Abstract：The purpose of this study was to investigate the infection of Borna disease virus (BDV) in viral encephalitis (VE) patients and the animals they exposed to, and to probe BDV infection mechanisms in Ningxia region. BDV nucleic acid and the amino acid sequences were analyzed after transformation, phylogenetic origin of the virus was constructed as well. The P24 and P40 fragments of BDV were detected by nested reverse transcriptase polymerase chain reaction (RT-PCR) with real time PCR in peripheral blood mononuclear cells (PBMCs) from VE patients and the exposed animals. Before comparing with the overseas strains including HE80, H1766 and strain V by MEGA and DnaSP4.0, the positive samples were cloned and sequenced to construct the phylogenetic tree. A total of 3 examples of BDV were detected to be positive in 60 VE patients. The positive rates of BDV for cattle sheep were 1.27%(9/710). The gene cluster analysis showed that the nucleotide sequence and deduced amino acid sequence of human and animal BDV were 100% homologous with the horse-derived strain HE80 in Germany. The reconstruction of the gene phylogenetic tree showed that the BDV nucleotide sequences of VE patients and animals in Ningxia have form Ningxia-Germany-Japan hybrid branch with oversea standard strains. At the same time, the BDV sequences of sheep in Ningxia have also form an independent branch. There was a natural infection of BDV among human and animal in Ningxia Province and the infection source was probably originated from animals. Respiratory tract was likely to be the main channel of infection and may cause non-specific clinical symptoms such as encephalitis. The gene sequence was highly homologous with HE80 detected from ill horses in Germany. Results indicated that the virus might be introduced from abroad and have experienced gene mutation. There was also a possibility in cross-infection among human, and sheep.
