Isolation and identification of a distinct strain of Culex Flavivirus from mosquitoes collected in Mainland China.

BACKGROUND: Culexflavivirus (CxFV) is an insect specific virus that has been isolated from Culexpipiens, Culexquinquefasciatus, Culextritaeniorhynchus and other Culex mosquitoes. It is a novel flavivirus isolated in Asia, North America, Central America and Africa. Phylogenetic analysis indicates that, based on the envelope gene (E gene) sequence, the worldwide CxFV strains can be divided into two genotypes. RESULT: A virus (SDDM06-11) was isolated from Culexpipiens collected in Shandong Province, China in 2006. The strain caused cytopathic effect (CPE) in Aedesalbopictus (C6/36) cells by 3 days post-infection and immunofluorescence assay (IFA) showed a reaction with Japanese encephalitis virus (JEV) polyclonal antibodies. Phylogenetic analysis of the E gene sequence showed CxFV formed two genotypes with the SDDM06-11 strain assigned to genotype 1. Analysis of the E gene nucleotide homology showed the virus possessed characteristic amino acids at specific sites. The nucleotide homology of the open reading frame (ORF) was 94.8%-95.1% between SDDM06-11 and isolates from Japan, Iowa and Texas, and 90.2%-90.5% between SDDM06-11 and isolates from Uganda and Mexico. CONCLUSION: In this paper we report the first isolation and identification of an isolate of CxFV in mainland China. Phylogenetic analysis indicates the isolate belongs to genotype 1. Our findings provide insight into the occurrence of CxFV in Culex mosquito populations and its distribution on a global scale.

Etiological spectrum of clinically diagnosed Japanese encephalitis cases reported in Guizhou Province, China, in 2006.

The proportion of laboratory-confirmed Japanese encephalitis (JE) virus (JEV) infections was compared to the number of JE cases reported on the basis of seasonality and the clinical symptoms of hospitalized patients in Guizhou Province, China, between April and November 2006. Of the 1,837 patients with reported JE, 1,382 patients in nine prefectures were investigated. JE was confirmed in 1,210 of 1,382 (87.6%) patients by a JEV-specific immunoglobulin M (IgM) antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA), heminested reverse transcriptase PCR, and virus isolation. Two strains of JEV belonging to genotype 1 were isolated. Other viral pathogens responsible for encephalitis, including echovirus, mumps virus, herpes simplex virus, and cytomegalovirus, were identified in 67 of 172 (38.9%) JE-negative cases. On the basis of the distribution of the laboratory-confirmed JE cases from different hospitals according to the Chinese administrative division, which included hospitals at the provincial, city, county, and township levels, county hospitals detected the highest number of JE cases (81.8%), whereas township hospitals detected the smallest number of JE cases (1.4%). Provincial and city hospitals had the highest and lowest rates of accuracy of providing a clinical diagnosis of JE, as confirmed by laboratory testing (91.8% and 76.7%, respectively). This study demonstrates that laboratory confirmation improves the accuracy of diagnosis of JE and that an enhanced laboratory capacity is critical for JE surveillance as well as the identification of other pathogens that cause encephalitic syndromes with clinical symptoms similar to those caused by JEV infection.

Robust humoral and cellular immune responses induced by novel DNA vaccine against West Nile virusin in mice / 中华微生物学和免疫学杂志

Objective:To evaluate the immunological efficacy of a novel DNA vaccine against West Nile virus (WNV) in a mouse model.Methods:A DNA vaccine VRC-prME expressing the precursor membrane (prM) and envelope protein (E) of WNV Xinjiang strain (XJ11129-3) was constructed and its ability to express virus-like particles was verified in vitro. C57BL/6 mice were immunized twice with VRC-prME via intramuscular injection combined with electroporation with an interval of four weeks. Enzyme-linked immunoassay (ELISA) was used to detect serum antibodies after immunization. WNV (NY99 strain) single-round infectious particles were used to detect neutralizing antibodies. Cellular immune responses were analyzed by enzyme-linked immunoblot assay (ELISPOT) and intracellular cytokine staining (ICS). Results:VRC-prME induced a strong Th1-biased antibody response in mice that could cross-neutralize the WNV (NY99 strain) single-round infectious particles two weeks after the boost immunization. Moreover, the vaccine also elicited antigen-specific multifunctional CD8 + T cell responses (IFN-γ, IL-2, TNF-α). Conclusions:The novel DNA vaccine prepared in this study, expressing the prME protein of WNV XJ11129-3 strain, could induce stronger humoral and cellular immune responses in mice, which was worthy of further research and development for the prevention of WNV infection in China.

Detection and surveillance of west nile virus infection in southern Xinjiang, China, 2012 / 中华实验和临床病毒学杂志

Objective@#To investigate the west nile virus (WNV) infection in Xinjiang, China.@*Methods@#Serum samples were collected from patients with fever and chicken in southern Xinjiang, 2012. The presence of WNV-specific immunoglobulin M (IgM) antibodies and neutralizing antibodies was examined through enzyme-linked immunosorbent assay (ELISA) and plaque reduction neutraization test (PRNT90).@*Results@#A total of 1 712 serum samples of outpatients and inpatients were collected in 8 counties in southern Xinjiang. As a result , 22 samples were positive for WNV IgM antibody and 48 samples were positive for WNV neutralization antibody, among which 21 WNV IgM antibody positive samples and 42 WNV neutralization antibody positive samples were from Jiashi county. Of 383 chicken serum samples collected in 4 counties in southern Xinjiang, only 28 samples were positive for WNV neutralizing antibody, interestingly, all positive chicken serum samples were collected from Jiashi county.@*Conclusions@#This study revealed that WNV infection occurred in human and poultry in southern Xinjiang, 2012, mainly in Jiashi county.

Investigation of tick-borne pathogens in Heilongjiang border area / 中华实验和临床病毒学杂志

Objective@#To understand the situation of ticks carrying pathogens in border areas of Heilongjiang province.@*Methods@#From 2009 to 2018, tick specimens were collected in Yichun, Daxing′anling area and Jiamusi in Heilongjiang province. A total of 2 530 ticks were studied, including 800 Ixodes persulcatus and 1 730 Dermacentor silvarum. Tick-borne encephalitis virus (TBEV), severe fever with thrombocytopenia syndrome virus (SFTSV), omsk hemorrhagic fever virus (OHFV), langat virus (LGTV), powassan virus (POWV) were detected by real-time RT-PCR. Spotted fever group rickettsia (SFGR) and Borrelia burgdorferi sensulato (B.b.s.l) were detected by PCR in ticks collected from Jiamusi area.@*Results@#All tick speciments collected were negative for TBEV, SFTSV, OHFV, LGTV and POWV. Tick specimens from Jiamusi carried SFGR and B. b.s.l.with positive rates of 59.5% and 8.9%.@*Conclusions@#The ticks in border areas of Heilongjiang province carry spotted fever group rickettsia and Borrelia burgdorferi, and the carrying rate of spotted fever group rickettsia is high. The monitoring and control of ticks and tick-borne diseases should be strengthened.

Genotype I of Japanese encephalitis virus as the dominant genotype among mosquitoes in Shandong / 中华实验和临床病毒学杂志

Objective@#To analysis the genotype of Japanese encephalitis virus (JEV) in mosquitoes from Shandong province.@*Methods@#Mosquitoes were collected between August and September in Weishan county, Junan county, and Kenli county of Shandong province in 2016. Viruses were isolated by BHK-21 cell and identified by molecular method . Real-Time RT-PCR was conducted to detect the Japanese encephalitis virus carried by the mosquitoes.@*Results@#A total of 8418 mosquitoes divided into 81 pools including 3 species, Culex tritaeniorhynchus, Anopheles sinensis and Armigeres obturbans. Eight Japanese encephalitis viruses were isolated; 23 pools were positive by JEV specific real-time RT-PCR. Phylogenetic analysis on E sequence of JEV showed all JEV strains belonged to genotype Ⅰ JEV, and new strains that were homogenous with previous JEV strains isolated from Shandong.@*Conclusions@#Genotype Ⅰ JEV was the dominant genotype in Shandong province.

Epidemiological characteristics of tick borne encephalitis in China, 2014 / 中华实验和临床病毒学杂志

Objective@#To analyze the epidemiological characteristics and distribution characteristics of tick-borne encephalitis in China in 2014, and to provide scientific basis for formulating specific prevention and control measures.@*Methods@#The epidemic data were obtained from the "infectious disease report information management system" , using Excel 2016, GIS and other software to summarize and analyze the cases of tick borne encephalitis (TBE) reported, using the number of cases, incidence, composition ratio and other indicators to analyze and describe the TBE epidemiological characteristics in China in 2014.@*Results@#In 2014, a total of 322 cases of TBE were reported in 9 provinces in China, with an annual incidence of 0.024/100, 000 and 1 death of patient. The provinces with high number of cases were Jilin province, Inner mongolia autonomous region and Heilongjiang province, and the number of cases in the other six provinces is no more than two. TBE was distributed in spring and summer, and it is concentrated in May to July. The age of the affected population was mostly concentrated in 40-49 years old, the male-female ratio was 1.6∶1 (198/124), and the patients were dominantly farmers, household and unemployed workers, and forestry workers, they accounted for 49.40% (159/322), 26.40% (85/322) and 18.60% (60/322) of the national TBE cases respectively. The three hospitals that reported the most TBE cases in 2014 were Inner mongolia forestry general hospital, Jiangyuan People′s hospital of Baishan city, Jilin province and Mudanjiang forestry central hospital of Heilongjiang province. The number of reported cases in these three hospitals accounted for 68.6% of the whole country. The laboratory diagnosis rate of Inner mongolia forestry general hospital was the highest (91.9%).@*Conclusions@#In 2014, the incidence of TBE in China has continued to rise compared with the previous two years. The geographical focus is mainly on the forest areas of Daxing′anling, Xiaoxing′anling and Changbai Mountain.

Mosquitoes, midges and related arboviruses in southeast Sichuan province / 中华流行病学杂志

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.

Mosquitoes, midges and related arboviruses in southeast Sichuan province / 中华流行病学杂志

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 typeⅠ 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.

First isolation and identification of Getah virus SC1210 in Sichuan / 中华实验和临床病毒学杂志

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.

Investigation of mosquitoes and arboviruses in the border areas of Yunnan province, 2012 / 中华实验和临床病毒学杂志

Objective@#To investigate the distribution patterns of arboviruses in Yunnan province near the China-Laos-Myanmar border, China, and to provide evidence for prevention and control of arboviruses diseases.@*Methods@#Mosquito samples were collected in Daluo county of Xishuangbanna Dai Autonomous Prefecture and Zhengdong county of Pu’er city in Yunnan province, 2012. Viruses were isolated from the samples by tissue culture, positive isolates were identified by RT-PCR with arbovirus species-specific primers, for further sequencing and phylogenetic analysis.@*Results@#A total of 17 species of mosquitoes from 6 genera were collected. A total of 24 strains of viruses were isolated from the mosquito pools and identified as Tembusu virus (TMUV) (2 strains), Japanese encephalitis virus (JEV) (3 strains), Getah virus (GETV) (2 strains), Banna virus (BAV) (4 strains), Densovirus (DNV) (9 strains) and Nam Dinh virus (NDiV) (3 strains).@*Conclusions@#The China-Laos-Myanmar border of Yunnan province is rich in species of mosquitoes and arboviruses.

Phylogenctics of Getah virus and its migration / 中国人兽共患病学报

In order to investigate the molecular evolution and spatio-temporal migration of Getah viruses (GETV) isolated around the world,the nucleotide and deduced amino acid sequence of GETVs were analyzed and phylogenetic trees were constructed by using informatics software including ClustalX1.83,MegaAlign,GeneDOC and Mega6.0.The Bayesian Stochastic Search Variable Selection (BSSVS) program in the BEAST v 1.8.1 software package was used to analyze the spatial dynamics of the Getah virus.Results showed that the full-length of Getah virus E2 gene consists of 1 266 nueleotides,encoding 422 amino acids.And the homology of nucleotide and amino acid were 94.5％ 100％ and 96.4％ 100％ respectively.The molecular evolution analysis revealed that there were no species and geographical distribution difference existing among GETV host animals (e.g.horses and pigs) and vectors (e.g.mosquitoes).Bioinformatics analysis showed that GETV originated in Malaysia,then it was spread to Japan,China,South Korea,Mongolia,Russia,etc.GETV E2 gene was relatively stable since GETV was first isolated in 1955.The differences of species and geographical distribution did not exist among GETV host animals and vectors,and the virus has spread from tropical regions to Eurasian continent.Thus,strengthening the detection and monitoring of GETV and its infections in humans and livestock is critical.

Study on Spatial Dispersal and Migration Events of Japanese Encephalitis Virus / 病毒学报

To explore the spatial distribution mechanism of Japanese encephalitis virus (JEV), PhyML v3.0 was used to build phylogenetic tree using JEV sequences in the dataset. PAUP v4.0 and Migrapyhla softz ware were then used to analyze the migration events. The results showed that a total of 95 migration events were observed during the dispersal of JEV throughout Asia. Further analysis revealed that Thailand, and several Chinese provinces (including Shandong, Shanghai, Sichuan and Yunnan), were the main migration sources of JEV. JEV spread from these migration sources as follows: from Thailand to Australia, Cambodia, Tibet and India; from Shanghai to eastern coastal Asian regions and Yunnan; from Shandong to Korea, Zhejiang, Hubei, Shanxi and Liaoning; from Sichuan mainly to inland regions of China, as well as Vietnam and Japan; and from Yunnan to Zhejiang. This study indicated that frequent migration events occurred during the dispersal of JEV in the Asia and Pacific regions, and that Thailand, Shandong, Shanghai, Sichuan and Yunnan were the sources of JEV dispersal.

Isolation and identification of the Akabane virus from mosquitoes in Yunnan Province, China / 病毒学报

To evaluate the prevalence of mosquito-borne viruses in Manshi and Ruili (Yunnan Province, China), we collected 2 149 mosquitoes (17 species) in August 2010. Virus isolation was undertaken by the cul- ture of baby hamster kidney cells (BHK-21 cells). Two virus-like isolates were obtained: DHL10M117 was isolated from collected in Mangshi; DHL10M110 was obtained from Anopheles vagus collected in Rui- li. Both isolates caused cytopathic effects,illness and death in suckling mice inoculated with these isolates via the intracerebral route. Two positive amplicons, 702-bp from the S segment and 456-bp from the M segment,were obtained using reverse transcription-polymerase chain reaction using primers specific for the Akabane virus (AKV). Phylogenetic analysis suggested that these two virus stains had a distant relation- ship with AKVs from Kenya and Australia,but were genetically close to those from Japan,South Korea, and Taiwan. However,they were separate from other Asian strains and grouped into a small branch. The highest nucleotide and amino-acid sequence identity of the S segment was found with the CY-77 strain from Taiwan (96.6% and 99.6% for DHL10M117 and 96.7% and 100% for DHL10M110,respectively). Com- parison of the M segment showed they shared the highest amino acid identity with CY-77 (99.6% and 100%, respectively), whereas the highest nucleotide identity was found with the Iriki strain from Japan (99.6% and 100%, respectively). Compared with the MP496 strain from Kenya,they displayed lower lev- els of sequence homology, at 69.7% and 70.0% for nucleotide sequences of the two loci,and 91. 0% for a- mino acids. Our results identified that DHL10M117 and DHL10M110 were strains of AKV,and provided molecular biological evidence for the existence of AKV in Yunnan Province. These AKV strains that are circulating in Yunnan Province share a close genetic relationship with strains from the rest of Asia. Culex tritaeniorhynchus and Anopheles vagus may serve as transmission vectors.

Isolation and identification of mosquito-borne arboviruses in Yuncheng city, Shanxi province, 2012 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the species and distribution of mosquitoes and mosquito-borne arboviruses in Yuncheng city of Shanxi province, China.</p><p><b>METHODS</b>Mosquito samples were collected in 19 collection sites from Linyi county and Yongji city in Yuncheng city, in August, 2012. After identification and classification, all the specimens were homogenized and centrifuged to acquire supernatant before being inoculated to both C6/36 and BHK21 cells for viral isolation. Positive isolates were identified with arbovirus species-specific primers under RT-PCR, for further sequencing and phylogenetic analysis.</p><p><b>RESULTS</b>A total of 10 455 mosquitoes of 7 species in 4 genuese were collected. The predominant mosquito species in Linyi county was Culex pipens pallens (91.96%, 3 911/4 253), but the one in Yongji city was Culex tritaeniorhynchus (72.85%, 4 518/6 202). A total of 23 strains of viruses were isolated from the mosquito pools. 15 strains from Culex tritaeniorhynchus and Culex pipens pallens were identified as genotype I Japanese encephalitis virus (JEV). Four strains from Culex pipens pallens were identified as Culex flavivirus (CxFV). Three strains from Culex pipens pallens were identified as Culex pipiens pallens densovirus (CppDNV). One strain from Armigeres subalbatus and Aedes albopictus was identified as Getah virus (GETV).</p><p><b>CONCLUSION</b>Four kinds of arboviruses were isolated from the mosquito pools, including GETV and CxFV, which were isolated and documented in Shanxi province for the first time. In the city of Yuncheng, Culex tritaeniorhynchus had been the predominant species and major vector for transmitting JEV. Genotype I JEV remained the major JEV circulating in the local natural environment.</p>

Establishment of TaqMan RT-PCR assay for Flanders virus / 中国人兽共患病学报

The Flanders virus (FLAV) is a number of family Rhabdoviridae ,contains a single‐stranded ,negative‐sense vi‐ral RNA .Here we describe a molecular detection method developed for fast measurement of FLAV based on Taqman RT‐PCR method .In this study ,FLAV specific primers and probe were designed based on the FLAV L gene sequences published in GeneBank .Quantitative standard curve of FLAV TaqMan PCR was also successfully established .The specificity and stability test showed that the system is specific and the coefficient variables were all less than 1 .7% .Quantitative standard curve based on the genomic copy was drawn ,and the lowest detectable limit (LOD) of system was 100 copies/PCR ,with higher sensitivity and stability than that of the conventional RT‐PCR assay targeting the same gene .

Investigation on mosquitoes and mosquito-borne viruses in Dehong prefecture,Yunnan province,2007 and 2010 / 中华流行病学杂志

Objective To investigate the distribution patterns of mosquitoes and mosquito-borne viruses in Dehong prefecture,Yunnan province,China. Methods Mosquito samples were collected using the mosquito traps from five counties of Dehong prefecture on July,2007 and 2010. Mosquitoes were cell cultured for viral isolation,and positive isolates were identified using RT-PCR and sequence analysis. Results A total of 43 634 mosquitoes comprised of 29 species representing six genera were collected. Culex tritaeriorhynchus and Anopheles sinensis comprised 78.69% and 14.77% of the total. Six strains of viruses were isolated from the mosquito pools. RT-PCR and phylogenetic analysis revealed three strains from Cx. tritaeriorhynchus,identified as genotypeⅠJapanese encephalitis virus(JEV). One strain was identified from Cx. tritaeriorhynchus,as Getah virus (GETV). Two strains isolated from Cx. tritaeriorhynchus and Anopheles vagus were identified as Culex pipiens pallens Densovirus(CppDNV). Conclusion Cx. tritaeriorhynchus had been the major species of mosquitoes and mainly transmitting vector of mosquito-borne viruses in Dehong prefecture. GenotypeⅠJEV,GETV and CppDNV were the vectors causing transmission of mosquitoe-borne diseases in this area. Data from phylogenetic analysis showed that these newly discovered isolates seemed to have had close relationship with those viruses previously circulating in Yunnan and other provinces of China.

Investigation on mosquitoes and mosquito-borne viruses in Dehong prefecture,Yunnan province,2007 and 2010 / 中华流行病学杂志

Objective To investigate the distribution patterns of mosquitoes and mosquito-borne viruses in Dehong prefecture,Yunnan province,China. Methods Mosquito samples were collected using the mosquito traps from five counties of Dehong prefecture on July,2007 and 2010. Mosquitoes were cell cultured for viral isolation,and positive isolates were identified using RT-PCR and sequence analysis. Results A total of 43 634 mosquitoes comprised of 29 species representing six genera were collected. Culex tritaeriorhynchus and Anopheles sinensis comprised 78.69% and 14.77% of the total. Six strains of viruses were isolated from the mosquito pools. RT-PCR and phylogenetic analysis revealed three strains from Cx. tritaeriorhynchus,identified as genotypeⅠJapanese encephalitis virus(JEV). One strain was identified from Cx. tritaeriorhynchus,as Getah virus (GETV). Two strains isolated from Cx. tritaeriorhynchus and Anopheles vagus were identified as Culex pipiens pallens Densovirus(CppDNV). Conclusion Cx. tritaeriorhynchus had been the major species of mosquitoes and mainly transmitting vector of mosquito-borne viruses in Dehong prefecture. GenotypeⅠJEV,GETV and CppDNV were the vectors causing transmission of mosquitoe-borne diseases in this area. Data from phylogenetic analysis showed that these newly discovered isolates seemed to have had close relationship with those viruses previously circulating in Yunnan and other provinces of China.

Investigation on mosquitoes and mosquito-borne viruses in Dehong prefecture, Yunnan province, 2007 and 2010 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the distribution patterns of mosquito and mosquito-borne viruses in Dehong prefecture, Yunnan province, China.</p><p><b>METHODS</b>Mosquito samples were collected using the mosquito traps from five counties of Dehong prefecture on July, 2007 and 2010. Mosquito were cell cultured for viral isolation, and positive isolates were identified using RT-PCR and sequence analysis.</p><p><b>RESULTS</b>A total of 43 634 mosquito comprised of 29 species representing six genera were collected. Culex tritaeniorhynchus and Anopheles sinensis comprised 78.69% and 14.77% of the total. Six strains of viruses were isolated from the mosquito pools. RT-PCR and phylogenetic analysis revealed three strains from Cx. tritaeniorhynchus, identified as genotype I Japanese encephalitis virus (JEV). One strain was identified from Cx. tritaeniorhynchus, as Getah virus (GETV). Two strains isolated from Cx. tritaeniorhynchus and Anopheles vagus were identified as Culex pipiens pallens Densovirus (CppDNV).</p><p><b>CONCLUSION</b>Cx. tritaeniorhynchus had been the major species of mosquito and mainly transmitting vector of mosquito-borne viruses in Dehong prefecture. Genotype I JEV, GETV and CppDNV were the vectors causing transmission of mosquito-borne diseases in this area. Data from phylogenetic analysis showed that these newly discovered isolates seemed to have had close relationship with those viruses previously circulating in Yunnan and other provinces of China.</p>

Simultaneous Detection of Three Arboviruses Using a Triplex RT-PCR Enzyme Hybridization Assay / 中国病毒学·英文版

Arboviruses represent a serious problem to public health and agriculture worldwide.Fast,accurate identification of the viral agents of arbovirus-associated disease is essential for epidemiological surveillance and laboratory investigation.We developed a cost-effective,rapid,and highly sensitive one-step triplex RT-PCR enzyme hybridizationassay for simultaneous detections of Japanese Encephallitis virus (JEV,Flaviviridae)Getah virus (GETV,Togaviridae),and Tahyna virus (TAHV,Bunyaviridae) using three pairs of primers to amplify three target sequences in one RT-PCR reaction.The analytical sensitivity of this assay was 1 PFU/mL for JEV,10PFU/mL for GETV,and 10 PFU/mL for TAHV.This assay is significantly more rapid and less expensive than the traditional serological detection and single RT-PCR reaction methods.When “triplex RT-PCR enzyme hybridization” was applied to 29 cerebrospinal fluid(CSF)samples that were JEV-positive by normal RT-PCR assay,all samples were strongly positive for JEV,but negative for GETV and TAHV,demonstrating a good sensitivity,specificity,and performance at CSF specimen detection.