Detection of avian encephalomyelitis virus

Methods for the detection of two strains of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures and chickens were compared. It was found that the agar gel precipitin test (AGPT) and the enzyme-linked immunosorbent assay (ELISA) carried out on the serum of inoculated chickens were more sensitive than either the indirect fluorescent antibody test in cell cultures or the detection of clinical signs in chicks. On the basis of results obtained in this experiment the effects were then determined of routes and time of inoculation of chickens on the detection of AEV. It was found that birds infected at two weeks old produced higher antibody titres than one-day-old birds and the AGPT and ELISA detected comparable levels of antibody in them. It was recommended that the tests to detect the presence of AEV as a contaminant of vaccines be replaced by a serological test carried out on chicks inoculated intramuscularly at two weeks old.     

禽脑脊髓炎病毒单克隆抗体制备

禽脑脊髓炎病毒（ＡＥＶ）在患鸡体内含量很低,且细胞培养的复制水平也很低,故对该病毒的研究一直不够深入,国外有关ＡＥＶ单克隆抗体的报告首见于１９９４年［１］。本研究制备了３株抗ＡＥＶ单克隆抗体,为ＡＥＶ的实验室诊断提供了一种简单、快速、可靠的方法,同时...     

应用原位杂交检测禽脑脊髓炎病毒

禽脑脊髓炎病毒(AEV)是属于小RNA病毒科、肠病毒属的一种正链RNA病毒，病毒粒子具有六边形轮廓，无囊膜，大小为22～25nm，病毒基因组全长为7055nt，具有PloyA尾，它主要侵害幼鸡中枢神经系统，从而引起以非化脓性脑炎为主要病理特征的一种病毒性传染病。由于AEV致病性     

利用鸡胚成纤维细胞培养禽脑脊髓炎病毒的研究

利用鸡胚成纤维细胞 (CEF)培养禽脑脊髓炎病毒 (AEV) ,经过六次盲传发现 :AEV在 CEF上无细胞病变 (CPE) ,但利用 CEF细胞上清接种 SPF鸡胚 ,可产生不同程度的 AE鸡胚病变。分别取不同时间的感染细胞上清 ,测定 AEV浓度 ,结合培养条件 ,进而确定 AEV培养的最佳时机。结果表明 :以 AEV在 CEF上培养 7天最好 ,病毒滴度可达 10 2 .8EID50 / 0 .2 ml。将经 CEF培养的 AEV差速离心 (浓缩约 5 0 0倍 ) ,接种 SPF鸡胚 ,可产生典型的鸡胚病变 ,其滴度为 8× 10 5.0 EID50 / 0 .2 m l。通过 Cs Cl密度梯度离心提纯病毒 ,在电镜下观察到了大小基本一致的病毒粒子 ,病毒直径约为 2 5 nm。利用 AEV感染的 CEF或通过“细胞飞片”制备荧光片 ,建立了间接免疫荧光快速检验 CEF是否感染 AEV的方法。     

抗禽脑脊髓炎病毒单克隆抗体的研究——禽脑脊髓炎病毒抗原的培养和纯化

为获得用于制备AEV单克隆抗体的抗原，将禽脑脊髓炎病毒（AEV VR）接种于鸡胚成纤维细胞（CEF）盲传，通过间接免疫荧光试验（IFA）监测AEV增殖情况，以第六代CEF培养物作为种毒扩大培养，将其培养物经差速率心后的半提纯物接种6日龄SPF鸡胚、1日龄SPF鸡，再将半提纯物经密度梯度离心后进行PAGE－SDS电泳，电镜观察。结果证实，AEV VR在CEF上增殖成功。     

Antibody responses of naive cattle to two inactivated bovine viral diarrhoea virus vaccines,measured by indirect and blocking ELISAS and virus neutralisation

Two groups of naive heifers were given primary courses of two inactivated bovine viral diarrhoea (BVD) virus vaccines licensed for use in the UK. Their humoral responses in serum and milk were assayed by means of an indirect ELISA detecting antibodies to structural viral glycoproteins, a blocking ELISA specific for antibodies to the non-structural protein NS2-3 and the virus neutralisation test (VNT). For each assay, the numbers of serum or milk samples testing positive at each sample point and the mean values were determined. In both vaccine groups, serum antibody responses were detected by the indirect ELISA and the VNT, with both the numbers of seropositive animals and mean values peaking five weeks after the second vaccination. In the 23 heifers vaccinated with Bovilis BVD, the mean NS2-3-specific ELISA values remained low throughout the trial, with no serum or milk samples testing positive. In the 24 heifers vaccinated with Bovidec, the mean NS2-3 responses peaked below the level of positivity five weeks after the second vaccination, before declining again; NS2-3-specific antibodies were detected in one serum sample and one milk sample from two heifers in this group. A pooled milk sample from each vaccine group tested negative by both ELISAS 12 weeks after the second vaccination.     

Physico-chemical and morphological characteristics of avian encephalomyelitis virus

Avian encephalomyelitis virus (AEV) was purified from infected chick embryos by a gradient centrifugation in cesium chloride. The virus had a buoyant density of 1.31 to 1.32 g/ml and a sedimentation coefficient of 148 S. The purified AEV was resistant to treatments with chloroform, acid pH or trypsin. The presence of Mg⁺⁺ stabilized the virus against heat inactivation (56°C, 1 h). Electron microscopic study showed the virus to be 24 to 32 nm in diameter. The surface structure of the purified virus was not easily discernable. Nevertheless, with uranyl acetate-stained particles, Markham's rotation technique revealed that AEV has five-fold symmetry with 32 or 42 capsomers. Exact classification of AEV awaits characterization of the viral nucleic acid.     

Pancreas-passaged avian encephalomyelitis virus and its immunogenicity.

A serial 34-chicken pancreas passage of avian encephalomyelitis virus by oral administration was successful. Oral inoculation test with 4 passaged viruses showed rapid infection of the duodenal wall and unchangeable infection of pancreas diminishing the viral invasiveness to other organs. The passaged virus caused neither detectable viremia nor clinical avian encephalomyelitis signs and produced neutralizing antibody of high titers.     

禽脑脊髓炎病毒单克隆抗体的制备与初步应用

利用提纯的禽脑脊髓炎病毒（AEV）Van Roekel株作为免疫原，免疫6周龄BALB／c小鼠，采取其脾细胞与SP2／0骨髓瘤细胞融合，用间接ELISA法筛选，间接免疫荧光法（IFA）和免疫组织化学法鉴定，经3次亚克隆得到了稳定分泌抗AEV单克隆抗体的杂交瘤细胞株F11和G2，制备了腹水，并利用该单克隆抗体初步建立了Dot—ELISA、间接ELISA和IFA等特异性检测AEV抗原的方法。     

Antigenic relatedness of pigeon herpes encephalomyelitis virus to other avian herpesviruses

Pigeon herpes encephalomyelitis virus (PHEV) was compared with seven avian herpesviruses for antigenic relatedness using monospecific antisera and the indirect fluorescent-antibody (IFA), agar-gel-immunodiffusion, and serum-neutralization tests. No antigenic relationship was detected between PHEV and Marek's disease virus, turkey herpesvirus, infectious laryngotracheitis virus, and duck enteritis virus. A common precipitating antigen was detected between the PHEV and pigeon herpesvirus (PHV), owl herpesvirus (OHV), and falcon herpesvirus (FHV). These four viruses also cross-reacted in the IFA test. Weak neutralizing activity was detected only between PHV antiserum and PHEV. These results suggest that the PHEV should be classified as a herpesvirus related to, but distinct from, the PHV-OHV-FHV group of viruses with which it shares common antigens.     

Antibody response to Newcastle disease virus given by two different routes as measured by ELISA and hemagglutination-inhibition test and associated tracheal immunity

The enzyme-linked immunosorbent assay (ELISA) and the conventional hemagglutination-inhibition (HI) test were compared for their ability to measure the primary serological response of chickens inoculated by the intranasal-intraocular (IN-IO) routes with Newcastle disease virus (NDV) and the secondary response after intratracheal (IT) challenge. In addition, these responses were compared with the temporal antibody response of chickens inoculated only once by the IT route. Both tests detected NDV-specific antibody by 7 days postinoculation (PI) in the IN-IO-inoculated group, while ELISA and the HI test detected antibody at 4 and 7 days, respectively, in the IT-inoculated group. Titers measured by each test were parallel in quantifying the antibody response, and titers rose anamnestically in response to secondary IT challenge at 21 days PI. ELISA titers remained high at 42 days PI, but the HI titers began to decline at this time. There was a good agreement (R = 0.94) between the results of the two tests throughout both primary and secondary responses. Conversely, there was little agreement between the results of the two tests after 21 days PI in the absence of secondary challenge. Antibody levels were higher when inoculation was by the primary IT route, and they persisted throughout the experiment (86 days). Ciliary activity served as a measure of tracheal immunity or infection of tracheal epithelium. It was reduced as early as 2 days PI and was nearly or completely absent by 5-6 days PI.(ABSTRACT TRUNCATED AT 250 WORDS)     

禽脑脊髓炎病毒感染雏鸡的病理组织学观察

禽脑脊髓炎(AE)是由禽脑脊髓炎病毒(AEV)以主要侵害幼鸡中枢神经系统引起非化脓性脑脊髓炎为主要病理特征的急性、高度接触性传染病[1].成年母鸡主要表现为产蛋量有不同程度的下降,雏鸡死亡率可高达57%[2-3].部分存活鸡一侧或两侧眼球的晶状体混浊或呈浅蓝色,严重者失明[4].     

The effect of tiamulin administered by different routes and at different ages to turkeys receiving monensin in their feed

Healthy turkeys receiving 80 ppm monensin in their feed were injected at 26, 40 and 61 days of age with tiamulin at dosages of 12.5 and 25 mg/kg body weight. The aim of the study was to develop a regime for medicating with tiamulin turkeys receiving monensin in their feed, and which would circumvent the known toxicity created by the simultaneous administration of the two drugs. One injection of 12.5 mg/kg tiamulin up to the age of 61 days or 2 injections of 12.5 mg/kg tiamulin up to 40 days of age caused no mortality or adverse reaction.