共查询到20条相似文献，搜索用时 46 毫秒
1.
A temperature-sensitive (Ts) mutant strain of Ornithobacterium rhinotracheale (ORT) was developed after exposure of the wild-type organism to N-methyl-N'-nitro-N-nitrosoguanidine. The Ts mutant strain grew at 31 C but had its growth inhibited at 41 C unlike wild-type parent strain. The Ts mutant and parent strains were characterized. Morphologic and biochemical properties of wild-type and mutant strains did not show any differences. The strains were also characterized by polymerase chain reaction (PCR)-based fingerprinting methods. Results showed similar patterns in repetitive sequences by repetitive PCR (enterobacterial repetitive intergenic consensus, highly conserved repeated DNA elements present in Streptococcus pneumoniae (BOX), repetitive extragenic palindromic, and Salmonella enteritidis repetitive element primers); however, random amplified polymorphic DNA fingerprinting was able to differentiate mutant and parent strains showing a unique pattern for each of the ORT strains. The rationale for the use of a Ts strain as a vaccine is based on the ability of the mutant to colonize the upper respiratory tract but not the lower respiratory tract and systemic system of the birds, where the wild-type strain causes severe lesions. In a preliminary evaluation, Ts strain of ORT was recovered from tracheas and choanae of Ts-treated turkeys for 13 days postadministration of the strain either in drinking water or by oculonasal instillation. Humoral immune response was detected in Ts-vaccinated but not in control group birds after 3 wk postadministration. Results suggest that Ts strain of ORT has promising potential use as a live vaccine for ORT. 相似文献
2.
3.
Kilany WH Abdelwhab EM Arafa AS Selim A Safwat M Nawar AA Erfan AM Hassan MK Aly MM Hafez HM 《Veterinary microbiology》2011,150(1-2):28-34
In contrast to chickens, there is a paucity of information on the potency of H5 vaccines to protect turkeys against the highly pathogenic avian influenza (HPAI) H5N1 virus infections. In this study, 4 groups, 10 turkey poults each, were vaccinated at seven days old with one of H5N2 or H5N1 commercial vaccines or one of two prepared H5N1 vaccines from a local Egyptian variant HPAI H5N1 (EGYvar/H5N1) strain. At 35 days age, all vaccinated and 10 non vaccinated birds were challenged intranasal with 10(6) EID(50)/0.1 ml of EGYvar/H5N1. All vaccines used in this study were immunogenic in turkeys. There was no cross reaction between the commercial vaccines and the Egyptian variant H5N1 antigen as obtained by the hemagglutination inhibition test. Birds vaccinated with H5N2 vaccine were died, while other H5N1 vaccinated groups have had 20-40% mortality. The highest virus excretion was found in non-vaccinated infected and H5N2 vaccinated birds. Eleven peculiar amino acid substitutions in H5 protein of the variant strain were existed neither in the vaccine strains nor in the earliest H5N1 virus introduced into Egypt in 2006. In conclusion, single vaccination at seven days old is inadequate for protection of meat turkeys against variant HPAI H5N1 challenge and multi-dose vaccination at older age is recommended. For the foreseeable future, continuous evaluation of the current vaccines in H5N1 endemic countries in the face of virus evolution is a paramount challenge to mitigate the socio-economic impact of the virus. 相似文献
4.
Okuda Y Kuroda M Ono M Chikata S Shibata I 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(10):1017-1025
The objective of this study was to evaluate the influences of genetic and antigenic variations in field isolates of porcine reproductive and respiratory syndrome virus (PRRSV) on vaccine efficacy. Four-week-old pigs were vaccinated with a commercial modified live virus vaccine. Four weeks after vaccination, pigs in both the vaccinated group and the non-vaccinated group were challenged intranasally with 10(7) TCID(50) of PRRSV wt-11 (Experiment 1) or PRRSV wt-7 (Experiment 2). Based on genome sequencing of ORF5 and cross neutralization test results, PRRSV wt-11 is similar to the vaccine strain, whereas wt-7 is distinct from the vaccine strain. In the vaccinated challenged groups, clinical signs were less severe, the mean rate of weight gain was greater, and gross lung lesions were less severe when compared with the non-vaccinated challenged groups in both experiments. In Experiment 1, the virus was isolated from serum at 3 days post-challenge, and the mean virus titers in broncho-alveolar lavage fluids (BALF) and tissues were lower in pigs in the vaccinated challenged groups compared with those in the non-vaccinated challenged group. In Experiment 2, virus isolation from serum, BALF and tissues showed no significant differences between the groups. These results suggest that commercial PRRSV vaccine could be effective in reducing clinical disease following a challenge with field isolates of PRRSV. However, with regards to virological protection, the efficacy of the vaccine may be affected by the nature of the PRRSV isolates. 相似文献
5.
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
6.
The purpose of this work was to develop a live, attenuated vaccine strain to protect chickens against colonization by group C Salmonella. We constructed two candidate vaccines: a deltacya deltacrp derivative and a deltaphoP derivative of Salmonella hadar. White Leghorn chickens were vaccinated at day of age and at 2 wk with one of the two strains. A nonvaccinated group served as a control. At 4 wk of age, all birds were challenged with wild-type S. hadar and necropsied 6 days later. Numbers of S. hadar in the ceca were determined. Enzyme-linked immunosorbent assay-derived serum immunoglobulin G responses against S. hadar lipopolysaccharide indicated that both strains induced a serum antibody response. The average optical density450 for birds vaccinated with the deltaphoP or deltacya deltacrp derivatives was 0.456 and 0.881, respectively. Although the deltacya deltacrp derivative induced higher levels of serum antibody, it did not provide an immune response protective against colonization by S. hadar. Conversely, birds vaccinated with the deltaphoP strain showed significant protection against S. hadar challenge. Seventy percent of the nonvaccinates, 60% of the deltacya deltacrp vaccinates, and 15% of deltaphoP vaccinates were positive for S. hadar in tissues. In a second experiment, birds were vaccinated with either the deltaphoP strain or buffer and challenged with a 10-fold higher dose than in the first experiment. After challenge, all of the birds in both groups were colonized. The geometric mean number of cecal S. hadar isolated from the control group was 1.0 x 10(6) colony-forming units (CFU)/g, and from the vaccinated group, this value was 32 CFU/g, indicating a four to five log reduction in colonization by the challenge strain. 相似文献
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.
Influence of a reovirus-antibody complex vaccine on efficacy of Marek's disease vaccine administered in ovo 总被引：2，自引：0，他引：2
Two experiments determined the influence of an experimental reovirus-antibody complex vaccine on Mareks disease virus (MDV) vaccine when used in ovo. Designs were the same except that specific-pathogen-free (SPF) broiler eggs were used in Experiment 1 and commercial broiler eggs with maternal antibodies against reovirus were used in Experiment 2. At 18 days of incubation, embryos were separated into four groups and inoculated with either diluent, MDV vaccine, reovirus-antibody complex vaccine, or a combination of reovirus-antibody complex and MDV vaccine. At 5 days of age, half the chickens in each group were challenged with MDV. At 7 wk old, all were euthanatized, weighed, and examined. At 7 days of age, remaining chickens in each group were challenged with reovirus. At 21 days old, chickens were euthanatized and weighed. No vaccine adversely affected hatchability or posthatch mortality in SPF or commercial chickens. There were no significant differences in protection against reovirus challenge when vaccines were used separately or in combination, and lesion scores were nearly identical in all vaccinated groups in both experiments. However, percentage of protection against reovirus was lower in Experiment 2, indicating an adverse effect of maternal immunity on efficacy of the reovirus vaccine. There were no significant differences in protection against MDV when the vaccines were used separately or combined. Severity of MDV lesions was nearly identical in all vaccinated groups in both experiments. However, the combination of vaccines gave numerically lower protection against MDV than MDV vaccine alone. Use of a larger number of birds, as in field conditions, may result in statistically lower protection for the vaccine combination. Large field trials are needed to determine the potential of the reovirus-antibody complex vaccine. 相似文献
9.
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
10.
Duration of immunity engendered by a single dose of a cold-adapted strain of Avian pneumovirus 
下载免费PDF全文
下载免费PDF全文 The duration of immunity after a single dose of a cold-adapted strain of Avian pneumovirus (APV) was studied. Turkeys were vaccinated at 1 wk of age and challenged with virulent virus 3, 7, 10, and 14 wk later. Nonvaccinated groups were also challenged at the same times. No clinical signs were observed in the vaccinated birds after vaccination or after any challenge. No viral RNA was shed by the vaccinated birds after any challenge. The nonvaccinated birds shed viral RNA after all challenges. Avian pneumovirus-specific humoral antibodies were detected in the vaccinated birds until 14 wk after vaccination. The results of this preliminary study indicate that inoculation with a single dose of a cold-adapted strain of APV at 1 wk of age provides protection until 15 wk of age. 相似文献
11.
J R Andreasen J R Glisson M A Goodwin R S Resurreccion P Villegas J Brown 《Avian diseases》1989,33(3):516-523
Broiler chickens were vaccinated at 18 days of age against infectious laryngotracheitis (ILT) using chicken-embryo-origin (CEO) and tissue-culture-origin (TCO) vaccines, each vaccine given either by drinking water, spray, or eyedrop. Controls were not vaccinated. The broilers were challenged 3 weeks later with virulent ILT virus (USDA challenge strain). Serum samples taken before challenge were analyzed by a virus neutralization (VN) test to determine titers due to vaccination. Both vaccines, regardless of route of administration, produced low VN titers, geometric mean titer (GMT) being less than 4.0 in all vaccinated groups. When administered by the same route, the CEO vaccine produced higher titers than the TCO vaccine. Titers following drinking-water or eyedrop administration of vaccines were higher than titers following spray vaccination. There was an inverse relationship between pre-challenge VN titers of groups of birds and the percentage of birds in the groups dying from ILT virus challenge. The drinking-water route of vaccination provided the most protection, while the spray provided the least. 相似文献
12.
Ornithobacterium rhinotracheale has been shown to cause serious clinical illness and is a significant concern to the turkey industry because of its potential economic impact. In this study, 6-wk-old turkeys were vaccinated intranasally with a live or subcutaneously with a killed O. rhinotracheale vaccine. At 14 or 21 wk of age, the birds were challenged intratracheally with live O. rhinotracheale. Airsacculitis and pneumonia occurred less frequently in vaccinated birds than in unvaccinated birds after challenge with O. rhinotracheale. Ornithobacterium rhinotracheale was recovered from unvaccinated, challenged birds but not from vaccinated, challenged or from unchallenged birds. Thus, turkeys inoculated with live or killed O. rhinotracheale vaccine were protected from pathologic changes. 相似文献
13.
A live attenuated Mycoplasma gallisepticum vaccine, ts-11, has been used for control of M gallisepticum in several countries. The rapid serum agglutination test is usually used as an indicator of flock response to vaccination; however, in some flocks, the detected response may be weak or absent. We investigated whether the low level, or lack, of systemic antibodies in ts-11-vaccinated flocks is correlated with susceptibility to infection after challenge with a virulent M. gallisepticum strain. Birds from 2 separate ts-11-vaccinated commercial flocks with no, or weak, rapid serum agglutination responses (at 11 or 14 wk postvaccination) were randomly selected and subjected to aerosol challenge with either M gallisepticum strain Ap3AS or sterile mycoplasma broth. A group of nonvaccinated specific-pathogen-free chickens at similar age were also exposed to aerosolization with M. gallisepticum strain Ap3AS and used as positive controls. Postmortem examination of the birds, performed 2 wk after challenge, revealed no significant difference in microscopic tracheal lesions or mucosal thicknesses between the ts-11-vaccinated field birds irrespective of their aerosolization treatment. However, both microscopic tracheal lesions and tracheal mucosal thicknesses of nonvaccinated challenged birds were significantly greater than those of ts-11 vaccinates. Hence, broiler breeders vaccinated in the field showed significant protection against virulent M. gallisepticum challenge even when no serum antibody was detected by rapid serum agglutination test. These results reveal that seroconversion detected by rapid serum agglutination test after ts-11 vaccination is not a reliable predictor of protection against M. gallisepticum infection. The possible significance of local antibody response and cell-mediated immunity against M. gallisepticum infection is discussed. 相似文献
14.
Christian Savard Fernando Alvarez Chantale Provost Younes Chorfi Sylvie D’Allaire Marie-Odile Benoit-Biancamano Carl A. Gagnon 《Canadian journal of veterinary research》2016,80(1):1-11
Vaccination is a useful option to control infection with porcine reproductive and respiratory syndrome virus (PRRSV), and several modified live-PRRSV vaccines have been developed. These vaccines have shown some efficacy in reducing the incidence and severity of clinical disease as well as the duration of viremia and virus shedding but have failed to provide sterilizing immunity. The efficacy of modified live-virus (MLV) vaccines is greater against a homologous strain compared with heterologous PRRSV strains. The objective of this study was to evaluate the efficacy of Fostera PRRS MLV vaccine in protecting against challenge with a heterologous field strain widely circulating in the swine herds of eastern Canada. Forty-six piglets were divided into 4 groups: nonvaccinated-nonchallenged; nonvaccinated-challenged; vaccinated-challenged; and vaccinated-nonchallenged. The animals were vaccinated at 23 d of age with Fostera PRRS and challenged 23 d later with a heterologous field strain of PRRSV (FMV12-1425619). Overall, the vaccine showed some beneficial effects in the challenged animals by reducing the severity of clinical signs and the viral load. A significant difference between nonvaccinated and vaccinated animals was detected for some parameters starting 11 to 13 d after challenge, which suggested that the cell-mediated immune response or other delayed responses could be more important than pre-existing PRRSV antibodies in vaccinated animals within the context of protection against heterologous strains. 相似文献
15.
The protective value of monovalent and bivalent adenovirus vaccines against pneumoenteritis was studied in fattening lambs. The monovalent vaccine was prepared from strain ORT/111 which is a sheep isolate, related to bovine adenovirus type 2. The bivalent vaccine contained virus strains ORT/111 and GY/14, which is a local isolate of ovine adenovirus type 1. After administration of monovalent vaccine higher titres of neutralizing antibodies (1:128–1:512) were found than after the bivalent vaccine (1:16–1:128).Following challenge with a homologous virus strain, the lambs vaccinated with monovalent vaccine remained healthy and did not shed the virus. Those vaccinated with the bivalent vaccine and challenged with GY/14 strain also remained healthy, but two out of five lambs shed virus in the faeces. Non-vaccinated challenged controls developed characteristic signs of the disease and shed the virus both in the nasal discharge and the faeces. From the results it can be concluded that experimental adenoviral pneumoenteritis of fattening lambs can be prevented by active immunization. 相似文献
16.
The efficacy of three commercial Mycoplasma gallisepticum (MG) immunizing agents-a bacterin, a recombinant fowlpox-MG vaccine, and a live F-strain vaccine-was compared in specific-pathogen-free hens in egg production. Three groups of 25 chickens were vaccinated with one of the vaccines at 10 wk of age and 25 birds were not vaccinated. At 25 wk of age (and approximately 50% egg production), 20 birds from each of the three vaccinated groups and 15 nonvaccinated controls were challenged with virulent R-strain via aerosol; the birds were necropsied and evaluated at 10 days post-challenge. The MG bacterin and live F-strain vaccinations were both protective and resulted in significant differences in air sac lesions, tracheal lesions, and ovarian regression compared to the nonvaccinated controls and the recombinant fowlpox-MG vaccine (P < or = 0.05). The evaluation of ovarian regression is a useful method of testing the efficacy of MG vaccines in laying hens. 相似文献
17.
Kelling CL Hunsaker BD Steffen DJ Topliff CL Abdelmagid OY Eskridge KM 《American journal of veterinary research》2005,66(10):1785-1791
OBJECTIVE: To evaluate protection against systemic infection and clinical disease provided by use of a modified-live noncytopathic bovine viral diarrhea virus (BVDV) type 1 vaccine in calves challenged with NY-1 BVDV. ANIMALS: 10 calves, 5 to 7 months of age. PROCEDURES: Calves were allocated (n = 5/group) to be nonvaccinated or vaccinated SC on day 0 with BVDV type 1 (WRL strain). Calves in both groups were challenged intranasally with NY-1 BVDV on day 21. Calves' rectal temperatures and clinical signs of disease were recorded daily, total and differential WBC and platelet counts were performed, and serum neutralizing antibody titers against NY-1 BVDV were determined. Histologic examinations and immunohistochemical analyses to detect gross lesions and distribution of viral antigens, respectively, were performed. RESULTS: After challenge exposure to NY-1 BVDV, nonvaccinated calves developed high rectal temperatures, increased respiratory rates, viremia, leukopenia, lymphopenia, and infection of the thymus. Vaccinated calves did not develop high rectal temperatures or clinical signs of respiratory tract disease. Vaccinated calves appeared to be protected against systemic replication of virus in that they did not develop leukopenia, lymphopenia, viremia, or infection of target organs, and infectious virus was not detected in peripheral blood mononuclear cells or the thymus. CONCLUSIONS AND CLINICAL RELEVANCE: The modified-live BVDV vaccine protected calves against systemic infection and disease after experimental challenge exposure with NY-1 BVDV. The vaccine protected calves against infection and viremia and prevented infection of target lymphoid cells. 相似文献
18.
Avian pathogenic Escherichia coli strains are associated with a variety of extraintestinal poultry diseases, including airsacculitis, colisepticemia, and cellulitis. A number of E. coli serotypes are associated with these diseases, although the most prevalent serotype is O78. Fimbrial proteins expressed by these strains appear to be important virulence factors, including type 1 fimbriae, P fimbriae, and curli. We have been working to develop an effective vaccine to protect chickens against these diseases. We have previously shown that an attenuated Salmonella typhimurium strain expressing O78 lipopolysaccharide provides protection against challenge with an O78 avian pathogenic E. coli strain. In this work, we have constructed an attenuated S. typhimurium that expresses both the O78 lipopolysaccharide and E. coli-derived type 1 fimbriae. In these studies, chickens were vaccinated at day of hatch and again at 2 wk of age. Birds were challenged at 4 wk of age. We found that the vaccine candidate provided significant protection against airsacculitis as compared to untreated controls or birds vaccinated with an attenuated S. typhimurium that did not express any E. coli antigens. In a separate experiment, challenged vaccinates showed significant weight gain compared to challenged nonvaccinates. We were not able to demonstrate protection against E. coli O1 or O2 serotype challenge, nor against challenge with wild-type S. typhimurium. 相似文献
19.
Coarse-spray (CS) administration of a commercial S1133 reovirus vaccine was evaluated in 1-day-old specific-pathogen-free broilers for prevention of clinical infection induced by intratracheal challenge with two enteric reovirus isolates. In Expt. 1, chickens were challenged at 4 days of age with either the 2408 or CO8 isolate. In Expt. 2, chickens were challenged at 7 days of age with either isolate. In Expt. 3, chickens were challenged at 3, 5, or 7 days of age with the 2408 isolate. In Expt. 1, vaccinated birds showed significant protection against challenge with either isolate at 4 days of age as measured by morbidity, mortality, gross lesions, and body weight. In Expt. 2, vaccinated birds showed greater protection against challenge at 7 days of age. In Expt. 3, resistance in vaccinated birds increased with time between vaccination and challenge. Vaccinated birds challenged at 3 days of age showed no significant protection, whereas vaccinated birds challenged at 5 or 7 days of age had increased resistance. This vaccine did not induce a drop in weight gain, morbidity, mortality, or microscopic lesions in the tendons. 相似文献
20.
Calves at the age of one month were vaccinated with a lyophilized vaccine against bovine trichophytosis, or with an avirulent vaccine against bovine trichophytosis (mfd by Bioveta, Ivanovice in Haná). Prophylactic doses of the vaccines (15 mil. CFU of production strain Trichophyton verrucosum per calf) were used for immunization, and doses 10 times, 100 times and 1000 times lower. The calves were revaccinated with the same doses in 12 days after the first vaccination. Twenty-eight days later since revaccination, the vaccinated calves and a group of control nonvaccinated calves was challenged epicutaneously with a virulent strain of T. verrucosum. The protectiveness of both vaccines implanted at doses of 2 x 15 mil. and 2 x 1.5 mil. CFU per test animal was very good. No dermal lesion were observed in the challenged calves of these groups, or if any, they were not clear and could be observed for a short time. If the vaccines were used diluted at a ratio 10(-2) (150 thousand CFU of production strain), trichophytic lesions persisting for the whole period of observation were found in four of the seven calves vaccinated with a lyophilized vaccine against bovine trichophytosis and in two of the eight calves implanted an avirulent vaccine after challenge. Mycotic lesions were formed after challenge in all test animals in the groups vaccinated with doses of 2 x 15 thousand CFU of production strain per calf. The extent of these lesions was practically the same as in all nonvaccinated controls--on the surface of infected skin the hair was shed and scales and crusts were formed. A challenge strain of T. verrucosum was cultivated from these lesions. 相似文献