Study on the molecular characteristics of Japanese encephalitis virus living in vector mosquitoes, in Zhejiang province, 2009-2010 / 中华流行病学杂志

Objective To investigate the molecular characteristics of Japanese encephalitis virus (JEV) living in vector mosquitoes,from Zhejiang province.Methods A total of 13620 mosquitoes were collected from the monitoring stations located in Cixi city and Xianju county in Zhejiang province,in July and August,2009-2010.Nucleic acid of JEV from the mosquitoes was monitored by using real-time RT-PCR.The virus strains were isolated with BHK-21 cell line,with E genes of the isolated viruses amplified,sequenced and their phylogeny and homology analyzed.Results The positive rates of JEV for those mosquitoes collected in the stations of Cixi and Xianju were 17.0％ (27/159) and 3.4％ ( 1/29 ),respectively.Twenty-two JEV strains were isolated,accounted for 15.4％ among the 143 batches of mosquitoes collected in 2010.All E genes in the 6 sequenced virus isolates contained 1500 nucleotides encoding 500 amino acids,in which no inserts and deletions were identified.The identity rates of nucleotide and amino acid in E gene were 99.2％-99.8％ and 100.0％ among the 6 JEV strains isolated from Zhejiang,99.1％-99.3％ and 99.2％-99.8％ between the Zhejiang strains in 2009-2010 and the Zhejiang strains in 2007-2008,respectively,87.6％-88.0％ and 97.8％ between the 6 Zhejiang strains and the vaccine strain SA 14-14-2 of JEV,respectively.The phylogeny tree of E gene indicated that the JEV isolates in Zhejiang during 2009-2010 was located in the branch of the genotype Ⅰ.Conclusion Mosquitoes collected from Cixi and Xianju areas carried JEV,with the rate of JEV in Cixi higher than in Xianju.All the Zhejiang isolates in 2009-2010 were proven to be the genotype Ⅰ of JEV.

The distributions of mosquito vectors carrying Japanese encephalitis virus in Zhejiang province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the natural infection and genotype of Japanese encephalitis virus in mosquitoes and swine in some areas of Zhejiang province.</p><p><b>METHODS</b>Samples of mosquitoes and sera of swine were collected in three counties (Xianju, Longquan and Cixi) of Zhejiang province from May to October in 2007. 10 662 mosquitoes were collected during 2007, of which, C.pipiens pallens and C.quinquefasciatus were the most dominant species and 204 pig serum samples were detected. Japanese encephalitis virus in mosquitoes were detected by virus isolation and real time RT-PCR. The antibody against Japanese encephalitis virus in swine was detected by ELISA. The isolated strain were identified by real time RT-PCR. The PrM gene of the isolated strain was amplified by RT-PCR. Three strains were typed by the gene of PrM.</p><p><b>RESULTS</b>Seven positive mosquitoe samples were identified by real time RT-PCR. Three strains were isolated and identified by real time RT-PCR. The PrM gene was cloned and sequenced. The phylogenetic analysis showed that three isolates belong to genotype I of Japanese encephalitis virus. Of 204 swine serum samples, 121 positive samples were identified positives. Above 50% sera samples from swine were positive in June.</p><p><b>CONCLUSION</b>The vector of Japanese encephalitis virus existed and carried the Japanese encephalitis virus in these areas of Zhejiang province. Three strains of Japanese encephalitis virus were isolated from mosquito pools collected in Zhejiang province. It should be the first isolation of genotype I Japanese encephalitis virus in Zhejiang province in recent years.</p>

Isolation and identification of Japanese encephalitis virus from mosquitoes in Zhejiang province / 中华流行病学杂志

Objective To study the situation of arboviruses carried by mosquitoes in Zhejiang province.Methods Mosquitoes were collected from Zhejiang province in 2007.Virus strains were isolated by the inoculation of homogenates of the mosquitoes onto BHK-21 cell line.The isolated strains were identified by serological(IFA)and molecular methods(RT-PCR).Results Two strains were isolated from mosquitoes causing cytopathogenic effect(CPE)in BHK-21 cells.Results from serological tests showed that both of the two strains were positive for the antibody to Japanese encephalitis virus(JEV).PrM and E gene were then cloned and sequenced.Results from the phylogenetic analysis showed that the isolates belonged to genotype Ⅰ JEV while through sequence analysis it showed that the homology of nucleotide sequences and amino acid sequences between the two strains were 99.0% and 98.8% respectively.Compared with the JEV vaccine strain SA14-14-2 and two strains,the homology of nucleotide sequences Was up to 87.7% and homology of amino acid sequences was up to 96.4%.When comparing with the vaccine strain SA14-14-2,there were 14 common amino acid variations in all the two strains.Conclusion Two strains of JEV were isolated from mosquitoes collected in Zhejiang province whiCh was the first isolation of genotype Ⅰ JEV in the province in recent years.