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McEachran MC, Sampedro F, Travis DA, Phelps NBD. An expert-based risk ranking framework for assessing potential pathogens in the live baitfish trade. Transbound Emerg Dis 2020; 68:3463-3473. [PMID: 33295097 PMCID: PMC9290568 DOI: 10.1111/tbed.13951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/06/2020] [Accepted: 10/30/2020] [Indexed: 11/28/2022]
Abstract
As global trade of live animals expands, there is increasing need to assess the risks of invasive organisms, including pathogens, that can accompany these translocations. The movement and release of live baitfish by recreational anglers has been identified as a particularly high‐risk pathway for the spread of aquatic diseases in the United States. To provide risk‐based decision support for preventing and managing disease invasions from baitfish release, we developed a hazard identification and ranking tool to identify the pathogens that pose the highest risk to wild fish via this pathway. We created a screening protocol and semi‐quantitative stochastic risk ranking framework, combining published data with expert elicitation (n = 25) and applied the framework to identify high‐priority pathogens for the bait supply in Minnesota, USA. Normalized scores were developed for seven risk criteria (likelihood of transfer, prevalence in bait supply, likelihood of colonization, current distribution, economic impact if established, ecological impact if established and host species) to characterize a pathogen's ability to persist in the bait supply and cause impacts to wild fish species of concern. The generalist macroparasite Schizocotyle acheilognathi was identified as presenting highest overall threat, followed by the microsporidian Ovipleistophora ovariae, and viral haemorrhagic septicaemia virus. Our findings provide risk‐based decision support for managers charged with maintaining both the recreational fishing industry and sustainable, healthy natural resources. Particularly, the identification of several high‐risk but currently unregulated pathogens suggests that focusing risk management on pathogens of concern in all potential host species could reduce disease introduction risk. The ranking process, implemented here for a single state case study, provides a conceptual framework for integrating expert opinion and sparse available data that could be scaled up and applied across jurisdictions to inform risk‐based management of the live baitfish pathway.
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Affiliation(s)
- Margaret C McEachran
- Minnesota Aquatic Invasive Species Research Center, University of Minnesota, St. Paul, MN, USA.,Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN, USA
| | - Fernando Sampedro
- Environmental Health Sciences Division, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Dominic A Travis
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN, USA.,One Health Division, Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - Nicholas B D Phelps
- Minnesota Aquatic Invasive Species Research Center, University of Minnesota, St. Paul, MN, USA.,Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN, USA
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2
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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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3
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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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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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Use of cell lines and primary cultures to explore the capacity of rainbow trout to be a host for frog virus 3 (FV3). In Vitro Cell Dev Biol Anim 2015; 51:894-904. [PMID: 25948044 DOI: 10.1007/s11626-015-9911-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/03/2015] [Indexed: 12/11/2022]
Abstract
The capacity of rainbow trout, Oncorhynchus mykiss, to be a host for frog virus 3 (FV3) was evaluated at the cellular level. Cell cultures from this species were tested for their ability to express FV3 major capsid protein (MCP) gene, to develop cytopathic effect (CPE), and to produce FV3. After FV3 addition, MCP transcripts were detected in six of six cell lines and in primary macrophage cultures. CPE developed in all cell culture systems, except primary lymphocytes. For the macrophage cell line, RTS11, and primary macrophages, cell death was by apoptosis because DNA laddering and Annexin staining were detected. By contrast, markers of apoptosis did not accompany CPE in three epithelial cell lines from the gill (RTgill-W1), intestine (RTgut-GC), and liver (RTL-W1) and in two fibroblast cell lines from gonads (RTG-2) and skin (RTHDF). Therefore, FV3 was able to enter and begin replicating in several cell types. Yet, FV3 was produced in only two cell lines, RTG-2 and RTL-W1, and only modestly. Overall, these results suggest that if tissue accessibility were possible, FV3 would have the capacity to induce injury, but the ability to replicate would be limited, likely making rainbow trout a poor host for FV3.
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Brenes R, Miller DL, Waltzek TB, Wilkes RP, Tucker JL, Chaney JC, Hardman RH, Brand MD, Huether RR, Gray MJ. Susceptibility of fish and turtles to three ranaviruses isolated from different ectothermic vertebrate classes. JOURNAL OF AQUATIC ANIMAL HEALTH 2014; 26:118-126. [PMID: 24895866 DOI: 10.1080/08997659.2014.886637] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ranaviruses have been associated with mortality of lower vertebrates around the world. Frog virus 3 (FV3)-like ranaviruses have been isolated from different ectothermic vertebrate classes; however, few studies have demonstrated whether this pathogen can be transmitted among classes. Using FV3-like ranaviruses isolated from the American bullfrog Lithobates catesbeianus, eastern box turtle Terrapene carolina carolina, and Pallid Sturgeon Scaphirhynchus albus, we tested for the occurrence of interclass transmission (i.e., infection) and host susceptibility (i.e., percent mortality) for five juvenile fish and three juvenile turtle species exposed to each of these isolates. Exposure was administered via water bath (10(3) PFU/mL) for 3 d and survival was monitored for 28 d. Florida softshell turtles Apalone ferox experienced no mortality, but 10% and 20% of individuals became infected by the turtle and fish isolate, respectively. Similarly, 5% of Mississippi map turtles Graptemys pseudogeographica kohni were subclinically infected with the turtle isolate at the end of the experiment. Channel Catfish Ictalurus punctatus experienced 5% mortality when exposed to the turtle isolate, while Western Mosquitofish Gambusia affinis experienced 10% mortality when exposed to the turtle and amphibian isolates and 5% mortality when exposed to the fish isolate. Our results demonstrated that interclass transmission of FV3-like ranaviruses is possible. Although substantial mortality did not occur in our experiments, the occurrence of low mortality and subclinical infections suggest that fish and aquatic turtles may function as reservoirs for FV3-like ranaviruses. Additionally, our study is the first to report transmission of FV3-like ranaviruses between fish and chelonians.
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Affiliation(s)
- Roberto Brenes
- a Department of Biology , Carroll University , 100 North East Avenue, Waukesha , Wisconsin 53186 , USA
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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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Transmission of ranavirus between ectothermic vertebrate hosts. PLoS One 2014; 9:e92476. [PMID: 24667325 PMCID: PMC3965414 DOI: 10.1371/journal.pone.0092476] [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: 01/25/2014] [Accepted: 02/22/2014] [Indexed: 11/22/2022] Open
Abstract
Transmission is an essential process that contributes to the survival of pathogens. Ranaviruses are known to infect different classes of lower vertebrates including amphibians, fishes and reptiles. Differences in the likelihood of infection among ectothermic vertebrate hosts could explain the successful yearlong persistence of ranaviruses in aquatic environments. The goal of this study was to determine if transmission of a Frog Virus 3 (FV3)-like ranavirus was possible among three species from different ectothermic vertebrate classes: Cope’s gray treefrog (Hyla chrysoscelis) larvae, mosquito fish (Gambusia affinis), and red-eared slider (Trachemys scripta elegans). We housed individuals previously exposed to the FV3-like ranavirus with naïve (unexposed) individuals in containers divided by plastic mesh screen to permit water flow between subjects. Our results showed that infected gray treefrog larvae were capable of transmitting ranavirus to naïve larval conspecifics and turtles (60% and 30% infection, respectively), but not to fish. Also, infected turtles and fish transmitted ranavirus to 50% and 10% of the naïve gray treefrog larvae, respectively. Nearly all infected amphibians experienced mortality, whereas infected turtles and fish did not die. Our results demonstrate that ranavirus can be transmitted through water among ectothermic vertebrate classes, which has not been reported previously. Moreover, fish and reptiles might serve as reservoirs for ranavirus given their ability to live with subclinical infections. Subclinical infections of ranavirus in fish and aquatic turtles could contribute to the pathogen’s persistence, especially when highly susceptible hosts like amphibians are absent as a result of seasonal fluctuations in relative abundance.
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Evidence of Ranavirus Infections among Sympatric Larval Amphibians and Box Turtles. J HERPETOL 2014. [DOI: 10.1670/12-235] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Storfer A, Mech SG, Reudink MW, Lew K. Inbreeding and strong population subdivision in an endangered salamander. CONSERV GENET 2013. [DOI: 10.1007/s10592-013-0526-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Lei XY, Ou T, Zhu RL, Zhang QY. Sequencing and analysis of the complete genome of Rana grylio virus (RGV). Arch Virol 2012; 157:1559-64. [DOI: 10.1007/s00705-012-1316-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 03/19/2012] [Indexed: 12/29/2022]
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12
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Hoverman JT, Gray MJ, Miller DL, Haislip NA. Widespread occurrence of ranavirus in pond-breeding amphibian populations. ECOHEALTH 2012; 9:36-48. [PMID: 22173292 DOI: 10.1007/s10393-011-0731-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 10/30/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
Ranaviruses are an emerging threat for many amphibian populations, yet their distribution in amphibian communities and the association of infection with possible stressors and species is not fully understood due to historically sparse surveillance. Agricultural practices that reduce the water quality of amphibian breeding habitats (e.g., cattle access to wetlands) and environmental stressors (e.g., lower temperatures) may contribute to ranavirus emergence. We tested larval amphibians for ranavirus infection across four seasons in farm ponds (n = 40) located in Tennessee, USA. Cattle at various densities were allowed access to half of the sampled ponds. Ranavirus infections were detected in nine species and in 33 of the sampled ponds (83%), illustrating widespread occurrence of the pathogen. Species within the family Ranidae were the most frequently infected. In 13 of the ponds containing infected individuals, prevalence exceeded 40% during at least one season. Infections were detected in multiple seasons in 20 of the sampled ponds containing infections, suggesting that ranaviruses are relatively persistent in these systems. Cattle had negative effects on water quality (turbidity and ammonia) and there was a positive association between cattle abundance and ranavirus prevalence in the summer. Counter to previous field studies in North America, we found a significant positive association between water temperature and ranavirus prevalence in the fall sampling events. Despite these findings, the influences of cattle and temperature on ranavirus prevalence were not consistent across seasons. As such, the mechanisms driving high ranavirus prevalence across the landscape and over time remain unclear. Given the widespread occurrence of ranaviruses in wild amphibians, we encourage the implementation of surveillance programs to help identify potential drivers of emergence. Sites with high ranavirus prevalence should be monitored annually for outbreaks, and the long-term effects on population size determined.
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Affiliation(s)
- Jason T Hoverman
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
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Ecopathology of ranaviruses infecting amphibians. Viruses 2011; 3:2351-2373. [PMID: 22163349 PMCID: PMC3230856 DOI: 10.3390/v3112351] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/03/2011] [Accepted: 11/10/2011] [Indexed: 12/19/2022] Open
Abstract
Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry) contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease) than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs.
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