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1.
Three experiments were conducted with calves in which, following intramuscular or intranasal vaccination with virulent or attenuated bovine herpesvirus 1, calves were protected against bovine herpesvirus 1 -- Pasteurella haemolytica challenge. Calves receiving low doses of vaccine had lower levels of antibody and greater evidence of virus replication upon challenge than those receiving higher doses. In contrast 11/13 unvaccinated controls had fibrino-purulent pneumonia following challenge. The immune response developed later in younger calves and those given low doses of vaccine. Neutralizing antibodies to bovine herpes-virus 1 were not found in nasal secretions, but were present in serum seven days after vaccination. Bovine herpesvirus 1 was isolated before challenge from nasal secretions of calves vaccinated intranasally or intramuscularly with virulent virus but not those vaccinated intramuscularly with vaccine virus. It was concluded that both routes of vaccination with either virulent or attenuated bovine herpesvirus 1 provided protection from challenge with homologous or heterologous bovine herpesvirus 1 and that live vaccines should contain at least 10(3) plaque forming units/dose for effective immunization.  相似文献   

2.
The safety, efficacy and duration of immunity of an improved oil-adjuvant vaccine against haemorrhagic septicaemia, containing inactivated cells of Pasteurella multocida serotype B:2,5, were tested in young buffalo calves in Pakistan. For safety testing, five buffalo calves were vaccinated intramuscularly with twice the normal dose, and six weeks later with a normal dose. Except for a transient rise in rectal temperature at six hours after the vaccinations, no systemic reactions were observed. The buffaloes remained in good condition and had a normal appetite. No local reactions were observed at the injection site. For efficacy testing two trials were carried out. In the first, buffalo calves were vaccinated intramuscularly either with two doses two-and-a-half months apart, or with a single dose, or left unvaccinated. They were challenged subcutaneously with virulent P multocida after eight, 13 or 15 months. After challenge at eight months the four buffaloes given two doses and the buffalo given one dose were protected, whereas the control animal developed the typical signs of the disease. After the challenges at 13 and 15 months, the vaccinated animals were still protected whereas the control animals died. In the second trial, buffalo calves were vaccinated intramuscularly either with two doses two months apart, or with a single dose at two months or left unvaccinated. The buffaloes were challenged after eight or 14 months. After challenge at eight months the four control animals died, whereas three of the four buffaloes given a single dose were protected. After challenge at 14 months, the three control animals died, whereas four of the five buffaloes given two doses and both the buffaloes given a single dose were protected. To test for cross-protection against the heterologous serotypes E:2,5 and B:3,4, groups of mice were vaccinated once or left unvaccinated. Four weeks later, the vaccinated and control groups were challenged with a dilution series of the different challenge cultures. The vaccine appeared to induce protection against challenge with different strains of serotypes B:2,5 and E:2,5 but not against strains of serotype B:3,4.  相似文献   

3.
A new genotype of bovine viral diarrhoea virus (BVDV), designated BVDV-2, has emerged in the last decade and in recent years the prevalence of BVDV-2 strains has increased. A vaccination-challenge study was carried out to determine the cross-protective efficacy of a commercial inactivated vaccine containing a BVDV-1 strain. A group of five BVDV-free calves was vaccinated twice and a second group of five calves served as negative controls. Two months after the first vaccination, all the calves were challenged intranasally with BVDV-2 strain BVD890. The clinical signs of disease, the changes in haematological variables and the level of viraemia were significantly less in the vaccinated group.  相似文献   

4.
A subunit vaccine in the form of immunostimulating complex (iscom) was prepared to contain the envelope glycoproteins of bovine herpesvirus type 1 (BHV-1). This iscom preparation was tested in a vaccination experiment on 4-month-old calves seronegative to BHV-1. In this experiment, four groups with three animals per group were used. Two groups were vaccinated with the iscom preparation twice, four weeks apart, one group with 50 micrograms and the other with 100 micrograms per calf. The third group received a commercial inactivated whole-virus vaccine applying the same vaccination program. The fourth group served as control. Two weeks after the second vaccination, all the animals were challenge-infected intranasally with a virulent BHV-1 strain and four days later with a virulent Pasteurella multocida--this in order to mimic hard field conditions. When exposed to challenge infection, all the animals vaccinated with the iscom were fully protected, i.e., no virus could be recovered from their nasal secretions and no clinical symptoms were recorded. In contrast, the animals vaccinated with the commercial vaccine, responded to challenge with moderate fever and loss of appetite, and virus was isolated from the nasal secretions. The animals in the control group developed severe clinical symptoms. In the sera of iscom-vaccinated animals, the virus neutralization titers reached levels of 1/3500 or higher.  相似文献   

5.
Peripheral blood lymphocytes (PBL) from non-vaccinated dogs and from dogs either vaccinated intramuscularly (IM) or subcutaneously (SC) with an inactivated rabies virus vaccine (Rabguard-TC, Norden Laboratories, Lincoln, NE) or intramuscularly with an attenuated rabies virus vaccine (Endurall-R, Norden Laboratories, Lincoln, NE) were exposed in vitro to rabies virus. Blastogenesis of PBL was measured by incorporation of 3H-thymidine into the DNA of proliferating cells in the presence of a suboptimal concentration of phytohemagglutinin (PHA). Following the first vaccination, there was no difference in the blastogenic response of lymphocytes from dogs vaccinated IM with either the inactivated or attenuated rabies virus vaccines. The inactivated rabies vaccine stimulated as great or greater blastogenic response when it was given SC. The PBL from non-vaccinated control dogs were not stimulated by rabies virus. Dogs vaccinated with the inactivated vaccine developed a lymphocyte blastogenic response to rabies virus following challenge with virulent street rabies virus. Nonvaccinated control dogs did not develop a lymphocyte blastogenic response to rabies virus following challenge with virulent street rabies virus.  相似文献   

6.
In order to assess the efficacy of a two‐step vaccination protocol with respect to foetal protection against transplacental infections with bovine virus diarrhoea virus (BVDV) with special attention to BVDV‐2 seronegative heifers were vaccinated with an inactivated BVDV‐1 vaccine and boostered with a modified live BVDV‐1 vaccine after 4 weeks. A second group was left unvaccinated as control. Between days 30 and 120 of pregnancy the heifers of both groups were intranasally challenged with a mixture of BVDV‐1 and ‐2. All heifers of the vaccinated group gave birth to nine clinically healthy, seronegative (precolostral) and BVDV‐free calves. In contrast in the control group four BVDV viraemic underdeveloped calves were born. Additionally, one calf was stillborn and another viraemic calf was not viable and died 2 days after birth. All six calves of the control group were viraemic with BVDV‐2. This study demonstrated for the first time that two‐step vaccination of breeding cattle with a modified live BVDV vaccine 4 weeks after application of an inactivated BVDV vaccine was capable of providing a foetal protection against transplacental infection with BVDV‐2.  相似文献   

7.
The efficacy of a bivalent inactivated vaccine against bluetongue virus (BTV) serotypes 2 (BTV-2) and 4 (BTV-4) was evaluated in cattle by general and local examination, serological follow-up, and challenge. Thirty-two 4-month-old calves were randomly allocated into 2 groups of 16 animals each. One group was vaccinated subcutaneously (s/c) with two injections of bivalent inactivated vaccine at a 28-day interval, and the second group was left unvaccinated and used as control. Sixty-five days after first vaccination, 8 vaccinated and 8 unvaccinated calves were s/c challenged with 1 mL of 6.2 Log10 TCID50/mL of an Italian field isolate of BTV serotype 2, while the remaining 8 vaccinated and 8 unvaccinated animals were challenged by 1 mL of 6.2 Log10 TCID50/mL of an Italian field isolate of BTV serotype 4. Three additional calves were included in the study and used as sentinels to confirm that no BTV was circulating locally. At the time of the challenge, only one vaccinated animal did not have neutralizing antibodies against BTV-4, while the remaining 15 showed titres of at least 1:10 for either BTV-2 or BTV-4. However, the BTV-2 component of the inactivated vaccine elicited a stronger immune response in terms of both the number of virus neutralization (VN) positive animals and antibody titres. After challenge, no animal showed signs of disease. Similarly, none of the vaccinated animals developed detectable viraemia while bluetongue virus serotype 2 and 4 titres were detected in the circulating blood of all unvaccinated animals, commencing on day 3 post-challenge and lasting 16 days. It is concluded that administration of the bivalent BTV-2 and BTV-4 inactivated vaccine resulted in a complete prevention of detectable viraemia in all calves when challenged with high doses of BTV-2 or BTV-4.  相似文献   

8.
Eight separate, but related experiments, were carried out in which groups of six calves were vaccinated with one of eight commercial vaccines. In each experiment the vaccinated calves were subsequently exposed to three calves infected with virulent bovine herpesvirus-1 (BHV-1). In each experiment, all infected donor calves developed a typical severe infectious bovine rhinotracheitis (IBR) infection and excreted virus in their nasal secretions of up to 10(8.00) TCID50/0.1 ml. One live BHV-1 gE-negative vaccine (A) and three modified live vaccines (B, C, D), administered intranasally, all protected against clinical disease. The calves vaccinated with one vaccine (C) also did not excrete virus in the nasal secretions, whereas the calves protected by vaccines A, B and D excreted virus in their nasal secretions but at low titres (10(0.66)-10(1.24) TCID50/0.1 ml). A fourth modified live vaccine (E), given intramuscularly, failed to prevent mild clinical disease in the calves which also excreted virus in the nasal secretions at titre of 10(1.00) TCID50/0.1 ml. An analogous result was given by the calves vaccinated with either of the two inactivated vaccines (F and G) or with a BHV-1 subunit vaccine (H). All calves developed mild clinical signs and excreted virus at titres of 10(2.20)-10(3.12) TCID50/0.1 ml. Calves vaccinated with C vaccine were subsequently given dexamethasone, following which virus was recovered from their nasal secretions. The virus isolates did not cause disease when calves were infected and appeared to be closely related to the vaccine strain.  相似文献   

9.
A total of 36 calves were used in three experiments to test the efficacy of a potassium thiocyanate extract of Pasteurella haemolytica in protecting against experimental pneumonia. In each of experiments A and B, 12 calves were divided into three equal groups. The first group was vaccinated with an aerosol of a potassium thiocyanate extract twice, two weeks apart; the second group was vaccinated subcutaneously once only with the same extract. The third group of calves in both experiments remained as unvaccinated controls. In experiment C, six calves were vaccinated intramuscularly and six were left as controls. Approximately one month after vaccination all calves were challenged with an aerosol of bovine herpesvirus 1 (isolate 108) followed in 4 d by an aerosol of P. haemolytica type A1 (the same strain from which the potassium thiocyanate extract had been made). Varying degrees of protection against subsequent development of experimental pneumonic pasteurellosis in cattle were seen in vaccinated calves as compared to control calves in these experiments. The results indicate that protection of cattle against pneumonic pasteurellosis may prove possible with a sub-cellular extract of P. haemolytica.  相似文献   

10.
A bovine herpesvirus-1 (BHV-1) vaccine expressing glycoprotein D, the form with the transmembrane anchor removed, was evaluated for inducing immunity in calves. The plasmid encoding gD of BHV-1 was injected three times to nine calves, using three animals for each of the following routes: intramuscularly (i.m.), intradermally (i.d.), or intranasally (i.n.). Three additional calves were given the plasmid vector only and served as unvaccinated controls. When calves were subjected to challenge infection with BHV-1, all vaccinated calves as well as the controls developed a typical severe form of infectious bovine rhinotracheitis. However, compared to the controls, the vaccinated calves showed earlier clearance of challenge virus. Moreover, the calves given the vaccine i.m. developed neutralizing antibody to BHV-1 between 21 and 42 days following the first injection of vaccine, whereas in calves vaccinated either i.d. or i.n., as well as the controls, antibody first appeared in their sera 14 days post-challenge infection.  相似文献   

11.
Field trials were carried out in calves using a live bovine respiratory syncytial (BRS) virus vaccine prepared from the attenuated BRS virus, strain rs-52. Two hundred seventy-five and 353 calves were vaccinated intranasally and intramuscularly, respectively. No undesirable postvaccinal reactions were observed in the vaccinated calves. Of the serum neutralizing (SN) antibody negative calves 89.7% (26/29) and 92.8% (90/97) developed SN antibody 1 month after intranasal and intramuscular vaccination, respectively. Most of the calves having SN antibody titers of 1:1 or 1:2 at the time of vaccination showed a significant increase in SN antibody titer. About 70% and 90% of the calves vaccinated intranasally and intramuscularly, respectively, maintained SN antibody for 6 months after vaccination. In a field trial, a natural BRS virus infection occurred about 5 months after the start of the trial. Ten of the 16 unvaccinated control calves showed respiratory symptoms due to BRS virus infection. On the contrary, all of the 68 vaccinated calves exhibited no symptoms at all, indicating efficacy of the vaccine.  相似文献   

12.
A standardized test was developed to compare the efficacy of Aujeszky's disease virus (ADV) vaccines under laboratory conditions. Per test 3 groups of 6 to 8 sero-negative pigs were used. The first vaccination was done at 10 weeks of age. One group was vaccinated once, another was vaccinated twice and the 3rd served as control. Pigs were challenge exposed to the virulent NIA-3 strain of ADV 12 weeks after the first vaccination. Apart from mortality, average periods of growth arrest, fever and virus shedding after challenge were used as parameters to evaluate vaccine efficacy. Two inactivated and 4 attenuated vaccines were tested. Two attenuated vaccine viruses were excreted after vaccination. Despite maximal standardization, a considerable variation still existed between the experiments in mortality and growth arrest periods of control pigs after challenge. However, the controls were always more severely affected than the vaccinated pigs. All vaccines except one were effective in preventing death after challenge, but none conferred complete protection. Most vaccinated pigs still lost weight, developed fever and shed virus after challenge. Revaccination after 3 or 4 weeks had little effect, particularly with the attenuated vaccines. The results of the present study indicate that 2 of the attenuated vaccines conferred the best protection, 1 attenuated vaccine appeared to be as effective as the 2 inactivated ones, and the 4th attenuated vaccine was least effective.  相似文献   

13.
In order to assess the efficacy of a two-step vaccination protocol with respect to foetal protection against transplacental infections with bovine virus diarrhoea virus (BVDV) with special attention to BVDV-2 seronegative heifers were vaccinated with an inactivated BVDV-1 vaccine and boostered with a modified live BVDV-1 vaccine after 4 weeks. A second group was left unvaccinated as control. Between days 30 and 120 of pregnancy the heifers of both groups were intranasally challenged with a mixture of BVDV-1 and -2. All heifers of the vaccinated group gave birth to nine clinically healthy, seronegative (precolostral) and BVDV-free calves. In contrast in the control group four BVDV viraemic underdeveloped calves were born. Additionally, one calf was stillborn and another viraemic calf was not viable and died 2 days after birth. All six calves of the control group were viraemic with BVDV-2. This study demonstrated for the first time that two-step vaccination of breeding cattle with a modified live BVDV vaccine 4 weeks after application of an inactivated BVDV vaccine was capable of providing a foetal protection against transplacental infection with BVDV-2.  相似文献   

14.
Summary

A standardized test was developed to compare the efficacy of Aujeszky's disease virus (ADV) vaccines under laboratory conditions. Per test 3 groups of 6 to 8 sero‐negative pigs were used. The first vaccination was done at 10 weeks of age. One group was vaccinated once, another was vaccinated twice and the 3rd served as control. Pigs were challenge exposed to the virulent NIA‐3 strain of ADV 12 weeks after the first vaccination. Apart from mortality, average periods of growth arrest, fever and virus shedding after challenge were used as parameters to evaluate vaccine efficacy.

Two inactivated and 4 attenuated vaccines were tested. Two attenuated vaccine viruses were excreted after vaccination. Despite maximal standardization, a considerable variation still existed between the experiments in mortality and growth arrest periods of control pigs after challenge. However, the controls were always more severely affected than the vaccinated pigs. All vaccines except one were effective in preventing death after challenge, but none conferred complete protection. Most vaccinated pigs still lost weight, developed fever and shed virus after challenge. Revaccination after 3 or 4 weeks had little effect, particularly with the attenuated vaccines. The results of the present study indicate that 2 of the attenuated vaccines conferred the best protection, I attenuated vaccine appeared to be as effective as the 2 inactivated ones, and the 4th attenuated vaccine was least effective.  相似文献   

15.
A comparison of intradermal (ID) versus intramuscular (IM) routes of pig vaccination with deleted Aujeszky's disease (AD) vaccine on the formation of specific postvaccinal and postchallenge humoral immune response was performed. The studies were carried out on 21 eight week-old piglets, divided into three groups--two experimental and one control of 7 piglets each. Animals of first two groups were vaccinated twice in 12 and 16 week of age with deleted, live attenuated AD vaccine Porcilis Begonia (Intervet). Group I was vaccinated with a dose of 2.0 ml (10(6.0) TCID50)) intramuscularly (IM) into neck muscles, and group II received 0.2 ml (10(5.0) TCID50) intradermally (ID) in neck area using needleless apparatus SERENA model SD 1-2 (Emplast, Italy). In group K (control) 2.0 ml PBS IM was used. Seventy days after the first vaccination all pigs were intranasally infected with a dose of 10(5.5) TCID50 of virulent Northern Ireland Aujeszky-3 (NIA-3) strain of Herpesvirus suis type 1 (SHV-1) by instilling 0.5 ml of virus suspension into each nostril. Specific humoral immune response was evaluated using seroneutralization (SN) test and gE-ELISA-Pseudorabies virus gpI Antibody Test Kit (Herd Chek Anti-PRV gpI), IDEXX Lab Inc (USA). It was found that challenge caused anamnestic reaction in both groups of vaccinated pigs, but postchallenge immune response was stronger in ID-vaccinated group--on 14 day post infection (dpi) SN antibody level was considerably higher than in IM-vaccinated group. The obtained results suggest that secondary immunological response after challenge is decidedly more effective in the range of evaluated parameters in animals vaccinated by ID route, which can be linked to, perhaps underestimated yet and seldom utilized, skin immunity mechanisms in specific prophylaxis of infectious diseases. Advantages and disadvantages of SN test and ELISA are also discussed.  相似文献   

16.
Four groups of calves were vaccinated with a glycoprotein E-negative vaccine for infectious bovine rhinotracheitis. Two groups of calves were vaccinated intramuscularly and challenged with a wild-type virus 14 and seven days after being vaccinated. The other two groups were vaccinated intranasally and similarly challenged after four and three days; an unvaccinated control group was also challenged. All four vaccination schedules reduced the incidence of clinical signs and the excretion of wild-type virus, and these reductions occurred as early as three days after the intranasal vaccination even in the absence of neutralising antibodies. Because of its marker characteristics, vaccination with this vaccine would not interfere with the detection of infected cattle during an outbreak, and it should therefore provide a useful tool for emergency vaccination campaigns.  相似文献   

17.
Foot-and-mouth disease (FMD) is a highly contagious and economically devastating vesicular disease of cloven-hoofed animals. In this study, we constructed and characterized the immune responses and vaccine efficacy conferred by the recombinant adenovirus co-expressing VP1 of FMDV and porcine interferon alpha as fusion protein (rAd-pIFNalpha-VP1). Six groups of female BALB/c mice each with 18 were inoculated subcutaneously twice 2-week intervals with the recombinant adenoviruses. The results showed that the levels of humoral and cell-mediated immune responses in the group inoculated with rAd-pIFNalpha-VP1 were significantly higher than those in the group inoculated with rAd-VP1+rAd-pIFNalpha (P<0.05). Then four groups of guinea pigs each with six were inoculated two times at 2-week intervals intramuscularly with rAd-pIFNalpha-VP1, commercial inactivated FMD vaccine, wild-type adenovirus (wtAd) or PBS, and the protective efficacy of rAd-pIFNalpha-VP1 was determined. The results indicated that all the guinea pigs vaccinated with rAd-pIFNalpha-VP1 as well as inactivated FMD vaccine were protected from FMDV challenge, even though the levels of neutralizing antibodies (1:32-1:40) of the animals vaccinated with rAd-pIFNalpha-VP1 was lower than that in the group inoculated with inactivated FMD vaccine (1:64-1:128). It demonstrated that the newly recombinant adenovirus rAd-pIFNalpha-VP1 might further be an attractive candidate vaccine for preventing FMDV infection in swine.  相似文献   

18.
Sixty-five calves of approximately three months of age and of mixed sex were vaccinated twice at four week intervals with either attenuated or inactivated infectious bovine rhinotracheitis vaccines. Following initial vaccination there was no demonstrable serum infectious bovine rhinotracheitis titer in any of the calves receiving the inactivated vaccine with 20.7% of the calves receiving the attenuated vaccines having demonstrable titers. Following a second administration of vaccine at eight weeks post-initial vaccination 63.9% of the calves receiving the inactivated vaccine had no demonstrable titer with 72.4% of the calves receiving the attenuated vaccine exhibiting a blood titer of four or greater.  相似文献   

19.
Several Aujeszky's disease virus (ADV) vaccination protocols of sows were evaluated with regard to the passive protection conferred on piglets in a recently built commercial farm. Three different groups of sows were vaccinated using a Bartha K-61 strain. One group received an inactivated vaccine during pregnancy and the other two groups received attenuated vaccines, either during pregnancy (day 65) or on the seventh day of lactation. At farrowing, sows vaccinated during lactation had lower seroneutralization titres than those vaccinated during pregnancy either with inactivated or attenuated vaccines. Accordingly, their piglets were the ones with lower levels of maternally transferred neutralizing antibodies. At 4 weeks of age, five piglets born of each group of sows were challenged intranasally with a neurotropic strain of ADV. Piglets born of sows vaccinated during pregnancy with inactivated and attenuated vaccines gained 1.50 kg bodyweight and 2.50 kg bodyweight during 7 days, respectively, and did not show clinical signs, while piglets from sows vaccinated during the previous lactation lost 0.60 kg and presented moderate to severe clinical signs of ADV. Vaccination of sows during pregnancy provided more protection against ADV for piglets than sow vaccination before mating. Piglets born from sows vaccinated with attenuated or inactivated vaccines did not present remarkable differences on protection.  相似文献   

20.
Pseudorabies virus (PRV) has been developed as a vaccine vector for expressing foreign immunogens. Porcine reproductive and respiratory syndrome (PRRS), caused by porcine reproductive and respiratory syndrome virus (PRRSV), continues to be a major problem to the pork industry worldwide. Many vaccine strategies have been developed to control the disease but most of them turn out to be unsuccessful. The objective of this research was to explore the feasibility of PRV-based vector vaccine in protection against PRRSV. A live attenuated vaccine-based PRV recombinant expressing the envelope protein GP5 of PRRSV was generated using recombinant DNA techniques. The Bartha-K61-derived recombinant virus, named rPRV-GP5, was shown to express PRRSV GP5 efficiently. Sixteen healthy piglets were assigned to one of four groups (one to four, four pigs per group). Animals in Groups 1 and 2 were each inoculated intramuscularly and intranasally with 10(7.0) PFU of rPRV-GP5 and its parent Bartha-K61, respectively; Group 3 were vaccinated intramuscularly with one-dose of PRRS inactivated vaccine; Group 4 was served as non-vaccinated control. One month later, all animals were all challenged with 10(6.5) TCID(50) of virulent PRRSV CH-1a. All animals in Groups 1 and 3 remained clinically healthy before and after challenge, with only a short period of fever (no more than 41 degrees C and 3 days), mild and gradually improving lung and kidney lesions, and short-term viremia (2 and 3 week, respectively) in spite of no detectable anti-PRRSV antibody before challenge. On the other hand, all animals in the other two groups showed evident clinical signs with higher temperatures (more than 41 degrees C) after challenge, and severe lung, kidney and spleen lesions and extended viremia (4 weeks). The results indicate that the rPRV-GP5 is safe for vaccinates and able to confer significant protection against clinical disease and reduce pathogenic lesions induced by PRRSV challenge in vaccinated pigs.  相似文献   

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