The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Andrew Storfer - One of the best experts on this subject based on the ideXlab platform.
-
Comparative Genomics of an Emerging Amphibian Virus
Genetics Society of America, 2016Co-Authors: Brendan Epstein, Andrew StorferAbstract: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
-
Combined Effects of Virus, Pesticide, and Predator Cue on the Larval Tiger Salamander (Ambystoma Tigrinum)
EcoHealth, 2011Co-Authors: Jacob L. Kerby, Alison J. Hart, Andrew StorferAbstract:Emerging diseases and environmental contamination are two of the leading hypotheses for global amphibian declines. Yet few studies have examined the influence of contaminants on disease susceptibility, and even fewer have incorporated the role of natural stressors such as predation. We performed a factorial study investigating the interaction of the insecticide carbaryl, dragonfly predator cue, and the emerging pathogen Ambystoma Tigrinum Virus (ATV) on fitness correlates and disease susceptibility in tiger salamander larvae. Four week old larvae were exposed for 22 days in a 2 (0, 500 μg/l carbaryl) × 2 (control, predator cue water) × 2 (0, 1 × 10^4 pfu ATV) factorial designed laboratory study. Results show significant impacts to survival of larvae for both Virus and predator cue treatments, as well as an interactive effect between the two, in which predator cue strongly exacerbated disease-driven mortality. There was a clear pattern of reduced survival with the addition of stressors, with those where all three stressors were present exhibiting the worst effects (a decrease in survival from 93 to 60%). On those that survived, we also detected several sub-lethal impacts in mass, SVL, and development. Predator cue and pesticide treatments significantly reduced both SVL and mass. Virus and predator treatments significantly slowed development. Stressors also exhibited opposing effects on activity. Predator cue caused a significant reduction in activity, whereas Virus caused a significant increase in activity over time. These results highlight the importance of examining combined natural and introduced stressors to understand potential impacts on amphibian species. Such stressors may contribute to the emergence of ATV in particular regions, raising concerns about the influence of pesticides on disease emergence in general.
-
Combined Effects of Atrazine and Chlorpyrifos on Susceptibility of the Tiger Salamander to Ambystoma Tigrinum Virus
EcoHealth, 2009Co-Authors: Jacob L. Kerby, Andrew StorferAbstract:Several hypotheses have been examined as potential causes of global amphibian declines, including emerging infectious diseases and environmental contaminants. Although these factors are typically studied separately, animals are generally exposed to both stressors simultaneously. We examined the effects of the herbicide atrazine and the insecticide chlorpyrifos on the susceptibility of tiger salamander larvae, Ambystoma Tigrinum, to a viral pathogen, Ambystoma Tigrinum Virus (ATV). Environmentally relevant concentrations of atrazine (0, 20, 200 μg/L) and chlorpyrifos (0, 2, 20, 200 μg/L) were used along with ATV in a fully factorial experimental design whereby individually housed, 4-week-old larvae were exposed for 2 weeks. Atrazine alone was not lethal to larvae, and chlorpyrifos alone was lethal only at the highest concentration. When combined with ATV, chlorpyrifos increased susceptibility to viral infection and resulted in increased larval mortality. A significant interactive effect between atrazine and ATV was detected. Atrazine treatments slightly decreased survival in Virus-exposed treatments, yet slightly increased survival in the Virus-free treatments. These findings corroborate earlier research on the impacts of atrazine, in particular, on disease susceptibility, but exhibit greater effects (i.e., reduced survival) when younger larvae were examined. This study is the first of its kind to demonstrate decreases in amphibian survival with the combination of pesticide and a viral disease. Further examination of these multiple stressors can provide key insights into potential significance of environmental cofactors, such as pesticides, in disease dynamics.
-
transcriptional response of mexican axolotls to Ambystoma Tigrinum Virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV). At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity. Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridoVirus in adult Xenopus. We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoViruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.
-
Transcriptional response of Mexican axolotls to Ambystoma Tigrinum Virus (ATV) infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, S Randal VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls ( Ambystoma mexicanum ) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV). Result At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity. Conclusion Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridoVirus in adult Xenopus . We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoViruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.
James P Collins - One of the best experts on this subject based on the ideXlab platform.
-
mortality rates differ among amphibian populations exposed to three strains of a lethal ranaVirus
Ecohealth, 2009Co-Authors: Trent K Bollinger, Danna M Schock, James P CollinsAbstract:Infectious diseases are a growing threat to biodiversity, in many cases because of synergistic effects with habitat loss, environmental contamination, and climate change. Emergence of pathogens as new threats to host populations can also arise when novel combinations of hosts and pathogens are unintentionally brought together, for example, via commercial trade or wildlife relocations and reintroductions. Chytrid fungus (Batrachochytrium dendrobatidis) and amphibian ranaViruses (family Iridoviridae) are pathogens implicated in global amphibian declines. The emergence of disease associated with these pathogens appears to be at least partly related to recent translocations over large geographic distances. We experimentally examined the outcomes of novel combinations of host populations and pathogen strains using the amphibian ranaVirus Ambystoma Tigrinum Virus (ATV) and barred tiger salamanders (Ambystoma mavortium, formerly considered part of the Ambystoma Tigrinum complex). One salamander population was highly resistant to lethal infections by all ATV strains, including its own strain, and mortality rates differed among ATV strains according to salamander population. Mortality rates in novel pairings of salamander population and ATV strain were not predictable based on knowledge of mortality rates when salamander populations were exposed to their own ATV strain. The underlying cause(s) for the differences in mortality rates are unknown, but local selection pressures on salamanders, Viruses, or both, across the range of this widespread host–pathogen system are a plausible hypothesis. Our study highlights the need to minimize translocations of amphibian ranaViruses, even among conspecifc host populations, and the importance of considering intraspecific variation in endeavors to manage wildlife diseases.
-
spatial and temporal patterns of Ambystoma Tigrinum Virus atv prevalence in tiger salamanders Ambystoma Tigrinum nebulosum
Diseases of Aquatic Organisms, 2009Co-Authors: Jesse L. Brunner, Amy L. Greer, James P CollinsAbstract:Amphibian ranaViruses have been documented as causes of mass mortality in amphib- ian populations throughout the world. The temporal and spatial dynamics of ranaVirus infections when epidemics are not apparent remains unclear. To address this question, we collected tissue sam- ples from 2003 to 2006 in 4 geographically separated tiger salamander Ambystoma Tigrinum nebulo- sum host populations on the Kaibab Plateau in northern Arizona. We tested for Ambystoma Tigrinum Virus (ATV), a lethal ranaVirus of tiger salamanders, calculated ATV prevalence for each sampling date, and examined temporal and spatial patterns by quantifying the annual level of ATV synchrony among populations using the intraclass correlation coefficient. Salamander populations were com- monly infected with ATV. We observed no morbidity or mortality in these populations even as ATV prevalence values varied from 0 to 57%. Infection prevalence across the landscape was more similar within a given year than between years. There was no statistically significant spatial pattern in preva- lence across the landscape. Our findings highlight the need to explore new hypotheses regarding the population level impact of these pathogens on amphibian communities.
-
Transmission dynamics of the amphibian ranaVirus Ambystoma Tigrinum Virus.
Diseases of aquatic organisms, 2007Co-Authors: Jesse L. Brunner, Danna M Schock, James P CollinsAbstract:Transmission is central to pathogen fitness and strongly influences the impact of pathogens on host populations. Particularly important to transmission dynamics is the distinction between direct transmission requiring close physical contact (e.g. bumping, fighting, or coughing) and indirect transmission from environmental sources such as contaminated substrates. We present data from 4 experiments addressing the form, routes, and timing of transmission of Ambystoma Tigrinum Virus (ATV) among tiger salamanders Ambystoma Tigrinum nebulosum. Our data suggest that ATV is efficiently transmitted by direct interactions between live animals (bumping, biting and cannibalism) as well as by necrophagy and indirectly via water and fomites. Determining which form of transmission is most important in nature is essential for understanding transmission at the population level. Our experiments also revealed an important temporal aspect of infectiousness: larval salamanders become infectious soon after exposure to ATV and their propensity to infect others increases with time. These results begin to clarify the mechanisms and dynamics of ATV transmission and lead to key questions that need to be addressed in future research.
-
sensitivity of a diagnostic test for amphibian ranaVirus varies with sampling protocol
Journal of Wildlife Diseases, 2007Co-Authors: Amy L. Greer, James P CollinsAbstract:Field samples are commonly used to estimate disease prevalence in wild populations. Our confidence in these estimates requires understanding the sensitivity and specificity of the diagnostic tests. We assessed the sensitivity of the most commonly used diagnostic tests for amphibian RanaVirus by infecting salamanders (Ambystoma Tigrinum; Amphibia, Caudata) with Ambystoma Tigrinum Virus (ATV) and then sampling euthanized animals (whole animal) and noneuthanized animals (tail clip) at five time intervals after exposure. We used a standard polymerase chain reaction (PCR) protocol to screen for ATV. Agreement between test results from whole-animal and tail-clip samples increased with time postexposure. This indicates that the ability to identify infected animals increases following exposure, leading to a more accurate estimate of prevalence in a population. Our results indicate that tail-clip sampling can underestimate the true prevalence of ATV in wild amphibian populations.
-
Susceptibility of the Endangered California Tiger Salamander, Ambystoma californiense, to RanaVirus Infection
Journal of wildlife diseases, 2007Co-Authors: Angela M. Picco, Jesse L. Brunner, James P CollinsAbstract:Emerging infectious diseases are implicated in the declines and extinctions of amphibians worldwide. RanaViruses in the family Iridoviridae are a global concern and have caused amphibian die-offs in wild populations in North America, Europe, South America, and in commercial populations in Asia and South America. The movement of amphibians for bait, food, pets, and research provides a route for the introduction of ranaViruses into naive and potentially endangered species. In this report, we demonstrate that the California tiger salamander, Ambystoma californiense, is susceptible to Ambystoma Tigrinum Virus (ATV). This Virus has not been previously reported in California tiger salamander, but observed mortality in experimentally infected animals suggests that California tiger salamander populations could be adversely affected by an ATV introduction.
Randal S Voss - One of the best experts on this subject based on the ideXlab platform.
-
transcriptional response of mexican axolotls to Ambystoma Tigrinum Virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV). At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity. Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridoVirus in adult Xenopus. We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoViruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.
-
transcriptional response of mexican axolotls to Ambystoma Tigrinum Virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV).
-
BioMed Central
2008Co-Authors: Andrew Storfer, Jennifer D Cotter, Christopher K Beachy, Randal S Voss, Al VossAbstract:Transcriptional response of Mexican axolotls to Ambystoma Tigrinum Virus (ATV) infectio
Jennifer D Cotter - One of the best experts on this subject based on the ideXlab platform.
-
Transcriptional response of Mexican axolotls to Ambystoma Tigrinum Virus (ATV) infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, S Randal VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls ( Ambystoma mexicanum ) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV). Result At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity. Conclusion Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridoVirus in adult Xenopus . We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoViruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.
-
transcriptional response of mexican axolotls to Ambystoma Tigrinum Virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV). At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity. Although A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridoVirus in adult Xenopus. We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoViruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.
-
transcriptional response of mexican axolotls to Ambystoma Tigrinum Virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma Tigrinum Virus (ATV).
-
BioMed Central
2008Co-Authors: Andrew Storfer, Jennifer D Cotter, Christopher K Beachy, Randal S Voss, Al VossAbstract:Transcriptional response of Mexican axolotls to Ambystoma Tigrinum Virus (ATV) infectio
James K Jancovich - One of the best experts on this subject based on the ideXlab platform.
-
the Ambystoma Tigrinum Virus atv rnase iii gene can modulate host pkr activation and interferon production
Virology, 2017Co-Authors: Alexander G Allen, Scott Morgans, Eric Smith, Mariah M Aron, James K JancovichAbstract:Abstract The iridoVirus RNase III gene is one of 26 conserved core genes among the family Iridoviridae. Initial studies suggest this viral protein functions to suppress RNA interference pathways that may attack viral RNA during infection. Therefore, to determine if the Ambystoma Tigrinum Virus (ATV) RNase III-like gene (ORF 25R) can modulate the host innate immune response fish and human cells ectopically expressing 25R were treated with polyI:C and monitored for interferon synthesis and phosphorylation of eIF2α and PKR. We found a decrease in cellular IFN production and modulation of the PKR pathway. In addition, ATV deleted of the RNase III gene (ATVΔ25R) shows reduced pathogenicity in tiger salamanders. Collectively our data suggest that the ATV 25R protein is a pathogenesis factor that may function to help evade the host's immune response by masking activators of the IFN pathway.
-
Characterization of a PKR inhibitor from the pathogenic ranaVirus, Ambystoma Tigrinum Virus, using a heterologous vaccinia Virus system.
Virology, 2017Co-Authors: Trung Huynh, James K Jancovich, Latha Tripuraneni, Michael C. Heck, Jeffrey Langland, Bertram L JacobsAbstract: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.
-
innate immune evasion mediated by the Ambystoma Tigrinum Virus eukaryotic translation initiation factor 2α homologue
Journal of Virology, 2011Co-Authors: James K Jancovich, Bertram L JacobsAbstract:RanaViruses (family Iridoviridae, genus RanaVirus) are large, double-stranded DNA (dsDNA) Viruses whose replication is restricted to ectothermic vertebrates. Many highly pathogenic members of the genus RanaVirus encode a homologue of the eukaryotic translation initiation factor 2α (eIF2α). Data in a heterologous vaccinia Virus system suggest that the Ambystoma Tigrinum Virus (ATV) eIF2α homologue (vIF2αH; open reading frame [ORF] 57R) is involved in evading the host innate immune response by degrading the interferon-inducible, dsRNA-activated protein kinase, PKR. To test this hypothesis directly, the ATV vIF2αH gene (ORF 57R) was deleted by homologous recombination, and a selectable marker was inserted in its place. The ATVΔ57R Virus has a small plaque phenotype and is 8-fold more sensitive to interferon than wild-type ATV (wtATV). Infection of fish cells with the ATVΔ57R Virus leads to eIF2α phosphorylation, in contrast to infection with wtATV, which actively inhibits eIF2α phosphorylation. The inability of ATVΔ57R to prevent phosphorylation of eIF2α correlates with degradation of fish PKZ, an interferon-inducible enzyme that is closely related to mammalian PKR. In addition, salamanders infected with ATVΔ57R displayed an increased time to death compared to that of wtATV-infected salamanders. Therefore, in a biologically relevant system, the ATV vIF2αH gene acts as an innate immune evasion factor, thereby enhancing Virus pathogenesis.
-
genomic sequence of a ranaVirus family iridoviridae associated with salamander mortalities in north america
Virology, 2003Co-Authors: James K Jancovich, Elizabeth W. Davidson, Jinghe Mao, Gregory V Chinchar, Christopher Wyatt, Steven T Case, Sudhir Kumar, Graziela Valente, Sankar Subramanian, James P CollinsAbstract:Disease is among the suspected causes of amphibian population declines, and an iridoVirus and a chytrid fungus are the primary pathogens associated with amphibian mortalities. Ambystoma Tigrinum Virus (ATV) and a closely related strain, Regina ranaVirus (RRV), are implicated in salamander die-offs in Arizona and Canada, respectively. We report the complete sequence of the ATV genome and partial sequence of the RRV genome. Sequence analysis of the ATV/RRV genomes showed marked similarity to other ranaViruses, including tiger frog Virus (TFV) and frog Virus 3 (FV3), the type Virus of the genus RanaVirus (family Iridoviridae), as well as more distant relationships to lymphocystis disease Virus, Chilo iridescent Virus, and infectious spleen and kidney necrosis Virus. Putative open reading frames (ORFs) in the ATV sequence identified 24 genes that appear to control Virus replication and block antiviral responses. In addition, >50 other putative genes, homologous to ORFs in other iridoviral genomes but of unknown function, were also identified. Sequence comparison performed by dot plot analysis between ATV and itself revealed a conserved 14-bp palindromic repeat within most intragenic regions. Dot plot analysis of ATV vs RRV sequences identified several polymorphisms between the two isolates. Finally, a comparison of ATV and TFV genomic sequences identified genomic rearrangements consistent with the high recombination frequency of iridoViruses. Given the adverse effects that ranaVirus infections have on amphibian and fish populations, ATV/RRV sequence information will allow the design of better diagnostic probes for identifying ranaVirus infections and extend our understanding of molecular events in ranaVirus-infected cells.
-
Transmission of the Ambystoma Tigrinum Virus to alternative hosts.
Diseases of aquatic organisms, 2001Co-Authors: James K Jancovich, Elizabeth W. Davidson, Bertram L Jacobs, April Seiler, James P CollinsAbstract:Ambystoma Tigrinum Virus (ATV) is a lethal Virus originally isolated from Sonora tiger salamanders Ambystoma Tigrinum stebbinsi in the San Rafael Valley in southern Arizona. USA. ATV is implicated in several salamander epizootics. We attempted to transmit ATV experimentally to fish and amphibians by injection, water bath exposure, or feeding to test whether ATV can cause clinical signs of infection or be recovered from exposed individuals that do not show clinical signs. Cell culture and polymerase chain reaction of the viral major capsid protein gene were used for viral detection. Salamanders and newts became infected with ATV and the Virus was recovered from these animals, but Virus could not be recovered from any of the frogs or fish tested. These results suggest that ATV may only infect urodeles and that fish and frogs may not be susceptible to ATV infection.