Protection conferred by vaccination with Blacksburg and Komarov strains of Newcastle disease virus against Newcastle disease in Bangladesh

Summary An evaluation was undertaken of the efficacy of vaccination of day-old chicks with the Blacksburg (B1) strain of Newcastle disease virus (NDV) followed at various times by vaccination with the Komarov (K) strain. Antibody was detected by the haemagglutination inhibition (HAI) test one week after vaccination with B1 and titres peaked at three weeks and had declined to undetectable levels by nine weeks.After subsequent vaccination with K strain at five, seven or eight weeks of age levels of HAI antibody (titre 80 to 640) were detected after three weeks. Birds vaccinated at seven weeks were tested for antibody and resistance to challenge beyond 19 weeks of age. In this group the HAI titres remained constant (80 to 640) up to 32 weeks of age and then steadily declined to 10 to 20 at 44 weeks of age.A linear relationship between HAI titre and virus neutralising index (VNI) was demonstrated with a range of selected sera. Only birds with an HAI titre of 80 or greater resisted artificial challenge. It is recommended that, following B1 vaccincation at day-old and K vaccination at seven weeks old, revaccination with K strain should be performed at intervals of not more than seven months.

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Proteccion Conferida Mediante Vacunacion Con Las Cepas Blacksburg Komarov Del Virus De Newcastle En Bangladesh

Resumen Se llevó a cabo una evaluación de la eficacia de la vacunación de pollitos de un día, con la cepa Blacksburg (B1) del virus de la enfermedad de Newcastle, seguida de varias aplicaciones vacunales periódicas con la cepa Komarov (K). Se detectaron anticuerpos mediante la prueba de inhibición de la hemaglutinación, una semana después de la vacunación con B1, los títulos alcanzando el pico a las tres semanas y declinaron a niveles no detectables a las nueve semanas.Después de aplicaciones vacunales periódicas con la cepa K, a las cinco, siete u ocho semanas de edad, se detectaron anticuerpos mediante la prueba de inhibición de la hemaglutinación (títulos 80 a 640), después de tres semanas. Las aves vacunadas a las siete semanas, recibieron una descarga y se les hizo prueba de anticuerpos, después de las 19 semanas de edad. En este grupo los títulos de anticuerpos permanecieron constantes (80 to 640) hasta las 32 semanas de edad y después declinaron lentamente a 10 ó 20 a las 44 semanas de edad.Se demostró una relación lineal entre los títulos hallados y el índice viral neutralizante, en un rango de sueros seleccionados. Solamente las aves con títulos de 80 o más altos resistieron la descarga artificial. Se recomienda que, seguidamente a la vacunación con B1 a un día de edad y con K a las siete semanas, las revacunaciones con la cepa K debería hacerse con intervalos de no más de siete meses.

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Protection Conferee Contre La Maladie De Newcastle Au Bangladesh Par La Vaccination A L'Aide Des Souches Blacksburg Et Komarov De Virus De La Maladie De Newcastle

Résumé Une evaluation de l'efficacité de la vaccination de poussins d'un jour à l'aide des souches Blackburg (B1) du virus de la maladie de Newcastle, suivie à différents moments par la vaccination à l'aide de la souche Komarov (K), a été entreprise. Les anticorps furent détéctés par inhibition de l'hemagglutination (HAI), une semaine après la vaccination avec la souche B1 et le titre atteignit un pic à 3 semaines pour décliner jusqu'à des niveaux indétectables à neuf semaines. A la suite de vaccinations consécutives avec la souche K à cinq, sept ou huit semaines, les niveaux d'anticorps HAI furent détectés après trois semaines. Les oiseaux vaccinés à sept semaines furent examinés pour les anticorps et la résistance à une épreuve au delà de 19 semaines d'âge. Dans ce groupe les titres HAI sont restés constants (80 à 640) jusqu'à l'àge 32 semaines, puis ont diminué régulièrement jusqu'à 10 à 20 à l'âge de 44 semaines.Une relation linéaire entre le titre HAI et l'index de neutralisation du virus (VNI) a été démontrée sur une gamme de sérums choisis. Seuls les oiseaux ayant un titre HAI de 80 ou plus ont résisté à l'épreuve artificielle. On recommande que, après une vaccination B1 à un jour, et une vaccination K à l'âge de sept semaines, une revaccination K soit réalisée à des intervalles n'excédant pas sept mois.

     

Vaccination against Moroccan strains of Newcastle disease virus

Summary Different vaccination programmes commonly used in Moroccan poultry farms were tested for their capacity to protect chickens against two representative Moroccan strains of velogenic viscerotropic Newcastle disease virus under controlled conditions. All vaccination programmes protected the chickens against mortality and the inactivated vaccine gave the highest antibody titres and the best protection against respiratory symptoms.

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Vacunacion Contra Cepas Marroquies Del Virus De La Enfermedad De Newcastle

Resumen Se ensayaron bajo condiciones controladas, diferentes programas de vacunación para detectar la capacidad de estos de proteger pollos contra dos cepas marroquíes representativas del virus velogénico viscerotrópico de la enfermedad de Newcastle. Todos los programas de vacunación fueron efectivos, protegiendo las aves contra mortalidad. La vacuna inactivada fue la mejor, produciendo los títulos más altos de anticuerpos y protegiendo las aves contra síntomas respiratorios.

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Vaccination Contre Les Souches Marocaines Du Virus De La Maladie De Newcastle

Résumé On a testé différents programmes de vaccination communément mis en oeuvre dans les élevages avicoles du Maroc quant à leur capacité de protéger les poulets vis-à-vis de deux souches marocaines représentatives du virus de Newcastle vélogène-viscérotrope. Les poulets ont été protégés dans tous les programmes de vaccination à l'encontre de la mortalité; le vaccin inactivé confère les plus hauts titres en anticorps et la meilleure protection vis-à-vis des symptômes respiratoires.

     

Vaccination of cyclophosphamide-treated chickens against Newcastle disease virus infection

Newly-hatched chickens were treated with 3 mg of cyclophosphamide (CY) per day for 4 consecutive days. At 2 weeks of age, these chickens, together with a group of untreated controls, were vaccinated intranasally or subcutaneously with the La Sota strain of Newcastle disease virus (NDV). All chickens were challenged intranasally with the GB strain of NDV 2 weeks later. CY-treated, intranasally vaccinated chickens were highly resistant to NDV challenge, yet none of the chickens produced any detectable humoral antibodies to NDV; antibodies to NDV were detectable in the tracheal washings, however.     

Efficacy of a commercial Newcastle vaccine against velogenic viscerotropic Newcastle disease virus.

Effects of parental immunity and method of vaccination were studied in broiler chickens vaccinated with a commercial LaSota vaccine and challenged with the Fontana strain of velogenic viscerotropic Newcastle disease (VVND). Immunity was satisfactory from all methods of vaccination used.     

Protective immunity against Newcastle disease: the role of antibodies specific to Newcastle disease virus polypeptides

Studies were performed to determine if passive immunization with hyperimmune sera generated to specific Newcastle disease virus (NDV) proteins conferred protection against virus challenge. Six groups of 3-wk-old chickens were passively immunized with antiserum against either hemagglutinin-neuraminidase/fusion, (HN/F) protein, nucleoprotein/phosphoprotein (NP/P), Matrix (M) protein, a mixture of all NDV proteins (ALL), intact ultraviolet-inactivated NDV (UVNDV), or negative sera. Blood samples were collected 2 days postimmunization, and the birds were challenged with Texas GB strain of NDV. Antibody titers were detected from those recipient birds that had received the antisera against the HN/F, ALL, or UVNDV by a hemagglutination inhibition test, an enzyme-linked immunosorbent assay (ELISA), and a virus neutralization test. Antibodies were detected only by the ELISA from the birds that had received antisera against NP/P and M protein. Antibody titers in the recipient birds dropped by two dilutions (log2) after 2 days postinjection. Birds passively immunized with antisera against HN/F, ALL, and UVNDV were protected from challenge, whereas chickens passively immunized with antisera against NP/P and M protein and specific-pathogen-free sera developed clinical signs of Newcastle disease. The challenge virus was recovered from the tracheas of all passively immunized groups. The presence of neutralizing antibodies to NDV provided protection from clinical disease but was unable to prevent virus shedding from the trachea.     

米糠凝集素的部分特性及其抗新城疫病毒作用

采用红细胞凝集试验和观察细胞病变（CPE）的方法分别研究了米糠凝集素的特性和抗病毒作用。结果显示,米糠凝集素能凝集鸡红细胞,促进新城疫病毒对红细胞的凝集,对热有一定的稳定性,耐酸碱;在体外,用米糠凝集素与新城疫病毒作用或用米糠凝集素预处理Vero细胞,均能抑制新城疫病毒在细胞上病变的形成。提示,米糠凝集素具有直接抗新城疫病毒和预防新城疫病毒感染的作用。     

新城疫病毒通用型实时RT-PCR检测方法的建立与应用

采用TaqMan方法,经引物和探针的设计、筛选及反应条件优化,研究了检测活禽和禽产品中新城疫病毒的通用型实时RT-PCR(RRT-PCR)方法。结果显示,对12株分别为速发型、中发型、缓发型和疫苗株新城疫病毒的尿囊液倍比稀释液的检测极限在10-5~10-7之间;建立的方法与常见禽类病毒无交叉反应,特异性良好;在检测人工感染肉鸡的脏器组织、咽喉、泄殖腔拭子中病毒的灵敏度同鸡胚分离试验基本一致;弱毒疫苗免疫鸡群在免疫后14 d,应用本方法不能从咽喉、泄殖腔拭子中检测到病毒;临床样品检测表明,该方法不仅可以检出中强毒力新城疫毒株,也可检出缓发型野毒株和疫苗毒株。     

Protective efficacy of commercial Newcastle disease vaccines against challenge of goose origin virulent Newcastle disease virus in geese

Since 1997, severe outbreaks of Newcastle disease (ND) in geese in many regions throughout China have resulted in high morbidity and mortality, and great economic loss to farmers; however, no licensed, specific vaccine is yet available for this disease in China. In this study, goslings were immunized with different combinations and dosages of several commercial ND vaccines including La Sota vaccine, Mukteswar vaccine, recombinant live vaccine against avian influenza (AI) and ND (rL-H5 strain), and inactivated ND oil-emulsion vaccine (La Sota strain). The protective effects were evaluated based upon the level of antibody response and the degree of protection against the goose-origin virulent NDV strain. The result showed that two doses (i.e., one more than that for chicken) of La Sota vaccine priming, followed by 2-5 doses of Mukteswar vaccine boosting 2-3 weeks later, not only induced higher HI antibody levels, but also conferred longer-lasting protection. This immunization procedure can be recommended for prevention of ND in geese.     

不同新城疫弱毒苗对新城疫病毒强毒的免疫保护试验

用NDV的LaSota株、VG/GA 株、VH 株、PHY LMV 42株及Clone 30株弱毒疫苗免疫SPF鸡后 ,通过对雏鸡免疫后的血清抗体监测表明 ,4种弱毒疫苗激发雏鸡的抗新城疫病毒抗体滴度在 7log2水平以下 ,且差异不显著。通过以上 4种新城疫弱毒疫苗对新城疫病毒东台强毒株的免疫保护试验表明 :至少单独使用弱毒疫苗 ,不能对东台地区流行的新城疫病毒强毒株提供有效保护 ,保护率在 60 %～ 74%     

BHK-21细胞无血清悬浮培养生产新城疫病毒

为建立基于无血清悬浮培养细胞生产新城疫病毒(NDV)的工艺,本研究首先筛选了适于NDV增殖的乳仓鼠肾细胞(BHK-21)单克隆细胞株,并将鸡胚适应的NDV在筛选获得的细胞株(BHK-v002)中传代,获得细胞适应的NDV。进一步采用单因素实验法检测病毒感染复数(MOI)、TPCK-胰酶浓度、细胞培养液的稀释比例等工艺参数对病毒效价的影响。结果显示,NDV在无血清培养的BHK-v002细胞中增殖的最适条件为:当细胞生长至约9.0×10^6个/mL时,以培养液.新鲜培养基为2:1的比例补加新鲜培养基,使细胞密度达6.0×10^6个/m L,按MOI为0.005接种NDV LaSota株,TPCK-胰酶终浓度为5μg/mL。接种病毒后96 h收获病毒液的HA效价为8.5 log2HAU/25μL,单细胞产毒量(Svy)达到1 685.9病毒颗粒/细胞,半数组织细胞感染剂量(TCID50)为7.9 log10TCID50/100μL。本研究确定了NDV LaSota株在BHK-21细胞悬浮培养中的增殖条件,建立了基于BHK-21细胞无血清悬浮培养体系中NDV的生产工艺,该工艺操作简便,易于放大,为当前ND疫苗的鸡胚生产工艺提供了候选替代方案。     

Vaccination with Newcastle disease vaccine and CpG oligodeoxynucleotides induces specific immunity and protection against Newcastle disease virus in SPF chicken

Oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODN) have been proven to be immunoprotective in mouse models. However, little work has been conducted on in vivo immune responses in chicken with CpG ODN. The objective of this study was to investigate the immunoadjuvant effects of CpG ODN to Newcastle disease (ND) vaccine and its protective effects against ND virus in SPF chicken. In this report, the titre of serum IgG to ND vaccine and the proliferation of lymphocytes were monitored in SPF chickens. The results demonstrated that the above-mentioned immune responses were significantly stronger in chickens that received CpG ODN than in the birds that received only ND vaccine. Furthermore, ND vaccine plus CpG ODN protected SPF chicken from challenge with an otherwise lethal dose of ND virus. These data suggest that CpG ODN holds considerable promise as an adjuvant for future vaccines against ND virus.     

鸡体内鹅源新城疫病毒抗原的免疫组织化学检测

为研究鹅新城疫（ND）的发病机理,用3株鹅新城疫病毒强毒株分别人工感染25日龄雏鸡,以单克隆抗体介导的免疫组化（IHC）法检测攻毒鸡体内NDV抗原的分布及定位,研究了鹅新城疫病毒（NDV）对鸡的组织嗜性。结果显示。在试验鸡多种组织器官中均能检测到NDV抗原,病毒抗原主要定位于淋巴细胞、网状细胞、巨噬细胞、肝细胞及各种上皮细胞的胞浆内。结果表明,鹅NDV强毒株对鸡是一种泛嗜性病毒。     

Checking of immunity against Newcastle disease by ELISA.

A total of 284 seven- to twelve-week-old Tetra SL chickens were assigned to 18 groups and immunized with a full or fractional dose of monovalent or multivalent inactivated vaccines subcutaneously or intramuscularly. Sera were taken from the birds at the time of challenge and tested for antibodies to Newcastle disease virus (NDV) by enzyme-linked immunosorbent assay (ELISA). The vaccinated birds were challenged with 10(6) ELD50 of virulent NDV subcutaneously. A close positive correlation (r = 0.954) was found between the protection percentage of the different groups and the group's arithmetical mean net extinction percentage (NE%) calculated from the net extinction values obtained for sera of birds belonging to the given group. NE% is easy to calculate and a good indicator of the flocks' immunity status. In our case: if NE% exceeded 80, the protection percentage of the flock was between 93.3 and 100%; if NE% was between 60 and 80, the protection percentage was between 75 and 87%, while with an NE% less than 60 the protection percentage ranged between 6.7 and 64.3%.