埃及伊蚊传播西尼罗病毒的媒介效能研究

目的研究我国埃及伊蚊传播西尼罗病毒的潜在能力。方法人工配制病毒血餐感染埃及伊蚊并进行传播实验,应用反转录聚合酶链反应（RT？PCR）、病毒分离和间接免疫荧光法（IFA）检测蚊虫和来亨鸡体内病毒。结果动物实验结果表明敏感动物来亨鸡感染西尼罗病毒后,第2天其体内病毒量达到最高,说明进行传播实验后的第2天是检测传播是否成功的最佳时间。感染与传播实验结果表明埃及伊蚊对西尼罗病毒的感染率达到了63.3%,而且通过刺叮敏感动物（来亨鸡）能够传播该病毒,其传播率为30.0%。结论在未来我国可能的西尼罗热暴发中,埃及伊蚊可能成为其在海南等地的潜在传播媒介。     

用空斑技术测定口服脊髓灰质炎三价疫苗的效价

目前 ,测定脊髓灰质炎疫苗 (OPV)的效价多采用微量细胞病变法。其实脊髓灰质炎三价糖丸疫苗是一种活疫苗 ,象其它引起细胞病变的病毒一样 ,在某些培养的单层细胞中能形成肉眼可见的空斑。测定空斑形成的数量可准确地了解病毒的感染性 ,获得比 5 0 %细胞培养感染滴度 (TCID5 0 )更精确的结果。空斑技术首先是由 Dulbecco在 195 2年发明的〔1〕。经典的空斑试验包括在接种病毒的单层细胞上覆盖琼脂营养液 ,用中性红染色。该研究用甲基纤维素营养液覆盖接种病毒的单层细胞 ,在实验完后用结晶紫染色就可见明显的空斑 ,获得了满意的结果。1　…     

天津市蚊虫西尼罗病毒携带调查

目的了解天津市蚊虫携带西尼罗病毒（WNV）情况。方法以灯诱法进行蚊虫采集,采用荧光定量PCR检测方法对WNV进行检测。结果天津市有候鸟栖息的湖泊、洼地周边主要蚊种为淡色库蚊（占93．68％）,同时存在凶小库蚊和三带喙库蚊。对1091只蚊虫进行西尼罗病毒检测,结果均为阴性。结论本次调查未发现蚊虫携带WNV,为预防和控制WNV传人及可能发生的流行,有必要开展对媒介蚊虫及WNV的长期监测。     

空斑减少中和试验测定血清抗乙脑病毒抗体

目的：对比空斑减少中和试验与反向被动血凝抑制试验在评价人血清抗乙脑病毒抗体时间定结果的异同。方法：对450名6－10岁儿童接种灭活乙脑疫苗前后的血清样本用两种方法进行了测定。结果：两种方法在测定免前人血清抗乙脑病毒抗体时存在显性差异，在测定免后人血清抗乙脑病毒抗体时两没有差异。结论：空斑减少中和试验比反向被动血凝抑制试验在测定人血清抗乙脑病毒抗性时灵敏。     

SYBR GreenⅠ荧光定量PCR检测西尼罗病毒

目的建立快速、敏感和特异的检测西尼罗病毒的SYBRGreenⅠ荧光定量PCR法，用于西尼罗病毒（WNV）疾病的早期诊断。方法采用RT—PCR扩增WNV基因片段，将其克隆至T载体，重组质粒测序并进行同源性分析；阳性质粒用于替代WNV，以阳性质粒为模板，建立SYBRGreenⅠ荧光定量PCR检测方法，并进行敏感性和特异性检测。结果经测序证实扩增片段属于WNV，所建立的SYBRGreenⅠ荧光定量PCR法可检测到10拷贝的西尼罗病毒RNA，而对其他黄病毒科成员日本脑炎病毒及登革热病毒的检测则为阴性，表明该方法特异。结论SYBRGreenⅠ荧光定量PCR简便快速，具有较高的敏感性和特异性，可以成为一种早期检测西尼罗病毒的新方法。     

近年来西尼罗热的流行现状及其流行毒株的表型和基因型特性

西尼罗热(West Nile Fever，WNF)是由西尼罗病毒(West Nile Virus，WNV)通过蚊虫传播感染引起的一种急性传染病。WNV于1937年在乌干达西尼罗地区的一位发热妇女的血液首次分离到，为黄病毒属日本脑炎(乙脑)病毒抗原复合组内成员。该组成员包括在亚洲广泛流行的日本脑炎病毒，在美国流行的圣路易脑炎病毒，在澳洲流行的Kunjin和墨立谷脑炎病毒，成员间抗原性关系密切，基因同源性高达70％以上，相互间有较高的交互中和保护作用。     

西尼罗病毒输血传播和献血者筛检

2002年．西尼罗病毒(WNV)可以通过输血途径传播(TAT)已得到证实。虽然蚊虫叮咬仍然是西尼罗病毒的主要传播途径,但也说明了西尼罗病毒在输血方面的筛检工作还做得不够。本文主要阐述2003年美国血液采集机构(BCAs)运用核酸扩增技术(NATs)对西尼罗病毒血样筛检的结果及发现6例输血感染者。结果表明通过对献血者的血样进行西尼罗病毒的筛检可以大大提高输血的安全性。     

病毒性脑炎患者外周血和脑脊液西尼罗病毒E基因的检测

西尼罗病毒(WNV)是单股正链RNA病毒,属于黄病毒科黄病毒属,其传播媒介和储存宿主是蚊虫[1].人感染WNV会出现感冒样症状,部分患者为脑膜脑炎、坏死性脑干炎等神经系统症状[2,3].本研究对重庆地区不明病因的78例病毒性脑炎(VE)患者血液和脑脊液进行wNV E基因片段检测.     

登革2型病毒疫苗在恒河猴体的病毒血症与免疫反应

用印度恒河猴作登革2型病毒疫苗试验研究,以检测疫苗安全性、效果、免疫反应和蚊细胞病毒感染小空斑、对温度敏感的变异性。从登革2型病毒的变异来筛选疫苗。用15只猴子作疫苗病毒接种,其中10只猴子接种10~(3.1)空斑形成单位(PFU)疫苗量,另5只猴子接种10~(4.5)空斑形成单位的疫苗量。初次免疫接种后,只有1只接受高剂量的猴子检测出有病     

流行性乙型脑炎病毒在恒河猴肾传代细胞上的蚀斑技术研究及其应用

流行性乙型脑炎(以下简称乙脑)病毒在原代鸡胚细胞和原代地鼠肾细胞上可以形成空斑。但因原代细胞来源比较困难,制备适合空斑形成的致密单层细胞难度较大,形成的蚀斑维持时间短。所以乙脑空斑技术在我国基层尚未普遍推广应用,本文试图应用恒河猴肾传代细胞(LLC—Mk_2)进行乙脑病毒空斑试验,应用于乙脑病毒株生物学特性的研究和微量抗体测定。材料与方法(一) 病毒选乙脑强毒P_3株、A_2株、SA_(14)株和SA_(14-2)弱毒株进行试验观察。强毒株系在小鼠脑内传代的鼠脑病毒。试验时将受染鼠脑     

Search for epizootic-like Venezuelan encephalitis virus at enzootic habitats in Guatemala during 1969-1971.

Seventy-four strains of Venezuelan encephalitis (VE) virus recovered from sentinel hamsters or mosquitoes at enzootic habitats in Guatemala in the two years following the 1969 epidemic-equine epizootic were examined for ability to produce small plaques in Vero African green monkey kidney cell cultures, like isolates obtained during the epizootic. (a) One strain recovered from a sentinel hamster in late October 1969 at an enzootic habitat near the epicenter of the hemagglutination-inhibition (HI) and equine-virulence properties like epizootic virus; this strain retained its small plaque characteristic after inoculation and recovery from bloods of three horses. (b) None of the other 73 strains produced uniformly small plaques, but 31 formed a few small plaques among large ones. Virions from small plaques of five strains were cloned twice in Vero cell cultures. Four clones produced uniformly small plaques after one more passage in Vero cells; three had hemagglutination-pH properties compatible with epizootic virus or intermediate between epizootic and enzootic virus, but HI tests with these three hemagglutinins or with antibody to the fourth cloned strain showed them to be like Central American enzootic virus. One of three cloned strains tested in horses produced encephalitis and death in one of four horses; another strain produced encephalitis with recovery in one of two horses. (c) Thus these small Vero plaque clones resembled Central American enzootic strains of VE virus in HI and equine-virulence tests, and the small Vero plaque characteristic was not a satisfactory marker for consistently isolating equine-virulent, epizootic VE virions. Nevertheless, this technic led to recognition of one epizootic strain isolated at an enzootic habitat in Guatemala at the end of 1969 outbreak. Whether this strain was there before the outbreak or subsequently penetrated the habitat is uncertain. During the next two years, this strain did not become dominant in that enzootic focus.     

Experimental infection of horses with West Nile virus

A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 isolates. Postinfection, uninfected female Ae. albopictus fed on eight of the infected horses. In the first trial, Nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 to 4, respectively. In the second trial, the seven horses with subclinical infections developed Nt antibody titers >1:10 between days 7 and 11 post infection. The highest viremia level in horses fed upon by the recipient mosquitoes was approximately 460 Vero cell PFU/mL. All mosquitoes that fed upon viremic horses were negative for the virus. Horses infected with the NY99 strain of WNV develop low viremia levels of short duration; therefore, infected horses are unlikely to serve as important amplifying hosts for WNV in nature.     

A flow cytometric granularity assay for the quantification of infectious virus

A flow cytometry-based assay was developed to assess the infective titer of two recombinant viruses: a recombinant herpes simplex type 2 (rHSV-2) and a recombinant canary pox (rALVAC.gfp). This method uses granularity of infected Vero and QT-35 cells, respectively, and correlates this to the infectious titer of virus samples. The percent of the cell populations with a high level of granularity could accurately be correlated to viral titers obtained through a traditional plaque assay, with R² values greater than 0.8 using a semi-logarithmic scale. This approach offers a rapid, high-throughput method for infectious virus titration with similar accuracy to a traditional plaque assay.     

Estimation of the infectivity of herpes simplex virus type I passage III on two different tissue culture.

This technique has been developed for the estimation of the infectivity of herpes simplex virus type I passage III on a tissue culture of Vero and HBK21. The plaque assay method was performed and the number of plaques on the two culture media was counted per each dilution from (10(-5) to 10(-8)). It was found that the number and the size of plaques in 10(-5) dilution are the best in the two types of tissue cultures. The number indicates the number of virus particle (per each dilution point), which can be used for infection of experimental animals to demonstrate its infectivity character.