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.
Khusro A, Aarti C, Rivas-Caceres RR, Barbabosa-Pliego A.Equine herpesvirus-1 (EHV-1) is one of the most common and ubiquitous viral pathogens infecting equines, particularly horses worldwide. The EHV-1 is known to induce not only humoral but also cellular immune responses in horses. Respiratory distress, abortion in pregnant mares, neurological disorders, and neonatal foal deaths represent EHV-1 infection. Despite the limited success of inactivated, subunit, live, and DNA vaccines, over the past few decades, vaccination remains the prime preventive option to combat EHV-1 infection in horses. However, current vaccines lack the potentiality to protec...
Wu F, Zhang S, Zhang Y, Mo R, Yan F, Wang H, Wong G, Chi H, Wang T, Feng N, Gao Y, Xia X, Zhao Y, Yang S.Ebola virus infections lead to severe hemorrhagic fevers in humans and nonhuman primates; and human fatality rates are as high as 67%-90%. Since the Ebola virus was discovered in 1976, the only available treatments have been medical support or the emergency administration of experimental drugs. The absence of licensed vaccines and drugs against the Ebola virus impedes the prevention of viral infection. In this study, we generated recombinant baculoviruses (rBV) expressing the Sudan virus (SUDV) matrix structural protein (VP40) (rBV-VP40-VP40) or the SUDV glycoprotein (GP) (rBV-GP-GP), and SUDV...
Rutkowska DA, Mokoena NB, Tsekoa TL, Dibakwane VS, O'Kennedy MM.African horse sickness (AHS) is a severe arthropod-borne viral disease of equids, with a mortality rate of up to 95% in susceptible naïve horses. Due to safety concerns with the current live, attenuated AHS vaccine, alternate safe and effective vaccination strategies such as virus-like particles (VLPs) are being investigated. Transient plant-based expression systems are a rapid and highly scalable means of producing such African horse sickness virus (AHSV) VLPs for vaccine purposes. Results: In this study, we demonstrated that transient co-expression of the four AHSV capsid proteins in agroin...
Pan X, Wu Y, Wang W, Zhang L, Xiao G.Argentine haemorrhagic fever (AHF) is a rodent-borne disease with a lethality as high as ~30%, which is caused by the New World arenavirus, Junín virus (JUNV). It was once a major epidemic in South America and puts millions of people in Argentina at risk. Here, we aimed to develop horse antibodies or antibody fragments against JUNV. Before preparing the horse antibodies, a strategy to efficiently generate horse antisera was established based on comparisons among immunogens and immunization methods in both mice and horses. Antisera against JUNV were finally obtained by vaccinating horses with ...
Cook SJ, Li G, Zheng Y, Willand ZA, Issel CJ, Cook RF.Although the equine lentivirus (equine infectious anemia virus [EIAV]) poses a major threat to equid populations throughout most regions of the world, detailed knowledge concerning its molecular epidemiology is still in its infancy. Such information is important because the few studies conducted to date suggest there is extensive genetic variation between viral isolates that if confirmed has significant implications for future vaccine design and development of newer diagnostic procedures. Here, we avoid potential assembly artifacts inherent in composite sequencing techniques by using long-rang...
Marín-López A, Barreiro-Piñeiro N, Utrilla-Trigo S, Barriales D, Benavente J, Nogales A, Martínez-Costas J, Ortego J, Calvo-Pinilla E.African horse sickness virus (AHSV) is an insect-borne pathogen that causes acute disease in horses and other equids. In an effort to improve the safety of currently available vaccines and to acquire new knowledge about the determinants of AHSV immunogenicity, new generation vaccines are being developed. In this work we have generated and tested a novel immunization approach comprised of nonstructural protein 1 (NS1) of AHSV serotype 4 (AHSV-4) incorporated into avian reovirus muNS protein microspheres (MS-NS1) and/or expressed using recombinant modified vaccinia virus Ankara vector (MVA-NS1)....
Schnabel CL, Babasyan S, Rollins A, Freer H, Wimer CL, Perkins GA, Raza F, Osterrieder N, Wagner B.Equine herpesvirus type 1 (EHV-1) outbreaks continue to occur despite widely used vaccination. Therefore, development of EHV-1 vaccines providing improved immunity and protection is ongoing. Here, an open reading frame 2 deletion mutant of the neuropathogenic EHV-1 strain Ab4 (Ab4ΔORF2) was tested as a vaccine candidate. Three groups of horses ( = 8 each) were infected intranasally with Ab4ΔORF2 or the parent Ab4 virus or were kept as noninfected controls. Horses infected with Ab4ΔORF2 had reduced fever and nasal virus shedding compared to those infected with Ab4 but mounted similar ada...
Kydd JH, Hannant D, Robinson RS, Bryant N, Osterrieder N.Equid herpesvirus-1 (EHV-1) causes respiratory and neurological disease and late gestation abortion in pregnant mares. Current vaccines contain either inactivated or live EHV-1, but fail to provide complete clinical or virological protection, namely prevention of nasopharyngeal shedding and cell-associated viraemia. Thus, the development of novel products, such as modified live virus (MLV) vaccines which stimulate virus-specific, humoral and cell mediated immune responses more effectively remains a priority. Two groups of weaned foals (n = 6 each group) were used in a longitudinal, prospec...
Blanco-Lobo P, Rodriguez L, Reedy S, Oladunni FS, Nogales A, Murcia PR, Chambers TM, Martinez-Sobrido L.Vaccination remains the most effective approach for preventing and controlling equine influenza virus (EIV) in horses. However, the ongoing evolution of EIV has increased the genetic and antigenic differences between currently available vaccines and circulating strains, resulting in suboptimal vaccine efficacy. As recommended by the World Organization for Animal Health (OIE), the inclusion of representative strains from clade 1 and clade 2 Florida sublineages of EIV in vaccines may maximize the protection against presently circulating viral strains. In this study, we used reverse genetics tech...
Bosco-Lauth AM, Bowen RA.West Nile virus (WNV) (Flaviviridae: Flavivirus) was discovered in Africa more than 80 yr ago and became recognized as an avian pathogen and a cause of neurologic disease in horses largely during periodic incursions into Europe. Introduction of WNV into North America stimulated great anxiety, particularly in the equine industry, but also for pet owners and livestock producers concerned about the effect of WNV on other domestic animals. Numerous subsequent studies of naturally occurring and experimentally induced disease greatly expanded our understanding of the host range and clinical conseque...
Yazdansetad S, Mosavari N, Tadayon K, Mehregan I.Burkholderia mallei is the leading cause of glanders, a highly transmittable and an OIE-notifiable disease of equidae. Despite the importance of B. mallei, little is known about serodiagnosis of glanders. The present study aimed to develop an immunoblotting assay based on whole-cell proteome of B. mallei to enable accurate serodiagnosis of glanders. Methods: Three farm horses were subcutaneously immunized with a crude suspension (106 cfu/ml) of heat-inactivated B. mallei formulated with incomplete Freund's adjuvant (IFA) to achieve a hyperimmune sera panel. The immunization was done for 1, 14 ...
Dennis SJ, Meyers AE, Hitzeroth II, Rybicki EP.African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in sub-Saharan Africa. It is caused by nine different serotypes of the orbivirus African horse sickness virus (AHSV) and it is spread by Culicoid midges. The disease has significant economic consequences for the equine industry both in southern Africa and increasingly further afield as the geographic distribution of the midge vector broadens with global warming and climate change. Live attenuated vaccines (LAV) have been used with relative success for many decades but carry the risk o...
Vianna AM, Santos AC, Cunha RC, de Souza Stori de Lara AP, Weege GB, Leivas Leite FP.Equine theileriosis is a severe equine disease caused by the protozoan Theileria equi, which is prevalent in tropical and subtropical areas. In this study, a recombinant equi merozoite antigen-2 (rEMA-2) of T. equi was used as an immunogen. Two groups of 10 mice each were divided into control and vaccinated groups. Sixty mares seronegative for theileriosis were divided in two groups, one vaccinated and another group as a control animal. Mice and mares of the vaccinated groups were inoculated with 150 μL of the vaccine containing 50 μg of rEMA-2 and 2 mL of the vaccine containing 200 ...
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...
Rusnak JM, Glass PJ, Weaver SC, Sabourin CL, Glenn AM, Klimstra W, Badorrek CS, Nasar F, Ward LA.Licensure of a vaccine to protect against aerosolized Venezuelan equine encephalitis virus (VEEV) requires use of the U.S. Food and Drug Administration (FDA) Animal Rule to assess vaccine efficacy as human studies are not feasible or ethical. An approach to selecting VEEV challenge strains for use under the Animal Rule was developed, taking into account Department of Defense (DOD) vaccine requirements, FDA Animal Rule guidelines, strain availability, and lessons learned from the generation of filovirus challenge agents within the Filovirus Animal Nonclinical Group (FANG). Initial down-selectio...
de la Rosa G, Olvera F, Archundia IG, Lomonte B, Alagón A, Corzo G.Antivenoms are fundamental in the therapy for snakebites. In elapid venoms, there are toxins, e.g. short-chain α-neurotoxins, which are quite abundant, highly toxic, and consequently play a major role in envenomation processes. The core problem is that such α-neurotoxins are weakly immunogenic, and many current elapid antivenoms show low reactivity towards them. We have previously developed a recombinant consensus short-chain α-neurotoxin (ScNtx) based on sequences from the most lethal elapid venoms from America, Africa, Asia, and Oceania. Here we report that an antivenom generated by immu...
Bannai H, Tsujimura K, Nemoto M, Ohta M, Yamanaka T, Kokado H, Matsumura T.Equine herpesvirus type 1 (EHV-1) infection is a major cause of pyrexias in winter among Japanese racehorses. In 2014-2015, the Japan Racing Association (JRA) changed the EHV-1 vaccine from an inactivated vaccine to a live vaccine (both produced by Nisseiken). To evaluate the effect of changing the vaccines, the capacities of these vaccines to induce virus-neutralizing (VN) antibodies were compared, and an epizootiological investigation of EHV-1 was performed at the JRA Ritto Training Center during epizootic periods from 2010-2011 to 2016-2017. Results: Three-year-old horses that received the ...
Kim NY, Park KE, Lee YJ, Kim YM, Hong SH, Son WR, Hong S, Lee S, Ahn HB, Yang J, Seo JP, Lim YK, Yu CH, Hur GH, Jeong ST, Lee HS, Song K, Kang TJ....Botulinum neurotoxins (BoNTs), produced by , are the most toxic substances known. However, the number of currently approved medical countermeasures for these toxins is very limited. Therefore, studies on therapeutic antitoxins are essential to prepare for toxin-related emergencies. Currently, more than 10,000 Halla horses, a crossbreed between the native Jeju and Thoroughbred horses, are being raised in Jeju Island of Korea. They can be used for equine antitoxin experiments and production of hyperimmune serum against BoNT/A1. Instead of the inactivated BoNT/A1 toxoid, Halla horse was immunized...
Nemoto M, Yamayoshi S, Bannai H, Tsujimura K, Kokado H, Kawaoka Y, Yamanaka T.Equine influenza virus is an important pathogen for the horse industry because of its economic impact, and vaccination is a key control measure. Our previous work suggested that a mutation at position 144 in the hemagglutinin of Florida sublineage clade 2 viruses reduces the cross-neutralizing activity of antiserum against a former vaccine strain. To confirm this suggestion, here, we generated viruses by reverse genetics. Antibody titers against the mutated viruses were one-tenth to one-sixteenth of those against the former vaccine strain. Our findings confirm that this single amino acid subst...
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...
Ma X, Wang C, Zhang B, Xia L, Su Y.Strangles is a highly prevalent, extremely contagious, and occasionally lethal infectious disease affecting horses worldwide. Prophylactic antibiotics are ineffective in prevention of disease but are recommended for exposed horses at the first sign of fever and any horse obviously ill from strangles or with complications and there is an urgent need of a cost-effective, safe, efficacious vaccine. In the present study, we sought to develop effective vaccines by fusing the Streptococcus equi subspecies equi (S. equi) antigen SeM with the flagellin of Salmonella abortus equi FljB. We also explored...
Toh X, Soh ML, Ng MK, Yap SC, Harith N, Fernandez CJ, Huangfu T.Equine influenza is a major cause of respiratory infections in horses and can spread rapidly despite the availability of commercial vaccines. In this study, we carried out molecular characterization of Equine Influenza Virus (EIV) isolated from the Malaysian outbreak in 2015 by sequencing of the HA and NA gene segments using Sanger sequencing. The nucleotide and amino acid sequences of HA and NA were compared with representative Florida clade 1 and clade 2 strains using phylogenetic analysis. The Florida clade 1 viruses identified in this outbreak revealed numerous amino acid substitutions in ...
Rogger P, Herrmann N, Ottiger H.The registration of adverse events after the use of immunological veterinary medicinal products (VMP) is the aim of the vaccinovigilance reporting system in Switzerland. Adverse events comprise suspected adverse reactions and lack of expected efficacy. Since the Institute of virology and immunology (IVI) is the competent authority for the regulation of immunological VMP in Switzerland, the reporting system is administrated by the IVI. In 2018, 162 reports concerning authorized immunological VMP were received. While most of the reports were submitted by the marketing authorization holders (79%)...
McKenzie HC, Funk RA, Trager L, Werre SR, Crisman M.Potomac horse fever (PHF) is a potentially fatal enterocolitis of horses caused by Neorickettsia risticii. The disease was originally recognised almost 40 years ago in the state of Maryland in the US. It is now known to occur in many areas of North America, as well as having been described in South America and Europe. Monocomponent PHF vaccines are available, but clinical protection with vaccination has been reported to be inconsistent. Objective: This study was designed to assess the immunogenicity of a commercially available Potomac Horse Fever (PHF) vaccine when administered as either a mo...
To evaluate the immunological response following vaccination, 40 WNV serologically negative horses were selected and divided in two groups of 20 animals. One group was vaccinated (booster after 28 days) with a whole inactivated viral strain and the second group with a live recombinant canarypox virus expressing the genes coding for the WNV preM/E viral proteins. IgM, IgG and neutralizing antibodies were monitored by class specific ELISAs and serum neutralization assay for 360 days. In both groups, IgM antibodies were first detected 7 days post vaccination (dpv). However, in the group vaccinate...
Perkins G, Babasyan S, Stout AE, Freer H, Rollins A, Wimer CL, Wagner B.Equid herpesvirus-1 (EHV-1) outbreaks continue despite widely used vaccination. We demonstrated previously that an ORF1/ORF71 gene deletion mutant of the EHV-1 strain Ab4 (Ab4ΔORF1/71) is less virulent than its parent Ab4 virus. Here, we describe the Ab4 challenge infection evaluating protection induced by the Ab4ΔORF1/71 vaccine candidate. Susceptible control horses developed respiratory disease, fever, nasal shedding, and viremia. Full protection after challenge infection was observed in 5/5 previously Ab4 infected horses and 3/5 Ab4ΔORF1/71 horses. Two Ab4ΔORF1/71 horses developed short...
Zhao Y, Chang J, Zhang B, Tong P, Wang C, Ran D, Su Y.Equine herpesvirus 1 (EHV-1) induces serious respiratory infections, viral abortion, neurological signs, and neonatal mortality in horses. Despite the use of vaccines, EHV-1 infection also causes a high annual economic burden to the equine industry. The poor immunogenicity of and protection conferred by EHV-1 vaccines are the major factors responsible for the spread of EHV-1 infection. The present study examined the immunogenicity of a novel DNA vaccine co-expressing FliC, a flagellin protein, in Salmonella abortus equi and the gD protein of EHV-1. Mice and horses were immunized intramuscularl...
Racine T, Denizot M, Pannetier D, Nguyen L, Pasquier A, Raoul H, Saluzzo JF, Kobinger G, Veas F, Herbreteau CH.There is no vaccine or approved therapy against lethal Ebola virus (EBOV). We investigated a proven technology platform to produce polyclonal IgG fragments, F(ab')2, against EBOV. Horses immunized with nanoparticles harboring surface glycoprotein trimers of EBOV-Zaire/Makona produced anti-Ebola IgG polyclonal antibodies with high neutralization activity. Highly purified equine anti-Ebola F(ab')2 showed strong cross-neutralization of 2 Zaire EBOV strains (Gabon 2001 and Makona) and in vivo 3 or 5 daily F(ab')2 intraperitoneal injections provided 100% protection to BALB/c mice against lethal EBO...
Powell DG, Dwyer RM, Traub-Dargatz JL, Fulker RH, Whalen JW, Srinivasappa J, Acree WM, Chu HJ.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...
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...
Schnabel CL, Babasyan S, Rollins A, Freer H, Wimer CL, Perkins GA, Raza F, Osterrieder N, Wagner B.Equine herpesvirus type 1 (EHV-1) outbreaks continue to occur despite widely used vaccination. Therefore, development of EHV-1 vaccines providing improved immunity and protection is ongoing. Here, an open reading frame 2 deletion mutant of the neuropathogenic EHV-1 strain Ab4 (Ab4ΔORF2) was tested as a vaccine candidate. Three groups of horses ( = 8 each) were infected intranasally with Ab4ΔORF2 or the parent Ab4 virus or were kept as noninfected controls. Horses infected with Ab4ΔORF2 had reduced fever and nasal virus shedding compared to those infected with Ab4 but mounted similar ada...
León G, Herrera M, Vargas M, Arguedas M, Sánchez A, Segura Á, Gómez A, Solano G, Corrales-Aguilar E, Risner K, Narayanan A, Bailey C, Villalta M....In the current global emergency due to SARS-CoV-2 outbreak, passive immunotherapy emerges as a promising treatment for COVID-19. Among animal-derived products, equine formulations are still the cornerstone therapy for treating envenomations due to animal bites and stings. Therefore, drawing upon decades of experience in manufacturing snake antivenom, we developed and preclinically evaluated two anti-SARS-CoV-2 polyclonal equine formulations as potential alternative therapy for COVID-19. We immunized two groups of horses with either S1 (anti-S1) or a mixture of S1, N, and SEM mosaic (anti-Mix) ...
Minke JM, Toulemonde CE, Coupier H, Guigal PM, Dinic S, Sindle T, Jessett D, Black L, Bublot M, Pardo MC, Audonnet JC.To determine onset and duration of immunity provided by a 2- or 3-dose series of a new canarypox-vectored recombinant vaccine for equine influenza virus (rCP-EIV vaccine) expressing the hemagglutinin genes of influenza H3N8 virus strains A/eq/Kentucky/94 and A/eq/Newmarket/2/93 in ponies. Methods: Forty-nine 1- to 3-year-old male Welsh Mountain Ponies that were seronegative for equine influenza virus. Methods: Vaccinated and control ponies were challenged with aerosolized influenza virus A/eq/Sussex/89 (H3N8), representative of the Eurasian lineage of circulating influenza viruses. In trial 1,...
Chiam R, Sharp E, Maan S, Rao S, Mertens P, Blacklaws B, Davis-Poynter N, Wood J, Castillo-Olivares J.African horse sickness virus (AHSV) causes a non-contagious, infectious disease in equids, with mortality rates that can exceed 90% in susceptible horse populations. AHSV vaccines play a crucial role in the control of the disease; however, there are concerns over the use of polyvalent live attenuated vaccines particularly in areas where AHSV is not endemic. Therefore, it is important to consider alternative approaches for AHSV vaccine development. We have carried out a pilot study to investigate the ability of recombinant modified vaccinia Ankara (MVA) vaccines expressing VP2, VP7 or NS3 genes...
Hines MT, Paasch KM, Alperin DC, Palmer GH, Westhoff NC, Hines SA.Rhodococcal pneumonia is an important disease of young horses that is not seen in immunocompetent adults. Since all foals are normally exposed to Rhodococcus equi in their environment, we hypothesized that most develop protective immune responses. Furthermore, these antigen-specific responses were hypothesized to operate throughout adult life to prevent rhodococcal pneumonia. A better understanding of the mechanisms of immune clearance in adult horses would help define the requirements for an effective vaccine in foals. Adult horses were challenged with virulent R. equi by intrabronchial inocu...
Edlund Toulemonde C, Daly J, Sindle T, Guigal PM, Audonnet JC, Minke JM.Fifteen influenza-naive Welsh mountain ponies were randomly assigned to three groups of five. A single dose of a recombinant ALVAC vaccine was administered intramuscularly to five of the ponies, two doses, administered five weeks apart, were administered to five, and the other five served as unvaccinated, challenge controls. Two weeks after the completion of the vaccination programme, the ponies were all challenged by exposure to an aerosol of influenza virus A/eq/Newmarket/5/03. Their clinical signs were scored daily for 14 days according to a standardised scoring protocol, and nasal swabs we...
Matsuo E, Celma CC, Roy P.African horse sickness virus (AHSV), a member of the orbivirus genus of the family Reoviridae, is an insect-vectored pathogen of horses of concern to the equine industry. Studies on AHSV replication and pathogenesis have been hampered by the lack of reverse genetics allowing targeted mutation of viral genomes. We demonstrate that AHSV single-stranded RNA synthesized in vitro (core transcripts) is infectious and that there are distinct primary and secondary stages of the replication cycle. Transfection with a mixture of core transcripts from two different serotypes or a mixture of core transcri...
Woode GN, Bew ME, Dennis MJ.Inoculation at birth with a live attenuated strain of a bovine rotavirus isolated in the USA (scourvax-reo) induced protection in five gnotobiotic calves seven to 21 days later against a UK isolate of pathogenic bovine rotavirus. However, no protection was induced in three calves challenged three to five days after vaccination. There was a close antigenic relationship demonstrated between the two bovine rotavirus isolates. In contrast only one of three gnotobiotic calves inoculated with foal rotavirus, and one of three with human rotavirus, were protected against bovine rotavirus challenge. Pr...
Wang XF, Lin YZ, Li Q, Liu Q, Zhao WW, Du C, Chen J, Wang X, Zhou JH.The equine infectious anemia virus (EIAV) vaccine is the only attenuated lentiviral vaccine applied on a large scale that has been shown to be effective in controlling the prevalence of EIA in China. This vaccine was developed by successive passaging of a field-isolated virulent strain in different hosts and cultivated cells. To explore the molecular basis for the phenotype alteration of this vaccine strain, we systematically analyzed its genomic evolution during vaccine development. Results: Sequence analysis revealed that the genetic distance between the wild-type strain and six representati...
Cullinane A, Weld J, Osborne M, Nelly M, Mcbride C, Walsh C.The purpose of these studies was to examine the response of Thoroughbred foals and yearlings to different influenza vaccines and vaccination regimes. The horses' antibody levels against haemagglutinin, an established correlate of protection were measured by haemagglutination inhibition. The first study investigated the extent to which maternal antibodies interfered with the humoral response to a subunit vaccine. The findings suggest that repeat vaccination in the face of maternal antibodies may induce tolerance as defined by serological testing. The second study compared the immune response el...
Chambers TM, Holland RE, Tudor LR, Townsend HG, Cook A, Bogdan J, Lunn DP, Hussey S, Whitaker-Dowling P, Youngner JS, Sebring RW, Penner SJ....Flu Avert IN vaccine is a new, live attenuated virus vaccine for equine influenza. We tested this vaccine in vivo to ascertain 1) its safety and stability when subjected to serial horse to horse passage, 2) whether it spread spontaneously from horse to horse and 3) its ability to protect against heterologous equine influenza challenge viruses of epidemiological relevance. For the stability study, the vaccine was administered to 5 ponies. Nasal swabs were collected and pooled fluids administered directly to 4 successive groups of naïve ponies by intranasal inoculation. Viruses isolated from th...
Hulting G, Flock M, Frykberg L, Lannergård J, Flock JI, Guss B.Streptococcus equi ssp. equi causes strangles, a highly contagious and serious disease in the upper respiratory tract of horses. Streptococcus equi ssp. zooepidemicus, another subspecies of this genus, is regarded as an opportunistic commensal in horses. The present study describes the characterization of two novel immunoglobulin G (IgG) endopeptidases of these subspecies, IdeE2 and IdeZ2. Both enzymes display sequence similarities with two previously characterized IgG endopeptidases, IdeE of S. equi ssp. equi and IdeZ of S. equi ssp. zooepidemicus. IdeE2 and IdeZ2 display high substrate-speci...
A clinical evaluation of a new, purified, heat-treated equine rabies immunoglobulin (PHT-Erig), F(ab')2 preparation, was carried out in Thailand and in the Philippines-two countries where rabies is endemic. An initial prospective, randomised, controlled trial (Study 1), compared the safety and pharmacokinetics (serum concentrations of rabies antibodies) after administration either of PHT-Erig or of a commercially-available, equine rabies immune globulin (Erig PMC). A second trial (Study 2) simulated post-exposure rabies prophylaxis by using a reference cell culture vaccine, the purified Vero-c...
Hall RA, Khromykh AA.West Nile virus (WNV) is a mosquito-borne flavivirus that is emerging as a global pathogen. In the last decade, virulent strains of the virus have been associated with significant outbreaks of human and animal disease in Europe, the Middle East and North America. Efforts to develop human and veterinary vaccines have taken both traditional and novel approaches. A formalin-inactivated whole virus vaccine has been approved for use in horses. DNA vaccines coding for the structural WNV proteins have also been assessed for veterinary use and have been found to be protective in mice, horses and birds...
Rutkowska DA, Mokoena NB, Tsekoa TL, Dibakwane VS, O'Kennedy MM.African horse sickness (AHS) is a severe arthropod-borne viral disease of equids, with a mortality rate of up to 95% in susceptible naïve horses. Due to safety concerns with the current live, attenuated AHS vaccine, alternate safe and effective vaccination strategies such as virus-like particles (VLPs) are being investigated. Transient plant-based expression systems are a rapid and highly scalable means of producing such African horse sickness virus (AHSV) VLPs for vaccine purposes. Results: In this study, we demonstrated that transient co-expression of the four AHSV capsid proteins in agroin...
Defang GN, Khetawat D, Broder CC, Quinnan GV.The emergence of Hendra Virus (HeV) and Nipah Virus (NiV) which can cause fatal infections in both animals and humans has triggered a search for an effective vaccine. Here, we have explored the potential for generating an effective humoral immune response to these zoonotic pathogens using an alphavirus-based vaccine platform. Groups of mice were immunized with Venezuelan equine encephalitis virus replicon particles (VRPs) encoding the attachment or fusion glycoproteins of either HeV or NiV. We demonstrate the induction of highly potent cross-reactive neutralizing antibodies to both viruses usi...
Lopez J, Copps J, Wilhelmsen C, Moore R, Kubay J, St-Jacques M, Halayko S, Kranendonk C, Toback S, DeShazer D, Fritz DL, Tom M, Woods DE.Considerable advances in understanding of the disease caused by Burkholderia mallei have been made employing a combination of tools including genetic techniques and animal infection models. The development of small animal models has allowed us to assess the role of a number of putative virulence determinants in the pathogenesis of disease due to B. mallei. Due to the difficulties in performing active immunization studies in small animals, and due to the fact that the horse is the target mammalian species for glanders, we have initiated experimental studies on glanders in horses. Intratracheal ...
Burrows R, Goodridge D, Denyer MS.Vaccinated yearlings , two-year-old and in-foal pony mares with appropriate controls were exposed to aerosols of a subtype 1 virus one to two months after two or three vaccinations; all became infected. No obvious differences in the febrile responses, clinical signs and subsequent abortions were found between vaccinated and control mares. All vaccinated yearlings and two-year-old ponies developed a febrile respiratory disease but this was less severe than that suffered by the controls and the amounts and duration of virus shedding were reduced.
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...
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...
Perkins G, Babasyan S, Stout AE, Freer H, Rollins A, Wimer CL, Wagner B.Equid herpesvirus-1 (EHV-1) outbreaks continue despite widely used vaccination. We demonstrated previously that an ORF1/ORF71 gene deletion mutant of the EHV-1 strain Ab4 (Ab4ΔORF1/71) is less virulent than its parent Ab4 virus. Here, we describe the Ab4 challenge infection evaluating protection induced by the Ab4ΔORF1/71 vaccine candidate. Susceptible control horses developed respiratory disease, fever, nasal shedding, and viremia. Full protection after challenge infection was observed in 5/5 previously Ab4 infected horses and 3/5 Ab4ΔORF1/71 horses. Two Ab4ΔORF1/71 horses developed short...
Martínez-Torrecuadrada JL, Díaz-Laviada M, Roy P, Sánchez C, Vela C, Sánchez-Vizcaíno JM, Casal JI.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...
Perglione CO, Gildea S, Rimondi A, Miño S, Vissani A, Carossino M, Cullinane A, Barrandeguy M.In 2012, equine influenza (EI) virus was confirmed as the cause of outbreaks of respiratory disease in horses throughout South America. In Uruguay and Argentina, hundreds of vaccinated thoroughbred horses in training and racing facilities were clinically affected. Objective: To characterise the EI viruses detected during the outbreak in Uruguay and Argentina. Methods: Virus was detected in nasopharyngeal swabs by a pan-reactive influenza type A real-time RT-PCR. The nucleotide sequence of the HA1 gene was determined and analysed phylogenetically using mega 5 software. Amino acid sequences alig...
Minke JM, Fischer L, Baudu P, Guigal PM, Sindle T, Mumford JA, Audonnet JC.In this study, experimental canarypox virus (ALVAC) and plasmid DNA recombinant vaccines expressing the gB, gC and gD glycoproteins of EHV-1 were assessed for their ability to protect conventional ponies against a respiratory challenge with EHV-1. In addition, potential means of enhancing serological responses in horses to ALVAC and DNA vaccination were explored. These included co-administration of the antigen with conventional adjuvants, complexation with DMRIE-DOPE and co-expression of the antigen along with equine GM-CSF. Groups of EHV primed ponies were vaccinated twice intra-muscularly wi...
Paillot R, Grimmett H, Elton D, Daly JM.In the horse, conventional inactivated or subunit vaccines against equine influenza virus (EIV) induce a short-lived antibody-based immunity to infection. Alternative strategies of vaccination have been subsequently developed to mimic the long-term protection induced by natural infection with the virus. One of these approaches is the use of immune-stimulating complex (ISCOM)-based vaccines. ISCOM vaccines induce a strong antibody response and protection against influenza in horses, humans, and a mouse model. Cell-mediated immunity (CMI) has been demonstrated in humans and mice after ISCOM vacc...
Dawson TRMY, Horohov DW, Meijer WG, Muscatello G.Rhodococcus equi is recognised to cause chronic purulent bronchopneumonia in foals of less than 6 months of age. Virulent strains of the bacteria possess a large 80-90 kb plasmid encoding several virulence-associated proteins, including virulence-associated protein A (VapA), which is associated with disease. R. equi pneumonia can represent significant costs and wastage to the equine breeding industry, especially on stud farms where the disease is endemic. This article reviews knowledge of the equine immune response, both in the immune adult and susceptible neonate, with respect to this pathoge...
Garaicoechea L, Miño S, Ciarlet M, Fernández F, Barrandeguy M, Parreño V.P[12]G3 and P[12]G14 equine rotaviruses (ERVs) are epidemiologically important in horses. In Argentina, the prevalent ERV strains have been historically P[12]G3. The aim of this study was the detection and characterization of ERV strains circulating in foals in Argentina during a 17-year study (1992-2008). Additionally, the gene sequences of VP7, VP4 and NSP4 encoding genes of representative Argentinean ERV strains were determined and phylogenetic analyses were performed to elucidate the evolutionary relationships of the ERV strains in Argentina. ERVs were detected in 165 (21%) out of 771 diar...
