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.
Wimer CL, Schnabel CL, Perkins G, Babasyan S, Freer H, Stout AE, Rollins A, Osterrieder N, Goodman LB, Glaser A, Wagner B.The equine herpesvirus type 1 (EHV-1) ORF1 and ORF71 genes have immune modulatory effects in vitro. Experimental infection of horses using virus mutants with multiple deletions including ORF1 and ORF71 showed promise as vaccine candidates against EHV-1. Here, the combined effects of ORF1 and ORF71 deletions from the neuropathogenic EHV-1 strain Ab4 on clinical disease and host immune response were further explored. Three groups of EHV-1 naïve horses were experimentally infected with the ORF1/71 gene deletion mutant (Ab4ΔORF1/71), the parent Ab4 strain, or remained uninfected. In comparison t...
Hellman S, Hjertner B, Morein B, Fossum C.The immunomodulatory effect of a new particulate adjuvant, G3, alone or in combination with agonists to TLR2/1 or TLR5 was evaluated in cultures of equine PBMC. Exposure to the G3 adjuvant up-regulated genes encoding IFN-γ, IL-1β, IL-6, IL-8, IL-12p40 and IL-23p19 in the majority of the horses tested, indicating that the G3 adjuvant induced a pro-inflammatory and Th1 dominated profile. In accordance, genes encoding IL-13, IL-4, IL-10 and TGF-β remained unaffected and genes encoding IFN-α, IL-17A and TNF-α were only occasionally and weakly induced. The two TLR agonists Pam3CSK4 (TLR2/1) an...
Dennis SJ, O'Kennedy MM, Rutkowska D, Tsekoa T, Lourens CW, Hitzeroth II, Meyers AE, Rybicki EP.African horse sickness (AHS) is caused by multiple serotypes of the dsRNA AHSV and is a major scourge of domestic equids in Africa. While there are well established commercial live attenuated vaccines produced in South Africa, risks associated with these have encouraged attempts to develop new and safer recombinant vaccines. Previously, we reported on the immunogenicity of a plant-produced AHS serotype 5 virus-like particle (VLP) vaccine, which stimulated high titres of AHS serotype 5-specific neutralizing antibodies in guinea pigs. Here, we report a similar response to the vaccine in horses. ...
Aksular M, Calvo-Pinilla E, Marín-López A, Ortego J, Chambers AC, King LA, Castillo-Olivares J.African horse sickness is a severe, often fatal, arboviral disease of equids. The control of African horse sickness virus (AHSV) in endemic countries is based currently on the use of live attenuated vaccines despite some biosafety concerns derived from its biological properties. Thus, experimental vaccination platforms have been developed over the years in order to avoid the biosafety concerns associated with the use of attenuated vaccines. Various studies showed that baculovirus-expressed AHSV-VP2 or modified Vaccinia Ankara virus expressing AHSV-VP2 (MVA-VP2) induced virus neutralising antib...
Satyam R, Janahi EM, Bhardwaj T, Somvanshi P, Haque S, Najm MZ.Usutu Virus (USUV; flavivirus) is a re-emerging pathogen invading the territories of European countries, Asia, and Africa. It is a mosquito-borne zoonotic virus with a bi-directional transmission route from animal to human and vice versa, and causes neurological disorders such as meningoencephalitis in bats, Homo sapiens, birds and horses. Due to limited availability of information about USUV and its deleterious effects on neural cells causing neurologic impairments, it becomes imperative to study this virus in detail to equip ourselves with a solution beforehand. The current study aims to ide...
Abhishek , Kumar B, Anjay , Mishra AK, Prakash C, Priyadarshini A, Rawat M.Salmonella Abortusequi causes important clinical diseases in horses possibly leading to abortion. In the present investigation, the protective efficacy of both plain and aluminum hydroxide gel adjuvanted phage lysate was evaluated in guinea pig model. Broad host range bacteriophage P-SAE-2, was characterized and used for generation of lysates. Three different lysate batches, produced through separate cycles and characterized, were pooled together for immunization study. Plain and adjuvanted phage lysate preparations elicited both humoral and cellmediated immunity. The adjuvanted lysate at a do...
Ata EB, Zaghawa A, Ghazy AA, Elsify A, Abdelrahman K, Kasem S, Nayel M.Equine herpesvirus-1 (EHV-1) is an important pathogen, which infects horses worldwide with high morbidity but low mortality rates. The respiratory disorders and abortions are the most common indicators. Ab4p (an abortigenic and paralytic virus) is one of the most important and virulent strains. The development and functional characterization of the open reading frame-68 (ORF68) negative EHV-1 Ab4p mutants and an assessment of their roles in the infection at the cellular level were the main targets of the current study. Escherichia coli DH10β containing the Ab4p bacterial artificial chromosome...
Bechert U, Rohde J, Freer H, Wagner B.SpayVac is an immunocontraceptive vaccine based on porcine zona pellucida (pZP) antigens and uses a patented liposome formulation (VacciMax or DepoVax). It has delivered single-dose, long-lasting (4-10 years) immunocontraception in several species. Previous studies have demonstrated a positive correlation between levels of pZP antibodies produced and contraceptive effect; however, individual mares that were consistently infertile did not necessarily have the highest antibody titers. The objective of this study was to identify potential differences in specific immunoglobulin G (IgG) isotype res...
Nolan MB, Bertschinger HJ, Roth R, Crampton M, Martins IS, Fosgate GT, Stout TA, Schulman ML.An important determinant in the selection of any contraceptive agent is the impact on ovarian function, both in the short and longer term. In this study, ovarian activity was monitored in mares immunised with one of the following vaccine formulations; native porcine zona pellucida (pZP), recombinant zona pellucida proteins ZP3 and ZP4 (reZP), pZP and reZP combined or a commercially available anti-GnRH vaccine. The ZP antigens were prepared in an adjuvant formulation consisting of 6% polymeric adjuvant (Montanide™ PetGel A, Seppic, France) and 500 μg polyinosinic-polycytidylic acid - TLR3-...
Carossino M, Barrandeguy ME, Li Y, Parreño V, Janes J, Loynachan AT, Balasuriya UBR.Equine rotavirus A (ERVA) is the leading cause of diarrhea in neonatal foals and a major health problem to the equine breeding industry worldwide. The G3P[12] and G14P[12] ERVA genotypes are the most prevalent in foals with diarrhea. Control and prevention strategies include vaccination of pregnant mares with an inactivated vaccine containing a prototype ERVA G3P[12] strain with limited and controversial field efficacy. Here, we performed the molecular characterization of ERVA strains circulating in central Kentucky using fecal samples collected during the 2017 foaling season. The data indicat...
Jonsdottir S, Stefansdottir SB, Kristinarson SB, Svansson V, Bjornsson JM, Runarsdottir A, Wagner B, Marti E, Torsteinsdottir S.Insect bite hypersensitivity is an allergic dermatitis of horses caused by bites of Culicoides midges. Sufficient amount of pure, endotoxin-free allergens is a prerequisite for development and monitoring of preventive and therapeutic allergen immunotherapy. Aims of the study were to compare the Culicoides nubeculosus (Cul n) allergens Cul n 3 and Cul n 4, produced in transgenic barley grains with the corresponding E. coli or insect cells expressed proteins for measuring antibody and cytokine responses. Allergen-specific IgG responses were measured by ELISA in sera from twelve horses not expose...
van Rijn PA, Maris-Veldhuis MA, Boonstra J, van Gennip RGP.African Horse Sickness Virus (AHSV) (Orbivirus genus, Reoviridae family) causes high mortality in naïve domestic horses with enormous economic and socio-emotional impact. There are nine AHSV serotypes showing limited cross neutralization. AHSV is transmitted by competent species of Culicoides biting midges. AHS is a serious threat beyond the African continent as endemic Culicoides species in moderate climates transmit the closely related prototype bluetongue virus. There is a desperate need for safe and efficacious vaccines, while DIVA (Differentiating Infected from Vaccinated) vaccines would...
Tan R, Hodge A, Klein R, Edwards N, Huang JA, Middleton D, Watts SP.To determine the antibody responses to a commercial Hendra virus vaccine (Equivac® HeV) in a field environment. Methods: A group of 61 horses received a primary vaccination course comprising two doses administered 3-6 weeks apart (V1, V2) and a 3rd dose (V3) given 6 months after the second. This was followed by booster vaccinations at 12 monthly intervals (V4, V5). Antibody titres were assessed using a virus-neutralisation test. Results: Neutralising antibodies against HeV were not detected prior to vaccination. Antibodies were detected in 54/57 horses at 3 weeks after V1 and 51/51 had ...
Ghosh M, Sharma N, Singh AK, Gera M, Pulicherla KK, Jeong DK.For more than a quarter of a century, sequencing technologies from Sanger's method to next-generation high-throughput techniques have provided fascinating opportunities in the life sciences. The continuing upward trajectory of sequencing technologies will improve livestock research and expedite the development of various new genomic and technological studies with farm animals. The use of high-throughput technologies in livestock research has increased interest in metagenomics, epigenetics, genome-wide association studies, and identification of single nucleotide polymorphisms and copy number va...
Fettelschoss-Gabriel A, Fettelschoss V, Thoms F, Giese C, Daniel M, Olomski F, Kamarachev J, Birkmann K, Bühler M, Kummer M, Zeltins A, Marti E....Insect-bite hypersensitivity is the most common allergic dermatitis in horses. Excoriated skin lesions are typical symptoms of this seasonal and refractory chronic disease. On a cellular level, the skin lesions are characterized by massive eosinophil infiltration caused by an underlying allergic response. To target these cells and treat disease, we developed a therapeutic vaccine against equine IL-5 (eIL-5), the master regulator of eosinophils. The vaccine consisted of eIL-5 covalently linked to a virus-like particle derived from cucumber mosaic virus containing the tetanus toxoid universal T-...
Ahlers LRH, Goodman AG.Vector-borne diseases, including arboviruses, pose a serious threat to public health worldwide. Arboviruses of the flavivirus genus, such as Zika virus (ZIKV), dengue virus, yellow fever virus (YFV), and West Nile virus (WNV), are transmitted to humans from insect vectors and can cause serious disease. In 2017, over 2,000 reported cases of WNV virus infection occurred in the United States, with two-thirds of cases classified as neuroinvasive. WNV transmission cycles through two different animal populations: birds and mosquitoes. Mammals, particularly humans and horses, can become infected thro...
Wang XF, Liu Q, Wang YH, Wang S, Chen J, Lin YZ, Ma J, Zhou JH, Wang X.The equine infectious anemia virus (EIAV) attenuated vaccine was developed by long-term passaging of a field-isolated virulent strain in cross-species hosts, followed by successive cultivation in cells To explore the molecular mechanism underlying the evolution of the EIAV attenuated vaccine, a systematic study focusing on long-terminal-repeat (LTR) variation in numerous virus strains ranging from virulent EIAV to attenuated EIAV was performed over time both and Two hypervariable regions were identified within the U3 region in the enhancer region (EHR) and the negative regulatory element (N...
Waller A., head of bacteriology at the AHT, describes the causative agent of strangles in horses, and discusses progress with the latest research aimed at improving vaccines against this global disease.
van Rijn PA, Maris-Veldhuis MA, Potgieter CA, van Gennip RGP.African horse sickness virus (AHSV) is a virus species in the genus Orbivirus of the family Reoviridae. Currently, nine serotypes have been defined showing limited cross neutralization. AHSV is transmitted by species of Culicoides biting midges and causes African Horse Sickness (AHS) in equids with a mortality up to 95% in naïve domestic horses. AHS has become a serious threat for countries outside Africa, since endemic Culicoides species in moderate climates are competent vectors of closely related bluetongue virus. AHS outbreaks cause huge economic losses in developing countries. In the dev...
van Dorland HA, Zanoni R, Gerber V, Jeannerat E, Wiederkehr D, Burger D.Bio-Strath is a plasmolyzed yeast product enriched with herbs, malt, honey and orange juice. In this study, the effect of Equi-Strath , the adapted product for horses, on the equine immune system was evaluated. A routine influenza booster vaccination was used as a model to study the effects of Equi-Strath supplementation on the immune response. Twenty healthy Franches-Montagnes stallions with pre-existing antibody levels were randomly divided into a study group (SG, n = 10) receiving 0.06 mL/kg bodyweight of Equi-Strath , and a control group (CG, n = 10), receiving the same amount of plac...
Ibañez LI, Caldevilla CA, Paredes Rojas Y, Mattion N.H3N8 influenza virus strains have been associated with infectious disease in equine populations throughout the world. Although current vaccines for equine influenza stimulate a protective humoral immune response against the surface glycoproteins, disease in vaccinated horses has been frequently reported, probably due to poor induction of cross-reactive antibodies against non-matching strains. This work describes the performance of a recombinant protein vaccine expressed in prokaryotic cells (ΔHAp) and of a genetic vaccine (ΔHAe), both based on the conserved stem region of influenza hemagglut...
Bryant NA, Wilkie GS, Russell CA, Compston L, Grafham D, Clissold L, McLay K, Medcalf L, Newton R, Davison AJ, Elton DM.Equine herpesvirus 1 (EHV-1) causes respiratory disease, abortion, neonatal death and neurological disease in equines and is endemic in most countries. The viral factors that influence EHV-1 disease severity are poorly understood, and this has hampered vaccine development. However, the N752D substitution in the viral DNA polymerase catalytic subunit has been shown statistically to be associated with neurological disease. This has given rise to the term "neuropathic strain," even though strains lacking the polymorphism have been recovered from cases of neurological disease. To broaden understan...
Boyle AG, Timoney JF, Newton JR, Hines MT, Waller AS, Buchanan BR.This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the impo...
Robinson C, Frykberg L, Flock M, Guss B, Waller AS, Flock JI.The host-restricted pathogen Streptococcus equi causes strangles in the horse, which is characterised by abscessation of the lymph nodes of the head and neck. The disease is endemic throughout the world causing considerable welfare and economic cost to the horse industry. Here we report the results of three studies where ponies were vaccinated with combinations of recombinant fusion proteins to optimise vaccine production and the level of protection conferred. Optimal protection was conferred by a prototype multicomponent subunit vaccine, Strangvac 4, which contained eight proteins CNE, SclC, ...
Rodriguez L, Reedy S, Nogales A, Murcia PR, Chambers TM, Martinez-Sobrido L.H3N8 equine influenza virus (EIV) is an important and significant respiratory pathogen of horses. EIV is enzootic in Europe and North America, mainly due to the suboptimal efficacy of current vaccines. We describe, for the first time, the generation of a temperature sensitive (ts) H3N8 EIV live-attenuated influenza vaccine (LAIV) using reverse-genetics approaches. Our EIV LAIV was attenuated (att) in vivo and able to induce, upon a single intranasal administration, protection against H3N8 EIV wild-type (WT) challenge in both a mouse model and the natural host, the horse. Notably, since our EIV...
Yamanaka T, Nemoto M, Bannai H, Tsujimura K, Matsumura T, Kokado H, Gildea S, Cullinane A.Equine influenza (EI) vaccine has been widely used. However, the causative EI virus (H3N8) undergoes continuous antigenic drift, and the vaccine strains must be periodically reviewed and if necessary, updated to maintain vaccine efficacy against circulating viruses. In 2016, the Japanese vaccine was updated by replacing the old viruses with the Florida sub-lineage Clade (Fc) 2 virus, A/equine/Yokohama/aq13/2010 (Y10). We investigated the virus neutralization (VN) antibody response to Fc2 viruses currently circulating in Europe, after booster or primary immunization with the new vaccine. These ...
Gershwin LJ.Vaccines are important for providing protection from infectious diseases. Vaccination initiates a process that stimulates development of a robust and long-lived immune response to the disease agents in the vaccine. Side effects are sometimes associated with vaccination. These vary from development of acute hypersensitivity responses to vaccine components to local tissue reactions that are annoying but not significantly detrimental to the patient. The pathogenesis of these responses and the consequent clinical outcomes are discussed. Overstimulation of the immune response and the potential rela...
Woodward A, Rash AS, Medcalf E, Bryant NA, Elton DM.Equine influenza is a major cause of respiratory infections in horses and causes widespread epidemics, despite the availability of commercial vaccines. Antigenic drift within the haemagglutinin (HA) glycoprotein is thought to play a part in vaccination breakdown. Here, we carried out a detailed investigation of the 1989 UK outbreak, using reverse genetics and site-directed mutagenesis, to determine the individual contribution of amino acid substitutions within HA. Mutations at positions 159, 189 and 227 all altered antigenicity, as measured by haemagglutination-inhibition assays. We also compa...
Tonkin DR, Whitmore A, Johnston RE, Barro M.Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-s...
Ault A, Zajac AM, Kong WP, Gorres JP, Royals M, Wei CJ, Bao S, Yang ZY, Reedy SE, Sturgill TL, Page AE, Donofrio-Newman J, Adams AA, Balasuriya UB....Equine influenza A (H3N8) virus infection is a leading cause of respiratory disease in horses, resulting in widespread morbidity and economic losses. As with influenza in other species, equine influenza strains continuously mutate, often requiring the development of new vaccines. Current inactivated (killed) vaccines, while efficacious, only offer limited protection against diverse subtypes and require frequent boosts. Research into new vaccine technologies, including gene-based vaccines, aims to increase the neutralization potency, breadth, and duration of protective immunity. Here, we demons...
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...
Nemoto M, Kanno T, Bannai H, Tsujimura K, Yamanaka T, Kokado H.A vaccine for equine coronavirus (ECoV) is so far unavailable. Bovine coronavirus (BCoV) is antigenically related to ECoV; it is therefore possible that BCoV vaccine will induce antibodies against ECoV in horses. This study investigated antibody response to ECoV in horses inoculated with BCoV vaccine. Virus neutralization tests showed that antibody titers against ECoV increased in all six horses tested at 14 days post inoculation, although the antibody titers were lower against ECoV than against BCoV. This study showed that BCoV vaccine provides horses with antibodies against ECoV to some exte...
Goodyear A, Troyer R, Bielefeldt-Ohmann H, Dow S.The Gram-negative bacterium Burkholderia mallei causes rapidly fatal illness in equines and humans when contracted by inhalation and also has the potential to be used as a bioweapon. However, little is known regarding the early innate immune responses and signaling mechanisms required to generate protection from pneumonic B. mallei infection. We showed previously that monocyte chemoattractant protein 1 (MCP-1) was a critical chemokine required for protection from pneumonic B. mallei infection. We have now extended those studies to identify key Toll-like receptor (TLR) signaling pathways, effec...
Teymournejad O, Lin M, Bekebrede H, Kamr A, Toribio RE, Arroyo LG, Baird JD, Rikihisa Y.Potomac horse fever (PHF), a severe and frequently fatal febrile diarrheal disease, has been known to be caused only by , an endosymbiont of digenean trematodes. Here, we report the cell culture isolation of a new species found in two locations in eastern Ontario, Canada, in 2016 and 2017 (in addition to 10 variable strains of ) from PCR-negative horses with clinical signs of PHF. Gene sequences of 16S rRNA and the major surface antigen P51 of this new species were distinct from those of all previously characterized strains and species, except for those from an uncharacterized species cu...
Walton TE, Alvarez O, Buckwalter RM, Johnson KM.Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 10(3.5) median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respe...
Dennis SJ, O'Kennedy MM, Rutkowska D, Tsekoa T, Lourens CW, Hitzeroth II, Meyers AE, Rybicki EP.African horse sickness (AHS) is caused by multiple serotypes of the dsRNA AHSV and is a major scourge of domestic equids in Africa. While there are well established commercial live attenuated vaccines produced in South Africa, risks associated with these have encouraged attempts to develop new and safer recombinant vaccines. Previously, we reported on the immunogenicity of a plant-produced AHS serotype 5 virus-like particle (VLP) vaccine, which stimulated high titres of AHS serotype 5-specific neutralizing antibodies in guinea pigs. Here, we report a similar response to the vaccine in horses. ...
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...
Cauchard J, Sevin C, Ballet JJ, Taouji S.The aim of this study was to evaluate serum IgG antibody levels and opsonizing activity in foals from pregnant mares immunized with either proteins from an R. equi strain containing virulence-associated protein A (VapA), an immunodominant surface-expressed lipoprotein encoded by a virulence plasmid crucial for virulence in foals, or a whole killed virulent R. equi preparation. Forty-eight pregnant mares were distributed into three groups, i.e. 24 immunized with R. equi VapA protein antigen associated with a water-based nanoparticle adjuvant (Montanide IMS 3012), 8 immunized with whole killed R...
Heldens JG, Pouwels HG, Derks CG, Van de Zande SM, Hoeijmakers MJ.Equine influenza is a contagious disease caused by equine influenza virus which belongs to the orthomyxovirus family. Outbreaks of equine influenza cause severe economic loses to the horse industry and consequently horses in competition are required to be regularly vaccinated against equine influenza. Unlike the existing inactivated vaccines, Equilis Prequenza Te is the only one able to induce protection against clinical disease and virus excretion after a primary vaccination course consisting of two vaccine applications 4-6 weeks apart until the recommended time of the third vaccination. In t...
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...
Ma J, Shi N, Jiang CG, Lin YZ, Wang XF, Wang S, Lv XL, Zhao LP, Shao YM, Kong XG, Zhou JH, Shen RX.To investigate essential factors that determine the efficacy of vaccines against lentiviruses, an effective attenuated equine infectious anemia virus (EIAV) vaccine strain and a proviral derivative of the vaccine were compared with respect to differences in inducing protective immunity. Although these two strains replicated equally well in vitro and in vivo, the proviral strain induced significantly less protection from disease and infection caused by viral challenge and significantly lower specific neutralizing capability. These findings indicated that the proviral strain had lost the ability...
El Garch H, Crafford JE, Amouyal P, Durand PY, Edlund Toulemonde C, Lemaitre L, Cozette V, Guthrie A, Minke JM.A recombinant canarypox virus vectored vaccine co-expressing synthetic genes encoding outer capsid proteins, VP2 and VP5, of African horse sickness virus (AHSV) serotype 4 (ALVAC(®)-AHSV4) has been demonstrated to fully protect horses against homologous challenge with virulent field virus. Guthrie et al. (2009) detected weak and variable titres of neutralizing antibody (ranging from <10 to 40) 8 weeks after vaccination leading us to hypothesize that there could be a participation of cell mediated immunity (CMI) in protection against AHSV4. The present study aimed at characterizing the CMI ind...
Daly JM, Yates RJ, Browse G, Swann Z, Newton JR, Jessett D, Davis-Poynter N, Mumford JA.Vaccination and challenge studies in ponies are the most relevant experimental system for predicting whether strains included in equine influenza vaccines are relevant, but they are difficult to perform. Objective: In order to investigate the feasibility of using a small animal model, results of a cross-protection study in hamsters were compared with those from a previous pony challenge experiment. Methods: Animals were immunised with inactivated vaccines containing one of 4 strains of equine influenza A H3N8 subtype virus isolated over a 26 year period (1963 to 1989), then challenged with a 1...
Rappocciolo G, Birch J, Ellis SA.There is good evidence that cytotoxic T lymphocytes play an important role in the clearance of equine herpesvirus-1 (EHV1) in horses. We have demonstrated that, in common with other alphaherpesviruses, EHV1 infection can lead to dramatic down-regulation of MHC class I expression at the cell surface, a common strategy for pathogen evasion of the host immune response. This down-regulation is specific for MHC class I and does not reflect a general shut-off of host-cell protein synthesis. The use of monoclonal antibodies that recognize different MHC class I epitopes has demonstrated that the effec...
Vandekerckhove A, Glorieux S, Broeck WV, Gryspeerdt A, van der Meulen KM, Nauwynck HJ.An in vitro model of the upper respiratory tract of the horse was developed to investigate mechanisms of respiratory diseases. Four tissues of the upper respiratory tract of three horses were collected. Explants were maintained in culture at an air-liquid interface for 96h. At 0, 24, 48, 72 and 96h of cultivation, a morphometric analysis was performed using light microscopy, scanning electron microscopy and transmission electron microscopy. The explants were judged on morphometric changes of epithelium, basement membrane and connective tissue. Viability was evaluated using a fluorescent Termin...
Gildea S, Arkins S, Walsh C, Cullinane A.Protection against equine influenza virus (EIV) relies largely on the production of circulating antibodies specific for the haemagglutinin (HA) glycoprotein. The objective of this study was to determine the antibody response of National Hunt horses in training to booster vaccination. The antibody response to the six equine influenza vaccines available in Ireland (three whole inactivated vaccines, two subunit vaccines and a canary pox recombinant vaccine), was monitored by single radial haemolysis (SRH) for six months post vaccination. There was no significant difference between antibody respon...
Rocha JN, Cohen ND, Bordin AI, Brake CN, Giguère S, Coleman MC, Alaniz RC, Lawhon SD, Mwangi W, Pillai SD.There is currently no licensed vaccine that protects foals against Rhodococcus equi-induced pneumonia. Oral administration of live, virulent R. equi to neonatal foals has been demonstrated to protect against subsequent intrabronchial challenge with virulent R. equi. Electron beam (eBeam)-inactivated R. equi are structurally intact and have been demonstrated to be immunogenic when administered orally to neonatal foals. Thus, we investigated whether eBeam inactivated R. equi could protect foals against developing pneumonia after experimental infection with live, virulent R. equi. Foals (n = 8) w...
Ma H, Lundy JD, Cottle EL, O'Malley KJ, Trichel AM, Klimstra WB, Hartman AL, Reed DS, Teichert T.Alphaviruses such as Venezuelan equine encephalitis virus (VEEV) and Eastern equine encephalitis virus (EEEV) are arboviruses that can cause severe zoonotic disease in humans. Both VEEV and EEEV are highly infectious when aerosolized and can be used as biological weapons. Vaccines and therapeutics are urgently needed, but efficacy determination requires animal models. The cynomolgus macaque (Macaca fascicularis) provides a relevant model of human disease, but questions remain whether vaccines or therapeutics can mitigate CNS infection or disease in this model. The documentation of alphavirus e...
Netolitzky DJ, Schmaltz FL, Parker MD, Rayner GA, Fisher GR, Trent DW, Bader DE, Nagata LP.The complete nucleotide sequence of the 71V-1658 strain of western equine encephalitis virus (WEE) was determined (minus 25 nucleotides from the 5' end). A 5' RACE reaction was used to sequence the 5' terminus from WEE strain CBA87. The deduced WEE genome was 11508 nucleotides in length, excluding the 5' cap nucleotide and 3' poly(A) tail. The nucleotide composition was 28% A, 25% C, 25% G and 22% U. Comparison with partial WEE sequences of strain 5614 (nsP2-nsP3 of the nonstructural region) and strain BFS1703 (26S structural region) revealed comparatively little variation; a total of 149 nucl...
Wang X, Wang S, Lin Y, Jiang C, Ma J, Zhao L, Lv X, Wang F, Shen R, Kong X, Zhou J.A lentiviral vaccine, live attenuated equine infectious anemia virus (EIAV) vaccine, was developed in the 1970s, and this has made tremendous contributions to the control of equine infectious anemia (EIA) in China. Four key virus strains were generated during the attenuation of the EIAV vaccine: the original Liao-Ning strain (EIAV(LN40)), a donkey-adapted virulent strain (EIAV(DV117)), a donkey-leukocyte-attenuated vaccine strain (EIAV(DLV121)), and a fetal donkey dermal cell (FDD)-adapted vaccine strain (EIAV(FDDV13)). In this study, we analyzed the proviral genomes of these four EIAV strains...
Tomlinson JE, Wolfisberg R, Fahnøe U, Patel RS, Trivedi S, Kumar A, Sharma H, Nielsen L, McDonough SP, Bukh J, Tennant BC, Kapoor A, Rosenberg BR....Equine hepacivirus (EqHV) is phylogenetically the closest relative of HCV and shares genome organization, hepatotropism, transient or persistent infection outcome, and the ability to cause hepatitis. Thus, EqHV studies are important to understand equine liver disease and further as an outbred surrogate animal model for HCV pathogenesis and protective immune responses. Here, we aimed to characterize the course of EqHV infection and associated protective immune responses. Seven horses were experimentally inoculated with EqHV, monitored for 6 months, and rechallenged with the same and, subsequen...
Diaz-San Segundo F, Dias CC, Moraes MP, Weiss M, Perez-Martin E, Owens G, Custer M, Kamrud K, de los Santos T, Grubman MJ.We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach ...
Munday JS, Knight CG, Luff JA.Papillomaviruses (PVs) are well recognized to cause pre-neoplastic and neoplastic diseases in humans. Similarly, there is increasing evidence that PVs play a significant role in the development of pre-neoplastic and neoplastic diseases of the haired skin of dogs and cats, and the mucosa of horses. As the mechanisms by which PVs cause neoplasia are well studied in humans, it is valuable to compare the PV-induced neoplasms of humans with similar PV-associated neoplasms in the companion animal species. In the second part of this comparative review, the pre-neoplastic and neoplastic diseases thoug...
Bordin AI, Pillai SD, Brake C, Bagley KB, Bourquin JR, Coleman M, Oliveira FN, Mwangi W, McMurray DN, Love CC, Felippe MJ, Cohen ND.Rhodococcus equi is an important pathogen of foals that causes severe pneumonia. To date, there is no licensed vaccine effective against R. equi pneumonia of foals. The objectives of our study were to develop an electron beam (eBeam) inactivated vaccine against R. equi and evaluate its immunogenicity. A dose of eBeam irradiation that inactivated replication of R. equi while maintaining outer cell wall integrity was identified. Enteral administration of eBeam inactivated R. equi increased interferon-γ production by peripheral blood mononuclear cells in response to stimulation with virulent R. ...
Figueiredo LF, Dias-Lopes C, Alvarenga LM, Mendes TM, Machado-de-Ávila RA, McCormack J, Minozzo JC, Kalapothakis E, Chávez-Olórtegui C.A chimeric protein (rCpLi) was constructed expressing three epitopes of rLiD1, a dermonecrotic toxin from the venom of Loxosceles intermedia spider. We have analyzed the neutralization potential of sera obtained by immunization of horses with rCpLi and rCpLi combined with initial doses of venoms and compared these with antivenom traditionally produced in horses using crude Loxosceles gaucho, Loxosceles laeta and L. intermedia venoms as antigens. We have demonstrated by ELISA that horses immunized with three initial doses of crude venom containing mixtures of L. intermedia, L. gaucho and L. lae...
Bryant NA, Paillot R, Rash AS, Medcalf E, Montesso F, Ross J, Watson J, Jeggo M, Lewis NS, Newton JR, Elton DM.During 2007, large outbreaks of equine influenza (EI) caused by Florida sublineage Clade 1 viruses affected horse populations in Japan and Australia. The likely protection that would be provided by two modern vaccines commercially available in the European Union (an ISCOM-based and a canarypox-based vaccine) at the time of the outbreaks was determined. Vaccinated ponies were challenged with a representative outbreak isolate (A/eq/Sydney/2888-8/07) and levels of protection were compared.A group of ponies infected 18 months previously with a phylogenetically-related isolate from 2003 (A/eq/South...
