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1.
Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.  相似文献   

2.
Hu Z  Hu S  Meng C  Wang X  Zhu J  Liu X 《Avian diseases》2011,55(3):391-397
To generate a genotype VII Newcastle disease virus (NDV) vaccine with high yield in embryonated chicken eggs, we selected genotype VII NDV strain JS5/05, which possesses a high virus titer in embryos as the parental virus. Using reverse genetics, we generated a genetically tagged derivative (NDV/AI4) of JS5/05 by changing the amino acid sequence of the cleavage site of the F0 protein. Pathogenicity tests showed that NDV/AI4 was completely avirulent. NDV/AI4 was genetically stable and replicated efficiently during 10 consecutive passages in embryos. More importantly, serologic assays showed that oil-emulsion NDV/AI4 induced higher hemagglutination inhibition (HI) titers against the prevalent virus than oil-emulsion LaSota vaccine in chickens and geese. Moreover, NDV/AI4-induced HI titers rose faster than those elicited by LaSota in chickens. Both NDV/AI4 and LaSota provided protection against clinical disease and mortality after the challenge with the genotype VII NDV strain JS3/05. However, NDV/AI4 significantly reduced virus shedding from the vaccinated birds compared to LaSota. Taken together, these results suggest that NDV/AI4 can provide better protection than LaSota and is a promising vaccine candidate against genotype VII NDV.  相似文献   

3.
Newcastle disease (ND) is a highly contagious disease of chickens causing significant economic losses worldwide. Due to the limitation in their efficacy, current vaccination strategies against ND need improvements. This study aimed to evaluate a new-generation ND vaccine for its efficacy in providing clinical protection and reducing virus shedding after challenge. Broiler chickens were vaccinated in ovo or subcutaneously at hatch with a turkey herpesvirus-based recombinant vaccine (rHVT) expressing a key protective antigen (F glycoprotein) of Newcastle disease virus (NDV). Groups of birds were challenged at 20, 27, and 40 days of age with a genotype V viscerotropic velogenic NDV strain. Protection was 57% and 81%, 100% and 95%, and 100% and 100% after the subsequent challenges in the in ovo and subcutaneously vaccinated chickens, respectively. Humoral immune response to vaccination could be detected from 3-4 wk of age. Challenge virus shedding was lower and gradually decreased over time in the vaccinated birds compared to the unvaccinated control chickens. In spite of the phylogenetic distance between the NDV F gene inserted into the vector vaccine and the challenge virus (genotype I and V, respectively), the rHVT NDV vaccine provided good clinical protection and significantly reduced challenge virus shedding.  相似文献   

4.
Recently, genotype VII of Newcastle disease virus (NDV) has become the most prevalent NDV genotype in Asia. Here the hemagglutinin-neuraminidase (HN) gene of genotype VII NDV strains isolated in Japan was analyzed. Notably, point amino acid substitutions in the HN protein at position 347, which is located on the major linear epitope of the HN protein, were found in two strains. However, by a hemagglutination inhibition assay, major antigenic differences did not exist between the studied strains. Additionally, chickens vaccinated with the B1 strain did not exhibit clinical effects after challenge with variants possessing the substitution at position 347 (E to K), whereas all unvaccinated chickens subjected to this challenge died within 5 days.  相似文献   

5.
Newcastle disease (ND) is one of the most important diseases of poultry, and may cause devastating losses in the poultry industry worldwide. Its causative agent is Newcastle disease virus (NDV), also known as avian paramyxovirus type 1. Many countries maintain a stringent vaccination policy against ND, but there are indications that ND outbreaks can still occur despite intensive vaccination. It has been argued that this may be due to antigenic divergence between the vaccine strains and circulating field strains. Here we present the complete genome sequence of a highly virulent genotype VII virus (NL/93) obtained from vaccinated poultry during an outbreak of ND in the Netherlands in 1992-1993. Using this strain, we investigated whether the identified genetic evolution of NDV is accompanied by antigenic evolution. In this study we show that a live vaccine that is antigenically adapted to match the genotype VII NL/93 outbreak strain does not provide increased protection compared to a classic genotype II live vaccine. When challenged with the NL/93 strain, chickens vaccinated with a classic vaccine were completely protected against clinical disease and mortality and virus shedding was significantly reduced, even with a supposedly suboptimal vaccine dose. These results suggest that it is not antigenic variation but rather poor flock immunity due to inadequate vaccination practices that may be responsible for outbreaks and spreading of virulent NDV field strains.  相似文献   

6.
从山东省发病鸡群分离鉴定了一株新城疫病毒(NDV),命名为SDLY01。经蚀斑纯化后进行毒力测定和序列分析表明分离株SDLY01属于基因Ⅶ型NDV强毒。20只7日龄SPF鸡免疫新城疫活疫苗LaSot a后14 d分别用NDV标准强毒F48E8和分离株SDLY01攻毒,同时设同日龄SPF鸡为对照组,未免疫任何疫苗。攻毒后观察10 d,免疫组在攻毒后食欲、精神均正常;对照组在攻毒后2～4d发病死亡,并表现ND典型的临床症状和病理变化。攻毒后第3、5、7、9 d对免疫组试验鸡取喉头、泄殖腔棉拭进行病毒分离,F48E8攻毒组病毒分离均为NDV阴性,SDLYO1攻毒组第5 d病毒分离NDV阳性,第3、7和9d病毒分离阴性。本研究结果表明LaSot a活疫苗对F48E8和SDLY01均能提供100%免疫保护,但不能完全抑制基因Ⅶ NDV分离株在体内的复制和排毒。  相似文献   

7.
The role of cell-mediated immunity (CMI) in protection of birds from Newcastle disease was investigated by two different strategies in which only Newcastle disease virus (NDV)-specific CMI was conveyed without neutralizing antibodies. In the first strategy, selected 3-wk-old specific-pathogen-free (SPF) birds were vaccinated with either live NDV (LNDV), ultraviolet-inactivated NDV (UVNDV), sodium dodecyl sulfate-treated NDV (SDSNDV), or phosphate-buffered saline (PBS) (negative control) by the subcutaneous route. Birds were booster vaccinated 2 wk later and challenged with the velogenic Texas GB strain of NDV 1 wk after booster. All vaccinated birds had specific CMI responses to NDV as measured by a blastogenesis microassay. NDV neutralizing (VN) and hemagglutination inhibition (HI) antibody responses were detected in birds vaccinated with LNDV and UVNDV. However, birds vaccinated with SDSNDV developed antibodies that were detected by western blot analysis but not by the VN or HI test. Protection from challenge was observed only in those birds that had VN or HI antibody response. That is, birds with demonstrable CMI and VN or HI antibody response were protected, whereas birds with demonstrable CMI but no VN or HI antibody response were not protected. In the second strategy, birds from SPF embryos were treated in ovo with cyclophosphamide (CY) to deplete immune cells. The birds were monitored and, at 2 wk of age, were selected for the presence of T-cell activity and the absence of B-cell activity. Birds that had a significant T-cell response, but not a B-cell response, were vaccinated with either LNDV, UVNDV, or PBS at 3 wk of age along with the corresponding CY-untreated control birds. The birds were booster vaccinated at 5 wk of age and were challenged with Texas GB strain of NDV at 6 wk of age. All birds vaccinated with LNDV or UVNDV had a specific CMI response to NDV, VN or HI NDV antibodies were detected in all CY-nontreated vaccinated birds and some of the CY-treated vaccinated birds that were found to have regenerated their B-cell function at 1 wk postbooster. The challenge results clearly revealed that CY-treated birds that had NDV-specific CMI and VN or HI antibody responses to LNDV or UVNDV were protected, as were the CY-nontreated vaccinated birds. However, birds that had NDV-specific CMI response but did not have VN or HI antibodies were not protected from challenge. The results from both strategies indicate that specific CMI to NDV by itself is not protective against virulent NDV challenge. The presence of VN or HI antibodies is necessary in providing protection from Newcastle disease.  相似文献   

8.
Recombinant strains of herpesvirus of turkeys (HVT) were constructed that contain either the fusion protein gene or the hemagglutinin-neuraminidase gene of Newcastle disease virus (NDV) inserted into a nonessential gene of HVT. Expression of the NDV antigens was regulated from a strong promoter element derived from the Rous sarcoma virus long terminal repeat. Recombinant HVT strains were stable and fully infectious in cell culture and in chickens. Chickens receiving a single intra-abdominal inoculation at 1 day of age with recombinant HVT expressing the NDV fusion protein had an immunological response and were protected (> 90%) against lethal intramuscular challenge at 28 days of age with the neurotropic velogenic NDV strain Texas GB. Recombinant HVT expressing the NDV hemagglutinin-neuraminidase provided partial protection (47%) against the same challenge. Chickens vaccinated with recombinant HVT vaccines had low levels of protection against NDV replication in the trachea when challenged ocularly. Recombinant HVT vaccines and the parent HVT strain provided similar levels of protection to chickens challenged with the very virulent RB1B strain of Marek's disease virus, indicating that insertion of foreign sequences into the HVT genome did not compromise the ability of HVT to protect against Marek's disease.  相似文献   

9.
King DJ 《Avian diseases》1999,43(4):745-755
Four-week-old specific-pathogen-free white rock chickens were immunized with either a commercial recombinant fowl poxvirus-vectored Newcastle disease vaccine (FPN) expressing the hemagglutinin-neuraminidase and fusion protein genes of Newcastle disease virus (NDV) strain B1 or live NDV B1. Vaccinates and controls were challenged by eyedrop and intranasal (E/I) route with a viscerotropic velogenic NDV at 14 days postvaccination to determine the time of clearance of challenge virus. In a subsequent experiment, chickens were challenged at 3, 6, or 10 days postvaccination to determine the onset of immunity. Chickens that received a recommended field dose (1x) or a 0.01x dose of FP-N subcutaneously (s.c.) and were seropositive by hemagglutination-inhibition test at 14 days postvaccination cleared the challenge virus by 14 days postchallenge. Clinical Newcastle disease and high challenge virus titers in tissues were seen only in seronegative FP-N 0.01x dose vaccinates and controls. In a comparison of vaccination with FP-N (1x, 10(4,9) median tissue culture infective dose) s.c., B1 (10(6) median egg infective dose [EID50]) s.c., or B1 (10(6) EID50) E/I, chickens vaccinated at 6 or 10 days before challenge with all vaccines were protected against clinical disease, but only those vaccinated with B1 E/I 10 days before challenge were protected against infection with the challenge virus. Vaccination at 3 days before challenge with B1 E/I provided early protection, but severe nervous signs developed later and reduced overall protection to 60%, whereas disease in chickens vaccinated with B1 s.c. and FP-N s.c. 3 days before challenge was similar to the challenge controls.  相似文献   

10.
将重组鸡痘病毒vFV282疫苗用生理盐水作10^-1，10^-2，10^-3，10^-4系列稀释，分别免疫7天龄鸡，于免疫后21d，分别用NDV、IBDV和FPV攻毒，观察其保护率，结果除NDV攻毒在10^-4组保护率为40％（4／10），其余各组均为100％（10／10）保护。表明该疫苗的最小免疫剂量≤10^-3TCID50/0.02mL。  相似文献   

11.
Sun HL  Wang YF  Tong GZ  Zhang PJ  Miao DY  Zhi HD  Wang M  Wang M 《Avian diseases》2008,52(1):111-117
A recombinant fowlpox virus (rFPV) coexpressing the Newcastle disease virus (NDV) fusion and hemagglutinin-neuraminidase genes and infectious laryngothracheitis virus (ILTV) glycoprotein B gene was constructed. This virus was then evaluated for its ability to protect specific-pathogen-free (SPF) chickens against clinical symptoms and death after challenge by virulent NDV and ILTV. SPF chickens were grouped and vaccinated with the rFPV and commercial NDV (La Sota) and ILTV attenuated live vaccine (Nobilis ILT), respectively. After challenge with NDV 10 days postvaccination, 70% of chickens vaccinated with rFPV were protected from death, whereas 100% of the commercial NDV-vaccinated chickens were protected from death. In contrast, 100% of the unvaccinated chickens died after challenge. After challenge with ILTV, both the rFPV and commercial ILTV-vaccinated chickens were completely protected from death and 70% of chickens were protected from respiratory signs. In comparison, 100% of the unvaccinated chickens developed severe respiratory disease and 10% of chickens died. The protective efficacy was also measured by the antibody responses and isolation of challenge viruses. Results showed that this rFPV could be a potential vaccine for preventing NDV and ILTV by a single immunization.  相似文献   

12.
Specific-pathogen free (SPF) chickens were inoculated with the plasmid constructs encoding the fusion (F) and haemagglutinin-neuraminidase (HN) glycoproteins of Newcastle disease virus (NDV), either individually or in combination and challenged with velogenic NDV. The antibody level against NDV was measured using commercial enzyme linked immunosorbent assay (ELISA). In the first immunization regimen, SPF chickens inoculated twice with NDV-F or NDV-HN constructs elicited antibody responses 1 week after the second injection. However, the levels of the antibody were low and did not confer significant protection from the lethal challenge. In addition, administration of the plasmid constructs with Freund's adjuvant did not improve the level of protection. In the second immunization regimen, chickens inoculated twice with the plasmid constructs emulsified with Freund's adjuvant induced significant antibody titers after the third injection. Three out of nine (33.3%) chickens vaccinated with pEGFP-HN, five of ten (50.0%) chickens vaccinated with pEGFP-F and nine of ten (90.0%) chickens vaccinated with combined pEGFP-F and pEGFP-HN were protected from the challenge. No significant differences in the levels of protection were observed when the chickens were vaccinated with linearized pEGFP-F. The results suggested that more than two injections with both F and HN encoding plasmid DNA were required to induce higher level of antibodies for protection against velogenic NDV in chickens.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
The efficacy of green-coloured (GC) I-2 Newcastle disease vaccine was determined in the present study. I-2 vaccine was mixed with a green coloured dye and stored at 4°C for 6 months while assayed for the virus infectivity at a monthly interval. Chickens were vaccinated with the GC vaccine by eye drop. Serum samples were collected from all birds before and after vaccination at weekly interval for 4 weeks and tested for haemagglutination-inhibition (HI) antibody against Newcastle disease virus (NDV). These chickens were challenged with NDV virulent strain four weeks after vaccination. The results showed that there was no difference between the infectivity titres of GC and uncoloured vaccines. However, chickens vaccinated with GC vaccine produced higher HI antibody titres than chickens vaccinated with uncoloured vaccine. Results from the challenge trial showed that all vaccinated chickens survived whereas all unvaccinated chickens died. The findings from this study have shown that the GC vaccine is safe and produced protective antibodies against NDV in vaccinated chickens. Wambura, P. N., 2008. Protective antibody response produced by the chickens vaccinated with green coloured thermostable Newcastle disease virus. Tropical Animal Health and Production.  相似文献   

16.
OBJECTIVE: To evaluate the vaccine efficacy of a fowlpox virus recombinant expressing the H7 haemagglutinin of avian influenza virus in poultry. PROCEDURE: Specific-pathogen-free poultry were vaccinated with fowlpox recombinants expressing H7 or H1 haemagglutinins of influenza virus. Chickens were vaccinated at 2 or 7 days of age and challenged with virulent Australian avian influenza virus at 10 and 21 days later, respectively. Morbidity and mortality, body weight change and the development of immune responses to influenza haemagglutinin and nucleoprotein were recorded. RESULTS: Vaccination of poultry with fowlpox H7 avian influenza virus recombinants induced protective immune responses. All chickens vaccinated at 7 days of age and challenged 21 days later were protected from death. Few clinical signs of infection developed. In contrast, unvaccinated or chickens vaccinated with a non-recombinant fowlpox or a fowlpox expressing the H1 haemagglutinin of human influenza were highly susceptible to avian influenza. All those chickens died within 72 h of challenge. In younger chickens, vaccinated at 2 days of age and challenged 10 days later the protection was lower with 80% of chickens protected from death. Chickens surviving vaccination and challenge had high antibody responses to haemagglutinin and primary antibody responses to nucleoprotein suggesting that although vaccination protected substantially against disease it failed to completely prevent replication of the challenge avian influenza virus. CONCLUSION: Vaccination of chickens with fowlpox virus expressing the avian influenza H7 haemagglutinin provided good protection against experimental challenge with virulent avian influenza of H7 type. Although eradication will remain the method of first choice for control of avian influenza, in the circumstances of a continuing and widespread outbreak the availability of vaccines based upon fowlpox recombinants provides an additional method for disease control.  相似文献   

17.
The German Regulation on Fowl plague which is in force since 1994 laid down that any chicken of all races and all hybrids must be vaccinated against Newcastle disease (ND) in a mode that an adequate immunity is achieved. Onset, duration, and resistance to challenge of immunity induced by vaccination is well documented in the scientific literature for hybrid chicken of the layer and meat types. These data prove also innocuity and efficacy of the registered vaccines. In contrast, only a few and incomplete data exist on the development of ND directed immunity in fancy chickens. The present study describes vaccinations of chickens of 14 different hobby breeds with live LaSota vaccine (conjunctival application of 10(6) embryo-infective dose50 per bird) and with an inactivated oil-emulsion vaccine (intramuscular application of 0.5 ml per bird) and subsequent intramuscular challenge infections using the highly virulent NDV strain Herts 33/66. Chickens of all 14 breeds tolerated the application of both vaccines. All fancy chickens reacted with the production of serum antibodies which were measured in the haemagglutination inhibition (HI) and virus neutralisation (VN) tests. According to the scientific literature, maximal antibody levels are reached in hybrid chickens between day 10 and 20 post vaccination. In contrast, in fancy chickens the antibody maxima are delayed to the seventh to eighth week post vaccination. All fancy chickens vaccinated either once with live LaSota virus or with live and inactivated vaccines resisted challenge with the highly virulent Herts 33/66 strain of NDV and did not develop any signs of disease. There are indications for gradual differences in susceptibility of different breeds of fancy chickens. The levels of non-specific neutralisation as measured in the virus neutralisation test differ between breed. Also, the viral content in tissues obtained from non-vaccinated but challenged birds differ markedly. It is concluded from the results of this study that fancy chickens can also successfully protected against Newcastle disease by using live and inactivated vaccines which are licensed for hybrid chickens. However, the optimal time for the detection of maximal antibody levels in fancy chickens is reached seven to eight weeks post vaccination.  相似文献   

18.
Tetanus toxoid (TT) was assessed as a positive marker for avian influenza (AI) virus vaccination in chickens, in a vaccination and challenge study. Chickens were vaccinated twice with inactivated AI H5N2 virus vaccine, and then challenged three weeks later with highly pathogenic AI H5N1 virus. Vaccinated chickens were compared with other groups that were either sham-vaccinated or vaccinated with virus with the TT marker. All sham-vaccinated chickens died by 36 hours postinfection, whereas all vaccinated chickens, with or without the TT marker, were protected from morbidity and mortality following exposure to the challenge virus. Serological testing for H5-specific antibodies identified anamnestic responses to H5 in some of the vaccinated birds, indicating active virus infection.  相似文献   

19.
Development of a virosome vaccine for Newcastle disease virus   总被引：7，自引：0，他引：7  
In an effort to protect chickens against Newcastle disease (ND), a nonreplicating virosome vaccine was produced by solubilization of Newcastle disease virus (NDV) with Triton X-100 followed by detergent removal with SM2 Bio-Beads. Biochemical analysis indicated that the NDV virosomes had similar characteristics as the parent virus and contained both the fusion and hemagglutinin-neuraminidase proteins. To target the respiratory tract, specific-pathogen-free chickens were immunized intranasally and intratracheally with the NDV virosome vaccine. This vaccine was compared with a standard NDV (LaSota) live-virus vaccine for commercial poultry. Seroconversion (> or = four fold increase in hemagglutination inhibition [HI] antibody titers) was achieved in all birds vaccinated with the virosome vaccine. Upon lethal challenge with a velogenic NDV strain (Texas GB), all birds receiving either vaccination method were protected against death. Antibody levels against NDV, as determined by enzyme-linked immunosorbent assay and HI titer, were comparable with either vaccine and increased after virus challenge. These results demonstrate the potential of virosomes as an effective tool for ND vaccination.  相似文献   

20.
Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide (CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated. Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks.  相似文献   

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