Monitoring of genetic alterations of lumpy skin disease virus in cattle after vaccination in Thailand

Lumpy skin disease (LSD) is a contagious viral disease that has a significant impact on the cattle and buffalo agricultural industries. The use of live attenuated LSDV vaccines (LAVs) is the most efficient method of disease prevention. However, it is well recognized that LAVs might result in viral mutation that could enhance viral infectivity or virulence. The goal of this research was to monitor the changes in genetic characteristics of the lumpy skin disease virus (LSDV) in cattle after vaccination in Thailand. Five LSDV DNA samples from five different regions of Thailand including North, Northeast, West, Central, and South were selected. All samples came from non-vaccinated animals that developed LSD clinical signs after vaccination with the LAVs in each area. The samples were examined using real-time PCR targeting the p32 gene and the whole genome sequences were analyzed. The genomes were compared to LSDV/Thailand/Yasothon/2021, a recombinant LSDV strain discovered during the early stage of the outbreak in Northeast Thailand. Single nucleotide polymorphisms (SNPs), amino acid changes, and affected proteins were analyzed. The study discovered that following immunization in the area, LSDVs from Chiang Mai (North), Khon Kaen (Northeast), and Nakhon Pathom (Central) differed from the Yasothon isolate. Open reading frame (ORF) 032 Poly (A) polymerase large subunit, ORF094 virion core protein, and ORF133 DNA ligase-like protein, as well as virulence and host range genes; ORF144 Kelch-like protein and ORF148 Ankyrin-like protein had mutations, while the genomic sequences of Prachuap Khiri Khan (West) and Trang (South) isolates are 100% identical to the Yasothon virus. Mutations occurred in LSDV genomes from the North, Northeast, and Central regions following immunization. As a result, viral genetics should be examined on an annual basis for effective diagnosis and control of the disease.