Vaccination Of Goats Research Articles

Safety and immunogenicity of Onderstepoort Biological Products' Rift Valley fever Clone 13 vaccine in sheep and goats under field conditions in Senegal.

This blinded field safety study was conducted in Senegal to assess safety and immunogenicity of administration of the registered dose of Rift Valley fever virus (RVFV) Clone 13 vaccine (Onderstepoort Biological Products) to sheep and goats of West African breeds under natural conditions. A total of 267 small ruminants (220 sheep, 47 goats) were included; half received RVFV Clone 13 vaccine at the recommended dose and half received the diluent (as placebo) only. The study was performed on three commercial farms in the northern and eastern region of Senegal in accordance with veterinary good clinical practices. The animals were observed daily for 3 days after vaccination, and then weekly for 1 year. In both sheep and goats vaccinated against RVFV seroconversion rates above 70% were recorded. No seroconversion related to RVFV was observed in placebo-treated animals. No statistically significant differences were determined between placebo and vaccinated groups for mean rectal temperatures for the first 3 days after administration (p > 0.05). No abnormal clinical signs related to treatment were noted, and only one slight injection site reaction was observed in one vaccinated animal for 2 days after vaccination. Out of 176 births assessed over 1 year (93 from the vaccinated group, 83 from the placebo group), 9 were abnormal in the placebo group and 3 in the vaccinated group (p > 0.05). The frequency of adverse events was similar in the placebo and vaccinated groups. RVFV Clone 13 vaccine administered according to the manufacturer's instructions was safe and well tolerated in West African breeds of sheep and goats, including animals of approximately 6 months of age and pregnant females, under field conditions in Senegal. Antibody levels persisted up to 1 year after vaccination.

Vaccination of kids under one month of age with a killed vaccine and reduction in the frequency of faecal shedding of Mycobacterium avium subspecies paratuberculosis

A study was conducted under field conditions in two French dairy goat herds in order to evaluate the efficacy of a killed MAP vaccine in goats vaccinated before one month of age, by measuring production, epidemiological and pathogenetic effects. In each herd, half of the replacement kids were vaccinated, the other half were used as controls. Samples of blood/sera and faeces were collected from each goat at intervals of approximately every seven months for 31 months, to evaluate immune responses and faecal shedding. Goats culled during the study were submitted to ‘post-mortem’ examinations (gross lesions, culture on tissues and ZN staining). The milk production of each goat was recorded for the first four years of lactation. Compared to controls, the average annual milk production levels of vaccinates was significantly higher. Vaccination was associated with a reduction in the frequency of faecal shedding. The percentages of shedding goats detected by faecal culture dropped significantly to 0% versus 4% at 15.5 months PV, 3% versus 16% at 23 months PV and 8% versus 20% at 30.5 months PV, in vaccinates and in controls, respectively. The stimulation of both the cell-mediated and humoral immune systems by vaccination was evident from the elevated proportion of positive reactors for both tests in vaccinates compared to controls. To conclude, this study confirmed the results previously obtained in goats on the efficacy of a killed vaccine in controlling paratuberculosis by reducing faecal shedding of MAP.

English

This study was conducted between September 2012 and May 2013 in three Districts of Borana pastoral area to determine seroprevalence of contagious caprine pleuropneumonia (CCPP) and assess field performance of inactivated commercial vaccine, produced by the National Veterinary Institute (NVI) in Ethiopia, against CCPP. Both pre and post vaccination sera samples were tested using competitive enzyme linked immunosorbent assay (cELISA). Out of 510 examined sera, 161 samples were positive for CCPP, giving an overall seroprevalence of 31.6% (95% CI = 27.57-35.64%) in the study area. Seroprevalence of 35.2, 35.1 and 25% were recorded in Arero, Dhas and Yabello districts, respectively. However, there was no significant difference (χ2=5.56, P=0.062) in seropositivity among the three districts and between male and female goats (χ2=0.068, P=0.794) examined in this study. On the other hand, the differences in seroprevalence among the age categories were statistically significant (χ2=24.48, p<0.0001). A rise in antibody (seroconversion) was observed after field vaccination of goats with inactivated CCPP vaccine and a total of 253 of the 414 examined sera samples were positive for Mycoplasma capricolum subsp. capripneumoniae (Mccp) specific antibodies, thus 61.1% of goats seroconverted following vaccination. Comparison of Mccp specific antibodies in the goat population before and after vaccination indicated that the number of positive reactors increased significantly (P<0.0001) following CCPP vaccination. Seropositivity following vaccination was analyzed among the three age groups and statistically significant differences (χ2=45.48, P<0.0001) were recorded. The change in the serum antibody after vaccination was found to be higher in younger and adult aged goats than old aged goats. In conclusion, the present study indicates that CCPP is one of the major goat health problems in Borana pastoral area which warrants appropriate measures to be in place towards the prevention and control of the disease. Moreover, field vaccination of goats by inactivated CCPP vaccine induced seropositivity in majority of the inoculated goats. Future controlled experimental studies with challenge infection after vaccination need to be conducted for further evaluation of the vaccine efficacy. Key words: Borana pastoral area, contagious caprine pleuropneumonia (CCPP), goats, inactivated vaccine, seroconversion,  seroprevalence.

Protective immune response of live attenuated thermo-adapted peste des petits ruminants vaccine in goats.

Virulent isolate of peste des petits ruminants virus (PPRV) of Indian origin (PPRV Jhansi 2003) initially adapted in Vero cells was further propagated in thermo-adapted (Ta) Vero cells grown at 40°C for attaining thermo-adaption and attenuation of virus for development of Ta vaccine against PPR in goats and sheep. The virus was attenuated up to 50 passages in Ta Vero cells, at which, the virus was found sterile, innocuous in mice and guinea pigs and safe in seronegative goats and sheep. The developed vaccine was tested for its immunogenicity in goats and sheep by subcutaneous inoculation of 100 TCID50 (0.1field dose), 10(3) TCID50 (one field dose) and 10(5) TCID50 (100 field doses) of the attenuated virus along with controls as per OIE described protocols for PPR vaccine testing and were assessed for PPRV-specific antibodies 7-28days post vaccination (dpv) by PPR competitive ELISA and serum neutralization tests. The PPRV antibodies were detected in all immunized goats and sheep and goats were protective when challenged with virulent PPRV at 28th dpv along with controls for potency testing of the vaccine. The attenuated vaccine did not induce any adverse reaction at high dose (10(5) TCID50) in goats and sheep and provided complete protection even at low dose (10(2) TCID50) in goats when challenged with virulent virus. There was no shedding and horizontal transmission of the attenuated virus to in-contact controls. The results indicate that the developed PPR Ta attenuated virus is innocuous, safe, immunogenic and potent or efficacious vaccine candidate alternative to the existing vaccines for the protection of goats and sheep against PPR in the tropical countries like India.

Immunization with H7-HCP-Tir-Intimin Significantly Reduces Colonization and Shedding of Escherichia coli O157:H7 in Goats

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is the causative agent of hemorrhagic colitis and hemolytic uremic syndrome in humans. However, the bacterium can colonize the intestines of ruminants without causing clinical signs. EHEC O157:H7 needs flagella (H7) and hemorrhagic coli pili (HCP) to adhere to epithelial cells. Then the bacterium uses the translocated intimin receptor (Tir) and an outer membrane adhesion (Intimin) protein to colonize hosts. This leads to the attachment and effacement of (A/E) lesions. A tetravalent recombinant vaccine (H7-HCP-Tir-Intimin) composed of immunologically important portions of H7, HCP, Tir and Intimin proteins was constructed and its efficacy was evaluated using a caprine model. The results showed that the recombinant vaccine induced strong humoral and mucosal immune responses and protected the subjects from live challenges with EHEC O157:H7 86-24 stain. After a second immunization, the average IgG titer peaked at 7.2×105. Five days after challenge, E. coli O157:H7 was no longer detectable in the feces of vaccinated goats, but naïve goats shed the bacterium throughout the course of the challenge. Cultures of intestinal tissues showed that vaccination of goats with H7-HCP-Tir-Intimin reduced the amount of intestinal colonization by EHEC O157:H7 effectively. Recombinant H7-HCP-Tir-Intimin protein is an excellent vaccine candidate. Data from the present study warrant further efficacy studies aimed at reducing EHEC O157:H7 load on farms and the contamination of carcasses by this zoonotic pathogen.

Peste des Petits Ruminants Vaccine (Nigerian Strain 75/1) Confers Protection for at Least 3 Years in Sheep and Goats

The present study reports the duration of immunity and protective efficacy of Peste des Petits Ruminants (PPR) vaccine (Nigerian strain 75/1) in sheep and goats. A total of 105 sheep and goats were divided into three groups A, B and C. Group A received normal recommended dose (1.0 ml) of PPR vaccine, group B received half dose (0.5 ml) of PPR vaccine and group C was kept as unvaccinated control group in contact with vaccinated animals. The post vaccination dynamics of antibodies against PPR virus was studied. It was found that significant antibody titres persisted for 3 years post vaccination in sheep and goats vaccinated with either full dose or half dose of PPR vaccine. The challenge protection studies were carried out in experimental animals at 24 and 36 month post vaccination. The vaccinates withstood challenge and were found completely resistant clinically and virologically to virulent PPR virus for 24 and 36 months post vaccination. The unvaccinated control animals developed typical clinical signs of PPR and the challenged virus was detected in ocular, nasal and oral secretions of these animals. This study demonstrated that a single immunization with PPR vaccine conferred solid protection in sheep and goats for 3 years.

22 Study the Immune Response of Conjunctival and Subcutaneous Vaccination of Goats with RB51 Vaccine for Controlling Brucellosis

This study was conducted to evaluate the efficacy of RB51 vaccine in immunization of goats against brucellosis although it is a specific vaccine for cattle, fifteen pregnant and non-pregnant goats were divided into three groups, 5 goats were injected subcutaneously(S/C) with 2 mls of RB51 vaccine which contain 4 × 108 CFU , 5 goats were vaccinated through conjunctival route (C/J) with 0.2 ml of RB51 which contain 4 × 108 CFU , and the last 5 goats were injected with PBS and kept as control group. It has been ascertained that no abortion occurred in the vaccinated animals except one case of a weak kid was born in S/C vaccinated group. Humeral immune response for the vaccinated animals measured by serological test (Rose Bengal and Passive hemagglutination tests) every two weeks, while the cellular immune response measured by brucellin test at the 6th week. Passive haemaglutination test (PHA) was positive and the antibodies were increased significantly (P<0.05) at the 2nd week to reach 10.4±2.4 and 6.4±0.9 in S/C and C/J routes respectively, and increased significantly (P<0.05) at 8th week to reach 38.4±6.4 and 22.4±3.9 in S/C and C/J routes respectively, and decreased significantly at 12th week which reach 9.6±1.6 to 6.4±0.9. Brucellin from RB51 strain prepared to be used as antigen in the PHA test and also in skin test to determine delayed type hypersensitivity, serial dilutions of RB51 brucellin had been done to confer the optimal concentration in skin test that did not induce toxicity for mice 40µg was the optimal concentration that has been given to goats. In goats the results indicated that the S/C group showed a high delayed type hypersensitivity compared with C/J group and the good skin reactions was increased to reach the maximum at 48 hrs post brucellin injection (PBI), when the erythema diameter reached 7.1±0.09mm and 5.4±0.3mm in S/C and C/J groups respectively and skin thickness was2.9±0.1 mm and 2.1±0.2 mm in S/C and C/J groups respectively. These results showed that immunized animals expressed cellular and humeral immune response examined by DTH and PHA. Concluded that the RB51 vaccine gave good level of immunization in goats and it can be considered as alternative vaccine against heterogonous Brucella spp.

Vaccination of goats with DNA vaccine encoding Dim-1 induced partial protection against Haemonchus contortus: A preliminary experimental study

Disorganized muscle family member (Dim-1) belongs to immunoglobulin superfamily, and is a structural protein localized to the region of the muscle cell membrane around and between the dense bodies. Strong immunogenicity to host’s immune system was induced by Dim-1 from Ascaris suum, which indicated that Dim-1 could be a potential candidate for vaccine. The homologues of Dim-1 were also detected in nematodes Brugia malayi and Trichostrongylus colubriformis. However, information on the complete coding sequence and protection potential of this molecule in Haemonchus contortus is lacking. In this study, full length of Dim-1 cDNA was cloned using a rapid amplification of cDNA ends (RACE) strategy and the DNA vaccine encoding Dim-1 open reading frame (ORF) was tested for protection against experimental H. contortus infections in goats. Fifteen goats were allocated into three trial groups. The animals of Dim-1 group were vaccinated with the DNA vaccine encoding Dim-1 on day 0 and 14, and challenged with 5000 infective H. contortus third larval stage (L3) on day 28. An unvaccinated positive control group was challenged with L3 at the same time. An unvaccinated negative control group was not challenged with L3. The results indicated Dim-1 DNA vaccines were transcribed at local injection sites and expressed in vivo post immunizations respectively. Following L3 challenge, the mean eggs per gram feces (EPG) and worm burdens of Dim-1 group were reduced by 45.7% and 51.1%, respectively. Significantly high levels of serum IgG, serum IgA, mucosal IgA, CD4+ T lymphocytes and B lymphocytes of Dim-1 group were produced. While compared with the negative control group, increased numbers of blood eosinophils and lymphocytes and declined haemoglobin level were observed in the Dim-1 group after L3 challenge. The preliminary study suggest that recombinant H. contortus Dim-1 DNA vaccine induced partial immune response and has protective potential against goat haemonchosis.

Study on major causes of kid mortality in Adami Tulu Jido Kombolcha District of Oromia, Ethiopia

A cross sectional investigation was conducted on the major causes of kids’ mortality in Adami Tulu Jiddo Kombolcha district from May 2009 to June 2010 to determine the mortality rate and to identify the potential causes of kids’ mortality in Arsi- Bale kids. A combination of multistage and purposive sampling techniques was used to select the study areas while simple random sampling was adopted to select experimental goats. The result revealed that from a total of 536 kids born over 12 months period about 22.4% (n=120) kids were died. Internal parasite assessment was conducted to see the infection level of parasites infection both on adult and kids of Arsi- Bale goats. Accordingly fecal sample was directly collected from the rectum of the experimental animal and its result showed that from a total of 39 adults and 158 kids fecal sample collected 59.6% ( n=118) was positive and 40.4% (n=80) was negative. The types of internal parasites mostly observed on goats of the study sites were identified as Strongly (90.5%), Monesia (23.3%), Coccidian (8.6%), Fasciola (1.7%) and Ascaris (0.9%). From the positive fecal samples, 51.5% (n=61) is highly infected, 19.5. %( n=23) moderately infected and 28.8 % (n= 34) had low infestation. Diarrhea, diseases and/or internal parasites were responsible for death of kids. Therefore, systematic control of internal parasites and diseases and periodic vaccination of goats against the identified diseases should be in place to improve productivity of goats for economic return.

Vaccination of goats with glyceraldehyde-3-phosphate dehydrogenase DNA vaccine induced partial protection against Haemonchus contortus

Owing to its critical functions in worm physiology, glyceraldehyde-3-phosphate dehydrogenase in Haemonchus contortus (HcGAPDH) is potential candidates for vaccine to control haemonchosis. In this study, DNA vaccine expressing HcGAPDH antigen was tested for protection against experimental H. contortus infections in goats. Fifteen goats (9–10months of age) were allocated into three trial groups. Group 1 was vaccinated with HcGAPDH DNA vaccine twice on days 0 and 14, and then challenged with 5000 infective H. contortus L3 (third stage larvae) on days 28. Group 2 was an unvaccinated positive control group challenged with H. contortus L3 on days 28. Group 3 was an unvaccinated negative control group that was not challenged with L3. By the method of RT-PCR and Western-blot, transcription and expression of HcGAPDH DNA vaccine were identified at local injection sites post immunizations, respectively. After immunization with the DNA vaccine, significantly high levels of serum IgG, serum IgA, mucosal IgA, CD4+ T lymphocytes and B lymphocytes were generated. Also, increased numbers of blood eosinophils and decreased haemoglobin level after challenge were observed in the vaccinated group. Meanwhile, cumulative mean faecal worm egg counts and worm burdens in vaccinated group were reduced by 34.9% and 37.73%, respectively. In brief, recombinant HcGAPDH DNA vaccine induced partial immune response against H. contortus infection in goats.

Shifting priorities in the aftermath of a Q fever epidemic in 2007 to 2009 in the Netherlands: from acute to chronic infection

From 2007 to 2009, the Netherlands faced large seasonal outbreaks of Q fever, in which infected dairy goat farms were identified as the primary sources. Veterinary measures including vaccination of goats and sheep and culling of pregnant animals on infected farms seem to have brought the Q fever problem under control. However, the epidemic is expected to result in more cases of chronic Q fever among risk groups in the coming years. In the most affected area, in the south of the country, more than 12% of the population now have antibodies against Coxiella burnetii. Questions remain about the follow-up of acute Q fever patients, screening of groups at risk for chronic Q fever, screening of donors of blood and tissue, and human vaccination. There is a considerable ongoing research effort as well as enhanced veterinary and human surveillance.

Evaluation of homologous and heterologous protection induced by a virulent field strain of orf virus and an orf vaccine in goats

To evaluate cross protection provided by administration of contagious ecthyma vaccines against strains of orf virus in goats. 126 Boer-Spanish crossbred goats (3 to 20 days old). 85 goats were vaccinated with a goat-derived contagious ecthyma vaccine. Of these, 41 were challenge exposed with the virus strain for the contagious ecthyma vaccine, 40 were challenge exposed with a more virulent field strain of orf virus, and 4 were lost to predation or died. Another 41 goats were vaccinated with a vaccine produced from a more virulent field strain of orf virus; of these, 18 were challenge exposed with the virus strain of the goat-derived contagious ecthyma vaccine, 18 were challenge exposed with the more virulent field strain of orf virus, and 5 were lost to predation or died. Vaccination with the goat-derived contagious ecthyma vaccine did not significantly reduce the number of goats with lesions or lesion severity caused by challenge exposure with the more virulent field strain of orf virus. Vaccination with the vaccine produced from the more virulent field strain of orf virus significantly reduced the number of goats with lesions attributable to challenge exposure with the virus strain of the goat-derived contagious ecthyma vaccine, but it failed to significantly reduce lesion severity. Vaccination did not result in cross protection for the 2 strains of orf virus. This may have been attributable to antigenic differences and may be a factor in outbreaks of contagious ecthyma in vaccinated goats.

Clinical protection, sub-clinical infection and persistence following vaccination with extinction payloads of O1 Manisa foot-and-mouth disease monovalent vaccine and challenge in goats and comparison with sheep

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 O1 Manisa vaccine (0.45–5μg). Vaccinated and sero-negative unvaccinated sheep (n=6) and goats (n=6) were challenged intradermally into the coronary band with O1 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 0.94μg protected sheep and goats against challenge. Sheep and goats vaccinated with 0.45μg antigen payload were poorly protected against challenge. An antigen payload of 0.94μg 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 0.94μg 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 5days 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.

Effect of an inactivated paratuberculosis vaccine on the intradermal testing of goats for tuberculosis

The effect of an inactivated paratuberculosis vaccine on the diagnosis of tuberculosis (TB) in goats was investigated in a herd with a history of clinical paratuberculosis but which was free of TB. Cohorts of animals in 2006, 2008 and 2009, were vaccinated once at 1 month of age, and 50% of the 2006 cohort served as unvaccinated controls. The goats were aged 8 months, 20 months and 3.5 years old at the time of the survey. All animals were assessed using a single intradermal injection of bovine tuberculin purified protein derivative (PPD) (SID test), or using both bovine and avian PPD (CID test). An interferon (IFN)-γ assay using both bovine and avian PPD was carried out on the 2006 cohort and was interpreted according to three different 'cut-off' points. No unvaccinated (control) animals tested positive to any of the assays, confirming that the herd was TB-free. The SID test had a low specificity in vaccinated animals at 8 and 20 months of age, whereas the CID test demonstrated 100% specificity in animals ≥20 months-old. The specificity of IFN-γ assay was less than maximal for vaccinated animals 3.5 years old as small numbers of false positives were detected, although this depended on the chosen cut-off point. The study findings demonstrate that the use of an inactivated paratuberculosis vaccine in goats <1 month-old in a TB-free herd does not result in false positives to a CID test for TB when performed in animals ≥20 months-old.

Neutralizing activities of caprine antibodies towards conserved regions of the HCV envelope glycoprotein E2

Anti HCV vaccine is not currently available and the present antiviral therapies fail to cure approximately half of the treated HCV patients. This study was designed to assess the immunogenic properties of genetically conserved peptides derived from the C-terminal region of HVR-1 and test their neutralizing activities in a step towards developing therapeutic and/or prophylactic immunogens against HCV infection. Antibodies were generated by vaccination of goats with synthetic peptides derived from HCV E2. Viral neutralizing capacity of the generated anti E2 antibodies was tested using in vitro assays. Goats immunized with E2 synthetic peptides termed p412 [a.a 412-419], p430 [a.a 430-447] and p517 [a.a 517-531] generated high titers of antibody responses 2 to 4.5 fold higher than comparable titers of antibodies to the same epitopes in chronic HCV patients. In post infection experiments of native HCV into cultured Huh7.5 cells anti p412 and anti p 517 were proven to be neutralizing to HCV genotype 4a from patients' sera (87.5% and 75% respectively). On the contrary anti p430 exhibited weak viral neutralization capacity on the same samples (31.25%). Furthermore Ab mixes containing anti p430 exhibited reduced viral neutralization properties. From these experiments one could predict that neutralization by Abs towards different E2-epitopes varies considerably and success in the enrichment of neutralization epitope-specific antibodies may be accompanied by favorable results in combating HCV infection. Also, E2 conserved peptides p517 and p412 represent potential components of a candidate peptide vaccine against HCV infection.

Vaccination of goats with a glutathione peroxidase DNA vaccine induced partial protection against Haemonchus contortus infection

Due to their critical functions in worm physiology, glutathione peroxidases in Haemonchus contortus are potential candidates for vaccine to control haemonchosis. However, information on the protection potential of these molecules is lacking. In this study, recombinant HC29 antigen was tested for protection against experimental H. contortus infections in goats. Fifteen animals were allocated into three trial groups. The animals of HC29 group was vaccinated with a recombinant HC29 DNA vaccine twice at day 0 and day 14, and then challenged with 5000 infective H. contortus L3 (third larval stage) on the 28th day. An unvaccinated positive control group was challenged with L3 at the same time. An unvaccinated negative control group was not challenged with L3. The results indicated HC29 DNA vaccine was transcribed at local injection sites and expressed in vivo post immunizations, respectively. Following L3 challenge, the mean eggs per gram feces and worm burdens of HC29 group were reduced by 36.1% and 35.6% respectively compared to the positive control group. After immunization with the DNA vaccine, significantly high levels of serum IgG, serum IgA, mucosal IgA and CD4+ T lymphocytes were detected. These results suggest that recombinant H. contortus HC29 glutathione peroxidase DNA vaccine induced a partial immune response and has protective potentials against caprine haemonchosis.

Reduction ofCoxiella burnetiiPrevalence by Vaccination of Goats and Sheep, the Netherlands

Recently, the number of human Q fever cases in the Netherlands increased dramatically. In response to this increase, dairy goats and dairy sheep were vaccinated against Coxiella burnetii. All pregnant dairy goats and dairy sheep in herds positive for Q fever were culled. We identified the effect of vaccination on bacterial shedding by small ruminants. On the day of culling, samples of uterine fluid, vaginal mucus, and milk were obtained from 957 pregnant animals in 13 herds. Prevalence and bacterial load were reduced in vaccinated animals compared with unvaccinated animals. These effects were most pronounced in animals during their first pregnancy. Results indicate that vaccination may reduce bacterial load in the environment and human exposure to C. burnetii.

Vaccination of goats with DNA vaccines encoding H11 and IL-2 induces partial protection against Haemonchus contortus infection

DNA vaccines expressing Haemonchus contortus H11 antigen with or without interleukin (IL)-2 were tested for protection against H. contortus infection in goats. Sixteen goats (8-10 months of age) were allocated into four trial groups. On days 0 and 14, group 1 was immunised with a DNA vaccine expressing H11 and IL-2 and group 2 was immunised with a DNA vaccine expressing H11 only. Group 3 was an unvaccinated positive control group challenged with H. contortus third stage larvae (L3). Group 4 was an unvaccinated negative control group that was not challenged with L3. Animals in groups 1-3 were challenged with 5000 infective H. contortus L3 14 days after the second immunisation. Transcription of H11 and IL-2 was demonstrated in muscle by reverse transcriptase-PCR 10 days after primary immunisation and translation of H11 was detected by Western blot analysis 7 days after the second immunisation. Following immunisation with a DNA vaccine expressing H11 and IL-2, high levels of specific serum immunoglobulin (Ig) G, non-specific serum IgA, mucosal IgA, CD4(+) T lymphocytes, CD8(+) T lymphocytes and B lymphocytes were produced. Following challenge with L3, cumulative mean faecal worm egg counts and worm burdens in group 1 were reduced by 56.6% and 46.7%, respectively, while corresponding reductions in group 2 were 44.8% and 38.0%. There was a small but significant difference in abomasal worm burdens in goats in groups 1 (395.3±37.6) and 2 (459.5±101.6) compared to group 3 (741.5±241.5; P<0.05). Use of a DNA vaccine expressing H11 and IL-2 conferred partial protection against Haemonchus contortus infection in goats.

Evaluation of humoral response and protective efficacy of two inactivated vaccines against bluetongue virus after vaccination of goats

Bluetongue serotype 8 has become a major animal health issue in the European Union and the European member States have agreed on a vaccination strategy, which involves only inactivated vaccines. In this study, the efficacy of two inactivated vaccines against bluetongue virus serotype 8 (BTV-8) used in Europe since 2008, BTVPUR ALSAP ® 8 (MERIAL) and BOVILIS ® BTV8 (Intervet/SP-AH), was evaluated in goats immunized and challenged with BTV-8 field isolates under experimental conditions. Serological, virological and clinical examinations were conducted before and after challenge. Three groups of 10 goats each (groups A, B and C) were randomly constituted and 2 groups (A and C) were subcutaneously vaccinated twice with one dose of the two commercial vaccines BTVPUR ALSAP 8 (group A) or BOVILIS BTV8 (group C) respectively. Animals of the groups A, C and B (B: controls) were challenged with a virulent inoculum containing BTV-8. During the experiment, it was found out that the BTV-8 challenge inoculum was contaminated with another BTV serotype. However, results demonstrated that vaccination of goats with two injections of BTVPUR ALSAP 8 or BOVILIS BTV8 provided a significant clinical protection against a BTV-8 challenge and completely prevented BTV-8 viraemia in all vaccinated animals. Qualitative data showed no difference in the kinetics and levels of the humoral response induced by these two inactivated vaccines.

A goat poxvirus-vectored peste-des-petits-ruminants vaccine induces long-lasting neutralization antibody to high levels in goats and sheep

Recombinant capripoxvirus (CPV) is a promising candidate differentiating infected from vaccinated animals (DIVA) vaccine against peste-des-petits-ruminants (PPR). In order for recombinant CPV to be successfully used in the field, there should exist dependable indicators for quality control of vaccine products, surveillance and vaccination evaluation. Viral neutralization antibody (VNA) is correlated to protection against PPR and is a technically feasible indicator for this purpose. The immunogenicity of this vectored vaccine in goats and sheep, however, has not been fully evaluated. In this study, we generated two recombinant CPV viruses, rCPV-PPRVH and rCPV-PPRVF, that express PPR virus (PPRV) glycoproteins H and F, respectively. Vaccination studies with different dosages of recombinant viruses showed that rCPV-PPRVH was a more potent inducer of PPRV VNA than rCPV-PPRVF. One dose of rCPV-PPRVH was enough to seroconvert 80% of immunized sheep. A second dose induced significantly higher PPRV VNA titers. There was no significant difference in PPRV VNA responses between goats and sheep. Subcutaneous inoculation also induced a significant PPRV VNA response. PPRV VNA could be detected for over 6 months in more than 80% of vaccinated goats and sheep. Boost vaccination at 6-month intervals induced significant re-boost efficacy of PPRV VNA in goats and sheep. More over, two doses of rCPV-PPRVH could completely overcome the interference caused by pre-existing immunity to the CPV vaccine backbone in animals. Vaccination with rCPV-PPRVH also protected goats from virulent CPV challenge. Our results demonstrate that VNA can serve as a dependent indicator for effective vaccination and immune protection of animals in the field. The recombinant CPV vaccine used in our studies could be a practical and useful candidate DIVA vaccine in countries where PPR newly emerges or where stamp-out plans are yet to be implemented.