斗鸡新城疫病毒的分离与生物学特性鉴定

从病死的越南斗鸡脑组织中分离到l株病毒,能凝集鸡的红细胞,而且这种凝集能被新城疫阳性血清特异性抑制。通过对分离株进行RT—PCR检测、动物致病性试验、MDT与ICPI值测定,证实为中等偏强毒力新城疫病毒。动物感染试验表明,20日龄非免疫鸡感染分离毒后24～120h可用RT—PCR方法从喉头和泄殖腔检出新城疫病毒。     

Reduced serologic response to Newcastle disease virus in broiler chickens exposed to a Chinese field strain of subgroup J avian leukosis virus

In this study, a Chinese field strain of subgroup J avian leukosis virus (ALV-J), NX0101, was studied for its immunosuppressive effects in both commercial broilers and SPF white Leghorn chickens infected at 1 day of age. Our data demonstrated that NX0101 induced much more significant body and immune organ weight loss in the infected commercial broiler chickens in an earlier age than that in the SPF white Leghorn chickens. At the same time antibody responses to vaccinations of Newcastle disease virus (NDV) and infectious bursa disease virus (IBDV) in the NX0101-infected chickens were also evaluated and compared between the commercial broiler chickens and the SPF white Leghorn chickens. Compared with the control group of chickens, the hemagglutination inhibition (HI) antibody response to NDV vaccines was significantly reduced in the NX0101-infected commercial broiler chickens from as early as 20 days after vaccination. However, no significant difference in HI antibody response was seen when HI titers reached their peaks in the NX0101-inoculated and control SPF white Leghorn chickens, except it declined significantly faster in infected birds. Neither of these two types of chickens showed significant decrease of antibody response to IBDV vaccination. Herein, we conclude that this NX0101 strain of ALV-J could selectively suppress humoral immune reactions to NDV, especially in broilers. But challenge experiments were not conducted and, therefore, it cannot be known if decreased antibody levels correlated with decreased protection against NDV in this case.     

新城疫单抗ELISA试剂盒监测免疫鸡群中新城疫强毒

应用新城疫（ND）单抗ELISA试剂盒对2个免疫鸡群中ND强毒感染情况及个体感染强毒后排毒动态跟踪监测，并平等测定其HI抗体效价。共采集泄殖腔棉拭子和血液对应样品2317份。结果表明：HI效价2－14之间的个体均可检出强毒，其中HI效价在6以下和11以上的个体强毒检出率都较高。HI效价在6以上的个体仍角感染强毒，强毒感染导致HI抗体水平上升，且感染前低者上升速度较快，幅度亦较大；并且发现排毒个体的高水平抗体是强毒感染所致。个体感染强毒后排毒过程可长达3周，而且感染前抗体水平低者排毒时间相对较长。强毒一旦侵入鸡群便可在群内巡回传播，长期维持下来。     

Oral vaccination of chickens against Newcastle disease with I-2 vaccine coated on oiled rice

Antibody response produced by Newcastle disease virus (NDV, strain I-2) when given orally through oiled rice to chickens was determined. Serum samples were collected before and at a weekly interval for 28 days after vaccination and tested for haemagglutination inhibition (HI) antibody to NDV. The results showed 7 days after vaccination HI antibody titre log₂ was 3.8. Moreover, 14 and 28 days after vaccination HI antibody titre log₂ reached 6.5 and 8.0, respectively. All unvaccinated chickens were negative to NDV antibody throughout the study. Significant finding from the present study is that 7 days after vaccination chickens had produced protective antibody against NDV; this is in contrast to previous studies. Therefore, I-2 vaccine coated on the oiled rice is efficacious as it protects chickens from challenge with NDV. Wambura, P. N., 2008. Oral vaccination of chickens against Newcastle disease with I-2 vaccine coated on oiled rice. Tropical Animal Health and Production.     

SIMULATED NATURAL INFECTION OF CHICKENS WITH AUSTRALIAN LENTOGENIC NEWCASTLE DISEASE VIRUS AND SUBSEQUENT CHALLENGE WITH VIRULENT VIRUS

A total of 291 eight-week-old chickens were exposed to chickens infected with either of two Australian lentogenic strains (V4 and AVL NDV-1) of Newcastle disease virus (NDV). At 3 weeks after exposure, all chickens exposed to V4 infected chickens had developed haemagglutination-inhibition (HI) antibody. All chickens exposed to AVL NDV-1 virus infected chickens had developed HI antibody 5 weeks later. This sudden late appearance of HI antibody, to titres higher than those observed with V4 chickens, was explained by V4 virus being introduced to the AVL NDV-1 group of chickens. When groups of these chickens were challenged with Roakin virus (mesogenic NDV) at 3 weeks and Fontana 1083 virus (viscerotropic velogenic NDV) and Texas GB virus (neutrotropic NDV) at 3, 5, 10 and 21 weeks only three chickens developed clinical illness one of which died. These chickens were one AVL NDV-1 chicken contact challenged with Fontana 1083 virus at 3 weeks, one V4 chicken oronasally challenged with Texas GB virus at 5 weeks and one V4 chicken challenged oronasally with Fontana 1083 virus at 10 weeks. Susceptible non-vaccinated chickens died soon after challenge. Challenge by oronasal infection with 10(7.0) ELD50 of virus or contact with susceptible infected chickens enabled virulent virus to be isolated from most chickens and was accompanied by a large anamnestic increase in serum HI antibody.     

CAV与REV共感染SPF鸡对疫苗免疫反应的抑制作用

用1日龄SPF鸡人工感染鸡贫血病毒(CAV)和禽网状内皮增生病病毒(REV),探讨病毒感染对鸡体疫苗免疫反应的影响。结果表明,在用禽流感病毒(AIV,H5和H9)疫苗免疫后,CAV与REV单独感染均显著抑制了鸡体对H5和H9亚型禽流感病毒灭活疫苗的HI抗体反应,在CAV与REV共感染后,这种抑制作用更为明显。CAV单独感染后鸡体对新城疫病毒(NDV)和传染性法氏囊病病毒(IBDV)疫苗的免疫反应受到抑制,但与对照组在统计学上的差异不显著,然而,CAV可以显著加重REV感染对鸡体在NDV和IBDV疫苗免疫后抗体反应的抑制作用。从而证实CAV与REV共感染在疫苗免疫抑制上有协同作用。     

山东省新城疫病毒的分离、鉴定及其毒力测定

在山东多个疑似新城疫的鸡群中,分离到13株具有血凝性的病毒,与多种阳性血清进行血凝抑制交叉试验,确定11株分离株均为新城疫病毒。为评价ND分离株的致病特性,对此11株病毒的毒力进行了测定,具体包括1日龄雏鸡脑内接种致病指数(ICPI)、6周龄雏鸡静脉内接种致病指数(IVPI)和最低致死量致死鸡胚的平均死亡时间(MDT),结果表明:这些分离株均为新城疫强毒株。     

新城疫CHR株与La Sota株2种疫苗近期免疫效力比较试验

鸡新城疫CHR 株冻干疫苗中试产品3 批以及La Sota 株冻干疫苗( 符合质量要求) , 以5 种免疫途径: 肌注、滴鼻、喷雾、饮水、拌料分别接种11 日龄雏鸡。每批疫苗每种途径接种1 组, 20 只/ 组, 共20 组。雏鸡群免疫前血凝抑制抗体(HI) 效价为1∶2-13 , 于14 d 、28 d 后再测HI抗体水平, 并分别用10 000 鸡胚半数致死量(ELD50) 新城疫标准强毒北京株攻击。从而检测2 种疫苗用5 种免疫途径免疫后在不同时间的近期免疫效力。结果表明, 近期内CHR 株疫苗HI抗体呈上升趋势, 而La Sota 株疫苗HI抗体先升高后下降; CHR 株疫苗以饮水和拌料途径效果较好, 其它3 种途径效果相似。接种后14 d 攻毒, 2 种疫苗均能较好保护强毒攻击; 28 d 后, CHR 株保护率高于La Sota 株。     

Experimental trials with a thermostable Newcastle disease virus (strain I2) in commercial and village chickens in Tanzania

Antibody responses in indigenous village and commercial chickens vaccinated with 12 thermostable Newcastle disease (ND) vaccine and protection levels against challenge with a virulent field isolate were determined. The antibody response of village chickens vaccinated by eye drop revealed that 30, 60 and 90 days after primary vaccination, the mean log2 HI titres were 6.1, 5.4 and 3.6, respectively, whereas for commercial chickens, the antibody response after 14, 30 and 90 days were 8.2, 5.1 and 4.2, respectively. Village chickens vaccinated orally via drinking water had mean log2 HI titres of 3.4 after 30 days. After booster vaccination, the mean HI titre was 5.4 and 3.3 after 30 and 60 days post-secondary vaccination (i.e. 60 and 90 days after primary vaccination). Antibody response of mean log2 HI titres of 2.6 was recorded 30 days after primary vaccination orally through food; 30 and 60 days after secondary vaccination (i.e. 60 and 90 days after primary vaccination), mean log2 HI titres were 5.3 and 3.2, respectively. All commercial and village chickens vaccinated by eye drop survived the challenge trial whereas village chickens vaccinated through drinking water and food had protection levels of 80% and 60% 30 days after primary vaccination, respectively. However, 30 days after booster vaccination, the protection level was 100%. At 60 days after secondary vaccination, the protection level dropped again to 80% for chickens vaccinated orally. All control chickens used in the challenge trials developed clinical ND and died 3-5 days after inoculation with the virulent virus. Supported by laboratory findings, I2 strain of NDV seemed to be avirulent, immunogenic and highly protective against virulent isolates of NDV. It may be a suitable vaccine to use in village chickens to vaccinate them against ND in rural areas.     

Humoral and cell-mediated immune responses in chickens with infectious bursal disease

Primary and secondary immune responses to Newcastle disease virus (NDV) was evaluated in chickens infected with infectious bursal disease virus (IBDV) at one and 28 days of age. The geometric mean primary hemagglutination-inhibition antibody titers (GMT) of chickens infected with IBDV at one day of age was significantly lower (P less than or equal to 0.01) than those infected at 28 days of age. Infection with IBDV had no influence on secondary immune response to NDV. The effect of IBDV infection at one day of age on the cell-mediated immunity of chickens was evaluated by skin allograft acceptance or survival time. There was no significant difference between the percentage of grafts accepted in IBDV infected and noninfected control chickens. However, the mean graft survival time in the IBDV infected chickens was significantly longer (P less than or equal to 0.05) than those in the control group. This suggested a suppression of cell-mediated immunity due to IBDV infection.     

A preliminary study of the role of ducks in the transmission of Newcastle disease virus to in-contact rural free-range chickens

The role of ducks in the transmission of Newcastle disease virus (NDV) to free-range village chicken was investigated experimentally. Newcastle disease (ND) seronegative ducklings reared in a pen were infected oronasally with velogenic NDV of intracerebral pathogenicity index (ICPI) 1.8 isolated from outbreaks in village chickens in Uganda. A first group of 3-week-old ND seronegative chicks was mixed with the ducks and they were kept together for 7 days. Both ducks and chicks were observed for ND clinical signs and any mortality, and they were bled and their sera were tested for ND antibodies by haemagglutination inhibition (HI) test. The chicks were removed, euthanized and examined for any ND lesions, while the ducks were transferred to a fresh pen and a second group of chicks was introduced and observed and treated as above. The ducks and the chicks tested positive for ND antibodies 7 days post infection and contact, respectively, but showed no clinical signs, post-mortem lesions or mortality. The mean ND antibody titre of the second group of chicks was lower than for the first group. This study has shown that although ducks can be infected with velogenic NDV, they do not show clinical signs but are able to transmit NDV to in-contact chicks. Further investigations are needed of the lack of clinical signs in the in-contact chicks and how long the ducks remain infective.     

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)     

新城疫病毒HI抗体效价与流行株感染排毒之间的相关性

为了分析免疫鸡群中新城疫强毒感染流行的原因,明确抗体效价与流行株感染排毒率之间的关系,本研究以LaSota为抗原制备新城疫灭活疫苗,并以0.02mL和0.4mL的量分别免疫3周龄的SPF鸡10只。免疫后7、14、21d分别测定免疫鸡血清中的抗体HI效价。免疫后21d以基因Ⅶd亚型新城疫流行株JS5/05进行攻毒,攻毒后每天观察试验鸡的临床症状,并于攻毒后3、5、7d采集试验鸡的喉气管与泄殖腔棉拭样品进行病毒分离,结果显示,免疫3周后0.02mL和0.4mL疫苗免疫组鸡的血清HI抗体平均效价分别为5.4log2和8.2log2;0.02mL免疫组在攻毒后的排毒率达到100%,且排毒时间较长,而0.4mL免疫组在攻毒后的排毒率明显降低,且排毒时间较短。上述结果表明新城疫抗体效价与流行株感染排毒率之间存在明显的负相关。     

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     

Resistance of chickens to challenge with the virulent Herts 33 strain of Newcastle disease virus induced by prior infection with serologically distinct avian paramyxoviruses.

Results indicate that some degree of protection from challenge by Newcastle disease virus (NDV)/Herts 33 was conferred on chickens by prior infection with PMV/turkey/Wisconsin/68, PMV/turkey/Ontario/6661/68, PMV/Netherlands/449/75 and PMV/parakeet/England/39/78 viruses, all of which are serologically related but distinguishable from NDV. Except for one bird which survived challenge three weeks after infection with Robin/Hiddensee/19/75, no protection was seen in chickens infected with other unrelated avian paramyxoviruses. In contrast to infection with NDV-B1, birds protected by infection with avian paramyxoviruses showed large increases in NDV haemagglutination inhibition (HI) titres after challenge. In these birds considerable increases in the homologous HI titres were also seen after challenge.     

免疫蛋鸡携带新城疫病毒的调查研究

实验对江苏省某地区 2 2个免疫鸡场进行了新城疫病毒抗体随机抽样监测 ;并从所抽样的鸡只中无菌采集气管及泄殖腔棉拭子样品 ,接种非免疫鸡胚进行病毒分离与鉴定。结果表明 ,在不同新城疫病毒抗体水平的鸡群 ,均可分离到新城疫病毒 ;这提示了新城疫病毒抗体水平只能用于衡量机体的体液免疫状况 ,而不能作为评价鸡群是否带毒的指标     

企鹅新城疫强毒的分离鉴定

从某动物园送诊的病死小企鹅肝脏分离到一株病毒,经血凝抑制试验（ＨＩ）和电镜观察确定为新城疫病毒。采用ＳＰＦ鸡胚和ＳＰＦ鸡测定其致病指数分别为：ＭＤＴ＝６２．１小时,ＩＣＰＩ＝２．４８,ＩＶＰＩ＝１．６７,属于强毒株。动物病试验表明该毒株经滴鼻／点眼途径可在９６小时内致死６周龄ＳＰＦ鸡,并出现典型的新城疫症状和病变。初步试验表明经静脉注射途径可致死７日龄北京雏鸭。     

鸡新城疫重组鸡痘病毒活疫苗的免疫持续期和加强免疫研究

本研究旨在评价表达新城疫病毒（NDV）血凝素-神经氨酸酶（HN）基因的重组鸡痘病毒（rFPV-12LSHN）活疫苗的免疫持续期和加强免疫对疫苗免疫效力的影响。用rFPV-12LSHN活疫苗免疫14日龄SPF鸡,103PFU/羽,7d即可检测到NDV HI抗体应答,对NDV强毒F48E8株攻毒保护率达100%。一次免疫18周后,对NDV强毒攻击依然提供完全保护。鸡痘病毒（FPV）疫苗免疫4周,再接种rFPV-12LSHN活疫苗,攻毒保护率降低至50%。相反,rFPV-12LSHN免疫4周,随后二次免疫可显著提高对NDV的体液免疫应答水平（P〈0.01）,对NDV强毒攻击的保护率仍然为100%。结果表明,表达NDV HN基因的重组鸡痘病毒（rFPV-12LSHN）活疫苗,能够快速建立坚强免疫力,免疫持续期至少可达18周,rFPV-12LSHN的二次免疫可以提高疫苗的免疫力。     

新城疫La Sota疫苗对山东分离株的免疫保护试验

用标准疫苗株La Sota活疫苗在隔离器中接种SPF鸡,进行免疫保护试验.免疫后,每7 d采血监测NDV抗体,免疫后2周,利用经过鉴定的新城疫病毒(NDV)潍坊毒SGM01、昌乐毒SCL03、东营毒HY、日照毒SRZ03、莘县毒SSX03和标准强度F48E9分别进行攻毒试验,同时设SPF鸡对照.每天观察,及时剖检发病鸡,检查鸡群病变,确定疫苗的保护性.结果表明,La Sota疫苗能对除SGM01和HY以外的病毒攻击的SPF鸡提供较好的保护.     

Protection levels of vaccinated pigeons (<Emphasis Type="Italic">Columba livia)</Emphasis> against a highly pathogenic newcastle disease virus strain

The purposes of this study were to model a vaccination regimen for Newcastle disease virus (NDV) in pigeons, and to evaluate the susceptibility and behavior of vaccinated birds against a highly pathogenic NDV Brazilian strain. Antibody response was assessed by means of hemagglutination inhibition test (HI), and viral genome excretion by means of RT-PCR. Vaccinal strains (La Sota and Ulster) induced high antibody titers without any adverse effects, both in inoculated and in sentinel birds. A viral strain pathogenic for chickens did not produce clinical signs of the disease in experimentally infected pigeons. Only 4 out of 10 vaccinated pigeons shed NDV genome, and just for two days. Results confirmed the high infectivity of the vaccinal strains used, as all nonvaccinated pigeons showed antibody titers as high as those of vaccinated birds.