Vaccine development in horses involves the creation and refinement of immunizations to protect equine populations from infectious diseases. This process includes identifying antigens, formulating vaccines, and evaluating their safety and efficacy through clinical trials. Vaccines stimulate the horse's immune system to recognize and combat specific pathogens, thereby reducing the incidence and severity of diseases. Common equine vaccines target diseases such as equine influenza, tetanus, and West Nile virus. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, challenges, and advancements in vaccine development for equine health.
Matsumura T, O'Callaghan DJ, Kondo T, Kamada M.The virulence of the cell culture adapted KyA strain of equine herpesvirus type 1 (EHV-1), which lacks at least six genes by deletions in its genome, was assessed by intranasal inoculation of six young horses that were serologically negative for EHV-1. No horses showed clinical signs, and a neutralizing antibody response against EHV-1 was detected in two horses which had antibodies against EHV-4 prior to the inoculation. A challenge experiment using a highly virulent strain of EHV-1 conducted 4 weeks later against 4 of the 6 horses inoculated intranasally with the KyA strain and 2 control hors...
Chirnside ED, Francis PM, Mumford JA.A series of recombinant fusion proteins derived from equine arteritis virus (EAV) open reading frame (ORF) 7 have been used to define the immunoreactive region of the viral nucleocapsid (N) protein. Reactivities of recombinant N fusion proteins with post-infection equine sera in immunoblots and ELISAs indicate that the major nucleocapsid protein epitope is located within amino acid residues 1-69. In ELISAs two recombinant nucleocapsid fusion proteins containing residues 1-69 (rN1-69) and 1-28 (rN1-28) discriminated between pre- and post-infection, and pre- and post-vaccination serum samples. A...
Laviada MD, Roy P, Sánchez-Vizcaíno JM, Casal JI.Segment 10 of the double-stranded RNA (dsRNA) genome from African horse sickness virus serotype 4 (AHSV-4) was cloned and sequenced. The sequence of the coding region showed a total length of 667 bp. Nucleotide comparisons showed a 95% sequence similarity between serotypes 4 and 9, and 76% between serotypes 4 and 3. cDNA clones containing the coding region were cloned in the vector pET3xb and expressed in Escherichia coli. The NS3 gene product was synthesised at very high level as an insoluble fusion protein. The recombinant protein was used in a differential ELISA to distinguish horses that w...
Wallace FJ, Emery JD, Cripps AW, Husband AJ.The ability of mucosally administered antigen to provide protection against Streptococcus equi ('Strangles') infections in horses was examined. First, an enzyme linked immunosorbent assay (ELISA) was developed to detect the immune status of horses to S. equi. This assay was used to select Strangles-naive horses for the study and also to monitor their response to immunisation. Potential vaccine candidates were: (a) orally administered paraformaldehyde killed S. equi; (b) intraperitoneally (IP) administered paraformaldehyde killed S. equi in a non-inflammatory adjuvant; (c) orally administered l...
Whalley JM, Love DN, Tewari D, Field HJ.A series of recombinant baculoviruses containing genes for glycoproteins C, D, H and L of equine herpesvirus 1 (EHV-1) have been constructed, and the EHV-1 products characterised by gel electrophoresis and immunoblotting. The EHV-1 glycoproteins expressed in insect cells were similar but not identical in apparent sizes to those expressed in EHV-1 infected mammalian cells. Each of the EHV-1 products was recognised by convalescent equine sera, indicating that they were all targets for an equine immune response. Mice immunised with baculovirus-expressed EHV-1 gD and gC acquired an enhanced abilit...
Chirnside ED, de Vries AA, Mumford JA, Rottier PJ.Complementary DNAs encoding ORFs 2 to 7 equine arteritis virus (EAV) have been cloned into the expression vector pGEX to produce glutathione-S-transferase fusion proteins. Recombinant proteins were affinity purified and screened in ELISA with equine sera to identify immunoreactive polypeptides. The large envelope glycoprotein (GL) was identified as the most reactive to EAV-positive equine sera and an immuno-dominant epitope was mapped between amino acids 55 and 98 by subcloning and expression. A fusion protein covering this region and a GL-specific synthetic peptide (residues 75 through 97) in...
Frayne J, Stokes CR.The use of tetanus toxoid as a recall antigen to investigate equine immune responses would be, in theory, a useful and cost-effective model in vitro. However, by using various regimens for culturing peripheral blood mononuclear cells from horses previously immunised with toxoid no proliferative response to the antigen was obtained in vitro, whereas lymph node mononuclear cells from the same animals proliferated significantly in response to it. The lack of response by the peripheral blood mononuclear cells was not due to the presence of a suppressive factor but to a lack of recognition of the a...
Chirnside ED, Francis PM, de Vries AA, Sinclair R, Mumford JA.A recombinant glutathione-S-transferase fusion protein expressing amino acids 55-98 of equine arteritis virus (EAV) GL (rGL 55-98) was tested in an ELISA for its ability to detect serum antibodies to EAV. Host antibodies induced following EAV infection bound the recombinant antigen by ELISA. The ELISA specificity and sensitivity were determined with a panel of equine sera including postinfection and postvaccination samples. A good correlation existed between EAV neutralizing antibody titers and ELISA absorbance values (r = 0.827). The sensitivity and specificity of the ELISA were 99.6 and 90.1...
Hunt AR, Roehrig JT.In order to define more precisely the protective epitope encoded within the first 25 amino acids (aa) of the E2 glycoprotein of the Trinidad donkey strain of Venezuelan equine encephalomyelitis (VEE) virus, we examined the immunogenicity of smaller peptides within the first 19 aa. pep1-9 and pep3-10 elicited virus-reactive antibody, but failed to protect mice from virus challenge. Additionally, pep3-10 was identified by a competitive binding assay using overlapping peptide octamers as the putative binding site of the antipeptide monoclonal antibody (mAb) 1A2B-10. Since the E2 amino-terminal se...
Sekiguchi K, Sugita S, Fukunaga Y, Kondo T, Wada R, Kamada M, Yamaguchi S.A polymerase chain reaction (PCR) based assay capable of detecting and differentiating seven strains of equine arteritis virus (EAV) from around the world was developed. The primers for the PCR were chosen from the ORF6 gene encoding the unglycosylated membrane protein (M). Viral RNA from cell culture fluids infected with each of the seven EAV strains and RNA from the live vaccine, Arvac, was detected by PCR using four sets of primers. The sensitivity of detection was increased from 100 to 1,000 times by performing nested PCR enabling the detection of RNA at a level of 0.5-5 PFU. Differentiati...
Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA.Twelve adult ponies and 2 conventional foals were exposed to 10(6.6) TCID50 of Equid herpesvirus-1 (EHV-1), strain Ab4 and samples of respiratory tract tissues were recovered. Infectious virus in tissue homogenates was detected using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry of paraffin sections. The results illustrated the rapid dissemination of EHV-1 throughout the respiratory tract, with early replication in the lungs one day after exposure. Endothelial cell infection was prominent in all areas of the nasopharyn...
Burrage TG, Laegreid WW.African horsesickness (AHS) is a serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family Reoviridae. In horses, AHS causes three distinct clinicopathologic syndromes, the pulmonary, cardiac and fever forms of the disease. Recent work has shown that the primary determinant of the form of disease expressed by naive horses is the virulence of the virus inoculum. Horses which recover from AHS exhibit solid humoral immunity against homologous challenge. Protective antibodies appear to be directed towards neutralizing epitopes on AHS virus VP...
McGuire TC, O'Rourke KI, Baszler TV, Leib SR, Brassfield AL, Davis WC.Cells infected with vaccinia viruses expressing the equine infectious anaemia virus (EIAV) gag gene (VGag) or gag plus the 5' pol encoding protease (VGag/PR) were evaluated with monoclonal antibody to a p26 capsid protein linear epitope (QEISKFLTD). Both recombinant viruses expressed Gag precursor protein (55K) whereas only VGag/PR expressed a detectable Gag-Pol fusion protein (82K) with a functional protease, shown by subviral particles containing processed p26. Horses inoculated with VGag/PR produced antibodies reactive with EIAV Gag proteins.
Mumford JA, Wilson H, Hannant D, Jessett DM.Equine influenza vaccines containing inactivated whole virus and Carbomer adjuvant stimulated higher levels and longer lasting antibody to haemagglutinin in ponies than vaccines of equivalent antigenic content containing aluminium phosphate adjuvants. Five months after the third dose of vaccine containing Carbomer adjuvant, ponies were protected against clinical disease induced by an aerosol of virulent influenza virus (A/equine/Newmarket/79, H3N8). In contrast ponies which received vaccine containing aluminium phosphate adjuvant were susceptible to infection and disease. There was an inverse ...
Wang SZ, Rushlow KE, Issel CJ, Cook RF, Cook SJ, Raabe ML, Chong YH, Costa L, Montelaro RC.The potential for antibody-dependent enhancement of replication of macrophage/monocyte tropic viruses has posed a significant problem in the development of vaccines for several animal and human viruses and has raised significant concern in the design of potential AIDS vaccines. Using the previously described equine infectious anemia virus/Shetland pony system as a model for HIV-1 vaccine development, we have evaluated the efficacy of a recombinant subunit vaccine containing a baculovirus-expressed envelope surface glycoprotein (gp90) of EIAV. The results of these trials demonstrate not only th...
Roehrig JT.The equine encephalitis viruses are members of the genus Alphavirus, in the family Togaviridae. Three main virus serogroups represented by western (WEE), eastern (EEE) and Venezuelan equine encephalitis (VEE) viruses cause epizootic and enzootic infection of horses throughout the western hemisphere. All equine encephalitis viruses are transmitted through the bite of an infected mosquito. The first equine encephalitis virus vaccines were produced by virus inactivation. Problems with inadequate inactivation, which may have caused a major epidemic/epizootic of VEE in central America and Texas in ...
Dowsett KF, Tshewang U, Knott LM, Jackson AE, Trigg TE.A series of experiments using an ovalbumin conjugated gonadotrophin releasing hormone was used to stimulate antibody production, suppress testosterone secretion and depress testicular function in yearling and 2 year old colts and fillies. In the preliminary experiment, an injectable oil-based formulation was administered to yearling colts. Testicular development and testosterone secretion were retarded for a period of approximately 28-32 weeks while antibody titres were greater than 1:1000. An implant and water-soluble vaccine (200 and 400 mg) is presently being tested in 2 year old colts. Tes...
Sviatchenko VA, Agapov EV, Urmanov IKh, Serpinskiĭ OI, Frolov IV, Kolykhalov AA, Ryzhikov AB, Netesov SV.A recombinant strain of vaccinia virus (VR26) containing a DNA-copy of the subgenomic 26S RNA of Venezuelan equine encephalomyelitis virus (VEE) inserted into the coding region of thymidine kinase (TK) gene was produced. This subgenomic RNA contained the genes for all structural proteins of the VEE virus, the strain Trinidad donkey (TRD). VR26 effectively expressed VEE virus glycoproteins on the membranes of the infected cells. Blood sera of VR26-immunized animals were found to contain VEE virus-specific antibodies. VR26-immunized mice and rabbits showed a high level of resistance to subcutane...
Sellon DC.The ability of EIAV to persistently infect horses in the face of a profound immune response by the host makes it a potentially devastating disease for the horse population of the United States. Its ability to evade host immune defenses by lying dormant in apparently healthy animals and by rapidly changing its antigenic determinants is proving to be a major obstacle to vaccine development. Because most infected horses appear clinically normal and a large proportion of horses in this country remain untested, the virus is not likely to be eradicated in the near future. Yet, for the same reason, b...
Wilson WD.Influenza continues to be one of the most important diseases of horses despite the availability and widespread use of equine influenza vaccines for almost 30 years. In recent years, infection with the influenza A/equine/2 subtype has become endemic in the equine populations of North America, Europe, and Scandinavia. Continued antigenic drift of field virus has compromised the efficacy of vaccines, most of which contain antigens prepared from influenza viruses isolated more than 10 years ago. This article reviews the history, virology, epidemiology, pathogenesis, immunology, clinical presentati...
Oxburgh L, Berg M, Klingeborn B, Emmoth E, Linné T.The antigenic properties of H3N8 equine influenza virus from the Swedish epizootic of 1991 differ from those of A/eq 2/Fontainebleau/79 (representative of the Swedish vaccine strain) in hemagglutination inhibition tests. The amino acid sequence of the hemagglutinin (HA) of an isolate from the 1991 outbreak was deduced from the nucleotide sequence and comparison was made to the A/eq 2/Fontainebleau/79 strain. Twenty-three amino acid substitutions were found, 10 mapping onto areas of the HA known to bind antibodies in human H3 influenza viruses. The amino acid changes together with the serologic...
Slater JD, Gibson JS, Field HJ.Both intranasal (i.n.) and intracerebral (i.c.) inoculation of mice with wild-type equine herpesvirus type 1 (wt EHV-1) caused clinical signs and mortality. Virus could be recovered from target organs (turbinates, lungs and blood) for several days. By contrast, the thymidine kinase (TK)-deficient deletion mutant PR1 produced markedly less clinical disease following both i.n. and i.c. inoculation, and, in particular, no mortality occurred. PR1 did, however, establish productive infections following either route of inoculation. High titres of virus were recovered from target organs although viru...
Jaeschke G, Lange W.In this paper three outbreaks of equine influenza in Berlin (Germany) in the years of 1988, 1989 and 1991 are discussed, reporting mainly clinical, hematological, virological and some epizootiological aspects. We have detected variations from the traditional pattern of equine influenza, whereby the main clinical symptoms like cough or fever were absent in several cases. If cough was found, it was moist. Furthermore a mucous nasal discharge was present in a number of cases for a period of 4-5 days. Extreme neutropenia, lymphocytosis and predominantly an unchanged level of monocytes were observe...
House JA.African horse sickness (AHS), which causes mortality up to 95%, is caused by orbiviruses and is transmitted by Culicoides. The goal of a control and eradication program for AHS is to prevent the spread of the virus via the biological vector. Control measures include slaughter of infected animals, housing of suspected infected animals in insect-proof stalls, and vaccination. Vaccination has played a key role in eradication when AHS occurred outside of Africa. Both modified live vaccines (MLV) and inactivated vaccines have been used to control AHS. An acceptable vaccine should be: safe, efficaci...
Binns MM, Daly JM, Chirnside ED, Mumford JA, Wood JM, Richards CM, Daniels RS.The haemagglutinin (HA) gene from the equine influenza H3N8 isolate Suffolk/89 has been cloned by reverse transcription and polymerase chain reaction amplification. The nucleotide sequence of the HA gene was determined from two independently cloned copies of the gene and was found to be most closely related to recent American isolates supporting the idea that most isolates of equine H3N8 are evolving as a single lineage. When the predicted amino acid sequence of the Suffolk/89 HA was examined, changes had taken place in at least four of the major antigenic sites, A, B, C, and D when compared t...
Webster RG, Thomas TL.A new H3N8 equine influenza virus [A/Equine/Jilin/1/89 (Eq/Jilin)] appeared in Northeastern China in 1989 and caused high mortality in horses; the available evidence indicates that it has not yet spread outside this region of the world. Serological analysis with postinfection ferret sera in haemagglutination inhibition (HI) tests confirmed that Eq/Jilin is antigenically distinct from H3N8 equine influenza viruses isolated between 1963 and 1991 and also showed that a current equine influenza virus [A/Equine/Alaska/1/91 (H3N8)] had undergone antigenic drift. In the present study we determine if ...
Tewari D, Gibson JS, Slater JD, O'Neill T, Hannant D, Allen GP, Field HJ.EHV-1 was inoculated into specific pathogen-free (SPF) foals in order to study uncomplicated primary responses. Infection resulted in a strong serological response recognizing EHV-1-specific antigens; this contrasts with a previous publication where a weak response was recorded in SPF animals. Antibodies to EHV-1 were readily detected by four techniques (virus neutralization, complement fixation, Western blots and immune precipitation), yet there was comparatively little cross-reaction to EHV-4 target antigen. Re-inoculation with the same virus strain stimulated antibodies to EHV-1 but no addi...
Kinney RM, Tsuchiya KR, Sneider JM, Trent DW.Venezuelan equine encephalitis (VEE) virus is a mosquito-borne pathogen that has caused encephalitis in equine species and humans during sporadic outbreaks in the western hemisphere. The last, and most widespread, VEE outbreak occurred in South America, Central America, Mexico and the U.S.A. (Texas) during 1969 to 1972. We have cloned and sequenced the genome of a virulent VEE subtype I-AB virus, strain 71-180, isolated in Texas in 1971. Thirty-four nucleotide differences were detected between the genome of 71-180 virus and that of the subtype I-AB Trinidad donkey (TRD) virus isolated during t...
Chambers TM.A novel strain of equine influenza virus, influenza A/equine/Jilin (China)/1/89, has emerged which is genetically distinct from all earlier strains of equine influenza. It is therefore possible that the vaccines against equine influenza may be unable to protect horses against disease caused by this virus strain. In vitro serological assays established that there were low levels of immunological cross-reactivity between the new virus, the current vaccine strains and the strains of equine-2 influenza virus now in circulation.
Epp T, Waldner C, Leighton FA, Berke O, Townsend HG.The primary objectives of this study were to determine the seroprevalence of West Nile virus (WNV) infection of horses in Saskatchewan in 2003 and to identify risk factors for the infection. Blood samples were collected in August and October from 212 horses in 20 herds in 5 geographic zones. After accounting for within-herd clustering, the proportion of horses that had been infected with WNV, as determined by IgG and IgM antibody response, was 55.7% (95% confidence interval, 44.9% to 65.8%). The proportion of antibody-positive horses differed among herds (0% to 100%) and across ecoregions (20%...
Carnet F, Paillot R, Fortier C, Hue ES, Briot L, de Geoffroy F, Vidalain PO, Pronost S.Equine influenza virus (EIV) is responsible for recurring outbreaks that are detrimental to the equine industry. Vaccination is key for prevention, but the effectiveness and duration of protection provided by existing vaccines is often insufficient. In order to improve vaccine efficacy, we evaluated the benefit of immune stimulation with inactivated Parapoxvirus ovis (iPPVO) on the antibody response induced by a vaccine boost against EIV. A whole inactivated ISCOMatrix-adjuvanted equine influenza vaccine was administered alone ( = 10) or combined with iPPVO injections at D0, D2 and D4 post vac...
Joonè CJ, Nolan MB, Bertschinger HJ, Schulman ML.A sequence of studies is reviewed that reported the domestic horse (Equus caballus) mare as an appropriate and accessible research platform for recording clinical and laboratory data post-immunisation with anti- GnRH and -zona pellucida (ZP) immunocontraceptive vaccines. Experience with a native porcine ZP (pZP) vaccine in African elephant (Loxodonta africana) cows highlighted needs for improving vaccine formulations and more clearly defining associated ovarian effects and safety profiles. Initially, the efficacy, reversibility and safety of the GnRH vaccine Improvac® in mares was demonstrate...
Jansen BC, Knoetze PC.An intramuscular injection of 8-16 Lf tetanus toxoid in water-in-oil emulsion protected adult horses against tetanus for at least 128 weeks. A booster dose of 8 Lf toxoid in aqueous solution protected them for a further period of at least 3 1/2 years. Colostral immunity protected foals for at least 10 weeks. An intramuscular injection of 8 Lf toxoid in water-in-oil emulsion given to foals from immune dams when they were 10-18 weeks old did not elicit any antibody response. They did respond, however, to a booster injection of 8 Lf toxoid in aqueous solution given 12 weeks after the first dose. ...
Edmonds JD, Horohov DW, Chapmat MR, Pourciau SS, Antoku K, Snedden K, Klei TR.This study was performed to test the hypothesis that immunity to heterologous vaccination would improve when the parasites were removed. It was also expected that parasitised ponies would exhibit a biased Th2 cytokine response to KLH immunisation. Helminth parasites are common in horses even in the era of highly effective broad-spectrum antiparasiticides. These parasites have been shown to alter the outcome to heterologous immunisation in a number of host species. The effect of gastrointestinal parasites on heterologous vaccination has not been addressed in equids. In the current study, humora...
Appleton JA, Gagliardo LF.A large panel of mouse monoclonal antibodies was produced and tested against field isolates of the equine H7N7 influenza A virus subtype. Only a limited degree of H7 haemagglutinin variation was detected. At least four antigenic sites were identified by selecting variant viruses in eggs. The limited variation in the field did not correlate with the frequency of variant viruses detected in eggs; this frequency was similar to those reported for other influenza viruses. We sought to determine whether the limited amount of variation could be correlated with an epitope-restricted antibody response ...
Schnabel CL, Steinig P, Koy M, Schuberth HJ, Juhls C, Oswald D, Wittig B, Willenbrock S, Murua Escobar H, Pfarrer C, Wagner B, Jaehnig P, Moritz A....Deoxyribonucleic acid (DNA) vaccines are used for experimental immunotherapy of equine melanoma. The injection of complexed linear DNA encoding interleukin (IL)-12/IL-18 induced partial tumour remission in a clinical study including 27 grey horses. To date, the detailed mechanism of the anti-tumour effect of this treatment is unknown. Results: In the present study, the clinical and cellular responses of 24 healthy horses were monitored over 72 h after simultaneous intradermal and intramuscular application of equine IL-12/IL-18 DNA (complexed with a transfection reagent) or comparative substanc...
Sullivan E, Lecollinet S, Kerviel A, Hue E, Pronost S, Beck C, Dumarest M, Zientara S, Roy P.African horse sickness virus (AHSV) is an Orbivirus within the Reoviridae family, spread by Culicoides species of midges, which infects equids with high mortality, particularly in horses and has a considerable impact on the equine industry. In order to control the disease, we previously described Entry Competent Replication Abortive (ECRA) virus strains for each of the nine distinct AHSV serotypes and demonstrated their potential as vaccines, first in type I interferon receptor (IFNAR-/-) knockout mice, and then in ponies. In this report we have investigated whether or not a combination ECRA v...
Kropich-Grant JN, Wiley KE, Manyweathers J, Thompson KR, Brookes VJ.Hendra virus disease (HeVD) is an emerging zoonosis in Australia, resulting from the transmission of Hendra virus (HeV) to horses from Pteropus bats. Vaccine uptake for horses is low despite the high case fatality rate of HeVD in both horses and people. We reviewed evidence-based communication interventions to promote and improve HeV vaccine uptake for horses by horse owners and conducted a preliminary evaluation of potential drivers for HeV vaccine uptake using the Behavioural and Social Drivers of Vaccination (BeSD) framework developed by the World Health Organization. Six records were eligi...
Oxburgh L, Berg M, Klingeborn B, Emmoth E, Linné T.The antigenic properties of H3N8 equine influenza virus from the Swedish epizootic of 1991 differ from those of A/eq 2/Fontainebleau/79 (representative of the Swedish vaccine strain) in hemagglutination inhibition tests. The amino acid sequence of the hemagglutinin (HA) of an isolate from the 1991 outbreak was deduced from the nucleotide sequence and comparison was made to the A/eq 2/Fontainebleau/79 strain. Twenty-three amino acid substitutions were found, 10 mapping onto areas of the HA known to bind antibodies in human H3 influenza viruses. The amino acid changes together with the serologic...
Paillot R, Regourd E, Behr-Gross ME.Equine influenza (EI) is an important respiratory disease of horses, with welfare and economic consequences. Vaccination remains one of the most efficient prevention methods available. Equine influenza virus (EIV) is constantly evolving and consequently EI vaccines need to be updated on a regular basis. In 2010, the World Organisation for Animal Health (OIE) Expert Surveillance Panel (ESP) on EI provided a new recommendation for EI vaccine strain composition, including the incorporation of representative EIV strains of both Florida Clade 1 and Clade 2 sub-lineages (FC1 and FC2, respectively). ...
Wernery U, Rodriguez M, Raghavan R, Syriac G, Miriam Thomas M S, Elizabeth SK, Federico Ronchi G, Muhammed R, Patteril NA, Joseph S.African horse sickness (AHS) is a devastating viral disease of equids that was first recorded in 1327. Currently, prevention and control of the disease are based on attenuated vaccines and midge control. It has been shown that attenuated Orbivirus vaccines are not always safe as they may reverse to virulence. Objective: In the Emirate of Dubai, a vaccination experiment was carried out with an inactivated AHS vaccine produced at the Central Veterinary Research Laboratory (CVRL), Dubai, UAE to investigate the humoral antibody response of AHS-naïve horses to this vaccine. Our vaccination experim...
Kirkpatrick JF, Liu IM, Turner JW, Bernoco M.Twenty-six free-roaming feral mares were immunized against porcine zonae pellucidae (PZP) between February and May, 1988. Eight sexually mature mares received 2 inoculations 2 weeks apart, and 18 mares received 3 inoculations at intervals of 2 and 4 weeks. Analysis of urinary oestrone conjugates (E1C) and non-specific progesterone metabolites (iPdG) in samples collected in October, 1988, revealed that none of the 18 mares that received 3 and only 1 of the 6 mares that received two inoculations were pregnant, whereas 3 of 6 sham-injected control mares and 5 of 11 untreated mares were pregnant. ...
Frayne J, Stokes CR.The use of tetanus toxoid as a recall antigen to investigate equine immune responses would be, in theory, a useful and cost-effective model in vitro. However, by using various regimens for culturing peripheral blood mononuclear cells from horses previously immunised with toxoid no proliferative response to the antigen was obtained in vitro, whereas lymph node mononuclear cells from the same animals proliferated significantly in response to it. The lack of response by the peripheral blood mononuclear cells was not due to the presence of a suppressive factor but to a lack of recognition of the a...
Fontanals AM, Becú T, Polledo G, Gaskin CK, Braun M.An R. equi vaccine, prepared under conditions which induce the expression of many antigens, and which has given encouraging results in field trials, was analyzed by SDS-PAGE and immunoblots and compared with other R. equi preparations: a preparation made in with the same technique from a nonvirulent isolate (virulence associated protein negative, VapA-negative); a whole cell preparation of a VapA-positive R. equi, prepared as a standard bacterin; and a semipurified VapA preparation (APTX). The antigens in these preparations were analyzed using hyperimmune sera (from adult horses vaccinated wit...
Fukunaga Y, Wada R, Imagawa H, Kanemaru T.Venereal infection with equine arteritis virus (EAV) was established in each of seven mares by inoculation via the cervix with 20 ml of viral suspension (> or = 8 x 10(6) plaque-forming units; PFU), following treatment with prostaglandin and oestradiol. A dose of < or = 8 x 10(5) PFU produced infection in only five of eight mares. Serum neutralizing antibody developed in mares manifesting clinical signs of equine viral arteritis (EVA), and a weak antibody was detectable in one apparently healthy mare inoculated with 8 x 10(5) PFU. Virus isolation was demonstrated not only in the buffy coat but...
Weerasinghe CU, Learmonth GS, Gilkerson JR, Foote CE, Wellington JE, Whalley JM.The envelope glycoprotein D of EHV-1 (EHV-1 gD) is essential for virus infectivity and entry of virus into cells and is a potent inducer of virus-neutralizing antibody. In this study, truncated EHV-1 gD (gDt) was expressed with a C-terminal hexahistidine tag in E. coli using a pET vector. Western blot analysis using an anti-gD monoclonal antibody demonstrated the presence of gDt bands at 37.5, 36, 29.5 and 28 kDa. The immunogenicity and protective efficacy of partially purified gDt was compared with gD expressed in insect cells by a recombinant baculovirus (Bac gD) using a BALB/c mouse model o...
Han X, Zhang P, Yu W, Xiang W, Li X.The Chinese EIAV vaccine is an attenuated live virus vaccine obtained by serial passage of a virulent horse isolate (EIAV) in donkeys (EIAV) and, subsequently, in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV) with attenuated strains serially passaged in donkey MDM (EIAV) and donkey dermal cells (EIAV). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, designated g5, g9, and g1...
Pusterla N, Jackson R, Mapes SM, Noland J, Stenbom RM, Gebhart C.The humoral immune response and fecal shedding of Lawsonia intracellularis was investigated in 20 weanling foals following intra-rectal administration of frozen-thawed or lyophilized avirulent live L. intracellularis vaccine. Foals received either 30 mL frozen-thawed or lyophilized vaccine intra-rectally, given twice, 4 weeks apart. Serum samples from each foal were collected every 4 weeks for 16 weeks following the first vaccination and tested for anti-L. intracellularis specific IgG by immunoperoxidase monolayer assay. Rectal swabs were collected every other day following the first vaccinati...
Ohta M, Bannai H, Nemoto M, Kambayashi Y, Tamura N, Tsujimura K.An inactivated equine influenza virus (EIV) vaccine and a live equine herpesvirus type 1 (EHV-1) vaccine are usually administered concurrently to Thoroughbred racehorses in Japan. The objective of this study was to evaluate whether concurrent administration of an inactivated EIV vaccine and a live EHV-1 vaccine in Thoroughbred racehorses influences the antibody response against EIV. We compared the antibody response against EIV in horses administered both vaccines on the same day (Group A; n = 27) and the response in horses administered an inactivated EIV vaccine first and then a live EHV-1 v...
Prutton JSW, Barnum S, Pusterla N.Equine coronavirus (ECoV) is considered an emerging enteric virus with reported morbidity rates ranging from 10 to 83% and fatality rates ranging from 7 to 27% in adult horses; a vaccine for ECoV is currently not available. This study investigated the safety, humoral response and viral shedding in horses inoculated with a commercially available modified-live bovine coronavirus (BCoV) vaccine. Twelve healthy adult horses were vaccinated twice, 3 weeks apart, either orally, intranasally or intrarectally. Two healthy unvaccinated horses served as sentinel controls. Following each vaccine adminis...
Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W.The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, desig...
Arora S, Sharma S, Goel SK, Singh US.Implementation of the recommended post-exposure prophylaxis by vaccination and specific immunoglobulin therapy for rabies is largely hampered by its high cost and inadequate production. Therefore, the development and availability of an economic preparation of rabies immunoglobulin is a high priority for India, where rabies is a major cause of death. We studied the efficacy of four different adjuvants in raising antibodies to rabies antigen in older, discarded equines. Methods: Eleven equines, 23-26 years old, were divided into 4 groups to receive four different adjuvants in small amounts (1-2 ...
Reemers S, van Bommel S, Cao Q, Sutton D, van de Zande S.Equine influenza virus (EIV) is a major cause of respiratory disease in horses. Vaccination is an effective tool for infection control. Although various EIV vaccines are widely available, major outbreaks occurred in Europe in 2018 involving a new EIV H3N8 FC1 strain. In France, it was reported that both unvaccinated and vaccinated horses were affected despite >80% vaccination coverage and most horses being vaccinated with a vaccine expressing FC1 antigen. This study assessed whether vaccine type, next to antigenic difference between vaccine and field strain, plays a role. Horses were vaccin...
Frosth S, Morris ERA, Wilson H, Frykberg L, Jacobsson K, Parkhill J, Flock JI, Wood T, Guss B, Aanensen DM, Boyle AG, Riihimäki M, Cohen ND....Streptococcus equi subspecies equi (S equi) is the cause of Strangles, one of the most prevalent diseases of horses worldwide. Variation within the immunodominant SeM protein has been documented, but a new eight-component fusion protein vaccine, Strangvac, does not contain live S equi or SeM and conservation of the antigens it contains have not been reported. Objective: To define the diversity of the eight Strangvac antigens across a diverse S equi population. Methods: Genomic description. Methods: Antigen sequences from the genomes of 759 S equi isolates from 19 countries, recovered between 1...
Olitsky PK, Long PH.The virus of vesicular stomatitis is not readily killed by formalin. This chemical is one of a group which coagulates the proteins of the medium in which the virus is usually contained. It has already been found(7) that other reagents of the protein-coagulating group are not actively virucidal) and the effect of formalin in this instance is therefore characteristic of the group. The so called formalinized vaccines which give rise to immunity can be shown to have done so because of the presence of living virus. A single injection of such so called "vaccine," or of other material containing livi...
Plowright W.An account is presented of the development and use of herpesvirus vaccines in domestic animals, with particular reference to those viruses causing cytolytic rather than oncogenic infections. The chief infections covered are Aujeszky's disease (AD or pseudorabies), infectious bovine rhinotracheitis (IBR) and equine rhinopneumonitis (equine abortion; EHV-1). Others mentioned are feline viral rhinotracheitis and malignant catarrhal fever of cattle. Both live-modified and inactivated vaccines are widely used or under development for ADV, IBR and EHV-1. Live vaccines are generally regarded as succe...
AbdelKhalek A, Ostafe R, Olave C, HogenEsch H, Turner JW.Immunization with porcine zona pellucida (PZP) proteins is being used successfully to induce infertility in wildlife including horses. However, widespread adoption of this method to control the growth of horse populations requires further refinement in order to induce long-term infertility, reduce the frequency and severity of injection site reactions, and make the vaccines easier to administer. The next generation of PZP-based vaccines will likely be a controlled-release formulation with different adjuvants from the Freund's adjuvants used in existing vaccines. We evaluated the response of eq...
van der Kolk JH, de Groot J.Serological surveys showed that equine monocytic ehrlichiosis (EME) occurs in the USA, Canada and Europe. The causative agent is Rickettsia Ehrlichia risticii, isolated for the first time in 1984. The clinical features of the disease are sluggishness, anorexia, colic and fever, possibly followed by watery diarrhoea. Complications of an infection with E. risticii are laminitis and abortion. Colitis of the ascending colon may be observed at autopsy. Following a positive serological diagnosis (IgM ELISA) of EME, treatment with oxytetracycline can be initiated. It is also important to restore the ...
