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1.
The purpose of this study was to determine whether intranasal/oral administration of probiotics can assist vaccination efficacy against an important swine pathogen, porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV). A controlled challenge trial was performed employing: (a) pigs vaccinated against PRRS and treated with a Lactobacillus casei, (b) pigs vaccinated against PRRS only, (c) pigs treated with L. casei only, and (d) pigs neither vaccinated against PRRS nor treated with L. casei. All pigs were challenged intranasally with a wild PRRSV strain. There was no difference in clinical signs or rectal temperature among the four groups. However, pigs that received L. casei gained significantly more weight than pigs that did not. Vaccinated pigs did not gain more weight than nonvaccinated pigs. Vaccinated groups had significantly fewer viraemic pigs on days post-challenge 4, 11 and 17 than nonvaccinated groups of pigs. There was no effect of probiotic on prevalence or duration of viraemia. Among viraemic pigs, there was no significant difference in mean log base(10) titer of PRRS virus among groups. These results suggest that orally administered L. casei does not affect immune response in such a way as to affect PRRS viraemia or nasal shedding. However, it still appears to provide significant benefit when administered during vaccination as indicated by the higher bodyweight gain following PRRS virus infection.  相似文献   

2.
The objective of this field study was to evaluate in an endemically porcine reproductive and respiratory syndrome (PRRS) virus-infected farm the reproductive performance of sows after their vaccination with a PRRS attenuated vaccine. In a farrow-to-finish pig farm with history of endemic PRRS virus infection, a total of 200 gilts and sows were used. They were divided in 2 groups of 100 animals. The first group was used as untreated controls, while the animals of the second group were vaccinated against PRRS virus using the attenuated Porcilis PRRS vaccine (Intervet International, The Netherlands) based on European strain. All health and reproductive parameters were recorded from the time of vaccination up to next weaning. No adverse systemic or local reactions or side effects relative to vaccination were noted. Compared to controls, vaccinated sows showed significantly improved farrowing rate (89% versus 78%) and a tendency for fewer returns to oestrus, particularly those at irregular intervals. Fewer sows farrowed prematurely and showed post-partum dysgalactia syndrome, but more live pigs were born and weaned in each litter after vaccination. It was concluded that vaccination of sows with Porcilis PRRS attenuated vaccine in farms with endemic PRRSV infection has beneficial effects on their health and fertility.  相似文献   

3.
Little is known about the safety and efficacy of extra-label use of the modified live porcine reproductive-and-respiratory syndrome (PRRS) virus vaccine in gestating sows. Our purpose was to determine the impact of vaccination on reproductive performance in 54 herds in Ontario, Manitoba (Canada) and the mid-western United States that were PRRS-positive, PRRS-negative, or concurrently affected by an outbreak of PRRS when initially vaccinated. Majority-vaccinated herds vaccinated ≥50% but <100% of sows at one time, and limit-vaccinated herds vaccinated <50% of sows at one time. Most majority-vaccinated herds did not vaccinate sows in late gestation, and none vaccinated during the initial PRRS outbreak. Numbers of pigs born alive and weaned decreased when pregnant sows were vaccinated. The effect of vaccination on productivity in the gestation following vaccination depended on the vaccination protocol.  相似文献   

4.
This study was conducted to investigate whether the co-delivery of DNA encoding porcine cytokines would enhance a protective immune response in pigs to a Pseudorabies virus (PRV; or Aujeszky’s disease virus) DNA vaccine. Aujeszky’s disease in pigs results in respiratory and nervous symptoms with important economic losses. To evaluate cytokine effects, eukaryotic expression vectors were constructed for porcine GM-CSF, IL-2 and IFN-γ. cDNA for each of these cytokines was inserted under the control of a CMV promoter in the pcDNA3 plasmid and cytokine expression was confirmed after DNA transfection in various mammalian cell cultures by bioassays (GM-CSF and IL2) and ELISA (IFN-γ). Pigs were vaccinated by single intramuscular injection with plasmid DNA encoding PRV gB and gD along with various combinations of cytokine plasmid constructs. Pig serum was tested for the production of antibody by isotype specific anti-PRV ELISA. Pigs were then challenged with the highly virulent PRV strain NIA3 on day 21 after vaccination. The survival and growth rate of pigs were monitored for seven days after the viral challenge. The co-administration of GM-CSF plasmid increased the immune response induced by gB and gD PRV DNA vaccine. This immune response was characterized by an earlier appearance of anti-PRV IgG2, a significantly enhanced anti-PRV IgG1 and IgG2 antibody response, a significantly decreased and shortened viral excretion in nasal swabs and an improved protection to the viral challenge. In contrast, the co-administration of porcine IL-2 or IFN-γ had no adjuvant effects. Our results thus demonstrate for the first time that the application of porcine GM-CSF gene in a DNA vaccine formulation can exert immuno-adjuvant and protective effects with single vaccination in the natural host pig against Aujeszky’s disease.  相似文献   

5.
The purpose of the study was to evaluate the short- and long-term immunity after intranasal vaccination in pigs with maternally derived antibodies (MDA). In two experiments, 10-week-old pigs with moderate MDA titres against Aujeszky's disease virus (ADV) were vaccinated intranasally with the Bartha strain of ADV to evaluate the protective immunity conferred at 2 weeks, 2 months and 4 months after vaccination. Protection was evaluated on the basis of severity of clinical signs, periods of fever and growth arrest, and duration and amount of virus excreted after challenge with a virulent ADV. During the first 2-3 weeks after vaccination, antibodies to ADV continued to decline as in unvaccinated control pigs. After that, antibody titres stabilized or gradually increased. At 2 weeks, 2 months and 4 months after vaccination, vaccinated pigs were significantly better protected than unvaccinated controls. The vaccinated pigs challenged 2 weeks after vaccination hardly developed any sign of disease. Mild signs of Aujeszky's disease and a growth arrest period of 5 days were observed in vaccinated pigs challenged 2 months after vaccination, whereas vaccinated pigs challenged 4 months after vaccination developed severe signs of disease and a growth arrest period of 13 days. Vaccinated pigs challenged 2 weeks after vaccination did not excrete challenge virus, and pigs challenged 2 or 4 months after vaccination excreted far less virus than unvaccinated controls. The results demonstrate that intranasal ADV vaccination of pigs with moderate MDA titres protected them from 2 weeks to at least 4 months after vaccination. Immunity steadily declined, however, after vaccination.  相似文献   

6.
OBJECTIVE: To document shedding of porcine reproductive and respiratory syndrome (PRRS) virus in mammary gland secretions of experimentally inoculated sows, to evaluate effects of vaccination during gestation on virus shedding during the subsequent lactation, and to evaluate shedding of PRRS virus in milk of sows in commercial herds. ANIMALS: 6 sows seronegative for PRRS virus were used for experiment 1, and 2 sows were retained for experiment 2. For experiment 3, 202 sows in commercial herds were used. PROCEDURE: In experiment 1, 2 sows were inoculated with PRRS virus, 2 sows were vaccinated with modified-live PRRS virus vaccine, and 2 sows served as control pigs. Mammary gland secretions were assayed for PRRS virus. In experiment 2, pregnant vaccinated sows from experiment 1 were vaccinated with another modified-live PRRS virus vaccine. Mammary gland secretions were assayed in the same manner as for experiment 1. For experiment 3, milk collected from 202 sows in commercial herds was assayed for PRRS virus. RESULTS: In experiment 1, PRRS virus was detected in mammary gland secretions of both vaccinated and 1 of 2 virus-inoculated sows. In experiment 2, virus was not detected in samples from either vaccinated sow. In experiment 3, all samples yielded negative results. CONCLUSIONS AND CLINICAL RELEVANCE: Na?ve sows inoculated late in gestation shed PRRS virus in mammary secretions. Previous vaccination appeared to prevent shedding during the subsequent lactation. Results for samples obtained from sows in commercial herds suggested that virus shedding in mammary gland secretions of such sows is uncommon.  相似文献   

7.
The objective of this study was to determine the effects of Mycoplasma hyopneumoniae and/or porcine reproductive and respiratory syndrome virus (PRRSV) vaccination on dually infected pigs. In total, 72 pigs were randomly divided into nine groups (eight pigs per group), as follows: five vaccinated and challenged groups, three non-vaccinated and challenged groups, and a negative control group. Single-dose vaccination against M. hyopneumoniae alone decreased the levels of PRRSV viremia and PRRSV-induced pulmonary lesions, whereas single-dose vaccination against PRRSV alone did not decrease nasal shedding of M. hyopneumoniae and mycoplasma-induced pulmonary lesions in the dually infected pigs. The M. hyopneumoniae challenge impaired the protective cell-mediated immunity induced by the PRRSV vaccine, whereas the PRRSV challenge did not impair the protective cell-mediated immunity induced by the M. hyopneumoniae vaccine. The present study provides swine practitioners and producers with efficient vaccination regimes; vaccination against M. hyopneumoniae is the first step in protecting pigs against co-infection with M. hyopneumoniae and PRRSV.  相似文献   

8.
One month prior to breeding, sows were vaccinated with an attenuated pseudorabies virus vaccine or challenged with a field strain of pseudorabies virus. A third group of sows were not vaccinated or challenged before breeding. Pigs from these sows were vaccinated at 3, 6, or 12 weeks of age and challenged with virulent virus three weeks later. One pig from each litter served as an unvaccinated, unchallenged control. Serum neutralization titers of these pigs were monitored from birth until 22 weeks of age. Titers of the sows were monitored through breeding, gestation and farrowing. The maximum prefarrowing anti-pseudorabies virus titer in the field virus challenged sows occurred four weeks following challenge. A significant decline in titers occurred at farrowing. Titers rose from one week postfarrowing and then declined. Titers in the field virus infected sows were consistently two to threefold greater than those of the vaccinated sows. The maximum prefarrowing anti-pseudorabies virus titer in the vaccinated sows occurred six weeks following vaccination. The geometric mean titer in these sow's then decreased and increased for two weeks after farrowing. The results in the pigs can be summarized as follows: Pigs from control sows had a greater serological response following field virus challenge than following vaccination with a modified live virus. Pigs from control sows responded serologically to vaccination at 3, 6 and 12 weeks of age. Pigs from control sows which were challenged at 6, 9 and 15 weeks of age had similar antibody responses. Pigs from vaccinated sows had no increase in titer following vaccination at three and six weeks of age. Titers increased when these pigs were vaccinated at 12 weeks of age. There was no significant increase in mean titers of pigs from challenged sows following vaccination at 3, 6 and 12 weeks of age. Vaccinated pigs from control and vaccinated sows had a secondary response following challenge three weeks after vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
The pharmacokinetics of intramuscularly administered ceftiofur crystalline‐free acid (CCFA) were determined in pigs that were clinically healthy (n = 8), vaccinated with a Porcine reproductive and respiratory syndrome modified live virus (PRRS MLV) (n = 10), challenged with wild‐type porcine reproductive and respiratory syndrome virus (PRRSv) VR‐2385 (n = 10), or vaccinated with PRRS MLV and later challenged with wild‐type PRRSv VR‐2385 (n = 10). Animals were given a single dose of CCFA intramuscularly at 5 mg/kg body weight. Blood was collected at 0 (pretreatment), 0.25, 0.5, 1, 6, 12, 24, 48, 96, 144, 192, and 240 h postinjection. Plasma was analyzed using liquid chromatography‐mass spectrometry. Plasma concentration–time curves for each group were evaluated with noncompartmental modeling. When compared to control animals, those receiving the PRRSv wild‐type challenge only had a lower AUC0‐last, higher Cl/F, and higher Vz/F. The PRRSv wild‐type challenge only group had the longest T1/2λ. The Cmax did not differ among all four treatments. Control animals had no statistically significant differences from animals vaccinated with PRRS MLV alone or animals vaccinated with PRRS MLV and later challenged with wild‐type PRRSv. Our results suggest that PRRSv wild‐type infection has the potential to alter CCFA pharmacokinetics and PRRS MLV vaccination may attenuate those changes.  相似文献   

10.
The aim of the present study was to investigate influences of threonine and tryptophan supplementation (TTS) on immune response of growing pigs inoculated with modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine. Twenty growing barrows (Landrace × Yorkshire) were randomly assigned to four groups according to the PRRS vaccination and TTS. Serum samples were collected from all pigs at days 0, 7, 14, 21, 28, 35, 49 post‐vaccination (day 0 defined as the day of vaccination). Pigs were euthanized and samples collected at day 49 post‐vaccination. The results showed that TTS tended to increase weight gain and average daily gain (ADG) of pigs (P < 0.1). PRRS vaccine enhanced serum PRRSV‐specific antibody, serum virus neutralizing (SVN) antibody and interferon‐γ, interleukin (IL)‐10 and IL‐1β concentrations (P < 0.05). The expression of TLR3 and TLR7 mRNA in lymph nodes were higher in TTS than in the control group after PRRS vaccine inoculation (P < 0.05). TTS diet mitigated lung damage which is induced by PRRS vaccination from microscopic evaluation. These results suggest that dietary TTS could improve growth performance of growing pigs, which may be ascribed to the improved immune response and mitigated lung damage.  相似文献   

11.
Oral microencapsulated Mycoplasma hyopneumoniae vaccines were tested for their ability to prevent mycoplasmal pneumonia in pigs. Eighteen four-week-old specific pathogen free pigs were divided into six groups of three. Each pig of groups 1 to 4 was inoculated intramuscularly with formalin-inactivated M hyopneumoniae in adjuvant and boosted orally 14 days later with four different microencapsulated vaccine microspheres. Group 5 was used as a positive control. All 15 pigs of groups 1 to 5 were challenged at 28 days after the first vaccination by an intratracheal inoculation of pneumonic lung suspension. The three pigs of group 6 were used as a negative control. All four vaccinated groups showed some protection when challenged, but the protection was more solid in pigs boosted with vaccine D (group 4) which contained less porcine serum in the microsphere. The study indicates that oral vaccination with M hyopneumoniae could play a role in prevention and eradication of mycoplasmal pneumonia in the pig.  相似文献   

12.
Glycoproteins B (gB), gC and gD of pseudorabies virus (PRV) have been implicated as important antigens in protective immunity against PRV infection. As cell-mediated immunity plays a major role in this protective immunity, we determined the significance of these glycoproteins in the actual induction of cell-mediated immunity. We vaccinated pigs with plasmid DNA constructs coding for gB, gC or gD and challenged them with the virulent NIA-3 strain of pseudorabies virus. Vaccination with plasmid DNA coding for gB induced the strongest cell-mediated immune responses including cytotoxic T cell responses, whereas plasmid DNA coding for gD induced the strongest virus neutralising antibody responses. Interestingly, vaccination with gB-DNA reduced virus excretion early after challenge infection while vaccination with gC-DNA or gD-DNA did not.This is the first study to demonstrate that DNA vaccination induces cytotoxic T cell responses in pigs and that cell-mediated immunity induced by vaccination with gB-DNA is important for the reduction of virus excretion early after challenge infection.  相似文献   

13.
为研制用于治疗和预防猪繁殖与呼吸综合征的高免血清,选取健康育肥猪作为免疫接种对象,用猪繁殖与呼吸综合征灭活苗和弱毒苗作基础免疫和强化免疫,通过优化免疫程序,制备出抗猪繁殖与呼吸综合征高免血清,并进行了临床治疗试验,结果总有效率为86.67%。表明采用这种方法制备猪繁殖与呼吸综合征高免血清是安全有效、切实可行的。  相似文献   

14.
Objective-To determine whether a novel optimized plasmid carrying the porcine growth hormone-releasing hormone (GHRH) wild-type cDNA administered at a lower dose was as effective at eliciting physiologic responses as a commercial GHRH plasmid approved for use in Australia. Animals-134 gilts. Procedures-Estrus was synchronized and gilts were bred. Pregnant gilts were assigned to 2 treatment groups (40 gilts/group) or 1 untreated control group (24 gilts). Gilts in one of the treatment groups received the commercial GHRH plasmid, whereas gilts in the other treatment group received a novel optimized GHRH plasmid; both plasmids were administered IM in the right hind limb, which was followed by electroporation. Sow and litter performance were monitored for the 3 gestations after treatment. Results-A significant increase in insulin-like growth factor-I concentrations, decrease in perinatal mortality rate, increase in the number of pigs born alive, and increase in the weight and number of pigs weaned were detected for both groups receiving the GHRH-expressing plasmids, compared with values for the control group. Additionally, there was a significant decrease in sow attrition in GHRH-treated females, compared with attrition in the control group, during the 3 gestations after treatment. Conclusions and Clinical Relevance-Both of the GHRH plasmids provided significant benefits for sow performance and baby pig survivability for pregnant and lactating sows and their offspring during the 3 gestations after treatment, compared with results for untreated control gilts. Use of a novel optimized plasmid reduced the effective plasmid dose in these large mammals.  相似文献   

15.
The period during which pigs are protected after vaccination is important for the successful usage of a marker vaccine against classical swine fever virus (CSFV) in an eradication programme. In four animal experiments with different vaccination-challenge intervals we determined the duration of protection of an E2 subunit marker vaccine in pigs after a single vaccination. Unvaccinated pigs were included in each group to detect transmission of the challenge virus.Three groups of six pigs were vaccinated once and subsequently inoculated with the virulent CSFV strain Brescia after a vaccination-challenge interval of 3, 51/2, 6 or 13 months. All vaccinated pigs, 16 out of 18, with neutralising antibodies against CSFV at the moment of challenge, 3, 51/2, 6 or 13 months later, survived, whereas unvaccinated control pigs died from acute CSF or were killed being moribund. A proportion of the vaccinated pigs did however develop fever or cytopenia after challenge and two vaccinated pigs were viremic after challenge. Virus transmission of vaccinated and challenged pigs to unvaccinated sentinel pigs did not occur in groups of pigs which were challenged 3 or 6 months after a single vaccination. Two out of eight vaccinated pigs that were found negative for CSFV neutralising antibody at 13 months after vaccination died after subsequent challenge.The findings in this study demonstrate that pigs can be protected against a lethal challenge of CSFV for up to 13 months after a single vaccination with an E2 subunit marker vaccine.  相似文献   

16.
A trial was carried out with HYORESP® a Mycoplasma hyopneumoniae (M. hyo) vaccine in order to confirm the benefit of vaccination under field conditions in a commercial industrial farrow‐ to‐finish unit, contaminated with M. hyo. Infection with M. hyo was confirmed through positive blood and colostrum samples [enzyme‐linked immunosorbent assay (ELISA) test] combined with positive gross lesions of the lung at slaughter. Two different vaccination schedules were tested. Pigs were randomly allocated to three groups: control non‐vaccinated group (n=130, given a placebo injection at 3, 25 and 70 days of age); early vaccinated group (n=128, given vaccination at 3 and 25 days of age and a placebo at 70 days of age); late vaccinated group (n=132, given a placebo at 3 and 25 days of age and vaccination at 70 days of age). Both growth rate and feed conversion ratio were significantly (P < 0.05) improved in the vaccinated groups compared with the control group. The lung lesion score was also significantly (P < 0.05) improved in both vaccinated groups. In this trial, it was clearly demonstrated that vaccination is highly effective in improving performance in pig units infected with M. hyo. The improvement in the feed conversion ratio in the vaccinated groups was especially impressive: – 0.411 (13% improvement) in the group vaccinated twice at 3 and 25 days of age; – 0.162 (5% improvement) in the group vaccinated once at 70 days of age. Performances were better when two shots were given early in life compared with one shot later – probably due to an infection taking place rather early in life for most of the pigs. Moreover, a significant reduction in the cost of supportive (injectable) medication was noticed in vaccinated pigs. In conclusion, HYORESP® proved to be a very efficacious tool to control M. hyo in infected herds with its remarkable flexibility that allows the vaccination schedule to be adapted to the specific field conditions.  相似文献   

17.
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   

18.
Groups of pigs vaccinated with an inactivated bivalent vaccine containing porcine parvovirus (PPV) and pseudorabies virus (PRV) developed geometric mean titers (GMT) of humoral antibody for each of the viruses as high or slightly higher than those of other groups of pigs that were vaccinated with inactivated monovalent vaccines containing one or the other of the same viruses. An increase in GMT after challenge exposure of vaccinated pigs to live virus indicated that vaccination did not prevent virus replication. However, an indication that replication was less extensive in vaccinated pigs was provided by the following. Although neither vaccinated nor nonvaccinated (control) pigs had clinical signs after exposure to the live PPV, the effect of vaccination was evident by the fact that GMT were higher in nonvaccinated pigs after exposure than they were in vaccinated pigs. Conversely, all pigs exposed to live PRV had clinical signs, but these signs varied between mild-to-moderate and transient for vaccinated pigs to severe and fatal for nonvaccinated pigs.  相似文献   

19.
Objective To investigate the protective efficacy of a pool of denatured membrane protein antigens of Mycoplasma hyopneumoniae (J strain) in the molecular size range 70 to 85 kDa (F3 antigen) in combination with adjuvants for pigs challenged with M hyopneumoniae .
Design A vaccine efficacy experiment with assessment of serum and respiratory tract antibody responses.
Procedure F3 antigens were emulsified with five different adjuvants. To groups of three pigs per vaccine, four vaccines were given by intramuscular injection, and two vaccines, including one of those given intramuscularly, were given by intraperitoneal injection.
Results Compared to six unvaccinated pigs, animals vaccinated with F3 antigen displayed significantly reduced pneumonia (54% reduction in mean lung score) following experimental challenge. Analysis of post-vaccination, pre-challenge IgG and IgA ELISA antibody absorbances in serum and respiratory tract washings revealed no correlation with lung score. Six weeks after challenge, pigs previously vaccinated intramuscularly mostly demonstrated greater IgG and IgA responses in respiratory tract washings, and greater IgG serum antibody responses, than those vaccinated by intraperitoneal injection.
Conclusion Pigs vaccinated with M hyopneumoniae antigens in the molecular size range of 70 to 85 kDa showed a significant reduction in lung lesions compared with unvaccinated control animals after experimental challenge. IgG and IgA antibody concentrations in serum and respiratory tract washings after vaccination do not provide a useful prognostic indicator of protection from enzootic pneumonia.  相似文献   

20.
Two commercial Aujeszky's disease vaccines, a modified killed vaccine and a sub-unit vaccine, both carrying a deletion of glycoprotein-I, were evaluated in pigs. Each vaccine was administered to two groups of four pigs, twice at 4-week intervals, with two pigs held as unvaccinated controls. All pigs were challenged with a New Zealand field isolate of Aujeszky's disease virus 3 weeks after the second vaccination. The results indicate that the sub-unit vaccine was able to protect pigs against clinical Aujeszky's disease much better than the pigs vaccinated with the modified killed vaccine when challenged with a virulent virus. However, the amount and the duration of virulent virus excretion following challenge was greater with the sub-unit vaccine than the modified killed vaccine. Pigs vaccinated with the sub-unit vaccine were shown to be latently infected following challenge. Latent infection was demonstrated by excretion of Aujeszky's disease virus from the nasal cavity after dexamethasone treatment and seroconversion of a sentinel in contact pigs to Aujeszky's disease virus.  相似文献   

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