Comparison of viremia formation between guinea-pigs infected with wild and attenuated (SA14-14-2) Japanese encephalitis viruses / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the viremia formation in guinea-pigs infected with wild type and attenuated Japanese encephalitis virus (JEV).</p><p><b>METHODS</b>Guniea pigs were inoculated intraperitoneally with different wild JEV strains and the attenuated vaccine strain and its parent virulent strain. Viremia was detected on different days following virus inoculation.</p><p><b>RESULTS</b>All the guinea-pigs inoculated with the wild JEV strains induced different levels of viremia (1.00-3.40 Lg pfu) on the 1st and 3rd day post inoculation. Using a virus titer of 10(4) pfu for inoculation, the animals inoculated with the SA14 parent strain induced relatively high viremia (10(2.4)-10(3.4) pfu), however no viremia coulds be detected on any tested days.</p><p><b>CONCLUSION</b>The degree of viremia in guinea pigs can be used as a new method to evaluate the attenuation of JEV.</p>

Study on the phenotypic characteristics of Japanese encephalitis virus strains isolated from different years / 病毒学报

In order to reveal the phenotypic characteristics of 17 JE virus strains isolated from different years, plaque sizes, mice neurovirulence and mice neuroinvasiveness of the isolates were studied and compared. BHK21 cell monolayers were used for testing the plaque sizes. The virus neurovirulence was tested in 9-11g mice inoculated intracerebrally and the virus neuroinvasiveness was tested in 9-11g and 14-16g by subcutaneous inoculation. Results showed that all the viruses produced clear plaques on the BHK21 cell monolayers with different sizes and all the virus strains appeared high neurovirulence in the mice with higher than lg8. 0/0.03 mL virus titers, while no apparent difference among them. The neuroinvasiveness (subcutaneous virulence) tested in the 9-11g mice had shown a little difference, but when tested in the 12-14 g mice,the difference was apparent. The results demonstrated that JEV in nature were highly neurovirulent with no apparent difference. However the neuroinvasiveness of the JEV in nature was greatly different, which didn't relate to the years of isolation and genotypes, but most of the viruses isolated from patients showed higher neuroinvasiveness.