Topic:Immunization
Immunization in horses involves the administration of vaccines to stimulate an immune response, thereby providing protection against specific infectious diseases. Vaccines commonly used in equine medicine include those for equine influenza, tetanus, and West Nile virus. The process of immunization aims to prepare the horse's immune system to recognize and combat pathogens upon exposure. Vaccination schedules and protocols may vary based on factors such as age, health status, and regional disease prevalence. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, efficacy, and considerations of immunization practices in equine health.
Prevention of rotavirus diarrhoea in foals by parenteral vaccination of the mares: field trial. Many countries have reported rotavirus diarrhoea in foals. In Argentina it causes important economic losses to the horse industry. In this work we present the results obtained using an experimental vaccine in a farm with enzootic infection of rotavirus. A hundred mares were vaccinated 60 and 30 days before foaling with inactivated rotavirus SA11 (G3P2), H2 (G3P12), Lincoln (G6P1), with aluminum hydroxide as adjuvant; 65 mares were included in the unvaccinated, control group. To evaluate the vaccine, morbidity, duration of the diarrhoea and rotavirus shedding were recorded. Antibody levels were...
Affinity purification and characterization of a fibrinogen-binding protein complex which protects mice against lethal challenge with Streptococcus equi subsp. equi. Cell-wall-associated proteins from Streptococcus equi subsp. equi, the causative agent of strangles, were analysed with a view to identifying a potential protective antigen. Preparations of these proteins, isolated from mutanolysin extracts of cell walls, were shown to contain one major high-M(r) protein species (apparent M(r) 220,000 and 550,000 when analysed by SDS-PAGE and gel-filtration chromatography, respectively). The high-M(r) protein bound horse fibrinogen and was purified under non-denaturing conditions using fibrinogen affinity chromatography. The fibrinogen-binding protein (FgBP) r...
An outbreak of foal yersiniosis in Poland: pathological and bacteriological examination. In the springtime of 1995, 10 per cent of foals at a stud-farm died due to suppurative lesions. Three dead foals were examined. The manifestations of watery diarrhoea and pneumonia were observed. A profuse growth of an enterotoxigenic strain of Yersinia pseudotuberculosis was obtained from the internal organs of the foals. The foals with clinical symptoms of pneumonia and watery diarrhoea were immunized with Propionibacterium acnes t. II. All mares and their offspring from the stud were treated with an immunomodulator (Propionibacterium acnes t. II) and then vaccinated with a formalin-inactiva...
Interspecific and extraspecific pregnancies in equids: anything goes. Equids possess the unusual ability to interbreed freely among the phenotypically and karyotypically diverse member species of the genus to produce viable, but usually infertile, offspring. The mule (female horse x male donkey) was humanity's first successful attempt at genetic engineering and its clear expression of both parental phenotypes has contributed much to our understanding of genetic inheritance over the centuries. Even more surprising, mares and donkeys have been shown to be capable of carrying to term a range of true, xenogeneic extraspecies pregnancies created by embryo transfer, i...
Preliminary study of ovarian activity in fillies treated with a GnRH vaccine. To investigate the effects of two doses (200 and 400 mg) of a water-soluble gonadotrophin-releasing hormone vaccine on the ovarian activity of 2-year-old fillies. Methods: A controlled vaccination dose rate experiment. Methods: Six 2-year-old Australian Stock Horse fillies were randomly allocated to three treatment groups; unvaccinated controls, those receiving 200 mg of the vaccine and those receiving 400 mg of the vaccine. Results: Ovarian activity of the treated fillies was suppressed at the peak of breeding season while that of untreated controls continued normally. The control fillies dis...
Production of highly potent horse antivenom against the Thai cobra (Naja kaouthia). Naja kaouthia (NK) causes the highest fatality due to snake venom poisoning in Thailand. The specific antivenom produced is of low potency and in short supply. The aim of this study was to improve the antivenom potency. Bentonite and complete Freund's adjuvants (CFA) and various immunogens were compared. Six groups of three to five horses were immunized as follows: Group 1, NK venom adsorbed on bentonite; Group 2, NK venom in CFA; Group 3, NK venom in CFA in multi-emulsion formulation; Group 4, NK venom in 25% CFA; Group 5, NK neurotoxin 3 (NK3) conjugated with tetanus toxoid (NK3-TT) in CFA; ...
Field study of the safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. To determine safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. Methods: Prospective randomized controlled trial. Methods: 316 pregnant Thoroughbred mares during the first year of the study and 311 during the second year. Methods: During the first year, mares received 3 doses of vaccine or placebo, IM, at 8, 9, and 10 months of gestation. Serum neutralizing antibody titers were measured before vaccination and 1 and 35 days after foaling. Antibody titers were measured in foals 1, 7, 35, 60, 90, and 120 days after birth. During the second year, mares that had been v...
Immunogenicity and efficacy of baculovirus-expressed and DNA-based equine influenza virus hemagglutinin vaccines in mice. Two fundamentally different approaches to vaccination of BALB/c mice with the hemagglutinin (HA) of A/Equine/Kentucky/1/81 (H3N8) (Eq/KY) were evaluated, that is, administration of HA protein vs administration of HA-encoding DNA. Each vaccine was tested for its immunogenicity and ability to provide protection from homologous virus challenge. HA protein was synthesized in vitro by infection of Sf21 insect cells with a recombinant baculovirus. Intranasal administration of this vaccine induced virus-specific antibodies, as measured by enzyme-linked immunosorbent assay (ELISA), but did not induce ...
Antigenic analysis of Rhodococcus equi preparations using different horse sera. 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...
Immunoprophylaxis of Rhodococcus equi pneumonia in foals. An immunoprophylaxis program for R. equi infection of foals has been established on a number of thoroughbred breeding farms in Argentina over the past 4 years. Nearly 800 mares annually were immunized subcutaneously during the last 2 months of pregnancy with 2-3 doses of a vaccine containing soluble antigens of R. equi, including the virulence associated protein (VapA) and 'equi factors' exoenzymes. The mortality from R. equi pneumonia in the foals from vaccinated dams dropped from an average of 3% in the 5 years before the vaccination program was initiated to an average of 1.2% in the 4 years...
Protective effect against Rhodococcus equi infection in mice of IgG purified from horses vaccinated with virulence associated protein (VapA)-enriched antigens. IgG was purified from horses immunized with repeated doses of virulence associated (VapA) enriched antigens extracted with Triton X-114 from the surface of a virulent strain of R. equi. This IgG were administered to mice immunosuppressed by prior treatment with indomethacin. Mice administered the higher dose were completely protected against intraperitoneal infection with R. equi; mice given the lower dose were partially protected. By contrast, mice administered concentrated nonimmune equine IgG were not protected. This study demonstrates that VapA may be an important antigen involved in humor...
Tumor necrosis factor-alpha production and disease severity after immunization with enriched major core protein (p26) and/or infection with equine infectious anemia virus. Cardinal features of equine infectious anemia (EIA) include fever, hemolytic anemia and thrombocytopenia during the acute phase of the disease, and cachexia and anemia seen during the chronic phase. These signs are thought to result from the release of inflammatory cytokines such as TNF-alpha. In order to determine if TNF-alpha has a role in the pathogenesis of acute EIA and vaccine-induced disease enhancement, we measured plasma concentrations of TNF-alpha in ponies immunized with virus enriched major core protein-p26 and/or experimentally infected with EIAV. Naturally infected inapparent EIA...
Simulation studies of vaccination strategies in African horse sickness. A simulation model including two hosts (horses and donkeys) and one vector (Culicoides imicola) for African horse sickness in Spain is extended to consider vaccination strategies. If hosts were protected prior to virus introduction, elimination of simulated epidemics was related nonlinearly to the fraction protected. Protecting donkeys as well as horses increased the effectiveness of vaccination. Prevention of 50% of epidemics required 75% coverage of horses and donkeys or 90% coverage of horses only. Protection after the introduction of the virus was rarely successful in preventing outbreaks....
Use of Rhodococcus equi virulence-associated protein for immunization of foals against R equi pneumonia. To evaluate use of the virulence-associated protein of Rhodococcus equi in immunizing foals against R equi pneumonia. Methods: Eight (experimental group) and 6 (controls) mares with their foals. Methods: Virulence-associated protein extracted from R equi was used to prepare an acetone-precipitated. Triton X-extracted (APTX) antigen. After determination of the efficacy of passive immunization, in untreated foals or in foals given plasma from a horse vaccinated with APTX antigen or from a nonvaccinated horse, a field trial was done to evaluate the efficacy of vaccination of 8 mares, twice with A...
Clinical and laboratory alterations in horses during immunization with snake venoms for the production of polyvalent (Crotalinae) antivenom. Six horses were immunized with the venoms of Bothrops asper, Crotalus durissus durissus and Lachesis muta stenophrys for the production of polyvalent (Crotalinae) antivenom. During the immunization, clinical and laboratory alterations were evaluated in these animals, and the development of humoral immune response was followed. Only moderate local tissue changes (edema, abscesses, fistules and fibrosis) were observed in these animals, whereas no systemic alterations occurred. Regarding laboratory tests, there was a drop in hemoglobin concentration and hematocrit, together with an increment in t...
Use of a virulence-associated protein based enzyme-linked immunosorbent assay for Rhodococcus equi serology in horses. An enzyme-linked immunosorbent assay (ELISA) was developed against Rhodococcus equi using Triton X-114 detergent extracted whole cell material, in which the virulence associated protein (VapA) predominated. Enzymelinked immunosorbent assay titres corresponded to antibody reacting with VapA on Western blots. There was considerable variation in antibody titres of nonimmunised mares and in the time when the colostrally derived antibody of their foals had declined to low or undetectable titres. In general, antibodies in foals declined to their lowest levels at age 4-8 weeks. Seroconversion occurre...
Recombinant baculovirus-synthesized African horsesickness virus (AHSV) outer-capsid protein VP2 provides protection against virulent AHSV challenge. African horsesickness virus serotype 4 (AHSV-4) outer-capsid proteins VP2 or VP2 and VP5, prepared from single or dual recombinant baculovirus expression vectors grown in Sf9 insect cells, were administered in different amounts to horses and the neutralizing antibody responses were measured. Control and vaccinated horses were challenged with virulent AHSV-4 6 months later and monitored post challenge. The results indicated that two inoculations of extracts containing VP2 and VP5, or VP2 alone, in doses of 5 micrograms VP2 or more per horse, were sufficient to elicit protection against African ...
Suppression of testicular function using two dose rates of a reversible water soluble gonadotrophin releasing hormone (GnRH) vaccine in colts. To investigate the effect of two dose rates (200 and 400 ng) of a gonadotrophin releasing hormone (GnRH) vaccine on testicular function. Methods: A vaccination dose rate experiment. Methods: Two injections were administered 4 weeks apart to six colts in each treatment group. To maintain immunosuppression until the end of the breeding season, a third injection was given if antibody titres fell below 1000. Results: Effective antibody titres were present for 12 to 27 weeks. Testosterone concentrations decreased from 2.22 to 0.31 nmol/L 6 weeks after primary vaccination. Androstenedione concentrat...
Heterologous antisera and antivenins are essential biologicals: perspectives on a worldwide crisis. Active immunization against infectious disease is important. However, much of our world faces poverty, social injustice, and warfare, all of which cause universal immunization to remain a distant dream. Agents that provide passive immunity thus remain essential biologicals. The most important of these are human or equine antisera against rabies, tetanus, diphtheria, and snake antivenins. Homologous products are either unavailable or unaffordable in places where they are needed the most. Less expensive heterologous (equine) antisera can be purified and are safe to use, but these antisera are al...
Equine herpesvirus type 2 (EHV-2) as a predisposing factor for Rhodococcus equi pneumonia in foals: prevention of the bifactorial disease with EHV-2 immunostimulating complexes. Equine herpesvirus type 2 (EHV-2), a member of the Gammaherpesvirinae subfamily, was studied in a two-phase respiratory disease complex of young foals as a predisposing factor for the secondary bacterial invasion of lungs with Rhodococcus equi (R. equi). Foals were immunized against EHV-2 on a farm where R. equi pneumonia regularly occurred during the last years. The immunizations were performed by using a subunit vaccine which selectively presents envelope glycoproteins of EHV-2 in a multimeric form of immunostimulating complexes (iscoms). The etiological role of EHV-2 was estimated by observ...
Immunization with VP2 is sufficient for protection against lethal challenge with African horsesickness virus Type 4. Horses were immunized by inoculation with a vaccinia construct containing a full-length cDNA corresponding to the L2 gene segment of African horsesickness virus type 4(AHSV-4). All immunized horses developed serum neutralizing antibodies prior to challenge with virulent AHSV-4. No ELISA-reactive antibodies were present prior to challenge. A group of four seronegative control horses died after developing clinical signs and lesions typical of the pulmonary form of African horsesickness while the immunized horses were clinically normal. Increases in serum neutralizing and ELISA-reactive antibody ...
Full protection against African horsesickness (AHS) in horses induced by baculovirus-derived AHS virus serotype 4 VP2, VP5 and VP7. African horsesickness virus serotype 4 (AHSV-4) outer capsid protein VP2, or VP2 and VP5 plus inner capsid protein VP7, derived from single or dual recombinant baculovirus expression vectors were used in different combinations to immunize horses. When the proteins were purified by affinity chromatography, the combination of all three proteins induced low levels of neutralizing antibodies and conferred protection against virulent virus challenge. However, purified VP2 or VP2 and VP5 in the absence of VP7 failed to induce neutralizing antibodies and protection. Immunization with non-purified pro...
Effect of vaccination of ponies with A4 anti-idiotypic antibody on serum idiotype (1C9) and antilipid A concentration. To evaluate the humoral response of horses to vaccination, using a murine monoclonal anti-idiotypic antibody (A4) that shares an epitope with lipid A. Methods: Serum concentrations of antilipid A antibody and 1C9 (epitope on murine monoclonal antilipid A antibody) were measured serially during the period of vaccination with A4. Methods: 6 clinically normal adult ponies. Methods: Ponies were inoculated IM 3 times at monthly intervals with A4. Two weeks after each inoculation, serum was obtained and was assayed by ELISA for antilipid A and 1C9 concentrations. Additional vaccinations were given t...
An assessment of mucosal immunisation in protection against Streptococcus equi (‘Strangles’) infections in horses. 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...
Characteristics of equine herpesvirus 1 glycoproteins expressed in insect cells. 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...
Equine arteritis virus-neutralizing antibody in the horse is induced by a determinant on the large envelope glycoprotein GL. 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...