Pathogenic properties of Newcastle disease virus isolates in the Sudan.

Six Newcastle disease virus (NDV) isolates were obtained from disease outbreaks on different poultry farms in the Sudan between 1988 and 1991. The pathogenic properties of these isolates were studied in comparison to those of strain Herts 33/56. All the isolates were similar in that they killed chicken embryos quickly, in mean death time (MDT) and embryo lethal dose 50 per cent (ELD50), had higher intracerebral pathogenicity indices (ICPI), and produced viscerotropic lesions in the infected chickens. The field isolates had the characteristics of the velogenic viscerotopic strains of NDV. The pathogenesis of infection caused by one of the isolates was studied. The virus was first detected in different organs and in oral and cloacal swabs on the third day after infection.     

Characterisation of Newcastle disease viruses isolated in India.

Eleven Newcastle disease virus (NDV) isolates obtained from outbreaks of disease in chickens (9) and Japanese quail (2) in Tamil Nadu, India were characterised in pathogenicity tests, antigenically, using mouse monoclonal antibodies (MAbs), and other established tests devised to distinguish between different strains. All 11 isolates were shown to be highly virulent for chickens. In indirect immunoperoxidase tests used to assess the ability of a panel of 28 MAbs to bind to infected cell cultures, 10 of the isolates showed an identical reaction pattern, the other isolate (No. 4) failed to react with one MAb which bound to cells infected with the other isolates. Isolates 9 was unstable at pH 3 while the other 10 were stable. All other properties were shared by the 11 isolates.     

新城疫病毒山东强毒株的分离鉴定

从山东流行烈性传染病的鸡群中分离出7株具有血凝活性的病毒，该7株病毒的血凝活性均能被新城疫La Sota株标准阳性血清所抑制，但病毒不能被中和，仍能致死鸡胚。经分离鉴定，分离毒均为新成疫病毒株。通过鸡胚半致死量（ELD50）、最小致死量致鸡胚的平均时间（MDT）、1日龄雏鸡脑内致死指数（ICPI）、6周龄雏鸡静脉致死指数（IVPI）、血凝解脱及血凝素稳定性等试验表明：7株分离病毒均为新城疫病毒强毒性，其毒力与标准强毒株F48E9株相似。     

Characterization of pigeon-origin Newcastle disease virus isolated in China

Fourteen pigeon-origin Newcastle disease virus (NDV) isolates were obtained from sick pigeons in China between 1996 and 2005. The mean death time (MDT) of embryonated eggs and the intracerebral pathogenicity indices (ICPI) were tested to determine the virulence of the field isolates. The result indicated that most isolates were proved to be mesogenic (MDT 60-90 hr and ICPI > 1.2). The main function regions of F protein gene of the isolates were amplified and sequenced for phylogenetic and residue substitutive analysis. The fusion protein cleavage site sequences of most isolates had multiple basic amino acids R/KRQKRF at positions 112-116 and a phenyl alanine at position 117, characteristic of velogenic isolates. In the phylogenetic tree, the majority of the isolates were clustered into a single genetic lineage, termed genotype VIb, and were typical pigeon paramyxovirus type 1, whereas a small number of recent isolates (three strains) were grouped into genotype VIId, a predominant genotype responsible for most Newcastle disease outbreaks in chickens and geese since the end of last century. One isolate, PK9901, was proved to be a lentogenic strain, of genotype II NDV, to which the vaccine strain La Sota belongs.     

Antigenetically Unusual Newcastle Disease Virus from Racing Pigeons in India

Newcastle disease virus isolated from an outbreak in racing pigeons in India was found to be velogenic, based on the mean time to death in 10-day-old embryonated hen's eggs, the intravenous pathogenicity index in 6-week-old chickens and the pathogenesis in chickens and pigeons. The virus induced disease in chickens without prior adaptation in chickens. The virus was antigenically unusual since it could not be grouped with the available panel of monoclonal antibodies at the World Reference Laboratory for Newcastle disease, UK. However, commercially available lentogenic and mesogenic vaccines provided 100% protection to chickens against this antigenically unusual NDV.     

鸵鸟新城疫病毒野毒株的分离及其生物学特性

用鸡胚从疑似鸵鸟新城疫的送检病料中分离到 2株病毒。 2株病毒均能凝集鸡红细胞 ,且能被抗新城疫病毒 ( NDV)阳性血清抑制 ;用抗 NDV单抗 PEG夹心 ELISA测定 2株分离毒均为阳性。对其中 1株作进一步生物学特性鉴定 ,按照国际上规定的 NDV毒力判定标准测定的该毒株最低致死量致死鸡胚的平均死亡时间 ( MDT)为 54h,1日龄雏鸡脑内接种致病指数 ( ICPI)为 1 .88,6周龄雏鸡静脉接种致病指数 ( IVPI)为2 .75。结果表明 ,本分离株为鸵鸟新城疫病毒强毒     

鸡新城疫地方强毒株的分离与毒力鉴定

在河北保定地区疑似新城疫的鸡群中,分离到两株具有血凝性的病毒,与多种阳性血清进行血凝抑制试验,确定两株分离株均为新城疫病毒。对两株病毒的毒力进行了鉴定,测定鸡胚最小致死量平均死亡时间(MDT)分别为52h和54h;1日龄雏鸡脑内接种致病指数(ICPI)分别为1.93和1.86;6周龄鸡静脉内接种致病指数(IVPI)分别为2.92和2.72。结果表明:这两株分离株均为新城疫强毒株。     

Pathogenicity and cross-protection of pigeon paramyxovirus-1 and Newcastle disease virus in young chickens

Avian paramyxovirus-1 (PMV-1) isolates from Delaware racing pigeons were compared with Newcastle disease virus (NDV) in pathogenicity and cross-protection studies in young chickens. The pathogenicity of pigeon PMV-1 isolates was more closely related to mesogenic (Roakin) NDV than to lentogenic (La Sota) or velogenic (Texas GB) NDV strains. Pigeon PMV-1 produced 100% mortality in 1-day-old NDV-susceptible chickens following intratracheal and intracerebral inoculation. Laboratory tests often used in conjunction with chicken pathogenicity procedures for patho-typing NDV gave conflicting results. Pigeon PMV-1 isolates produced large clear plaques (up to 3.5 mm) in chicken-embryo-fibroblast cultures. Chicken embryo mean death times were considerably greater for pigeon PMV-1 (88 and 109 hr) than for Roakin (66 hr) and Texas GB (48 hr). B1 strain NDV and pigeon PMV-1 produced complete cross-protection in challenge studies in chickens. Extensive cross-reaction between pigeon PMV-1 and NDV occurred in hemagglutination-inhibition tests using polyclonal antisera. However, pigeon PMV-1 and NDV were readily distinguishable using a NDV monoclonal antibody, 2F12.     

鸽新城疫病毒的分离鉴定

用SPF鸡胚从疑似鸽新城疫的信鸽饲养场分离到一株新城疫病毒。分离株利用电镜负染技术观察到典型的新城疫病毒粒子。生物学试验表明,该株病毒具有较强的毒力,最小致死量鸡胚平均致死时间（MDT）为68.4小时,1日龄雏鸡脑内接种致病指数（ICPI）为1.375,6周龄雏鸡静脉接种致病指数（IVPI）为1.34,在鸡胚成纤维细胞上能引起细胞病变。动物回归试验证明,分离株能致2月龄鸽死亡。     

1株基因Ⅶ型新城疫病毒的生物学特性研究及全基因组序列分析

为研究当前流行的新城疫病毒（Newcastle disease virus,NDV）基因型、致病性及其与传统新城疫病毒疫苗株（La Sota等）的核苷酸差异,试验从某发病鸡场病死鸡体内分离到1株疑似NDV毒株,经红细胞凝集试验（HA）和红细胞凝集抑制试验（HI）初步确定为鸡源NDV。参照GenBank公布的NDV F基因部分片段（登录号：JF950510.1）设计1对引物,通过RT-PCR技术扩增分离株的F基因并克隆、测序,测序结果与NCBI中NDV F基因序列进行比对,构建系统进化树并分析其基因型;通过测定鸡胚平均致死时间（MDT）、1日龄鸡脑内致病指数（ICPI）和6周龄鸡静脉致病指数（IVPI）判断病毒致病性;参照GenBank公布的NDV全基因组序列（登录号：JF950510.1）设计9对引物对分离株进行全基因组序列测定,并分析其基因组结构。结果表明,RT-PCR扩增得到F基因长约500 bp,基于F基因构建的系统进化树显示分离株为基因Ⅶ型NDV;MDT、ICPI和IVPI分别为52.8 h、1.675和2.46,表明分离株属于强毒株。全基因组序列分析显示,分离株全基因组全长15 192 bp,与传统La Sota株基因组相比,序列多出6个碱基,核苷酸序列同源性82.8%。本研究成功分离到1株基因Ⅶ型NDV强毒株,且与传统疫苗毒株La Sota的核苷酸序列同源性差异较大。     

Serological and pathological studies of Newcastle disease viruses isolated from caged birds from Southeast Asia

Eleven isolates of Newcastle disease virus (NDV), from caged birds imported from or captured in Southeast Asia in 1979-80, were antigenically divided into five distinct groups. Most of them were distinguishable from more classical NDVs (vaccine B1 strain and Miyadera strain) on the basis of their reactivity to eight monoclonal antibodies against the HN molecule of NDV in hemagglutination-inhibition tests. However, when three representative isolates were evaluated for their biological properties and pathogenicity against 1-day-old chickens, all three were found to be velogenic types that could induce serious symptoms of Newcastle disease and which eventually killed all of the chickens, regardless of the route of infection. There was not any significant correlation between their reactivity patterns with the monoclonal antibodies and their virulence.     

新城疫单抗ELISA试剂盒检测鸽新城疫病毒

用新城疫（ND）单抗酶联免疫（ELISA）试剂盒检测23例疑似ND的鸽泄殖腔棉拭样品，7份阳性样品用SPF鸡胚均会离到病毒，该病毒凝集鸡红细胞，并就抗新城疫病毒（NDV）阳性血清所抑制，其中4株病毒的MDT在48－68.6h之间，ICPI为1.55-1.85。试验结果表明所分离的病毒为NDV，亦表明ND单抗ELISA试剂盒能够检出鸽NDV，并可作为鸽群中NDV流行病学调查的有效手段。     

鸡新城疫病毒河北分离株F基因的分子特性分析

通过毒力测定、RT-PCR及F基因的序列测定与遗传进化分析,对2005-2008年从河北省部分地区的发病鸡群中分离到的10株新城疫病毒（NDV）进行了研究。各分离株经典毒力测定结果显示：MDT在37.6～54.4h之间,ICPI在1.71～2.0之间,IVPI值在2.16～2.8之间,均为新城疫病毒强毒株特征。F基因的序列测定表明,分离株之间的核苷酸序列具有77.4%～98.0%的同源性,与疫苗株Lasota的同源性为87.0%～98.9%,与国内标准强毒株F48E9同源性为89.7%～98.9%。推导其氨基酸序列分析表明,8个分离株的F蛋白的裂解位点氨基酸组成为112 R-R-Q-K-R-F117,具有NDV强毒株特征,与毒力测定结果相符,2个分离株的F蛋白的裂解位点氨基酸组成为112 G-R-Q-G-R-L117,与弱毒株特征相符。F基因分型和同源性比较显示：目前河北新城疫的流行以基因Ⅶ型为主（占70%）,同时兼有基因Ⅱ型（占20%）和基因Ⅸ型（占10%）。     

鸭副粘病毒强毒株的分离和鉴定

采用鸡胚接种法从安徽凤阳某患病肉鸭群中分离到一株病毒。该素株对鸡红细胞具有凝集性，并可被康复鸭鸭血清和NDV阳性抗血清所抑制，而不能被禽流感标准阳性血清抑制，结合血清中和鸡胚接种试验，病毒回归试验和免疫防治效果的研究结果，确认为鸭副粘病毒。参照国际上规定的新城疫病毒毒力判定的标准及其方法，测定该分离株的鸡胚最小致死量平均死亡时间（MDT），1日龄鸡及脑内接种致病指数（ICPI）和6周龄鸡静脉内接种致病指数（IVPI）分别为48.9h,1.80和2．45。表明该鸭副粘病天线离株具有新城疫病毒（NDV）速发型相类似的毒力，属强毒力毒株，并定名为WF00D株。     

鸽新城疫病毒野毒PB9601株的致病性研究

用不同方法测试了从新城疫患鸽分离到的新城疫病毒（ＮＤＶ）野毒ＰＢ９６０１株的致病性。结果,该毒株对１日龄ＳＰＦ雏鸡的脑内接种致病指数为２．００,对６周龄ＳＰＦ鸡静脉接种致病指数为０．００;该毒株对６周龄左右鸽有很强的致病性,有的血清中已有一定量的抗鸽ＮＤＶ抗体;经ＳＰＦ鸡胚传１３代的尿囊液病毒对鸽的半数致死量约为１２个ＴＣＩＤ５０。由此认为,ＰＢ９６０１株ＮＤＶ是对鸡致病性很弱但对鸽呈高度致病性的毒株,可作为国内鸽ＮＤＶ强毒的参考株。     

INTERACTION BETWEEN INFECTIOUS BURSAL DISEASE VIRUS AND NEWCASTLE DISEASE VIRUS IN CHICKENS

The Australian strain of infectious bursal disease virus (IBDV), 002/73, affected the response of chickens to Newcastle disease virus (NDV). The titre of serum antibodies to NDV in chickens infected with IBDV was significantly lower than that of birds infected with NDV alone. It also appeared that IBDV affected NDV excretion from chickens as NDV was more frequently isolated from chickens infected with IBDV, IBDV infection did not alter the pathogenicity of NDV in chickens. This Australian strain of IBDV therefore appeared to be immunodepressive in one-day-old chickens.     

鸭源新城疫病毒的分离鉴定

从病死肉鸭肝脏中分离到2株病毒(ZH1、ZH2),均能够凝集鸡、肉鸭、绵羊、山羊、猪、人、兔、牛等的红细胞,且这种血凝性可被NDV标准阳性血清所抑制.参照NDV毒力判定标准及其方法对分离毒株ZH1、ZH2进行了鸡胚最小致死量平均死亡时间(MDT)、鸡胚半数感染量(EID50)以及1日龄鸡脑内接种致病指数(ICPI)测定,结果ZH1、ZH2株的MDT为52 h和44 h,EID50为106.4/0.1mL和108.64/0.1mL,ICPI为1.93和1.975.表明这2株分离病毒均为NDV强毒株.     

Newcastle disease outbreaks in western China were caused by the genotypes VIIa and VIII

Twelve Newcastle disease virus (NDV) strains were isolated from chickens involved in outbreaks of Newcastle disease (ND) in western China (Shaanxi, Gansu, Xinjiang, Qinghai and Guangxi provinces) between 1979 and 1999. All strains were determined to be velogenic by plaque formation, the mean death time (MDT) of embryonated eggs, and the intracerebral pathogenicity index (ICPI). For preparation of virus RNA, the acid guanidinium-thiocyanate method was used. A 908bp fragment of nucleotide was amplified by RT-PCR starting from the N terminal of the F gene and the PCR segments were cloned into the PGEM-T vector and sequenced. The similarities of the nucleotide sequences (1-519bp) and predicted amino acid sequences of the F gene (1-125) were analyzed by comparing the 12 NDV isolates with the NDV vaccine strains Lasota, B1, H1 and V4, with classical NDV strains and recent epizootic strains. Phylogenetic analysis demonstrated that all strains were of two novel genotypes; the NDV strains that caused the outbreak of ND in western China during 1998-1999 was of the genotype VIIa, whereas the strains from the Qinghai province (1979-1985) were of genotype VIII, which has been found predominately in southern Africa.     

新城疫病毒西藏分离株的生物学特性鉴定及遗传进化分析

从西藏病死藏鸡中分离到具有血凝活性的病毒、经血凝抑制试验、电镜观察、PCR扩增和测序鉴定为新城疫病病毒(NDV),通过动物致病性试验证明该病毒对鸡具有致病性;分离毒株毒力测定结果显示,MDT为120h,EID50为10-8.44、IVPI为0.5、ICPI为0.6,均符合NDV弱毒株特征。血凝解脱及血凝素热稳定性试验显示:各分离株的血凝解脱时间短,血凝素热稳定性较差,符合NDV弱毒株的特征。F基因的序列测定遗传进化分析表明,西藏分离毒株之间的核苷酸序列具有99%的同源性,与疫苗株LaSota的同源性为90%;与国内标准强毒株F48E8同源性为81%。推导其氨基酸序列分析表明,各分离株的F蛋白的裂解位点氨基酸112 G-K-Q-G-R-L117,具有NDV弱毒株特征,与毒力测定结果相符。本研究首次报道了NDV西藏分离毒株遗传进化情况和生物学特性情况,为进一步研究高海拔、缺氧环境下NDV生物学特性变化研究奠定了基础。     

鸽新城疫病毒的分离及其生物学特性测定

用ＳＰＦ鸡胚从疑似鸽新城疫（鸽ＮＤ）病鸽群中分离到一株病毒ＱＬ株,该病毒株能凝集鸡红细胞（ＲＢＣ）,这种凝集作用能被抗新城疫病毒（ＮＤＶ）阳性血清抑制;用抗ＮＤＶ单抗ＰＥＧ夹心ＥＬＩＳＡ测定分离株为阳性。分离株经肌肉注射能使鸽发病和死亡,出现与自然发病鸽一致的症状和病变,但肌注ＳＰＦ鸡只感染,不见临床症状。对该分离株作进一步生物学特性鉴定,按照国际上规定的ＮＤＶ毒力判定标准,测定了该毒株最低致死量致死鸡胚的平均死亡时间（ＭＤＴ）、１日龄雏鸡脑内接种致病指数（ＩＣＰＩ）和６周龄雏鸡静脉接种致病指数（ＩＶＰＩ）,结果ＭＤＴ为１０５小时、ＩＣＰＩ为１．３３、ＩＶＰＩ为１．０。试验结果表明本分离株为鸽新城疫病毒。