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1.
J M Sharma 《Avian diseases》1985,29(4):1155-1169
Studies with specific-pathogen-free chickens revealed that chicks hatching from eggs inoculated at the 18th day of embryonation with infectious bursal disease (IBD) vaccine viruses of low virulence (isolates TC-IBDV and BVM-IBDV) developed antibody against IBD virus (IBDV) and resisted challenge with virulent IBDV at 3 weeks of age or older. Embryo vaccination did not adversely affect hatchability of chicks or survival of hatched chicks. Chicks embryonally vaccinated with TC-IBDV had transient histologic lesions in the bursa of Fabricius at hatch. Similar but milder lesions were also noted in chickens that received TC-IBDV at hatch. The level of protection following embryo vaccination with TC-IBDV and BVM-IBDV was similar to that following vaccination with the same vaccines at hatch. Vaccine viruses of moderate virulence (isolates BV-IBDV and 2512-IBDV) were not suitable as vaccines in embryos lacking maternal antibody to IBDV, because the vaccinated chicks developed acute IBD after hatch. Isolate 2512-IBDV was not pathogenic for embryos bearing maternal antibody to IBDV. Maternal antibody against IBDV interfered with efficacy of embryo vaccination with BVM-IBDV but not with 2512-IBDV. Embryo vaccination with a mixture of vaccines against IBD and Marek's disease resulted in protection of hatched chicks against challenge with virulent IBDV and Marek's disease virus.  相似文献   

2.
Control of infectious bursal disease virus (IBDV) by vaccination is important for poultry production worldwide. Two vaccines, an IBDV immune complex (ICX) vaccine and an IBDV-2512 vaccine, were administered at 100 mean embryo infectious dose to specific-pathogen-free 18-day-old broiler embryos in ovo. At 3, 6, 9, 15, and 21 days post in ovo vaccination (PIOV), bursa, spleen, and thymus tissues were collected and analyzed for virus protein by antigen capture chemiluminescent enzyme-linked immunosorbent assay (ELISA). Chicks were bled and antibody titers were determined by the antibody ELISA. At 21 days PIOV, chickens were challenged with a 1:500 dilution of an antigenic standard IBDV strain. At 28 days PIOV, birds were euthanatized and bursa weight:body weight ratios were determined. Embryos vaccinated with either vaccine exhibited 92% hatchability; however, within 1 wk of hatch, birds vaccinated with IBDV-2512 showed 56% mortality, whereas those given IBDV-ICX had only 3.2% mortality. Both IBDV-ICX and IBDV-2512 vaccines were detected in bursa, spleen, and thymus at day 3 PIOV. A 5-day delay in virus replication was observed with IBDV-ICX vaccine. By day 15 PIOV, the IBDV-ICX was no longer detectable in the bursa and spleen but persisted in the thymus. The IBDV-2512 vaccine persisted in the spleen and thymus on day 15 PIOV. By day 21 PIOV, neither vaccine virus was detected in any lymphoid organ. This assay can be useful in the early detection of vaccine virus in the tissues of chickens vaccinated via the in ovo route. Both vaccines caused bursal atrophy at all times PIOV. The IBDV-2512 caused splenomegaly at day 6 PIOV, whereas splenomegaly was not seen in IBDV-ICX-vaccinated birds until day 9 PIOV. Thymus atrophy was observed in IBDV-2512-vaccinated chicks from day 3 PIOV, whereas this occurred on day 15 PIOV in IBDV-ICX-vaccinated birds. Bursa weight: body weight ratios in IBDV-ICX-vaccinated unchallenged and vaccinated challenged birds were not different (P < 0.05).  相似文献   

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Infectious bursal disease (IBD) causes severe economic damage to the poultry industry worldwide. To prevent IBD virus (IBDV) infection, live virus vaccines have been widely used in chickens having wide-ranging levels of maternally derived antibodies. But, the risks of infection with other pathogens because of lesions related to atrophy of the bursa of Fabricius in vaccinated chickens are a concern. To resolve the problems, a recombinant turkey herpesvirus (HVT) vaccine expressing IBDV-VP2 protein (rHVT-IBD) has been developed. However, the induction of neutralizing antibodies by rHVT-IBD against a virulent IBDV might be delayed compared with that by the live IBD vaccine, leading to the high risks of IBDV infection for young chickens. To find the best selection of IBDV vaccine for the onset of immunity, we examine the protective efficacy of a novel in ovo-attenuated live IBDV (IBD-CA) vaccine and the rHVT-IBD vaccine in young chickens challenged with a very virulent IBDV (vvIBDV) strain. We show that the protective efficacy of IBD-CA vaccine was higher than that of the rHVT-IBD vaccine in 14-day-old chickens challenged with the vvIBDV strain, leading to the risk of IBDV infection for young chickens when vaccinated with rHVT-IBD. Our results suggest that farmers should select the best vaccines to maximize vaccine efficacy in consideration of the vaccine characteristics, prevalence levels of IBDV in the areas, and initial MDA levels of the chickens since the attenuated live and recombinant vaccines play a role in the different vaccine efficacies.  相似文献   

6.
Infectious bursal disease virus variant from commercial Leghorn pullets   总被引:5,自引:0,他引:5  
An infectious bursal disease virus (IBDV) was isolated from 39-to-43-day-old commercial leghorn pullets suspected of having infectious bursal disease (IBD). These chickens had been vaccinated with a commercial live IBDV vaccine at 28 and 35 days of age. An isolate designated IN was recovered using specific-pathogen-free (SPF) chickens and the BGM-70 established cell line. Experimental studies using SPF chickens vaccinated with either inactivated vaccines made from the vaccine strain used in the problem flock or a standard-type vaccine indicated no protection against the IN isolate. However, two variants and another standard-type vaccine induced protection against the IN isolate. Cross-neutralization tests indicated that the IN isolate differed antigenically from commercial vaccine strains and was related to the variant IBDV strains recently isolated from broilers. To our knowledge, this is the first report of a variant IBDV recovered from commercial layer chickens in the United States.  相似文献   

7.
Chickens were vaccinated with the herpesvirus of turkeys (HVT) at embryonation day 17 or 18 or at hatch and various responses of the 2 vaccinated groups were compared. In embryo-vaccinated chickens, HVT titers were high in the lungs before HVT could be isolated from other tissues. Seemingly, embryos acquired infection via the respiratory tract. In hatch-vaccinated chickens, HVT was first isolated from spleen and then from other tissues. Titers of recoverable HVT in tissues of embryo-vaccinated chickens were higher than in those of hatch-vaccinated chickens, particularly during the 1st week of age. Anti-HVT antibodies and natural killer cell reactivity in spleen effector cells were comparably increased in both vaccinated groups. Embryo vaccination with HVT did not cause progressive lesions, reduction in body weight gain, or impairment of humoral and cellular immune functions. Seemingly, HVT can be used safely as an embryonal vaccine in chickens.  相似文献   

8.
Marek's disease virus (MDV) vaccines of serotypes 1 and 2 administered in 18-day-old embryonated eggs induced better protection against post-hatch challenge at 3 days with virulent MDV than vaccines given at hatch. Embryonal vaccination with a polyvalent vaccine containing equal quantities of serotypes 1 and 2 of MDV and serotype 3 virus (turkey herpesvirus, HVT) was also significantly more effective than post-hatch vaccination. These and earlier results indicate that protective efficacy of single or combined Marek's disease vaccine serotypes against post-hatch challenge at 3 days can be substantially improved if the vaccines are injected into 18-day embryos rather than at hatch. Injection of vaccines of serotypes 1 or 2 into embryonated eggs or hatched chicks did not cause detectable gross or microscopic lesions in chickens. Vaccine viruses of serotypes 1 and 2 could be isolated from spleen cells of chickens 1 week post-vaccination, and the titer of recoverable viruses was higher in chickens that received the vaccines at the 18th day of embryonation than in chickens vaccinated at hatch. Although embryo vaccination with HVT usually provided better protection than post-hatch vaccination against early post-hatch challenge with variant pathotypes of MDV, the protection was poor regardless of vaccination protocol. If challenge with variant pathotypes of MDV was delayed until embryonally or post-hatch HVT-vaccinated chickens were 21 days of age, protection of chickens by HVT was not enhanced. Thus, resistance induced by embryonal vaccination with HVT was qualitatively similar to that induced by post-hatch vaccination with this virus.  相似文献   

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Abdel-Alim GA  Saif YM 《Avian diseases》2002,46(4):1001-1006
The pathogenicity of serotype 2 OH strain of infectious bursal disease virus (IBDV) to specific-pathogen-free (SPF) chicken embryos and 2-wk-old SPF chickens and turkey poults was investigated. The virus was pathogenic for chicken embryos after five passages as evidenced by pathologic changes in inoculated embryos. The embryo-adapted virus was not pathogenic for 2-wk-old SPF chickens and turkey poults as indicated by lack of clinical signs, gross or microscopic lesions in the bursa of Fabricius of inoculated birds. Bursa-to-body-weight ratios of the inoculated chickens and turkey poults were not significantly different from those of uninoculated controls. Virus-neutralizing antibodies to serotype 2 IBDV were detected in inoculated chickens and turkeys. Results of this study indicated that the embryo-adapted serotype 2 OH IBDV isolate that is pathogenic for chicken embryos is infectious but not pathogenic in chickens and turkeys.  相似文献   

12.
Specific-pathogen-free chickens orally inoculated at 4 days of age with a moderately pathogenic vaccine strain of infectious bursal disease virus (IBDV) and/or at 5 days of age with Cryptosporidium baileyi oocysts remained free of overt clinical signs throughout a 16-day period postinoculation (PI). The prepatency period for C. baileyi oocyst shedding was shorter in chickens receiving higher numbers of oocysts, but once shedding was detected, there were no obvious differences in shedding patterns among groups receiving 10(3) through 10(6) oocysts. On days 8 and 16 PI, cryptosporidia were located primarily in the bursae of Fabricius. IBDV exposure was associated with bursal follicle atrophy, whereas C. baileyi infection resulted in bursal epithelial hypertrophy and hyperplasia, mild follicle atrophy, and heterophil infiltration of the bursal mucosa. Examination of experimental groups of 30 birds each indicated that concurrent infection with both agents resulted in more severe bursal lesions, more infected birds, and greater numbers of cryptosporidia in infected tissues. At the termination of the trial, 16 days PI, Cryptosporidium infection was associated with a 6% decrease in mean body weight compared with controls.  相似文献   

13.
国内外很多学者都在进行着传染性法氏囊(Infectious bursal disease,IBD)各种基因工程疫苗的研制,IBDV-vp2基因在多种载体中得到表达并取得了较好的保护效力。本实验室已构建了表达IBDV-vp2基因的重组马立克氏病病毒。本研究对该重组马立克氏病病毒疫苗的遗传稳定性以及对SPF鸡和含有母源抗体的商品鸡的免疫保护作用进行了评价。结果表明,103 PFU和104 PFU剂量的重组病毒免疫后对SPF鸡抗传染性法氏囊标准强毒的保护率分别为53%和73%。104 PFU剂量的重组病毒免疫后对含有母源抗体的商品鸡抗传染性法氏囊标准强毒的保护率为87%,结果显示重组疫苗具有一定的应用前景。  相似文献   

14.
Infectious bursal disease (IBD) is characterized by immunosuppression due to the depletion of lymphocytes in the atrophied bursa of Fabricius (BF). We have sometimes encountered contradictory findings: chickens infected with the vaccine IBD virus (IBDV) strain have sometimes exhibited a highly atrophied BF, but not immunosuppression. In this study, chickens administered vaccine or wild-type strains of IBDV were later vaccinated with the B1 strain of the Newcastle disease virus (NDV). Bursal changes were examined histologically with a focus on the bursal follicle. The immunoreactivity to NDV was also evaluated with the hemagglutination inhibition test. In gross examination, we observed a few chickens with a severely atrophied BF in vaccine strain-administered groups (vaccine groups), and the level of severity was the same as that in the wild-type strain-administered group (wild-type group). However, these chickens retained humoral antibody responses to NDV and were revealed to possess a higher number of bursal follicles than those of the wild-type group. These results indicated that macroscopic evaluation dose not accurately reflect the immunoreactivity and degree of bursal damage in IBDV-administered chickens. We also found non-immunosuppressed chickens in the wild-type group. These non-immunosuppressed chickens retained a significantly higher number of normal follicles and total follicles according to our statistical analysis. Furthermore, a high correlation coefficient between the NDV-HI titer and the number of normal follicles was found in the wild-type group. These results implied that the retained number of normal follicles is important for the immunoreactivity of chickens infected with IBDV.  相似文献   

15.
Different infectious bursal disease virus (IBDV) live vaccines (intermediate, intermediate plus) were compared for their immunosuppressive abilities in specific-pathogen-free (SPF) layer-type chickens or commercial broilers. The Newcastle disease virus (NDV) vaccination model was applied to determine not only IBDV-induced immunosuppression but also bilateral effects between IBDV and NDV. None of the IBDV vaccines abrogated NDV vaccine-induced protection. All NDV-vaccinated SPF layers and broilers were protected against NDV challenge independent of circulating NDV antibody levels. Sustained suppression of NDV antibody development was observed in SPF layers, which had received the intermediate plus IBDV vaccine. We observed a temporary suppression of NDV antibody development in broilers vaccinated with one of the intermediate, as well as the intermediate plus, IBDV vaccines. Different genetic backgrounds, ages, and residual maternal antibodies might have influenced the pathogenesis of IBDV in the different types of chickens. Temporary suppression of NDV antibody response in broilers was only seen if the NDV vaccine was administered before and not, as it was speculated previously, at the time the peak of IBDV-induced bursa lesions was detected. For the first time, we have demonstrated that the NDV vaccine had an interfering effect with the pathogenesis of the intermediate as well as the intermediate plus IBDV vaccine. NDV vaccination enhanced the incidence of IBDV bursa lesions and IBDV antibody development. This observation indicates that this bilateral effect of an IBDV and NDV vaccination should be considered in the field and could have consequences for the performance of broiler flocks.  相似文献   

16.
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   

17.
A multivalent in ovo vaccine (MIV) was tested for safety and efficacy in a commercial broiler complex. The MIV comprised five replicating live viruses including serotypes 1, 2, and 3 of Marek's disease virus (MDV), an intermediate infectious bursal disease virus (IBDV) and a recombinant fowl poxvirus (FPV) vector vaccine containing HN and F genes of Newcastle disease virus (NDV). The performance of MIV-vaccinated broilers was compared with that of hatchmates that received turkey herpesvirus (HVT) alone (routinely used in ovo vaccine in the broiler complex). The chickens that hatched from the MIV-injected and HVT-injected eggs were raised under commercial conditions in six barns. Barn 1 housed 17,853 MIV-vaccinated chickens and each of the barns 2-6 housed 18,472-22,798 HVT-vaccinated chickens. The HVT-vaccinated chickens were given infectious bronchitis virus (IBV) and NDV vaccines at hatch and at 2 wk of age. The MIV-vaccinated chickens received IBV vaccine at hatch and IBV + NDV at 2 wk of age. The relative values of hatchability of eggs, livability and weight gain of chickens, and condemnation rates at processing were comparable between the MIV and the HVT groups (P > 0.05). Chickens from the MIV- and the HVT-vaccinated groups were challenged with virulent viruses under laboratory conditions. The resistance of vaccinated chickens against Marek's disease could not be assessed because of high natural resistance of unvaccinated commercial broilers to virulent MDV. The relative resistances of the MIV- and the HVT-vaccinated groups, respectively, against other virulent viruses were as follows: IBDV, 100% for both groups; NDV, 81% vs. 19%; FPV, 86% vs. 0%. The successful use of MIV under field conditions expands the usefulness of the in ovo technology for poultry.  相似文献   

18.
The prevalence of infectious bursal disease virus (IBDV) was studied in chickens, which had not been vaccinated against IBD. Fifty sera and forty-six bursae of Fabricius from chickens showing impaired growth, collected from 7 IBD vaccination-free farms in Japan were used for virus neutralization (VN) tests and RT-PCR for detection of IBDV genome corresponding to the VP2 hypervariable region. Of the fifty sera, 39 sera (78%) from 6 farms were VN antibodies positive. Of the forty-six bursae, 37 bursae (80.4%) from 6 farms were positive in the RT-PCR assay. The sequences of all the RT-PCR products detected in this study were closely related or identical to those of the vaccine strains. These results show that vaccine-like IBDV is prevalent even in IBD vaccine-free chicken farms in Japan.  相似文献   

19.
The appearance of very virulent strains of infectious bursal disease (IBD) virus at the end of the 1980s made it necessary to develop more effective immunization procedures. To facilitate this, the immunogenicity and the immunosuppressive effect of a mild (G-87), an intermediate (LIBD) and an intermediate-plus (IBDV 2512) IBDV strain were tested after the in ovo inoculation of 18-day-old SPF and broiler chicken embryos. It was established that no noteworthy difference existed between the immunized and the control embryos in hatching rate and hatching weight. The higher the virulence of the vaccine virus strain, the more severe damage it caused to the lymphocytes of the bursa of Fabricius. In SPF chickens, the haemagglutination inhibition (HI) titres induced by a Newcastle disease (ND) vaccine administered at day old decreased in inverse ratio to the virulence of the IBD vaccine strain, while in broiler chickens this was not observed. Despite the decrease of the HI titre, the level of protection did not decline, or did so only after the use of the 'hot' strain. SPF chickens immunized in ovo with a complex vaccine prepared from strain IBDV 2512 and IBD antibody showed the same protection against Newcastle disease as the broilers. In broiler chicken embryos immunized in ovo, only strain IBDV 2512 induced antibody production, and such chickens were protected against IBD at 3 weeks of age. The complex vaccine administered in ovo has been used successfully at farm hatcheries as well.  相似文献   

20.
We investigated embryo tissues targeted by replication competent adenovirus (Ad)-free recombinant Ad expressing a codon-optimized avian influenza (AI) H5 gene from A/turkey/WI/68 (AdH5) when injected into 18-day embryonated eggs. We also evaluated the effects of concurrent in ovo vaccination with the experimental AdH5 vaccine and commercially available Marek's disease virus (MDV) vaccine combinations Rispens/turkey herpesvirus (HVT) or HVT/SB-1. Computed tomography indicates that in ovo injection on day 18 of incubation places the solution in the amnion cavity, allantoic cavity, or both. Ad DNA was consistently detected in the chorioallantoic membranes as well as in the embryonic bursa of Fabricius, esophagus, and thymus 3 days postinoculation. H5 expression in these tissues also was detected by immunofluorescence assay. These results indicate possible swallowing of vaccine virus contained in the amnion. In contrast, vaccine localization in the allantoic fluid would have allowed bursal exposure through the cloaca. When the AdH5 vaccine was used in combination with MDV, chickens responding to the AdH5 vaccine had similar AI antibody levels compared with AdH5-only-vaccinated birds. However, combined vaccinated groups showed reduced vaccine coverage to AI, suggesting some level of interference. The combination of AdH5 with MDV Rispens/HVT affected the vaccine coverage to AI more severely. This result suggests that the replication rate of the more aggressive Rispens strain of serotype 1 may have interfered with the Ad-vectored vaccine. Increasing the Ad concentration produced similar AI antibody titers and AI vaccine coverage when applied alone or in combination with the HVT/SB-1 vaccine. Ad DNA was detected in hatched chickens 2 days after hatch but was undetectable on day 9 after hatch. MDV DNA was detected in feather follicles of all vaccinated birds at 12 days of age. Thus, Ad-vector vaccination does not interfere with the efficacy of MDV vaccination by using any of the commonly used vaccine strains.  相似文献   

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