裂谷热诊断技术研究进展

裂谷热(RVF)是由蚊传播的急性、以高热为特征的病毒性传染病,主要感染牛、羊等哺乳动物,也可感染人,被OIE列为A类疫病.虽然我国目前尚未发生RVF的报道,但近年来该病的分布范围有不断扩大的趋势.随着经济全球化的发展,RVF对我国的畜牧业以及人类的健康构成威胁.在国内没有报告RVF病例的情况下,国内对RVF的认识普遍不足,因此需要国境口岸加强对裂谷热进行检测和监测,防止RVF传入是必需的,为加强对裂谷热检测技术的认识,现对裂谷热诊断技术的研究进展进行综述.     

犬瘟热病毒病原学和诊断技术研究进展

犬瘟热病毒（Canine distemper virus, CDV）是引起犬科、鼬科及一部分浣熊科或其它食肉目动物犬瘟热（Canine distemper, CD）的病原[1]。幼龄未免疫动物感染CDV后多表现为急性致死性经过,临床上以双相热型、结膜炎、严重的呼吸系统和消化系统炎症,以及后期出现神经症状为主要特征,成年动物可耐过或呈慢性持续性感染。目前CDV在世界范围内呈广泛性流行,感染宿主的范围不断扩大,多种动物都能感染和传播该病原[2]。     

一例猪流行性腹泻病毒与葡萄球菌混合感染的病原学诊断

为查明贵州省毕节市某猪场仔猪持续腹泻、消瘦死亡的原因,对送检的2头典型发病仔猪进行临床症状和病理剖检观察,采集病料进行细菌分离培养、生化试验、PCR检测和药物敏感性试验,以及猪流行性腹泻病毒、猪传染性胃肠炎病毒、猪轮状病毒RT-PCR核酸检测。结果:仔猪临床症状为精神萎靡,食欲减退,水样腹泻,呕吐,消瘦直至死亡;剖检可见腹股沟淋巴结出血,肠道充气肿胀;细菌分离鉴定为葡萄球菌,该分离菌对盐酸多西环素、硫酸安普霉素、泰乐菌素高度敏感,对磺胺间甲氧嘧啶钠、头孢拉定、替米考星、硫酸粘杆菌素耐药;猪流行性腹泻病毒核酸检测为阳性,猪传染性胃肠炎病毒、猪轮状病毒核酸检测为阴性。结论:该猪场的发病仔猪存在猪流行性腹泻病毒与葡萄球菌混合感染。建议使用高敏药物对葡萄球菌感染进行治疗,同时加强猪流行性腹泻疫苗的免疫。     

非洲裂谷热及其传入我国的风险分析

裂谷热(rift valley fever,RVF),又名里夫特山谷热(该病1930年在非洲肯尼亚里夫特山谷的绵羊中广泛流行),是一种由裂谷热病毒(rift valley fe-ver virus)引起的烈性人畜共患病,通过蚊子叮咬传染人类和牲畜,主要症状是急性腹泻和高热,进而严重损害人和牲畜的肝和肾,部分病人还会因血管破裂而死亡。世界动物卫生组织(OIE)将其纳入多种     

猪伪狂犬病的研究进展

猪伪狂犬病的主要宿主和传染源为猪和鼠.同时可在多种家畜和野生动物之间传染,它一旦感染动物则终生带毒呈潜伏感染状态,给养殖业带来很大经济损失.该病在世界上分布广泛,并有不断蔓延扩大的趋势,各国学者不断对本病进行深入研究.本文就本病的流行病学、病原学、诊断方法、免疫与防制等方面进行综述.1 PR简介与流行现状一般认为本病1818年前后就存在于美国,1902年匈牙利学者Aujesjky首先作了报告,故此得名Aujesjky病(简称AD),随后1910年Schmiedhoffer证明本病是一种病毒病,1931年Shope发现了猪在传播本病上的重要作用,1933年Traud用组织培养方法成功地分离到了病原.     

猪传染性胃肠炎的诊断鉴别和防治方法

猪传染性胃肠炎是由猪传染性胃肠炎病毒引起猪的一种急性肠道传染病。以呕吐、水样腹泻和脱水为特征。各种年龄的猪均可发生,但以10日龄以内仔猪病死率为高。传播迅速,冬季多见。     

猪流行性腹泻的诊断技术及预防策略

1诊断技术1.1免疫电镜法一般来说,电镜法可以有效地做出病原的诊断,可以通过电镜来观察病毒的结构、形态特征及立体构型等特点。如将感染猪小肠或病毒细胞培养物制成超薄切片在电镜下观察,则可从平面上观察到病毒的内部结构,形态大小,复制方式等。由于猪传染性胃肠炎病毒(TGEV)与猪流行性腹泻病毒(PEDV)同属冠状病毒,形状非常相似,在普通电镜下无法区别,为此需要用免疫电镜法(IEM)。IEM法既可用已知     

猪传染性胃肠炎和猪流行性腹泻的鉴别诊断与返饲技术要点

猪传染性胃肠炎病毒(TGEV)与猪流行性腹泻病毒(PEDV)均属于冠状病毒科,两种病毒在65℃条件下10分钟都可灭活,在阳光下6~8小时可灭活,但在阴暗环境中7~10天仍然具有感染力。虽然这是两个独立的疾病,但在流行病学、临床症状和剖检变化等方面都很相似,肉眼鉴别诊断较困难,临床上极易误诊。因为这两种病均无特效治疗药物,近些年一些猪场或养猪户试用古老返饲技术防治该病,疗效还可以。以下简单介绍一下传染性胃肠炎和猪流行性腹泻鉴别诊断与返饲技术要点,供大家参考。     

猪传染性胃肠炎的诊断及防治措施

猪传染性胃肠炎是由冠状病毒科的猪传染性胃肠炎病毒(TGEV)引起的一种急性、高度接触性的肠道传染病,给许多规模化猪场造成了严重的损失。本文将有关的研究进展综述如下。     

猪流行性腹泻病毒分子结构、诊断技术和疫苗的研究进展

<正>猪流行性腹泻病毒属于冠状病毒科冠状病毒属,可以引起猪严重的腹泻与脱水,导致仔猪早期死亡的重要病原之一。该病毒首次在欧洲被发现,随后传播到许多亚洲国家。猪流行性腹泻已成为世界流行性疾病,给养猪业包括疫苗防疫和疫病诊断方面都造成了严重的经济损失。近几年来,随着该病毒分子机制了解的深入,加快了检测手段以及疫苗研制的研究步伐,使得大量有效的新疫苗问世。本文详细分析了猪流行性腹泻病毒分子结构和遗传特性,深入探讨了近期诊断技术和可行性疫苗     

裂谷热的研究新进展

在非洲,裂谷热引起了严重的公共卫生安全和经济危害的问题,并且该病对世界其他国家和地区构成严重的威胁。该病已作为全球优先防范的跨境动物疫病之一,本文从裂谷热的流行病学特点、传播的风险因素、发病机理、诊断技术和疫苗研究等5个方面概述了其最新研究进展,旨在为研究更加有效的方法来防控裂谷热病毒的传播。     

A Rift Valley fever atlas for Africa

Rift Valley fever (RVF) epidemics have serious consequences for human and animal health and the livestock trade. Recent epidemics have occurred in previously unaffected regions, increasing concerns that the geographical range of RVF will continue to expand. We conducted an extensive, systematic review of the literature to obtain serological data for RVF in Africa, collected between 1970 and 2000 from human, livestock and wild ungulate populations. Aims were to calculate sub-national estimates of RVF infection prevalence and to define areas where no information was available. We presented the data (aggregated at the first administrative level of countries) using a geographical information system. Data from 71 publications were used to build a spatially explicit Bayesian logistic-regression model, with spatial and non-spatial random effects, allowing us to identify clusters of high and low RVF seroprevalence, and fixed effects that described the disparate nature of the survey subjects and methods. Significant high-prevalence clusters encompassed areas that had experienced epidemics during the late 20th century and significant low-prevalence clusters were located in contiguous areas of Western and Central Africa.     

Rift Valley fever virus-induced encephalomyelitis and hepatitis in calves.

Three calves (Nos. 1, 2 = 7 days old; No. 3 = 21 days old) were inoculated subcutaneously with virulent Rift Valley fever (RVF) virus. All calves became viremic and clinically ill, but the two 7-day-old calves were moribund and were euthanatized subsequently on post-inoculation day (PID) 3. Highest viral titers were measured in the serum, with lesser concentrations in the brain, heart, spleen, and liver of these animals. Viral antigens were detected by immunohistochemical analysis only in the livers, where positive staining was localized in coalescing foci of hepatocellular necrosis. The 21-day-old calf appeared to recover after viremia and pyrexia but became lethargic and ataxic and was euthanatized on PID 9. The calf was no longer viremic, and RVF virus was isolated only from the brain. Microscopic examination of the central nervous system revealed diffuse perivascular infiltrates of lymphocytes and macrophages, multifocal meningitis, and focal areas of neuronal necrosis and aggregates of macrophages, lymphocytes, and neutrophils throughout all regions of the brain and cervical spinal cord. There was positive immunohistochemical staining for viral antigens within the cytoplasm of neurons and glial cells throughout the central nervous system. Thus, RVF virus can cause encephalomyelitis in calves, and the specific virologic diagnosis can be made by immunohistochemical localization of viral antigens in formalin-fixed tissues.     

Virus-like particle-based countermeasures against Rift Valley fever virus

Rift Valley fever virus (RVFV) is an arbovirus that causes significant morbidity and mortality in both humans and livestock. With increased world travel and the threat of bioterrorism, there is a real risk of RVFV spreading to na?ve geographical areas (Trans. R. Soc. Trop. Med. Hyg., 73, 1979, 618; MMWR Morb. Mortal. Wkly Rep., 49, 2000, 905). The introduction of RVFV would cause critical public health, agricultural and economic damage. Despite the clear need for an efficacious vaccine, there are no United States (US) Food and Drug Administration or US Department of Agriculture approved vaccines against RVFV. To address this need, a virus-like particle (VLP)-based vaccine candidate was developed. First, a non-replicating chimeric RVF VLP vaccine candidate was generated that protected mice and rats against a lethal RVFV challenge. This was followed by the development and optimization of conditions for production of RVF VLPs in insect and mammalian cells. Immunological studies demonstrated that VLP-based vaccine candidates elicit both humoral and cellular immune responses. Subsequent challenge studies using a lethal wild-type RVFV strain under high-containment conditions showed that RVF VLP vaccine candidates can completely protect mice and rats.     

An epizootic of Rift Valley fever in Egypt in 1977

A disease causing increased mortality and abortion in domestic animals during a 1977 epizootic in Egypt was identified as Rift Valley fever (RVF) virus. The epizootic included extensive human involvement reflected clinically as either an acute febrile, ocular, encephalitic, or fatal haemorrhagic form of RVF disease. The virus was again isolated from humans and animals during a second RVF epizootic in the summer of 1978.     

First serological investigation of peste-des-petits-ruminants and Rift Valley fever in Tunisia

This study, carried out between September 2006 and January 2007, is the first cross-sectional serological investigation of peste-des-petits-ruminants (PPR) and Rift Valley fever (RVF) in Tunisia. The objective was to assess the potential need to develop a dual, recombinant PPR–RVF vaccine and how such a vaccine might be utilised in Tunisia. An overall PPR seroprevalence of 7.45% was determined, a finding supported by the high specificity (99.4%) and sensitivity (94.5%) of the ELISA used. On assessment of the diversity and density of mosquitoes in the sampling area, four species of RVF-vectors of the genus Aedes and Culex were identified. However, no serological evidence of RVF was found despite the use of a highly sensitive ELISA (99–100%). Larger scale investigations are underway to confirm these findings and the continuation of the emergency vaccination program against these two diseases remains valid.