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Polly Roy - One of the best experts on this subject based on the ideXlab platform.
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Bluetongue Virus capsid protein vp5 perforates membranes at low endosomal ph during viral entry
Nature microbiology, 2021Co-Authors: Xian Xia, Polly Roy, Yanxiang Cui, Hong Z ZhouAbstract:Bluetongue Virus (BTV) is a non-enveloped Virus and causes substantial morbidity and mortality in ruminants such as sheep. Fashioning a receptor-binding protein (VP2) and a membrane penetration protein (VP5) on the surface, BTV releases its genome-containing core (VP3 and VP7) into the host cell cytosol after perforation of the endosomal membrane. Unlike enveloped ones, the entry mechanisms of non-enveloped Viruses into host cells remain poorly understood. Here we applied single-particle cryo-electron microscopy, cryo-electron tomography and structure-guided functional assays to characterize intermediate states of BTV cell entry in endosomes. Four structures of BTV at the resolution range of 3.4–3.9 A show the different stages of structural rearrangement of capsid proteins on exposure to low pH, including conformational changes of VP5, stepwise detachment of VP2 and a small shift of VP7. In detail, sensing of the low-pH condition by the VP5 anchor domain triggers three major VP5 actions: projecting the hidden dagger domain, converting a surface loop to a protonated β-hairpin that anchors VP5 to the core and stepwise refolding of the unfurling domains into a six-helix stalk. Cryo-electron tomography structures of BTV interacting with liposomes show a length decrease of the VP5 stalk from 19.5 to 15.5 nm after its insertion into the membrane. Our structures, functional assays and structure-guided mutagenesis experiments combined indicate that this stalk, along with dagger domain and the WHXL motif, creates a single pore through the endosomal membrane that enables the viral core to enter the cytosol. Our study unveils the detailed mechanisms of BTV membrane penetration and showcases general methods to study cell entry of other non-enveloped Viruses. Cryo-electron microscopy and cryo-electron tomography reveal conformational changes of the Bluetongue Virus capsid protein VP5 that lead to membrane perforation and Virus release into the cytosol.
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Bluetongue Virus structure and assembly
Current Opinion in Virology, 2017Co-Authors: Polly RoyAbstract:Bluetongue Virus (BTV) is an insect-vectored emerging pathogen of wild ruminants and livestock in many parts of the world. The virion particle is a complex structure of consecutive layers of protein surrounding a genome of ten double-stranded (ds) RNA segments. BTV has been studied as a model system for large, non-enveloped dsRNA Viruses. Several new techniques have been applied to define the Virus-encoded enzymes required for RNA replication to provide an order for the assembly of the capsid shell and the protein sequestration required for it. Further, a reconstituted in vitro system has defined the individual steps of the assembly and packaging of the genomic RNA. These findings illuminate BTV assembly and indicate the pathways that related Viruses might use to provide an informed starting point for intervention or prevention.
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Bluetongue Virus Capsid Assembly and Maturation
MDPI AG, 2014Co-Authors: Bjorn-patrick Mohl, Polly RoyAbstract:Maturation is an intrinsic phase of the viral life cycle and is often intertwined with egress. In this review we focus on orbiVirus maturation by using Bluetongue Virus (BTV) as a representative. BTV, a member of the genus OrbiVirus within the family Reoviridae, has over the last three decades been subjected to intense molecular study and is thus one of the best understood Viruses. BTV is a non-enveloped Virus comprised of two concentric protein shells that encapsidate 10 double-stranded RNA genome segments. Upon cell entry, the outer capsid is shed, releasing the core which does not disassemble into the cytoplasm. The polymerase complex within the core then synthesizes transcripts from each genome segment and extrudes these into the cytoplasm where they act as templates for protein synthesis. Newly synthesized ssRNA then associates with the replicase complex prior to encapsidation by inner and outer protein layers of core within Virus-triggered inclusion bodies. Maturation of core occurs outside these inclusion bodies (IBs) via the addition of the outer capsid proteins, which appears to be coupled to a non-lytic, exocytic pathway during early infection. Similar to the enveloped Viruses, BTV hijacks the exocytosis and endosomal sorting complex required for trafficking (ESCRT) pathway via a non-structural glycoprotein. This exquisitely detailed understanding is assembled from a broad array of assays, spanning numerous and diverse in vitro and in vivo studies. Presented here are the detailed insights of BTV maturation and egress
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Interactions between the Inner and Outer Capsids of Bluetongue Virus
2013Co-Authors: Emma L. Nason, Mario Forzan, Rosalba Rothagel, Sharmila K. Mukherjee, Alak Kanti Kar, B. Venkataram V. Prasad, Polly RoyAbstract:Bluetongue Virus is a large and structurally complex Virus composed of three concentric capsid layers that surround 10 segments of a double-stranded RNA genome. X-ray crystallographic analysis of the particles without the outer capsid layer has provided atomic structural details of VP3 and VP7, which form the inner two layers. However, limited structural information is available on the other five proteins in the virion—two of which are important for receptor recognition, hemagglutination, and membrane interaction—are in the outer layer, and the others, important for endogenous transcriptase activity are internal. Here we report the electron cryomicroscopy (cryo-EM) reconstruction of the mature particle, which shows that the outer layer has a unique non-T � 13 icosahedral organization consisting of two distinct triskelion and globular motifs interacting extensively with the underlying T � 13 layer. Comparative cryo-EM analysis of the recombinant corelike particles has shown that VP1 (viral polymerase) and VP4 (capping enzyme) together form a flower-shaped structure attached to the underside of VP3, directly beneath the fivefold axis. The structural data have been substantiated by biochemical studies demonstrating the interactions between the individual outer and inner capsid proteins. Bluetongue Virus (BTV) is an economically important member of the OrbiVirus genus in the family Reoviridae. This is
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role of cellular caspases nuclear factor kappa b and interferon regulatory factors in Bluetongue Virus infection and cell fate
Virology Journal, 2010Co-Authors: Meredith Stewart, Polly RoyAbstract:Background Bluetongue Virus (BTV) infection causes haemorrhagic disease in ruminants and induces cell death. The pathogenesis in animals and in cell culture has been linked to BTV-induced apoptosis.
Peter P C Mertens - One of the best experts on this subject based on the ideXlab platform.
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genome sequence of Bluetongue Virus serotype 17 isolated in brazil in 2014
Genome Announcements, 2016Co-Authors: Ana Carolina Diniz Matos, Kyriaki Nomikou, Julio Cesar Câmara Rosa, Lorena Lima Barbosa Guimaraes, Erica Azevedo Costa, Maria Isabel Maldonado Coelho Guedes, David Driemeier, Zelia Ines Portela Lobato, Peter P C MertensAbstract:The complete genome sequence of Bluetongue Virus (BTV) serotype 17 strain 17/BRA/2014/73, isolated from a sheep in Brazil in 2014, is reported here. All segments clustered with western topotype strains and indicated reassortment events with other BTV from the Americas. The strain 17/BRA/2014/73 represents a novel reference strain for BTV-17 from South America.
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Virus and host factors affecting the clinical outcome of Bluetongue Virus infection
Journal of Virology, 2014Co-Authors: Marco Caporale, Andrew E Shaw, Peter P C Mertens, Giovanni Savini, Piet A. Van Rijn, Luigina Di Gialleonorado, Anna Janowicz, Gavin S Wilkie, Mauro Di VenturaAbstract:ABSTRACT Bluetongue is a major infectious disease of ruminants caused by Bluetongue Virus (BTV), an arboVirus transmitted by Culicoides. Here, we assessed Virus and host factors influencing the clinical outcome of BTV infection using a single experimental framework. We investigated how mammalian host species, breed, age, BTV serotypes, and strains within a serotype affect the clinical course of Bluetongue. Results obtained indicate that in small ruminants, there is a marked difference in the susceptibility to clinical disease induced by BTV at the host species level but less so at the breed level. No major differences in virulence were found between divergent serotypes (BTV-8 and BTV-2). However, we observed striking differences in virulence between closely related strains of the same serotype collected toward the beginning and the end of the European BTV-8 outbreak. As observed previously, differences in disease severity were also observed when animals were infected with either blood from a BTV-infected animal or from the same Virus isolated in cell culture. Interestingly, with the exception of two silent mutations, full viral genome sequencing showed identical consensus sequences of the Virus before and after cell culture isolation. However, deep sequencing analysis revealed a marked decrease in the genetic diversity of the viral population after passaging in mammalian cells. In contrast, passaging in Culicoides cells increased the overall number of low-frequency variants compared to Virus never passaged in cell culture. Thus, Culicoides might be a source of new viral variants, and viral population diversity can be another factor influencing BTV virulence. IMPORTANCE Bluetongue is one of the major infectious diseases of ruminants. It is caused by an arboVirus known as Bluetongue Virus (BTV). The clinical outcome of BTV infection is extremely variable. We show that there are clear links between the severity of Bluetongue and the mammalian host species infected, while at the breed level differences were less evident. No differences were observed in the virulence of two different BTV serotypes (BTV-8 and BTV-2). In contrast, we show that the European BTV-8 strain isolated at the beginning of the Bluetongue outbreak in 2006 was more virulent than a strain isolated toward the end of the outbreak. In addition, we show that there is a link between the variability of the BTV population as a whole and virulence, and our data also suggest that Culicoides cells might function as an “incubator” of viral variants.
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Complete Genome Characterisation of a Novel 26th Bluetongue Virus Serotype from Kuwait
2013Co-Authors: Sushila Maan, Eva Veronesi, Narender S. Maan, Kyriaki Nomikou, Manjunatha N. Belaganahalli, Houssam Attoui, Katarzyna Bachanek-bankowska, Peter P C MertensAbstract:Bluetongue Virus is the ‘‘type’ ’ species of the genus OrbiVirus, family Reoviridae. Twenty four distinct Bluetongue Virus (BTV) serotypes have been recognized for decades, any of which is thought to be capable of causing ‘‘Bluetongue’ ’ (BT), an insectborne disease of ruminants. However, two further BTV serotypes, BTV-25 (Toggenburg orbiVirus, from Switzerland) and BTV-26 (from Kuwait) have recently been identified in goats and sheep, respectively. The BTV genome is composed of ten segments of linear dsRNA, encoding 7 Virus-structural proteins (VP1 to VP7) and four distinct non-structural (NS) proteins (NS1 to NS4). We report the entire BTV-26 genome sequence (isolate KUW2010/02) and comparisons to other orbiViruses. Highest identity levels were consistently detected with other BTV strains, identifying KUW2010/02 as BTV. The outer-core protein and major BTV serogroup-specific antigen ‘‘VP7’ ’ showed 98 % aa sequence identity with BTV-25, indicating a common ancestry. However, higher level of variation in the nucleotide sequence of Seg-7 (81.2 % identity) suggests strong conservation pressures on the protein of these two strains, and that they diverged a long time ago. Comparisons of Seg-2, encoding major outer-capsid component and cell-attachment protein ‘‘VP2’ ’ identified KUW2010/02 as 26th BTV, within a 12th Seg-2 nucleotype [nucleotype L]. Comparisons of Seg-6, encoding the smaller outer capsid protein VP5, also showed levels of nt/aa variation consistent with identification of KUW2010/02 as BTV-26 (within a 9th Seg-6 nucleotype- nucleotype I). Sequence data for Seg-2 of KUW2010/02 were used to design four sets of oligonucleotide primers for use in BTV-26, type-specific RT-PCR assays
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complete genome characterisation of a novel 26th Bluetongue Virus serotype from kuwait
PLOS ONE, 2011Co-Authors: Sushila Maan, Eva Veronesi, Narender S. Maan, Kyriaki Nomikou, Manjunatha N. Belaganahalli, Houssam Attoui, Katarzyna Bachanekbankowska, Peter P C MertensAbstract:Bluetongue Virus is the “type” species of the genus OrbiVirus, family Reoviridae. Twenty four distinct Bluetongue Virus (BTV) serotypes have been recognized for decades, any of which is thought to be capable of causing “Bluetongue” (BT), an insect-borne disease of ruminants. However, two further BTV serotypes, BTV-25 (Toggenburg orbiVirus, from Switzerland) and BTV-26 (from Kuwait) have recently been identified in goats and sheep, respectively. The BTV genome is composed of ten segments of linear dsRNA, encoding 7 Virus-structural proteins (VP1 to VP7) and four distinct non-structural (NS) proteins (NS1 to NS4). We report the entire BTV-26 genome sequence (isolate KUW2010/02) and comparisons to other orbiViruses. Highest identity levels were consistently detected with other BTV strains, identifying KUW2010/02 as BTV. The outer-core protein and major BTV serogroup-specific antigen “VP7” showed 98% aa sequence identity with BTV-25, indicating a common ancestry. However, higher level of variation in the nucleotide sequence of Seg-7 (81.2% identity) suggests strong conservation pressures on the protein of these two strains, and that they diverged a long time ago. Comparisons of Seg-2, encoding major outer-capsid component and cell-attachment protein “VP2” identified KUW2010/02 as 26th BTV, within a 12th Seg-2 nucleotype [nucleotype L]. Comparisons of Seg-6, encoding the smaller outer capsid protein VP5, also showed levels of nt/aa variation consistent with identification of KUW2010/02 as BTV-26 (within a 9th Seg-6 nucleotype - nucleotype I). Sequence data for Seg-2 of KUW2010/02 were used to design four sets of oligonucleotide primers for use in BTV-26, type-specific RT-PCR assays. Analyses of other more conserved genome segments placed KUW2010/02 and BTV-25/SWI2008/01 closer to each other than to other “eastern” or “western” BTV strains, but as representatives of two novel and distinct geographic groups (topotypes). Our analyses indicate that all of the BTV genome segments have evolved under strong purifying selection.
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expression and secretion of Bluetongue Virus serotype 8 btv 8 vp2 outer capsid protein by mammalian cells
Journal of Virological Methods, 2010Co-Authors: Antonio Capocefalo, Peter P C Mertens, Valentina Franceschi, Javier Castilloolivares, Sandro Cavirani, E Di Lonardo, Z Leni, Gaetano DonofrioAbstract:VP2 is the outermost Bluetongue Virus (BTV) antigenic protein, forming triskelion motifs on the virion surface. Although VP2 has been expressed successfully through many systems, its paracrine expression as a soluble form by mammalian cells represents a difficult task. In the present paper two fragments of VP2 have been expressed successfully into the medium of transiently transfected mammalian cells through a fusion peptides strategy. The crude conditioned medium containing the secreted peptide could be employed for immunodiagnostic assay development or vaccine purposes.
Martin Beer - One of the best experts on this subject based on the ideXlab platform.
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characterization of Bluetongue Virus serotype 28
Transboundary and Emerging Diseases, 2020Co-Authors: Velizar Bumbarov, Maria Jenckel, Martin Beer, Natalia Golender, E Khinich, Kerstin Wernike, Olga Zalesky, Oran ErsterAbstract:Bluetongue Virus (Reoviridae; OrbiVirus, BTV), which is usually transmitted by biting midges, affects wild and domestic ruminants worldwide, thereby causing an economically important disease. Recently, a putative new BTV strain was isolated from contaminated vaccine batches. In this study, we investigated the genomic and clinical characteristics of this isolate, provisionally designated BTV-28. Phylogenetic analysis of BTV-28 segment 2 (Seg-2) showed that it is related to Seg-2 from BTV serotypes 4, 10, 11, 17, 20 and 24, sharing 64%-66% identity in nucleotide sequences (nt) and 59%-62% in amino acid (aa) sequences of BTV VP2. BTV-28 Seg-6 is related to the newly reported XJ1407 BTV isolate, sharing 76.70% nt and 90.87% aa sequence identity. Seg-5 was most closely related to a South African BTV-4 strain, and all other segments showed close similarity to BTV-26. Experimental infection by injection of 6-month-old ewes caused clinical signs in all injected animals, lasting from 2 to 3 days to several weeks post-infection, including high body temperature, conjunctivitis, nasal discharge and rhinitis, facial oedema, oral hyperaemia, coronitis, cough, depression and tongue cyanosis. Naive control animals, placed together with the infected sheep, displayed clinical signs and were positive for viral RNA, but their acute disease phase was shorter than that of BTV-injected ewes. Control animals that were kept in a separated pen did not display any clinical signs and were negative for viral RNA presence throughout the experiment. Seroconversion was observed in the injected and in one of the two contact-infected animals. These findings demonstrate that BTV-28 infection of sheep can result in clinical manifestation, and the clinical signs detected in the contact animals suggest that it might be directly transmitted between the mammalian hosts.
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complete coding genome sequence of putative novel Bluetongue Virus serotype 27
Genome Announcements, 2015Co-Authors: Maria Jenckel, Cyril Viarouge, Emmanuel Bréard, Corinne Sailleau, Bernd Hoffmann, Martin Beer, Claudia Schulz, Dirk Hoper, Stéphan ZientaraAbstract:We announce the complete coding genome sequence of a novel Bluetongue Virus (BTV) serotype (BTV-n = putative BTV-27) detected in goats in Corsica, France, in 2014. Sequence analysis confirmed the closest relationship between sequences of the novel BTV serotype and BTV-25 and BTV-26, recently discovered in Switzerland and Kuwait, respectively.
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Bluetongue Virus
2013Co-Authors: Bernd Hoffmann, Michael Saßerath, Sabine Thalheim, Claudia Bunzenthal, Günter Strebelow, Martin BeerAbstract:Reemerging Bluetongue Virus serotype 8 (BTV-8) in Germany was detected fi rst in May 2007 in a sentinel cow and in February 2008 in an export heifer. Reemergence was confi rmed by retesting the samples, experimental inoculation, fi ngerprinting analysis, and Virus isolation. Overwintering of BTV-8 and continuous low-level infections are assumed. Bluetongue Virus (BTV) is a double-stranded RNA Virus of the genus OrbiVirus. BTV is transmitted to its hosts by the bite of Culicoides spp. midges. It causes a noncontagious, arthropod-borne disease of domestic and wild ruminants and camelids (1); disease can be serious, particularly in sheep (2–4). BTV had never been reported in any European country north of the Alps until August 2006, when outbreaks of BTV serotype 8 (BTV-8) were almost simultaneously discovered in the Netherlands, Belgium, Germany, and France (5–7). In 2006, a total of 893 cases were detected in Germany, but the source of initial Virus introduction remains unknown. Subsequently, BTV-8 overwintered in the region, spread over most of the country, and led to almost 21,000 new cases in 2007 in Germany. BTV-8 infections spread to additional European countries, e.g., the United Kingdom, Switzerland, the Czech Republic
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monitoring of putative vectors of Bluetongue Virus serotype 8 germany
Emerging Infectious Diseases, 2009Co-Authors: Bernd Hoffmann, Martin Beer, Burkhard Bauer, C Bauer, Hans Joachim Batza, Peterhenning Clausen, Martin Geier, Jorn Gethmann, Ellen Kiel, Gabriele LiebischAbstract:To identify the vectors of Bluetongue Virus (BTV) in Germany, we monitored Culicoides spp. biting midges during April 2007–May 2008. Molecular characterization of batches of midges that tested positive for BTV suggests C. obsoletus sensu stricto as a relevant vector of Bluetongue disease in central Europe.
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efficacy of three inactivated vaccines against Bluetongue Virus serotype 8 in sheep
Vaccine, 2009Co-Authors: Michael Eschbaumer, Bernd Hoffmann, Jorn Gethmann, Franz Josef Conraths, Thomas C Mettenleiter, Patricia Konig, Jens Peter Teifke, Carolina Probst, Martin BeerAbstract:Bluetongue has become a major animal health issue in the European Union. The member states and Switzerland have agreed on a vaccination strategy. Three different inactivated monovalent vaccines against Bluetongue Virus serotype 8 were selected for the compulsory vaccination program carried out in Germany in 2008. The efficacy of these vaccines was evaluated in a pilot study in sheep immunised under field conditions by clinical, virological and serological examination before and after experimental challenge infection with a BTV-8 field isolate. Antibody levels prior to challenge infection differed between the vaccinated groups, but all seroconverted animals were fully protected against clinical disease and Virus replication. Only one vaccinated animal was very weakly positive in the real-time RT-PCR at day 10 after challenge infection, and one seronegative sheep in one of the vaccine groups was not protected.
Bernd Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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complete coding genome sequence of putative novel Bluetongue Virus serotype 27
Genome Announcements, 2015Co-Authors: Maria Jenckel, Cyril Viarouge, Emmanuel Bréard, Corinne Sailleau, Bernd Hoffmann, Martin Beer, Claudia Schulz, Dirk Hoper, Stéphan ZientaraAbstract:We announce the complete coding genome sequence of a novel Bluetongue Virus (BTV) serotype (BTV-n = putative BTV-27) detected in goats in Corsica, France, in 2014. Sequence analysis confirmed the closest relationship between sequences of the novel BTV serotype and BTV-25 and BTV-26, recently discovered in Switzerland and Kuwait, respectively.
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Novel Bluetongue Virus in goats, Corsica, France, 2014
Emerging Infectious Diseases, 2014Co-Authors: Stéphan Zientara, Dirck H??per, Maria Jenckel, Cyril Viarouge, Corinne Sailleau, Labib Bakkali-kassimi, Aurore Romey, Bernd Hoffmann, Aurore FabletAbstract:During 2000-2013, 4 genotypes of Bluetongue Virus (BTV) were detected in Corsica, France. At the end of 2013, a compulsory BTV-1 vaccination campaign was initiated among domestic ruminants; biological samples from goats were tested as part of a corresponding monitoring program. A BTV strain with nucleotide sequences suggestive of a novel serotype was detected.
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Bluetongue Virus
2013Co-Authors: Bernd Hoffmann, Michael Saßerath, Sabine Thalheim, Claudia Bunzenthal, Günter Strebelow, Martin BeerAbstract:Reemerging Bluetongue Virus serotype 8 (BTV-8) in Germany was detected fi rst in May 2007 in a sentinel cow and in February 2008 in an export heifer. Reemergence was confi rmed by retesting the samples, experimental inoculation, fi ngerprinting analysis, and Virus isolation. Overwintering of BTV-8 and continuous low-level infections are assumed. Bluetongue Virus (BTV) is a double-stranded RNA Virus of the genus OrbiVirus. BTV is transmitted to its hosts by the bite of Culicoides spp. midges. It causes a noncontagious, arthropod-borne disease of domestic and wild ruminants and camelids (1); disease can be serious, particularly in sheep (2–4). BTV had never been reported in any European country north of the Alps until August 2006, when outbreaks of BTV serotype 8 (BTV-8) were almost simultaneously discovered in the Netherlands, Belgium, Germany, and France (5–7). In 2006, a total of 893 cases were detected in Germany, but the source of initial Virus introduction remains unknown. Subsequently, BTV-8 overwintered in the region, spread over most of the country, and led to almost 21,000 new cases in 2007 in Germany. BTV-8 infections spread to additional European countries, e.g., the United Kingdom, Switzerland, the Czech Republic
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monitoring of putative vectors of Bluetongue Virus serotype 8 germany
Emerging Infectious Diseases, 2009Co-Authors: Bernd Hoffmann, Martin Beer, Burkhard Bauer, C Bauer, Hans Joachim Batza, Peterhenning Clausen, Martin Geier, Jorn Gethmann, Ellen Kiel, Gabriele LiebischAbstract:To identify the vectors of Bluetongue Virus (BTV) in Germany, we monitored Culicoides spp. biting midges during April 2007–May 2008. Molecular characterization of batches of midges that tested positive for BTV suggests C. obsoletus sensu stricto as a relevant vector of Bluetongue disease in central Europe.
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efficacy of three inactivated vaccines against Bluetongue Virus serotype 8 in sheep
Vaccine, 2009Co-Authors: Michael Eschbaumer, Bernd Hoffmann, Jorn Gethmann, Franz Josef Conraths, Thomas C Mettenleiter, Patricia Konig, Jens Peter Teifke, Carolina Probst, Martin BeerAbstract:Bluetongue has become a major animal health issue in the European Union. The member states and Switzerland have agreed on a vaccination strategy. Three different inactivated monovalent vaccines against Bluetongue Virus serotype 8 were selected for the compulsory vaccination program carried out in Germany in 2008. The efficacy of these vaccines was evaluated in a pilot study in sheep immunised under field conditions by clinical, virological and serological examination before and after experimental challenge infection with a BTV-8 field isolate. Antibody levels prior to challenge infection differed between the vaccinated groups, but all seroconverted animals were fully protected against clinical disease and Virus replication. Only one vaccinated animal was very weakly positive in the real-time RT-PCR at day 10 after challenge infection, and one seronegative sheep in one of the vaccine groups was not protected.
Simon Carpenter - One of the best experts on this subject based on the ideXlab platform.
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investigating incursions of Bluetongue Virus using a model of long distance culicoides biting midge dispersal
Transboundary and Emerging Diseases, 2013Co-Authors: P S Mellor, Laura Burgin, J Gloster, Christopher Sanders, Simon Gubbins, Simon CarpenterAbstract:Bluetongue Virus (BTV) is an economically important pathogen of ruminants that is the aetiological agent of the haemorrhagic disease Bluetongue. Bluetongue Virus is biologically transmitted by Culicoides biting midges (Diptera: Ceratopogonidae), and long-range dispersal of infected vector species contributes substantially to the rapid spread of the Virus. The range of semi-passive flights of infected Culicoides on prevailing winds has been inferred to reach several hundred kilometres in a single night over water bodies. In this study, an atmospheric dispersion model was parameterized to simulate Culicoides flight activity based on dedicated entomological data sets collected in the UK. Five outbreaks of BTV in Europe were used to evaluate the model for use as an early warning tool and for retrospective analyses of BTV incursions. In each case, the generated predictions were consistent with epidemiological observations confirming its reliability for use in disease outbreak management. Furthermore, the model aided policy makers to predict, contain and eradicate BTV outbreaks in the UK during 2007 and 2008.
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culicoides and the emergence of Bluetongue Virus in northern europe
Trends in Microbiology, 2009Co-Authors: Simon Carpenter, Anthony J Wilson, P S MellorAbstract:In June 2006, Bluetongue Virus, an arboviral pathogen of ruminants, appeared in northern Europe for the first time, successfully overwintered and subsequently caused substantial losses to the farming sector in 2007 and 2008. This emergence served as a test of how the probability of arboviral incursion into new regions is assessed and has highlighted the reliance of decision making on paradigms that are not always underpinned by basic biological data. In this review, we highlight those areas of the epidemiology of Bluetongue that are poorly understood, reflect upon why certain vital areas of research have received little attention and, finally, examine strategies that could aid future risk assessment and intervention.
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experimental infection studies of uk culicoides species midges with Bluetongue Virus serotypes 8 and 9
Veterinary Record, 2008Co-Authors: Simon Carpenter, C Mcarthur, R Selby, R D Ward, D V Nolan, A Mordue J Luntz, J F Dallas, Frederic Tripet, P S MellorAbstract:This paper describes a rapid, standardised method for testing the susceptibility to Bluetongue Virus (btv) of northern Palaearctic Culicoides species midges that can be used to assess the competence of both field-caught and laboratory-infected midges. The method has been used to show that Culicoides scoticus can replicate btv serotype 8 and btv serotype 9 strains to more than 3 log 10 tcid50/midge, the first evidence of the potential of this species to transmit btv.
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quantifying Bluetongue Virus in adult culicoides biting midges diptera ceratopogonidae
Journal of Medical Entomology, 2008Co-Authors: Eva Veronesi, Andrew E Shaw, Peter P C Mertens, P S Mellor, Joe Brownlie, Simon CarpenterAbstract:A TissueLyser system (QIAGEN) was used to rapidly and accurately estimate Bluetongue Virus "loads" in individual adult Culicoides sonorensis Wirth & Jones (Diptera: Ceratopogonidae). The optimized homogenization program that was developed, involved shaking insects for 1 min at 25 Hz with 2- or 3-mm stainless steel ball bearings. This program was used to measure the quantities of Bluetongue Virus present in insects that had either been inoculated or had ingested a viremic bloodmeal through an artificial membrane. The Virus titers obtained using either infection technique and the optimized program did not differ significantly from those obtained using a polypropylene motor-driven pestle, a method that is currently in common use for studies of vector competence). The advantages of the new method, as a rapid means of detecting fully disseminated infections in individual field-caught flies, are discussed. Its use is compared with the processing of pools of Culicoides by conventional methods, where the extent of dissemination of the Virus is unknown and could wrongly implicate species that are of low importance in transmission.
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oral susceptibility to Bluetongue Virus of culicoides diptera ceratopogonidae from the united kingdom
Journal of Medical Entomology, 2006Co-Authors: Simon Carpenter, Heather L Lunt, Derah Arav, P S MellorAbstract:Oral susceptibility to infection with Bluetongue Virus (family Resviridae, genus OrbiVirus, BTV) serotype 9 was characterized in three Palaearctic species of Culicoides (Diptera: Ceratopogonidae). Variation in susceptibility to infection by using a recently described feeding technique was shown to occur between populations of Culicoides obsoletus Meigen complex midges from different geographic regions of the United Kingdom with Virus infection rates varying from 0.4 to 7.4% of those tested. Susceptibility to infection was consistent on an annual basis at selected sites. Prevalence of infection in the most susceptible populations of both the C. obsoletus and Culicoides pulicaris L. complexes was comparable with that of Culicoides imicola Kieffer, the major vector of BTV in southern Europe and throughout Africa, when using the same feeding method and Virus. These results are discussed with reference to the potential threat of the Virus to susceptible livestock in northern Europe.