Abstract: A strain of Japanese encephalitis virus （JEV） was isolated from the brain of aborted fetus of a JEV infected pregnant sow in Jiangsu Province. The biological characteristics of this isolate were identified. The JEV positive sample was inoculated and passaged on BHK\|21 cells， and inoculated intracranial on mice. The isolate was identified by RT\|PCR， CPE， and confirmed by immunofluorescence assay （IFA）.The TCID50 of this isolate was measured using BHK\|21 cells. The results indicated that the JEV strain was successfully isolated. It could induce cytopathogenic effect （CPE） on BHK\|21 cells， and specific fluorescence could be observed. The TCID50 of this strain was 1070.The E proteins amino acid sequence was compared with those of different genotype of JEV strains available in GenBank. A phylogenetic tree was constructed based on E gene sequences of the isolate and some other JEV strains. The isolate belonged to JEV genotype Ⅲ. The pathogenicity to the mice demonstrated that the isolate was highly neuroinvasiveness. This study provided a basis for further research on epidemiology and vaccine of the virus.

Key words: Japanese encephalitis virus, isolation and identification, biological characteristics