Exosomal miRNAs from individual cells are crucial in regulating the immune response to infectious diseases. In this study, we performed small RNA sequencing (small RNA-seq) analysis to identify the expressed and associated exosomal miRNAs in the serum of cattle infected with lumpy skin disease virus (LSDV). Cattle were infected with a 10^6.5 TCID50/mL LSDV Vietnam/HaTinh/CX01 (HT10) strain and exosomal miRNA expression in the serum of infected cattle was analyzed using small RNA sequencing (small RNA-seq). We identified 59 differentially expressed (DE) miRNAs in LSDV-infected cattle compared to uninfected controls, including 18 upregulated and 41 downregulated miRNAs. These 59 miRNAs were used to predict 7656 target genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the target genes were enriched in several biological processes and pathways associated with viral replication, immune response, virus–host interactions, and signal transduction. Additionally, we identified 708 potentially novel cattle miRNAs corresponding to 710 genomic loci. The transcription levels of five miRNA genes (bta-miR-11985, bta-miR-1281, bta-miR-12034, bta-miR-let-7i, and bta-miR-17-5p) were validated using reverse transcription quantitative real-time PCR, showing consistency with the small RNA-seq results. Overall, these findings provide significant insights into the immune and protective responses during LSDV infection in cattle, offering valuable information on identifying new biomarkers and understanding the pathogenesis of LSDV.

This study aimed to evaluate the pathogenic potential of the 2024 Vietnam PRRSV genotype 2 (NA01/2024, isolate). Fifteen 6-week-old piglets were intramuscularly inoculated with 1 × 10^5.5 TCID₅₀/mL of PRRSV, while fifteen control piglets remained uninfected. Blood and nasal swabs were collected every 3 days until 21 days post-infection (dpi). Necropsies were performed on piglets at 6, 15, and 21 dpi. Infected piglets exhibited fever, blue ear, weight loss, respiratory distress, diarrhea, and leucopenia between 3 and 12 dpi. PRRSV was detected in serum and nasal secretions up to 21 dpi, peaking between 6 and 9 dpi. Seroconversion began at 6 dpi, with the highest antibody titers at 21 dpi. Virus load was highest in lung tissues at all intervals, while the spleen and lymph nodes showed higher viral load at later stages. Routine blood tests indicated a slight decrease in red blood cells, hemoglobin, and reticulocytes, along with a notable increase in monocytes in infected piglets. Cytokine levels (IFN-γ, IL-6, and IL-10) in serum and lung tissues were significantly higher in infected piglets compared to controls. Additionally, the PRRSV infection triggered innate immune responses, including cytokines, growth factors, and chemokines in whole blood and tissues such as IFN-α, IFN-β, TNF-α, IL-1β, etc. These findings highlight the pathogenicity of the Vietnam PRRSV NA01/2024 isolate and its impact on the immune response, providing insights into PRRSV infection mechanisms and strategies for prevention and control.