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.
Science (New York, N.Y.)August 25, 1961
Volume 134, Issue 3478 565-566 doi: 10.1126/science.134.3478.565
LOWENTHAL JP, BERMAN S, GROGAN EW.Protection tests in guinea pigs indicate that vaccines prepared from virus propagated in chick embryo cell cultures are as effective as the purified whole chick embryo vaccines which are currently used for human immunization against eastern equine encephalomyelitis.
HETRICK FM, YANCEY FS, HANSEN PA, BYRNE RJ. Four horses inoculated with EEE virus remained asymptomatic following injection but did develop measurable HI and neutralizing antibodies as a result of infection. HI antibodies were detectable earlier than neutralizing antibodies but the levels tended to drop more rapidly. 2. Of 14 horses and ponies having significant levels of neutralizing antibody, 5 to 9 had measurable HI antibody depending on number of units of antigen employed in the test. 3. Sera from 3 clinical cases of EEE were positive on the HI test while only one of these animals had a significant neutralizing antibody level.
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...
Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize cur...
Nichani AK, Sharma RD, Sarup S.Efficacy of medium RPMI-1640 (supplied by Gibco USA, Centron and Hi-media) supplemented with horse, donkey, sheep and goat sera was evaluated for in vitro propagation of Theileria annulata (Hisar) infected bovine mononuclear cells. The results were compared with the growth rate in RPMI-1640 supplemented with foetal bovine serum (Gibco). RPMI-1640 (Gibco) proved to be the best medium for in vitro cultivation of the parasite infected cells. Foetal bovine serum could be easily, safely and reliably substituted with goat and sheep sera in the growth medium. Horse and donkey sera also gave comparabl...
Cohen ND, Hughes EV, Bayne C, Morris ERA, Bray JM, Landrock KK, Gonzales DM, Baker RM, Klein RL, Liu W, Legere RM, Wehmeyer SG, Bordin AI....Evaluate the immunogenicity of a vaccine targeting the S protein (Ssee) of Streptococcus equi subsp equi and determine antibody activity against Ssee in horses with strangles. Methods: The study was designed as a prospective experiment using 20 university-owned Quarter Horses and a cross-sectional serosurvey of 78 privately owned horses with strangles. Horses were immunized IM with 0 (n = 4), 200 (n = 8), or 400 (n = 8) μg of recombinant Ssee at weeks 0, 4, and 12. Serum and nasal secretions were collected at weeks 0, 4, 6, 12, 16, and 28 and tested by ELISA for immunoglobulin (Ig)-G against ...
Cohen ND, Hughes EV, Bayne C, Morris ERA, Bray JM, Landrock KK, Gonzales DM, Baker RM, Klein RL, Liu W, Legere RM, Wehmeyer SG, Bordin AI....Evaluate the immunogenicity of a vaccine targeting the S protein (Ssee) of Streptococcus equi subsp equi and determine antibody activity against Ssee in horses with strangles. Methods: The study was designed as a prospective experiment using 20 university-owned Quarter Horses and a cross-sectional serosurvey of 78 privately owned horses with strangles. Horses were immunized IM with 0 (n = 4), 200 (n = 8), or 400 (n = 8) μg of recombinant Ssee at weeks 0, 4, and 12. Serum and nasal secretions were collected at weeks 0, 4, 6, 12, 16, and 28 and tested by ELISA for immunoglobulin (Ig)-G against ...
Jacob O, Hause B, Peters-Smith K, Adam EN, Page AE, Floyd C, Tucker C, Eertink LG, Wang D, Li F.Equine sarcoids are the most identified skin tumors of horses, which are highly associated with bovine papillomavirus infection. Sarcoids can impair the use of the horse and are difficult to treat, resulting in significant economic losses and a welfare concern. There is no vaccine available to protect global equines from sarcoids. We aimed to determine the safety and protective antibody response in horses immunized with a recombinant baculovirus vector vaccine expressing the L1 protein of bovine papillomavirus type 1 (BPV1). A group of 10 clinically healthy, sarcoid-free horses were immunized ...
O'Kennedy MM, Reedy SE, Abolnik C, Khan A, Smith T, du Preez I, Olajide E, Daly J, Cullinane A, Chambers TM.Equine influenza (EI) is a highly contagious acute respiratory disease of wild and domesticated horses, donkeys, mules, and other Equidae. EI is caused by the Equine Influenza virus (EIV), is endemic in many countries and outbreaks still have a severe impact on the equine industry globally. Conventional EI vaccines are widely used, but a need exists for a platform that facilitates prompt manufacturing of a highly immunogenic, antigenically matched, updated vaccine product. Here we developed a plant-produced bivalent EI virus-like particle (VLP) vaccine candidate which lacks the viral genome an...
McNabb L, McMahon A, Woube EG, Agnihotri K, Colling A, Broder CC, Kucinskaite-Kodze I, Petraityte-Burneikiene R, Bowden TR, Halpin K.Hendra virus (HeV) is a bat-borne zoonotic agent which can cause a severe and highly fatal disease and can be transferred from animals to humans. It has caused over 100 deaths in horses since it was discovered in 1994. Four out of seven infected humans have died. Since the release of the HeV vaccine (Equivac® HeV Hendra Virus Vaccine for Horses, Zoetis Australia Pty Ltd., Rhodes, NSW 2138) in Australia, there has been an urgent requirement for a serological test for differentiating infected from vaccinated animals (DIVA). All first-line diagnostic serological assays at the Australian Centre f...
Gao X, Liu J, Xu K, Hu J, Xiao C, Wang D, Li C, Ji C, Yao X, Wang PG, Jing Y, He Y, Shen CK.Typically, the antigen-specific antibodies constitute a small fraction-often estimated to be around 2-10 %-of the total IgG in the serum after immunization. This low percentage necessitates the use of purification techniques to enrich the antigen-specific antibodies for therapeutic or research purposes. This study introduces an affinity chromatography column using NHS-activated Sepharose as a matrix and the tetanus toxin subunit C, TeNT-Hc-C869A, as a ligand, enabling the purification of polyclonal antibodies with high specificity. This process improves antitoxin purity to over 95 %, effecti...
da Silveira BP, Kahn SK, Legere RM, Bray JM, Cole-Pfeiffer HM, Golding MC, Cohen ND, Bordin AI.Using a horse foal model, we show that enteral immunization of newborn foals with Rhodococcus equi overcomes neonatal vaccination challenges by reprogramming innate immune responses, inducing R. equi-specific adaptive humoral and cell-mediated immune responses and protecting foals against experimental pneumonia challenge. Foals were immunized twice via gavage of R. equi (immunized group) or saline (control group) at ages 1 and 3 days. At age 28 days, all foals were challenged intrabronchially with R. equi. Post-challenge, all 5 immunized foals remained healthy, whereas 67% (4/6) of control foa...
Matté YA, Baldasso DZ, Rezende MA, Lui JFM, Seibel AC, Guizzo JA, Frandoloso R, Kreutz LC.Lawsonia intracellularis is an obligatory intracellular bacterium associated with equine proliferative enteropathy (EPE), which significantly impacts equine health. Despite its clinical relevance, epidemiological and diagnostic approaches for this infection in horses have remained underexplored. This study aimed to evaluate the humoral immune response in horses immunized with an experimental vaccine for L. intracellularis and to determine the occurrence of anti-L. intracellularis antibodies in horses from southern Brazil using the flow cytometry antibody test (FCAT). Unassigned: A total of 12 ...
Gamage C, Holl W, Parreño V, Thieulent CJ, Balasuriya UBR, Vissani MA, Barrandeguy ME, Carossino M.Group A rotavirus (RVA) infections are a leading cause of neonatal diarrhoea in foals. Neonatal mice could serve as a useful tool to study the pathogenesis of equine RVA (ERVA) as well as a preclinical model for assessment of vaccine efficacy. This study aimed to comparatively evaluate the clinical, virological and pathological features of ERVA G3P[12] and G14P[12] infection in neonatal mice and compare them with porcine OSU G5P[7] and bovine UK G6P[5] RVA reference strains. Neonatal mice orally inoculated with equine, bovine and porcine RVA developed short-lived diarrhoea at variable rates, G...
Kutumbetov L, Myrzakhmetova B, Tussipova A, Zhapparova G, Tlenchiyeva T, Bissenbayeva K, Nurabayev S, Kerimbayev A.Equine rhinopneumonia, caused by equine herpesvirus types 1 and 4 (EHV-1 and EHV-4), continues to be a significant health and economic concern in the global equine industry, particularly in Kazakhstan. While vaccines targeting EHV-1 are available, there is currently no licensed monovalent vaccine for EHV-4, and existing formulations offer limited protection against this serotype. This study aimed to develop and evaluate a freeze-dried, live-attenuated EHV-4 vaccine with improved safety, stability, and immunogenicity. Methods: A field isolate of EHV-4 was attenuated through serial passaging in ...
Nemoto M, Kawanishi N, Kambayashi Y, Bannai H, Yamanaka T, Garvey M, Cullinane A, Yamayoshi S, Kawaoka Y, Tsujimura K.Reverse genetics (RG) technology is useful for quickly updating influenza vaccine strains. A high-yield backbone (i.e., six segments other than hemagglutinin and neuraminidase) derived from A/Puerto Rico/8/1934 (PR8) has been developed to improve the growth of avian and human influenza viruses. However, for equine influenza virus (EIV), an EIV-derived backbone may have better growth properties due to more-natural segment combinations. We compared the growth properties in eggs between the PR8 backbone and an EIV backbone from A/equine/Ibaraki/1/2007, a vaccine strain in Japan. The results showe...
Golen GS, Erganiş O, Balevi A. is an important bacterial pathogen and causes severe chronic granulomatous pneumonia in foals below 6 months of age. It has also become an opportunistic and emerging pathogen in immunocompromised humans. Vaccination is the most cost-effective strategy for controlling and preventing this infection. Although several potential virulence genes and candidate immunogens have been identified over the years, no effective vaccine is currently available to prevent disease in horses. Recently, bacterial vector vaccines have been shown to be promising for In this study, the gene of was cloned into P...
Roncaglia-Pereira VA, Dumard CH, Monteiro-Machado M, Melo PA, Fonseca J, Meirelles L, Cunha-Ribeiro L, Souza P, da Silva JL, Castilho L....In this study, we aim to report the persistent presence of anti-SARS-CoV-2 immunoglobulins in pre-immunized mare offspring. Three mares from Vital Brazil Institute were pre-immunized with recombinant SARS-CoV-2 spike protein and became pregnant during this period. After parturition, the mares' serum and colostrum/milk and foal serum were collected over 6 weeks. Our results have shown high and persistent presence of IgG and neutralizing antibodies over the weeks not only in the mares' serum, as expected, but in mares' colostrum/milk and foal serum as well-what were very surprising. This peculia...
Tolnai C, O'Sullivan C, Lőrincz M, Karvouni M, Tenk M, Marosi A, Forgách P, Paszerbovics B, Wagenhoffer Z, Kutasi O.West Nile virus (WNV) is a mosquito-borne neurotropic virus that causes neurologic disease in both humans and horses. Yet the long-term cellular immune response following natural infection in horses remains poorly understood. This study aims to evaluate the WNV-specific T-cell response in horses recovered from West Nile neuroinvasive disease (WNND). Twelve client-owned horses (4 Hungarian sport horses, 2 Lippizaners, 1 KWPN, 1 Shagya Arabian, 1 Friesian, 1 Gidran, 1 Andalusian, and 1 draft cross horse) with confirmed clinical WNV infection were enrolled, and peripheral blood mononuclear cells ...
Nemoto M, Kawanishi N, Kamei R, Furusho K, Kawauchi K, Yabuuchi Y, Oue Y, Uchida Y, Nishiura H, Reedy SE, Chambers TM, Li F, Bannai H, Yamanaka T....In April and May 2025, outbreaks of equine influenza occurred for the first time in 17 years in Japan. Equine influenza virus (EIV) of the H3N8 subtype was mainly detected in heavy draft horse populations in Kumamoto Prefecture and the Tokachi area of Hokkaido. In total, 10 EIVs were isolated from infected horses and then were used for genetic and serological analyses. Phylogenetic analysis of all eight genes revealed that all Japanese isolates were clustered with the Florida sublineage clade 1 (Fc1) viruses and were closely related to North American Fc1 viruses detected in 2024-2025. The resu...
Khan MZ, Ji Y, Fan X, Liu Y, Liu W, Wang C.Equine herpesvirus (EHV) infections represent a significant global veterinary and economic challenge affecting both horses and donkeys across all inhabited continents. This narrative review comprehensively examines the nine distinct EHV species (EHV-1 through EHV-9), their taxonomic classification within Alphaherpesvirinae and Gammaherpesvirinae subfamilies, and their diverse host tropism patterns. The complex molecular pathogenesis involves sophisticated viral glycoproteins (gK, gB, gC, gH, gM, gL, gG, gD, gI, gE) that orchestrate cellular invasion, immune evasion, and intercellular transmiss...
Conrad NL, Mazzoleni I, Abreu MC, Costa AV, Di Giácomo CP, Zorzi VSG, Leite FPL.Equine proliferative enteropathy (EPE), caused by Lawsonia intracellularis induces intestinal epithelial hyperplasia, resulting in malabsorption, weight loss, colic, and diarrhea. Despite its clinical and economic importance, no equine-specific vaccine is commercially available. Recombinant subunit vaccines are a safe and scalable alternative; however, their immunogenicity often requires improvement. Probiotic supplementation with Bacillus toyonensis may act as an immunomodulatory strategy to potentiate vaccine efficacy. This study aimed to evaluate the immunogenicity of a recombinant protein ...
Li Z, Yu T, Ge L, Lv S, Fu Q, Shi H.Equine herpesvirus type 1 (EHV-1) is a major veterinary pathogen causing significant economic losses in the livestock industry. Despite its impact, effective vaccines and targeted antiviral strategies remain limited, largely due to an incomplete understanding of host factors regulating viral replication and pathogenesis. Unassigned: To systematically identify host genes essential for EHV-1 infection, we established a BHK-21 cell line stably expressing Cas9 and performed a genome-wide CRISPR/Cas9 knockout screen using a pooled lentiviral single-guide RNA library. Significantly enriched candidat...
Yang Y, Guo K, Xu L, Guo W, Dong M, Liu W, Li S, Zhang Z, Chu X, Wang Y, Zhang Z, Hu Z, Wang X.Equine influenza (EI), caused by the equine influenza virus (EIV), is an acute respiratory disease that has become enzootic worldwide, resulting in frequent outbreaks and substantial economic losses within the equine industry. In this study, we developed a competitive enzyme-linked immunosorbent assay (NP-cELISA) for the detection of antibodies against the EIV nucleoprotein (NP). The assay was designed by coating plates with purified monoclonal antibodies (mAbs) against the NP protein, followed by simultaneous incubation of the test serum samples and HRP-NP antigen in a competitive binding rea...
Epizootic lymphangitis (EEL), caused by Histoplasma capsulatum var. farciminosum (HCF), is a neglected equine fungal disease lacking effective vaccines. The newly developed inactivated '8ZH' vaccine requires safety validation in the target species. Objective: To evaluate the biochemical, haematological and clinical safety of the inactivated HCF '8ZH' vaccine in foals. Methods: A controlled, single-blinded study was conducted on 30 clinically healthy foals (4-6 months), randomized into vaccinated (n = 15) and control (n = 15) groups. Vaccinated animals received a 5 mL intramuscular dose (...
van Rijn PA, Wernery U, Feddema AJ, Maris-Veldhuis MA, Joseph S, van Gennip RGP.African Horse Sickness (AHS) is a devastating vector-borne viral disease of equids with a mortality up to 95 % in naïve domestic horses. The causative African horse sickness virus (AHSV) is a distinct species of the genus Orbivirus of the family Sedoreoviridae, consisting of nine serotypes showing limited cross protection. AHSV is transmitted by Culicoides biting midges. Outbreaks cause huge economic losses in developing African countries. AHS has become a serious threat for countries outside Africa, since endemic Culicoides species in moderate climates appear competent vectors of the closel...
He L, Khine NO, Song J, Loubière C, Butaye P.Strangles, caused by the host-adapted subsp. (. ), imposes significant welfare and economic losses on the equine industry worldwide. Understanding its genomic features, virulence-associated genes (VAGs), antimicrobial resistance (AMR) and mobile genetic elements (MGEs) is essential for disease control and vaccine development. This study aimed to characterize the accessory genome composition, geographic distribution of VAGs and MGEs, and AMR profiles of . by a large-scale genomic analysis of global publicly available . sequences. All publicly available . sequences in the Sequence Read Arch...
Wang L, Zheng R, Li Z, Zhang L.Recent increases in cases of western equine encephalitis (WEE) in South America have raised significant concerns about the virus's potential to cause an endemic disease due to its adaptation to mosquito vectors. Currently, there are no effective vaccines or treatments for WEEV, despite ongoing research into various biochemical products in animal models. The virus presents different pathological effects depending on the host. In humans, WEEV infection leads to central nervous system damage, resulting in encephalitis and severe neurological sequelae, which underscores the need for further resear...
Centers A, Barnaby K, Goedeker S, Pignataro A, Tretyakova I, Lukashevich I, Pushko P, Chung D.There is a need for safe and effective vaccines against the Venezuelan equine encephalitis virus that infects both humans and equines. However, development of a live-attenuated vaccine using the TC-83 strain has been hampered by substantial reactogenicity and the potential for neuroinvasion. In this study, we demonstrate that V4020, a new TC-83-based investigational VEEV vaccine with redundant safety features preventing neuroinvasion and reversion, exhibited no neuroinvasion potential in a murine model. Following subcutaneous or intramuscular administration, a subset of mice that received the ...
Tinarwo M, Dennis SJ, Hitzeroth II, Meyers AE, Rybicki EP, Mbewana S.African horse sickness (AHS) is a severe, noncontagious disease of equines caused by the African horse sickness virus (AHSV). The virus has nine serotypes and is transmitted by the midge. AHS is endemic in South Africa and other sub-Saharan African countries. Currently, the disease is managed using a live attenuated vaccine manufactured by Onderstepoort Biological Products (OBP). Although this vaccine has been in use for decades, it has several drawbacks, including the possibility of reversion to virulence, and it does not allow for the differentiation of infected horses from vaccinated horse...
Abreu MC, Conrad NL, Gonçalves VS, Leite FPL.Probiotic microorganisms can stimulate an immune response and increase the efficiency of vaccines. For example, Bacillus toyonensis is a nonpathogenic, Gram-positive bacterium that has been used as a probiotic in animal supplementation. It induces immunomodulatory effects and increases the vaccine response in several species. This study aimed to evaluate the effect of B. toyonensis supplementation on the modulation of the immune response in horses vaccinated with recombinant Clostridium tetani toxin. Twenty horses were vaccinated twice, with an interval of 21 days between doses, and equally di...
Soliman R, Yousef M, Gelil SA, Aboul-Ella H.Strangles is a highly contagious disease of the equine upper respiratory tract caused by Streptococcus equi subspecies. Streptococcus equi subsp. equi (S. equi) and Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) was isolated, as local, hot, and field strains, from horses clinically suffering from respiratory distress. The isolated Streptococci were identified using bacteriological and molecular techniques. Four formulations of inactivated S. equi vaccines were developed and evaluated. The first formulation was prepared using the S. equi isolates, adjuvanted with MONTANIDE GEL adjuv...
Atwa AS, Gomaa L, Elmenofy W, Amer HM, Ahmed BM.Equine influenza (EI) is a transmissible viral respiratory sickness of the family. Two viruses, H7N7 and H3N8 caused EI; however, H7N7 has not been detected for decades. H3N8 has circulated and bifurcated into Eurasian and American lineages. The latter subsequently diversified into Kentucky, South America, and Florida sub-lineages. Florida clade 1 (FC1) and Florida clade 2 (FC2) strains are the only circulating EI viruses (EIVs) in the meantime. Immunization is considered the major means for the prevention and control of EI infection. Using disparate technologies and platforms, several vaccin...
Varela V, Costa M, Maciel C, Barbeito J, Barrera EE, Gutierre E, Correa A, Elgue M, Carrasco S, Larrosa MD, Pereira M, Correa J, Crosignani N....Anti-NGF monoclonal antibodies have recently been approved for treating degenerative joint disease, including osteoarthritis pain, in dogs and cats. However, their widespread use is limited by high cost and the requirement for repeated injections. Nerve Growth Factor and Substance P play central roles in the initiation and maintenance of inflammation and chronic pain in OA. There is a pressing need for new, safe, cost-effective therapies that target the underlying mechanisms of OA chronic pain. Here, we designed and produced a novel recombinant fusion protein, termed rNGFSP, which functions as...
