Screening And Research On Common Pathogens Of Viral Encephalitis In Some Regions Of Fujian Province,2010-2011

Fujian province is one of the endemic zones of Japanese encephalitis. Many cases of viral encephalitis were found each year. In order to survey the arbovirus and infection rates in mosquitoes, and the variety of common pathogens of local viral encephalitis, the systematic and comprehensive investigation of mosquitoes, unexplained fever and encephalitis cases were carried out in Fujian Province. The results can provide basic information for prevention and diagnoses of unknown fever cases in Fujian.At the first, total of8927mosquitoes were collected from Sanming, Nanping, Fuzhou and Longyan in Fujian province,2010-2011, and divided into179pools. Main species were Culex tritaeniorhynchus and Anopheles sinensis.304serum samples from cases of acute phase,15serum specimens from cases of recovery and79cerebrospinal fluid samples from383unknown fever and encephalitis cases collected in Nanping, Fuzhou and Longyan in Fujian province,2010.Second, screening virus from mosquitoes: Mosquito pools were grinded using a Tissue Lyser, viral RNA was extracted from supernatant using Trizol LS Reagent, cDNA was synthesized using a Ready-to-Go You-Prime First-Strand Beads Kit. The RT-PCR detection for5JEV(PrM) sequences, and further study showed that the positive JEV sequences were belonging to genotypel. Meanwhile, no virus was isolated following the homogenized samples were inoculated to monolayers of BHK-21and C6/36cells.Third, full-length genome amplification and sequense analysis:One full genome, named FJ-JY-10-73, was sequenced in positive specimens by using specific primers for full-length genome of genetype1JEV.The sequence splicing and the differentiation analysis for nucleotides, deduced amino acid sequence and phylogenetic tree were performed by the software of ATGC, Clustal X (1.83), MegAlign, GeneDoc3.2and Mega (4.0). The full length of FJ-JY-10-73, with typical feature of genetype1JEV,.is10965nt, and similar to other strains in Zhejiang province, Shanghai, Taiwan, Shandong province and Liaoning province. And the homology of nucleotide and amino acid with vaccine strains SA14-14-2are88.6%and97.5%, respectively. Fourth, estimate the JEV infection rate in mosquitoes:Minimum infection rates(MIR) were estimated by using maximum likelihood estimate (MLE).The infection rate of JEV in mosquitoes in Sanming, Jianyang and Fuzhou were0.125%,0.176%and0.065%,respectively. The results indicate that the mosquito infection rates of Japanese encephalitis virus are low in Fujian Province.Fifth, screenning common pathogens of VE from case’s specimens:IgM antibodies and nucleic acids were screened and examined for the common pathogens including Japanese encephalitis virus (JEV), Enteric-cytopathogenic Human Orphan virus (ECHOV), Coxsackie virus (CoxV), Herpes simplex virus (HSV) and Mumps virus (MV) in samples from383unexplained fever and encephalitis case. The results showed that73IgM antibody positive cases (19.06%) were found, and the most common pathogen was ECHOV and CoxV (47cases,12.27%), followed by MV (11cases,2.87%), JEV (9cases,2.35%), and HSV (6cases,1.57%). At the same time,7nucleotides of ECHOV\CoxV were detected and1ucleotide of HSV were detected in79JEV negative of CSF specimens using PCR and RT-PCR.It was the first time that the common pathogens of VE were screened systematically and comprehensively in Fujian Province, as well as, the full-length genome of genotype1JEV (FJ-JY-10-73) was obtained successfully in Fujian province. And the isolated virus was similar to other strains in Eastern seaboard of our country. It is indicated that Genotype1JEV is the main genotype in mosquitoes in Fujian province, and genotype1JEV is displacing genotype3which is the main genotype in the past. The pathogenic species of VE was ECHOV and CoxV, MV, JEV, and HSV, in Fujian; and there were a typical adult(21-60years old) and children(1-5years old) epidemic, started during July-August and without obvious characteristics of regional distribution in some regions of Fujian province. The results can provide basis of prevention and control for local VE, especially for JE.