Genetic and Pathogenic Characterization of a Lumpy Skin Virus Disease Strain from a Diseased Cattle in Northern Vietnam

Lumpy skin disease (LSD) is a highly contagious transboundary viral disease that causes substantial economic losses to the global cattle industry, including Vietnam.This study was conducted to diagnose, analyze the genome sequence, and evaluate the pathogenicity of the Lumpy skin disease virus (LSDV) strain responsible for lumpy skin disease (LSD) outbreaks in Vietnam in 2021.Real-time PCR and next-generation sequencing (NGS) techniques were employed to detect LSDV in clinical samples and to sequence the viral genome.LSDV DNA was successfully detected in clinical specimens using real-time PCR.The complete genome sequence of the LSDV/Vietnam/21L10 strain, comprising 146,083bp and 149 open reading frames (ORFs), was successfully obtained.Comparative genomic analysis revealed a high level of nucleotide similarity between the LSDV/Vietnam/21L10 strain and other virus strains circulating in Vietnam (99.99%) and China (99.99%).Phylogenetic analysis further demonstrated that the LSDV strain identified in this study belongs to the same genetic clade as strains circulating in Vietnam and China, and is distinct from vaccine strains.Experimental infection of cattle (n=3) with LSDV/Vietnam/21L10 resulted in typical clinical manifestations, including fever, depression, anorexia, lacrimation, the development of cutaneous nodules that ruptured and left scars, and regional lymphadenitis, whereas mock-infected cattle (n=3) were clinically healthy.These findings confirm that the LSDV/Vietnam/21L10 strain is a virulent field isolate.