford GD, Adriaens T, Bacela‐Spychalska K, Bass D, Beckmann KM, Bessell P, Bojko J, Booy O, Cardoso AC, Essl F, Groom Q, Harrower C, Kleespies R, Martinou AF, Oers MM, Peeler EJ, Pergl J, Rabitsch W, Roques A, Schaffner F, Schindler S, Schmidt BR, Schönrogge K, Smith J, Solarz W, Stewart A, Stroo A, Tricarico E, Turvey KM, Vannini A, Vilà M, Woodward S, Wynns AA, Dunn AM. Alien Pathogens on the Horizon: Opportunities for Predicting their Threat to Wildlife. Conserv Lett 2016. [DOI: 10.1111/conl.12297] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Helen E. Roy
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Helen Hesketh
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Bethan V. Purse
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Jørgen Eilenberg
- Department of Plant and Environmental SciencesUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Alberto Santini
- Institute for Sustainable Plant Protection ‐ C.N.R Via Madonna del Piano, 10 I‐50019 Sesto Fiorentino Italy
| | - Riccardo Scalera
- IUCN SSC Invasive Species Specialist Group Via Valentino Mazzola 38 T2 B 10 I‐00142 Roma Italy
| | - Grant D. Stentiford
- Centre for EnvironmentFisheries and Aquaculture Science (Cefas) Barrack Road Weymouth Dorset DT4 8UB UK
| | - Tim Adriaens
- Research Institute for Nature and Forest (INBO) Kliniekstraat 25 B‐1070 Brussels Belgium
| | | | - David Bass
- Centre for EnvironmentFisheries and Aquaculture Science (Cefas) Barrack Road Weymouth Dorset DT4 8UB UK
- Department of Life SciencesThe Natural History Museum Cromwell Road London SW7 5BD UK
| | - Katie M. Beckmann
- Wildfowl & Wetlands Trust (WWT) Slimbridge Gloucestershire GL2 7BT UK
| | - Paul Bessell
- The Roslin InstituteUniversity of Edinburgh Easter Bush, Midlothian EH25 9RG Scotland UK
| | - Jamie Bojko
- Centre for EnvironmentFisheries and Aquaculture Science (Cefas) Barrack Road Weymouth Dorset DT4 8UB UK
- School of Biology, Faculty of Biological SciencesUniversity of Leeds Leeds LS2 9JT UK
| | - Olaf Booy
- Animal and Plant Health Agency Sand Hutton York YO41 1LZ UK
- Centre for Wildlife Management, School of BiologyNewcastle University Newcastle‐upon‐Tyne NE1 7RU UK
| | - Ana Cristina Cardoso
- European Commission, DG Joint Research CentreDirectorate D‐ Sustainable Resources 21027 Italy
| | - Franz Essl
- Environment Agency AustriaDepartment of Biodiversity and Nature Conservation Spittelauer Lände 5 1090 Vienna Austria
- Division of Conservation, Vegetation and Landscape EcologyDepartment of Botany and Biodiversity ResearchUniversity Vienna Rennweg 14 1030 Vienna Austria
| | - Quentin Groom
- Botanic Garden MeiseDomein van Bouchout B‐1860 Meise Belgium
| | - Colin Harrower
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Regina Kleespies
- Julius Kühn‐Institute (JKI), Federal Research Centre for Cultivated PlantsInstitute for Biological Control Heinrichstrasse 243 Darmstadt D‐64287 Germany
| | | | - Monique M. Oers
- Laboratory of VirologyWageningen University Droevendaalsesteeg 1 6708 PB Wageningen The Netherlands
| | - Edmund J. Peeler
- Centre for EnvironmentFisheries and Aquaculture Science (Cefas) Barrack Road Weymouth Dorset DT4 8UB UK
| | - Jan Pergl
- Department of Invasion Ecology, Institute of BotanyThe Czech Academy of Sciences CZ‐252 43 Průhonice Czech Republic
| | - Wolfgang Rabitsch
- Environment Agency AustriaDepartment of Biodiversity and Nature Conservation Spittelauer Lände 5 1090 Vienna Austria
| | - Alain Roques
- Institut National de la Recherche Agronomique INRA UR0633, Zoologie Forestière, 45075 Orléans France
| | | | - Stefan Schindler
- Environment Agency AustriaDepartment of Biodiversity and Nature Conservation Spittelauer Lände 5 1090 Vienna Austria
- Division of Conservation, Vegetation and Landscape EcologyDepartment of Botany and Biodiversity ResearchUniversity Vienna Rennweg 14 1030 Vienna Austria
| | - Benedikt R. Schmidt
- Department of Evolutionary Biology and Environmental StudiesUniversity of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland
- KARCH Passage Maximilien‐de‐Meuron 6 2000 Neuchâtel Switzerland
| | - Karsten Schönrogge
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Jonathan Smith
- Animal and Plant Health Agency (APHA)Exotics and Risk Team Area 5A, Nobel House, 17 Smith Square London SW1P 3JR UK
| | - Wojciech Solarz
- Institute of Nature ConservationPolish Academy of Sciences Al. Mickiewicza 33 31–120 Kraków Poland
| | - Alan Stewart
- School of Life SciencesUniversity of Sussex Falmer, Brighton BN1 9QG UK
| | - Arjan Stroo
- Centre for Monitoring of VectorsNetherlands Food and Consumer Product Safety Authority P.O. Box 9102 6700 HC Wageningen The Netherlands
| | - Elena Tricarico
- Università degli Studi di Firenze via Romana 17 I‐50125 Firenze Italy
| | - Katharine M.A. Turvey
- Centre for Ecology & Hydrology, Maclean Building, Benson LaneCrowmarsh Gifford Wallingford Oxfordshire OX10 8BB UK
| | - Andrea Vannini
- DIBAF‐University of Tuscia Via S. Camillo de Lellis 01100 Viterbo Italy
| | - Montserrat Vilà
- Estación Biológica de Doñana (EBD‐CSIC), AvdaAmérico Vespucio s/n, Isla de la Cartuja 41092 Sevilla Spain
| | - Stephen Woodward
- Department of Plant and Soil ScienceUniversity of Aberdeen, Institute of Biological and Environmental Sciences Cruickshank Building, Aberdeen AB24 3UU Scotland UK
| | - Anja Amtoft Wynns
- Department of Plant and Environmental SciencesUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Alison M. Dunn
- School of Biology, Faculty of Biological SciencesUniversity of Leeds Leeds LS2 9JT UK
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Price SJ, Garner TWJ, Cunningham AA, Langton TES, Nichols RA. Reconstructing the emergence of a lethal infectious disease of wildlife supports a key role for spread through translocations by humans. Proc Biol Sci 2016; 283:rspb.2016.0952. [PMID: 27683363 PMCID: PMC5046891 DOI: 10.1098/rspb.2016.0952] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/31/2016] [Indexed: 12/22/2022] Open
Abstract
There have been few reconstructions of wildlife disease emergences, despite their extensive impact on biodiversity and human health. This is in large part attributable to the lack of structured and robust spatio-temporal datasets. We overcame logistical problems of obtaining suitable information by using data from a citizen science project and formulating spatio-temporal models of the spread of a wildlife pathogen (genus Ranavirus, infecting amphibians). We evaluated three main hypotheses for the rapid increase in disease reports in the UK: that outbreaks were being reported more frequently, that climate change had altered the interaction between hosts and a previously widespread pathogen, and that disease was emerging due to spatial spread of a novel pathogen. Our analysis characterized localized spread from nearby ponds, consistent with amphibian dispersal, but also revealed a highly significant trend for elevated rates of additional outbreaks in localities with higher human population density—pointing to human activities in also spreading the virus. Phylogenetic analyses of pathogen genomes support the inference of at least two independent introductions into the UK. Together these results point strongly to humans repeatedly translocating ranaviruses into the UK from other countries and between UK ponds, and therefore suggest potential control measures.
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Affiliation(s)
- Stephen J Price
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK Institute of Zoology, Zoological Society of London, London NW1 4RY, UK School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | | | | | - Tom E S Langton
- Herpetofauna Consultants International, Triton House, Bramfield, Halesworth, Suffolk IP19 9AE, UK
| | - Richard A Nichols
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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Hine PM, Wakefield SJ, Mackereth G, Morrison R. Ultrastructural morphogenesis of a virus associated with lymphocystis-like lesions in parore Girella tricuspidata (Kyphosidae: Perciformes). DISEASES OF AQUATIC ORGANISMS 2016; 121:129-139. [PMID: 27667810 DOI: 10.3354/dao03050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The morphogenesis of large icosahedral viruses associated with lymphocystis-like lesions in the skin of parore Girella tricuspidata is described. The electron-lucent perinuclear viromatrix comprised putative DNA with open capsids at the periphery, very large arrays of smooth endoplasmic reticulum (sER), much of it with a reticulated appearance (rsER) or occurring as rows of vesicles. Lysosomes, degenerating mitochondria and virions in various stages of assembly, and paracrystalline arrays were also present. Long electron-dense inclusions (EDIs) with 15 nm repeating units split terminally and curled to form tubular structures internalising the 15 nm repeating structures. These tubular structures appeared to form the virion capsids. Large parallel arrays of sER sometimes alternated with aligned arrays of crinkled cisternae along which passed a uniformly wide (20 nm) thread-like structure. Strings of small vesicles near open capsids may also have been involved in formation of an inner lipid layer. Granules with a fine fibrillar appearance also occurred in the viromatrix, and from the presence of a halo around mature virions it appeared that the fibrils may form a layer around the capsid. The general features of virogenesis of large icosahedral dsDNA viruses, the large amount of ER, particularly rsER and the EDIs, are features of nucleo-cytoplasmic large DNA viruses, rather than features of 1 genus or family.
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Affiliation(s)
- P M Hine
- National Centre for Disease Investigation, MAF Operations, Ministry of Agriculture and Forestry, PO Box 40-742, Upper Hutt, New Zealand
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Sainsbury AW, Yu-Mei R, Ågren E, Vaughan-Higgins RJ, Mcgill IS, Molenaar F, Peniche G, Foster J. Disease Risk Analysis and Post-Release Health Surveillance for a Reintroduction Programme: the Pool Frog Pelophylax lessonae. Transbound Emerg Dis 2016; 64:1530-1548. [PMID: 27393743 DOI: 10.1111/tbed.12545] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Indexed: 11/30/2022]
Abstract
There are risks from disease in undertaking wild animal reintroduction programmes. Methods of disease risk analysis have been advocated to assess and mitigate these risks, and post-release health and disease surveillance can be used to assess the effectiveness of the disease risk analysis, but results for a reintroduction programme have not to date been recorded. We carried out a disease risk analysis for the reintroduction of pool frogs (Pelophylax lessonae) to England, using information gained from the literature and from diagnostic testing of Swedish pool frogs and native amphibians. Ranavirus and Batrachochytrium dendrobatidis were considered high-risk disease threats for pool frogs at the destination site. Quarantine was used to manage risks from disease due to these two agents at the reintroduction site: the quarantine barrier surrounded the reintroduced pool frogs. Post-release health surveillance was carried out through regular health examinations of amphibians in the field at the reintroduction site and collection and examination of dead amphibians. No significant health or disease problems were detected, but the detection rate of dead amphibians was very low. Methods to detect a higher proportion of dead reintroduced animals and closely related species are required to better assess the effects of reintroduction on health and disease.
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Affiliation(s)
- A W Sainsbury
- Institute of Zoology, Zoological Society of London, London, UK
| | - R Yu-Mei
- Royal Veterinary College, London, UK
| | - E Ågren
- National Veterinary Institute, Uppsala, Sweden
| | | | - I S Mcgill
- Institute of Zoology, Zoological Society of London, London, UK.,Prion Interest Group, Brighton, UK
| | - F Molenaar
- Institute of Zoology, Zoological Society of London, London, UK
| | - G Peniche
- Institute of Zoology, Zoological Society of London, London, UK
| | - J Foster
- Amphibian and Reptile Conservation, Wareham, Dorset, UK
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40
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Johnson AJ, Pessier AP, Jacobson ER. Experimental Transmission and Induction of Ranaviral Disease in Western Ornate Box Turtles (Terrapene ornata ornata) and Red-Eared Sliders (Trachemys scripta elegans). Vet Pathol 2016; 44:285-97. [PMID: 17491069 DOI: 10.1354/vp.44-3-285] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
An experimental transmission study was designed to determine whether a causal relationship exists between a Ranavirus (BSTRV) isolated from a Burmese star tortoise that died and the lesions observed in that tortoise. A pilot study was performed with 3 box turtles ( Terrapene ornata ornata) and 3 red-eared sliders (RESs; Trachemys scripta elegans) to assess their suitability in a larger study. Based on the outcome of this study, RESs were selected, and 2 groups of 4 RESs received either an oral (PO) or intramuscular (IM) inoculum containing105 50% Tissue Culture Infecting Dose (TCID50) of a BSTRV-infected cell lysate. One turtle each was mock inoculated PO or IM with the same volume of uninfected cell lysate. Three of four IM-inoculated RESs developed clinical signs (nasal and ocular discharge [3 of 3], oral plaques [1 of 3], conjunctivitis and hyphema [1 of 3] and extreme lethargy [3 of 3]). A Ranavirus was isolated from kidney homogenates of 3 euthanatized turtles; DNA sequences of a portion of the major capsid protein gene were amplified by polymerase chain reaction. Consistent histologic lesions were observed only in IM-inoculated turtles and included fibrinoid vasculitis centered on splenic ellipsoids, multifocal hepatic necrosis, and multicentric fibrin thrombi in a variety of locations, including hepatic sinusoids, glomerular capillary loops, and pulmonary capillaries. Virions compatible with Ranavirus were observed within necrotic cells of the spleen of 1 IM-inoculated turtle using transmission electron microscopy. This study fulfills Koch's postulates, confirming a causal relationship between BSTRV and the clinical and histologic changes in chelonians infected with this virus.
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Affiliation(s)
- A J Johnson
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
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41
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Forbes MR, Mcruer DL, Rutherford PL. Prevalence of Aeromonas hydrophila in relation to timing and duration of breeding in three species of ranid frogs. ECOSCIENCE 2016. [DOI: 10.1080/11956860.2004.11682834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Mark R. Forbes
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
| | - David L. Mcruer
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
| | - Pamela L. Rutherford
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
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Abstract
Pathogenic fungi and viruses cause mortality outbreaks in wild amphibians worldwide. In the summer of 2012, dead tadpoles and adults of the European common frog Rana temporaria were reported in alpine lakes in the southwestern Alps (Mercantour National Park, France). A preliminary investigation using molecular diagnostic techniques identified a Ranavirus as the potential pathogenic agent. Three mortality events were recorded in the park, and samples were collected. The amphibian chytrid fungus Batrachochytrium dendrobatidis was not detected in any of the dead adult and juvenile frogs sampled (n=16) whereas all specimens were positive for a Ranavirus. The genome sequence of this Ranavirus was identical to previously published sequences of the common midwife toad virus (CMTV), a Ranavirus that has been associated with amphibian mortalities throughout Europe. We cultured virus from the organs of the dead common frogs and infecting adult male common frogs collected in another alpine region where no frog mortality had been observed. The experimentally infected frogs suffered 100% mortality (n=10). The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France. We describe the lesions observed and summarize amphibian populations affected by Ranaviruses in Europe. In addition, we discuss the ecologic specificities of mountain amphibians that may contribute to increasing their risk of exposure to and transmission of Ranaviruses.
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Lawson B, Petrovan SO, Cunningham AA. Citizen Science and Wildlife Disease Surveillance. ECOHEALTH 2015; 12:693-702. [PMID: 26318592 DOI: 10.1007/s10393-015-1054-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 07/20/2015] [Accepted: 08/01/2015] [Indexed: 06/04/2023]
Abstract
Achieving effective wildlife disease surveillance is challenging. The incorporation of citizen science (CS) in wildlife health surveillance can be beneficial, particularly where resources are limited and cost-effectiveness is paramount. Reports of wildlife morbidity and mortality from the public facilitate large-scale surveillance, both in time and space, which would otherwise be financially infeasible, and raise awareness of incidents occurring on privately owned land. CS wildlife disease surveillance schemes benefit scientists, the participating public and wildlife alike. CS has been employed for targeted, scanning and syndromic surveillance of wildlife disease. Whilst opportunistic surveillance is most common, systematic observations enable the standardisation of observer effort and, combined with wildlife population monitoring schemes, can allow evaluation of disease impacts at the population level. Near-universal access to digital media has revolutionised reporting modalities and facilitated rapid and economical means of sharing feedback with participants. Here we review CS schemes for wildlife disease surveillance and highlight their scope, benefits, logistical considerations, financial implications and potential limitations. The need to adopt a collaborative and multidisciplinary approach to wildlife health surveillance is increasingly recognised and the general public can make a significant contribution through CS.
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Affiliation(s)
- Becki Lawson
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK.
| | | | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
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Price SJ, Garner TWJ, Balloux F, Ruis C, Paszkiewicz KH, Moore K, Griffiths AGF. A de novo Assembly of the Common Frog (Rana temporaria) Transcriptome and Comparison of Transcription Following Exposure to Ranavirus and Batrachochytrium dendrobatidis. PLoS One 2015; 10:e0130500. [PMID: 26111016 PMCID: PMC4481470 DOI: 10.1371/journal.pone.0130500] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/19/2015] [Indexed: 12/22/2022] Open
Abstract
Amphibians are experiencing global declines and extinctions, with infectious diseases representing a major factor. In this study we examined the transcriptional response of metamorphic hosts (common frog, Rana temporaria) to the two most important amphibian pathogens: Batrachochytrium dendrobatidis (Bd) and Ranavirus. We found strong up-regulation of a gene involved in the adaptive immune response (AP4S1) at four days post-exposure to both pathogens. We detected a significant transcriptional response to Bd, covering the immune response (innate and adaptive immunity, complement activation, and general inflammatory responses), but relatively little transcriptional response to Ranavirus. This may reflect the higher mortality rates found in wild common frogs infected with Ranavirus as opposed to Bd. These data provide a valuable genomic resource for the amphibians, contribute insight into gene expression changes after pathogen exposure, and suggest potential candidate genes for future host-pathogen research.
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Affiliation(s)
- Stephen J. Price
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
- * E-mail: (SJP); (AGFG)
| | | | - Francois Balloux
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
| | - Chris Ruis
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
| | - Konrad H. Paszkiewicz
- Wellcome Trust Biomedical Informatics Hub, Biosciences, Geoffrey Pope Building, University of Exeter, Streatham Campus, Exeter, United Kingdom
| | - Karen Moore
- Wellcome Trust Biomedical Informatics Hub, Biosciences, Geoffrey Pope Building, University of Exeter, Streatham Campus, Exeter, United Kingdom
| | - Amber G. F. Griffiths
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
- * E-mail: (SJP); (AGFG)
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Effects of acute restraint stress, prolonged captivity stress and transdermal corticosterone application on immunocompetence and plasma levels of corticosterone on the cururu Toad (Rhinella icterica). PLoS One 2015; 10:e0121005. [PMID: 25831055 PMCID: PMC4382218 DOI: 10.1371/journal.pone.0121005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/09/2015] [Indexed: 11/19/2022] Open
Abstract
Glucocorticoid steroids modulate immunocompetence in complex ways with both immunoenhancing and immunosuppressive effects in vertebrates exposed to different stressors. Such bimodal effects have been associated with variation in duration and intensity of the stress response. Given that natural populations have been exposed to a multitude of stressors, a better understanding of the functional association between duration and intensity of the stress response, the resulting changes in glucocorticoid plasma levels and their impact on different aspects of immunocompetence emerges as a cornerstone for vertebrate conservation strategies. We investigated the effects of a restraint challenge (with and without movement restriction), long-term captivity, and transdermal corticosterone application on plasma levels of corticosterone (hereinafter referred to as CORT) and different parameters of innate immunocompetence in the male cururu toads (Rhinella icterica). We show that for R. icterica restraint for 24h proved to be a stressful condition, increasing CORT by 3-fold without consistent immunological changes. However, the application of a more intense stressor (restraint with movement restriction), for the same period, potentiated this response resulting in a 9-fold increase in CORT, associated with increase Neutrophil/Lymphocyte ratio (N:L) and a lower bacterial killing ability (BKA). Transdermal application of corticosterone efficiently mimics repeated acute stress response events, without changing the immune parameters even after 13 days of treatment. Interestingly, long-term captivity did not mitigate the stress response, since the toads maintained 3-fold increased CORT even after 3 months under these conditions. Moreover, long-term captivity in the same condition increased total leukocyte count (TLC) and generated an even greater decrease in BKA, suggesting that consequences of the stress response can be aggravated by time in captivity.
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Pathology of a Bohle-like Virus Infection in Two Australian Frog Species (Litoria splendida and Litoria caerulea). J Comp Pathol 2015; 152:248-59. [DOI: 10.1016/j.jcpa.2014.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/06/2014] [Accepted: 12/16/2014] [Indexed: 11/22/2022]
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47
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Duffus ALJ, Nichols RA, Garner TWJ. Experimental evidence in support of single host maintenance of a multihost pathogen. Ecosphere 2014. [DOI: 10.1890/es14-00074.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Collapse of amphibian communities due to an introduced Ranavirus. Curr Biol 2014; 24:2586-91. [PMID: 25438946 DOI: 10.1016/j.cub.2014.09.028] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/13/2014] [Accepted: 09/09/2014] [Indexed: 11/22/2022]
Abstract
The emergence of infectious diseases with a broad host range can have a dramatic impact on entire communities and has become one of the main threats to biodiversity. Here, we report the simultaneous exploitation of entire communities of potential hosts with associated severe declines following invasion by a novel viral pathogen. We found two phylogenetically related, highly virulent viruses (genus Ranavirus, family Iridoviridae) causing mass mortality in multiple, diverse amphibian hosts in northern Spain, as well as a third, relatively avirulent virus. We document host declines in multiple species at multiple sites in the region. Our work reveals a group of pathogens that seem to have preexisting capacity to infect and evade immunity in multiple diverse and novel hosts, and that are exerting massive impacts on host communities. This report provides an exceptional record of host population trends being tracked in real time following emergence of a wildlife disease and a striking example of a novel, generalist pathogen repeatedly crossing the species barrier with catastrophic consequences at the level of host communities.
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Cheng K, Jones MEB, Jancovich JK, Burchell J, Schrenzel MD, Reavill DR, Imai DM, Urban A, Kirkendall M, Woods LW, Chinchar VG, Pessier AP. Isolation of a Bohle-like iridovirus from boreal toads housed within a cosmopolitan aquarium collection. DISEASES OF AQUATIC ORGANISMS 2014; 111:139-152. [PMID: 25266901 DOI: 10.3354/dao02770] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A captive 'survival assurance' population of 56 endangered boreal toads Anaxyrus boreas boreas, housed within a cosmopolitan collection of amphibians originating from Southeast Asia and other locations, experienced high mortality (91%) in April to July 2010. Histological examination demonstrated lesions consistent with ranaviral disease, including multicentric necrosis of skin, kidney, liver, spleen, and hematopoietic tissue, vasculitis, and myriad basophilic intracytoplasmic inclusion bodies. Initial confirmation of ranavirus infection was made by Taqman real-time PCR analysis of a portion of the major capsid protein (MCP) gene and detection of iridovirus-like particles by transmission electron microscopy. Preliminary DNA sequence analysis of the MCP, DNA polymerase, and neurofilament protein (NFP) genes demonstrated highest identity with Bohle iridovirus (BIV). A virus, tentatively designated zoo ranavirus (ZRV), was subsequently isolated, and viral protein profiles, restriction fragment length polymorphism analysis, and next generation DNA sequencing were performed. Comparison of a concatenated set of 4 ZRV genes, for which BIV sequence data are available, with sequence data from representative ranaviruses confirmed that ZRV was most similar to BIV. This is the first report of a BIV-like agent outside of Australia. However, it is not clear whether ZRV is a novel North American variant of BIV or whether it was acquired by exposure to amphibians co-inhabiting the same facility and originating from different geographic locations. Lastly, several surviving toads remained PCR-positive 10 wk after the conclusion of the outbreak. This finding has implications for the management of amphibians destined for use in reintroduction programs, as their release may inadvertently lead to viral dissemination.
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Affiliation(s)
- Kwang Cheng
- Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Yu X, Zheng R, Zhang J, Shen B, Dong B. Genetic polymorphism of major histocompatibility complex class IIB alleles and pathogen resistance in the giant spiny frog Quasipaa spinosa. INFECTION GENETICS AND EVOLUTION 2014; 28:175-82. [PMID: 25269786 DOI: 10.1016/j.meegid.2014.09.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/28/2014] [Accepted: 09/22/2014] [Indexed: 12/31/2022]
Abstract
Major histocompatibility complex (MHC) genes are candidates for determining disease susceptibility due to their pivotal role in both innate and adaptive immune responses. Accordingly, the association between the genetic variation of MHC genes and the pathogen resistance has been investigated in numerous vertebrates. To date, however, little is reported in amphibians. In this study, we investigate the genetic variation at the MHC class IIB gene in the giant spiny frog Quasipaa spinosa, which has high commercial value in China. The full length of MHC class IIB cDNA was cloned from Q. spinosa by homology cloning and rapid amplification of cDNA end-polymerase chain reaction (RACE-PCR). Two MHC class IIB loci were identified in Q. spinosa. We also developed PCR primers for a portion of the second exon of the MHC class IIB gene. A total of 26 MHC class IIB alleles were identified. The dN rate was significantly higher than the dS rate in the putative peptide-binding region, thereby proving the positive selection hypothesis. In addition, individuals intraperitoneally injected with Aeromonas hydrophila were used to study the association between MHC class IIB alleles and pathogen resistance/susceptibility, to explore the specific alleles in balancing selection. Eighty frogs were used after exposure to A. hydrophila infection. Nine alleles were used to study the association between the alleles and disease resistance. Two alleles, namely, Pasa-DAB(∗)1301 and Pasa-DAB(∗)0901, were significantly associated with resistance against A. hydrophila. This study provides valuable information on the structure of the MHC class IIB gene and confirms the association between MHC class IIB gene alleles and disease resistance to bacterial infection in Q. spinosa. Moreover, pathogen resistance-related MHC markers can be used for the selective breeding of the giant spiny frog.
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Affiliation(s)
- Xiaoyun Yu
- Institute of Ecology, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Rongquan Zheng
- Institute of Ecology, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
| | - Jiayong Zhang
- Institute of Ecology, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Bing Shen
- Institute of Ecology, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Baojuan Dong
- Institute of Ecology, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
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