伯氏疏螺旋体鞭毛基因的克隆及序列分析

根据已有的伯氏疏螺旋体鞭毛基因序列,设计两条特异性引物,PCR扩增该基因,并获得基因全长序列,大小为1 008 bp。采用生物信息学技术,对所获得的伯氏疏螺旋体鞭毛基因序列和拟编码的蛋白序列进行分析,发现其编码336个氨基酸,编码蛋白的理论分子量为35.7 ku,等电点为5.53,具有多个抗原表位序列,其中编码主要抗原位点的片段位于中央区段,该中央区段还具有伯氏疏螺旋体种的保守性。伯氏疏螺旋体鞭毛基因中央区段编码蛋白既是主要的抗原位点又具有保守性,理论上可作为莱姆病的诊断抗原。本文为莱姆病的实验室诊断奠定基础。     

伯氏疏螺旋体鞭毛基因的PCR单链构象多态性分析

应用多聚酶链反应单链构象多态性（ＰＣＲ－ＳＳＣＰ）技术分析了甘肃地区伯氏疏螺旋体和国际标准株Ｂ３１的鞭毛基因,发现甘肃不同宿主的２株伯氏疏螺旋体的鞭毛基因是一致的,属间一型螺旋体,而与Ｂ３１株明显不同,证明甘肃地区分离株与Ｂ３１株在鞭毛基因上不属同一型螺旋体。     

牡丹江野生鹿血中伯氏疏螺旋体分子检测

为了解牡丹江地区野生鹿自然感染伯氏疏螺旋体的情况,2019年6月间在牡丹江海林市采集20份野生鹿血标本,应用普通PCR对鹿血标本进行5S-23S基因片段的扩增和测序,并将所得序列与GenBank中的项序列进行分析.结果检出7份阳性样本,阳性率为35％,序列分析发现伯氏疏螺旋体在有2个基因型,分别是Borreliella...     

广东从化无规定马属动物疫病区野鸟和蚊子分布及其西尼罗病毒感染情况调查

[目的]了解广东从化无规定马属动物疫病区野鸟和蚊子的种类、数量和分布等情况及其西尼罗病毒感染的情况。[方法]对鸟类在沿途设网抓捕取样;蚊虫采用紫外灯诱捕和网捕进行样品采集,随后利用荧光定量RT-PCR方法对西尼罗病毒进行检测。[结果]2012—2013年该地区共捕获鸟类110种381只,隶属于12目37科76属;共捕获蚊虫5种,共计3048只,其中淡色库蚊占50.66%、三带喙库蚊占32.12%、褐尾库蚊占12.99%、中华按蚊占3.61%和白纹伊蚊0.62%;对381份鸟泄殖腔棉拭子和3048份蚊子样品进行了西尼罗病毒的检测,结果均为阴性。[结论]虽然本次调查未发现鸟类及蚊子感染西尼罗病毒,但本地区存在西尼罗病毒引入以及在本地区传播的条件,存在西尼罗病毒病发生风险。因此,为继续维持广东从化无规定马属动物疫病区的无疫状态,有必要对媒介鸟类及蚊虫开展长期的调查和监测。     

上海地区规模化猪场牛病毒性腹泻病毒感染状况的血清学调查

为调查猪瘟疫苗是否会引起牛病毒性腹泻的发生及上海地区规模化猪场该病的流行情况,本试验采用酶联免疫吸附试验方法,对分别免疫接种3种猪瘟疫苗的57头试验猪以及上海地区2005年-2009年10个区(县)共740份血清进行了牛病毒性腹泻病毒抗原和抗体的检测.经检测,所有样品抗原和抗体均为阴性.结果表明,免疫猪瘟脾淋苗不能使猪产生BVDV交叉抗体,猪群因猪瘟疫苗感染BVDV的可能性比较低,该病近几年在上海市猪群中并没有出现.     

上海地区规模化猪场牛病毒性腹泻病毒感染状况的血清学调查

为调查猪瘟疫苗是否会引起牛病毒性腹泻的发生及上海地区规模化猪场该病的流行情况,本试验采用酶联免疫吸附试验方法,对分别免疫接种3种猪瘟疫苗的57头试验猪以及上海地区2005年-2009年10个区(县)共740份血清进行了牛病毒性腹泻病毒(BVDV)抗原和抗体的检测.经检测,所有样品抗原和抗体均为阴性.结果表明,免疫猪瘟脾...     

伯氏疏螺旋体TaqMan-MGB探针荧光定量PCR方法的建立及对新疆地区蜱的检测

为建立一种TaqMan-MGB探针实时荧光定量PCR方法,来快速、特异地检测伯氏疏螺旋体,根据GenBank发表的伯氏疏螺旋体16SrRNA序列,应用分子生物学软件进行比对,选取保守序列设计特异性引物及TaqMan-MGB探针,并优化荧光定量PCR反应体系及条件,分别对大肠杆菌、沙门氏菌及钩端螺旋体进行扩增;构建伯氏疏螺旋体标准株16SrRNA基因片段阳性质粒,10倍系列稀释后进行real-time PCR扩增,测定该方法的敏感性。结果可见:仅伯氏疏螺旋体出现阳性扩增,而大肠杆菌、沙门氏菌及钩端螺旋体扩增均为阴性;该方法对阳性质粒的检测限约为100 copies/μL。应用该方法对新疆地区的100份蜱DNA样本进行检测,发现7份为伯氏疏螺旋体阳性。结果表明,本研究建立的TaqMan-MGB探针荧光定量PCR方法具有较高的特异性及良好的敏感性,为今后伯氏疏螺旋体的快速诊断及流行病学调查提供了技术支撑。     

上海地区奶牛场牛病毒性腹泻-黏膜病的血清学调查

牛病毒性腹泻一黏膜病是牛最重要的传染病之一,给全球的奶牛业造成了严重的经济损失.为了调查上海地区奶牛场该病的流行情况,通过对2009年1月～4月份采集的上海10个区(县)18个规模化奶牛场成年乳牛和育成牛共180份血清以及奉贤区25份犊牛血清进行了病原和抗体的酶联免疫吸附试验检测.结果表明,上海地区奶牛场205份血清中...     

新疆北疆部分地区鼠类伯氏疏螺旋体携带情况调查

为了解新疆北疆地区鼠类伯氏疏螺旋体携带情况及其基因型分布特征,2021年1—9月在新疆昌吉州吉木萨尔县、伊犁哈萨克自治州新源县、塔城地区乌苏市巴音沟,采集147只野生鼠类的肾脏和膀胱组织样本,采用实时荧光定量PCR和巢式PCR方法,检测鼠类中的伯氏疏螺旋体携带情况;以伯氏疏螺旋体5S—23S基因间隔区进行巢式 PCR检测,对检出的阳性样本进行基因测序及序列分析,确定伯氏疏螺旋体基因型,构建系统发育树。结果显示：在147份鼠类样本中,经实时荧光定量PCR和巢式PCR方法检测,分别检出伯氏疏螺旋体阳性样本11份和13份,阳性率分别为7.48%和8.84%;13份巢式PCR阳性样本中,吉木萨尔县检出1份,新源县检出1份,乌苏市检出11份,通过序列同源性分析确定Borreliella garinii、Borreliella bavariensis为主要致病基因型。结果表明,北疆地区鼠类中存在伯氏疏螺旋体的自然感染,有传播给家畜及人群的风险,应加强该病原体检测和莱姆病防控。     

规模化猪场脑心肌炎病毒感染的血清学调查

脑心肌炎病毒(EMCV)可引起猪的脑炎、心肌炎和母猪繁殖障碍,该病已在世界上多个国家暴发和流行。我国对EMCV及其所致疾病的研究工作还处于起步阶段,为了揭示EMCV在我国规模化猪场的感染情况,我们应用酶联免疫吸附试验(ELISA)对2005-2006年间采集自全国13个省市46个规模化猪场的3250份血清样本进行了EMCV抗体检测,结果显示,各省阳性率在39.64%~90%之间,平均抗体阳性率为72%,监测的46个猪场都存在EMCV感染,猪场感染阳性率为100%;对不同生长阶段猪群检测结果表明,EMCV抗体阳性率随猪龄的增长而升高,且不同生长阶段猪抗体阳性率差异极显著;成年公猪的抗体阳性率高于成年母猪。本项调查表明,我国规模化猪场已经普遍感染EMCV,这应引起我国养猪业警惕,并做好该病的综合防控。     

西尼罗河病毒病的研究进展

西尼罗河病毒病是由西尼罗河病毒(West Nile Virus,WNV)引起的一种人畜共患传染病,病原是一种虫媒病毒,可导致西尼罗河热和致死性的西尼罗河脑炎。自发现以来,西尼罗河病毒病曾在世界上多个国家暴发,给畜牧业和人类生命安全造成了巨大的危害。我国目前尚无该病的发生,但是防治技术储备是必要的。本文对西尼罗河病毒病的流行病学、病原学、致病机制、临床症状和病理剖检变化、诊断方法和候选疗法进行综述,为西尼罗河病毒病的防控提供资料。     

First serological evidence of West Nile virus infection in wild birds in Northern Algeria

While the epidemiology of Flaviviruses has been extensively studied in most of the Mediterranean basin, little is known about the current situation in Algeria. In order to detect the circulation of West Nile (WNV) and Usutu viruses (USUV) in Kabylia, 165 sera were collected from two wild birds species, namely the long distance migrant Turdus philomelos (song thrush) (n = 92) and the resident Passer domesticus (house sparrow) (n = 73). A total of 154 sera were first analyzed by commercial competition ELISA. WNV and USUV micro-neutralization tests were performed on all c-ELISA positive sera and all samples with poor volume. Overall, 7.8 % (CI95 %: 3.5–11.9) were positive by c-ELISA. Positive results were detected in 12.5 % (CI95 %:5.6–19.4) of song thrushes and 1.5 % (CI95 %: 0.0–4.5) for sparrow.Micro-neutralization tests revealed an overall seroprevalence of 6.7 % for WNV (CI95 %: 2.9–10.3), Neutralizing antibodies were found in 8.7 % (CI95 %: 3.0–14.4) for song thrushes and in 4.1 % (CI95 %: 0.0–8.7) of sparrows. The current study demonstrates significant seroprevalence of WNV antibodies in wild birds in Algeria.     

West Nile virus: North American experience

West Nile virus, a mosquito‐vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito‐transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito‐borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.     

新疆地区蚊类携带西尼罗病毒情况调查研究

为查明新疆地区蚊体内携带西尼罗病毒的情况,从2005年-2007年每年的7月~10月采集新疆不同地区的蚊子共计16000余只,并提取总RNA,通过RT-nest PCR的方法检测样品中西尼罗病毒。结果表明,调查样品中没有检测到西尼罗病毒,但不能就此推测新疆是否存在西尼罗病毒,至少对新疆地区和全国制定针对不同动物和人的积极防御政策有重要的公共卫生学意义。     

Serologic evidence of West Nile virus and Usutu virus infections in Eurasian coots in the Netherlands

West Nile virus (WNV) and Usutu virus (USUV) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. As arboviruses are currently expanding their geographic range and emerging in often unpredictable locations, surveillance is considered an important element of preparedness. To determine whether sera collected from resident and migratory birds in the Netherlands as part of avian influenza surveillance would also represent an effective source for proactive arbovirus surveillance, a random selection of such sera was screened for WNV antibodies using a commercial ELISA. In addition, sera of jackdaws and carrion crows captured for previous experimental infection studies were added to the selection. Of the 265 screened serum samples, 27 were found to be WNV–antibody‐positive, and subsequent cross‐neutralization experiments using WNV and USUV confirmed that five serum samples were positive for only WNV‐neutralizing antibodies and seven for only USUV. The positive birds consisted of four Eurasian coots (Fulica atra) and one carrion crow (Corvus corone) for WNV, of which the latter may suggest local presence of the virus, and only Eurasian coots for USUV. As a result, the screening of a small selection of serum samples originally collected for avian influenza surveillance demonstrated a seroprevalence of 1.6% for WNV and 2.8% for USUV, suggesting that this sustained infrastructure could serve as a useful source for future surveillance of arboviruses such as WNV and USUV in the Netherlands.     

Serological evidence of West Nile virus infection in human populations and domestic birds in the Northwest of Morocco

West Nile virus (WNV) was recently detected in Culex pipiens mosquitoes in Morocco. The aim of this study was to evaluate the seroprevalence of WNV in humans and in domestic birds in two regions of Morocco by the detection of IgG antibodies. Blood samples were obtained from 91 human patients and 92 domestic birds from September to December 2019. All study samples were tested using competitive enzyme-linked immunosorbent assay (cELISA) and WNV neutralization tests (VNT) were performed on positive sera. Of all samples, 4 (4.39 %) humans and 4 (4.34 %) birds were found to be seropositive for flaviviruses by the cELISA test. The VNT revealed that three of the four human samples detected positive by cELISA contained neutralizing antibodies against WNV. Two bird samples were confirmed positive by VNT. These results show a significant seroprevalence of anti-WNV antibodies and therefore suggest the active circulation and exposure of human and bird populations in the northwest of Morocco.     

West Nile virus infection in horses,Indian ocean

The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4–55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries.     

西尼罗河病毒病竞争ELISA检测方法的初步建立及应用

本研究用表达的西尼罗河病毒(WNV)囊膜蛋白E结构域III蛋白作为包被抗原,单抗8F4A4作为竞争检测抗体,初步建立了能够对乙型脑炎病毒(JEV)和WNV进行鉴别诊断的竞争ELISA方法。优化的最佳抗原包被浓度为530ng/mL,单抗的最佳稀释倍数为1:8000,待检血清的最佳稀释倍数为1:10。通过对56份阴性样品进行检测确定了该方法的临界值为30%,以此为判定标准对临床220份血清进行检测,结果均为阴性。此方法的建立弥补了商品化试剂盒不能区分JEV和WNV感染的缺陷,为我国西尼罗河病毒病的流行病学调查提供了一种有效的抗体检测方法。     

West Nile Virus Transmission in 2008 in North‐Eastern Italy

After 10 years, West Nile virus (WNV) re‐emerged in Italy in August 2008. As on 31 December 2008, the infection affected eight Provinces in three Regions (Emilia Romagna, Veneto, Lombardy), where a total of 794 cases of WNV infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. Only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in 18 different farms. The observed case‐fatality rate was 15.6% (5/32). The confirmed clinical cases were detected from end August to mid October. Significant levels of positivity by RT‐PCR were also observed in magpies (Pica pica) (9.1%, 95% confidence levels: 6.1–13.4%), carrion crows (Corvus corone) (7.4%, 95% confidence levels: 3.6–14.4%) and rock pigeons (Columba livia) (12.9%, 95% confidence levels: 7.6–21.2%).