Search Results (193)

Avian reovirus (ARV) is a ubiquitous pathogen in commercial poultry, traditionally associated with viral arthritis, malabsorption syndrome, and growth retardation. In recent years, the rapid genetic diversification of ARV has raised increasing concerns regarding vaccine mismatch, immune dysregulation, and complex disease outcomes in vaccinated flocks. In this study, an integrated investigation combining large-scale field surveillance, molecular characterization, and controlled animal experiments was conducted to elucidate the epidemiological features of ARV and its impact on heterologous vaccine-induced protection. Epidemiological surveillance revealed widespread ARV circulation in commercial poultry flocks, with marked genetic divergence between contemporary field isolates and classical vaccine strains. Phylogenetic analysis based on the σC gene demonstrated that the majority of circulating strains clustered within emerging genotypes that were genetically distinct from vaccine-related lineages. Using a controlled infection–vaccination–challenge model, prior ARV infection was shown to significantly impair humoral immune responses induced by an inactivated Aviadenovirus hydropericardii (fowl adenovirus serotype 4, FAdV-4) vaccine, as evidenced by reduced FAdV-4-specific antibody levels. Importantly, ARV pre-infection compromised vaccine-mediated protection and was associated with enhanced FAdV-4 pathogenicity following challenge, resulting in increased mortality, aggravated clinical manifestations, and more pronounced pathological lesions. These findings indicate that prior ARV infection is associated with reduced FAdV-4 vaccine-induced humoral responses and partial loss of protective efficacy under controlled experimental conditions. Importantly, this study provides quantitative experimental evidence using a defined infection–vaccination–challenge interference model rather than proposing a previously unrecognized virus-virus interaction. These results underscore the necessity of enhanced ARV surveillance and optimized immunization strategies in modern poultry production systems. Full article

Avian reovirus (ARV) is a major poultry pathogen recently recognized for its potential as an oncolytic virus that selectively infects and kills cancer cells without harming healthy human cells. However, the receptors mediating ARV entry into cancer cells remain unclear. Using mouse melanoma B16-F10 cells as a model, this study identified ARV-binding receptor candidates through viral overlay protein binding assay (VOPBA), SDS-PAGE, and LC-MS/MS analysis. Plaque-forming assays (PFAs) evaluated viral replication efficiency, while co-immunoprecipitation (Co-IP) and proximity ligation assay (PLA) confirmed direct interactions between viral σC and host receptor proteins. Functional assays using shRNA knockdown and antibody blocking demonstrated that inhibition of Plg-RKT expression markedly reduced ARV infection. Western blot analysis revealed that ARV binding to Plg-RKT activates Src and p38 MAPK signaling pathways, which promote caveolin-1 phosphorylation and caveolae-mediated endocytosis. These findings identify Plg-RKT as a crucial receptor mediating ARV σC binding and entry into B16-F10 melanoma cells. Furthermore, activation of Src-p38 MAPK signaling was shown to be essential for viral internalization. This study elucidates the molecular mechanism underlying ARV entry into melanoma cells and provides valuable insight for improving the selectivity and therapeutic potential of ARV as an oncolytic virus. Full article

Transmissible viral proventriculitis (TVP) is an emerging disease in chickens, linked to chicken proventricular necrosis virus (CPNV), a recently identified birnavirus. Here, we provide the first molecular confirmation of TVP in Bangladesh from a coloured meat-type parent stock (PS) flock, while documenting a contemporaneous white layer flock with consistent clinical signs and characteristic gross lesions. Affected birds exhibited growth retardation, diarrhoea, and increased mortality, alongside hallmark gross changes in proventricular enlargement and wall thickening. From the meat-type PS, proventricular samples were collected for histopathology and molecular diagnostics. Histological analysis revealed severe glandular epithelial damage, necrosis, mononuclear infiltration, epithelial hyperplasia, and metaplasia. Using RT-PCR on nucleic acid extracted from FTA card samples, CPNV was detected. In addition, infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), and avian reovirus (ARV) nucleic acids were also identified. The amplified CPNV VP1 fragment was sequenced, and phylogenetic analysis placed the Bangladeshi strain within clades of previously reported CPNV isolates. This study represents the first molecularly confirmed report of CPNV associated with TVP in Bangladesh, highlighting the need for active surveillance in commercial and breeder poultry flocks to understand the virus’s epidemiology and support the development of control strategies. Full article

This study aimed to establish an indirect ELISA for detecting the avian reovirus (ARV) epidemic strain xj-1.1 by using the purified recombinant protein pET-σC as the coating antigen. To optimize assay performance, key parameters were systematically evaluated, including antigen-coating concentration, serum dilution, blocking reagent and duration, serum incubation time, and the dilution and reaction time of the HRP-conjugated secondary antibody. The optimized conditions identified were a coating antigen dilution of 1:100, serum dilution of 1:1600, coating at 37 °C for 1 h followed by overnight incubation at 4 °C, and blocking with 5% skim milk for 2 h. The optimal serum incubation time was 1.5 h, with the secondary antibody diluted 1:1000 and incubated for 2 h, followed by a 20-min color development step. The cut-off value for distinguishing positive and negative samples was determined to be 0.121. Validation of the assay demonstrated favorable specificity, sensitivity, and repeatability, indicating that the developed indirect ELISA provides a reliable method for detecting ARV xj-1.1 infection. Full article

The use of experimental animals with unified quality standards is an important condition for ensuring the effectiveness of scientific research. Ectromelia virus (ECTV), murine hepatitis virus (MHV), reovirus type 3 (Reo-3), and murine parvoviruses (MUV) are the four pathogens that need to be eliminated from SPF (Specific Pathogen-Free) level mice. These four pathogens present fast transmission and high pathogenicity, making it difficult to control. The previously described detection methods present substantial limitations in efficiency and accuracy. Thus, there is an urgent need for rapid and precise diagnostic methods to improve prevention and diagnosis efforts. In this study, we developed a one-step multiplex real-time PCR (mrt-PCR) detection method that can simultaneously detect four key viral pathogens causing diseases in laboratory mice without cross-reactivity with other mouse susceptible pathogens. We tested 128 suspected diseased mouse tissue samples collected from Beijing, and the results showed that this new method has higher sensitivity and specificity than ordinary PCR. The detection limit for ECTV, MHV, and MUV was determined to be 1.08 × 10¹ copies/μL, 1.14 × 10¹ copies/μL, 2.38 ×10¹ copies/μL, and 1.08 × 10¹ copies/μL, respectively. In addition, the assay showed excellent reproducibility, with a coefficient of variation below 1.5%, strong linear correlation (R² > 0.996), and amplification efficiency between 90% and 100%. In summary, the mrt-PCR serves not only as a rapid and accurate detection and early prevention method for laboratory mice but also constitutes a robust tool for microbial quality control in laboratory mice. Full article

Infectious bursal disease virus (IBDV) and avian reovirus (ARV) are major immunosuppressive pathogens controlled through the widespread use of live attenuated vaccines. Concerns persist regarding potential immune interference when these vaccines are co-administered, though comprehensive in vivo data are lacking. Here, we reported the immunogenicity and protective efficacy of a live IBDV vaccine (W2512G-61) and a live ARV vaccine (ZJS) administered simultaneously or sequentially at 3-, 5-, and 7-day intervals in specific-pathogen-free (SPF) chickens. The IBDV live vaccine elicits strong, interval-independent humoral immunity and conferred 100% protection, demonstrating no compromise from ARV co-administration. Conversely, ARV-specific immunity was severely impaired by close temporal vaccination. ARV protection rates fell from 86.7% (ARV-only) to 46.7% with simultaneous administration and from 93.3% to 66.7% with a 3-day interval. Extending the interval to five or seven days eliminated this interference, restoring ARV antibody titers and protection to levels equivalent to ARV-only control vaccinated groups. This study provides the first definitive evidence of asymmetric immune interference between live IBDV and ARV vaccines. The results establish a minimum safe interval of five days to prevent interference and ensure robust ARV vaccine efficacy. These findings offer critical, evidence-based guidance for optimizing vaccination schedules to improve disease control in commercial poultry production. Full article

Avian reovirus (ARV) infections pose a significant and evolving threat to China’s poultry industry, the world’s largest. Diverse farming systems—ranging from modern intensive operations to traditional waterfowl-poultry polyculture—foster a unique ecological niche for ARV, defined by complex serotypic and genotypic diversity, marked regional variations, potential interspecies transmission between chickens and waterfowl, and recurrent co-infections. Collectively, these factors undermine the efficacy of conventional diagnostic approaches. This review systematically outlines the current epidemic landscape of ARV in China, highlighting the molecular characteristics of prevailing strains (particularly those from waterfowl) and their roles in diagnostic evasion. We critically assess the performance and limitations of existing diagnostic techniques (virus isolation, ELISA, PCR/qPCR) within the Chinese epidemiological setting. Furthermore, we discuss innovative technologies—including multiplex qPCR, CRISPR-Cas systems, and next-generation sequencing (NGS)—that offer potential for developing next-generation diagnostics tailored to China’s specific challenges. Finally, we propose future directions, with an emphasis on standardization, data sharing, and interdisciplinary collaboration to bridge the gap between cutting-edge innovation and on-farm application for precise ARV control. Full article

Novel duck reovirus encodes a new nucleus-localized protein, p18. We aimed to investigate whether the nuclear entry of p18 is dependent on viral replication, identify the cellular proteins that interact with p18, and determine the transporters involved in the nuclear import. The subcellular localization of p18 was observed by confocal microscopy. Cellular proteins interacting with p18 were identified through data-independent acquisition qualitative proteomics. The interaction between p18 and importin α was determined by confocal microscopy, co-immunoprecipitation (Co-IP) and molecular docking. We observed that p18 was localized to the nucleus in transfected cells. Importin α1, α3, α4, α5, and α7 were colocalized and co-immunoprecipitated with p18. The importin α/β1 pathway inhibitor reduced the nuclear distribution of p18. The truncated form of p18, lacking the C-terminal region, was predominantly distributed in the cytoplasm. Collectively, our research suggests that the nuclear entry of p18 is independent of viral infection, importin α is implicated in the nuclear import of p18, and the C-terminal region of p18 is crucial for nuclear localization. Full article

High-grade gliomas—particularly glioblastoma (GBM)—remain refractory to standard-of-care surgery followed by chemoradiation, with a median overall survival of ~15 months. Oncolytic viruses (OVs), which selectively infect and lyse tumor cells while engaging antitumor immunity, offer a mechanistically distinct therapeutic modality. This review synthesizes clinical progress of OVs in GBM, with emphasis on oncolytic herpes simplex virus (oHSV) and coverage of other vectors (adenovirus, reovirus, Newcastle disease virus, vaccinia virus) across phase I–III trials, focusing on efficacy and safety. Key observations include the encouraging clinical trajectory of oHSV exemplars—T-VEC (approved for melanoma) and G47Δ (approved in Japan for recurrent GBM)—the multi-center exploration of the adenovirus DNX-2401 combined with programmed death-1 (PD-1) blockade, and the early-stage status of reovirus (pelareorep) and Newcastle disease virus programs. Emerging evidence indicates that oHSV therapy augments immune infiltration within the tumor microenvironment and alleviates immunosuppression, with synergy when combined with chemotherapy or immune checkpoint inhibitors. Persistent challenges include GBM’s inherently immunosuppressive milieu, limitations imposed by the blood–brain barrier, intrapatient viral delivery and biodistribution, and concerns about viral shedding. Future directions encompass programmable vector design, optimization of systemic delivery, biomarker-guided patient selection, and rational combination immunotherapy. Collectively, OVs represent a promising immunotherapeutic strategy in GBM; further gains will hinge on vector engineering and precision combinations to translate mechanistic promise into durable clinical benefit. Full article

Muscovy duck reovirus (MDRV) and novel duck reovirus (NDRV) are major pathogens in duck breeding, leading to substantial economic losses in the waterfowl industry. This study aimed to develop a precise detection and differentiation method for both viruses simultaneously. Specific primers and probes targeting the S3 gene were designed, and a duplex TaqMan-based real-time RT-PCR assay was established following optimization of reaction conditions. The assay demonstrated high amplification efficiency (100.1–106.7%), strong linear correlation (R² > 0.999), and low limits of detection (13–25 copies/µL). Intra- and inter-assay coefficients of variation were below 1.5%, confirming excellent repeatability and stability. Applied to 122 clinical duck tissue samples, the assay detected MDRV in 29.5% (36/122) and NDRV in 39.3% (48/122) of samples, with results fully validated by singleplex RT-PCR assays. Our study provides a reliable, specific, and reproducible tool for surveillance and epidemiological studies of MDRV and NDRV. Full article

Avian reovirus (ARV) is an important pathogen of poultry, yet the molecular responses to ARV across cell types remain unknown. The present study explores the differential transcriptomic responses to ARV S1133 infection in three cell types, i.e., chicken embryo kidney (CEK), chicken embryo liver (CELi), and macrophage-derived cells (HD11) at 6, 12, and 24 h post-inoculation (hpi). CELi cells exhibited the highest viral replication rates at all timepoints, with maximal titer observed at 24 hpi, whereas HD11 cells showed limited viral replication but extensive host transcriptional activity. Differential gene expression analysis revealed that macrophage-derived (HD11) cells, despite the lower viral load, presented the most pronounced transcriptional changes. CEK cells demonstrated a unique activation of immune-related pathways, specifically those related to lymphocyte chemotaxis and type II interferon response. CELi cells showed upregulation of expression of genes involved in defense against viruses. Protein–protein interaction (PPI) analysis identified key antiviral genes, including IFI6, OASL, RSAD2, SAMD9L, and MX1, as central nodes. In CELi, significant alternative splicing events were observed in transcripts of several genes, including those implicated in immunity. Taken together, results indicate that inoculation of ARV triggered cell-type and time-dependent viral replication and stimulated transcriptional activity linked with unique but functionally interconnected pathways. Full article

Background: Mammalian orthoreovirus is a ubiquitous double-stranded RNA virus that causes mild respiratory and enteric infections, primarily in infants and young children. Its significant environmental stability and association with conditions like celiac disease highlight an unmet medical need, as no licensed vaccine or antiviral treatment currently exist. Methods: An immunoinformatics-driven approach was employed to design a multi-epitope vaccine. The highly antigenic inner capsid protein Sigma-2 was used to predict cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and linear B cell epitopes using NetCTL, NetMHCpan, NetMHCIIpan, and IEDB tools. Selected epitopes were fused with appropriate linkers. The construct’s antigenicity, allergenicity, and physicochemical properties were evaluated. The tertiary structure was predicted with AlphaFold2, refined, and validated. Molecular docking with TLR2 and TLR4 was performed using HDOCK, and immune response simulation was conducted with C-ImmSim. Finally, the sequence was codon-optimized for E. coli expression using JCat. Results: The final vaccine construct comprises one CTL, four HTLs, and one B cell epitope. It is antigenic (VaxiJen score: 0.5026), non-allergenic, and non-toxic and possesses favorable physicochemical properties, including stability (instability index: 32.28). Molecular docking revealed exceptionally strong binding to key immune receptors, particularly TLR2 (docking score: −324.37 kcal/mol). Immune simulations predicted robust antibody production (elevated IgM, IgG1, and IgG2) and lasting memory cell formation. Codon optimization yielded an ideal CAI value of 0.952 and a GC content of 57.15%, confirming high potential for recombinant expression. Conclusions: This study presents a novel multi-epitope vaccine candidate against reovirus, designed to elicit broad cellular and humoral immunity. Comprehensive in silico analyses confirm its structural stability, potent interaction with innate immune receptors, and high potential for expression. These findings provide a strong rationale for further wet-lab studies to validate its efficacy and advance it as a promising prophylactic candidate. Full article

Glioblastoma (GBM) is an aggressive and common form of central nervous system primary malignant tumor in adults. GBM accounts for about half of all gliomas. Despite maximal resection, radiotherapy, and temozolomide, median survival is still 12–15 months because of tumor heterogeneity, diffuse infiltration, and therapeutic resistance. Recurrence is nearly universal, underscoring the need for novel therapies. Oncolytic virotherapy demonstrates a promising strategy that combines direct tumor cell lysis with immune activation. Tumor-selective viruses replicate within malignant cells, induce cell death, and release tumor antigens, thereby reshaping the immunosuppressive microenvironment. Several viral backbones have advanced to clinical testing, including adenovirus (DNX-2401), herpes simplex virus (G47Δ, G207), poliovirus (PVS-RIPO), measles virus (MV-CEA), reovirus (pelareorep), vaccinia virus (Pexa-Vec), and vesicular stomatitis virus (VSV-GP). The approval of G47Δ in Japan for malignant glioma marks a milestone, with early trials demonstrating safety and signals of durable benefit, particularly in combination regimens. Current research emphasizes engineering viral genomes to enhance selectivity, immune stimulation, and resistance to clearance, while exploring synergistic combinations with radiotherapy, chemotherapy, immune checkpoint inhibitors, and tumor-treating fields. Advances in delivery, such as convection-enhanced infusion and blood–brain barrier modulation, are also under investigation. Despite obstacles, oncolytic virotherapy holds significant potential within multimodal GBM strategies. Full article

Avian viral arthritis (AVA), caused by avian reovirus (ARV), is a viral disease in chickens that has led to significant economic losses in the poultry industry. Recent studies have shown that traditional ARV vaccines based on the S1133 strain fail to protect against emerging ARV variants. In this study, we isolated and characterized three ARV strains (G4, YV, WF) from immunized chicken flocks with respiratory and arthritic symptoms. Genomic analysis revealed that the σC genes of G4, YV, and WF shared only 55.5%, 55.7%, and 58.7% sequence homology, respectively, with the S1133 strain. Phylogenetic analysis placed them in different branches, indicating they are variant strains. YV and WF belong to genotype III, and G4 falls into genotype VI. Whole genome analysis revealed gene segment reassortment among the variants. Pathogenicity testing in three-week-old SPF chickens showed that G4 (genotype VI) caused swelling of footpads, whereas WF (genotype III) did not. G4-infected chickens exhibited significantly higher viral loads in the thymus, lungs, spleen, and bursa of Fabricius than those in the WF-infected chickens, indicating viruses from different genotypes showed various pathogenesis. These results suggested an urgent need for new updates of vaccines against the variant ARVs, especially the genotype VI virus. Full article

Infections caused by avian orthoreovirus represent an emerging problem with a major impact on the global poultry industry, especially in the intensive rearing of broilers. This article addresses, in a complex manner, the etiology of some clinical syndromes of interest in poultry farming: malabsorption syndrome and arthritis/tenosynovitis syndrome. Data are presented, starting from the development and physiology of the digestive tract in broiler chickens in the post-hatch period, epidemiological data, clinical signs, morphopathological changes in the intestine, and diagnostic methods in orthoreovirus infections. The development of the digestive tract is influenced by factors such as diet, digestive enzymes, intestinal pH, and intestinal microbiome/virome. Avian orthoreoviruses, belonging to the Reoviridae family, are double-stranded RNA viruses with multiple tropism. Phylogenetic analysis revealed the existence of at least six major genotypes, with a heterogeneous geographical distribution and genetic diversity that complicates control measures with vaccination. Characterization of the intestinal virome of broilers highlights many other enteric viruses, in addition to reoviruses, with pathogenic potential in triggering malabsorption syndrome. Thus, we can state that the etiology of malabsorption syndrome is not unitary, with the association of several viruses with intestinal tropism aggravating the clinical signs. The article describes viral identification methods, including classical techniques and advanced next-generation sequencing (NGS) approaches, used to characterize the intestinal virome and emerging pathogens. Finally, for prophylaxis, autogenous vaccines adapted to local circulating strains are recommended. Frequent genetic recombinations and high antigenic variation require continuous monitoring and constant adaptation of immunization schedules to control the disease. Full article