Isolation, Identification And Biological Characterization Of Japanese Encephalitis Virus Sichuan Strain

Japanese encephalitis virus(JEV), being a member of the family Faviviridae, usually infected the human body through mosquitoes and then might cause acute viral encephalitic and neurologic disease. This study provided information for the epidemiology and taxology of JEV, and was useful for providing technological means and academic basis to effectively prevent.. The research content was as follows.1. Isolation and identification of Japanese encephalitis virus30 sceptical samples of JEV collected from Sichuan Province were treated with the general methods.These samples were cultured in BHK21 cell, as a result, two of them caused CPE. As the passage times increased, CPE became more regular.3-5 days old neonatal rat was infected by intracerebral inoculation. Spreading 3 generations after inoculation 72 h, rat began to be depressed, poor feeding, seizures, fever, weight loss. Until 96-120 h, most of suckling mice appeared tremor, rigidity, and then died. After autopsy, we found that the brain is obviously congestive and oedematous.Two sceptical strains of JEV were identified by use of the method of the transmission electron microscopy, IFA, ELISA, neutralization test and PCR detection. The result indicated:The globular virion could be seen in cytoplasm with 60nm size by electronmicroscope; The serum neutralization test finally proved that the serum can neutralize the virus to absorbing on the cells; the PrM g-Egene nucleotide sequences amplified (439bp) from the isolated strain. we confirmed that thist wo isolates belong to JEV.The isolation was identified as the CZ-1 and NJ-1 strain of JEV.2. Biological characterization of Japanese encephalitis virusThe studies of physical and chemical properties about two strains showed:The isolate were sensitive to Aether,Chloroform and Trypsin,sensitive to acid and base, They will be sensitived above pH 3.0 and below pH 5.0. the virus was inactivated 60℃for 60min,100℃for3min. The other feature ofCZ-1 strain and NJ-1strain is thatcontaining peplos, could agglutinating red blood cell of pigeon. The TCID50 of CZ-1 and NJ-1is respectively 10-6.206/0.025ml,10-5.225/0.025mLThe lethal rate of these isolates was 100 percent when inoculating 3-5-day-old Suckling mice. The neuroinvasiveness (subcutaneous virulence) tested in the 9-11g mice had shown a lit tle difference, but when tested in t he 12-14 g mice,the difference was apparent. With biopsy we observed that, in addition to nerve cells were damaged, the organs and tissues have a variety of serious injury by Japanese encephalitis virus.