Evaluation of environment safety of a Japanese encephalitis live attenuated vaccine

Publication date: Available online 7 June 2019Source: BiologicalsAuthor(s): Xinyu Liu, Lili Jia, Kaixiao Nie, Danhua Zhao, Rui Na, Hongshan Xu, Gong Cheng, Junzhi Wang, Yongxin Yu, Yuhua LiAbstractJE vaccination is the most effective and economical method of preventing JE. A live attenuated JE vaccine has been widely used in many countries since 1989, playing an important role in controlling JE outbreaks. However, whether the large-scale use of the live attenuated JE vaccine will lead to the dissemination of the vaccine virus in the environment and whether reversion of the neuroattenuation of the virus will occur during the transmission process remain major concerns for some researchers. To evaluate the transmission of a live attenuated JEV vaccine in mosquitoes and hosts, JE SA14-14-2 attenuated vaccine virus was intrathoracically (i.t.) inoculated into Culex tritaeniorhynchus, a native vector. Subsequently, virus harvested from inoculated mosquitoes was inoculated into pigs, a mammalian reservoir. The virus was isolated from the pigs and passaged once again in Culex tritaeniorhynchus. The genome sequences and virulence of the passaged viruses were then investigated. While a few nucleotide substitutions occurred during passaging, there was no change in the encoded amino acids. After intracerebral (i.c.) inoculation of mice with the vaccine, no pathological effects were observed. In addition, virus virulence remained low after inoculation of suckling mouse brains. These resul...
Source: Biologicals - Category: Biology Source Type: research