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Objective@#To analyze molecular feature of rabies virus (RABV) epidemic strains in Sichuan province during 2011 to 2017, and explore differences at nucleotide, amino acid and protein modification between these street strains and vaccine strains.@*Methods@#Nucleoprotein(N) and glycoprotein(G) genes were amplified by RT-PCR using specific primers for 23 antigen-positive canine brain specimens collected from 2011 to 2017. The evolutionary relationship and immune antigenicity of N and G genes was analyzed. Bioinformatics software was used to analyze and organize data.@*Results@#We obtained the N and G genes sequences of 23 RABV strains by sequencing. Genetic evolution relationship analysis showed that all the 23 RABV strains belonged to rabies virus species and could be divided into three branches, which had apparent geographically specific characteristics but some Sichuan strains co-circulated with the epidemic strains in the eastern and northern regions of China.The N genes of Sichuan strains had nucleotide and amino acid homology of 97.4% to 100% and 99.6%-100%. The nucleotide and amino acid homology between Sichuan strains and reference strains were 72.1%-99.8% and 81.6%-100%, respectively. There were some differences in antigenic sites, cell epitopes and signal peptide sequences between vaccine strain and Sichuan strains but no significant change was found in antigenicity, organizational preference and virulence.@*Conclusions@#The 23 strains of RABV of Sichuan belonged to rabies virus species and had no obvious differences. There were few differences between Sichuan strain and vaccine strain in amino acid sequences of G, but the virulence did not change.
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Objective To investigate the distribution patterns of mosquitoes,midges and related arboviruses in Sichuan province.Methods Blood-sucking insects were collected from houses and pens,using the ultraviolet lights.Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen.All samples were incubated with BHK-21 and C6/36 cells for virus isolation and then detected for their viral genes.Sequences of the virus were identified and analyzed by molecular biological software,such as BioEdit 7.0.5.3,MEGA 6.0.Results In total,17 019 mosquitoes from 3 genera and 4 species and 12 700 midges were collected from the southeast regions of Sichuan province in 2016 and 2017.Among them,79.4％ (13 519/17 019) belonged to Culex tritaeniorhynchus with 11.1％ (1 897/17 019) as Armigeres subalbatus,5.5％ (930/17 019) were Anopheles sinensis and 4.0％ (673/17 019) were Anopheles sinensis 3 virus strains that isolated from Culex tritaeniorhynchus were identified as type Ⅰ Japanese encephalitis virus.Seven pools of mosquitoes isolated from Hejiang county were identified Japanese encephalitis virus gene positive through PCR amplification.With 4 pool midges were detected positive for Akabane virus through PCR gene amplification while midges samples didn't have virus isolates.Conclusions Culex tritaeniorhynchus appeared the predominant species in the southeast regions of Sichuan.Japanese encephalitis virus transmitted by mosquitoes and Akabane virus by midges were prevalent in southeast Sichuan province.
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Objective To investigate the distribution patterns of mosquitoes,midges and related arboviruses in Sichuan province.Methods Blood-sucking insects were collected from houses and pens,using the ultraviolet lights.Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen.All samples were incubated with BHK-21 and C6/36 cells for virus isolation and then detected for their viral genes.Sequences of the virus were identified and analyzed by molecular biological software,such as BioEdit 7.0.5.3,MEGA 6.0.Results In total,17 019 mosquitoes from 3 genera and 4 species and 12 700 midges were collected from the southeast regions of Sichuan province in 2016 and 2017.Among them,79.4％ (13 519/17 019) belonged to Culex tritaeniorhynchus with 11.1％ (1 897/17 019) as Armigeres subalbatus,5.5％ (930/17 019) were Anopheles sinensis and 4.0％ (673/17 019) were Anopheles sinensis 3 virus strains that isolated from Culex tritaeniorhynchus were identified as type Ⅰ Japanese encephalitis virus.Seven pools of mosquitoes isolated from Hejiang county were identified Japanese encephalitis virus gene positive through PCR amplification.With 4 pool midges were detected positive for Akabane virus through PCR gene amplification while midges samples didn't have virus isolates.Conclusions Culex tritaeniorhynchus appeared the predominant species in the southeast regions of Sichuan.Japanese encephalitis virus transmitted by mosquitoes and Akabane virus by midges were prevalent in southeast Sichuan province.
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Objective@#To study the genome molecular characteristics of Getah virus (SC1210) which isolated in Sichuan province in 2012.@*Methods@#Reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify the isolate and the genome was sequenced by the second Ion Torrent PGM. Computer softwares, including Mega Align and Mega 6, were used to analyze the nucleotide and deduced amino acid sequence, and draw phylogenetic trees.@*Results@#SC1210 was identified as Getah virus. The full genome sequence was 11 690nt, the nucleotide and amino acid homology of the full sequence with other strains were 99.2%-99.7% and 96.5%-99.4%.The capsid protein of SC1210 consisting of 804 nucleotides, encoding 268 amino acids and the full-length of E2 protein, had 1 266 nucleotides, encoding 422 amino acids. The nucleotide homology of the capsid protein and the E2 protein with other strains were 94.9%-99.2% and 94.6%-99.6%, and the amino acid were 97%-99.6% and 97.1%-99.5%. The 3′ UTR of the virus included 402 nucleotides and there were three repeat sequence elements and 19 nucleotides conservation sequence.@*Conclusions@#The first GETV isolate SC1210 in Sichuan province has a closer relationship with Yunnan strain YN040 and a far genetic relationship with MM2021.
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Objective To analyze the genotype of Japaneso encephalitis virus (JEV) strains isola-ted in 2004 from mosquitoes collected in Bazhong city, Sichuan province of China, and the characters of amino acid in the PrM and E gene. Methods The isolated virus strains from mosquitoes were identified by biological, serological and molecular biology. PrM and E segments of the isolated JEV were amplified by RT-PCR, the PCR products were purified and sequenced. Multiple alignment, phylogenetic and amino acid (AA) analysis were carried out by Clustal X (1.8) , MEGA4 and GENEDOC (3.2) . Results The total of 4688 mosquitoes were collected including Armigeres and Culex. Six isolates were identified be-longing to genotype 1 JEV. The comparison between new genotype 1 JEV strains and live attenuated vaccine strain SA14-14-2 in PrM and E gene showed that total 3 sites amino acid differences in PrM gene and 14 sites in E gene, respectively. Three sites (PrM2, 64 and 65 ) in PrM protein and four sites (E129, 222,327 and 366) in E protein were only belonging to genotype 1 JEV. Conclusion The new isolated JEV strains in Sichuan province belong to genotype 1. It suggests that the vaccine strain SA14-14-2 currently used for preventing Japanese encephalitis is able to protect people against JEV, although in the segments of it had some amino acid differences between vaccine strain and the epidemic genotype 1 JEV strains in PrM and E gene.