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The emergence and circulation of duck reovirus have caused severe threats to domestic waterfowl production because of the lethal infections they cause in ducks and geese. However, the evolution of circulating duck reoviruses and their replication and pathogenicity in domestic birds have not been fully investigated. In this study, we identified and isolated six duck reoviruses from clinical samples of sick or deceased farmed ducks and geese and sequenced their full genomes. Phylogenetic analysis revealed the evolutionary landscape of duck reoviruses and the complex reassortment of these circulating viruses with avian orthoreovirus and Muscovy duck reovirus. Animal infection studies revealed differences in the replication and pathogenicity of the reoviruses identified in this study in ducks, geese and chickens. Lethal infection with highly pathogenic viruses causes severe focal necrosis and hemorrhage in the liver, spleen, bursa of Fabricius and thymus, resulting in high mortality in inoculated birds. Importantly, chickens are susceptible to circulating duck reovirus, highlighting the potential risk of duck reovirus infection in chickens. Our study revealed the evolution, pathogenicity and potential cross-species transmission risk of duck reoviruses, further emphasizing the importance of continued and systemic surveillance at the interface of domestic waterfowl and chickens. [ABSTRACT FROM AUTHOR]

Heart and skeletal muscle inflammation (HSMI) is a significant disease affecting Atlantic salmon (Salmo salar) production in Norway but has had limited impact to production in North America. The causative agent of HSMI is piscine orthoreovirus genotype 1 (PRV-1), and disease variation between regions is suggested to be at least partially driven by genetic variation of the virus. Using controlled laboratory injection challenges, we corroborate variations in disease outcomes for three PRV-1 isolates (PRV-1a from the eastern Pacific, PRV-1a from the western Atlantic, and PRV-1b from the Norwegian sea); however, virus replication dynamics, host recognition, and PRV-1-associated heart inflammation were also discrete relative to the Atlantic salmon stock challenged, irrespective of the viral isolate used. Specifically, New Brunswick Tobique River Atlantic salmon had less (p < 0.01) heart inflammation relative to Mowi-McConnell Atlantic salmon of Western Canada which, in turn, had less (p < 0.01) heart inflammation than Mowi Atlantic salmon of Scotland when cumulatively considering challenges using all three PRV-1 isolates. These data indicate that the presence of PRV-1a or PRV-1b alone is not sufficient to reliably predict disease and highlights at least one potential mechanism (host genotype) for reducing HSMI disease severity. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of global citriculture. In the Americas and in Asia, D. citri vectors the phloem-limited bacterium, Candidatus Liberibacter asiaticus (CLas), which causes the fatal citrus disease huanglongbing, or citrus greening. Cell lines derived from D. citri can provide insight into both the basic biology of this pest and D. citri-associated pathogens including CLas. We previously identified CLG#2 as the optimal medium for long-term growth of D. citri primary cell cultures. Here we report on the establishment and characterization of three continuous D. citri cell lines, Dici1, Dici3, and Dici5, that have been passaged for > 40 times. Based on morphological and transcriptomic data, the Dici1 and Dici3 cell lines include undifferentiated and neurogenic progenitor cells. Dici1 and Dici5 are infected with Wolbachia. Both Dici1 and Dici5 are infected with D. citri reovirus, and Dici5 is also infected with D. citri-associated C virus. Dici3 is free of both Wolbachia and virus infection. These cell lines provide an ideal platform for the study of inter-microbial relationships as well as microbe interaction with host insect cells. [ABSTRACT FROM AUTHOR]

The European grapevine moth (Lobesia botrana) poses a significant threat to vineyards worldwide, causing extensive economic losses. While its ecological interactions and control strategies have been well studied, its associated viral diversity remains unexplored. Here, we employ high-throughput sequencing data mining to comprehensively characterize the L. botrana virome, revealing novel and diverse RNA viruses. We characterized four new viral members belonging to distinct families, with evolutionary cues of cypoviruses (Reoviridae), sobemo-like viruses (Solemoviridae), phasmaviruses (Phasmaviridae), and carmotetraviruses (Carmotetraviridae). Phylogenetic analysis of the cypoviruses places them within the genus in affinity with other moth viruses. The bi-segmented and highly divergent sobemo-like virus showed a distinctive evolutionary trajectory of its encoding proteins at the periphery of recently reported invertebrate Sobelivirales. Notably, the presence of a novel phasmavirus, typically associated with mosquitoes, expands the known host range and diversity of this family to moths. Furthermore, the identification of a carmotetravirus branching in the same cluster as the Providence virus, a lepidopteran virus which replicates in plants, raises questions regarding the biological significance of this moth virus to the grapevine host. We further explored viral sequences in several publicly available transcriptomic datasets of the moth, indicating potential prevalence across distinct conditions. These results underscore the existence of a complex virome within L. botrana and lay the foundation for future studies investigating the ecological roles, evolutionary dynamics, and potential biocontrol applications of these viruses in the L. botrana–vineyard ecosystem. [ABSTRACT FROM AUTHOR]

Chinese rice‐field eels rhabdovirus (CrERV) causes haemorrhagic disease in Chinese rice‐field eels (Monopterus albus), leading to significant mortality and economic losses. Sensitive detection of CrERV nucleic acids is essential to control the spread of this pathogen and to treat infected individuals. Herein, we developed an efficient and sensitive droplet digital PCR (ddPCR) method to rapidly detect and quantify CrERV. The ddPCR assay optimal conditions were an annealing temperature of 53°C, and primer and probe concentrations of 0.5 and 0.25 μM, respectively. The assay had a diagnostic sensitivity of 0.23 copies/μL, and was highly specific, showing no cross reactivity with other viruses (infectious haematopoietic necrosis virus, grass carp reovirus, spring viremia of carp virus, largemouth bass ranavirus, carp edema virus, Chinese giant salamander iridovirus, and white spot syndrome virus). Real‐time quantitative PCR testing of 30 Chinese rice‐field eels samples detected CrERV in 7 samples (23.3%), whereas ddPCR detected CrERV in 12 samples (40%), demonstrating its higher sensitivity. Thus, ddPCR represents an advanced method to absolutely quantify CrERV in infected fish with low virus concentrations, providing a valuable tool to manage the spread and impact of CrERV. [ABSTRACT FROM AUTHOR]

Copyright of Kocatepe Veterinary Journal / Kocatepe Veteriner Dergisi is the property of Afyon Kocatepe University, Faculty of Veterinary Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pangolins have been found to carry severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)‐related coronaviruses. In light of this discovery, interest has been piqued in viromes of these heavily trafficked wild animals. In this study, we performed viral metagenomic sequencing to explore viromes of both confiscated dead pangolins and captive healthy pangolins. Sequence reads of vertebrate‐associated viruses in Herpesviridae, Retroviridae, Iridoviridae, Reoviridae, Arenaviridae, and Flaviviridae were detected in confiscated dead pangolins. A novel rotavirus (RV) (Reoviridae), showing a high degree of genetic similarity to the RV species D (RVD) that was previously unreported in mammals, was further confirmed by using reverse transcription‐polymerase chain reaction (RT‐PCR) and Sanger sequencing. Three out of 18 samples from the confiscated dead pangolins were positive for genomic sequences of the novel RV. Importantly, sequence alignments and phylogenetic analyses demonstrated that these RV strains genetically belonged to the RVD. Nevertheless, these novel RVD strains were divergent from known RVD strains that have been found only in Avian. They formed a separate genetic cluster. Five serial passages were attempted to isolate the RV, but no live virus was obtained. In addition, fecal samples were collected from healthy pangolins (n = 41) in our institution and screened for RVs by viral metagenomic sequencing and RT‐PCR. In these fecal samples, neither species D nor previously identified species A RVs were detected. This study reported RVDs in pangolin samples for the first time to our knowledge. Identifiability disagreements between wild and captive pangolins highlight the need for further exploration into pangolin viruses to better understand their emergence and transmission potential. [ABSTRACT FROM AUTHOR]

Since 2020, a novel goose-derived reovirus, characterized by goose hemorrhagic hepatitis, has emerged in the goose breeding industry of Guangdong province, China, leading to significant economic losses in the poultry sector. To study the genetic variation of novel goose reovirus (NGRV) in Guangdong province, this experiment utilized goose embryonic fibroblast cells for virus isolation. RT-PCR was conducted to identify, amplify, clone, and sequence the complete genome of the NGRV isolated from Zhaoqing. The genomic sequences were compared with reference strains to construct a phylogenetic tree. Moreover, animal pathogenicity, excretion patterns, and pathological sections were examined. The results showed that liver and spleen samples from geese suspected of NGRV infection were used for isolation, resulting in the identification of a reovirus presumed to originate from geese, designated as GD218. In terms of genomic structure and sequence homology, GD218 closely resembles the novel duck reovirus, differing significantly from earlier isolated NDRV strains (J18, NP03, SD12, etc.) in genetic composition (nt: 80.6–97.9%, aa: 94.3–98.9%). However, it is similar to strains isolated after 2018, such as XT18, SY, QR, YL, LY20, etc. (nt: 95.3–98.9%, aa: 98.6–99.7%). Therefore, based on phylogenetic analysis, GD218 is hypothesized to be a novel type of goose-origin reovirus homologous to the novel duck reovirus. [ABSTRACT FROM AUTHOR]

Understanding of the physicochemical properties and functions of biomolecular condensates has rapidly advanced over the past decade. More recently, many RNA viruses have been shown to form cytoplasmic replication factories, or viroplasms, via phase separation of their components, akin to numerous cellular membraneless organelles. Notably, diverse viruses from the Reoviridae family containing 10-12 segmented double-stranded RNA genomes induce the formation of viroplasms in infected cells. Little is known about the inner workings of these membraneless cytoplasmic inclusions and how they may support stoichiometric RNA assembly in viruses with segmented RNA genomes, raising questions about the roles of phase separation in coordinating viral genome packaging. Here, we discuss how the molecular composition of viroplasms determines their properties, highlighting the interplay between RNA structure, RNA remodelling, and condensate self-organisation. Advancements in RNA structural probing and theoretical modelling of condensates can reveal the mechanisms through which these ribonucleoprotein complexes support the selective enrichment and stoichiometric assembly of distinct viral RNAs. [ABSTRACT FROM AUTHOR]

The life cycle of foot-and-mouth disease virus (FMDV) is tightly regulated by host cell lipid metabolism. In previous studies, we reported downregulated expression of stearoyl coenzyme A desaturase-1 (SCD1), a key enzyme of fatty acid metabolism, in BHK-VEC cells (a virus-negative cell line derived from BKH-21 cells with persistent FMDV infection) on comparing transcriptomic data for BHK-VEC and BHK-21 cells (Y. Yuan et al., Front Cell Infect Microbiol 12:940906, 2022, https://doi.org/10.3389/fcimb.2022.940906; L. Han et al., Vet Microbiol 263:109247, 2021, https://doi.org/10.1016/j.vetmic.2021.109247). In the present study, we identify that SCD1 regulates FMDV replication. SCD1 overexpression or exogenous addition of oleic acid (OA), a product of the enzymatic activity of SCD1, increased FMDV replication in both BHK-21 cells and SCD1-knockdown cells. Overexpression of SCD1 or exogenous addition of OA restored FMDV infection and replication in BHK-VEC cells, and OA also promoted FMDV replication in BHK-21 cells with persistent FMDV infection. SCD1 recruited the nonstructural FMDV protein 2C to a detergent-resistant membrane located in the perinuclear region of cells to form replication complexes. Inhibiting SCD1 enzyme activity resulted in a significantly decreased number of FMDV replication complexes with abnormal morphology. Inhibition of SCD1 activity also effectively decreased the replication of other RNA viruses such as respiratory enteric orphan virus-3-176, poliovirus-1, enterovirus 71, and vesicular stomatitis virus. Our results demonstrate that SCD1, as a key host regulator of RNA virus replication, is a potential target for developing novel drugs against infections by RNA viruses. [ABSTRACT FROM AUTHOR]

The purpose of this review is to present modern data on the correlations between viruses and celiac disease. Some viruses probably have crucial role in celiac disease pathogenesis according to the results of recent studies. However, the virus exposure itself does not lead to the development of autoimmune disease. Number of studies have demonstrated that there are several viruses that can cause celiac disease, and several activation pathways leading to food tolerance loss. Thus far, the role of some reoviruses strains has been proven in the development of celiac disease. Further research is needed for better understanding of the viruses role in the celiac disease development and to improve management and prevention of this disease.

A breeding colony of wild-origin eastern indigo snakes (EISs, Drymarchon couperi) that is part of a reintroduction program has been impacted by gastric cryptosporidiosis. Gastric cryptosporidiosis is an insidious disease of squamates caused by an apicomplexan protozoan, Cryptosporidium serpentis. Viral coinfections have been implicated as possible immunosuppressant agents that allow for disease progression and both adenovirus and reovirus have been implicated in allowing for the progression of gastric cryptosporidiosis during coinfection in other snake species. Molecular (PCR) screening for adenoviruses and reoviruses was performed for both C. serpentis-positive and C. serpentis-negative EIS within the breeding colony. No reoviruses were detected in the collection. Adenoviruses were present in 11/68 (16.2%) EISs evaluated, and there was no significant difference between C. serpentis-positive and C. serpentis-negative EISs (p = 0.196). There was no significant difference in adenovirus status between C. serpentis-positive EISs' lifespan (p = 0.191) or survival rates (p = 0.823). These findings suggest that the presence of the adenoviruses found in this study does not contribute to the formation or progression of gastric cryptosporidiosis in EISs. [ABSTRACT FROM AUTHOR]

Background: Rotaviruses have been widely reported and have a worldwide prevalence to be associated with diarrhea in humans but fewer studies abound on other mammalian species. Group A Rotavirus (RVA) are majorly responsible for causing acute gastroenteritis (AGE) in humans and animals. Methods: In the present study 150 diarrheic fecal samples from, piglets, pups and human infants (0-5 yr of age) were screened for the presence of rotaviruses by lateral flow assay, VP6-based RT-PCR assay and phylogenetic analysis. Result: A total of 13/150 (8.6%) fecal samples were found positive by lateral flow assay. Out of 50 diarrheic fecal samples each of human infants 4 (8.0%), pups, 03 (6.0%), piglet samples 6 (12.00%) showed the presence of rotavirus. All 13 positive fecal samples from piglets, pups and human infants were further screened for the detection of group A Rotavirus by VP6 gene-based RT-PCR assay. Of the samples tested, 13 (100.00%) samples were found positive for Rotavirus. The sequences of VP6 gene amplified from piglet, pups and human infants were subjected to phylogenetic analysis. The phylogenetic analysis showed that there is not much sequence variation between rotavirus from human infant and piglet. It showed more identity with Homo sapiens and Bos taurus which indicated the possibility of zoonotic transmission. [ABSTRACT FROM AUTHOR]

Coltiviruses, belonging to the genus Coltivirus within the family Spinareoviridae, are predominantly tick-borne viruses. Some of these species have been implicated in human diseases; however, their diversity, geographical distribution, and evolutionary dynamics remain inadequately. Therefore, this study was undertaken to explore the phylogenetic evolution of coltiviruses and related viruses. Our results revealed the detection of novel coltivirus-related sequences in adult female Haemaphysalis megaspinosa ticks collected from Kanagawa Prefecture, Japan. Molecular phylogenetic analysis revealed a close association between the sequences and the genome sequences of known coltivirus-related viruses, namely Qinghe tick reovirus and Fennes virus. The putative coltivirus-related virus was tentatively designated the Nakatsu tick virus. This study provides insights into the phylogenetic evolution of coltiviruses and related viruses. [ABSTRACT FROM AUTHOR]

Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014–2018, for five viral infections that are prevalent in global salmonid aquaculture. Over 90% of the escapees were infected with one or more viruses. Overall prevalences were: 75.7% for piscine orthoreovirus (PRV‐1), 43.6% for salmonid alphavirus (SAV), 31.2% for piscine myocarditis virus (PMCV), 1.2% for infectious pancreatic necrosis virus (IPNV) and 0.4% for salmon anaemia virus (ISAV). A significantly higher prevalence of PMCV infection was observed in immature compared to mature individuals. The prevalence of both SAV and PMCV infections was higher in fish determined by fatty acid profiling to be 'recent' as opposed to 'early' escapees that had been in the wild for a longer period of time. This is the first study to establish a time‐series of viral infection status of escapees entering a river with a native salmon population. Our results demonstrate that farmed escapees represent a continuous source of infectious agents which could potentially be transmitted to wild fish populations. [ABSTRACT FROM AUTHOR]

Tumor hypoxia plays a crucial role in driving cancer progression and fostering resistance to therapies by contributing significantly to chemoresistance, radioresistance, angiogenesis, invasiveness, metastasis, altered cell metabolism, and genomic instability. Despite the challenges encountered in therapeutically addressing tumor hypoxia with conventional drugs, a noteworthy alternative has emerged through the utilization of anaerobic oncolytic bacteria. These bacteria exhibit a preference for accumulating and proliferating within the hypoxic regions of tumors, where they can initiate robust antitumor effects and immune responses. Through simple genetic manipulation or sophisticated synthetic bioengineering, these bacteria can be further optimized to improve safety and antitumor activities, or they can be combined synergistically with chemotherapies, radiation, or other immunotherapies. In this review, we explore the potential benefits and challenges associated with this innovative anticancer approach, addressing issues related to clinical translation, particularly as several strains have progressed to clinical evaluation. [ABSTRACT FROM AUTHOR]

This review article focuses on avian reovirus (ARV) regarding the virus characters, susceptibility and transmission, the different clinical forms, laboratory diagnosis, and preventive measures. Despite most of ARV strains are abundant and innocuous, they are responsible for many diseases conditions in poultry industry. The pathogenic ARV strains induce great economic losses including growth retardation, increasing culling rate, high mortality rate, immunosuppression, and increasing the carcass rejection rate at processing. Strains of ARV belong to the family Reoviridae and genus Orthoreovirus are non-enveloped and double-stranded RNA. Almost all of avian species are susceptible to infection especially at young ages. The virus rapidly spreads among flocks via the horizontal, vertical, and mechanical routes. The infection with ARV is mainly associated with arthritis/tenosynovitis and runting stunting syndrome. However, other clinical pictures such as gastroenteritis, hepatitis, myocarditis, and respiratory disease are also related to ARV infections. Laboratory diagnosis is based on isolation and characterization of the virus using conventional methods of detection. Nevertheless, recent molecular techniques are also regarded as suitable for the efficient diagnosis. Serological detection of specific ARV antibodies have been also applied. Adoption of hygienic measures and vaccination with live or inactivated vaccines are the most suitable methods for the prevention of field ARV infections. [ABSTRACT FROM AUTHOR]

Intravesical treatment using either reovirus or natural killer (NK) cells serves as an efficient strategy for the treatment of bladder cancer cells (BCCs); however, corresponding monotherapies have often shown modest cytotoxicity. The potential of a locoregional combination using high-dose reovirus and NK cell therapy in an intravesical approach has not yet been studied. In this study, we evaluated the effectiveness of reoviruses and expanded NK cells (eNK) as potential strategies for the treatment of bladder cancer. The anti-tumor effects of mono-treatment with reovirus type 3 Dearing strain (RC402 and RP116) and in combination with interleukin (IL)-18/-21-pretreated eNK cells were investigated on BCC lines (5637, HT-1376, and 253J-BV) using intravesical therapy to simulate in vitro model. RP116 and IL-18/-21-pretreated eNK cells exhibited effective cytotoxicity against grade 1 carcinoma (5637 cells) when used alone, but not against HT-1376 (grade 2 carcinoma) and 253J-BV cells (derived from a metastatic site). Notably, combining RP116 with IL-18/-21-pretreated eNK cells displayed effective cytotoxicity against both HT-1376 and 253J-BV cells. Our findings underscore the potential of a combination therapy using reoviruses and NK cells as a promising strategy for treating bladder cancer. [ABSTRACT FROM AUTHOR]

Tibet orbivirus (TIBOV) was first isolated from Anopheles maculatus 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 Culex 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 × 10-3 nucleotide substitutions per site per year (s/s/y) (95% HPD: 3.07 × 10-5, 9.63 × 10-3), which is similar to that of the bluetongue virus (BTV), also in the Orbivirus 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. [ABSTRACT FROM AUTHOR]

The Chinese tree shrew (Tupaia belangeri chinensis), a member of the mammalian order Scandentia, exhibits considerable similarities with primates, including humans, in aspects of its nervous, immune, and metabolic systems. These similarities have established the tree shrew as a promising experimental model for biomedical research on cancer, infectious diseases, metabolic disorders, and mental health conditions. Herein, we used metatranscriptomic sequencing to analyze plasma, as well as oral and anal swab samples, from 105 healthy asymptomatic tree shrews to identify the presence of potential zoonotic viruses. In total, eight mammalian viruses with complete genomes were identified, belonging to six viral families, including Flaviviridae, Hepeviridae, Parvovirinae, Picornaviridae, Sedoreoviridae, and Spinareoviridae. Notably, the presence of rotavirus was recorded in tree shrews for the first time. Three viruses — hepacivirus 1, parvovirus, and picornavirus — exhibited low genetic similarity (<70%) with previously reported viruses at the whole-genome scale, indicating novelty. Conversely, three other viruses — hepacivirus 2, hepatovirus A and hepevirus — exhibited high similarity (>94%) to known viral strains. Phylogenetic analyses also revealed that the rotavirus and mammalian orthoreovirus identified in this study may be novel reassortants. These findings provide insights into the diverse viral spectrum present in captive Chinese tree shrews, highlighting the necessity for further research into their potential for crossspecies transmission. [ABSTRACT FROM AUTHOR]

This article discusses the role of RNA recombination in preventing the emergence or reemergence of Senecavirus A (SVA), a virus that affects pigs. It explains the genomic structure of SVA and how it evolves through selective pressure and intra-species recombination. The article emphasizes the importance of RNA recombination in preventing emerging and reemerging diseases and highlights the potential risks and consequences of SVA recombinants. The authors suggest continuous detection and surveillance for SVA recombination to prevent its emergence or reemergence. This document is a list of references for scientific articles related to Senecavirus A, providing valuable information for researchers studying the virus and its impact on pig populations. [Extracted from the article]

Summary: Most plant reoviruses are phloem‐limited, but the mechanism has remained unknown for more than half a century. Southern rice black‐streaked dwarf virus (Fijivirus, Reoviridae) causes phloem‐derived tumors, where its virions, genomes, and proteins accumulate, and it was used as a model to explore how its host plant limits the virus within its phloem.High‐throughput volume electron microscopy revealed that only sieve plate pores and flexible gateways rather than plasmodesmata had a sufficiently large size exclusion limit (SEL) to accommodate virions and potentially serve as pathways of virion movement.The large SEL gateways were enriched within the proliferated sieve element (SE) layers of tumors. The lack of such connections out of the SE‐enriched regions of tumors defined a size‐dependent physical barrier to high flux transportation of virions.A working model is proposed to demonstrate the mechanism underlying limitation of virus within phloem. [ABSTRACT FROM AUTHOR]

A variety of illnesses, including arthritis, tenosynovitis, stunted growth, and malabsorption syndrome, are caused by Avian Reoviruses (ARVs), which have become more prevalent in Egypt during recent years and resulted in significant economic losses. This study investigated 27 suspected samples collected from 14 broiler breeders and 13 broilers suffering from immunosuppression, decreased body weight, and diarrhea. Fourteen samples tested positive based on RT-PCR, and the virus could be isolated from ten samples in Specific Pathogen Free (SPF) embryonated chicken eggs. Ten isolates were subjected to molecular and genetic analysis of the S1 gene (sigma C) and S2 gene (sigma A). The amino acid identity of the S1 gene revealed that these viruses are closely related to the viruses that were identified in Israel during 2020 (91.8%-97.2% identity) and belonged to the genetic cluster 5 (genotype 5), which also includes some viruses that are circulating in the United States and Canada. They also showed weak similarity (48.9%-50.2%) with the available vaccine strains in the Egyptian field that belong to cluster 1, genotype 1. The S2 gene showed amino acid homology of 91.7%-98.2% with the current vaccine used in Egypt. However, the Egy-Reo-7-2021 virus had the lowest similarity (84.2%-87.6%) to the available vaccine. It is hypothesized that the difference between field and vaccine strains may have contributed to the failure of current vaccinations to produce protective immunity against current ARV strains circulated in Egypt, which made the disease a problem to the poultry industry. Developing homologous vaccines and evaluating their potency and efficacy are required in Egypt. [ABSTRACT FROM AUTHOR]

Nearly 70% of plant virus species are transmitted by specific insect vectors, and this vector transmission is key for disease outbreaks. Understanding the mechanism by which the insects transmit the specific virus is critical for predicting and controlling the viral disease. Autophagy in insect vectors is activated through various pathways depending on the insect–virus combination after the insect acquires the plant reovirus. Plant reoviruses not only escape degradation by blocking fusion of autophagosomes and lysosomes, but also use unfused autophagosomes to assemble new virions or cross multiple membrane barriers in the insect. Entry of a plant reovirus into the insect vector can activate mitophagy to degrade damaged mitochondria to avoid mitochondria-dependent apoptosis, providing an optimal intracellular environment for persistent virus survival. Plant reoviruses, transmitted only by insect vectors, seriously threaten global cereal production. Understanding how insect vectors efficiently transmit the viruses is key to controlling the viral diseases. Autophagy commonly plays important roles in plant host defense against virus infection, but recent studies have shown that plant reoviruses can hijack the autophagy pathway in insect cells to enable their persistence in the insect and continued transmission to plants. Here, we summarize and discuss new insights on viral activation, evasion, regulation, and manipulation of autophagy within the insect vectors and the role of autophagy in virus survival in insect vectors. Deeper knowledge of the functions of autophagy in vectors may lead to novel strategies for blocking transmission of insect-borne plant viruses. [ABSTRACT FROM AUTHOR]

Avian reovirus (ARV) infection is prevalent in farmed poultry and causes viral arthritis and severe immunosuppression. The spleen plays a very important part in protecting hosts against infectious pathogens. In this research, transcriptome and translatome sequencing technology were combined to investigate the mechanisms of transcriptional and translational regulation in the spleen after ARV infection. On a genome-wide scale, ARV infection can significantly reduce the translation efficiency (TE) of splenic genes. Differentially expressed translational efficiency genes (DTEGs) were identified, including 15 upregulated DTEGs and 396 downregulated DTEGs. These DTEGs were mainly enriched in immune regulation signaling pathways, which indicates that ARV infection reduces the innate immune response in the spleen. In addition, combined analyses revealed that the innate immune response involves the effects of transcriptional and translational regulation. Moreover, we discovered the key gene IL4I1, the most significantly upregulated gene at both the transcriptional and translational levels. Further studies in DF1 cells showed that overexpression of IL4I1 could inhibit the replication of ARV, while inhibiting the expression of endogenous IL4I1 with siRNA promoted the replication of ARV. Overexpression of IL4I1 significantly downregulated the mRNA expression of IFN-β, LGP2, TBK1 and NF-κB; however, the expression of these genes was significantly upregulated after inhibition of IL4I1, suggesting that IL4I1 may be a negative feedback effect of innate immune signaling pathways. In addition, there may be an interaction between IL4I1 and ARV σA protein, and we speculate that the IL4I1 protein plays a regulatory role by interacting with the σA protein. This study not only provides a new perspective on the regulatory mechanisms of the innate immune response after ARV infection but also enriches the knowledge of the host defense mechanisms against ARV invasion and the outcome of ARV evasion of the host's innate immune response. [ABSTRACT FROM AUTHOR]

Simple Summary: A genomic epidemiological study was conducted to describe the genetic diversity within turkey reoviruses circulating in Hungary. Phylogenetic analyses confirmed that turkey reoviruses comprise a well determined genetic clade; however, evidence shows occasional genetic interaction between turkey reoviruses and reoviruses of other avian species. A better understanding of the source and the route of reovirus infections in the field requires extended sampling of strains from additional geographic areas and from different phases of turkey production. Reovirus infections in turkeys are associated with arthritis and lameness. Viral genome sequence data are scarce, which makes an accurate description of the viral evolution and epidemiology difficult. In this study, we isolated and characterized turkey reoviruses from Hungary. The isolates were identified in 2016; these isolates were compared with earlier Hungarian turkey reovirus strains and turkey reoviruses isolated in the 2010s in the United States. Gene-wise sequence and phylogenetic analyses identified the cell-receptor binding protein and the main neutralization antigen, σC, to be the most conserved. The most genetically diverse gene was another surface antigen coding gene, μB. This gene was shown to undergo frequent reassortment among chicken and turkey origin reoviruses. Additional reassortment events were found primarily within members of the homologous turkey reovirus clade. Our data showed evidence for low variability among strains isolated from independent outbreaks, a finding that suggests a common source of turkey reoviruses in Hungarian turkey flocks. Given that commercial vaccines are not available, identification of the source of these founder virus strains would permit a more efficient prevention of disease outbreaks before young birds are settled to fattening facilities. [ABSTRACT FROM AUTHOR]

The aim of this review is to provide a comprehensive overview about the link between viruses and celiac disease. A systematic search on PubMed, Embase, and Scopus was conducted on March 07, 2023. The reviewers independently selected the articles and chose which articles to include. The review is a textual systemic review, and all relevant articles were included based on title and abstract. If there was a disagreement between the reviewers, they came to a consensus during deliberation sessions. A total of 178 articles were selected for the review and read in full; only part of them was retained. We found studies between celiac disease and 12 different viruses. Some of the studies were done only on small groups. Most studies were on pediatric population. Evidence for an association was found with several viruses (trigger or protective). It seems that only a part of the viruses could induce the disease. Several points are important to keep in mind: firstly, simple mimicry or that the virus induces a high level of TGA is not sufficient to promote the disease. Secondly, inflammatory background is necessary to induce CD with virus. Thirdly, IFN type 1 seems to have an important role. Some of the viruses are potential or known triggers like enteroviruses, rotaviruses, reoviruses, and influenza. Further studies are needed to better understand the role of viruses in celiac disease to better treat and prevent the disease. [ABSTRACT FROM AUTHOR]

Highly pathogenic avian influenza (HPAI) H5Nx viruses can cause neurological complications in many mammalian species, including humans. Neurological disease induced by HPAI H5Nx viruses in mammals can manifest without clinical respiratory disease. HPAI H5Nx viruses are more neuropathogenic than other influenza A viruses in mammals. Severe neurological disease in mammals is related to the neuroinvasive and neurotropic potential of HPAI H5Nx viruses. Cranial nerves, especially the olfactory nerve, are important routes of neuroinvasion for HPAI H5Nx viruses. HPAI H5Nx viruses have a broad neurotropic potential and can efficiently infect and replicate in various CNS cell types. Vaccination and/or antiviral therapy might in part prevent neuroinvasion and neurological disease following HPAI H5Nx virus infection, although comprehensive studies in this area are lacking. Circulation of highly pathogenic avian influenza (HPAI) H5Nx viruses of the A/Goose/Guangdong/1/96 lineage in birds regularly causes infections of mammals, including humans. In many mammalian species, infections are associated with severe neurological disease, a unique feature of HPAI H5Nx viruses compared with other influenza A viruses. Here, we provide an overview of the neuropathogenesis of HPAI H5Nx virus infection in mammals, centered on three aspects: neuroinvasion, neurotropism, and neurovirulence. We focus on in vitro studies, as well as studies on naturally or experimentally infected mammals. Additionally, we discuss the contribution of viral factors to the neuropathogenesis of HPAI H5Nx virus infections and the efficacy of intervention strategies to prevent neuroinvasion or the development of neurological disease. [ABSTRACT FROM AUTHOR]

Background: Bats are recognized as reservoir species for multiple viruses. However, little is known on bats' health and mortality. Thus, this study aimed to investigate the main causes of death of bats from Turin province (North-western Italy) and to describe gross and histopathological lesions potentially associated with the presence of selected bat viruses. Results: A total of 71 bats belonging to 9 different species of the families Vespertilionidae and Molossidae were necropsied and samples of the main organs were submitted to histopathological examination. Also, aliquots of the small intestine, liver, spleen, lung, and brain were collected and submitted to biomolecular investigation for the identification of Coronaviridae, Poxviridae, Reoviridae (Mammalian orthoreovirus species), Rhabdoviridae (Vaprio ledantevirus and Lyssavirus species) and Kobuvirus. The majority of bats died from traumatic lesions due to unknown trauma or predation (n = 40/71, 56.3%), followed by emaciation (n = 13/71,18.3%). The main observed gross lesions were patagium and skin lesions (n = 23/71, 32.4%), forelimbs fractures (n = 15/71, 21.1%) and gastric distension (n = 10/71,14.1%). Histologically, the main lesions consisted of lymphoplasmacytic pneumonia (n = 24/71, 33.8%), skin/patagium dermatitis (n = 23/71, 32.4%), liver steatosis and hepatitis (n = 12, 16.9%), and white pulp depletion in the spleen (n = 7/71, 9.8%). Regarding emergent bat viruses, only poxvirus (n = 2, 2.8%) and orthoreovirus (n = 12/71, 16.9%) were detected in a low percentage of bats. Conclusions: Trauma is the main lesion observed in bats collected in Turin province (North-western Italy) associated with forelimb fractures and the detected viral positivity rate seems to suggest that they did not represent a threat for human health. [ABSTRACT FROM AUTHOR]

Mammalian orthoreoviruses (reoviruses) infect many mammals and provide a safe model to study enteric viruses. Knowledge of reoviruses is derived from prototypic lab strains, notably T1L and T3D. Based on these prototypic strains, reoviruses can efficiently utilize gut or lysosomal proteases for uncoating and penetration into host cytoplasm. To discover natural reovirus characteristics, we isolated four genetically diverse wastewater reovirus samples and compared their genetic and phenotypic characteristics to those of T1L/T3D. On L929 cells, the most commonly used model for reovirus studies, naturally derived reoviruses displayed lower fitness than T1L/T3D, evident from smaller plaques and higher relative particle-to-PFU ratios. In contrast to T1L/T3D, which are uncoated efficiently by lysosomal-mediated proteolysis, naturally derived reoviruses displayed poor uncoating kinetics. Exposure of naturally derived reoviruses to gut proteases led to rapid extracellular uncoating and significantly improved infectivity relative to T1L/T3D, indicating that wild reoviruses depended more on extracellular gut proteases. To discover if reovirus can adapt to new host proteases, naturally derived samples were passaged on L929 cells, and large and small plaqueforming isolates were evaluated. Larger plaque sizes correlate with faster intracellular uncoating. Whole-genome sequencing identified the outer capsid σ3 protein as the determinant of uncoating proficiency between wild reoviruses. Interestingly, mutations that permitted intracellular uncoating were found in 0.01% of the parental quasispecies, suggesting that variants with altered protease sensitivity were rapidly selected for during cell culture propagation. Altogether, these findings indicate that naturally circulating reoviruses are more reliant on gut proteases, but the genetic diversity of reovirus quasispecies bestows tremendous plasticity toward protease utility. IMPORTANCE Reoviruses infect many mammals and are widely studied as a model system for enteric viruses. However, most of our reovirus knowledge comes from laboratory strains maintained on immortalized L929 cells. Herein, we asked whether naturally circulating reoviruses possess the same genetic and phenotypic characteristics as laboratory strains. Naturally circulating reoviruses obtained from sewage were extremely diverse genetically. Moreover, sewage reoviruses exhibited poor fitness on L929 cells and relied heavily on gut proteases for viral uncoating and productive infection compared to laboratory strains. We then examined how naturally circulating reoviruses might adapt to cell culture conditions. Within three passages, virus isolates from the parental sewage population were selected, displaying improved fitness and intracellular uncoating in L929 cells. Remarkably, selected progeny clones were present at 0.01% of the parental population. Altogether, using reovirus as a model, our study demonstrates how the high genetic diversity of naturally circulating viruses results in rapid adaptation to new environments. [ABSTRACT FROM AUTHOR]

Whole-genome sequencing (WGS) is becoming an essential tool to characterize the genomes of avian reovirus (ARV), a viral disease of economic significance to poultry producers. The current strategies and procedures used to obtain the complete genome sequences of ARV isolates are not cost-effective because most of the genetic material data resulting from next-generation sequencing belong to the host and cannot be used to assemble the viral genome. The purpose of this study was to develop a workflow to enrich the ARV genomic content in a sample before subjecting it to next-generation sequencing (NGS). Herein, we compare four different ARV purification and enrichment approaches at the virion, RNA and cDNA levels to determine which treatment or treatment combination would provide a higher proportion of ARV-specific reads after WGS. Seven ARV isolates were subjected to different combinations of virion purification via ultracentrifugation in sucrose density gradient or Capto Core 700 resin with or without a subsequent Benzonase treatment, followed by a chicken rRNA depletion step after RNA extraction and a final ARV cDNA amplification step using a single-primer amplification assay. Our results show that the combination of Capto Core 700 resin, Chicken rRNA depletion and cDNA amplification is the most cost-effective strategy to obtain ARV whole genomes after short-read sequencing. [ABSTRACT FROM AUTHOR]

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick‐borne disease with high mortality in Eastern Asia. The disease is caused by the SFTS virus (SFTSV), also known as Dabie bandavirus, which has a segmented RNA genome consisting of L, M, and S segments. Previous studies have suggested differential viral virulence depending on the genotypes of SFTSV; however, the critical viral factor involved in the differential viral virulence is unknown. Here, we found a significant difference in viral replication in vitro and virulence in vivo between two Korean isolates belonging to the F and B genotypes, respectively. By generating viral reassortants using the two viral strains, we demonstrated that the L segment, which encodes viral RNA‐dependent RNA polymerase (RdRp), is responsible for the enhanced viral replication and virulence. Comparison of amino acid sequences and viral replication rates revealed a point variation, E251K, on the surface of RdRp to be the most significant determinant for the enhanced viral replication rate and in vivo virulence. The effect of the variation was further confirmed using recombinant SFTSV generated by reverse genetic engineering. Therefore, our results indicate that natural variations affecting the viral replicase activity could significantly contribute to the viral virulence of SFTSV. [ABSTRACT FROM AUTHOR]

Background: Understanding temporal and spatial dynamics of malaria transmission will help to inform effective interventions and strategies in regions approaching elimination. Parasite genomics are increasingly used to monitor epidemiologic trends, including assessing residual transmission across seasons and importation of malaria into these regions. Methods: In a low and seasonal transmission setting of southern Zambia, a total of 441 Plasmodium falciparum samples collected from 8 neighbouring health centres between 2012 and 2018 were genotyped using molecular inversion probes (MIPs n = 1793) targeting a total of 1832 neutral and geographically informative SNPs distributed across the parasite genome. After filtering for quality and missingness, 302 samples and 1410 SNPs were retained and used for downstream population genomic analyses. Results: The analyses revealed most (67%, n = 202) infections harboured one clone (monogenomic) with some variation at local level suggesting low, but heterogenous malaria transmission. Relatedness identity-by-descent (IBD) analysis revealed variable distribution of IBD segments across the genome and 6% of pairs were highly-related (IBD ≥ 0.25). Some of the highly-related parasite populations persisted across multiple seasons, suggesting that persistence of malaria in this low-transmission region is fueled by parasites "seeding" across the dry season. For recent years, clusters of clonal parasites were identified that were dissimilar to the general parasite population, suggesting parasite populations were increasingly fragmented at small spatial scales due to intensified control efforts. Clustering analysis using PCA and t-SNE showed a lack of substantial parasite population structure. Conclusion: Leveraging both genomic and epidemiological data provided comprehensive picture of fluctuations in parasite populations in this pre-elimination setting of southern Zambia over 7 years. [ABSTRACT FROM AUTHOR]

Simple Summary: Avian orthoreoviruses cause significant losses to the poultry industry worldwide. Reovirus-associated diseases in chickens are frequently reported even in vaccinated flocks due to the emergence and spread of novel strains. Herein we studied the genetic features of reovirus strains originating from parts of East-Central Europe. The isolated strains from the study area displayed large genetic variability and shared low genetic similarity with vaccine strains. These findings highlight the importance of immune pressure from vaccination in the epizootiology of reovirus infection in chickens. The concern that the vaccines currently used against Avian orthoreovirus (ARV) infections are less efficient in the field justifies the need for the close monitoring of circulating ARV strains. In this study, we collected necropsy samples from various chicken breeds and tested for ARV by virus isolation, RT-PCR assay and sequence analysis. ARVs were isolated from birds showing runting-stunting syndrome, uneven growth, lameness or increased mortality, with relative detection rates of 38%, 35%, 6% and 25%, respectively. Partial σC gene sequences were determined for nearly 90% of ARV isolates. The isolates could be classified into one of the major genetic clusters. Interestingly, cluster 2 and cluster 5 were isolated from vaccinated broiler breeders, while clusters 1 to 4 were isolated from unvaccinated broilers. The isolates shared less than 75% amino acid identities with the vaccine strains (range, 44.3–74.6%). This study reaffirms the global distribution of the major genetic clusters of ARVs in chicken. The diversity of ARV strains isolated from unvaccinated broilers was greater than those detected from vaccinated animals, however, the relative importance of passive and active immunity on the selection of novel strains in different chicken breeds needs to be better understood. [ABSTRACT FROM AUTHOR]

Vesicle-encapsulated nonenveloped viruses are a recently recognized alternate form of nonenveloped viruses that can avoid immune detection and potentially increase systemic transmission. Avian orthoreoviruses (ARVs) are the leading cause of various disease conditions among birds and poultry. However, whether ARVs use cellular vesicle trafficking routes for egress and cell-to-cell transmission is still poorly understood. We demonstrated that fusogenic ARV-infected quail cells generated small (~100 nm diameter) extracellular vesicles (EVs) that contained electron-dense material when observed by transmission electron microscope. Cryo-EM tomography indicated that these vesicles did not contain ARV virions or core particles, but the EV fractions of OptiPrep gradients did contain a small percent of the ARV virions released from cells. Western blotting of detergent-treated EVs revealed that soluble virus proteins and the fusogenic p10 FAST protein were contained within the EVs. Notably, virus particles mixed with the EVs were up to 50 times more infectious than virions alone. These results suggest that EVs and perhaps fusogenic FAST-EVs could contribute to ARV virulence. [ABSTRACT FROM AUTHOR]

This is the first viral metagenomic analysis of grapevine conducted in Mexico. During the summer of 2021, 48 plants displaying virus-like symptoms were sampled in Queretaro, an important grapevine-producing area of Mexico, and analyzed for the presence of viruses via high-throughput sequencing (HTS). The results of HTS were verified by real-time RT-PCR following a standardized testing scheme (Protocol 2010). Fourteen different viruses were identified, including grapevine asteroid mosaic-associated virus (GAMaV), grapevine Cabernet Sauvignon reovirus (GCSV), grapevine fanleaf virus (GFLV), grapevine fleck virus (GFkV), grapevine Pinot gris virus (GPGV), grapevine red globe virus (GRGV), grapevine rupestris stem pitting-associated virus (GRSPaV), grapevine rupestris vein feathering virus (GRVFV), grapevine Syrah virus 1 (GSyV-1), grapevine virus B (GVB), and grapevine leafroll-associated viruses 1, 2, 3, 4 (GLRaV1, 2, 3, 4). Additionally, divergent variants of GLRaV4 and GFkV, and a novel Enamovirus-like virus were discovered. This is the first report of GAMaV, GCSV, GLRaV4, GPGV, GRGV, GRVFV, and GSyV-1 infecting grapevines in Mexico; the impact of these pathogens on production is unknown. [ABSTRACT FROM AUTHOR]

This document is a memorial for Michael B. A. Oldstone, a renowned researcher in the field of infectious diseases and virology. Oldstone's interest in the subject began in junior high school and he went on to receive a medical degree in 1961. He conducted his research career at the Scripps Research Institute, focusing on the immune pathology of the lymphocytic choriomeningitis virus (LCMV). His work with LCMV led to important discoveries in viral pathogenesis and immunity, with implications for human diseases. Oldstone received numerous awards and honors for his contributions to the field and trained over 80 postdoctoral fellows. He was also committed to communicating biomedical science to the public and authored a book on the subject. [Extracted from the article]

Avian reovirus (ARV) strains cause a variety of symptoms in chickens, including viral arthritis/tenosynovitis, a disease that has emerged as a significant cause of economic losses in commercial chicken flocks in recent years in various countries, including Egypt. Furthermore, ARV strains are frequently isolated from birds suffering from malabsorption. In the actual study, seventy-five samples were collected in 2021 and 2022 from broiler and vaccinated broiler breeder flocks at different farms in Giza Province, Egypt, with reovirus-like symptoms such as significant weight fluctuation and arthritis/malabsorption. ARV was screened using real-time PCR, and fifteen positive samples were detected (20%), which were then subjected to embryonated chicken egg (ECE) isolation and molecular characterization (11/15 sample) of a partial segment of the sigma (σ)C gene (S1-gene). Phylogenetically, nine strains were found to belong to genotypic cluster IV, with 82–89% identity with Israeli ARV 2018, and two strains belong to genotypic cluster V with a 78% nucleotide identity with Japan ARV 2021. No correlation between lesions and genotype was found. The strains under study had a low sequence identity (43–55%) when compared with various commercial vaccines belonging to genotypic cluster I (e.g., strain S1133). These findings imply that novel ARV genotypes representing clusters IV and V have recently been introduced to Egyptian poultry farms. A homologous vaccine is suggested; because this variation raises the possibility that commercial vaccines may not offer protection against circulating ARVs. [ABSTRACT FROM AUTHOR]

Orthoreovirus is a nonenveloped double-stranded RNA virus under the Reoviridae family. This group of viruses, especially mammalian orthoreovirus (MRV), are reported with great therapeutic values due to their oncolytic effects. In this review, the life cycle and oncolytic effect of MRV and a few emerging reoviruses were summarized. This article also highlights the challenges and strategies of utilizing MRV and the emerging reoviruses, avian orthoreovirus (ARV) and pteropine orthoreovirus (PRV), as oncolytic viruses (OVs). Besides, the emergence of potential ARV and PRV as OVs were discussed in comparison to MRV. Finally, the risk of reovirus as zoonosis or reverse zoonosis (zooanthroponosis) were debated, and concerns were raised in this article, which warrant continue surveillance of reovirus (MRV, ARV, and PRV) in animals, humans, and the environment. [ABSTRACT FROM AUTHOR]

The year 2023 marks the fiftieth anniversary of the discovery of the bacteriophage φ6. The review provides a look back on the initial discovery and classification of the lipid-containing and segmented double-stranded RNA (dsRNA) genome-containing bacteriophage—the first identified cystovirus. The historical discussion describes, for the most part, the first 10 years of the research employing contemporary mutation techniques, biochemical, and structural analysis to describe the basic outline of the virus replication mechanisms and structure. The physical nature of φ6 was initially controversial as it was the first bacteriophage found that contained segmented dsRNA, resulting in a series of early publications that defined the unusual genomic quality. The technology and methods utilized in the initial research (crude by current standards) meant that the first studies were quite time-consuming, hence the lengthy period covered by this review. Yet when the data were accepted, the relationship to the reoviruses was apparent, launching great interest in cystoviruses, research that continues to this day. [ABSTRACT FROM AUTHOR]

Piscine orthoreovirus genotype 1 (PRV-1) is an endemic virus to the Northeastern Pacific that infects both wild and farmed salmon. To better understand PRV-1 prevalence and transmission pathways in the region, we targeted out-migrating juvenile Pacific Salmon in the Strait of Georgia and Johnstone Strait in British Columbia, Canada, for PRV-1 molecular screening with an emphasis on Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) salmon. A total of 4031 individuals were screened for PRV-1 and we identified an overall virus prevalence of 3.5% from 2011 to 2020. PRV-1 was absent in enhancement facilities and freshwater catchments and predominately found in the marine environment. The detection of PRV-1 varied greatly between species, year and stock of origin, but cumulatively identified that life history and migratory behaviors likely influenced viral prevalence. Specifically, Chinook salmon, which demonstrate long residence time in the Strait of Georgia relative to other species, had the highest PRV-1 prevalence in this study (7.4%). Varying stock composition and regional detection between year classes within the Strait of Georgia further indicated that the sources for Chinook infection were highly variable between years. These findings enhance our understanding for PRV-1 transmission in the region and more generally between/within salmon species. [ABSTRACT FROM AUTHOR]

As the world is experiencing the pandemic of SARS-CoV-2 responsible for COVID-19, one can wonder if members of other family of viruses could possibly emerge. Can such viruses establish a worldwide distribution with consequences similar to SARS-CoV-2? One such threat is the possible emergence of pathogenic reoviruses, especially by zoonotic transmission. Reoviruses are ubiquitous viruses exhibiting a worldwide distribution and various strains or isolates are found in many mammalian species and other vertebrates. When initially discovered, these viruses were named respiratory enteric orphan viruses (hence the acronym "reo") in order to reflect the fact that they could not be clearly associated with any given disease. However, this is not necessarily the case for all of these viruses, as clearly shown for some of these in animals. Significantly, there have been numerous reports of zoonotic transmission, especially from bats to humans. In this manuscript, pertinent properties of reoviruses will be first briefly presented followed by a review of available evidence for zoonotic transmission of pathogenic reoviruses to humans. Future work that appears to be needed for preparedness to the possible emergence of these viruses will then be briefly discussed. [ABSTRACT FROM AUTHOR]

Infecting a wide range of hosts, members of Reovirales (formerly Reoviridae) consist of a genome with different numbers of segmented double stranded RNAs (dsRNA) encapsulated by a proteinaceous shell and carry out genome replication and transcription inside the virion. Several cryo-electron microscopy (cryo-EM) structures of reoviruses with 9, 10 or 11 segmented dsRNA genomes have revealed insights into genome arrangement and transcription. However, the structure and genome arrangement of 12-segmented Reovirales members remain poorly understood. Using cryo-EM, we determined the structure of mud crab reovirus (MCRV), a 12-segmented dsRNA virus that is a putative member of Reovirales in the non-turreted Sedoreoviridae family, to near-atomic resolutions with icosahedral symmetry (3.1 Å) and without imposing icosahedral symmetry (3.4 Å). These structures revealed the organization of the major capsid proteins in two layers: an outer T = 13 layer consisting of VP12 trimers and unique VP11 clamps, and an inner T = 1 layer consisting of VP3 dimers. Additionally, ten RNA dependent RNA polymerases (RdRp) were well resolved just below the VP3 layer but were offset from the 5-fold axes and arranged with D5 symmetry, which has not previously been seen in other members of Reovirales. The N-termini of VP3 were shown to adopt four unique conformations; two of which anchor the RdRps, while the other two conformations are likely involved in genome organization and capsid stability. Taken together, these structures provide a new level of understanding for capsid stabilization and genome organization of segmented dsRNA viruses. Author summary: Mud crab reovirus (MCRV), a putative member of the Sedoreoviridae family in Reovirales, infects an economically important crab, Scylla serrata, and has resulted in serious economic loss for the crab aquaculture. In this study, we report the structure of MCRV, which has allowed us to examine the detailed structural elements that might be responsible for capsid stability, as well as those involved in genome packaging and RdRp organization. The arrangement of viral polymerases inside the capsid differ from what has been seen in other viruses of the same order, as ten of the vertices are occupied by RdRp in a symmetrical organization not seen elsewhere. In addition, the VP11 protein is analogous to the "clamp" protein of turreted reovirads. [ABSTRACT FROM AUTHOR]

The largemouth bass (Micropterus salmoides) is a well-known freshwater fish species that is commonly bred in aquaculture. Unfortunately, this species faces a significant threat from viral diseases, and there is currently no available vaccine to combat them. In this study, we have conducted viral metagenome analysis to explore the RNA virome of largemouth bass, which refers to the collection of all RNA viruses present in the fish. It revealed the existence of 69 known viruses and 117 novel viruses in the liver, spleens, and kidneys of largemouth bass. The diverse range of viruses suggests that their host range may be wider than previously believed. Interestingly, many of the viruses identified in largemouth bass bear similarities to known pathogens found in nonaquatic animals, such as bovine viral diarrhea virus 1 and 2, porcine endogenous retrovirus, feline sarcoma virus, avian sarcoma virus 16, mouse mammary tumor virus, and mammalian orthoreovirus 5. This finding indicates the potential for these viruses to be transmitted across different species to largemouth bass. To confirm the presence of these viruses, reverse PCR and Sanger sequencing were employed to explore the authenticity of the identified RNA viruses. The discovery of this hidden diversity within the RNA virome of juvenile largemouth bass brings attention to the latent viruses that pose a serious threat. Further investigation is crucial to understanding the pathogenicity of these viruses and developing effective measures for disease prevention in largemouth bass aquaculture. • 117 distinct viruses were identified in the liver, spleens, and kidneys of largemouth bass. • Many viruses bear similarities to pathogens found in non-aquatic animals. • Reverse PCR was employed to explore the authenticity of identified RNA viruses. [ABSTRACT FROM AUTHOR]

Sathuperi virus (SATV) and Shamonda virus (SHAV) (family Peribunyaviridae, genus Orthobunyavirus, species Schmallenberg orthobunyavirus) have been suggested to cause congenital abnormalities in ruminants. In this study, we determined the complete genome sequences of SATV KSB-6/C/02 and SHAV KSB-2/C/08 strains, which were obtained from Culicoides biting midges in Japan, by next-generation sequencing and Sanger sequencing. The 3ʹ- and 5ʹ-untranslated region sequences of the M segment of SHAV KSB-2/C/08 strains are distinctly different from those of SATV KSB-6/C/02 and Schmallenberg viruses. This study provides the genome characterization of Japanese strains of SATV and SHAV and presented the genetic variation in the untranslated regions of Schmallenberg orthobunyavirus M segments. [ABSTRACT FROM AUTHOR]