Identification and Phylogenetic Analysis of an Orf Virus Isolated from an Outbreak in Boer Goat in Shanxi Province

Abstract To identify and analyze the Orf virus in Shanxi Province, China, an Orf virus strain was successfully isolated from crust materials of boer goat with clinical sore mouth symptom from a goat farm of Shanxi Province by passaging in lamb testis (LT). The Orf virus was identified by enzyme linked immunosorbent assay (ELISA) test, recurrent infection test, transmission electron microscopy, and PCR. The nucleotide and amino acid sequences of two genes of the Orf virus were analyzed. The results showed that under the electron microscopy the virus had a presence of typical parapoxvirus virions and there were many eosinophilic intracytoplasmic inclusions observed by hematoxylin-eosin (H&E) stain. In ELISA test, optical density (OD) readings of the sample showed a positive result, and the rabbits infected with the virus showed a typically Orf virus-infected appearance. All these findings proved that the sample was an Orf virus. The phylogenetic studies of Orf B2L and Orf F1L genes showed that the virus clustered in different branches and were closer to the Orf virus Nantou (DQ904351) and the OV-SA00 isolates (AY386264). Furthermore, the above results may provide some insight into the genotype of the etiological agent responsible for the Orf outbreak in Shanxi Province, and could also provide a comparative view of the B2L and F1L genes of parapoxvirus.