A single vaccine for the control of capripox infection in sheep and goats

A single vaccine against capripox was developed to protect sheep and goats throughout the capripox enzootic area. The vaccine was stable and safe to use, and provided substantial protection against capripox for at least a year. Preliminary field trials in the Middle East indicated that the vaccine was effective in controlling capripox in indigenous breeds of sheep and goats.     

Vaccination of sheep with cell culture grown orf virus

Orf virus, derived from contagious pustular dermatitis (scabby mouth) lesions in sheep, was adapted to cell culture and subsequently evaluated as a potential vaccine for sheep. The traditional vaccine virus, prepared from the infected scabs of orf virus lesions in sheep, was used to vaccinate sheep by scratching with an applicator (mounted pins) dipped in virus. Less than 10 TCID50 (50% tissue culture infectious doses) of virus was required to produce large lesions (greater than 5 mm diameter) which developed during a period of 10 to 14 d prior to onset of healing which was complete by 28 to 30 d. A serum neutralising antibody response was also detected and protection against challenge by application of virulent virus to abraded skin was demonstrated in that challenge lesions developed and healed more quickly (14 d against 30 d). However, cell culture-adapted virus required more than 10(5) TCID50 to induce even small lesions (less than 2 mm diameter). An antibody response could not be detected and no evidence of protection against challenge with virulent virus was demonstrated. In contrast, a recent field isolate has yielded a cell culture-adapted virus preparation that readily infects sheep, produces large lesions, detectable antibody and protects against challenge. This isolate is distinct from the traditional vaccine strain on the basis of restriction enzyme analysis but provides cross-protection in sheep inmmunisation and challenge studies. These results demonstrate that a cell culture produced scabby mouth vaccine is feasible.     

Evaluation of vaccines against ovine dermatophilosis

Intradermal vaccination of live crude filaments (vaccine A) was compared with a vaccine (vaccine B) consisting of a 45 kD zoospore protein and mucoid material coating filaments in its ability to protect sheep from experimental Dermatophilus congolensis infection. Fourteen and 21 days after challenge, vaccine A sheep had fewer lesions (P less than 0.001) than the vaccine B sheep. The lesions on the vaccine A sheep were also less severe 14 and 21 days after challenge (P less than 0.05, P less than 0.01 respectively). In a second study, vaccine A was assessed for its ability to protect against natural challenge. Ten weeks after contact with sheep with active and generalised dermatophilosis no difference was found between the number of lesions present on the vaccine A and unvaccinated sheep and no differences were found in the number of sheep in each group with active lesions.     

日本血吸虫病核酸疫苗的研究

核酸疫苗能同时诱发体液免疫和细胞免疫 ,具有众多传统疫苗无法比拟的优点 ,并且佐剂的应用能增强核酸疫苗的免疫效果。抗日本血吸虫核酸疫苗的研究在实验动物和牛、羊等大家畜上取得一定进展 ,混和或多价疫苗是未来核酸疫苗的发展方向     

羊口蹄疫免疫方法及效果研究

通过对陕西省绥德县15乡镇15户养羊户饲养的未免疫4~7月龄羊150只,分别进行口蹄疫灭活疫苗一次免疫（150只）、加强免疫（其中30只）,并开展抗体检测,结果发现一次免疫抗体合格率为55.33%,加强免疫合格率为93.33%。试验表明,加强免疫后羊免疫抗体合格率可以得到保证,并根据免疫试验进行分析,为今后羊口蹄疫科学免疫提出合理的建议。     

Laboratory evaluation of a living attenuated vaccine against bluetongue type 20 virus

Living attenuated bluetongue Type 20 virus vaccine was tested in 9 to 12 month-old Australian Merino sheep, held in air conditioned, insect-free accommodation. The vaccine appeared avirulent and immunogenic and protected against infection with a second dose of homologous vaccine virus. No enhancement of virulence or significant change in immunogenicity was observed when the vaccine was passaged 3 times through sheep without antibody to bluetongue virus.     

Induction of immune responses in sheep by vaccination with liposome-entrapped DNA complexes encoding Toxoplasma gondii MIC3 gene

Toxoplasma gondii is a parasite that has been extensively studied due to its medical and veterinary importance in terminating pregnancies. Consequently, a satisfactory vaccine is required to control its adverse effects on pregnant animals. The microneme protein, MIC3, is a major adhesion protein that binds to the surface of host cells and parasites, and is therefore a potential vaccine against T. gondii. The viability of MIC3 as a vaccine is investigated in this study. Sheep were injected twice, intramuscularly, with plasmids containing DNA encoding for the mature form of MIC3 protein formulated into liposomes. Control sheep were injected with an empty vector or received no injections. The injection of sheep with DNA plasmids encoding for MIC3 elicited an immune response after the first and second injections as indicated by antibody responses and the production of IFN-gamma. The immune response, as measured by the IgG2 and IgG1 serum levels, was boosted after the injection of the MIC3 DNA vaccine together with high anti-MIC3 antibodies. The results demonstrate that the intramuscular injection of sheep with a plasmid containing DNA coding for MIC3 protein induces a significant and effective immune response against T. gondii.     

Evidence for the transmission of scrapie to sheep and goats from a vaccine against Mycoplasma agalactiae

An accidental infection from a vaccine was suggested as the explanation for the sudden increase in outbreaks of scrapie in Italy in 1997 and 1998. This paper describes a recent outbreak of scrapie in sheep and goats which were exposed to the same vaccine. No ewes or goats had been imported into the herd since 1992, but a vaccine against Mycoplasma agalactiae had been administered twice, in 1995 and 1997. High rates of crude mortality and scrapie incidence were experienced by both species, all birth cohorts were involved and a large proportion of aged animals was affected. A pattern of brain lesions was observed, with slight differences between the sheep and goats, which was very similar to the pattern observed in animals previously exposed to the same vaccine but clearly different from that observed in the brains of sheep with scrapie in a flock not exposed to the vaccine. Regardless of their exposure status, genotype analysis of the sheep showed the presence of polymorphism only at codon 171. The patterns of both incidence and brain lesions provide evidence that the epidemic of scrapie was due to the use of the vaccine.     

Detection of wild-type Aujeszky's disease virus by polymerase chain reaction in sheep vaccinated with a modified live vaccine strain

An outbreak of Aujeszky's disease occurred in a flock of sheep which had been housed together with pigs. After the death of five sheep with clinical signs of Aujeszky's disease, the remaining sheep were vaccinated with the Bartha vaccine strain, and the pigs were vaccinated with the 783 vaccine strain of Aujeszky's disease virus. Despite vaccination, however, more sheep died. Brain tissues from four sheep were collected for virus isolation and for immunobistological examinations. Only vaccine virus (gE-negative) was detected in the tissue. After DNA restriction enzyme analysis of the isolated virus, DNA of one or both of the vaccine strains was detected in all sheep. In one sheep field virus DNA was also detected. However, when the polymerase chain reaction was performed on samples prepared from paraffin-embedded tissues, DNA of field virus (gE-positive) was detected in all four sheep. It was probable that the sheep had not yet mounted a sufficient immune response to the vaccine virus, or were already infected with field virus at the time of vaccination. We concluded that the sheep died from field virus infection and not from vaccine virus infection and that only the polymerase chain reaction made it possible to specifically detect even very small amounts of field virus DNA among vaccine virus DNA in all investigated sheep.     

Comparison of alum-absorbed or non-alum-absorbed oil emulsion vaccines containing either pilate or non-pilate Bacteroides nodosus cells in inducing and maintaining resistance of sheep to experimental foot rot

Highly pilate (P) or non-pilate (NP) cells of Bacteroides nodosus were compounded into oil emulsion (O) either with or without prior absorption onto alum (A). The abilities of these four preparations (referred to as PAO, NPAO, PO and NPO vaccines) to stimulate antibody production and to protect sheep from foot rot were compared. Two injections of PAO vaccine protected sheep against homologous challenge 12 weeks after the second dose by PO, NPO and NPAO vaccines were less effective. Sheep were protected against homologous challenge for 14 weeks after a single dose of PAO vaccine and for 22 weeks after three doses; an ameliorative effect was still evident 40 weeks after the third dose. Protection against challenge with two heterologous strains was demonstrated at six weeks after three doses of vaccine. A numerical system of scoring the lesions also confirmed that foot rot in vaccinated sheep challenged outside the 'protective' period of the vaccine was somewhat less severe than in controls. PAO vaccine induced much higher and more persistent titres of agglutinins than the other vaccines tested. There was a relationship between agglutinin titres and resistance to homologous challenge.     

Vaccines against bluetongue in Europe

After the incursion of bluetongue virus (BTV) into European Mediterranean countries in 1998, vaccination was used in an effort to minimize direct economic losses to animal production, reduce virus circulation and allow safe movements of animals from endemic areas. Vaccination strategies in different countries were developed according to their individual policies, the geographic distribution of the incurring serotypes of BTV and the availability of appropriate vaccines. Four monovalent modified live virus (MLV) vaccines were imported from South Africa and subsequently used extensively in both cattle and sheep. MLVs were found to be immunogenic and capable of generating strong protective immunity in vaccinated ruminants. Adverse side effects were principally evident in sheep. Specifically, some vaccinated sheep developed signs of clinical bluetongue with fever, facial oedema and lameness. Lactating sheep that developed fever also had reduced milk production. More severe clinical signs occurred in large numbers of sheep that were vaccinated with vaccine combinations containing the BTV-16 MLV, and the use of the monovalent BTV-16 MLV was discontinued as a consequence. Abortion occurred in <0.5% of vaccinated animals. The length of viraemia in sheep and cattle that received MLVs did not exceed 35 days, with the single notable exception of a cow vaccinated with a multivalent BTV-2, -4, -9 and -16 vaccine in which viraemia persisted at least 78 days. Viraemia of sufficient titre to infect Culicoides insects was observed transiently in MLV-vaccinated ruminants, and natural transmission of MLV strains has been confirmed. An inactivated vaccine was first developed against BTV-2 and used in the field. An inactivated vaccine against BTV-4 as well as a bivalent vaccine against serotypes 2 and 4 were subsequently developed and used in Corsica, Spain, Portugal and Italy. These inactivated vaccines were generally safe although on few occasions reactions occurred at the site of inoculation. Two doses of these BTV inactivated vaccines provided complete, long-lasting immunity against both clinical signs and viraemia, whereas a single immunization with the BTV-4 inactivated vaccine gave only partial reduction of viraemia in vaccinated cattle when challenged with the homologous BTV serotype. Additional BTV inactivated vaccines are currently under development, as well as new generation vaccines including recombinant vaccines.     

Reduction in mortality from heartwater in cattle, sheep and goats exposed to field challenge using an inactivated vaccine

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).     

A field trial to assess the therapeutic and prophylactic effect of a foot rot vaccine in sheep

An 18-week field trial was conducted on a sheep ranch to evaluate the therapeutic and prophylactic effect of a commercial foot rot vaccine. Two hundred sheep were included in the study, 100 with detectable foot rot lesions and 100 without. Approximately 50 sheep from each group were selected randomly and vaccinated twice against foot rot at a 6-week interval in the late spring 1984; the remaining sheep acted as nonvaccinated controls. Therapeutic effect of the vaccine was demonstrated by a cure rate of 53% in vaccinated, foot rot-affected sheep vs a cure rate of 19% in nonvaccinated, foot rot-affected sheep. Prophylactic effect of the vaccine was demonstrated by a foot rot prevalence at the end of the 18-week period of 9% for vaccinated sheep vs 53% for nonvaccinated sheep. Associations of foot rot lesions and vaccination with body condition were found to be significant, as was the association between foot rot lesions and mortality.     

Attenuation of a strain of rinderpest virus: potential homologous live vaccine

Peste des petits ruminants (PPR) is a highly contagious disease of small ruminants frequently associated with severe mortality in these hosts. In countries where it occurs, PPR represents an important constraint to the improved productivity of sheep and goats. Until now the only way to combat this plague has been the use of heterologous rinderpest vaccine; all attempts to develop a homologous vaccine have ended in failure. The present communication describes the attenuation of the Nigerian strain PPRV Nig 75/1 by serial passage in Vero cells. The avirulent virus obtained has the same characteristics as Plowright and Ferris' rinderpest vaccine. The virus is advanced as a potential homologous vaccine against PPR.     

小反刍兽疫活疫苗的安全性评价试验

2007年小反刍兽疫(PPR)在我国西藏首次暴发,在西藏和新疆部分地区使用PPR Nigeria 75/1疫苗株制造的疫苗进行免疫接种。为明确疫苗的安全性,中国兽医药品监察所国家牛瘟参考实验室对其安全性能进行了系统评价。健康易感山羊、绵羊及怀孕山羊、怀孕绵羊按不同剂量接种疫苗后,均未观察到异常临床反应;怀孕母羊所产羔羊数量与对照组无明显差异。疫苗对小白鼠、豚鼠的非特异性安全试验表明,所有接种动物均健活。结果表明该疫苗安全性良好,可在田间大规模使用。     

An improved Corynebacterium pseudotuberculosis vaccine for sheep

Extensive experiments in mice confirmed that the immunogenicity of a Corynebacterium pseudotuberculosis vaccine could not be significantly improved with the use of various adjuvants. Immunity against C. pseudotuberculosis likewise could not be enhanced by incorporating various immunostimulants into the vaccine or by the use of live vaccines. However, a combination of aluminium hydroxide gel and saponin as adjuvant did have a beneficial effect. This vaccine was tolerated better, and a smaller dose apparently protected sheep more effectively against intralymph node challenge than the currently available alum-precipitated vaccine.     

Immunisation against infections caused by Listeria monocytogenes in sheep

Immunisation against listeriosis in sheep using a live, attenuated vaccine was introduced in Norway in 1984. Since then 65,000 to 80,000 animals have been vaccinated annually. Information obtained by a questionnaire showed that the incidence of listeriosis decreased from approximately 4.0 per cent before the introduction of the vaccine to 1.5 per cent after vaccination started. The incidence of abortions was 0.7 per cent in vaccinated flocks compared to 1.1 per cent in unvaccinated flocks. There were a few adverse reactions in the vaccinated sheep.     

Impact of footrot vaccination and antibiotic therapy on footrot and contagious ovine digital dermatitis

Footrot and contagious ovine digital dermatitis (CODD) are common causes of foot disease of sheep in the UK. The study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a UK sheep farm affected by CODD and footrot. The sheep were randomly assigned to one of two treatment protocols. In protocol A, all sheep were given two doses of footrot vaccine (Footvax, MSD), plus targeted antibiotic therapy (long-acting amoxicillin, Betamox LA, Norbrook Pharmaceuticals) to sheep with foot lesions likely to be associated with a bacterial infection. In protocol B, the sheep only received targeted antibiotic therapy. Sheep were re-examined and foot lesions recorded five and nine weeks later. New infection rates in the footrot vaccinated group were lower compared with the vaccinated group for both CODD (18.2 per cent compared with 26.4 per cent, P=0.014) and footrot (12.55 per cent compared with 27.5 per cent, P<0.001). Recovery rates were unaffected for CODD (80.46 per cent compared with 70.97 per cent, P=0.14) but higher for footrot (92.09 per cent compared with 81.54 per cent, P=0.005) in sheep which received the vaccine. On this farm, a footrot vaccine efficacy of 62 per cent was identified against footrot and 32 per cent against CODD infection. An association between a sheep having footrot at visit 1 and subsequently acquiring CODD was identified (odds ratio [OR] 3.83, 95 per cent CI 2.61 to 5.62, P<0.001). These results suggest a role for infection with Dichelobacter nodosus in the aetiopathogenesis of CODD on this farm.     

Vaccination of sheep against Aujeszky's disease with a gI-deleted mutant]

The use of gl deleted live vaccines against Aujeszky's disease (AD) facilitates to differentiate vaccinated from field-virus infected animals. In this study different modes of vaccination were tried to find out how sheep can be protected from a lethal infection with ADV. It could clearly be demonstrated that Aujeszky disease virus (ADV) is spread by horizontal transmission from infected pigs to sheep. The nasal discharges of infected pigs contained a maximum of 10(8.75)TCID50/g mucus at days 3 and 4 p.i. and those of the contact-pigs 10(8.5)TCID50/g mucus at days 6 and 7 after contact. Non-vaccinated contact sheep were infected horizontally by the pigs. The highest titres ranged from 10(6.25) to 10(7.5)TCID50/g mucus. These animals were sacrificed at day 5 p.i. exhibiting acute symptoms of AD. The nasal discharge of vaccinated sheep contained much lower amounts of ADV (maximum: 10(4.25)TCID50/g mucus). All surviving animals had developed antibodies. Following challenge with the ADV-strain NIA3, no febrile response or virus-shedding was observed in sheep vaccinated 2x s.c. or 2x i.m. with a gl deleted live vaccine, whereas sheep, vaccinated only 1x i.m. (4 out of 4 animals) or 1x i.m. (3 out of 4 animals) or 1x i.n. and 1x i.m. (1 out of 4 animals) had to be sacrificed after showing acute symptoms of AD. In conclusion it can be stated that a double parental vaccination with a gl deleted live vaccine protects sheep against a field-virus AD infection.