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Revue Scientifique Et Technique... Aug 2015African horse sickness (AHS) is a devastating disease of equids caused by an arthropod-borne virus belonging to the Reoviridae family, genus Orbivirus. It is considered... (Review)
Review
African horse sickness (AHS) is a devastating disease of equids caused by an arthropod-borne virus belonging to the Reoviridae family, genus Orbivirus. It is considered a major health threat for horses in endemic areas in sub-Saharan Africa. African horse sickness virus (AHSV) repeatedly caused large epizootics in the Mediterranean region (North Africa and southern Europe in particular) as a result of trade in infected equids. The unexpected emergence of a closely related virus, the bluetongue virus, in northern Europe in 2006 has raised fears about AHSV introduction into Europe, and more specifically into AHSV-free regions that have reported the presence of AHSV vectors, e.g. Culicoides midges. North African and European countries should be prepared to face AHSV incursions in the future, especially since two AHSV serotypes (serotypes 2 and 7) have recently spread northwards to western (e.g. Senegal, Nigeria, Gambia) and eastern Africa (Ethiopia), where historically only serotype 9 had been isolated. The authors review key elements of AHS epidemiology, surveillance and prophylaxis.
Topics: Africa; African Horse Sickness; Animals; Horses; Orbivirus
PubMed: 26601437
DOI: 10.20506/rst.34.2.2359 -
Revue Scientifique Et Technique... Aug 2015Summary Epizootic haemorrhagic disease (EHD) is an arthropod-transmitted viral disease of certain wild ungulates, notably North American white-tailed deer and, more... (Review)
Review
Summary Epizootic haemorrhagic disease (EHD) is an arthropod-transmitted viral disease of certain wild ungulates, notably North American white-tailed deer and, more rarely, cattle. The disease in white-tailed deer results from vascular injury analogous to that caused by bluetongue virus (BTV), to which EHD virus (EHDV) is closely related. There are seven serotypes of EHDV recognised, and Ibaraki virus, which is the cause of sporadic disease outbreaks in cattle in Asia, is included in EHDV serotype 2. The global distribution and epidemiology of BTV and EHDV infections are also similar, as both viruses occur throughout temperate and tropical regions of the world where they are transmitted by biting Culicoides midges and infect a wide variety of domestic and wild ungulates. However, the global distribution and epidemiology of EHDV infection are less well characterised than they are for BTV. Whereas most natural and experimental EHDV infections (other than Ibaraki virus infection) of livestock are subclinical or asymptomatic, outbreaks of EHD have recently been reported among cattle in the Mediterranean Basin, Reunion Island, South Africa, and the United States. Accurate and convenient laboratory tests are increasingly available for the sensitive and specific serological and virological diagnosis of EHDV infection and confirmation of EHD in animals, but commercial vaccines are available only for prevention of Ibaraki disease and not for protection against other strains and serotypes of EHDV.
Topics: Animals; Cattle; Disease Outbreaks; Hemorrhagic Disease Virus, Epizootic; Reoviridae Infections
PubMed: 26601439
DOI: 10.20506/rst.34.2.2361 -
Viruses Mar 2019While serological and virological evidence documents the exposure of bats to medically-important arboviruses, their role as reservoirs or amplifying hosts is less...
While serological and virological evidence documents the exposure of bats to medically-important arboviruses, their role as reservoirs or amplifying hosts is less well-characterized. We describe a novel orbivirus () isolated from an Egyptian fruit bat () trapped in 2013 in Uganda and named Bukakata orbivirus. This is the fifth orbivirus isolated from a bat, however genetic information had previously only been available for one bat-associated orbivirus. We performed whole-genome sequencing on Bukakata orbivirus and three other bat-associated orbiviruses (Fomede, Ife, and Japanaut) to assess their phylogenetic relationship within the genus and develop hypotheses regarding potential arthropod vectors. Replication kinetics were assessed for Bukakata orbivirus in three different vertebrate cell lines. Lastly, qRT-PCR and nested PCR were used to determine the prevalence of Bukakata orbivirus RNA in archived samples from three populations of Egyptian fruit bats and one population of cave-associated soft ticks in Uganda. Complete coding sequences were obtained for all ten segments of Fomede, Ife, and Japanaut orbiviruses and for nine of the ten segments for Bukakata orbivirus. Phylogenetic analysis placed Bukakata and Fomede in the tick-borne orbivirus clade and Ife and Japanaut within the /phlebotomine sandfly orbivirus clade. Further, Bukakata and Fomede appear to be serotypes of the species. Bukakata orbivirus replicated to high titers (10⁶⁻10⁷ PFU/mL) in Vero, BHK-21 [C-13], and R06E (Egyptian fruit bat) cells. Preliminary screening of archived bat and tick samples do not support Bukakata orbivirus presence in these collections, however additional testing is warranted given the phylogenetic associations observed. This study provided complete coding sequence for several bat-associated orbiviruses and in vitro characterization of a bat-associated orbivirus. Our results indicate that bats may play an important role in the epidemiology of viruses in the genus and further investigation is warranted into vector-host associations and ongoing surveillance efforts.
Topics: Animals; Cell Line; Chiroptera; Chlorocebus aethiops; Disease Reservoirs; Genome, Viral; Open Reading Frames; Orbivirus; Phylogeny; RNA, Viral; Real-Time Polymerase Chain Reaction; Sequence Analysis, DNA; Vero Cells; Viral Proteins; Virus Replication; Whole Genome Sequencing
PubMed: 30832334
DOI: 10.3390/v11030209 -
Advances in Virus Research 2020Bluetongue 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... (Review)
Review
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 10 double-stranded (ds) RNA segments. BTV has been studied extensively as a model system for large, nonenveloped dsRNA viruses. A combination of recombinant proteins and particles together with reverse genetics, high-resolution structural analysis by X-ray crystallography and cryo-electron microscopy techniques have been utilized to provide an order for the assembly of the capsid shell and the protein sequestration required for it. Further, a reconstituted in vitro assembly system and RNA-RNA interaction assay, have defined the individual steps required for the assembly and packaging of the 10-segmented RNA genome. In addition, various microscopic techniques have been utilized to illuminate the stages of virus maturation and its egress via multiple pathways. These findings have not only given an overall understanding of BTV assembly and morphogenesis but also indicated that similar assembly and egress pathways are likely to be used by related viruses and provided an informed starting point for intervention or prevention.
Topics: Animals; Bluetongue virus; Books; Capsid; Capsid Proteins; Cryoelectron Microscopy; Genome, Viral; Insect Vectors; Livestock; Viral Proteins; Virion; Virus Assembly; Virus Release; Virus Replication
PubMed: 33837718
DOI: 10.1016/bs.aivir.2020.08.002 -
Virus Research Aug 2020A novel orbivirus had been identified as a member of the Orbivirus genus, which was isolated from pooled Culex fatigans mosquitoes in Guangdong of China, named as the...
A novel orbivirus had been identified as a member of the Orbivirus genus, which was isolated from pooled Culex fatigans mosquitoes in Guangdong of China, named as the Fengkai virus (FKOV). The cytopathic effects (CPEs) on both Aedes albopictus cells (C6/36) and mammalian cell lines (Vero and BHK-21) emerged in the cell cultures inoculated above virus in. Experimental confirmation as the Orbivirus genus was conducted by the Real-time PCR and based on Ion Torrent Next-Generation in sequencing. The Identities of VP1, VP2 and VP3 in amino acid sequences between the Tibet orbivirus (TIBOV) and this strain were 98.6%, 42.9%, and 99.9%, respectively, which indicated that this strain shares the same genus (VP1, Pol) and species (VP3, T2) with TIBOV but was greatly different in VP2 and VP5 (10.3%) of TIBOV. The VP2 and VP5 diversities of both TIBOV and FKOV strains suggested both serotypes are distinct with each other. As natural evolution and circulation, this strain might expand its host ranges and infect human beings as a potential and severe pathogen.
Topics: Aedes; Animals; China; Chlorocebus aethiops; Culex; Cytopathogenic Effect, Viral; Genome, Viral; Host Specificity; Orbivirus; Phylogeny; Vero Cells; Viral Proteins
PubMed: 32437817
DOI: 10.1016/j.virusres.2020.197990 -
Frontiers in Cellular and Infection... 2024Tibet orbivirus (TIBOV) was first isolated from mosquitoes in Xizang, China, in 2009. In recent years, more TIBOV strains have been isolated in several provinces across...
Tibet orbivirus (TIBOV) was first isolated from mosquitoes in Xizang, China, in 2009. In recent years, more TIBOV strains have been isolated in several provinces across China, Japan, East Asia, and Nepal, South Asia. Furthermore, TIBOVs have also been isolated from mosquitoes, and several midge species. Additionally, TIBOV neutralizing antibodies have been detected in serum specimens from several mammals, including cattle, sheep, and pigs. All of the evidence suggests that the geographical distribution of TIBOVs has significantly expanded in recent years, with an increased number of vector species involved in its transmission. Moreover, the virus demonstrated infectivity towards a variety of animals. Although TIBOV is considered an emerging orbivirus, detailed reports on its genome and molecular evolution are currently lacking. Thus, this study performed the whole-genome nucleotide sequencing of three TIBOV isolates from mosquitoes and midges collected in China in 2009, 2011, and 2019. Furthermore, the genome and molecular genetic evolution of TIBOVs isolated from different countries, periods, and hosts (mosquitoes, midges, and cattle) was systematically analyzed. The results revealed no molecular specificity among TIBOVs isolated from different countries, periods, and vectors. Meanwhile, the time-scaled phylogenetic analysis demonstrated that the most recent common ancestor (TMRCA) of TIBOV appeared approximately 797 years ago (95% HPD: 16-2347) and subsequently differentiated at least three times, resulting in three distinct genotypes. The evolutionary rate of TIBOVs was about 2.12 × 10 nucleotide substitutions per site per year (s/s/y) (95% HPD: 3.07 × 10, 9.63 × 10), which is similar to that of the bluetongue virus (BTV), also in the genus. Structural analyses of the viral proteins revealed that the three-dimensional structures of the outer capsid proteins of TIBOV and BTV were similar. These results suggest that TIBOV is a newly discovered and rapidly evolving virus transmitted by various blood-sucking insects. Given the potential public health burden of this virus and its high infectious rate in a wide range of animals, it is significant to strengthen research on the genetic variation of TIBOVs in blood-feeding insects and mammals in the natural environment and the infection status in animals.
Topics: Cattle; Animals; Sheep; Swine; Orbivirus; Tibet; Phylogeny; Mosquito Vectors; Anopheles; Mammals; Nucleotides; Genome, Viral; Reoviridae Infections
PubMed: 38505291
DOI: 10.3389/fcimb.2024.1327780 -
Virology Feb 1996Orbiviruses (Reoviridae family) are complex nonenveloped RNA viruses with seven structural proteins and a RNA genome consisting of 10 variously sized double-stranded RNA... (Review)
Review
Orbiviruses (Reoviridae family) are complex nonenveloped RNA viruses with seven structural proteins and a RNA genome consisting of 10 variously sized double-stranded RNA segments. Significant advances in orbivirus research have been made in recent years through the use of gene manipulation techniques coupled with the baculovirus expression system. Several orbivirus proteins have yielded to crystallization and X-ray crystallographic structure determination and, when combined with the three-dimensional image reconstruction of virion particles and cores obtained by cryoelectron microscopy, considerable insight has been gained into the intricate organization and topography of the individual viral components. Formal identification of the sites of interaction has been obtained through protein-protein interaction studies on the components of the virion particle, including those that are involved in capsid assembly. Finally, a beginning of the understanding of the sequence of assembly events has also been obtained.
Topics: Animals; Bluetongue virus; Orbivirus; Viral Proteins; Virus Assembly
PubMed: 8614976
DOI: 10.1006/viro.1996.0028 -
Revue Scientifique Et Technique... Aug 2015Many novel emerging orbiviruses have been isolated in the past 15 years. Important viruses include Peruvian horse sickness virus (PHSV) and Yunnan orbivirus (YUOV),...
Many novel emerging orbiviruses have been isolated in the past 15 years. Important viruses include Peruvian horse sickness virus (PHSV) and Yunnan orbivirus (YUOV), pathogens of equids which were originally isolated almost simultaneously from 1997 to 1999 in the People's Republic of China, Australia and Peru. YUOV has also been isolated from cattle, sheep and a dog. The isolation of YUOVfrom a dog is not the first case of an orbivirus being isolated from a carnivore. Bluetongue virus and African horse sickness virus were earlier detected in carnivores which fed on contaminated meat. PHSV and YUOV both offer an opportunity to study the emergence of a single pathogen in geographically distant locations, although the original point of emergence is still unidentified. PHSV has been isolated from horses with neurological disease both in Australia and in Peru (where it is now endemic). Serological and molecular diagnostic assays have been developed for these viruses to assist in their identification and diagnosis. Other orbiviruses, such as Palyam virus and Equine encephalosis virus, have more recently been identified outside their geographical boundaries and may represent a threat to domesticated livestock and horses, respectively. The article also reviews four zoonotic orbivirus species (Corriparta virus, Changuinola virus, Kemerovo virus and Orungo virus) which have been identified in livestock and/or wildlife.
Topics: Animals; Communicable Diseases, Emerging; Humans; Orbivirus; Reoviridae Infections; Zoonoses
PubMed: 26601440
DOI: 10.20506/rst.34.2.2362 -
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 -
Methods (San Diego, Calif.) Aug 2017Fluorescent tags constitute an invaluable tool in facilitating a deeper understanding of the mechanistic processes governing virus-host interactions. However, when... (Review)
Review
Fluorescent tags constitute an invaluable tool in facilitating a deeper understanding of the mechanistic processes governing virus-host interactions. However, when selecting a fluorescent tag for in vivo imaging of cells, a number of parameters and aspects must be considered. These include whether the tag may affect and interfere with protein conformation or localization, cell toxicity, spectral overlap, photo-stability and background. Cumulatively, these constitute challenges to be overcome. Bluetongue virus (BTV), a member of the Orbivirus genus in the Reoviridae family, is a non-enveloped virus that is comprised of two architecturally complex capsids. The outer capsid, composed of two proteins, VP2 and VP5, together facilitate BTV attachment, entry and the delivery of the transcriptionally active core in the cell cytoplasm. Previously, the significance of the endocytic pathway for BTV entry was reported, although a detailed analysis of the role of each protein during virus trafficking remained elusive due to the unavailability of a tagged virus. Described here is the successful modification, and validation, of a segmented genome belonging to a complex and large capsid virus to introduce tags for fluorescence visualization. The data generated from this approach highlighted the sequential dissociation of VP2 and VP5, driven by decreasing pH during the transition from early to late endosomes, and their retention therein as the virus particles progress along the endocytic pathway. Furthermore, the described tagging technology and methodology may prove transferable and allow for the labeling of other non-enveloped complex viruses.
Topics: Animals; Bluetongue virus; Host-Pathogen Interactions; Microbiological Techniques; Virology; Virus Internalization
PubMed: 28802715
DOI: 10.1016/j.ymeth.2017.08.004