Molecular Biological Characteristics of Bovine Gamma Herpesvirus 4 Originated from Different Clinical Sources

Bovine herpesvirus 4 (BoHV 4) is a member of the Herpesviridae family in the Gammaherpesvirinae subfamily, Radinovirus genus. The purpose of this study was to isolate BoHV 4 from calves, heifers and cows presenting various clinical entities – respiratory, conjunctivitis, pneumonia, skin damage, genital lesions and abortion, and to characterize its molecular biological features. Primary and permanent bovine cell cultures were used for virus isolation and culturing. Polymerase chain reaction (PCR) was used to confirm the gB and TK genes and the PCR products were sequenced. After infecting the primary bovine and permanent cell lines, a cytopathic effect typical of BoHV 4 was observed and 10 cytopathic viral agents were isolated. Amplification products with molecular weights of 567 and 615 bp for the Tk and gB genes, respectively, were found after PCR. After the BoHV 4 isolates had been sequenced, 473 and 476 nucleotide sequences were analyzed for the Tk and gB genes, respectively. The phylogenetic trees constructed based on the Tk and gB genes of Bulgarian BoHV 4 strains fall within the same branch with the reference BoHV 4 European strains deposited in the genomic bank and their genomic features were similar to European sequenced genomes of other Radinoviruses.