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1.
Foot-and-mouth disease (FMD) is an economically important disease of cloven-hoofed animals. The multiplicity of FMDV serotypes in animals poses a central problem in the policy of vaccination and is of much concern to health authorities. Hence it is the practice of vaccination with polyvalent vaccine for prophylactic measure. In the present report, we analysed the early antibody responses elicited by FMDV quadrivalent (FMDV O, A, C and Asia 1 serotypes) double emulsion (Montanide ISA 206) vaccines in cattle. We observed variations between various viral serotypes in eliciting early antibody response although neutralizing antibody response against all the four serotypes were detected as early as fourth day following vaccination. The duration of immunity also appeared to maintain for long period. The neutralizing antibody titres were maintained well above 2log(10) even after 6 months of vaccination irrespective of serotypes. Thus, allows the possibilities of two vaccinations per year for the maintenance of herd immunity.  相似文献   

2.
Protection against foot-and-mouth disease (FMD) and ability to transmit FMD virus to susceptible contact animals were studied in cattle vaccinated three times in annual field campaigns with the Dutch trivalent vaccine. Eighty vaccinated cattle and 16 susceptible controls were intranasally exposed to an aerosol containing a homologous FMD challenge virus (O1 BFS, A10 Holland or C1 Detmold) or a heterologous virus (A5 Modena or C1 Modena). The day after exposure, vaccinated cattle were stabled individually with an FMD-susceptible contact. All cattle challenged with an homologous virus strain at one year (20 head), at two years (10 head) and at three years (30 head) after the last vaccination were protected against the development of clinical signs of disease; one, zero and five cattle of these groups, respectively, transmitted virus to their contacts. In each group, approximately two out of three exposed cattle had virus-positive oropharyngeal fluid samples and seroconverted. The amount of virus recovered from probang samples increased with the time since the last vaccination. Mean antibody titres of cattle that had not been vaccinated for three consecutive years did not change significantly over the last two-year period. All 10 cattle challenged with the vaccine strain-related C1 Modena virus were protected against clinical disease, whereas three out of 10 challenged with the heterologous A5 Modena strain virus one year after the last vaccination contracted FMD and transmitted the virus. Five others (four in the C1 group and one in the A5 group) spread the virus to their contacts.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Small ruminants play an important role in the epidemiology of Foot-and-Mouth Disease (FMD). Small ruminants are vaccinated with one-half or one-third of cattle dose of oil-based or aqueous vaccines respectively. The extinction antigen payload in vaccine for protection in small ruminants is poorly studied. FMD seronegative Nellore sheep (n=30) and Osmanabadi goats (n=30) were vaccinated with different payloads of O(1) Manisa vaccine (0.45-5 μg). Vaccinated and sero-negative unvaccinated sheep (n=6) and goats (n=6) were challenged intradermally into the coronary band with O(1) Manisa virus. The sheep and goats were monitored for signs of FMD and samples were collected for measuring viraemia and virus associated with nasal swabs and probang samples. Clotted blood was collected for serology. Vaccines containing antigen payload up to 0.94 μg protected sheep and goats against challenge. Sheep and goats vaccinated with 0.45 μg antigen payload were poorly protected against challenge. An antigen payload of 0.94 μg was sufficient to offer complete protection and also absence of carrier status. Sheep and goats with no vaccination or with poor sero conversion to vaccination showed sub-clinical infection and became carriers. The results of the study suggest that vaccination offers protection from clinical disease even at a low payload of 0.94 μg and hence one-half of cattle dose of the oil-based vaccine formulations is sufficient to induce protective immune response in sheep and goats. Since no live virus could be isolated after 5 days post challenge from the nasal swab or probang samples even though viral RNA was detected, the risk of these animals transmitting disease was probably very low.  相似文献   

4.
Inactivated vaccines for heartwater prepared with the commercially acceptable Montanide ISA 50 (ISA 50) adjuvant were field tested in Boer goats in Botswana, Angora goats in South Africa, and Merino sheep in Zambia and Zimbabwe. Two vaccines, one made using the Zimbabwean Mbizi isolate and the other using the respective local field isolate (Sunnyside in Botswana; Bathurst in South Africa; Lutale in Zambia), were tested at each site, except in Zimbabwe where only the Mbizi vaccine was tested. Compared with unvaccinated animals, the Mbizi vaccine significantly protected goats and sheep against field Amblyomma tick challenge in Botswana, Zambia and Zimbabwe (P = 0.018, 0.002 and 0.017, respectively), but failed to protect Angora goats in South Africa. However, in South Africa the vaccine prepared using the local field isolate Bathurst, induced significant protection (P=0.008). The vaccines containing the local isolates at all other sites were less protective than the Mbizi vaccine. The Mbizi inactivated vaccine also significantly protected 17 of 21 cattle (P = 0.05) against heartwater challenge from field ticks in Zimbabwe. Against the same challenge only 7 of 21 unvaccinated control cattle survived.This study demonstrates that heartwater is a major constraint to upgrading livestock in endemic areas, and caused an overall mortality of 77.6% in naive sheep and goats (97 of 125 died) and 67% in cattle (14 of 21 died). In contrast, the vaccine had a protective effect by reducing the overall mortality in sheep and goats to 54.3% (113 of 208 died) and to 19% in cattle (4 of 21 died).  相似文献   

5.
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6.
A monoclonal antibody, 3BIgG, against the prokaryotically expressed foot-and-mouth disease virus (FMDV) non-structural protein (NSP) 3B was obtained. The 3BIgG-sepharose conjugant (3BmAb-6BFF) was prepared by adding the purified 3BIgG into epoxy-activated sepharose 6BFF, incubating with the inactivated FMDV, and then removing the sepharose by centrifugation. The vaccine was made from the supernatant emulsified with oil-adjuvant ISA206. Ten guinea pigs, 26 pigs and six cattle were vaccinated, and a vaccination control group was included without treatment with 3BmAb-6BFF. After 28 days, 9/10 pigs challenged with FMDV were protected, this result was the same as the control group, indicating that the vaccine potency was not reduced after treatment with 3BmAb-6BFF. The other animals were vaccinated weekly for nine weeks, and serum samples were collected to detect 3ABC-antibody titers. The results showed that 3ABC-antibody production was delayed and the positive antibody rates were lower when vaccination was carried out using vaccines treated with 3BmAb-6BFF compared with untreated vaccines. The findings of this study suggest that it is possible to reduce NSPs using a mAb-sepharose conjugant in FMD vaccines without reducing their efficacy.  相似文献   

7.
Four groups of 9 cattle each were vaccinated with 10, 50, 250, or 1,250 micrograms of foot-and-mouth disease (FMD) virus A12 VP1 fusion protein that was produced in Escherichia coli and emulsified in an oil adjuvant. The groups given the 10 and 50 micrograms of antigen were revaccinated at 15 weeks and were challenge exposed at 30 weeks; 5 of 9 and 7 of 9 cattle, respectively, were protected from FMD virus infection. The remaining 2 groups, vaccinated with 250 or 1,250 micrograms of antigen, were revaccinated at 32 weeks and were challenge exposed at 45 weeks; 8 of 9 and 9 of 9 cattle, respectively, were protected. The results indicated that the biosynthetic polypeptide FMD vaccine was effective using vaccination intervals frequently followed with conventional whole-virus vaccines.  相似文献   

8.
Four groups of six cattle were vaccinated from two to five times at 6 month intervals with two different trivalent FMD vaccines licensed in the given year. The FMDV type A strains in the vaccines designated A5F and A5B were closely related. Three months after the last vaccination the cattle were challenged by contact with animals inoculated with the original field strain A5B. The inoculated animals developed typical FMD symptoms with vesicles in the mouth and on the feet. Those cattle which had received vaccines that did not contain strain A5B also became severely sick, even after five vaccinations. Animals vaccinated twice with type B containing vaccine were also not completely protected. A safe protection can obviously only be achieved for fairly short periods of time if vaccine and challenge strain are homologous. It is proposed to change the rules of licensing, to speed up the procedure to vaccinate in cases of outbreaks. The need for further research, especially into improving vaccines, is stressed.  相似文献   

9.
In this study, we investigated whether Cedivac-FMD, an emergency vaccine against foot-and-mouth disease (FMD), is suitable for use conjointly with a screening program intended to confirm freedom from disease in vaccinated herds based on evidence of virus replication in vaccinates. Different sets of sera were tested using the Ceditest FMDV-NS ELISA for the detection of antibodies against non-structural proteins (NSPs) of FMD virus. During a vaccine safety study, serum samples were collected from 10 calves, 10 lambs and 10 piglets following administration of a double dose and a repeat dose of high payload trivalent Cedivac-FMD vaccine. All serum samples collected both 2 weeks following the administration of a double dose as well as those collected 2 weeks after the single dose booster (given 2 weeks after the double dose) were negative in the Ceditest FMDV-NS ELISA. In a series of vaccine potency experiments, serum samples were collected from 70 vaccinated cattle prior to and following exposure to infectious, homologous FMD virus. When testing cattle sera collected 4 weeks after vaccination with a regular dose of monovalent >6 PD(50) vaccines, 1 of 70 animals tested positive in the NSP antibody ELISA. After infection with FMD virus, antibodies to NSP were detected in 59 of 70 vaccinated cattle and 27 of 28 non-vaccinated control animals within 7 days. Cedivac-FMD vaccines do not induce NSP antibodies in cattle, pigs or sheep following administration of a double dose or a repeat dose. FMD-exposed animals can be detected in a vaccinated group within 7-14 days. Because Cedivac-FMD does not induce NSP antibodies, the principle of 'marker vaccine' applies.  相似文献   

10.
A single dose of foot-and-mouth disease (FMD) virus protein 1 (VP1) peptide, expressed in Escherichia coli as a fusion protein with 190 amino acids (AA) of the LE' protein of the tryptophan operon of E coli, elicited an immune response in steers sufficient to withstand the challenge of exposure to animals with acute FMD. The 58-micrograms dose of viral peptide, composed of a segment of the VP1 from the A12 strain (A12) of FMD virus (FMDV; A12-32dimer) in a tandem repeat configuration of AA137 through 168 and emulsified with oil adjuvant, elicited a serologic response in cattle equivalent to that obtained using conventional whole virus vaccines. Two groups of swine were vaccinated, 1 with the A12-32dimer as used in cattle and 1 with AA131 through 157 from VP1 of the A24 strain (A24) of FMDV (A24-peptide), expressed in the same system as A12-32dimer, but as a single copy per molecule. In swine, the 58-micrograms dose of the A12-32dimer repeated at 28 days was an effective immunogen; all swine were protected against A12 and, in addition, the vaccine protected 50% of the swine against A24. The 29-micrograms dose of A24-peptide, administered according to the same schedule, elicited protection against A24 in 50% of the vaccinates and, in addition, protected 25% of those vaccinates against A12. The serologic response elicited by A12-32dimer against A24 virus was considerably greater than the response elicited by A24-peptide against A12 virus. The evidence of multiple immunogenic epitopes between AA131 and AA168 was evaluated.  相似文献   

11.
Foot-and-mouth disease (FMD) is endemic in Kenya and has been well studied in cattle, but not in pigs, yet the role of pigs is recognised in FMD-free areas. This study investigated the presence of antibodies against FMD virus (FMDV) in pigs sampled during a countrywide random survey for FMD in cattle coinciding with SAT 1 FMDV outbreaks in cattle. A total of 191 serum samples were collected from clinically healthy pigs in 17 districts. Forty-two of the 191 sera were from pigs vaccinated against serotypes O/A/SAT 2 FMDV. Antibodies against FMDV non-structural proteins were found in sera from 30 vaccinated and 71 non-vaccinated pigs, altogether 101/191 sera (53 %), and 91 % of these (92/101) also had antibodies measurable by serotype-specific ELISAs, predominantly directed against SAT 1 with titres of 10–320. However, only five high titres against SAT 1 in vaccinated pigs were confirmed by virus neutralisation test (VNT). Due to high degree of agreement between the two ELISAs, it was concluded that positive pigs had been infected with FMDV. Implications of these results for the role of pigs in the epidemiology of FMD in Kenya are discussed, and in-depth studies are recommended.  相似文献   

12.
There has been an increasing interest in finding new formulations that qualify as vaccine adjuvants, which must be safe, stable, and have the capacity to stimulate a strong immune response. In this study, a basic formulation of a water-in-oil-in-water (W/O/W) adjuvant CV13 was developed, and ginseng stem-leaf saponins (GSLS) were added as an immune booster into oil phase. The physicochemical properties of the adjuvant were tested. Furthermore, the immune activity and the adjuvant effects, as indicated by the foot-and-mouth disease virus (FMDV) antigen were evaluated. The results showed that CV13 was similar in appearance to ISA 206 and could package FMDV antigen into a stable W/O/W emulsion. The FMD vaccine prepared with CV13 alone or CV13 containing GSLS achieved pharmaceutical characteristics comparable to a vaccine prepared with ISA 206, moreover the structural stability of the CV 13 vaccine was found to be better. Mice that were immunized with the FMD vaccine prepared with CV13 containing GSLS presented a significantly higher LPBE antibody titer and splenocyte proliferation rate than those immunized with a vaccine prepared with CV13 alone (p < 0.05). In addition, there was no significant difference between the groups that were immunized with FMD vaccine prepared with CV13 containing GSLS and ISA206 in terms of cellular and humoral immune response. In this paper, CV13 containing GSLS shows excellent immunologic adjuvant effect in mice model, and this new adjuvant may provide a potential choice for FMD vaccine production in the future.  相似文献   

13.
Six of the seven known serotypes of foot-and-mouth disease (FMD) virus occur in Africa. This paper describes the results of a population-based cross-sectional study of the seroprevalence of FMD and the persistence of the virus in cattle herds and associated sheep flocks in the Adamawa province of Cameroon. Antibody titres measured by the virus neutralising test indicated that serotypes O, A and SAT2 viruses had been circulating in the province. The estimates of apparent seroprevalence in cattle herds, based on five juvenile animals (eight to 24 months old) per herd, were 74.8 per cent for serotype SAT2, 30.8 per cent for serotype A and 11.2 per cent for serotype O, indicating recent exposure; the estimates based on animals more than 24 months of age were 91.1 per cent for SAT2, 83.6 per cent for A and 34.2 per cent for serotype O. Epithelial and oropharyngeal samples were collected from cattle and small ruminants, cultured and typed by ELISA; serotypes A and SAT2 were isolated from both types of sample. The herd-level estimate of apparent prevalence of probang-positive herds was 19.5 per cent and the animal-level estimate of apparent prevalence was 3.4 per cent. The geographical distribution of the seropositive herds based on juveniles suggested that recent SAT2 exposure was widespread and particularly high in the more northern and western parts of the province, whereas recent exposure to serotype A was patchy and more concentrated in the south and east. This distribution corresponded very closely with the distribution of herds from which virus was recovered by probang, indicating recent exposure or infection. No serotype O viruses were recovered from cattle, and the distribution of seropositive herds suggested very localised recent exposure. The apparent prevalence of probang-positive animals declined with the age of the animal and the period since the last recorded outbreak in the herd.  相似文献   

14.
Marek's disease virus (MDV) vaccines of serotypes 1 and 2 administered in 18-day-old embryonated eggs induced better protection against post-hatch challenge at 3 days with virulent MDV than vaccines given at hatch. Embryonal vaccination with a polyvalent vaccine containing equal quantities of serotypes 1 and 2 of MDV and serotype 3 virus (turkey herpesvirus, HVT) was also significantly more effective than post-hatch vaccination. These and earlier results indicate that protective efficacy of single or combined Marek's disease vaccine serotypes against post-hatch challenge at 3 days can be substantially improved if the vaccines are injected into 18-day embryos rather than at hatch. Injection of vaccines of serotypes 1 or 2 into embryonated eggs or hatched chicks did not cause detectable gross or microscopic lesions in chickens. Vaccine viruses of serotypes 1 and 2 could be isolated from spleen cells of chickens 1 week post-vaccination, and the titer of recoverable viruses was higher in chickens that received the vaccines at the 18th day of embryonation than in chickens vaccinated at hatch. Although embryo vaccination with HVT usually provided better protection than post-hatch vaccination against early post-hatch challenge with variant pathotypes of MDV, the protection was poor regardless of vaccination protocol. If challenge with variant pathotypes of MDV was delayed until embryonally or post-hatch HVT-vaccinated chickens were 21 days of age, protection of chickens by HVT was not enhanced. Thus, resistance induced by embryonal vaccination with HVT was qualitatively similar to that induced by post-hatch vaccination with this virus.  相似文献   

15.
Foot-and-mouth disease virus (FMDV) causes a highly contagious infection in cloven-hoofed animals. The format of FMD virus-like particles (VLP) as a non-replicating particulate vaccine candidate is a promising alternative to conventional inactivated FMDV vaccines. In this study, we explored a prokaryotic system to express and assemble the FMD VLP and validated the potential of VLP as an FMDV vaccine candidate. VLP composed entirely of FMDV (Asia1/Jiangsu/China/2005) capsid proteins (VP0, VP1 and VP3) were simultaneously produced as SUMO fusion proteins by an improved SUMO fusion protein system in E. coli. Proteolytic removal of the SUMO moiety from the fusion proteins resulted in the assembly of VLP with size and shape resembling the authentic FMDV. Immunization of guinea pigs, swine and cattle with FMD VLP by intramuscular inoculation stimulated the FMDV-specific antibody response, neutralizing antibody response, T-cell proliferation response and secretion of cytokine IFN-γ. In addition, immunization with one dose of the VLP resulted in complete protection of these animals from homologous FMDV challenge. The 50% protection dose (PD50) of FMD VLP in cattle is up to 6.34. These results suggest that FMD VLP expressed in E. coli are an effective vaccine in guinea pigs, swine and cattle and support further development of these VLP as a vaccine candidate for protection against FMDV.  相似文献   

16.
In the course of vaccine controls, the potency of 25 foot-and-mouth disease (FMD) vaccines was tested quantitatively in parallel in cattle using the intradermal infection and the determination of the SN titres. More than 95% of the vaccinated cattle with SN titres of greater than 1:20 were protected from generalized FMD, regardless of the virus type tested. 61.5% of the vaccinated cattle with SN titres less than or equal to 1:20 were not protected and developed generalized FMD. Comparison of the PD50 values calculated from the results of the intradermal infection and the corresponding SN titres (minimum protection titre greater than 1:20) showed that the results were in complete agreement in 56% of the tested vaccines. In a further 32% of vaccines, the PD50 calculated from the SN titre was slightly below that for the intradermal infection, in the remaining 12% it was somewhat above. The possibility of using the minimum titre determination for testing a vaccine and the significance of this titre as an expression of protection by vaccination are discussed.  相似文献   

17.
口蹄疫是一种感染牛、羊和猪等偶蹄动物、具有高度传染性的动物疫病。疫苗免疫是控制该病的关键措施之一,口蹄疫灭活疫苗在口蹄疫流行地区广泛使用。灭活疫苗中,完整口蹄疫病毒粒子(146S粒子)是至关重要的免疫抗原,它的数量和稳定性决定了疫苗的免疫效果。不同血清型,甚至同型不同毒株的口蹄疫病毒粒子稳定性不同,146S粒子在一定温度、酸、碱条件下容易分解为五聚体(12S粒子),导致疫苗免疫效力大幅下降。近年来口蹄疫病毒结构及其稳定性的分子基础研究取得了一定进展,为研究口蹄疫病毒稳定性提高疫苗质量,开发新型口蹄疫空衣壳疫苗提供了重要的理论基础。本文简要介绍了口蹄疫病毒结构基础、稳定性研究方法和研究进展。为同行了解口蹄疫病毒结构与免疫的关系,评价新型疫苗提供一些参考信息。  相似文献   

18.
Following an outbreak of FMD caused by an A5 strain in the spring of 1984, ten cattle were vaccinated with samples of the five commercial vaccines used for the vaccination campaign in that year, i.e. two animals per vaccine. Six weeks later the cattle were challenged by contact with animals inoculated with the virus strain isolated from the field outbreak. Seven of the ten cattle became severely ill, exhibiting the typical symptoms of FMD, one animal did not show any clinical symptoms, the remaining two weak ones that might have escaped recognition by the cattlemen. Virus could be recovered from the vaccinated animals from days 2 to 10 following contact with the non-vaccinated infected cattle. It was concluded that a single vaccination does not protect cattle against the isolate.  相似文献   

19.
Foot and mouth disease (FMD) outbreaks usually have devastating effects on the economy of countries were disease is endemic due to direct and indirect cost; most of them related to international trade embargoes of animals and animal products. Although currently used inactivated vaccine provides protection, it has several drawbacks like short duration of immunity, and the requirement for containment facilities. A DNA vaccine construct which expresses the secretary antigens, delivered through micro particles could be one of the alternate approaches to overcome these limitations. Present study is envisaged to prepare a DNA vaccine construct containing the VP1 sequence of FMDV serotype O in pVAC vector. DNA vaccine was formulated by adsorbing plasmid DNA construct on cationic micro particles and administered in guinea pigs @25 μg DNA vaccine construct per animal intramuscularly. Sera samples collected were analyzed by sandwich ELISA and SNT, shown enhanced immune response in PLG adjuvanted DNA vaccine. MTT and 3H Thymidine incorporation have shown good CMI responses to PLG adjuvanted DNA. When challenged with 100 gpid50 of homologous virus 5 of the six animals were protected.  相似文献   

20.
The antibody response of cattle after vaccination against foot-and-mouth disease (FMD) virus was monitored using the serum neutralization test (SNT), the sandwich ELISA, liquid-phase ELISA, sandwich competition ELISA, liquid-phase competition ELISA, and the liquid-phase sandwich competition (blocking) ELISA. The competition ELISAs (in particular the "blocking" ELISA) were the most effective at detecting reactivity in these cattle sera. However, 95% of negative sera also competed in the most sensitive ELISA (the "blocking" ELISA) to titres of 1:32 (4% of the sera competed to a titre of 1:128). Comparisons between the different ELISAs, and between these ELISAs and the SNT, demonstrated that the tests were not measuring exactly the same reaction of antibody with FMD virus. With respect to the capacity of animals to resist FMD virus challenge, neither the SNT nor the competition ELISAs were consistently able to identify such animals. The anti-FMD virus antibody titres obtained could be classified into three zones; the "white zone" wherein antibody titres were high and donor animals likely to be protected; the "black zone" wherein antibody titres were low and donor animals likely to be susceptible to infection; the "grey zone" wherein the antibody titres were intermediary and no interpretation could be made with respect to protection. Assays such as ELISA and SNT cannot and do not measure immunological protection; they are a measure of antibody responses and nothing more, and should be interpreted in terms of the "three zone" phenomenon.  相似文献   

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