Bluetongue virus (BTV) infection induces profound and intricate changes in the transcriptional profile of the host to facilitate its survival and replication. However, there have been no whole-transcriptome studies on ovine lung microvascular endothelial cells (OLMECs) infected with BTV. In this study, we comprehensively analysed the whole-transcriptome sequences of BTV-1 serotype-infected and mock-infected OLMECs and subsequently performed bioinformatics differential analysis. Our analysis revealed 1215 differentially expressed mRNA transcripts, 82 differentially expressed long noncoding RNAs (lncRNAs) transcripts, 63 differentially expressed microRNAs (miRNAs) transcripts, and 42 differentially expressed circular RNAs (circRNAs) transcripts. Annotation from Gene Ontology, enrichment from the Kyoto Encyclopedia of Genes and Genomes, and construction of endogenous competing RNA network analysis revealed that the differentially expressed RNAs primarily participated in viral sensing and signal transduction pathways, antiviral and immune responses, inflammation, and extracellular matrix (ECM)-related pathways. Furthermore, protein‒protein interaction network analysis revealed that BTV may regulate the conformation of ECM receptor proteins and change their biological activity through a series of complex mechanisms. Finally, on the basis of real-time fluorescence quantitative polymerase chain reaction results, the expression trends of the differentially expressed RNA were consistent with the whole-transcriptome sequencing data, such as downregulation of the expression of COL4A1, ITGA8, ITGB5, and TNC and upregulation of the expression of CXCL10, RNASEL, IRF3, IRF7, and IFIHI. This study provides a novel perspective for further investigations of the mechanism of the ECM in the BTV-host interactome and the pathogenesis of lung microvascular endothelial cells.

Bluetongue virus (BTV) infects various ruminant species, posing significant threats to animal health and causing substantial economic losses to the livestock industry. Ovine type II alveolar epithelial cells (OAECIIs) play crucial roles in maintaining pulmonary structural integrity and modulating immune responses. Their dysfunction is closely associated with lung disease pathogenesis, making them important therapeutic targets. However, OAECIIs’ immunoregulatory functions and early response mechanisms during BTV infection remain unclear. To address this, we analyzed transcriptomic changes in OAECIIs following BTV-1 infection. RNA-seq revealed 1047 and 852 differentially expressed genes (DEGs) at 8 and 12 h post-infection (hpi), respectively, compared to uninfected controls. Bioinformatics analysis showed significant upregulation of nucleic acid-sensing receptors, interferon-stimulating factors, inflammatory mediators, and cytokines during early infection, mediated primarily through type I interferon signaling, TNF signaling, and cytosolic DNA-sensing pathways. We identified MAD5, ZNFX1, cGAS, OAS, PKR and ZBP1 as key pattern recognition receptors in OAECIIs during BTV infection. The IFN-β, MX1/2, RSAD2 and PLSCR1 pathways mediated antiviral responses, while IL-15, CXCL10, CCL2 triggered inflammatory responses, collectively causing structural alterations through AQP1/9 and tight junction protein modulation. These findings provide critical insights into early antiviral mechanisms and cellular structural changes in OAECIIs during BTV infection, establishing a foundation for understanding pneumonia pathogenesis and developing targeted BTV therapies.

Bluetongue virus belongs to the Reoviridae family, which causes morbidity in ruminants. Herein, we report the full-length genome sequence of a recombinant BTV strain of serotype 1 (YNDH/103/2013) isolated from sentinel cattle in Yunnan Province, China, in 2013. To identify and understand the characteristics of YNDH/103/2013, we screened closely related viruses using Simplot 3.5.1 software and conducted verification via phylogenetic analysis using MEGA 11.0.13 software. Phylogenetic analysis and segment examination showed that the YNDH/103/2013 strain likely originated from multiple recombination events involving prevalent strains such as Y863, NRT37/ABT/HSR, and YTS-4 in China and India. The genome of BTV-1/YNDH/103/2013 derives from at least three reassortments with these strains, showing recombination breakpoints mainly in segments 4, 6, 8, and 9. This study improves our understanding of the origin and spread of BTV-1 in China.

Bluetongue (BT) is an infectious disease affecting domestic and wild ruminants caused by the Bluetongue virus (BTV). The development of safe and broad-spectrum vaccines represents the most effective approach for disease control. This review comprehensively elaborates recent advances in BTV research, including etiological characteristics, antigenic epitopes and immunity, inactivated vaccines (IVs), live attenuated vaccines (LAVs), virus-like particle vaccines (VLPs), viral vectored vaccines, subunit vaccines, disabled infectious single cycle (DISC) vaccines, and disabled infectious single animal (DISA) vaccines, providing valuable references for further investigations on BTV antigenic epitopes and vaccine development. Despite this progress, several critical limitations remain. Many next-generation vaccines improve safety and DIVA compatibility at the cost of reduced immunogenicity, and most novel platforms are evaluated mainly in mouse models with few field trials in natural target species. Moreover, owing to the serotype-specific nature of BTV, most vaccines still fail to provide broad-spectrum immunity. Future efforts should therefore prioritize target-species validation, conserved T-cell antigens such as NS1/NS2, and multivalent or chimeric vaccine design.