Phylogenetic analysis of glycoprotein B gene sequences of bovine herpesvirus 1 isolates from India reveals the predominance of subtype 1.1.

Aim: This study was conducted for the isolation and molecular characterization of bovine herpesvirus 1 (BoHV-1) isolated from the nasal and vaginal swabs collected from naturally infected cattle showing clinical symptoms of the respiratory disease. Materials and Methods: Isolation of BoHV-1 virus performed on clinical samples collected from 65 cattle from five states of India. The BoHV-1 isolates were further confirmed by polymerase chain reaction (PCR) using primers specific for glycoprotein B (gB) genomic region. PCR amplification was performed using previously published gB gene-specific primer pairs. gB PCR amplicons obtained from all isolates were sequenced, and phylogenetic analysis was performed using software. Results: A total of 12 samples were found positive in cell culture isolation. 11 isolates showed the visible cytopathic effect on Madin-Darby bovine kidney after 72 h. Partial sequence analysis of gB gene of all isolates revealed 99.0-100% homology between them. All isolates showed 99.2-99.8% homology with Cooper stain. Conclusion: BoHV-1.1 is the predominant circulating subtype of BoHV in India, and all isolates have homology with Cooper stain.