The West Nile virus (WNV), a mosquito-borne arbovirus, is also a zoonotic pathogen first isolated in the 1930s in Africa, followed by the identification of the prevalence of febrile illness caused by West Nile virus infections. In 1999, the West Nile virus was first introduced into New York City of the United States, and caused the outbreak of viral encephalitis in adults. This marked the first reported outbreak of mass adult viral encephalitis caused by West Nile virus. Subsequently, West Nile virus and its infections in humans and animals spread rapidly throughout the United States, causing a worldwide sensation. West Nile virus is currently considered the most widely distributed emerging mosquito-borne arboviruses worldwide. Humans or animals infected by mosquito bites can develop symptoms such as fever, encephalitis (meningitis), and in rare cases, present with severe pancreatitis, hepatitis, myocarditis, miscarriage, or even death, posing a huge global public health burden. This review introduces China's progress in the isolation and identification of West Nile virus, the prevalence of adult viral encephalitis, and the field surveys and laboratory investigations of the coinfection of West Nile virus and typhoid bacteria, aiming to promote the research work and control and prevention of West Nile virus and its infection in China.

Abstract： Objective　To elucidate the antigenic antibody reaction of recombinant expression of non-structural protein 1 (NS1) of Japanese encephalitis (JE) virus with various mosquito-borne flaviviruses, including JE virus, and the antigenic antibody reaction of serum samples of patients infected with JE virus in acute stage. Methods　In this study, Escherichia coli prokaryotic expression vector (pET) system was used to recombinant express Japanese encephalitis virus NS1 gene. Western Blot assay was performed to detect the antibody responses of the recombinantly expressed protein against a variety of mosquito-transmitted flaviviruses, including JE virus, as well as antigen-antibody reactions of serum from patients with acute JE virus infection. Results　The NS1 gene expression product of JE virus (P3 strain) was in the form of an inclusion body, and the denatured and renatured expression product was displayed as a single band in the denatured gel (polyacrylamide gel electrophoresis, PAGE), with a molecular weight of about 45 000. The results of further antigen-antibody analysis showed that the antigen/antibody hybridization reaction of the expression product with polyclonal or monoclonal antibody of JE virus (mosquito isolates, encephalitis isolates) and serum samples of patients with acute JE virus infection could be completely consistent. The recombinant product showed negative antigen/antibody hybridization reactions with mosquito-transmitted flaviviruses, such as dengue virus and yellow fever virus polyclonal antibodies, but positive reactions with polyclonal antibodies to West Nile virus and Murray Valley encephalitis virus. Conclusions　In this study, the recombinant expression of the NS1 protein of JE virus was successfully obtained, and the antigen/antibody reaction between the recombinant protein and samples of patients infected with mosquito-borne flavivirus and JE virus was analyzed. The study results provide important basic data for elucidating the antigen-antibody reaction between the NS1 protein of JE virus and mosquito-borne flavivirus. The recombinant expression protein obtained in this study provides an important material basis for further research on the function of JE virus NS1 protein.

Objective:This study contrasts the immune efficacy of the varicella zoster virus glycoprotein E (VZV gE)using Al/CpG combined adjuvants and AS01 adjuvant in BALB/c mice.Methods:BALB/c mice were immunized at 0 and 21 days respectively, and serum antibodies were detected using enzyme-linked immunosorbent assay. Detection of neutralizing antibodies in mouse serum using varicella zoster virus; enzyme-linked immunosorbent spot assay was used to detect cellular immune response.Results:Following two intramuscular immunizations, mice in the experimental groups (Shingrix, gE+ Al/CpG, and gE+ AS01) demonstrated elevated neutralizing antibody titers and an augmented count of lymphocytes releasing IFN-γ and IL-4. The gE+ Al/CpG group displayed the highest neutralizing antibody titer (1943), yet the AS01-adjuvanted groups (Shingrix and gE+ AS01) showed increased lymphocyte counts secreting IFN-γ and IL-4 compared to the Al/CpG group (gE+ Al/CpG). In comparison to the AS01 adjuvant, Al/CpG adjuvants triggered a humoral immune response favoring Th2 in mice. The proportions of CD4 + T and CD8 + T cells were not significantly different among the experimental groups. Conclusions:Al/CpG adjuvant combined with gE protein resulted in high neutralizing antibody titers, while the intensity of the induced cellular immune response was inferior to that of AS01 adjuvant.

Objective:To establish a sensitive and specific real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) method for rapid detection of Getah virus (GETV).Methods:All the gene sequences of GETV were downloaded from GenBank database. Clustal X was used for sequence alignment, and specific primers and probes were designed according to highly conserved regions; we established a standard curve using the nucleic acid of GETV as a standard, and the sensitivity, specificity and stability of this method were evaluated respectively.Results:This method could specifically detect GETV and has no cross-reactivity with multiple arboviruses; the sensitivity was 1.0×10 pfu/ml, and the intra-assay and inter-assay coefficients of variation were less than 1%. One case was GETV positive in 196 batches of mosquitoes collected from Hunan province, Hebei province, Fujian province and Chongqing city.Conclusions:We established a TaqMan probe real-time quantitative RT-PCR with high sensitivity and specificity which can be used for screening.

Objective To investigate the effect and mechanism of suberoylanilide hydroxamic acid (SAHA) on the fear extinction in mice with chronic social defeat stress (SD). Methods Fifty-six male C57BL/6J mice aged 7-8 weeks were randomly divided into control group,social defeat group,control-SAHA group and social defeat-SAHA group to investigate the effect of SAHA and social defeat group,social defeat-AAV BDNF group and social defeat-AAV blank group to investigate the effect of BDNF. Fear extinction in mice was evaluated by fear conditioning test (FC). The levels of BDNF and HDAC2 in mice hippocampus were detected by Western blot (WB). The expression of BDNF-overexpressing virus in hippocampus of mice was detected by immunofluorescence assay. Results (1) Compared with control group,fear extinction in the social defeat group was significantly decreased (P<0. 05). Compared with control group, the level of HDAC2(0. 50±0. 02) in the social defeat group was significantly increased (P<0. 001),while the level of BDNF(0. 16 ± 0. 03) was significantly decreased (P<0. 001) in the social defeat group. ( 2) After using SAHA,fear extinction of mice significantly improved (P<0. 05). Compared with control group,the level of HDAC2 (0. 26±0. 02) in the control-SAHA group was significantly decreased(P<0. 001),and the level of BDNF (0. 40±0. 03) was significantly increased (P<0. 001). Compared with social defeat group,the level of HDAC2 (0. 39±0. 03) in the social defeat-SAHA group was significantly decreased (P<0. 001),and the lev-el of BDNF (0. 28±0. 01) was significantly increased (P<0. 001). (3)After injection BDNF-overexpressing virus,fear extinction was significantly improved(P<0. 05). Conclusion SAHA can enhance fear extinction in mice with chronic social defeat stress and its mechanism may be related to the up-regulation of BDNF ex-pression in hippocampus by inhibiting HDAC2 in hippocampal.

Objective:In this study, the collected mosquito samples were subjected to viral isolation to identify the species and branch characteristics of arboviruses in five regions of Shanxi Province.Methods:Eight arboviruses in mosquito samples collected from July to September 2020 were detected by real-time fluorescent quantitative PCR, and virus isolation was carried out through cell culture. Virus isolates were identified and analyzed by molecular biology and bioinformatics method.Results:We detected 1 batch of positive samples of Japanese encephalitis virus, 2 batches of positive samples of Culex flavivirus and 8 batches of positive samples of Nam Dinh virus among 121 batches of mosquito samples. Seven virus isolates were isolated, numbered: SX-YJ-Cxp-4、SX-YJ-Ars-2、SX-YJ-Cxp-1、SX-LY-Cxp-10、SX-GP-Ars-5、SX-GP-Cxp-2、SX-GP-Cxp-4, all of which were identified as Nam Dinh virus, and the whole genome sequencing was performed on one of them, and the result showed that Shanxi Nam Dinh virus isolate and Yunnan Nam Dinh virus isolate belonged to the same evolutionary branch.Conclusions:Nam Dinh virus was isolated and identified on the specimen from Shanxi province for the first time.

Objective:To determine the evaluation indexes of national standard strains of genotypes 1, 3 and 5 of Japanese encephalitis virus (JEV) and evaluate the national standard JEV strains.Methods:According to the national standard strain evaluation technical standards of pathogenic microbial bacteria (virus) species, based on the application of Japanese encephalitis virus research, and according to the morphological characteristics, biological characteristics, molecular biological characteristics and other research data to identify the characteristics of G1, G3 and G5 genotypes of JEV.Results:Spherical virus particles with a diameter of about 60 nm were visible under electron microscope of the three Japanese encephalitis virus strains. The cytopathic effect was mainly characterized by cell shrinkage and exfoliation in BHK-21 and Vero cell lines, cell fusion and exfoliation were shown after infection with C6/36 cell line; the virus titer was 10 5-10 7 PFU/ml, and the plaque size was different by genotype. The median lethal dose of intrabitoneal challenge in G1, G3 and G5 JEV in three weeks-old mice was 50.51 PFU, 6.98 PFU, and 8.13 PFU, and the median lethal dose of intracranial challenge in five weeks mice was 3 PFU, 0.3 PFU, 1.35 PFU. The whole genome length of G1, G3 and G5 JEV was 10 967 bp, 10 976 bp and 10 983 bp, respectively. Conclusions:Three genotypic national standard strains of JE V were identified and evaluated by electron microscopy, cell, animal and genome laboratory indexes, which provided reference for the identification and evaluation of other national standard strains of JEV.

In 2008, Japanese encephalitis (JE) vaccine was included as Expanded Program on Immunization (EPI) for children(under 15)in China, and the number of JE cases of children was greatly reduced. However, since 2006, there have been outbreaks of adult JE in northern China, which has formed a huge public health burden on the local area and caused wide attention from the society. In addition, a number of adult JE have appeared in Japan, South Korea, Malaysia and other countries, and adult JE has become a public health concern at abroad. This paper introduces the current situation of adult JE both China and abroad, and discusses the relevant issues of the prevention and control of adult JE.

Objective:To establish a rapid method for the detection of varicella-zoster virus (VZV) by recombinase-aid amplification (RAA).Methods:The whole genome sequences of VZV were downloaded from the global shared database for comparison and analysis. Specific primers and probe were designed for the four conserved genes respectively and the optimal combination was selected. The optimal reaction system was selected through the concentration gradient of primers and probes, and a fluorescence RAA detection method was established. The sensitivity of the method was evaluated with VZV positive plasmid standard and clinical samples with gradient dilution, the repeatability of the method was evaluated with the lowest detectable limit concentration of positive plasmid standard, and the specificity of other viral nucleic acid method was evaluated. At the same time, this method and quantitative real-time PCR (qPCR) were used to detect clinical samples and the result were compared.Results:The optimal combination of primer pair F2/R2 and probe P2 targeting open reading frame (ORF) 28 gene was selected. Considering the cost factor, the optimal primer concentration was set at 500 nmol/L and the optimal probe concentration was 280 nmol/L. The minimum detection limit was 10 1 copies/μL, and the minimum clinical positive samples with a Ct value of 36.027 could be detected, and the result of repeated experiments were consistent. The method has no cross-reaction with other viral nucleic acids. The detection rate of clinical positive samples was 93.33%, which was almost identical to that of qPCR. Conclusions:This method is simple to operate with high sensitivity, strong specificity, low requirements for experimental conditions, visual detection result, and can detect VZV nucleic acid in samples within 20 minutes, which is a rapid VZV detection method that can be considered for clinical use for detection.

Objective Genotypes(G)1,3,and 5 of the Japanese encephalitis virus(JEV)have been isolated in China,but the dominant genotype circulating in Chinese coastal areas remains unknown.We searched for G5 JEV-infected cases and attempted to elucidate which JEV genotype was most closely related to human Japanese encephalitis(JE)in the coastal provinces of China. Methods In this study,we collected serum specimens from patients with JE in three coastal provinces of China(Guangdong,Zhejiang,and Shandong)from 2018 to 2020 and conducted JEV cross-neutralization tests against G1,G3,and G5. Results Acute serum specimens from clinically reported JE cases were obtained for laboratory confirmation from hospitals in Shandong(92 patients),Zhejiang(192 patients),and Guangdong(77 patients),China,from 2018 to 2020.Seventy of the 361 serum specimens were laboratory-confirmed to be infected with JEV.Two cases were confirmed to be infected with G1 JEV,32 with G3 JEV,and two with G5 JEV. Conclusion G3 was the primary infection genotype among JE cases with a definite infection genotype,and the infection caused by G5 JEV was confirmed serologically in China.