Isolation and identification of pathogenic porcine pseudorabies virus PRV-JF strain

A virulent strain of pseudorabies virus(PRV) was isolated from the brain tissue of an infected piglet and adapted to cell culture through a series of passages and three plaque purifications in PCV1-free PK-15 cells.The isolate(PRV-JF) could induce typical cytopathogenic effect in cells and sustained a markedly increased titre after a series of passages(108.5 TCID50/mL at the 24 th passage).The infectivity of virus could be neutralized with antiserum against PRV in vitro.Immunoperoxidase monolayer assay showed that virus antigens were distributed both in the infected cell nucleolus and cytoplasm.The viral particles have a round or elliptical shape under electron microscope,with a diameter of 110 nm-150 nm(non-enveloped) or 150 nm-180 nm(enve-loped mature viruses).The gE gene of the virus was sequenced and showed a nucleotide homology of 97.7 %-100 % with seven other PRV sequences published in GenBank.Experimental infection in rabbits caused animal death at 24 h-72 h post-inoculation.This study provided a basis for further research on epidemiology,pathogenicity,vaccination and diagnosis of the virus.