Detection and differentiation of strains of Newcastle Disease Virus by complement fixation.

A complement-fixation test to detect Newcastle disease virus with antiserum produced in guinea pigs is described. Methodology is given for serum production and for standardization of the test. The test was used to differentiate 13 strains of Newcastle disease virus. Velogenic strains, including isolants form 1970-71 disease outbreaks in California, Florida, and Texas, were poor complement-fixing antigens, whereas lentogenic strains, including LaSota, Hitchner, and England F, were strong complement-fixing antigens. Mesogenic strains ranged from weak to strong in complement-fixing capabilities. This test can be used to differentiate velogenic field isolants from vaccine strains such as LaSota, Hitchner, and Roakin.     

Isolation of Parainfluenza type 3 virus from sheep in New Zealand

Extract

Bovine virus diarrhoea (BVD) and infectious bovine rhinotracheitis (IBR) viruses are commonly thought on clinical grounds to be widespread in the. New Zealand cattle population, and records of virus isolation and serology from this laboratory support this assumption. To date, however, few reports have been published on the prevalence of these two diseases in New Zealand.     

牛副流感病毒3型检测方法研究进展

牛呼吸道疾病综合征是引起世界范围内饲养牛发病和死亡的主要原因,严重危害着养牛业的发展。本文介绍了牛副流感病毒3型的病原学检测方法,包括病毒分离与鉴定、分子生物学检测方法和血凝试验,以及血清学检测方法,包括血凝抑制试验、免疫荧光试验、中和试验、酶联免疫吸附实验和液相芯片技术等。通过综述近年来牛副流感病毒3型的最新实验室检测方法研究进展,为该病检测和诊断提供参考。     

Studies with Bovine Parainfluenza — 3 Virus in U.A.R. (Egypt)

A bovine strain of myxovirus parainfluenza-3 (MP3) virus, designated S virus, was isolated from lung tissue collected from cattle with respiratory illness in 1963. The virus agglutinates mammalian and avian erythrocytes, and is sensitive to ether, sodium desoxycholate and trypsin. It grows in primary calf kidney, buffalo kidney, dog kidney, camel kidney and MS cell cultures. The S virus forms well-defined plaques in buffalo and calf kidney cells on the 5th or 6th day after inoculation. Examination of cell cultures following inoculation with S virus revealed giant cell formation, and introcytoplasmic and intranuclear inclusions. At 37°C the virus titer dropped from 10^10.4 to 10^2.6 in 3 days. Virus was completely inactivated at 56°C within 15 minutes. Growth-curve studies in tissue culture monolayer cells revealed a latent period of 10 hours. The intracellular virus titer was slightly lower than that of extracellular virus. The isolate was identified as MP3 virus by serum neutralization and hemagglutination-inhibition tests. Antibodies (HI) to S virus were shown to be present in a significant proportion of Egyptian cattle. The epidemiological significance of MP3 (bovine strain) virus in U.A.R. is discussed.     

The influence of complement on the neutralization of infectious bovine rhinotracheitis virus by globulins derived from early and late bovine antisera.

Calves were inoculated at four week intervals with infectious bovine rhinotracheitis virus (IBRV). Sera were obtained at eight days (early sample) and 21 days (late sample) after each inoculation. Kinetic neutralization was carried out with 7S and 19S globulins derived from these sera, both in the presence and in the absence of guinea pig complement (C). In all instances the 19S neutralizing antibody (AB) was dependent on C for neutralization of IBVR. However, C dependency was not observed with any of the 7S preparations. Neutralizing activity was readily detected in 19S globulins from the early sera after primary and subsequent inoculations but not in any of the late sera. Early sera collected after primary inoculation did not contain any 7S neutralizing AB but it was present in all the other sera tested. The 7S AB when present was always at a considerably higher concentration than 19S AB. Thus it may be possible to determine whether cattle have recently been exposed to IBRV when paired serum samples are not available by determining the presence of C-dependent 19S globulins. In addition, by comparing 19S and 7S levels, a distinction may be made between primary and secondary responses to IBRV.     

Hemolytic complement titers and complement C3 levels in endotoxin-induced mastitis

Escherichia coli lipopolysaccharide B was instilled through the lactiferous duct of cows to induce acute mastitis. Hemolytic complement (C) activity and C3 concentrations were determined in blood serum and in renninprecipitated whey before, and at certain times after, mastitis was induced. Hemolytic complement activity was detected in the whey only during the first 36 hours after endotoxin was instilled, whereas activity was not seen before and 48 or more hours after the endotoxin was given. The maximum titer as measured with the guinea pig RBC/bovine natural antibody system was 1:64. The C3 concentrations in normal whey (before installation of endotoxin), measured by radial immunodiffusion, were between 1% and 4% of the base-line blood serum values (pool from healthy cows). The whey concentration of C3 increased (to 5% to 18%) during the first 8 hours of mastitis. However, at 72 hours, the whey values were back to preinstillation concentrations in all quarters.     

牛副流感病毒3型毒株的分离鉴定及基因组遗传变异分析

从新疆地区某牛场出现发热、咳嗽等症状的多例病牛的肺组织中分离得到3株牛副流感病毒3型,分别命名为XJ03、XJ022、XJ023,对其中两株病毒XJ03和XJ023的基因组进行序列测定,测序结果显示,XJ03和XJ023毒株基因组全长分别为15474 bp(Gen Bank登录号为KU198929)和15475 bp,其核苷酸同源性为99.89%。同代表性的牛副流感病毒基因组比对发现,与我国的山东毒株SD0835同源性最高为99.3%,均属C型BPIV。在C型毒株中,与南韩12Q061分离株(C型)同源性最低为97.5%。F、N、HN、L、P、M蛋白基因氨基酸序列分析显示,与SD0835毒株相应序列对比,同源性分别为99.63%、92.15%、99.48%、99.28%、98.50%和100%,部分氨基酸发生了新的变异。试验结果将为今后更好地开展BPIV3防控奠定基础。     

牛副流感病毒3型RT-LAMP检测方法的建立及应用

本试验根据GenBank中登录的牛副流感病毒3型(BPIV-3)基因序列,利用在线软件Primer Explorer V4 Software和Primer Premier 5.0,针对BPIV-3 NP基因序列的保守区设计并筛选了一套环介导逆转录等温核酸扩增(RT-LAMP) 引物,建立BPIV-3特异性检测的RT-LAMP方法。在Bst DNA聚合酶作用下,63 ℃恒温反应1 h即可完成扩增过程,扩增产物通过浑浊度比较、凝胶电泳和肉眼可视化进行判定。结果表明,该方法比RT-PCR敏感度更高,最低检出量可达0.069 fg/μL。该方法可用于牛副流感病毒3型的实验室检测和临床初步诊断。     

Growth of several strains of Chlamydia psittaci in Vero and McCoy cells in the presence of cytochalasin and cortisone.

Chlamydia psittaci of avian and mammalian origin were grown in McCoy and Vero cells in the presence of cytochalasin B with cortisone acetate. Six turkey strains, one parrot strain, one human strain, one ovine strain and one bovine strain were used in this study. All strains, except the turkey strain NJ-1, grew to higher titers in Vero cells than in McCoy cells. Five of the six turkey strains could be grouped together because they induced cytopathic changes rapidly. The other turkey strain, along with the parrot, human and ovine strain, induced cytopathic changes more slowly and the bovine strain failed to cause cytopathic changes, but it did replicate in the cell culture system.     

牛副流感病毒3型N基因的克隆与系统进化分析

扩增大庆地区分离的牛副流感病毒3型的N基因,并进行同源性分析。设计特异性引物,通过聚合酶链反应扩增牛副流感3型N基因,将该基因分别连接到克隆载体的BamHⅠ、HindⅢ酶切位点中,测定插入片段的核苷酸序列,并利用分子生物学软件进行同源性分析。序列分析结果表明,扩增获得BPIV-3-N基因全长1 548bp,编码515个氨基酸,该N段基因核苷酸序列及所推导的氨基酸序列与GenBank中日本分离株910N基因序列同源性较高,核苷酸同源性为99.7%,氨基酸同源性为100%。     

Development of post-weaning diarrhoea in piglets. Relation to presence of Escherichia coli strains and rotavirus

Weaning of piglets complicated with an exposure to pathogenic strains of Escherichia coli was scrutinized in two sets. The first set comprised 20 animals representing two litters and the second set included 30 animals from five litters. The piglets were either left as controls or exposed to one or three pathogenic strains of E. coli. Aiming to simulate a natural exposure the challenge strains were spread on the floor of the pens at weaning. In addition the pigs experienced several non-infectious stress factors commonly occurring at that occasion. Some groups were given adrenocorticotropic hormone (ACTH), aiming to simulate a stressful weaning. The balance and the composition of the faecal coliform populations, measured by a metabolic fingerprinting method, was disturbed among all animals following weaning. This disturbance was more pronounced and lasted longer among piglets exposed to pathogenic strains of E. coli. All piglets exposed to pathogenic E. coli shed these strains in faeces. Diarrhoea was induced in the groups exposed to E. coli, but not among the control animals. Pigs not treated with ACTH and subjected to a single pathogenic strain of E. coli became infected but did not develop diarrhoea unless if coinciding with shed of rotavirus. Control pigs excreting rotavirus had no diarrhoea. Diarrhoea was most frequent in the groups exposed to three pathogenic strains of E. coli, and in these groups diarrhoea was seen in the absence of rotavirus. ACTH administration amplified the clinical signs. The litter of origin influenced the development of post-weaning diarrhoea.