共查询到20条相似文献，搜索用时 46 毫秒
1.
Efficacy and safety of a cell-culture live virus vaccine for hemorrhagic enteritis of turkeys: laboratory studies 总被引：1，自引：0，他引：1
Poults free from hemorrhagic enteritis (HE) antibody were vaccinated by gavage at 1 day or 2 weeks of age with a live HE vaccine virus that had been propagated in a Marek's disease (MD)-induced B-lymphoblastoid cell line of turkey origin. Vaccinated and unvaccinated poults were challenged with a virulent HE virus at various times postvaccination. One hundred tissue-culture-infectious doses of the vaccine virus per poult were sufficient to induce a serological response as well as to protect poults against HE lesions and mortality. Vaccinated poults were protected against the disease as early as 1 week and as late as 8 weeks PV. The vaccine was efficacious by several routes of application. The vaccine virus spread horizontally from vaccinated to contact-exposed poults, as indicated by seroconversion and resistance of contact-exposed poults to challenge. The vaccine had no detectable harmful effects on the humoral immune response to particulate antigens or on weight gain of vaccinated poults. The vaccine proved to be free from MD virus, as indicated by the absence of MD lesions and antibody in 8-week-old chickens inoculated intra-abdominally with the vaccine at hatching. These findings indicate that the cell-culture-propagated HE vaccine is efficacious and safe. 相似文献
2.
The clinical, pathological and microbiological outcome of a challenge with avian pneumovirus (APV) and Escherichia coli O2:K1 was evaluated in turkeys vaccinated with an attenuated APV vaccine and with or without maternally derived antibodies. Two groups of two-week-old poults, one with and one without maternally derived antibodies against APV, were vaccinated oculonasally with attenuated APV subtype A or B. A third group remained unvaccinated. Eleven weeks later, the turkeys were inoculated intranasally with either virulent APV subtype A, or E. coli O2:K1, or with both agents three days apart. After the dual infection, birds vaccinated with attenuated subtype A or B, and with or without maternally derived antibodies, had lower mean clinical scores than the unvaccinated birds. In the vaccinated birds, virus replication was significantly reduced and no bacteria were isolated, except from the birds vaccinated with attenuated subtype B. In the unvaccinated turkeys, large numbers of E. coli O2:K1 were isolated from the turbinates of the dually infected birds between one-and-a-half and seven days after they were inoculated. 相似文献
3.
A Mycoplasma gallisepticum (MG) isolate from an atypically mild outbreak in turkey breeders was found to be similar to house finch isolates by DNA analyses. A preliminary study in turkeys showed that this isolate (K5054) caused very mild lesions and protected turkeys against subsequent challenge with a virulent MG strain. In this study, K5054 was further evaluated as a potential vaccine strain in commercial layer-type chickens and turkeys. The safety of K5054 was evaluated by aerosol challenge followed by evaluation of gross and histopathologic lesions as well as serologic reactions and isolation of MG from the trachea and air sacs. Infection of chickens (trial 1) and turkeys (trial 2) with K5054 resulted in little evidence of MG lesions. There was weak seroconversion, and K5054 was consistently reisolated from the tracheas of chickens and turkeys. The efficacy of K5054 as a vaccine was evaluated by aerosol challenge of vaccinated chickens (trial 3) and turkeys (trial 4) with virulent R strain. There was evidence of protection from lesions associated with MG. 相似文献
4.
Kapczynski DR 《Avian diseases》2004,48(2):332-343
An avian metapneumovirus (aMPV) virosome vaccine was prepared and tested for protection of turkeys by aMPV challenge. The vaccine was produced using a detergent-based (Triton X-100) extraction of aMPV subtype C followed by detergent removal with SM2 Bio-Beads. Western blot and virus-neutralization analysis confirmed that the aMPV virosomes contained both the fusion and attachment glycoproteins. Specific-pathogen-free turkeys were immunized either intranasally (i.n.) or intramuscularly (i.m.) with two doses of the aMPV virosome vaccine. Vaccination decreased clinical signs of disease following virulent challenge, and IN vaccination was superior to i.m. vaccination in reducing clinical signs. Decreases in viral load in the respiratory tract were observed in turkeys receiving i.n. vaccination with aMPV virosomes compared to unvaccinated poults. Increased virus-neutralizing antibody levels against aMPV were observed in birds vaccinated with virosomes. These results demonstrate that immunization of turkeys with aMPV virosomes can be an effective strategy for control of disease. 相似文献
5.
Effect of cyclophosphamide immunosuppression on the immunity of turkeys to viral rhinotracheitis. 总被引：2，自引：0，他引：2
R C Jones C J Naylor A al-Afaleq K J Worthington R Jones 《Research in veterinary science》1992,53(1):38-41
Turkey poults, free of antibodies to turkey rhinotracheitis (TRT) virus were treated with cyclophosphamide on days 1, 2 and 3 after hatching and vaccinated by eyedrop when 10 days old with a Vero cell-attenuated preparation of TRT virus. No ELISA antibodies to TRT virus developed in the sera of these poults but they were as resistant to virulent virus challenge 21 days later as vaccinated groups which were not cyclophosphamide-treated but produced humoral antibodies. Following challenge with virulent virus at 31 days old cyclophosphamide-treated unvaccinated poults developed a more severe clinical response than untreated birds and had higher virus titres in tracheal swabs. The findings show that the respiratory tract of turkeys may be resistant to TRT despite the absence of ELISA antibodies in the serum. 相似文献
6.
7.
Four laboratory experiments were designed to study the efficacy of the only available commercial vaccine for turkey coryza, Art-Vax. Poults were vaccinated either once or twice at different ages and challenged with pathogenic Alcaligenes faecalis. In another study, commercial turkeys vaccinated at 1 and 12 days of age on a commercial farm were brought to the laboratory for challenge with pathogenic A. faecalis. Both the laboratory- and field-vaccinated poults were given the manufacturer's recommended dosage of the vaccine strain. Regardless of the vaccine schedule or source of poults, the vaccine was not effective in protecting challenged turkeys from infection. Furthermore, the vaccine was not effective in protecting poults less than 3 weeks of age from disease, but it was effective in protecting poults more than 3 weeks of age from disease. These results indicate that although vaccinated turkeys older than 3 weeks of age were not susceptible to disease, they were susceptible to infection and could act as carriers of field strains of A. faecalis, thus perpetuating the risk of infection to flocks subsequently raised in the same buildings. 相似文献
8.
Turkey poults were vaccinated with combinations of two different germling preparations and three adjuvants (N-acetylmuranyl-L-alanyl-D-isoglutamine, Pasteurella multocida lipopolysaccharide [LPS], and avridine) at 1 and 2 weeks of age, and their immunity was challenged by sublethal exposure to aerosols of Aspergillus fumigatus conidia at 1 month of age. Fewer turkeys in the groups given vaccines prepared from germlings grown on Dorset's and Henley's medium (D&H) had organisms in lung tissue at 2 weeks after challenge exposure as compared with those vaccinated with germling grown on neopeptone dialysate (Neo). The LPS of P. multocida appeared to be the most efficacious of the adjuvants in the D&H vaccine group, as A. fumigatus was isolated from only one of eight turkeys in this group; the number of organisms per gram of lung tissue was low compared with other vaccine groups at 2 weeks after challenge exposure; and poults given D&H vaccine with LPS as adjuvant had less-severe lung lesions than other groups. These differences in lung lesions were more marked at 2 weeks than at 8 weeks after challenge exposure. The only difference among other parameters in the vaccinated turkeys was lower heterophil counts in the turkeys given D&H-prepared vaccines than in unvaccinated controls. This was probably due to less-severe infections resulting from protective effects of these vaccines. 相似文献
9.
The food pellet vaccine has been shown to be effective in trials conducted under laboratory and simulated field conditions. The village chickens vaccinated with the food pellet vaccine during the field trial were protected against virulent Newcastle disease virus. The efficacy of the food pellet vaccine in the field was evaluated by challenge trial in which 60 per cent protection was obtained, or by monitoring the incidence of Newcastle disease in vaccinated and unvaccinated birds. There was no report of Newcastle disease outbreaks in the vaccinated birds during the two-year period of the field trial. The ease in administering the food pellet vaccine makes it readily accepted by the farmers. 相似文献
10.
Hemorrhagic enteritis of turkeys: influence of maternal antibody and age at exposure 总被引：1，自引：0，他引：1
The effect of maternal antibody (MAB) to hemorrhagic enteritis (HE) on the response of turkeys to infection with virulent and avirulent strains of HE virus (HEV) was examined. The influence of age at exposure and treatment with HEV antibody on development of clinical HE also was studied. MAB protected poults from clinical HE for up to 6 weeks of age. MAB also interfered with vaccination against the disease for at least 5 weeks after hatching, as indicated by absence of HEV antigen in spleens and by poor seroconversion at 6 days and at 3 weeks post-vaccination, respectively. The incidence of clinical HE in MAB-negative poults was significantly higher in poults inoculated with virus at 15 days of age or older than in poults inoculated at 1-13 days of age. Further, MAB-negative poults embryonally inoculated with virulent or avirulent strains of HEV did not develop disease; these poults developed antibody and resisted challenge with virulent virus at 6 weeks of age. Poults treated with HE antibody within 1 hour of challenge or at 1, 3, or 5 weeks before challenge with virulent virus were protected against lesions and mortality induced by HEV. These results suggest that MAB may influence susceptibility of turkeys to infection with HEV for at least 5 to 6 weeks after hatching, unlike the case with most other viral infections of poultry. The results confirm that early age resistance to clinical HE is independent of MAB and suggest that such resistance persists for up to 13 days of age. The data also suggest that turkeys lacking MAB can be immunized against HE by embryo vaccination. 相似文献
11.
A live cholera vaccine was developed from a virulent avian septicemia strain of Pasteurella multocida serotype 1. The virulent parental strain was mutagenized with N-methyl-N'-nitro-N-nitroso guanidine. Mutants were selected that had either smaller colonies at 37 C or temperature sensitivity for growth at 41 C. Four small-colony mutants and 2 temperature-sensitive mutants were studied. All the mutants were avirulent for turkeys. Sixteen days after turkeys were vaccinated with each mutant, both the vaccinates and unvaccinated controls were challenge-exposed to virulent P. multocida of the homologous serotype and the heterologous serotype 3. Two of the small-colony mutant strains protected against both homologous and heterologous challenge. Suggested for a live cholera vaccine is P. multocida M3G, a small-colony-forming mutant, innocuous for both mice and turkeys and stable against reversion. 相似文献
12.
Protection of turkeys from hemorrhagic enteritis with a recombinant fowl poxvirus expressing the native hexon of hemorrhagic enteritis virus. 总被引：5，自引：0，他引：5
Hemorrhagic enteritis (HE) is an economically important disease of turkeys caused by a type II aviadenovirus, hemorrhagic enteritis virus (HEV). The vaccines currently available to the commercial poultry producer are highly effective in preventing disease outbreaks; however, they are immunosuppressive. A recombinant fowl poxvirus (rFPV) expressing the native hexon of HEV has been shown to induce an anti-HEV humoral immune response in turkeys. In this study, the rFPV expressing the native hexon of HEV was compared with a commercial HEV vaccine (vxHEV) for its ability to protect turkeys from virulent HEV challenge. Complete protection from the enteritis of HE was achieved in experimental groups vaccinated with either the rFPV or the vxHEV. Lymphocyte stimulation was measured in turkeys inoculated with rFPV, vxHEV, or a sublethal dose of HEV or not inoculated. No statistically significant immunodepression was observed in turkeys receiving the rFPV. 相似文献
13.
Four-week-old poults obtained from avian pneumovirus (APV) antibody-free parents were vaccinated with different serial 10-fold dilutions of cell culture-propagated APV vaccine. The birds were vaccinated with 50 microl into each conjunctival space and nostril (total of 200 microl). Each poult of each group was vaccinated in groups that received doses of 4 x 10(4), 4 x 10(3), 4 x 10(2), 4 x 10(1), or 4 x 10(0) 50% tissue culture infective dose (TCID50) of APV vaccine, respectively. Respiratory signs were seen between 3 and 12 days postvaccination (PV) in the poults that were vaccinated with 4 x 10(4), 4 x 10(3), and 4 x 10(2) TCID50, respectively. In these groups, APV was detected from swabs collected at 5 days PV and seroconversion was detected at 2 wk PV. The groups that were originally vaccinated with 4 x 10(1) and 4 x 10(0) TCID50 developed mild clinical signs after vaccination, but neither virus nor antibody was detected PV. At 2 wk PV (6 wk of age), birds from each group, along with five unvaccinated controls, were challenged with APV. Upon challenge, the 4 x 10(4) and 4 x 10(3) TCID50 groups were protected against development of clinical signs and were resistant to reinfection. The group previously vaccinated with 4 x 10(2) TCID50 developed clinical signs after challenge that were considerably milder than those seen in the groups that had previously been vaccinated with lower doses or no virus. Even though 4 x 10(2) TCID50 vaccine dose administered by intranasal ocular route resulted in infection, incomplete protection resulted with this pivotal dose. Upon challenge, the 4 x 10(1) and 4 x 10(0) TCID50 groups exhibited milder disease signs than those seen in the challenged unvaccinated controls. In these groups, APV was detected in preparations of swabs collected at 5 days postchallenge (PC) and seroconversion was detected at 2 wk PC. These results indicate that the dose of APV vaccine that causes protection is higher than that required to produce infection. 相似文献
14.
Broad-breasted white turkeys were vaccinated with a temperature-sensitive mutant of Bordetella avium (Art Vax) at 2 and 15 days of age and challenged at 22 days of age by contact with infected birds. Necropsy was performed at 35 days of age. Two vaccination protocols (eyedrop/oral and spray cabinet/spray bottle) and two challenge isolates (Arkansas 105 and North Carolina [NC] isolates) were used. Neither the spray nor the eyedrop/oral methods of vaccination prevented infection of the anterior trachea with either of the virulent challenge strains. The spray and eyedrop/oral methods of vaccination were equally effective in reducing the severity of gross lesions in the trachea. The vaccine reduced the severity of gross lesions in the tracheas of turkeys challenged with the NC isolate to a level approximately equal to that observed in unchallenged vaccinated controls, but the vaccine only moderately reduced the severity of lesions in birds challenged with the 105 isolate. 相似文献
15.
In order to evaluate the protection conferred by an experimental inactivated vaccine against infectious coryza, three challenge trials were undertaken using 112 1-day-old broilers. The vaccine "Hepa Inmuno NC" included bacterial antigens of Avibacterium paragallinarum (serogroups A, B, variant B, and C) as well as antigens of Newcastle virus and hepatitis virus. Fifty-six broiler chicks were vaccinated at the first day of life at the hatchery while another 56 chicks were left unvaccinated. Three infection trials were conducted simultaneously using each of the three serogroups A, B, or C of Av. paragallinarum. In each trial, 17 vaccinated and 17 unvaccinated broilers were used. Challenge was performed at day 31 of life by injection, into the left infraorbital sinus, of approximately 1 x 10(5) colony forming units of the corresponding Av. paragallinarum strain. Clinical signs were recorded on day 2 postchallenge. All broilers were euthanatized and both infraorbital sinuses were bacteriologically examined for the presence of Av. paragallinarum on day 5 postchallenge. In comparison with the unvaccinated broilers, the vaccine significantly reduced the number of broilers with clinical signs after challenge with serogroup B, and significantly fewer vaccinated broilers were positive for the presence of Av. paragallinarum after challenge with serogroup C. On the other hand, no significant protection was observed when broilers were challenged with Av. paragallinarum from serogroup A. Despite the high infection rates in vaccinated chicks after an experimental infection with Av. paragallinarum, it was possible to reduce colonization of Av. paragallinarum (serogroup B) and clinical signs (serogroup C) in broiler chicks by vaccination at the first day of life. Further cross-protection trials should be done, including other Av. paragallinarum strains in the vaccine, especially those from serogroup A. 相似文献
16.
Protection of turkey poults from Bordetella avium infection and disease by pili and bacterins 总被引：1，自引：0，他引：1
The role of pili in protection against Bordetella avium infection in turkey poults was studied. An isolate that produced the largest number of pili under growth conditions developed in our laboratory was used for preparation of pili and bacterin and for challenge. The pili were isolated, purified, examined by electron microscopy, and tested for purity by gel electrophoresis. Poults were vaccinated with oil-adjuvant pili, formaldehyde- or merthiolate-inactivated bacterins, or a commercial bacterin. Poults were vaccinated once or twice subcutaneously at different ages and challenged intranasally with a pathogenic B. avium isolate 5 days following the last vaccination. A few vaccinated birds had very mild clinical signs. B. avium was isolated from the sinuses of a few vaccinated birds, and growth was scanty. The mean colony counts from tracheal sections was significantly higher (P less than 0.1) in unvaccinated challenged poults than in vaccinated challenged poults. It is postulated that B. avium pili are important immunogens in turkey poults. 相似文献
17.
The efficacy of a commercially produced temperature-sensitive mutant Alcaligenes faecalis vaccine was evaluated in turkeys contact-challenged with one of three strains of A. faecalis. In the vaccinated control group, the vaccine strain of A. faecalis colonized the nasal turbinates but not the trachea, caused no clinical signs of turkey coryza, and induced humoral antibodies. In the vaccinated challenged groups, the vaccine reduced both the severity of lesions and the number of birds exhibiting lesions compared with unvaccinated challenged groups, but it did not prevent colonization of challenge strains of A. faecalis. 相似文献
18.
The M-9 and Minnesota (MN) avirulent Pasteurella multocida vaccines were evaluated and compared with the Clemson University (CU) vaccine, which had been shown to be highly effective in preventing fowl cholera in turkeys. Neither the M-9 nor the MN vaccine given in the drinking water was as effective as the CU vaccine in protecting turkeys against challenge with virulent P. multocida. When grown in brain-heart infusion (BHI) agar as recommended, the M-9 was not as efficacious as when it was grown in BHI broth. The M-9 was as effective as the CU vaccine only when grown in BHI broth and given at 10 times the standard dosage. Injection of the M-9 vaccine into the air spaces of the head at a site near the caudal rim of the ear after one vaccination in the drinking water was not as effective for hyperimmunizing potential breeders as was the CU vaccine injected at the same site. A microtiter agglutination test demonstrated a significant (P less than 0.05) correlation between the level of anti-P. multocida antibody found 1 week after vaccination and survival after challenge with virulent P. multocida. 相似文献
19.
Studies were performed to determine if mucosal vaccination with inactivated avian metapneumovirus (aMPV) subtype C protected turkey poults from clinical disease and virus replication following mucosal challenge. Decreases in clinical disease were not observed in vaccinated groups, and the vaccine failed to inhibit virus replication in the tracheas of 96% of vaccinated birds. Histopathologically, enhancement of pulmonary lesions following virus challenge was associated with birds receiving the inactivated aMPV vaccine compared to unvaccinated birds. As determined by an enzyme-linked immunosorbent assay (ELISA), all virus-challenged groups increased serum immunoglobulin (Ig) G and IgA antibody production against the virus following challenge; however, the unvaccinated aMPV-challenged group displayed the highest increases in virus-neutralizing antibody. On the basis of these results it is concluded that intranasal vaccination with inactivated aMPV does not induce protective immunity, reduce virus shedding, or result in decreased histopathologic lesions. 相似文献
20.
《The Journal of Applied Poultry Research》2014,23(3):478-485
The objective of this work was to develop and evaluate the immunomodular effect of a DNA vaccine based on the fusion (F) gene of avian metapneumoviruses (aMPV) and to study its protection against field virus challenge, as this will help to better control the disease in turkeys. In this study, the F protein of the Egyptian isolate (Giza-turkey rhinotracheitis-4) of the B-subtype of aMPV isolated in 2009 was expressed from a DNA plasmid in Vero cells. After 1 i.m. injection of turkey poults with this plasmid, the antibody response was detected by ELISA. The turkey poults inoculated with locally prepared DNA aMPV vaccine had highly significant phagocytic activity, as measured by phagocytic percent and index of macrophage activation, in comparison to those inoculated with inactivated and live attenuated vaccines and with the noninfected control group. Intratracheal challenge of turkey poults at 21 d postvaccination by a dose of 100 uL of field Egyptian Giza-turkey rhinotracheitis-4 virus of a titer 6 log10 tissue culture infective dose 50 resulted in 100% protection in poults that received locally prepared DNA aMPV vaccine, whereas those that received commercial aMPV vaccines experienced 80 and 90% protection; typical clinical signs of aMPV infection were seen in control nonvaccinated poults. Therefore, a high success rate was noted when using F gene DNA plasmid vaccine by the induction of a potent immunomodular effect for both cell-mediated and humoral immune response. The use of the F gene DNA plasmid vaccine developed in this study provided 100% protection in vaccinated poults, which can help in controlling aMPV infections in turkeys. 相似文献