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The American Journal of Tropical... Oct 2010Climate and environmental data were used to estimate the risk of testing positive for antibodies to bluetongue (BTV) and epizootic hemorrhagic disease viruses (EHDV) in...
Climate and environmental data were used to estimate the risk of testing positive for antibodies to bluetongue (BTV) and epizootic hemorrhagic disease viruses (EHDV) in cattle in Illinois and western Indiana over three transmission seasons (2000-2002). The risks of BTV and EHDV seropositivity were positively associated with temperature during every year of the study. The EHDV seropositivity was also positively associated with forest patchiness in two of the years. During 2002, a year with unusually high spring rainfall, forest patchiness was not significantly associated with EHDV but spring rainfall did have a moderating effect on temperature. Maps of predicted probability of exposure to BTV or EHDV were created using these best-fitting models and show distinctly different spatial patterns within the same cattle population.
Topics: Animals; Bluetongue virus; Cattle; Cattle Diseases; Climate; Ecosystem; Geography; Hemorrhagic Disease Virus, Epizootic; Illinois; Indiana; Reoviridae Infections; Risk Factors; Time Factors
PubMed: 20889866
DOI: 10.4269/ajtmh.2010.10-0132 -
Virology Journal Apr 2008The genus Orbivirus includes several species that infect livestock - including Bluetongue virus (BTV) and African horse sickness virus (AHSV). These viruses have linear...
BACKGROUND
The genus Orbivirus includes several species that infect livestock - including Bluetongue virus (BTV) and African horse sickness virus (AHSV). These viruses have linear dsRNA genomes divided into ten segments, all of which have previously been assumed to be monocistronic.
RESULTS
Bioinformatic evidence is presented for a short overlapping coding sequence (CDS) in the Orbivirus genome segment 9, overlapping the VP6 cistron in the +1 reading frame. In BTV, a 77-79 codon AUG-initiated open reading frame (hereafter ORFX) is present in all 48 segment 9 sequences analysed. The pattern of base variations across the 48-sequence alignment indicates that ORFX is subject to functional constraints at the amino acid level (even when the constraints due to coding in the overlapping VP6 reading frame are taken into account; MLOGD software). In fact the translated ORFX shows greater amino acid conservation than the overlapping region of VP6. The ORFX AUG codon has a strong Kozak context in all 48 sequences. Each has only one or two upstream AUG codons, always in the VP6 reading frame, and (with a single exception) always with weak or medium Kozak context. Thus, in BTV, ORFX may be translated via leaky scanning. A long (83-169 codon) ORF is present in a corresponding location and reading frame in all other Orbivirus species analysed except Saint Croix River virus (SCRV; the most divergent). Again, the pattern of base variations across sequence alignments indicates multiple coding in the VP6 and ORFX reading frames.
CONCLUSION
At approximately 9.5 kDa, the putative ORFX product in BTV is too small to appear on most published protein gels. Nonetheless, a review of past literature reveals a number of possible detections. We hope that presentation of this bioinformatic analysis will stimulate an attempt to experimentally verify the expression and functional role of ORFX, and hence lead to a greater understanding of the molecular biology of these important pathogens.
Topics: Bluetongue virus; Capsid Proteins; Computational Biology; Genes, Overlapping; Genes, Viral; Open Reading Frames; Orbivirus; Phylogeny; Viral Proteins
PubMed: 18489030
DOI: 10.1186/1743-422X-5-48 -
Research in Veterinary Science Dec 2011The Toggenburg orbivirus (TOV), a recently discovered virus related to bluetongue virus (BTV), has been identified in goats in Switzerland, Italy and Germany. Isolation...
The Toggenburg orbivirus (TOV), a recently discovered virus related to bluetongue virus (BTV), has been identified in goats in Switzerland, Italy and Germany. Isolation of TOV in vitro has not yet been achieved and the transmission mechanisms are still unknown. In the experimental infection of pregnant goats described here, TOV could not be detected in secretion/excretion samples or fetal blood. Material from the goat experiment was used as inoculum for propagating the virus in vitro. To enhance the infectivity of TOV several modified protocols, e.g. pretreatment of the virus with trypsin, polyethylene glycol-mediated infection and lipofection were applied. Isolation of TOV, attempts to infect Culicoides nubeculosus by feeding TOV-positive blood and intracerebral inoculation of newborn mice were unsuccessful. The results of these studies suggest that TOV requires specific but different factors than other BTVs for infection and replication outside of its natural caprine host.
Topics: Animals; Animals, Newborn; Cell Line; Ceratopogonidae; Female; Goat Diseases; Goats; Insect Vectors; Mice; Orbivirus; Pregnancy; Virus Replication; Virus Shedding
PubMed: 21458013
DOI: 10.1016/j.rvsc.2011.03.007 -
Trends in Microbiology Nov 1993Virus assembly within infected cells involves a precise sequence of macromolecular interactions. To unravel the individual steps involved in the assembly of a complete... (Review)
Review
Virus assembly within infected cells involves a precise sequence of macromolecular interactions. To unravel the individual steps involved in the assembly of a complete virion of bluetongue virus, we have engineered a series of recombinant baculoviruses to make multicomponent structures resembling virus structures. When combined with cryoelectron microscopy and image processing techniques the data reveal the organization and assembly of the various components of this virus.
Topics: Baculoviridae; Capsid; Orbivirus; Viral Structural Proteins; Virion
PubMed: 8162414
DOI: 10.1016/0966-842x(93)90006-d -
Veterinaria Italiana 2015Although bluetongue viruses (BTV) and epizootic haemorrhagic disease viruses (EHDV) are closely related, there are differences in susceptibility to these viruses both...
Although bluetongue viruses (BTV) and epizootic haemorrhagic disease viruses (EHDV) are closely related, there are differences in susceptibility to these viruses both between and within a species. White‑tailed deer are susceptible to disease by both BTV and EHDV, sheep are susceptible to BTV, but resistant to EHDV, and cattle can be infected with both viruses but disease is usually subclinical. Host genetics probably play a role in the disease outcome, but cytokine and endothelial responses are likely to determine if subclinical or clinical disease develops. Dendritic macrophages deliver virus to lymph nodes following the bite of an infected Culicoides. The virus then disseminates to many organs replicating in mononuclear phagocytes and endothelium. Initially, an interferon‑1 response probably determines if the disease develops. Replication in mononuclear cells and endothelium results in the release of cytokines and vasoactive mediators, and may result in endothelial cell death leading to the clinical features of fever, hyperaemia, exudation of fluid, and haemorrhage. Disease outcome may also be linked to virus binding Toll‑like receptor‑3 and upregulation of endothelial surface receptors potentiating cytokine release and allowing transmigration of inflammatory cells, respectively. Despite a wealth of information, host genetics involved in resistance to BTV and EHDV and how variations in cytokines and endothelial responses determine clinical outcome still need further elucidation.
Topics: Animals; Bluetongue; Cattle; Cytokines; Hemorrhagic Disease Virus, Epizootic; Orbivirus; Reoviridae Infections; Sheep
PubMed: 26741244
DOI: 10.12834/VetIt.593.2854.1 -
Archives of Virology Oct 2014An orbivirus was isolated from a sample from the ornithophilic mosquito Culex sasai in Japan. The virus, designated Koyama Hill virus (KHV), replicated to high titer in...
An orbivirus was isolated from a sample from the ornithophilic mosquito Culex sasai in Japan. The virus, designated Koyama Hill virus (KHV), replicated to high titer in a mosquito cell line and to a low titer in an avian cell line, but the release of progeny viruses was not observed in mammalian cell lines inoculated with KHV. Electron microscopic examination of KHV-infected mosquito cells showed approximately 70-nm virus particles and viral tubules typical of members of the genus Orbivirus, family Reoviridae. KHV efficiently replicated in Cx. sasai mosquitoes, suggesting a potential vector species for KHV transmission in nature. Full-length viral genome sequencing and phylogenetic analysis revealed that KHV is closely related to Umatilla virus (UMAV) and Stretch Lagoon orbivirus (SLOV). This suggests that KHV is a new member of the species Umatilla virus, an orbivirus species not previously observed in East Asia. The KHV genome segment encoding NS1 contains a notable sequence deletion and heterogeneity compared with a prototype UMAV, which may affect its growth properties and pathogenicity in host cells. These results provide new insights into the genetic diversity and geographic distribution of members of the species Umatilla virus.
Topics: Amino Acid Sequence; Animals; Base Sequence; Cell Line; Culex; Microscopy, Electron; Molecular Sequence Data; Orbivirus; Phylogeny; RNA, Viral; Reoviridae Infections; Sequence Analysis, DNA; Viral Nonstructural Proteins; Virus Replication
PubMed: 24906523
DOI: 10.1007/s00705-014-2117-0 -
Virus Research Mar 2014The members of Orbivirus genus within the Reoviridae family are arthropod-borne viruses which are responsible for high morbidity and mortality in ruminants. Bluetongue... (Review)
Review
The members of Orbivirus genus within the Reoviridae family are arthropod-borne viruses which are responsible for high morbidity and mortality in ruminants. Bluetongue virus (BTV) which causes disease in livestock (sheep, goat, cattle) has been in the forefront of molecular studies for the last three decades and now represents the best understood orbivirus at a molecular and structural level. The complex nature of the virion structure has been well characterised at high resolution along with the definition of the virus encoded enzymes required for RNA replication; the ordered assembly of the capsid shell as well as the protein and genome sequestration required for it; and the role of host proteins in virus entry and virus release. More recent developments of Reverse Genetics and Cell-Free Assembly systems have allowed integration of the accumulated structural and molecular knowledge to be tested at meticulous level, yielding higher insight into basic molecular virology, from which the rational design of safe efficacious vaccines has been possible. This article is centred on the molecular dissection of BTV with a view to understanding the role of each protein in the virus replication cycle. These areas are important in themselves for BTV replication but they also indicate the pathways that related viruses, which includes viruses that are pathogenic to man and animals, might also use providing an informed starting point for intervention or prevention.
Topics: Animals; Bluetongue virus; Molecular Biology; Viral Proteins; Virus Replication
PubMed: 24370866
DOI: 10.1016/j.virusres.2013.12.017 -
Comparative Immunology, Microbiology... 1994African horse sickness virus (AHSV), of which there are nine serotypes (AHSV-1, -2, etc.), is a member of Orbivirus genus within the Reoviridae family. Both in... (Review)
Review
African horse sickness virus (AHSV), of which there are nine serotypes (AHSV-1, -2, etc.), is a member of Orbivirus genus within the Reoviridae family. Both in morphology and molecular constituents AHSV particles are comparable to those of bluetongue virus (BTV), the prototype virus of the genus. The two viruses have seven structural proteins (VP1-7) organized in two layered capsid. The outer capsid is composed of VP2 and VP5. The inner capsid, or core, is composed of two major proteins, VP3 and VP7, and three minor proteins, VP1, VP4 and VP6. Within the core is the virus genome. This genome consists of 10 double-stranded (ds)RNA segments of different sizes, three large, designated L1-L3, three medium, M4-M6, and four small, S7-S10. In addition to the seven structural proteins that are coded by seven of the RNA species, four non-structural proteins, NS1, NS2, NS3 and NS3A, are coded by three RNA segments, M5, S8 and S10. The two smallest proteins (NS3 and NS3A) are synthesized by the S10 RNA segment, probably from different in-frame translation initiation codons. Nucleotide sequences of eight RNA segments (L2, L3, M4, M5, M6, S7, S8 and S10) and the predicted amino acid sequences of the encoded gene products are also available, mainly representing one serotype, AHSV-4. In this review the properties of the AHSV genes and gene products are discussed. The sequence and hybridization analyses of the different AHSV dsRNA segments indicate that the segments that code for the core proteins, as well as those that code for NS1 and NS2 proteins, are highly conserved between the different virus serotypes. However, the RNA encoding NS3 and NS3A, and the two segments encoding the outer capsid proteins, are more variable between the AHSV serotypes. A close phylogenetic relationship between AHSV, BTV and epizootic haemorrhagic disease virus (EHDV), three Culicoides-transmitted orbiviruses, has been revealed when the equivalent sequences of genes and gene products are compared. Recently, the four major AHSV capsid proteins have been expressed using recombinant baculoviruses. Biochemically and antigenically these proteins are similar to the authentic proteins. Since the AHSV VP7 protein is highly conserved among the different serotypes, it has been utilized as a diagnostic reagent. The expressed VP7 protein has also been purified to homogeneity and crystallized for three-dimensional X-ray analysis.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: African Horse Sickness Virus; Amino Acid Sequence; Animals; Base Sequence; Molecular Sequence Data; RNA, Viral; Viral Proteins
PubMed: 8001348
DOI: 10.1016/0147-9571(94)90046-9 -
The Journal of General Virology Jun 2009Stretch Lagoon orbivirus (SLOV) was isolated in 2002 from pooled Culex annulirostris mosquitoes collected at Stretch Lagoon, near the Wolfe Creek national park in the...
Stretch Lagoon orbivirus (SLOV) was isolated in 2002 from pooled Culex annulirostris mosquitoes collected at Stretch Lagoon, near the Wolfe Creek national park in the Kimberley region of Western Australia. Conventional serological tests were unable to identify the isolate, and electron microscopy indicated a virus of the genus Orbivirus, family Reoviridae. Here, a cDNA subtraction method was used to obtain approximately one-third of the viral genome, and further sequencing was performed to complete the sequences of segment 1 (viral polymerase) and segment 2 (conserved inner-core protein). Phylogenetic analysis showed that SLOV should be considered a new species within the genus Orbivirus. A real-time RT-PCR test was designed to study the epidemiology of SLOV in the field. Six additional isolates of SLOV were identified, including isolates from four additional locations and two additional mosquito species. Horses, donkeys and goats were implicated as potential vertebrate hosts in a serological survey.
Topics: Aedes; Animals; Australia; Base Sequence; Cell Line; Cluster Analysis; Cricetinae; Culex; DNA, Complementary; Molecular Sequence Data; Orbivirus; Phylogeny; RNA, Viral; Reoviridae Infections; Sequence Analysis, DNA; Sequence Homology
PubMed: 19282430
DOI: 10.1099/vir.0.010074-0 -
Archives of Virology 1984
Review
Topics: Antigens, Viral; Bluetongue virus; Genes, Viral; Molecular Weight; RNA, Double-Stranded; RNA, Viral; Reoviridae; Viral Proteins; Virus Replication
PubMed: 6093741
DOI: 10.1007/BF01309364