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Cavasos K, Poudyal NC, Brunner JL, Warwick AR, Jones J, Moherman N, George M, Willard JD, Brinks ZT, Gray MJ. Attitudes and Behavioral Intentions of Pet Amphibian Owners About Biosecurity Practices. ECOHEALTH 2023; 20:194-207. [PMID: 37486511 DOI: 10.1007/s10393-023-01645-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 07/25/2023]
Abstract
Global trade has been linked with the emergence of novel pathogens and declines in amphibian populations worldwide. The potential for pathogen transmission within and between collections of captive amphibians and spillover to wild populations makes it important to understand the motivations, knowledge, attitudes and behaviors of pet amphibian owners. We surveyed US pet amphibian owners to understand their characteristics and evaluated whether and how they were associated with behavioral intentions to adopt biosecurity practices. We found that the majority of pet amphibian owners are aware of the threat of emerging pathogens, concerned about potential spillover of pathogens from captive to wild populations and willing to adopt biosecurity practices to mitigate pathogen threats. Intentions to adopt such practices were driven more by psychosocial constructs such as attitudes, perceptions and beliefs than demographic characteristics. Pet amphibian owners also expressed a strong interest in acquiring, and willingness to pay a price premium for, certified disease-free animals. These findings advance our understanding of the characteristics, motivations and behaviors of pet owners, a key stakeholder in global amphibian trade, which could help to inform new policies and outreach strategies to engage them in mitigating pathogen threats. Moreover, our results imply the economic viability of a market-based program to promote pathogen-free, sustainable trade of amphibians.
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Affiliation(s)
- Kevin Cavasos
- School of Natural Resources, University of Tennessee, Knoxville, TN, 37996, USA
| | - Neelam C Poudyal
- School of Natural Resources, University of Tennessee, Knoxville, TN, 37996, USA.
| | - Jesse L Brunner
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Alexa R Warwick
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, 48824, USA
| | - Joshua Jones
- Pet Advocacy Network, Alexandria, VA, 22314, USA
| | | | | | | | | | - Matthew J Gray
- School of Natural Resources, University of Tennessee, Knoxville, TN, 37996, USA
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Fu M, Waldman B. Novel chytrid pathogen variants and the global amphibian pet trade. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13938. [PMID: 35561039 DOI: 10.1111/cobi.13938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/25/2022] [Indexed: 06/15/2023]
Abstract
Global wildlife trade spreads emerging infectious diseases that threaten biodiversity. The amphibian chytrid pathogen Batrachochytrium dendrobatidis (Bd) has caused population declines and species extinctions worldwide except in Asia. Fire-bellied toads (Bombina orientalis), exported in large numbers from Asia, are tolerant of Bd and carry hypervirulent ancestral chytrid BdAsia-1 variants. We assayed the virulence of a new isolate of BdAsia-1 on the model Australasian frog host Litoria caerulea. Infected individuals (n = 15) all showed rapid disease progression culminating in death, whereas sham-inoculated individuals (n = 10) presented no clinical signs of disease and all survived (log rank test, χ2 = 15.6, df = 1, p < 0.0001). The virulence of the new isolate of BdAsia-1 is comparable to the one we assayed previously (χ2 = 0.0, df = 1, p = 0.91). Internationally traded wildlife, even when they appear healthy, can carry hypervirulent variants of pathogens. Once new pathogen variants escape into the environment, native species that have had no opportunity to evolve resistance to them may perish. Our study suggests that hypervirulent pathogens are being spread by the international pet trade. Notifiable wildlife diseases attributable to locally endemic pathogens often fail to generate conservation concern so are rarely subject to border surveillance or import controls. Because of the danger novel variants pose, national border control agencies need to implement disease screening and quarantine protocols to ensure the safety of their endemic fauna.
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Affiliation(s)
- Minjie Fu
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Bruce Waldman
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma, USA
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Pienaar EF, Episcopio-Sturgeon DJ, Steele ZT. Investigating public support for biosecurity measures to mitigate pathogen transmission through the herpetological trade. PLoS One 2022; 17:e0262719. [PMID: 35061831 PMCID: PMC8782347 DOI: 10.1371/journal.pone.0262719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 01/03/2022] [Indexed: 11/19/2022] Open
Abstract
The expanding global trade in herpetofauna has contributed to new infectious disease dynamics and pathways that allow for the rapid spread of pathogens geographically. Improved biosecurity is needed to mitigate adverse biodiversity, economic and human health impacts associated with pathogen transmission through the herpetological trade. However, general lack of knowledge of the pathogen transmission risks associated with the global trade in herpetofauna and public opposition to biosecurity measures are critical obstacles to successfully preventing pathogen transmission. In 2019 we administered a survey to 2,007 members of the public in the United States of America to ascertain their support for interventions to prevent the spread of Batrachochytrium dendrobatidis (Bd), Batrachochytrium salamandrivorans (Bsal), ranaviruses, and Salmonella through the herpetological trade. We presented survey respondents with different potential hazards associated with pathogen transmission through this trade, namely ecological, economic, and human health impacts. We used structural equation models to determine how these different hazards and respondents’ characteristics influenced respondents’ support for quarantine and veterinary observation of herpetofauna imported into the United States, mandatory tests for diseases of concern, and best practices to reduce stress and improve the care of live herpetofauna during transport to the United States. Respondents’ values and their perceived susceptibility and sensitivity to different hazards associated with pathogen transmission were key determinants of their support for biosecurity. Respondents with strong biospheric and altruistic values demonstrated sensitivity to ecological and human health impacts associated with pathogen transmission, whereas respondents with strong egoistic values demonstrated sensitivity to economic impacts. Respondents had limited knowledge of Bd, Bsal or ranaviruses, the size of the herpetological trade, or how this trade may contribute to pathogen transmission. Improved outreach and education on pathogen transmission through the herpetological trade is required, but it is important that messages are tailored to people with different values to elicit their support for biosecurity.
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Affiliation(s)
- Elizabeth F. Pienaar
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, United States of America
- Mammal Research Institute, University of Pretoria, Pretoria, Gauteng, South Africa
- * E-mail:
| | - Diane J. Episcopio-Sturgeon
- School of Natural Resources and Environment, University of Florida, Gainesville, Florida, United States of America
| | - Zachary T. Steele
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, United States of America
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Box EK, Cleveland CA, Subramaniam K, Waltzek TB, Yabsley MJ. Molecular Confirmation of Ranavirus Infection in Amphibians From Chad, Africa. Front Vet Sci 2021; 8:733939. [PMID: 34604370 PMCID: PMC8481899 DOI: 10.3389/fvets.2021.733939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/16/2021] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are DNA viruses (Family Iridoviridae; Subfamily Alphairidovirinae) and ranaviral disease is considered an emerging infectious disease of ectothermic vertebrates. Ranavirus infection can have varying pathological effects on infected amphibians, reptiles, and fish, most notably causing significant mortality events and population declines. Despite having a broad global range with reports from six continents, only a single incidental finding in Xenopus longipes from mainland Africa (Cameroon) is known and lacks molecular confirmation. Thus, there is a considerable knowledge gap concerning ranaviruses in Africa. We opportunistically obtained tissue samples from 160 amphibians representing five genera (Hoplobatrachus, Hylarana, Ptychadena, Pyxicephalus, and Xenopus) and two turtles (Pelomedusa sp.) from Chad, Africa. Samples were tested for ranavirus infection using a conventional PCR assay targeting the major capsid protein (MCP). A total of 25/160 (16%) frogs tested positive including 15/87 (17%) Hoplobatrachus occipitalis, 10/58 (17%) Ptychadena spp., 0/3 Pyxicephalus spp., 0/9 Xenopus spp., and 0/3 Hylarana spp. One of two turtles tested positive. Partial MCP gene sequences indicated all samples were >98% similar to several frog virus 3 (FV3)-like sequences. Additional gene targets (DNA polymerase [DNApol], ribonucleotide reductase alpha [RNR- α], ribonucleotide reductase beta subunit [RNR- β]) were sequenced to provide further detailed classification of the virus. Sequences of individual gene targets indicate that the ranavirus detected in frogs in Chad is most similar to tiger frog virus (TFV), a FV3-like virus previously isolated from diseased amphibians cultured in China and Thailand. Full genome sequencing of one sample indicates that the Chad frog virus (CFV) is a well-supported sister group to the TFVs previously determined from Asia. This work represents the first molecular confirmation of ranaviruses from Africa and is a first step in comparing ranavirus phylogeography on a local and global scale.
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Affiliation(s)
- Erin K Box
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Christopher A Cleveland
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.,Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States
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Hughes AC, Marshall BM, Strine C. Gaps in global wildlife trade monitoring leave amphibians vulnerable. eLife 2021; 10:70086. [PMID: 34382939 PMCID: PMC8425949 DOI: 10.7554/elife.70086] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/11/2021] [Indexed: 11/21/2022] Open
Abstract
As the biodiversity crisis continues, we must redouble efforts to understand and curb pressures pushing species closer to extinction. One major driver is the unsustainable trade of wildlife. Trade in internationally regulated species gains the most research attention, but this only accounts for a minority of traded species and we risk failing to appreciate the scale and impacts of unregulated legal trade. Despite being legal, trade puts pressure on wild species via direct collection, introduced pathogens, and invasive species. Smaller species-rich vertebrates, such as reptiles, fish, and amphibians, may be particularly vulnerable to trading because of gaps in regulations, small distributions, and demand of novel species. Here, we combine data from five sources: online web searches in six languages, Convention on International Trade in Endangered Species (CITES) trade database, Law Enforcement Management Information System (LEMIS) trade inventory, IUCN assessments, and a recent literature review, to characterise the global trade in amphibians, and also map use by purpose including meat, pets, medicinal, and for research. We show that 1215 species are being traded (17% of amphibian species), almost three times previous recorded numbers, 345 are threatened, and 100 Data Deficient or unassessed. Traded species origin hotspots include South America, China, and Central Africa; sources indicate 42% of amphibians are taken from the wild. Newly described species can be rapidly traded (mean time lag of 6.5 years), including threatened and unassessed species. The scale and limited regulation of the amphibian trade, paired with the triptych of connected pressures (collection, pathogens, invasive species), warrants a re-examination of the wildlife trade status quo, application of the precautionary principle in regard to wildlife trade, and a renewed push to achieve global biodiversity goals. In the last few decades, exotic pets have become much more common. In the UK in 2008, reptiles and amphibians were more popular than dogs, with over eight million in captivity. But while almost all pet cats and dogs are born and bred in captivity, exotic pets are often taken from the wild, putting species and their habitats at risk. An international trade agreement called the Convention on International Trade in Endangered Species (CITES) strives to prevent unsustainable animal trade. But to get CITES protection, species depend on data showing that wildlife trade threatens their survival. In addition, their range countries need to first propose them to be listed. For most wild animal species, there are no data on population size or population decline. In the case of amphibians, CITES regulates the trade of just 2.5% of species. This leaves the rest with no protection from overarching international trade regulations. To protect these animals, researchers need to find out which species are in trade, where they are coming from, and how many are already threatened. To address this, Hughes, Marshall and Strine combined data from five sources, including official CITES trade records, recent research and an online search for amphibian sales in six languages. The data showed evidence of trade in at least 1,215 amphibian species, representing 17% of all amphibians. The figure is three times higher than previous estimates. Of the species in trade, more than one in five is vulnerable to extinction, endangered, or critically endangered. For a further 100 of the traded species, data on population were unavailable. Moreover, analysis of the origins of traded individuals showed that around 42% came from the wild. Tropical parts of the world had the highest number of species in trade, but the data showed exchanges happening across the globe. Unsustainable wildlife trade can have devastating consequences for wild animals. It has already driven at least 21 reptile species to extinction, and data of amphibian species are unknown. To prevent further species going extinct, legal wildlife trade should follow the precautionary principle when it comes to wildlife trade. Rather than allowing people to trade a species until CITES regulates it, a blanket ban should come into force for species that have not been assessed or are threatened. Trade would be able to resume for a species only when assessments show that it would not cause major population decline, or secure, captive breeding facilities can be guaranteed.
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Affiliation(s)
- Alice C Hughes
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Benjamin Michael Marshall
- Institute of Science, School of Biology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Colin Strine
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand, Nakhon Ratchasima, Thailand
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Smilansky V, Jirků M, Milner DS, Ibáñez R, Gratwicke B, Nicholls A, Lukeš J, Chambouvet A, Richards TA. Expanded host and geographic range of tadpole associations with the Severe Perkinsea Infection group. Biol Lett 2021; 17:20210166. [PMID: 34129800 PMCID: PMC8205526 DOI: 10.1098/rsbl.2021.0166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/24/2021] [Indexed: 11/12/2022] Open
Abstract
Severe Perkinsea infection is an emerging disease of amphibians, specifically tadpoles. Disease presentation correlates with liver infections of a subclade of Perkinsea (Alveolata) protists, named Pathogenic Perkinsea Clade (PPC). Tadpole mortality events associated with PPC infections have been reported across North America, from Alaska to Florida. Here, we investigate the geographic and host range of PPC associations in seemingly healthy tadpoles sampled from Panama, a biogeographic provenance critically affected by amphibian decline. To complement this work, we also investigate a mortality event among Hyla arborea tadpoles in captive-bred UK specimens. PPC SSU rDNA was detected in 10 of 81 Panama tadpoles tested, and H. arborea tadpoles from the UK. Phylogenies of the Perkinsea SSU rDNA sequences demonstrate they are highly similar to PPC sequences sampled from mortality events in the USA, and phylogenetic analysis of tadpole mitochondrial SSU rDNA demonstrates, for the first time, PPC associations in diverse hylids. These data provide further understanding of the biogeography and host range of this putative pathogenic group, factors likely to be important for conservation planning.
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Affiliation(s)
- Vanessa Smilansky
- Living Systems Institute and Biosciences, University of Exeter, Exeter, Devon EX4 4QD, UK
| | - Miloslav Jirků
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic
| | - David S. Milner
- Department of Zoology, University of Oxford, Oxford OX1 3SZ, UK
| | - Roberto Ibáñez
- Smithsonian Tropical Research Institute, Panamá, Republic of Panama
- Sistema Nacional de Investigación, SENACYT, Panamá, Republic of Panama
| | - Brian Gratwicke
- Smithsonian National Zoo and Conservation Biology Institute, Washington D.C., USA
| | - Andrew Nicholls
- Department of Zoology, University of Oxford, Oxford OX1 3SZ, UK
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic
- Faculty of Sciences, University of South Bohemia, 370 05 České Budějovice, Czech Republic
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8
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Whitfield SM, Alvarado-Barboza G, Abarca JG, Zumbado-Ulate H, Jimenez RR, Kerby J. Ranavirus is widespread in Costa Rica and co-occurs with threatened amphibians. DISEASES OF AQUATIC ORGANISMS 2021; 144:89-98. [PMID: 33830072 DOI: 10.3354/dao03576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Amphibians are globally threatened by emerging infectious diseases, and ranaviruses are among the most concerning pathogens to threaten species in the wild. We sampled for ranaviruses in wild amphibians at 8 sites in Costa Rica, spanning broad climatic zones and taxonomic associations. Seven of these sites are inhabited by highly threatened amphibian species that persist at low global population sizes after population declines due to amphibian chytridiomycosis. One of the surveyed sites is occupied by an introduced amphibian species, which is relatively rare in Central America but may be an important pathway for long-distance transport of ranaviruses. We detected ranavirus using quantitative polymerase chain reaction in 16.3% of the 243 individuals and among 5 of our 8 sites, but not at the site with the introduced species. Infection prevalence varied among species and sites, but not with mean annual temperature or mean annual precipitation. Infection intensity did not vary with species, site, temperature, or precipitation. Our results show that ranavirus infection is spatially widespread in Costa Rica, affecting a broad range of host species, and occurs across climatic zones-though we encountered no mortality or morbidity in our sampled species. Ranaviruses are known to cause intermittent mass mortality in amphibian populations, and the threatened species sampled here are likely vulnerable to population impacts from emerging ranaviruses. Therefore, we believe the potential impacts of ranaviruses on amphibian populations in tropical regions have likely been underestimated, and that they should be viewed as a potential major stressor to threatened amphibians in tropical regions.
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Wynne FJ, Puschendorf R, Knight ME, Price SJ. Choice of molecular assay determines ranavirus detection probability and inferences about prevalence and occurrence. DISEASES OF AQUATIC ORGANISMS 2020; 141:139-147. [PMID: 32969346 DOI: 10.3354/dao03518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ranaviruses are emerging pathogens that can cause morbidity, mortality and population declines in ectothermic hosts; however, there is no standardized approach to diagnostics. Here, we compared the inter-assay variation and intra-assay precision among 2 commonly used quantitative PCRs (qPCRs), a conventional and a nested PCR assay (used as a gold standard), using laboratory-propagated ranavirus (FV3 and CMTV) and field-collected samples. A qPCR assay ('Leung') detected viral DNA in dilutions 2 orders of magnitude lower than other assays regardless of the viral lineage of the cultured isolate (FV3/CMTV). The second qPCR ('Brunner') was slightly more sensitive than the conventional PCR ('Mao' assay). For field samples, the Leung qPCR detected all known positives, while the Mao assay PCR only detected 2.5% of the positive samples. Amplicon sequences from the 2 conventional PCRs were shown to be useful for inferring viral lineage. Inaccurate results will bias estimates of the distribution and prevalence of ranaviruses, and together these findings emphasize that molecular assays should be chosen carefully in the context of study aims.
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Affiliation(s)
- Felicity J Wynne
- School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, UK
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von Essen M, Leung WTM, Bosch J, Pooley S, Ayres C, Price SJ. High pathogen prevalence in an amphibian and reptile assemblage at a site with risk factors for dispersal in Galicia, Spain. PLoS One 2020; 15:e0236803. [PMID: 32730306 PMCID: PMC7392302 DOI: 10.1371/journal.pone.0236803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 07/14/2020] [Indexed: 12/30/2022] Open
Abstract
Ranaviruses are agents of disease, mortality and population declines in ectothermic vertebrates and emergences have been repeatedly linked to human activities. Ranaviruses in the common midwife toad ranavirus lineage are emerging in Europe. They are known to be severe multi-host pathogens of amphibians and can also cause disease in reptiles. Recurrent outbreaks of ranavirus disease and mortality affecting three species have occurred at a small reservoir in north-west Spain but no data were available on occurrence of the pathogen in the other amphibian and reptile species present or at adjacent sites. We sampled nine species of amphibians and reptiles at the reservoir and nearby sites and screened for ranavirus presence using molecular methods. Our results show infection with ranavirus in all nine species, including first reports for Hyla molleri, Pelophylax perezi, Rana iberica, and Podarcis bocagei. We detected ranavirus in all four local sites and confirmed mass mortality incidents involving Lissotriton boscai and Triturus marmoratus were ongoing. The reservoir regularly hosts water sports tournaments and the risks of ranavirus dispersal through the translocation of contaminated equipment are discussed.
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Affiliation(s)
- Marius von Essen
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
- Imperial College London, Department of Life Sciences (Silwood Park), Ascot, United Kingdom
| | - William T. M. Leung
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- Research Unit of Biodiversity—CSIC/UO/PA, Universidad de Oviedo, Edificio de Investigación, Mieres, Spain
- * E-mail:
| | - Simon Pooley
- Imperial College London, Department of Life Sciences (Silwood Park), Ascot, United Kingdom
| | - Cesar Ayres
- Asociación Herpetológica Española, Madrid, Spain
| | - Stephen J. Price
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, United Kingdom
- UCL Genetics Institute, London, United Kingdom
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Bienentreu JF, Lesbarrères D. Amphibian Disease Ecology: Are We Just Scratching the Surface? HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - David Lesbarrères
- Department of Biology, Laurentian University, Sudbury, ON P3E 2C6, Canada
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Pabijan M, Palomar G, Antunes B, Antoł W, Zieliński P, Babik W. Evolutionary principles guiding amphibian conservation. Evol Appl 2020; 13:857-878. [PMID: 32431739 PMCID: PMC7232768 DOI: 10.1111/eva.12940] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/05/2020] [Accepted: 02/18/2020] [Indexed: 12/18/2022] Open
Abstract
The Anthropocene has witnessed catastrophic amphibian declines across the globe. A multitude of new, primarily human-induced drivers of decline may lead to extinction, but can also push species onto novel evolutionary trajectories. If these are recognized by amphibian biologists, they can be engaged in conservation actions. Here, we summarize how principles stemming from evolutionary concepts have been applied for conservation purposes, and address emerging ideas at the vanguard of amphibian conservation science. In particular, we examine the consequences of increased drift and inbreeding in small populations and their implications for practical conservation. We then review studies of connectivity between populations at the landscape level, which have emphasized the limiting influence of anthropogenic structures and degraded habitat on genetic cohesion. The rapid pace of environmental changes leads to the central question of whether amphibian populations can cope either by adapting to new conditions or by shifting their ranges. We gloomily conclude that extinction seems far more likely than adaptation or range shifts for most species. That said, conservation strategies employing evolutionary principles, such as selective breeding, introduction of adaptive variants through translocations, ecosystem interventions aimed at decreasing phenotype-environment mismatch, or genetic engineering, may effectively counter amphibian decline in some areas or for some species. The spread of invasive species and infectious diseases has often had disastrous consequences, but has also provided some premier examples of rapid evolution with conservation implications. Much can be done in terms of setting aside valuable amphibian habitat that should encompass both natural and agricultural areas, as well as designing protected areas to maximize the phylogenetic and functional diversity of the amphibian community. We conclude that an explicit consideration and application of evolutionary principles, although certainly not a silver bullet, should increase effectiveness of amphibian conservation in both the short and long term.
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Affiliation(s)
- Maciej Pabijan
- Institute of Zoology and Biomedical ResearchFaculty of BiologyJagiellonian UniversityKrakówPoland
| | - Gemma Palomar
- Institute of Environmental SciencesFaculty of BiologyJagiellonian UniversityKrakówPoland
| | - Bernardo Antunes
- Institute of Environmental SciencesFaculty of BiologyJagiellonian UniversityKrakówPoland
| | - Weronika Antoł
- Institute of Environmental SciencesFaculty of BiologyJagiellonian UniversityKrakówPoland
| | - Piotr Zieliński
- Institute of Environmental SciencesFaculty of BiologyJagiellonian UniversityKrakówPoland
| | - Wiesław Babik
- Institute of Environmental SciencesFaculty of BiologyJagiellonian UniversityKrakówPoland
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Characterization of Dermotheca sp. Infection in a midwestern state-endangered salamander ( Ambystoma platineum) and a co-occurring common species ( Ambystoma texanum). Parasitology 2020; 147:360-370. [PMID: 31840622 DOI: 10.1017/s0031182019001677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ichthyosporean parasites (order Dermocystida) can cause morbidity and mortality in amphibians, but their ecology and epidemiology remain understudied. We investigated the prevalence, gross and histologic appearance, and molecular phylogeny of a novel dermocystid in the state-endangered silvery salamander (Ambystoma platineum) and the co-occurring, non-threatened small-mouthed salamander (Ambystoma texanum) from Illinois. Silvery salamanders (N = 610) were sampled at six ephemeral wetlands from 2016 to 2018. Beginning in 2017, 1-3 mm raised, white skin nodules were identified in 24 silvery salamanders and two small-mouthed salamanders from five wetlands (prevalence = 0-11.1%). Skin biopsy histology (N = 4) was consistent with dermocystid sporangia, and necropsies (N = 3) identified infrequent hepatic sporangia. Parasitic 18S rRNA sequences (N = 5) from both salamander species were identical, and phylogenetic analysis revealed a close relationship to Dermotheca viridescens. Dermocystids were not identified in museum specimens from the same wetlands (N = 125) dating back to 1973. This is the first report of Dermotheca sp. affecting caudates in the Midwestern United States. Future research is needed to determine the effects of this pathogen on individual and population health, and to assess whether this organism poses a threat to the conservation of ambystomatid salamanders.
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Sriwanayos P, Subramaniam K, Stilwell NK, Imnoi K, Popov VL, Kanchanakhan S, Polchana J, Waltzek TB. Phylogenomic characterization of ranaviruses isolated from cultured fish and amphibians in Thailand. Facets (Ott) 2020. [DOI: 10.1139/facets-2020-0043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectothermic vertebrates. In this study, we determined the full genomes of eight ranaviruses isolated from marbled sleeper goby ( Oxyeleotris marmorata), goldfish ( Carassius auratus), guppy ( Poecilia reticulata), tiger frog ( Hoplobatrachus tigerinus), Asian grass frog ( Fejervarya limnocharis), and East Asian bullfrog ( H. rugulosus) cultured or imported into Thailand. These ranaviral isolates induced the same cytopathic effects (i.e., progression of coalescing round plaques) in epithelioma papulosum cyprini (EPC) cell cultures. Transmission electron microscopy of infected EPC cells revealed cytoplasmic viral particles with ultrastructural features typical for ranaviruses. Pairwise genetic comparisons of the complete major capsid protein coding sequences from the Thai ranaviruses displayed the highest identity (99.8%–100%) to a ranavirus (tiger frog virus; TFV) isolated from diseased tiger frogs cultured in China, a slightly lower identity (99.3%–99.4%) to a ranavirus (Wamena virus; WV) isolated from diseased green tree pythons ( Morelia viridis) illegally exported from Papua New Guinea, and a lower identity to 35 other ranaviruses (93.7%–98.6%). Phylogenomic analyses supported the eight Thai ranaviruses, Chinese TFV, and WV as a subclade within a larger frog virus 3 clade. Our findings confirm the spread of TFV among cultured fish and amphibians in Asia and likely in reptiles in Oceania. Biosecurity measures are needed to ensure TFV does not continue to spread throughout Southeast Asia and to other parts of the world via international trade.
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Affiliation(s)
- Preeyanan Sriwanayos
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Natalie K. Stilwell
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Kamonchai Imnoi
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Vsevolod L. Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Somkiat Kanchanakhan
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
- Department of Fisheries, Chonburi Provincial Fishery Office, Chonburi 20000, Thailand
| | - Jaree Polchana
- Aquatic Animal Health Research and Development Division, Department of Fisheries, Bangkok 10900, Thailand
| | - Thomas B. Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
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15
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Vilaça ST, Bienentreu JF, Brunetti CR, Lesbarrères D, Murray DL, Kyle CJ. Frog Virus 3 Genomes Reveal Prevalent Recombination between Ranavirus Lineages and Their Origins in Canada. J Virol 2019; 93:e00765-19. [PMID: 31341053 PMCID: PMC6798099 DOI: 10.1128/jvi.00765-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/10/2019] [Indexed: 12/14/2022] Open
Abstract
Ranaviruses are pathogens associated with the decline of amphibian populations across much of their distribution. In North America, frog virus 3 (FV3) is a widely distributed pathogen with wild populations of amphibians harboring different lineages and putative recombinants between FV3 and common midwife toad virus (CMTV). These recombinants have higher pathogenicity, and CMTV-derived genes associated with virulence are reported in wild strains in Canada. However, while FV3 is linked to amphibian die-offs in North America, CMTVs have been reported only in commercial frog farms in North America. We sequenced complete genomes of 18 FV3 isolates from three amphibian species to characterize genetic diversity of the lineages in Canada and infer possible recombinant regions. The 18 FV3 isolates displayed different signals of recombination, varying from none to interspersed recombination with previously isolated CMTV-like viruses. In general, most recombination breakpoints were located within open reading frames (ORFs), generating new ORFs and proteins that were a mixture between FV3 and CMTV. A combined spatial and temporal phylogeny suggests the presence of the FV3 lineage in Canada is relatively contemporary (<100 years), corroborating the hypothesis that both CMTV- and FV3-like viruses spread to North America when the international commercial amphibian trade started. Our results highlight the importance of pathogen surveillance and viral dynamics using full genomes to more clearly understand the mechanisms of disease origin and spread.IMPORTANCE Amphibian populations are declining worldwide, and these declines have been linked to a number of anthropogenic factors, including disease. Among the pathogens associated with amphibian mortality, ranaviruses have caused massive die-offs across continents. In North America, frog virus 3 (FV3) is a widespread ranavirus that can infect wild and captive amphibians. In this study, we sequenced full FV3 genomes isolated from frogs in Canada. We report widespread recombination between FV3 and common midwife toad virus (CMTV). Phylogenies indicate a recent origin for FV3 in Canada, possibly as a result of international amphibian trade.
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Affiliation(s)
- Sibelle T Vilaça
- Biology Department, Trent University, Peterborough, Ontario, Canada
| | - Joe-Felix Bienentreu
- Genetics and Ecology of Amphibian Research Group (GEARG), Department of Biology, Laurentian University, Sudbury, Ontario, Canada
| | - Craig R Brunetti
- Biology Department, Trent University, Peterborough, Ontario, Canada
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - David Lesbarrères
- Genetics and Ecology of Amphibian Research Group (GEARG), Department of Biology, Laurentian University, Sudbury, Ontario, Canada
| | - Dennis L Murray
- Biology Department, Trent University, Peterborough, Ontario, Canada
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - Christopher J Kyle
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
- Forensic Science Department, Trent University, Peterborough, Ontario, Canada
- Natural Resources DNA Profiling and Forensics Centre, Trent University, Peterborough, Ontario, Canada
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16
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Hernández-Martínez LÁ, Romero-Méndez U, González-Barrios JL, García-De la Peña MC, Amézquita-Torres A. Nuevos registros y prevalencia de Batrachochytrium dendrobatidis en anuros de la cuenca Nazas-Aguanaval en la región norte-centro de México. REV MEX BIODIVERS 2019. [DOI: 10.22201/ib.20078706e.2019.90.2934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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17
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Brunner JL, Olson AD, Rice JG, Meiners SE, Le Sage MJ, Cundiff JA, Goldberg CS, Pessier AP. Ranavirus infection dynamics and shedding in American bullfrogs: consequences for spread and detection in trade. DISEASES OF AQUATIC ORGANISMS 2019; 135:135-150. [PMID: 31392966 DOI: 10.3354/dao03387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
American bullfrogs Lithobates catesbeianus are thought to be important in the global spread of ranaviruses-often lethal viruses of cold-blooded vertebrates-because they are commonly farmed, dominate international trade, and may be 'carriers' of ranavirus infections. However, whether American bullfrogs are easily infected and maintain long-lasting ranavirus infections, or are refractory to or rapidly clear infections, remains unknown. We tracked the dynamics of ranavirus in American bullfrogs through time and with temperature in multiple types of samples and also screened shipments from commercial suppliers to determine whether we could detect subclinical infections. Collectively, we found that tadpoles and juveniles were commonly infected at moderate doses, and while some died, others controlled and appeared to clear their infections. Some individuals, however, harbored subclinical infections for up to 49 d, suggesting that American bullfrogs may be important carriers. Indeed, tadpoles and metamorphosed frogs from 2 of 5 commercial suppliers harbored subclinicial infections. Juveniles at warmer temperatures had less intense but still persistent infections. Because diagnostic performance was strongly related to infection intensity, non-lethal samples (i.e. tail or toe clips, swabs, and environmental DNA) had only a moderate chance of detecting subclinical infections. Even internal tissues may fail to detect subclinical infections. However, viral shedding was correlated with the intensity of infection, so while subclinically infected tadpoles shed virus for 35-49 d, the low levels might lead to little transmission. We suggest that a quantitative focus on virus dynamics within hosts can provide a more nuanced view of ranavirus infections and the risk presented by American bullfrogs in trade.
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Affiliation(s)
- Jesse L Brunner
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
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18
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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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19
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Subramaniam K, Waltzek TB, Chinchar VG. Genomic sequence of a Bohle iridovirus strain isolated from a diseased boreal toad (Anaxyrus boreas boreas) in a North American aquarium. Arch Virol 2019; 164:1923-1926. [PMID: 30993463 DOI: 10.1007/s00705-019-04244-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/11/2019] [Indexed: 11/25/2022]
Abstract
Genomic sequence analysis of zoo ranavirus (ZRV) suggests it is a strain of Bohle iridovirus (BIV), a virus that was first detected in, and thought to be confined to, Australia. Furthermore, marked sequence similarity and genomic co-linearity among ZRV, BIV, and German gecko ranavirus (GGRV) are consistent with the view that all three are strains of Frog virus 3, the type species of the genus Ranavirus, family Iridoviridae.
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Affiliation(s)
- Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - V Gregory Chinchar
- Department of Microbiology and Immunology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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20
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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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21
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More S, Angel Miranda M, Bicout D, Bøtner A, Butterworth A, Calistri P, Depner K, Edwards S, Garin-Bastuji B, Good M, Michel V, Raj M, Saxmose Nielsen S, Sihvonen L, Spoolder H, Stegeman JA, Thulke HH, Velarde A, Willeberg P, Winckler C, Baláž V, Martel A, Murray K, Fabris C, Munoz-Gajardo I, Gogin A, Verdonck F, Gortázar Schmidt C. Risk of survival, establishment and spread of Batrachochytrium salamandrivorans (Bsal) in the EU. EFSA J 2018; 16:e05259. [PMID: 32625888 PMCID: PMC7009437 DOI: 10.2903/j.efsa.2018.5259] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen of salamanders. Despite limited surveillance, Bsal was detected in kept salamanders populations in Belgium, Germany, Spain, the Netherlands and the United Kingdom, and in wild populations in some regions of Belgium, Germany and the Netherlands. According to niche modelling, at least part of the distribution range of every salamander species in Europe overlaps with the climate conditions predicted to be suitable for Bsal. Passive surveillance is considered the most suitable approach for detection of Bsal emergence in wild populations. Demonstration of Bsal absence is considered feasible only in closed populations of kept susceptible species. In the wild, Bsal can spread by both active (e.g. salamanders, anurans) and passive (e.g. birds, water) carriers; it is most likely maintained/spread in infected areas by contacts of salamanders or by interactions with anurans, whereas human activities most likely cause Bsal entry into new areas and populations. In kept amphibians, Bsal contamination via live silent carriers (wild birds and anurans) is considered extremely unlikely. The risk-mitigation measures that were considered the most feasible and effective: (i) for ensuring safer international or intra-EU trade of live salamanders, are: ban or restrictions on salamander imports, hygiene procedures and good practice manuals; (ii) for protecting kept salamanders from Bsal, are: identification and treatment of positive collections; (iii) for on-site protection of wild salamanders, are: preventing translocation of wild amphibians and release/return to the wild of kept/temporarily housed wild salamanders, and setting up contact points/emergency teams for passive surveillance. Combining several risk-mitigation measures improve the overall effectiveness. It is recommended to: introduce a harmonised protocol for Bsal detection throughout the EU; improve data acquisition on salamander abundance and distribution; enhance passive surveillance activities; increase public and professionals' awareness; condition any movement of captive salamanders on Bsal known health status.
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22
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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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23
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Bush CL, Guzy JC, Halloran KM, Swartwout MC, Kross CS, Willson JD. Distribution and Abundance of Introduced Seal Salamanders (Desmognathus monticola) in Northwest Arkansas, USA. COPEIA 2017. [DOI: 10.1643/ch-17-579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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Co-occurrence and Hybridization between Necturus maculosus and a Heretofore Unknown Necturus in the Southern Appalachians. J HERPETOL 2017. [DOI: 10.1670/17-006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Saucedo B, Hughes J, van Beurden SJ, Suárez NM, Haenen OLM, Voorbergen-Laarman M, Gröne A, Kik MJL. Complete Genome Sequence of Frog virus 3, Isolated from a Strawberry Poison Frog ( Oophaga pumilio) Imported from Nicaragua into the Netherlands. GENOME ANNOUNCEMENTS 2017; 5:e00863-17. [PMID: 28860243 PMCID: PMC5578841 DOI: 10.1128/genomea.00863-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/12/2017] [Indexed: 01/13/2023]
Abstract
Frog virus 3 was isolated from a strawberry poison frog (Oophaga pumilio) imported from Nicaragua via Germany to the Netherlands, and its complete genome sequence was determined. Frog virus 3 isolate Op/2015/Netherlands/UU3150324001 is 107,183 bp long and has a nucleotide similarity of 98.26% to the reference Frog virus 3 isolate.
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Affiliation(s)
| | - Joseph Hughes
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | | | - Nicolás M Suárez
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Olga L M Haenen
- Wageningen Bioveterinary Research of Wageningen UR, Lelystad, the Netherlands
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26
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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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27
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Claytor SC, Subramaniam K, Landrau-Giovannetti N, Chinchar VG, Gray MJ, Miller DL, Mavian C, Salemi M, Wisely S, Waltzek TB. Ranavirus phylogenomics: Signatures of recombination and inversions among bullfrog ranaculture isolates. Virology 2017; 511:330-343. [PMID: 28803676 DOI: 10.1016/j.virol.2017.07.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 07/12/2017] [Accepted: 07/24/2017] [Indexed: 01/23/2023]
Abstract
Ranaviruses are emerging pathogens of fish, amphibians, and reptiles that threaten aquatic animal industries and wildlife worldwide. Our objective was to genetically characterize ranaviruses isolated during separate bullfrog Lithobates catesbeianus die-offs that occurred eight years apart on the same North American farm. The earlier outbreak was due to a highly pathogenic strain of common midwife toad virus (CMTV) previously known only from Europe and China. The later outbreak was due to a chimeric ranavirus that displayed a novel genome arrangement and a DNA backbone typical for Frog virus 3 (FV3) strains except for interspersed fragments acquired through recombination with the CMTV isolated earlier. Both bullfrog ranaviruses are more pathogenic than wild-type FV3 suggesting recombination may have resulted in the increased pathogenicity observed in the ranavirus isolated in the later outbreak. Our study underscores the role international trade in farmed bullfrogs may have played in the global dissemination of highly pathogenic ranaviruses.
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Affiliation(s)
- Sieara C Claytor
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, USA
| | | | | | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee, Knoxville, TN, USA
| | - Debra L Miller
- Center for Wildlife Health, University of Tennessee, Knoxville, TN, USA
| | - Carla Mavian
- Department of Pathology, Immunology, and Laboratory Medicine, and Emerging Pathogens Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marco Salemi
- Department of Pathology, Immunology, and Laboratory Medicine, and Emerging Pathogens Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Samantha Wisely
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, USA.
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28
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DETECTION AND REPORTING OF RANAVIRUS IN AMPHIBIANS: EVALUATION OF THE ROLES OF THE WORLD ORGANISATION FOR ANIMAL HEALTH AND THE PUBLISHED LITERATURE. J Wildl Dis 2017; 53:509-520. [PMID: 28402726 DOI: 10.7589/2016-08-176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pathogens of wildlife can have direct impacts on human and livestock health as well as on biodiversity, as causative factors in population declines and extinctions. The World Organization for Animal Health (OIE) seeks to facilitate rapid sharing of information about animal diseases to enable up-to-date risk assessments of translocations of animals and animal products. The OIE also produces manuals of recommended methods to standardize diagnostic testing. Ranaviruses are important amphibian pathogens that may have spread through international trade, and infections became notifiable to OIE in 2009. We surveyed and reviewed published literature for data on sampling, diagnostic testing, and reporting of ranavirus during 2009-14. We also investigated attitudes and awareness of the OIE and its recommendations for best practice. We found that sampling effort is uneven and concentrated in the northern hemisphere. We also identified citizen science projects that have the potential to improve the quantity and quality of data on the incidence of ranavirus infection and the circumstances surrounding disease outbreaks. We found reporting of infection to be inconsistent: reporting was split between the published literature (where it was subject to a 2-yr lag) and the OIE with little overlap, results of negative diagnostic tests were underreported, and scientific researchers lacked awareness of the role of the OIE. Approaches to diagnostic screening were poorly harmonized and heavily reliant on molecular methods. These flaws in the mechanisms of ranavirus detection and reporting hamper the construction of a comprehensive disease information database.
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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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Wombwell EL, Garner TWJ, Cunningham AA, Quest R, Pritchard S, Rowcliffe JM, Griffiths RA. Detection of Batrachochytrium dendrobatidis in Amphibians Imported into the UK for the Pet Trade. ECOHEALTH 2016; 13:456-466. [PMID: 27317049 DOI: 10.1007/s10393-016-1138-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 05/18/2016] [Accepted: 05/28/2016] [Indexed: 06/06/2023]
Abstract
There is increasing evidence that the global spread of the fungal pathogen Batrachochytrium dendrobatidis (Bd) has been facilitated by the international trade in amphibians. Bd was first detected in the UK in 2004, and has since been detected in multiple wild amphibian populations. Most amphibians imported into the UK for the pet trade from outside the European Union enter the country via Heathrow Animal Reception Centre (HARC), where Bd-positive animals have been previously detected. Data on the volume, diversity and origin of imported amphibians were collected for 59 consignments arriving at HARC between November 2009 and June 2012, along with a surveillance study to investigate the prevalence of Bd in these animals. Forty-three amphibian genera were recorded, originating from 12 countries. It was estimated that 5000-7000 amphibians are imported through HARC into the UK annually for the pet trade. Bd was detected in consignments from the USA and Tanzania, in six genera, resulting in an overall prevalence of 3.6%. This suggests that imported amphibians are a source of Bd within the international pet trade.
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Affiliation(s)
- Emma Louise Wombwell
- Institute of Zoology, Zoological Society of London, Regent's Park, London, UK.
- School of Anthropology and Conservation, Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, UK.
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, Regent's Park, London, UK
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, UK
| | - Robert Quest
- Heathrow Animal Reception Centre, City of London Corporation, Animal Health and Welfare Services, London, UK
| | - Susie Pritchard
- Heathrow Animal Reception Centre, City of London Corporation, Animal Health and Welfare Services, London, UK
| | - J Marcus Rowcliffe
- Institute of Zoology, Zoological Society of London, Regent's Park, London, UK
| | - Richard A Griffiths
- School of Anthropology and Conservation, Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, UK
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Yap TA, Gillespie L, Ellison S, Flechas SV, Koo MS, Martinez AE, Vredenburg VT. Invasion of the Fungal Pathogen Batrachochytrium dendrobatidis on California Islands. ECOHEALTH 2016; 13:145-150. [PMID: 26493624 DOI: 10.1007/s10393-015-1071-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/22/2015] [Accepted: 09/23/2015] [Indexed: 06/05/2023]
Abstract
Batrachochytrium dendrobatidis (Bd), an amphibian fungal pathogen, has infected >500 species and caused extinctions or declines in >200 species worldwide. Despite over a decade of research, little is known about its invasion biology. To better understand this, we conducted a museum specimen survey (1910-1997) of Bd in amphibians on 11 California islands and found a pattern consistent with the emergence of Bd epizootics on the mainland, suggesting that geographic isolation did not prevent Bd invasion. We propose that suitable habitat, host diversity, and human visitation overcome isolation from the mainland and play a role in Bd invasion.
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Affiliation(s)
- Tiffany A Yap
- Institute of the Environment and Sustainability, University of California, La Kretz Hall, Suite 300, 619 Charles E Young Drive, Los Angeles, CA, 90095, USA
- Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building #3160, Berkeley, CA, 94720, USA
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA
| | - Lauren Gillespie
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA
| | - Silas Ellison
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de los Andes, Bogotá, AA 4976, Colombia
| | - Michelle S Koo
- Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building #3160, Berkeley, CA, 94720, USA
| | - Ari E Martinez
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA
| | - Vance T Vredenburg
- Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building #3160, Berkeley, CA, 94720, USA.
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA.
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Warne RW, LaBumbard B, LaGrange S, Vredenburg VT, Catenazzi A. Co-Infection by Chytrid Fungus and Ranaviruses in Wild and Harvested Frogs in the Tropical Andes. PLoS One 2016; 11:e0145864. [PMID: 26726999 PMCID: PMC4701007 DOI: 10.1371/journal.pone.0145864] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
While global amphibian declines are associated with the spread of Batrachochytrium dendrobatidis (Bd), undetected concurrent co-infection by other pathogens may be little recognized threats to amphibians. Emerging viruses in the genus Ranavirus (Rv) also cause die-offs of amphibians and other ectotherms, but the extent of their distribution globally, or how co-infections with Bd impact amphibians are poorly understood. We provide the first report of Bd and Rv co-infection in South America, and the first report of Rv infections in the amphibian biodiversity hotspot of the Peruvian Andes, where Bd is associated with extinctions. Using these data, we tested the hypothesis that Bd or Rv parasites facilitate co-infection, as assessed by parasite abundance or infection intensity within individual adult frogs. Co-infection occurred in 30% of stream-dwelling frogs; 65% were infected by Bd and 40% by Rv. Among terrestrial, direct-developing Pristimantis frogs 40% were infected by Bd, 35% by Rv, and 20% co-infected. In Telmatobius frogs harvested for the live-trade 49% were co-infected, 92% were infected by Bd, and 53% by Rv. Median Bd and Rv loads were similar in both wild (Bd = 101.2 Ze, Rv = 102.3 viral copies) and harvested frogs (Bd = 103.1 Ze, Rv = 102.7 viral copies). While neither parasite abundance nor infection intensity were associated with co-infection patterns in adults, these data did not include the most susceptible larval and metamorphic life stages. These findings suggest Rv distribution is global and that co-infection among these parasites may be common. These results raise conservation concerns, but greater testing is necessary to determine if parasite interactions increase amphibian vulnerability to secondary infections across differing life stages, and constitute a previously undetected threat to declining populations. Greater surveillance of parasite interactions may increase our capacity to contain and mitigate the impacts of these and other wildlife diseases.
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Affiliation(s)
- Robin W. Warne
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
- * E-mail:
| | - Brandon LaBumbard
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
| | - Seth LaGrange
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
| | - Vance T. Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, United States of America
| | - Alessandro Catenazzi
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
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Abstract
Alien herpetofauna have a broad diversity of ecological and evolutionary impacts, involving seven mechanisms. Ecological impacts usually result from trophic disruptions and may be direct or indirect and top-down or bottom-up; they may vary in scale from single species to communities. A single species may impose impacts involving most or all of these categories. Evolutionary impacts most often result from hybridization and introgression but may include diverse changes in native fauna induced by selection. Impact magnitudes observed to date largely range from moderate to major, but massive impacts (including species extinction) are known for a handful of invasive species. Research remains skewed toward a small sample of all invaders, and major research gaps remain in understanding community-level impacts, the risk posed by competition, determinants of predation impact, the relevance of genetic diversity to impacts, and how to predict impacts.
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Affiliation(s)
- Fred Kraus
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
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Epstein B, Storfer A. Comparative Genomics of an Emerging Amphibian Virus. G3 (BETHESDA, MD.) 2015; 6:15-27. [PMID: 26530419 PMCID: PMC4704714 DOI: 10.1534/g3.115.023762] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/22/2015] [Indexed: 11/18/2022]
Abstract
Ranaviruses, a genus of the Iridoviridae, are large double-stranded DNA viruses that infect cold-blooded vertebrates worldwide. Ranaviruses have caused severe epizootics in commercial frog and fish populations, and are currently classified as notifiable pathogens in international trade. Previous work shows that a ranavirus that infects tiger salamanders throughout Western North America (Ambystoma tigrinum virus, or ATV) is in high prevalence among salamanders in the fishing bait trade. Bait ATV strains have elevated virulence and are transported long distances by humans, providing widespread opportunities for pathogen pollution. We sequenced the genomes of 15 strains of ATV collected from tiger salamanders across western North America and performed phylogenetic and population genomic analyses and tests for recombination. We find that ATV forms a monophyletic clade within the rest of the Ranaviruses and that it likely emerged within the last several thousand years, before human activities influenced its spread. We also identify several genes under strong positive selection, some of which appear to be involved in viral virulence and/or host immune evasion. In addition, we provide support for the pathogen pollution hypothesis with evidence of recombination among ATV strains, and potential bait-endemic strain recombination.
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Affiliation(s)
- Brendan Epstein
- School of Biological Sciences, Washington State University, Pullman, Washington 99164
| | - Andrew Storfer
- School of Biological Sciences, Washington State University, Pullman, Washington 99164
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D'Aoust-Messier AM, Echaubard P, Billy V, Lesbarrères D. Amphibian pathogens at northern latitudes: presence of chytrid fungus and ranavirus in northeastern Canada. DISEASES OF AQUATIC ORGANISMS 2015; 113:149-155. [PMID: 25751857 DOI: 10.3354/dao02837] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Infections by the fungal pathogen Batrachochytrium dendrobatidis (Bd) and members of the genus Ranavirus (Rv) are increasingly reported as significant determinants of amphibian population die-offs. The complexity associated with their transmission and spatial distribution leads to an increase in demand for comprehensive reporting systems and global mapping of their distribution. Here, we document the distribution of these 2 pathogens in a remote northern temperate lowland where environmental sensitivity is high, providing important insight into the pathogens' natural history and infection patterns. Wood frog Lithobates sylvaticus tissues were collected from the James Bay area in northeastern Canada and were screened for the presence of Bd and Rv using conventional and real-time PCR. Both pathogens were present in the study area, which is the northernmost record in eastern North America. Interestingly, different patterns of distribution were observed between the eastern and western coasts of James Bay, suggesting differences in the spatial and transmission dynamics for each pathogen. Anthropogenic introduction may still influence the distribution patterns observed, even at these latitudes. The presence of infections in this remote area also raises further questions on the risk these pathogens pose to northern amphibian communities. We encourage further research in remote locations for a better understanding of these pathogens, their transmission dynamics, and especially their respective impacts on amphibian populations worldwide.
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Ecological Effects and Human Use of Commercial Mosquito Insecticides in Aquatic Communities. J HERPETOL 2015. [DOI: 10.1670/13-036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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Tompkins DM, Carver S, Jones ME, Krkošek M, Skerratt LF. Emerging infectious diseases of wildlife: a critical perspective. Trends Parasitol 2015; 31:149-59. [PMID: 25709109 DOI: 10.1016/j.pt.2015.01.007] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 01/07/2015] [Accepted: 01/22/2015] [Indexed: 12/20/2022]
Abstract
We review the literature to distinguish reports of vertebrate wildlife disease emergence with sufficient evidence, enabling a robust assessment of emergence drivers. For potentially emerging agents that cannot be confirmed, sufficient data on prior absence (or a prior difference in disease dynamics) are frequently lacking. Improved surveillance, particularly for neglected host taxa, geographical regions and infectious agents, would enable more effective management should emergence occur. Exposure to domestic sources of infection and human-assisted exposure to wild sources were identified as the two main drivers of emergence across host taxa; the domestic source was primary for fish while the wild source was primary for other taxa. There was generally insufficient evidence for major roles of other hypothesized drivers of emergence.
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Affiliation(s)
| | - Scott Carver
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Menna E Jones
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St, Toronto, ON, M5S 3G5, Canada
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
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Une Y, Kudo T, Tamukai K, Murakami M. Epidemic ranaviral disease in imported captive frogs (Dendrobates and Phyllobates spp.), Japan, 2012: a first report. JMM Case Rep 2014. [DOI: 10.1099/jmmcr.0.001198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yumi Une
- Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1‐17‐71 Fuchinobe, Chuo‐ku, Sagamihara, Kanagawa 252‐5201, Japan
| | - Tomoo Kudo
- Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1‐17‐71 Fuchinobe, Chuo‐ku, Sagamihara, Kanagawa 252‐5201, Japan
| | - Ken‐ichi Tamukai
- Den‐enchofu Animal Hospital, 2‐1‐3 Denenchofu, Ota‐ku, Tokyo 145‐0071, Japan
| | - Masaru Murakami
- Laboratory of Molecular Biology, School of Veterinary Medicine, Azabu University, 1‐17‐71 Fuchinobe, Chuo‐ku, Sagamihara, Kanagawa 252‐5201, Japan
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Tamukai K, Une Y, Tominaga A, Suzuki K, Goka K. Batrachochytrium dendrobatidis prevalence and haplotypes in domestic and imported pet amphibians in Japan. DISEASES OF AQUATIC ORGANISMS 2014; 109:165-175. [PMID: 24991744 DOI: 10.3354/dao02732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The international trade in amphibians is believed to have increased the spread of Batrachochytrium dendrobatidis (Bd), the fungal pathogen responsible for chytridiomycosis, which has caused a rapid decline in amphibian populations worldwide. We surveyed amphibians imported into Japan and those held in captivity for a long period or bred in Japan to clarify the Bd infection status. Samples were taken from 820 individuals of 109 amphibian species between 2008 and 2011 and were analyzed by a nested-PCR assay. Bd prevalence in imported amphibians was 10.3% (58/561), while it was 6.9% (18/259) in those in private collections and commercially bred amphibians in Japan. We identified the genotypes of this fungus using partial DNA sequences of the internal transcribed spacer (ITS) region. Sequencing of PCR products of all 76 Bd-positive samples revealed 11 haplotypes of the Bd ITS region. Haplotype A (DNA Data Bank of Japan accession number AB435211) was found in 90% (52/58) of imported amphibians. The results show that Bd is currently entering Japan via the international trade in exotic amphibians as pets, suggesting that the trade has indeed played a major role in the spread of Bd.
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Affiliation(s)
- Kenichi Tamukai
- Den-en-chofu Animal Hospital, 2-1-3 Denenchofu, Ota-ku, Tokyo 145-0071, Japan
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First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in Hong Kong amphibian trade. PLoS One 2014; 9:e90750. [PMID: 24599268 PMCID: PMC3944218 DOI: 10.1371/journal.pone.0090750] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/03/2014] [Indexed: 11/19/2022] Open
Abstract
The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong's trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment.
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Abrams AJ, Cannatella DC, Hillis DM, Sawyer SL. Recent host-shifts in ranaviruses: signatures of positive selection in the viral genome. J Gen Virol 2013; 94:2082-2093. [PMID: 23784445 DOI: 10.1099/vir.0.052837-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ranaviruses have been implicated in recent declines in global amphibian populations. Compared with the family Iridoviridae, to which the genus Ranavirus belongs, ranaviruses have a wide host range in that species/strains are known to infect fish, amphibians and reptiles, presumably due to recent host-switching events. We used eight sequenced ranavirus genomes and two selection-detection methods (site based and branch based) to identify genes that exhibited signatures of positive selection, potentially due to the selective pressures at play during host switching. We found evidence of positive selection acting on four genes via the site-based method, three of which were newly acquired genes unique to ranavirus genomes. Using the branch-based method, we identified eight additional candidate genes that exhibited signatures of dN/dS (non-synonymous/synonymous substitution rate) >1 in the clade where intense host switching had occurred. We found that these branch-specific patterns of elevated dN/dS were enriched in a small group of viral genes that have been acquired most recently in the ranavirus genome, compared with core genes that are shared among all members of the family Iridoviridae. Our results suggest that the group of newly acquired genes in the ranavirus genome may have undergone recent adaptive changes that have facilitated interspecies and interclass host switching.
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Affiliation(s)
- A Jeanine Abrams
- Section of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - David C Cannatella
- Section of Integrative Biology and Texas Memorial Museum, University of Texas, Austin, TX 78712, USA
| | - David M Hillis
- Section of Integrative Biology and Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712, USA
| | - Sara L Sawyer
- Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA
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EFFICACY OF TREATMENT AND LONG-TERM FOLLOW-UP OFBATRACHOCHYTRIUM DENDROBATIDISPCR-POSITIVE ANURANS FOLLOWING ITRACONAZOLE BATH TREATMENT. J Zoo Wildl Med 2013; 44:395-403. [DOI: 10.1638/2012-0219r.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Stöhr AC, Hoffmann A, Papp T, Robert N, Pruvost NBM, Reyer HU, Marschang RE. Long-term study of an infection with ranaviruses in a group of edible frogs (Pelophylax kl. esculentus) and partial characterization of two viruses based on four genomic regions. Vet J 2013; 197:238-44. [PMID: 23535222 DOI: 10.1016/j.tvjl.2013.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/18/2013] [Accepted: 02/15/2013] [Indexed: 11/26/2022]
Abstract
Several edible frogs (Pelophylax kl. esculentus) collected into a single group from various ponds in Europe died suddenly with reddening of the skin (legs, abdomen) and haemorrhages in the gastrointestinal tract. Ranavirus was detected in some of the dead frogs using PCR, and virus was also isolated in cell culture. Over the following 3 years, another two outbreaks occurred with low to high mortality in between asymptomatic periods. In the first 2 years, the same ranavirus was detected repeatedly, but a new ranavirus was isolated in association with the second mass-mortality event. The two different ranaviruses were characterized based on nucleotide sequences from four genomic regions, namely, major capsid protein, DNA polymerase, ribonucleoside diphosphate reductase alpha and beta subunit genes. The sequences showed slight variations to each other or GenBank entries and both clustered to the Rana esculenta virus (REV-like) clade in the phylogenetic analysis. Furthermore, a quiescent infection was demonstrated in two individuals. By comparing samples taken before and after transport and caging in groups it was possible to identify the pond of origin and a ranavirus was detected for the first time in wild amphibians in Germany.
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Affiliation(s)
- Anke C Stöhr
- Fachgebiet für Umwelt- und Tierhygiene, Universität Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
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Olson DH, Aanensen DM, Ronnenberg KL, Powell CI, Walker SF, Bielby J, Garner TWJ, Weaver G, Fisher MC. Mapping the global emergence of Batrachochytrium dendrobatidis, the amphibian chytrid fungus. PLoS One 2013; 8:e56802. [PMID: 23463502 PMCID: PMC3584086 DOI: 10.1371/journal.pone.0056802] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 01/16/2013] [Indexed: 11/29/2022] Open
Abstract
The rapid worldwide emergence of the amphibian pathogen Batrachochytrium dendrobatidis (Bd) is having a profound negative impact on biodiversity. However, global research efforts are fragmented and an overarching synthesis of global infection data is lacking. Here, we provide results from a community tool for the compilation of worldwide Bd presence and report on the analyses of data collated over a four-year period. Using this online database, we analysed: 1) spatial and taxonomic patterns of infection, including amphibian families that appear over- and under-infected; 2) relationships between Bd occurrence and declining amphibian species, including associations among Bd occurrence, species richness, and enigmatic population declines; and 3) patterns of environmental correlates with Bd, including climate metrics for all species combined and three families (Hylidae, Bufonidae, Ranidae) separately, at both a global scale and regional (U.S.A.) scale. These associations provide new insights for downscaled hypothesis testing. The pathogen has been detected in 52 of 82 countries in which sampling was reported, and it has been detected in 516 of 1240 (42%) amphibian species. We show that detected Bd infections are related to amphibian biodiversity and locations experiencing rapid enigmatic declines, supporting the hypothesis that greater complexity of amphibian communities increases the likelihood of emergence of infection and transmission of Bd. Using a global model including all sampled species, the odds of Bd detection decreased with increasing temperature range at a site. Further consideration of temperature range, rather than maximum or minimum temperatures, may provide new insights into Bd-host ecology. Whereas caution is necessary when interpreting such a broad global dataset, the use of our pathogen database is helping to inform studies of the epidemiology of Bd, as well as enabling regional, national, and international prioritization of conservation efforts. We provide recommendations for adaptive management to enhance the database utility and relevance.
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Affiliation(s)
- Deanna H Olson
- Pacific Northwest Research Station, U.S. Forest Service, Corvallis, Oregon, USA.
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Ryan ME, Johnson JR, Fitzpatrick BM, Lowenstine LJ, Picco AM, Shaffer HB. Lethal effects of water quality on threatened California salamanders but not on co-occurring hybrid salamanders. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2013; 27:95-102. [PMID: 23140535 DOI: 10.1111/j.1523-1739.2012.01955.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 07/09/2012] [Indexed: 06/01/2023]
Abstract
Biological invasions and habitat alteration are often detrimental to native species, but their interactions are difficult to predict. Interbreeding between native and introduced species generates novel genotypes and phenotypes, and human land use alters habitat structure and chemistry. Both invasions and habitat alteration create new biological challenges and opportunities. In the intensively farmed Salinas Valley, California (U.S.A.), threatened California tiger salamanders (Ambystoma californiense) have been replaced by hybrids between California tiger salamander and introduced barred tiger salamanders (Ambystoma tigrinum mavortium). We conducted an enclosure experiment to examine the effects habitat modification and relative frequency of hybrid and native California tiger salamanders have on recruitment of salamanders and their prey, Pacific chorus frogs (Pseudacris regilla). We tested whether recruitment differed among genetic classes of tiger salamanders (hybrid or native) and pond hydroperiod (seasonal or perennial). Roughly 6 weeks into the experiment, 70% (of 378 total) of salamander larvae died in 4 out of 6 ponds. Native salamanders survived (n = 12) in these ponds only if they had metamorphosed prior to the die-offs. During die-offs, all larvae of native salamanders died, whereas 56% of hybrid larvae died. We necropsied native and hybrid salamanders, tested water quality, and queried the California Department of Pesticide Regulation database to investigate possible causes of the die-offs. Salamander die-offs, changes in the abundance of other community members (invertebrates, algae, and cyanobacteria), shifts in salamander sex ratio, and patterns of pesticide application in adjacent fields suggest that pesticide use may have contributed to die-offs. That all survivors were hybrids suggests that environmental stress may promote rapid displacement of native genotypes.
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Affiliation(s)
- Maureen E Ryan
- Department of Evolution and Ecology, and Center for Population Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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Gilbert M, Bickford D, Clark L, Johnson A, Joyner PH, Ogg Keatts L, Khammavong K, Nguyễn Văn L, Newton A, Seow TPW, Roberton S, Silithammavong S, Singhalath S, Yang A, Seimon TA. Amphibian pathogens in Southeast Asian frog trade. ECOHEALTH 2012; 9:386-398. [PMID: 23404036 DOI: 10.1007/s10393-013-0817-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 12/14/2012] [Accepted: 12/14/2012] [Indexed: 06/01/2023]
Abstract
Amphibian trade is known to facilitate the geographic spread of pathogens. Here we assess the health of amphibians traded in Southeast Asia for food or as pets, focusing on Batrachochytrium dendrobatidis (Bd), ranavirus and general clinical condition. Samples were collected from 2,389 individual animals at 51 sites in Lao PDR, Cambodia, Vietnam and Singapore for Bd screening, and 74 animals in Cambodia and Vietnam for ranavirus screening. Bd was found in one frog (n = 347) in Cambodia and 13 in Singapore (n = 419). No Bd was found in Lao PDR (n = 1,126) or Vietnam (n = 497), and no ranavirus was found in Cambodia (n = 70) or Vietnam (n = 4). Mild to severe dermatological lesions were observed in all East Asian bullfrogs Hoplobatrachus rugolosus (n = 497) sampled in farms in Vietnam. Histologic lesions consistent with sepsis were found within the lesions of three frogs and bacterial sepsis in two (n = 4); one had Gram-negative bacilli and one had acid-fast organisms consistent with mycobacterium sp. These results confirm that Bd is currently rare in amphibian trade in Southeast Asia. The presence of Mycobacterium-associated disease in farmed H. rugolosus is a cause for concern, as it may have public health implications and indicates the need for improved biosecurity in amphibian farming and trade.
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Affiliation(s)
- Martin Gilbert
- Wildlife Conservation Society, 2300 Southern Blvd, Bronx, NY 10460, USA.
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Differential viral propagation and induction of apoptosis by grouper iridovirus (GIV) in cell lines from three non-host species. Virus Res 2012; 167:16-25. [DOI: 10.1016/j.virusres.2012.03.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 03/20/2012] [Accepted: 03/21/2012] [Indexed: 02/08/2023]
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Garmyn A, Van Rooij P, Pasmans F, Hellebuyck T, Van Den Broeck W, Haesebrouck F, Martel A. Waterfowl: potential environmental reservoirs of the chytrid fungus Batrachochytrium dendrobatidis. PLoS One 2012; 7:e35038. [PMID: 22514705 PMCID: PMC3325947 DOI: 10.1371/journal.pone.0035038] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 03/12/2012] [Indexed: 11/18/2022] Open
Abstract
Infections with Batrachochytrium dendrobatidis (B. dendrobatidis), the causal agent of chytridiomycosis, have been shown to play an important role in the decline of amphibians worldwide. Spread of the fungus is poorly understood. Bird movement might possibly contribute to the spread of B. dendrobatidis in the environment. Therefore, 397 wild geese in Belgium were screened for presence of B. dendrobatidis on their toes using real-time quantitative PCR (qPCR). In addition, chemotaxis towards, adhesion, survival after desiccation and proliferation of B. dendrobatidis on keratinous toe scales from waterfowl were examined in vitro. qPCR revealed that 76 geese (15%) were positive for B. dendrobatidis. Results of the in vitro tests showed that B. dendrobatidis is attracted to the keratinous toes of aquatic birds on which they can adhere and even proliferate. However, desiccation is poorly tolerated. This suggests waterfowl are potential environmental reservoirs for B. dendrobatidis.
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Affiliation(s)
- An Garmyn
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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Peel AJ, Hartley M, Cunningham AA. Qualitative risk analysis of introducing Batrachochytrium dendrobatidis to the UK through the importation of live amphibians. DISEASES OF AQUATIC ORGANISMS 2012; 98:95-112. [PMID: 22436458 DOI: 10.3354/dao02424] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The international amphibian trade is implicated in the emergence and spread of the amphibian fungal disease chytridiomycosis, which has resulted in amphibian declines and extinctions globally. The establishment of the causal pathogen, Batrachochytrium dendrobatidis (Bd), in the UK could negatively affect the survival of native amphibian populations. In recognition of the ongoing threat that it poses to amphibians, Bd was recently included in the World Organisation for Animal Health Aquatic Animal Health Code, and therefore is in the list of international notifiable diseases. Using standardised risk analysis guidelines, we investigated the likelihood that Bd would be introduced to and become established in wild amphibians in the UK through the importation of live amphibians. We obtained data on the volume and origin of the amphibian trade entering the UK and detected Bd infection in amphibians being imported for the pet and private collection trade and also in amphibians already held in captive pet, laboratory and zoological collections. We found that current systems for recording amphibian trade into the UK underestimate the volume of non-European Union trade by almost 10-fold. We identified high likelihoods of entry, establishment and spread of Bd in the UK and the resulting major overall impact. Despite uncertainties, we determined that the overall risk estimation for the introduction of Bd to the UK through the importation of live amphibians is high and that risk management measures are required, whilst ensuring that negative effects on legal trade are minimised.
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Affiliation(s)
- Alison J Peel
- Institute of Zoology, Zoological Society of London, Regents Park, London NW1 4RY, UK.
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