Genetic diversity and isolation of Lumpy skin disease virus in Andhra Pradesh, India

Objectives: In the present investigation, the molecular epidemiology of the lumpy skin disease virus circulating in Andhra Pradesh, India, was studied. Materials and Methods: A total of 31 samples were collected from outbreak areas of Andhra Pradesh from September to December 2022. The presence of LSDV was detected by PCR using primers targeting the Capripoxvirus (CaPV)-specific P32 gene and the LSDV-specific RPO30 gene. Positive samples were further used for isolation of the virus by employing MDBK cell lines. The molecular epidemiology of LSDV isolated in the present study was analyzed by phylogeny. Results: Of the 31 samples, 26 were found positive for LSDV by PCR employing primers targeting the CaPV-specific P32 gene and the LSDV-specific RPO30 gene. Clinical samples (n = 10) confirmed positive by PCR were further processed for isolation of LSDV in MDBK cell lines. The virus could be isolated from two samples during the fifth passage. Phylogenetic analysis of the LSDV isolate based on the full-length ORF036 gene (RPO30) showed 100% identity and formed a distinct clade with isolates of Middle East Asia and Africa. Amino acid-specific signatures to differentiate CaPVs were noticed, and estimates of evolutionary divergence over sequence pairs between clusters were determined that showed a distance of 9.52% between vaccine strains and the field isolates. Conclusion: Genetic characterization of the LSDV isolate showed key substitutions within the spe¬cific amino acid signatures of the RPO30 gene, which may be implicated in the increased virulence of LSDV isolates during the present outbreak.