Similarity of avian paramyxovirus serotype 1 isolates of low virulence for chickens obtained from contaminated poultry vaccines and from poultry flocks

At present Denmark has the status of a 'non-vaccinating' country for Newcastle disease and its poultry population should therefore be free of antibodies to avian paramyxovirus 1 (APMV-1). Three live avian vaccines against infectious bronchitis, avian encephalomyelitis, and chick anaemia which had been found to be contaminated with APMV-1 viruses of low virulence for chickens were examined. The vaccines were produced by the same company and the affected batches had been used in Denmark in 1996/97. Furthermore, APMV-1 isolates of low virulence were obtained from three commercial broiler breeder flocks, one of which had been vaccinated with two of the contaminated vaccines. The flocks belonged to the same hatchery organisation. A comparison of viral F0 gene sequences and typing of virus isolates with a panel of monoclonal antibodies showed that the vaccine and field isolates were identical.     

Avian paramyxovirus serotype 1 (Newcastle disease virus)--infections in falcons.

From eight falcons and one pigeon which died from NDV over a period of 15 months in Dubai, United Arab Emirates, PMV-1 viruses were isolated on quail embryo cell cultures. The identification of all 9 strains were achieved with the haemagglutination inhibition test against polyclonal chicken PMV-1 antiserum, against mouse monoclonal antibodies as well as with the immunoperoxidase test. Intracerebral pathogenicity index and intravenous pathogenicity index tests were also carried out. Although the virus isolates in this study fell into two distinct groups, the overall clinical symptoms displayed by the falcons tailed to demonstrate any trends or specificity unique to a group. The isolate obtained from a pigeon was similar to the isolates from one group of the falcons and showed no identity with the pigeon variant virus.     

禽Ⅰ型副粘病毒各种禽源分离株的免疫原性

分别制备了源于鸡、鹅、鸽、鹌鹑、孔雀、画眉鸟、珍珠鸡的禽型副粘病毒(APMV-1)7个强毒分离毒株和商品弱毒疫苗株克隆30(C30)的灭活油乳剂苗,并用这8种灭活油乳剂苗和C30株的活疫苗分别在鸡、鹌鹑、鹅和鸽进行了免疫及交叉攻毒保护试验。免疫后(PI)分别测定试验禽血清的新城疫病毒(NDV)血凝抑制(HI)抗体的滴度,并于PI 5周用强毒株进行攻毒。结果表明,鸽的HI抗体几何平均滴度(MAT)为9.00~10.0 log2,鸡的为7.13~7.63 log2,鹌鹑的为5.00~5.13 log2,鹅对灭活油乳剂苗的为5.63~6.38 log2、而对C30株活疫苗的仅为3.38log2;除了C30株活疫苗免疫鹅提供的保护率比较低(20%)外,8种油乳剂苗都能对同源或者异源强毒株的攻毒提供比较高的保护率(66.75%~100%)。研究结果表明,经典疫苗株C30与近年来从各种不同禽类分离的致病性APMV-1野毒株之间、不同禽源分离株之间的抗原性,以及各种不同禽源分离株的之间的免疫原性差异均不大。     

鸽Ⅰ型副粘病毒F基因的序列分析

本研究采用RT-PCR方法成功地获得了3个鸽I型副粘病毒广东分离株(P4、P5和P7的F基因片段。经测序表明，基因片段长度均为1290bp；经序列分析发现，毒株P4与NDV标准株La Sota和C30的同源性最高，达到99．4％；而毒P5、P7与La Sota和C30的同源性相对较低，为83％。从建立的系统发育树可看出，毒株P4与NDV标准株La Sota和C30有很近的亲缘关系，而毒株P5、P7与NDV标准株La Sota和C30的亲缘关系相对较远。     

Isolation, identification, and comparison of four isolates of avian paramyxovirus serotype 2 in China

Four Yucaipa-like viruses of avian paramyxovirus serotype 2 (APMV-2) were isolated in China from the imported Gouldian Finch (Chloebia gouldiae) and broilers in 1998-2002, and were named F4, F6, F8, and NK, respectively. Examined under electron microscope, the isolates were found to be round in shape and varying in size. The results of the hemagglutination inhibition test and indirect enzyme-linked immunosorbent assay (using monoclonal antibodies) showed some differences between the isolates and the reference strain Yucaipa. The isolates derived from chickens had a closer relationship to Yucaipa virus than did those of finches. Sequence comparison of the fusion gene and the haemagglutinin-neuraminidase gene showed similar results, although the variations were lesser among APMV-2 viruses in nucleotide and amino acid sequence. By sequence comparison, it was also revealed that at the molecular level the four virus strains belong to APMV-2, and that two of the strains were isolated from the same group of imported Gouldian Finches.     

A paramyxovirus of serotype 3 isolated from African and Australian finches

Two virus isolates were obtained from exotic finches (Ortygospiza atricollis and Poephila cincta) suffering from apathy, diarrhea, conjunctivitis, and dysphagia. The isolates were identified as paramyxoviruses based on their multiplication characteristics in embryonating chicken eggs, chicken embryo fibroblasts, and chicken embryo kidney cell cultures, on morphology upon electron microscopy, and on other biological properties. Both isolates were serologically related to the reference strain of the paramyxovirus serotype 3. Intravenous infection of 42-day-old chicks resulted in no clinical signs, but intracerebral infection of 1-day-old chicks resulted in mortality and intracerebral pathogenicity indices of 0.25 to 0.35. Of five finches from various species inoculated with isolate 840/85, three remained clinically healthy through 6 weeks, but two died: one (Poephila cincta) 5 days postinoculation after showing nervous distress, and the other (Amandava amandava) suddenly 42 days postinoculation.     

禽Ⅰ型副黏病毒不同禽源株P基因编码蛋白的分子特征分析

采用RT-PCR技术对禽Ⅰ型副黏病毒鸡源分离株(WF00C)、鹅源分离株(WF00G)和鸽源分离株(WF00P)P基因进行了克隆和序列分析。结果表明:这些毒株的P基因最大ORF的长度均为为1188bp,编码395个氨基酸。P蛋白同源性和系统发育分析显示,WF00C株和WF00G株与NA-1、ZJ1、FP1/02、PX2/03、Duck/1/05、SP02和SRZ03的同源性较高,WF00P株与意大利鸽源分离株IT-227/82、2736/00和法国鸽源分离株99106、99299的亲缘关系较近,而且WF00C株、WF00G株和WF00P株均与传统疫苗株或弱毒株HB92、LaSota、Clone30和B1以及国内标准强毒株F48E9的遗传距离较大,这预示目前流行的APMV-1已经发生了较大程度的变异。V蛋白羧基端氨基酸比对分析发现,APMV-1V蛋白的特有序列有较高的一致性,即氨基酸序列(132KKG134)和V蛋白羧基端的5个Cys残基位点在所有的毒株中是高度保守的,但在138～170位和201～240位存在较大的变异,APMV-1毒株V蛋白羧基端氨基酸的突变呈现"基因型一致性"。     

Avian paramyxovirus type 1 infection of racing pigeons: 3 epizootiological considerations

During July to December 1983 birds in 192 racing pigeon lofts were confirmed as infected with paramyxovirus type 1 virus on the basis of disease signs alone when contact with infected cases was known (10) or with supporting serology (130), virus isolation (eight) or both (44). These outbreaks were mainly concentrated in south Wales (89) and Dorset (40). In all, 29 counties of Great Britain were involved. In the majority of outbreaks (69 per cent) activities associated with racing were strongly implicated in the spread of the disease but trade in birds, stray bird contact, loft visits and contact at shows were also possible methods of spread. Although considerable variation was seen in the pathogenicity of the viruses isolated from affected birds there were no apparent epizootiological links between isolates of similar virulence.     

In vitro characterisation of high and low virulence isolates of equine herpesvirus-1 and -4

Basic in vitro characteristics of high and low virulence isolates of equine herpesviruses-1 and -4 were investigated with particular reference made to the Ab4 and V592 isolates of EHV-1 as both have distinct endotheliotropism and clinical outcomes in pony challenge studies. Additionally, some EHV-4 isolates that showed variations in clinical outcome were included in some experiments. The aim of the study was to identify an in vitro characteristic that would differentiate strains of known virulence. Such a system could then be applied to vaccine and virulence studies as an effective screening tool. Viral growth kinetics in a variety of cell culture systems, plaque size, ability to replicate in fetal endothelium in organ culture, and sensitivity to acyclovir were compared. No reliable marker system that differentiated between higher and lower virulence isolates of EHV-1 and EHV-4 was identified.     

Avian paramyxovirus type 1 infections of racing pigeons: 4 laboratory assessment of vaccination

The immune response and protection from challenge afforded to adult pigeons by four different vaccination schedules were assessed. Intravenous challenge with a field pigeon isolate was done four weeks after the second of two doses of vaccine given four weeks apart. Little difference in protection was seen between two 0.25 ml and two 0.5 ml doses of oil emulsion vaccine, although the latter produced a slightly higher immune response. In both cases one of 10 challenged pigeons became sick and died. One dose of Newcastle disease virus B1 live vaccine followed four weeks later by 0.5 ml oil emulsion vaccine gave a comparable immune response to two 0.25 ml doses of oil emulsion but only six birds survived challenge. Two doses of Newcastle disease virus B1 vaccine gave a poor immune response and little protection from challenge; all 10 birds became sick and eight died. Assessment of the onset of protection following one dose of either 0.5 ml oil emulsion vaccine or Newcastle disease virus B1 indicated some partial protection in the latter group as early as five days after vaccination. Both groups showed protection at 10 days but by 21 days, although protection was sustained in the oil emulsion group, birds receiving live vaccine were fully susceptible. Measurement of the duration of protection in pigeons given two 0.5 ml doses of oil emulsion vaccine indicated that protection had begun to wane by 40 weeks after the first dose.     

鸽Ⅰ型副黏病毒的分离鉴定及其F基因、HN基因的序列分析

利用RT-PCR技术,将从江苏省分离到的2株鸽源NDV的融合蛋白(F)和血凝素神经氨酸酶(HN)基因重要功能区片段进行扩增和序列分析,发现F蛋白多肽裂解位点的氨基酸序列为112K-R-Q-K-R-F117,符合NDV强毒株序列特点.F基因分型及同源性比较显示,分离到的2株鸽源NDV PG-CH-JS-1-05,PG-CH-JS-1-06属基因Ⅵ型.与国内参考毒株YN-P1 F基因推导的氨基酸序列同源性最高为96.4%,与LaSota的同源性为84.1%～84.2%,与F48E9的同源性为86.0%～86.2%;与国外参考毒株Warwick66的同源性为92.7%～93.3%;HN基因氨基酸序列同源性比较显示,与PB9601的同源性最低,只有3.4%～3.7%,与LaSota的同源性也较低,为88.5 % ～88.7%.而与国外参考毒株IT-227-82的氨基酸序列同源性为95.4%～95.6%,与Pigen-NY-US-1984的同源性为94.8%～94.9%,与248 V B的同源性为92.5%～92.7%,说明与国外鸽源NDV分离毒株的遗传距离较近.     

Avian paramyxovirus type 1 infection of racing pigeons: 5. Continued spread in 1984

The neurotropic disease of pigeons caused by a variant avian paramyxovirus type 1 virus was confirmed in 866 lofts in Great Britain during 1984, in comparison with 192 lofts during July to December 1983. The 1984 outbreaks were spread over 48 counties in England and Wales and three regions in Scotland. The main methods of spread of disease in the 1984 outbreaks appeared to be similar to 1983 with 574 of 866 probably resulting from contact with infected birds at, or travelling to, races or shows. In 791 of 866 (92.5 per cent) outbreaks in 1984 disease was seen only in unvaccinated birds. A further 61 (7 per cent) occurred in inadequately vaccinated birds or birds vaccinated after clinical signs appeared.     

Prevalence of the virulence plasmid in Salmonella Typhimurium isolates from pigs

To determine the prevalence of the virulence plasmid in Salmonella Typhimurium isolates from pigs in Japan, a total of 106 porcine isolates were subjected to PCR amplification for the detection of the virulence plasmid. Out of the isolates of S. Typhimurium, 38 (35.8%) harbored the virulence plasmid. The presence of the virulence plasmid was widely observed in the isolates from systemically infected pigs (92.0%, 23/25), compared with diarrheic (18.8%, 12/64) and apparently healthy pigs (17.6%, 3/17) (P<0.01).     

番鸭副粘病毒1型的分离鉴定

自表现神经症状、腹泻、病死率较高、腺胃粘膜局灶性出血或溃疡及肠道粘膜出血为特征的病死番鸭肝脏中分离到病毒,经电镜观察、血凝及血凝抑制试验鉴定为副粘病毒1型.以SPF鸡胚测定其平均致死时间(MDT)为51 h,对1日龄SPF鸡的脑内接种致死指数(ICPI)为1.74,表明该毒株属强毒株.经肌肉注射途径攻击10 d雏番鸭致死率达66.7%,表明该分离毒对雏鸭有高度的致病性.