Investigation on neutralizing antibody level of Japanese encephalitis virus in adults from Guizhou Province / 中华疾病控制杂志

@# Objective To investigate the level of neutralizing antibodies against Japanese encephalitis (JE) virus in adults from Guizhou Province. Methods A multi-stage random sampling method was used to collect 360 serum of healthy adults in 6 age groups of 3 cities (states) from May to June 2017. Neutralizing antibodies against Japanese encephalitis virus of healthy adults were detected by plaque reduction neutralization test. Results The positive rate of neutralizing antibodies against Japanese encephalitis virus was 55.28%, and the geometric mean titer (GMT) was 1 :17.52 in 360 subjects. The difference of the positive rates of neutralizing antibodies against Japanese encephalitis virus of adults in different genders(2=10.798, P=0.001) and in different incidence regions(2=6.090, P=0.048)was statistically significant(both P<0.05). The positive rate of different age groups was 45.00%-60.00%(2=4.236, P=0.516). The positive rate of Buyi nationality was the highest (79.17%). Conclusions The level of neutralizing antibodies against Japanese encephalitis virus of adults in Guizhou province is low, and there is a risk of epidemic encephalitis in adults.

Molecular characteristics of the genome of G I of Japanese encephalitis virus isolated from the specimen collected from viral encephalitis case for the first time / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the molecular basis of pathogenicity of Japanese encephalitis virus (JEV) by sequencing of complete nucleotide sequence and analyze the characteristics of full-length genome of genotype I Japanese encephalitis virus strains (GZ56) which was isolated from the first cerebrospinal fluid (CSF) of Japanese encephalitis patients.</p><p><b>METHODS</b>The complete nucleotide sequence was obtained by RT-PCR and sequencing was performed directly. Bioinformatics was used to analyze the nucleic acid data, deduced amino acid sequence and phylogenetic trees.</p><p><b>RESULTS</b>The result of sequence analysis showed that the genome of GZ56 strains had 10 965 nucleotides, which coded for a 3432-amino acid polyprotein. Phyolngenetic analysis based on full-length genome showed that GZ56 strains and M-28 strains which were the first isolated from mosquitoes in Yunnan in 1977 were in the same evolutionary branch. GZ56 strains belongs to genotype I of Japanese encephalitis virus, the homology of genome ranged from 96.2% to 98.6% in nucleotide and from 98.2% to 99.7% in amino acid sequences respectively when compared with selected genotype I of JEV strains in GenBank. There were 11 amino acid divergences in E protein when compared with the JEV inactivated P3 strain but they are not the key virulence sites. However, there were 14 amino acid divergences in E protein when compared with the JEV live attenuated vaccine SA14-14-2 strain and 8 amino acid divergences were the key virulence sites.</p><p><b>CONCLUSION</b>This study indicated that the full length of genome GZ56 strains had no ignificant change. It can be hypothesized from genomic level that the currently available JEV vaccines(inactivated and live attenuated) can protect against GZ56 strains infection, meanwhile, the JEV live attenuated vaccine (SA14-14-2) formulation conferred higher levels of protection.</p>