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Journal of Invertebrate Pathology Jun 2024Insects have a rich diversity of RNA viruses that can either cause acute infections or persist in host populations without visible symptoms. The melon fly, Zeugodacus...
Insects have a rich diversity of RNA viruses that can either cause acute infections or persist in host populations without visible symptoms. The melon fly, Zeugodacus cucurbitae (Tephritidae) causes substantial economic losses through infestation of diverse cucurbit and other crops. Of Indomalayan origin, it is now established in many tropical regions of the world. The virome diversity of Z. cucurbitae is largely unknown across large parts of its distribution, including the Indian subcontinent. We have analysed three transcriptomes each of one field-collected and one laboratory-reared Z. cucurbitae population from Bangalore (India) and discovered genomes of ten putative RNA viruses: two sigmaviruses, one chimbavirus, one cripavirus, one noda-like virus, one nora virus, one orbivirus, one partiti-like virus, one sobemovirus and one toti-like virus. Analysis of the only available host genome of a Hawaiian Z. cucurbitae population did not detect host genome integration of the detected viruses. While all ten viruses were found in the Bangalore field population only seven were detected in the laboratory population, indicating that these seven may cause persistent covert infections. Using virus-specific RNA-dependent RNA polymerase gene primers, we detected nine of the RNA viruses with an overall low variant diversity in some but not all individual flies from four out of five Indian regions. We then screened 39 transcriptomes of Z. cucurbitae laboratory populations from eastern Asia (Guangdong, Hainan, Taiwan) and the Pacific region (Hawaii), and detected seven of the ten virus genomes. We found additional genomes of a picorna-like virus and a negev-like virus. Hawaii as the only tested population from the fly's invasive range only had one virus. Our study provides evidence of new and high RNA virus diversity in Indian populations within the original range of Z. cucurbitae, as well as the presence of persistent covert infections in laboratory populations. It builds the basis for future research of tephritid-associated RNA viruses, including their host effects, epidemiology and application potential in biological control.
Topics: Animals; RNA Viruses; Tephritidae; India; Genome, Viral; Transcriptome; Virome
PubMed: 38679365
DOI: 10.1016/j.jip.2024.108117 -
Viruses Apr 2024A devastating bluetongue (BT) epidemic caused by bluetongue virus serotype 3 (BTV-3) has spread throughout most of the Netherlands within two months since the first...
A devastating bluetongue (BT) epidemic caused by bluetongue virus serotype 3 (BTV-3) has spread throughout most of the Netherlands within two months since the first infection was officially confirmed in the beginning of September 2023. The epidemic comes with unusually strong suffering of infected cattle through severe lameness, often resulting in mortality or euthanisation for welfare reasons. In total, tens of thousands of sheep have died or had to be euthanised. By October 2023, more than 2200 locations with ruminant livestock were officially identified to be infected with BTV-3, and additionally, ruminants from 1300 locations were showing BTV-associated clinical symptoms (but not laboratory-confirmed BT). Here, we report on the spatial spread and dynamics of this BT epidemic. More specifically, we characterized the distance-dependent intensity of the between-holding transmission by estimating the spatial transmission kernel and by comparing it to transmission kernels estimated earlier for BTV-8 transmission in Northwestern Europe in 2006 and 2007. The 2023 BTV-3 kernel parameters are in line with those of the transmission kernel estimated previously for the between-holding spread of BTV-8 in Europe in 2007. The 2023 BTV-3 transmission kernel has a long-distance spatial range (across tens of kilometres), evidencing that in addition to short-distance dispersal of infected midges, other transmission routes such as livestock transports probably played an important role.
Topics: Animals; Bluetongue; Bluetongue virus; Netherlands; Sheep; Serogroup; Cattle; Epidemics; Cattle Diseases
PubMed: 38675966
DOI: 10.3390/v16040625 -
Viruses Mar 2024Many protein expression systems are primarily utilised to produce a single, specific recombinant protein. In contrast, most biological processes such as virus assembly... (Review)
Review
Many protein expression systems are primarily utilised to produce a single, specific recombinant protein. In contrast, most biological processes such as virus assembly rely upon a complex of several interacting proteins rather than the activity of a sole protein. The high complexity of the baculovirus genome, coupled with a multiphase replication cycle incorporating distinct transcriptional steps, made it the ideal system to manipulate for high-level expression of a single, or co-expression of multiple, foreign proteins within a single cell. We have developed and utilised a series of recombinant baculovirus systems to unravel the sequential assembly process of a complex non-enveloped model virus, bluetongue virus (BTV). The high protein yields expressed by the baculovirus system not only facilitated structure-function analysis of each viral protein but were also advantageous to crystallography studies and supported the first atomic-level resolution of a recombinant viral protein, the major BTV capsid protein. Further, the formation of recombinant double-shelled virus-like particles (VLPs) provided insights into the structure-function relationships among the four major structural proteins of the BTV whilst also representing a potential candidate for a viral vaccine. The baculovirus multi-gene expression system facilitated the study of structurally complex viruses (both non-enveloped and enveloped viruses) and heralded a new generation of viral vaccines.
Topics: Baculoviridae; Recombinant Proteins; Animals; Gene Expression; Bluetongue virus; Genetic Vectors; Virus Assembly; Viral Proteins; Capsid Proteins
PubMed: 38675835
DOI: 10.3390/v16040492 -
PloS One 2024A safe, highly immunogenic multivalent vaccine to protect against all nine serotypes of African horse sickness virus (AHSV), will revolutionise the AHS vaccine industry...
A safe, highly immunogenic multivalent vaccine to protect against all nine serotypes of African horse sickness virus (AHSV), will revolutionise the AHS vaccine industry in endemic countries and beyond. Plant-produced AHS virus-like particles (VLPs) and soluble viral protein 2 (VP2) vaccine candidates were developed that have the potential to protect against all nine serotypes but can equally well be formulated as mono- and bi-valent formulations for localised outbreaks of specific serotypes. In the first interferon α/β receptor knock-out (IFNAR-/-) mice trial conducted, a nine-serotype (nonavalent) vaccine administered as two pentavalent (5 μg per serotype) vaccines (VLP/VP2 combination or exclusively VP2), were directly compared to the commercially available AHS live attenuated vaccine. In a follow up trial, mice were vaccinated with an adjuvanted nine-serotype multivalent VP2 vaccine in a prime boost strategy and resulted in the desired neutralising antibody titres of 1:320, previously demonstrated to confer protective immunity in IFNAR-/- mice. In addition, the plant-produced VP2 vaccine performed favourably when compared to the commercial vaccine. Here we provide compelling data for a nonavalent VP2-based vaccine candidate, with the VP2 from each serotype being antigenically distinguishable based on LC-MS/MS and ELISA data. This is the first preclinical trial demonstrating the ability of an adjuvanted nonavalent cocktail of soluble, plant-expressed AHS VP2 proteins administered in a prime-boost strategy eliciting high antibody titres against all 9 AHSV serotypes. Furthermore, elevated T helper cells 2 (Th2) and Th1, indicative of humoral and cell-mediated memory T cell immune responses, respectively, were detected in mouse serum collected 14 days after the multivalent prime-boost vaccination. Both Th2 and Th1 may play a role to confer protective immunity. These preclinical immunogenicity studies paved the way to test the safety and protective efficacy of the plant-produced nonavalent VP2 vaccine candidate in the target animals, horses.
Topics: Animals; Mice; Horses; African Horse Sickness Virus; African Horse Sickness; Vaccines, Combined; Chromatography, Liquid; Capsid Proteins; Tandem Mass Spectrometry; Viral Vaccines; Antibodies, Viral
PubMed: 38625924
DOI: 10.1371/journal.pone.0301340 -
Cell Apr 2024Unlike those of double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), and ssRNA viruses, the mechanism of genome packaging of dsRNA viruses is poorly understood....
Unlike those of double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), and ssRNA viruses, the mechanism of genome packaging of dsRNA viruses is poorly understood. Here, we combined the techniques of high-resolution cryoelectron microscopy (cryo-EM), cellular cryoelectron tomography (cryo-ET), and structure-guided mutagenesis to investigate genome packaging and capsid assembly of bluetongue virus (BTV), a member of the Reoviridae family of dsRNA viruses. A total of eleven assembly states of BTV capsid were captured, with resolutions up to 2.8 Å, with most visualized in the host cytoplasm. ATPase VP6 was found underneath the vertices of capsid shell protein VP3 as an RNA-harboring pentamer, facilitating RNA packaging. RNA packaging expands the VP3 shell, which then engages middle- and outer-layer proteins to generate infectious virions. These revealed "duality" characteristics of the BTV assembly mechanism reconcile previous contradictory co-assembly and core-filling models and provide insights into the mysterious RNA packaging and capsid assembly of Reoviridae members and beyond.
Topics: Bluetongue virus; Capsid; Cryoelectron Microscopy; Capsid Proteins; Animals; Viral Genome Packaging; RNA, Viral; Genome, Viral; Virus Assembly; Electron Microscope Tomography; Virion; Models, Molecular; Cell Line; Cricetinae
PubMed: 38614100
DOI: 10.1016/j.cell.2024.03.007 -
Veterinary Microbiology May 2024Epizootic hemorrhagic disease (EHD) virus serotype 8 (EHDV-8) emerged in Spain in autumn 2022. In this study, we aimed to (1) characterize the clinical and lesional...
Epizootic hemorrhagic disease (EHD) virus serotype 8 (EHDV-8) emerged in Spain in autumn 2022. In this study, we aimed to (1) characterize the clinical and lesional presentation of EHDV infection in European red deer (Cervus elaphus), and (2) study the spatial spread of the virus in wild ruminants in Spain after its introduction, in 2022/2023. We confirmed EHDV infection in two clinically compatible sick red deer by PCR and detection of anti-EHDV specific antibodies. EHDV infection occurred in red deer with hyperacute to acute clinical signs and lesions associated to vascular changes leading to death of the animals. Partial sequences of variable segment 2 (VP2) and segment 5 (NS1) genes of the detected viruses had >99% nucleotide identity with EHDV-8 sequences from Tunisia and Italy. In a cross-sectional serological study of EHDV in 592 wild ruminants, mainly red deer (n=578), in southwestern Spain, we detected anti-EHDV antibodies in 37 of 592 samples (6.3%; 95% confidence interval: 4.3-8.2), all from red deer and from the localities where clinical cases of EHD were confirmed in red deer. We conclude that EHDV-8 infection causes severe EHD in European red deer. The serosurvey revealed a limited spread of EHDV-8 in Spanish wild ruminant populations in the first year of virus detection in Spain.
Topics: Animals; Deer; Cross-Sectional Studies; Spain; Reoviridae Infections; Ceratopogonidae; Ruminants; Hemorrhagic Disease Virus, Epizootic
PubMed: 38569324
DOI: 10.1016/j.vetmic.2024.110069 -
Viruses Mar 2024The African horse sickness virus (AHSV) belongs to the Genus Orbivirus, family Sedoreoviridae, and nine serotypes of the virus have been described to date. The AHSV...
Development and Validation of Three Triplex Real-Time RT-PCR Assays for Typing African Horse Sickness Virus: Utility for Disease Control and Other Laboratory Applications.
The African horse sickness virus (AHSV) belongs to the Genus Orbivirus, family Sedoreoviridae, and nine serotypes of the virus have been described to date. The AHSV genome is composed of ten linear segments of double-stranded (ds) RNA, numbered in decreasing size order (Seg-1 to Seg-10). Genome segment 2 (Seg-2) encodes outer-capsid protein VP2, the most variable AHSV protein and the primary target for neutralizing antibodies. Consequently, Seg-2 determines the identity of the virus serotype. An African horse sickness (AHS) outbreak in an AHS-free status country requires identifying the serotype as soon as possible to implement a serotype-specific vaccination program. Considering that nowadays 'polyvalent live attenuated' is the only commercially available vaccination strategy to control the disease, field and vaccine strains of different serotypes could co-circulate. Additionally, in AHS-endemic countries, more than one serotype is often circulating at the same time. Therefore, a strategy to rapidly determine the virus serotype in an AHS-positive sample is strongly recommended in both epidemiological situations. The main objective of this study is to describe the development and validation of three triplex real-time RT-PCR (rRT-PCR) methods for rapid AHSV serotype detection. Samples from recent AHS outbreaks in Kenia (2015-2017), Thailand (2020), and Nigeria (2023), and from the AHS outbreak in Spain (1987-1990), were included in the study for the validation of these methods.
Topics: Animals; Horses; African Horse Sickness Virus; Reverse Transcriptase Polymerase Chain Reaction; African Horse Sickness; Orbivirus; Antibodies, Neutralizing; Viral Vaccines
PubMed: 38543834
DOI: 10.3390/v16030470 -
Viruses Feb 2024Epizootic hemorrhagic disease (EHD) is a non-contagious arthropod-transmitted viral disease and a World Organization for Animal Health (WOAH)-listed disease of domestic...
Epizootic hemorrhagic disease (EHD) is a non-contagious arthropod-transmitted viral disease and a World Organization for Animal Health (WOAH)-listed disease of domestic and wild ruminants since 2008. EHDV is transmitted among susceptible animals by a few species of midges of genus . During the fall of 2021, a large outbreak caused by the epizootic hemorrhagic disease virus (EHDV), identified as serotype 8, was reported in Tunisian dairy and beef farms with Bluetongue virus (BTV)-like clinical signs. The disease was detected later in the south of Italy, in Spain, in Portugal and, more recently, in France, where it caused severe infections in cattle. This was the first evidence of EHDV-8 circulation outside Australia since 1982. In this study, we analyzed the epidemiological situation of the 2021-2022 EHDV outbreaks reported in Tunisia, providing a detailed description of the spatiotemporal evolution of the disease. We attempted to identify the eco-climatic factors associated with infected areas using generalized linear models (GLMs). Our results demonstrated that environmental factors mostly associated with the presence of , such as digital elevation model (DEM), slope, normalized difference vegetation index (NDVI), and night-time land surface temperature (NLST)) were by far the most explanatory variables for EHD repartition cases in Tunisia that may have consequences in neighboring countries, both in Africa and Europe through the spread of infected vectors. The risk maps elaborated could be useful for disease control and prevention strategies.
Topics: Cattle; Animals; Reoviridae Infections; Hemorrhagic Disease Virus, Epizootic; Serogroup; Tunisia; Ruminants; Animal Diseases; Ceratopogonidae; Bluetongue virus
PubMed: 38543728
DOI: 10.3390/v16030362 -
International Journal of Molecular... Mar 2024Kemerovo virus (KEMV) is a tick-borne orbivirus transmitted by ticks of the genus . Previous animal experimentation studies with orbiviruses, in particular the...
Kemerovo virus (KEMV) is a tick-borne orbivirus transmitted by ticks of the genus . Previous animal experimentation studies with orbiviruses, in particular the interferon receptor double knock-out (IFNAR) mouse model, did not indicate bias that is related to age or sex. We endeavoured to assess the effect of serial and alternated passages of KEMV in mammalian or cells on virus replication and potential virulence in male or female IFNAR mice, with important age differences: younger males (4-5 months old), older males (14-15 months old), and old females (14-15 months old). After 30 serial passages in mammalian or tick cells, or alternated passages in the two cell types, older female mice which were inoculated with the resulting virus strains were the first to show clinical signs and die. Younger males behaved differently from older males whether they were inoculated with the parental strain of KEMV or with any of the cell culture-passaged strains. The groups of male and female mice inoculated with the mammalian cell culture-adapted KEMV showed the lowest viraemia. While older female and younger male mice died by day 6 post-inoculation, surprisingly, the older males survived until the end of the experiment, which lasted 10 days. RNA extracted from blood and organs of the various mice was tested by probe-based KEMV real-time RT-PCR. Ct values of the RNA extracts were comparable between older females and younger males, while the values for older males were >5 Ct units higher for the various organs, indicating lower levels of replication. It is noteworthy that the hearts of the old males were the only organs that were negative for KEMV RNA. These results suggest, for the first time, an intriguing age- and sex-related bias for an orbivirus in this animal model. Changes in the amino acid sequence of the RNA-dependent RNA polymerase of Kemerovo virus, derived from the first serial passage in cells (KEMV Ps.IRE1), were identified in the vicinity of the active polymerase site. This finding suggests that selection of a subpopulation of KEMV with better replication fitness in tick cells occurred.
Topics: Animals; Female; Male; Mice; Amino Acid Sequence; Cell Culture Techniques; Ixodes; Mammals; Orbivirus; RNA, Viral
PubMed: 38542150
DOI: 10.3390/ijms25063177 -
MSphere Apr 2024Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in...
Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in different types of vertebrate and mosquito cells, with its neutralizing antibodies detected in cattle and goats. However, despite being isolated from midges and mosquitoes, there has been a notable absence of systematic studies on its vector competence. Thus, in this study, and were reared in the laboratory to measure vector susceptibility through blood-feeding infection. Furthermore, RNA sequencing was used to examine the overall alterations in the transcriptome following TIBOV infection. The results revealed that exhibited a high susceptibility to TIBOV compared to . Effective replication of the virus in midguts occurred when the blood-feeding titer of TIBOV exceeded 10 plaque-forming units mL. Nevertheless, only a few TIBOV RNA-positive samples were detected in the saliva of and , suggesting that these mosquito species may not be the primary vectors for TIBOV. Moreover, at 2 dpi of TIBOV, numerous antimicrobial peptides downstream of the Toll and Imd signaling pathways were significantly downregulated in , indicating that TIBOV suppressed mosquitos' defense to survive in the vector at an early stage. Subsequently, the stress-activated protein kinase JNK, a crucial component of the MAPK signaling pathway, exhibited significant upregulation. Certain genes were also enriched in the MAPK signaling pathway in TIBOV-infected at 7 dpi.IMPORTANCETibet orbivirus (TIBOV) is an understudied arbovirus of the genus . Our study is the first-ever attempt to assess the vector susceptibility of this virus in two important mosquito vectors, and . Additionally, we present transcriptome data detailing the interaction between TIBOV and the immune system of , which expands the knowledge about orbivirus infection and its interaction with mosquitoes.
Topics: Animals; Aedes; Culex; Mosquito Vectors; Orbivirus; Female; Virus Replication; Saliva; Transcriptome; Tibet
PubMed: 38530016
DOI: 10.1128/msphere.00062-24