Virology in horses encompasses the study of viruses that affect equine species, including their biology, transmission, and impact on horse health. This field investigates viral pathogens that can lead to a range of diseases, from respiratory infections to neurological disorders. Common viruses affecting horses include equine influenza virus, equine herpesvirus, and West Nile virus. Understanding these viruses involves examining their genetic makeup, modes of transmission, and interactions with the equine immune system. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, and control measures of viral infections in horses.
Morgante O, Vance HN, Shemanchuk JA, Windsor R.The epizootic of equine encephalomyelitis in 1965 in Alberta was proved to be due to Western Encephalomyelitis virus infection by serological findings and virus isolations.Sixty-three horses of 88 tested, showed a diagnostic rise of CF antibodies to Western Encephalomyelitis virus. Western Encephalomyelitis virus was isolated from 5 brains of horses. Homologous antibodies were shown in 3 of these animals, the only ones from which blood specimens were received. For the first time virological evidence is given that Western Encephalomyelitis virus infection in horses is found in more areas of Alb...
Hampil B, Melnick JL.This paper summarizes the results of the second part of co-operative studies undertaken by the WHO International Reference Centre for Enteroviruses and a number of WHO Regional Virus Reference Centres, WHO Virus Collaborating Laboratories and other laboratories in a comprehensive testing programme of enterovirus equine antisera. The studies were designed to appraise the specificity of immune serum prepared in horses against 16 representative prototype enteroviruses (polioviruses 2 and 3, coxsackieviruses A7, B1, B2, B4, B5 and B6 and echoviruses 1, 2, 3, 5, 7, 9, 12 and 17). Tests for neutrali...
Sponseller ML, Binn LN, Wooding WL, Yager RH.Four field strains of western encephalitis virus were inoculated subcutaneously or intracranially (i/c) into recently weaned ponies. After s/c inoculation, 3 of the 4 strains produced an inapparent infection with a short period of viraemia. The 4th strain produced viraemia, fever, and signs of central nervous system disease. Viraemia occurred after intracranial inoculation with each strain; however, a variation in clinical response occurred, ranging from an inapparent infection to death. The disease pattern was characterized by three successive phases: viraemia, increased body temperature, and...
Harasawa R, Higashi T.Viral DNA obtained from the equine adenovirus propagated in equine transitional cell carcinoma (ETCC) cells and in equine fetal dermis cells were compared by cleaving with isoschizomeric restriction enzymes, HpaII and MspI, and then electrophoresed in 1.4 per cent agarose gels. Differences between the HpaII and MspI cleavage patterns were evident in viral DNA obtained only from the equine adenovirus propagated in ETCC cells, suggesting site specific methylation at CpG sequences.
Ferguson JA, Reeves WC, Hardy JL.Serologic studies in 24 ponies indicated that prevaccination antibodies to Venezuelan equine encephalomyelitis (VEE) virus (strain TC-83) had no influence on hemagglutination-inhibition (HI) antibody stimulation by western equine encephalomyelitis (WEE) or eastern equine encephalomyelits (EEE)-WEE vaccines. However, studies of the effects of VEE neutralizing antibodies on neutralizing antibody stimulation by the heterologous alphavirus vaccines were inconclusive. The VEE, WEE, and EEE antibody responses were studied in 18 VEE-vaccinated (strain TC-83) animals (13 ponies and 5 horses) at 9 to 1...
Singh G.A/eq-1 and A/eq-2 influenza viruses were isolated simultaneously from an epidemic of equine influenza in north India. Evidently, both types of equine influenza viruses circulated in the equine population at the same time.
Sánchez-Pacheco UA, Bahena-Mondragón BM, Hernández-Piedras FR, Soria-Osorio R, Meneses-Acosta A.The immunotherapy agents derived from horses are biological products that allow the neutralization of clinically relevant immunogens, such as the SARS-CoV-2 virus that causes COVID-19, or the neutralization of toxins present in the venoms of snakes, spiders, and other poisonous animals. Due to their importance, detecting adventitious viruses in equine hyperimmune serum (raw material in industrial processes) is a critical step to support the safety of products for human use, and, in consequence, it is a requirement for commercialization and distribution. The safety of the finished product is ba...
Weiblen R, Rabuske M, Rebelatto MC, Nobre VM, Canabarro TF.We report an outbreak of abortion due to equine herpesvirus (EHV) in 5 mares between 9 and 11 months of gestation, from a herd of 22 Thoroughbred mares. Equine herpesvirus was isolated from extracts of the liver, spleen and thymus but not from the lungs of a 9-month fetus grown in Rabbit Kidney (RK13) cells. The virus was identified by electron microscopy, where virus particles could be seen in the nucleus of infected cells, and by the fluorescent antibody technique with polyclonal antibodies against the whole virus. Anamnesis, necropsy, histopathology, bacteriology, and virology data suggest ...
Johnson AD, Eddy GA, Gangemi JD, Ramsburg HH, Metzger JF.Primary cell cultures, a continuous cell line, and a diploid cell line were grown on an artificial capillary system. The cells were subsequently infected with Venezuelan equine encephalitis virus, and viral replication was studied. Extracellular fluids harvested from this system contained high titers of virus and were relatively free of cell debris.
Karamendin K, Abishov A, Kydyrmanov A, Akhmetzhanova M.In 2011, there was an outbreak of a disease with mass abortions among horses in southeastern Kazakhstan. The AK-2011 strain was isolated from an aborted fetus and subsequently identified as equid alphaherpesvirus 1. Here, we describe the nearly complete genome sequence of the AK-2011 strain, attenuated for vaccine development.
Nemoto M, Okita N, Kitahata M, Bannai H, Tsujimura K, Kinoshita Y, Kambayashi Y, Cullinane A, Yamanaka T, Ohta M.A rapid and sensitive diagnostic method is needed to help prevent the spread of equine influenza virus. The cobas Influenza A/B & RSV test for the cobas Liat system (Roche Diagnostics) is based on real-time reverse transcription polymerase chain reaction and is designed to broadly detect influenza A virus RNA within 20 minutes. It detected a broad range of equine influenza virus strains, and detected equine influenza virus RNA from nasal swabs of infected horses at the same level as real-time reverse transcription polymerase chain reaction, although it returned some invalid results (7.7%)...
Razumov IA, Agapov EV, Pereboev AV, Protopopova EV, Lebedeva SD, Loktev VB.A comparative study of the antigenic structure of virulent strains and attenuated vaccine strains of Venezuelan equine encephalomyelitis virus (VEEV) by means of monoclonal antibodies has made it possible to investigate the antigenic structure of the envelope glycoproteins E1 and E2, and to specify their role in the development of antiviral immunity. On the E1 glycoprotein there are five nonoverlapping antigenic sites consisting of eight epitopes that are recognized by monoclonal antibodies; six sites consisting of twenty epitopes were found on the E2 glycoprotein. The monoclonal antibodies ag...
Kriegshäuser G, Cullinane A, Kuechler E, Skern T.Equine rhinitis B virus 1 (ERBV1), genus Erbovirus, family Picornaviridae, is a pathogen of horses which causes clinical and subclinical infection of the upper respiratory tract in horses. The virus is widespread in European horse populations and the current standard method for the detection of antibody against ERBV1 is by virus neutralisation (VN). VN tests, however, are labour-intensive and time-consuming, require tissue culture facilities, and generally do not provide same-day results. In this study, a protocol for the high-level expression and purification of recombinant virion protein 1 (...
Higashi T, Harasawa R.The three equine adenovirus strains isolated in different locations showed a similar cleavage pattern with HindIII and the DNA homology among the strains was confirmed by Southern blot hybridization. The three strains revealed differences in cleavage patterns with BamHI, EcoRI and PstI, suggesting the presence of DNA polymorphisms among equine adenoviruses.
Längerer L.Bernardino P, James K, Barnum S et al. What have we learned from 7 years of equine rhinitis B virus qPCR testing in nasal secretions from horses with respiratory signs. Vet Rec 2021; 188 (10): e26. DAS EQUINE RHINITIS-B-VIRUS (ERBV) HAT EINE HOHE INZIDENZ, IST IN SEINER BEDEUTUNG JEDOCH NUR WENIG ERFORSCHT. EINE INFEKTION MIT DEM ERBV äUßERT SICH IN SYMPTOMEN WIE FIEBER, ANOREXIE, LETHARGIE, NASENAUSFLUSS, HUSTEN, LYMPHADENOPATHIE UND ÖDEMEN DER DISTALEN GLIEDMAßEN. AUßERDEM TRETEN HäUFIG SUBKLINISCHE INFEKTIONEN AUF. DAS ZIEL DIESER STUDIE WAR, DIE HäUFIGKEIT DES NACHWEISES VON ERBV IM...
Urasawa S, Urasawa T, Ishizawa F, Taniguchi K.Bovine and equine sera were screened for poliovirus-reactive immunoglobulins (PRIgs) by means of neutralization and precipitation reactions with type 1 poliovirus. Bovine serum B1826 and B36 were found to contain such PRIgs from their reactivity to various PRIgs-resistant mutants of type 1 poliovirus origin. Neutralization and precipitation reactions with six mono-specific antibodies obtained by absorbing antiserum with each of the six different PRIgs-resistant virus mutants revealed that three antibodies were active in precipitation reaction while the others were substantially ineffective. On...
Iqbal J, Edington N.Equid herpesvirus 1 (EHV-1) is the most common cause of virus-induced abortion in horses. After primary infection the virus becomes latent predominantly in the respiratory tract lymph nodes and the genome can also be detected in the peripheral nervous system. The role of mouse as a feasible model for the establishment of latency and reactivation of EHV-1 was investigated. Intracerebral and intranasal infections of 3- and 17-day-old mice were made and virus replication was confirmed by virus isolation and detected by indirect immunofluorescence (IIF) in brain. For reactivation studies, the mice...
MacNeill AL, Micheloud JF, Parvin R, Gjessing M, Airas NA, Sant'Ana FJF, Adamek M.Zoonotic poxviruses, including monkeypox virus (MPV), the causative agent for Mpox disease, have gained significant media and scientific attention due to recent outbreaks in human populations across the globe. The increase in human cases of poxvirus infection is not unexpected, as routine vaccination against smallpox (a disease caused by the poxvirus variola virus, which cross protects against other orthopoxviruses) was discontinued in the 1980s after its eradication. Large numbers of vertebrate and invertebrate species are susceptible to infection by . Clinical signs and histologic lesions ca...
Rakaki ME, van der Walt M, Williams J, Venter M.We detected Shuni virus in horses and ovine fetuses and Shamonda virus in a caprine fetus in South Africa. We identified a Shuni/Shamonda virus reassortant in a horse and Shuni/Caimito, Shamonda/Caimito, and Shamonda/Sango virus reassortants in Culicoides midges. Continued genomic surveillance will be needed to detect orthobunyavirus infections in Africa.
Metz GE, Serena MS, Ocampos GM, Panei CJ, Fernandez VL, Echeverría MG.Equine arteritis virus (EAV) was isolated from a testicle of the presumable first stallion infected with EAV in Argentina. This virus isolate (named LT-LP-ARG) was confirmed by GP5-specific PCR and indirect immunofluorescence assays. The PCR product was sequenced, and the phylogenetic analysis revealed that the LT-LP-ARG strain of EAV forms a monophyletic group, together with other strains previously isolated in our laboratory (LP02 group). However, all Argentinean EAV strains belong to a polyphyletic group. We believe that the virus isolate presented in this report could be the origin of EAV ...
Vanderstraeten E, Bogaert L, Bravo IG, Martens A.Squamous cell carcinoma (SCC) represents the most common malignant tumour of the eye and external genitals in horses. Comparable to humans, papillomaviruses (PV) have been proposed as etiological agents of cancer in horses and recently, Equine papillomavirus type 2 (EcPV2) has been identified in genital SCCs. Hitherto it had never been demonstrated in ocular SCCs. The first goal of this study was to determine the prevalence of EcPV2 DNA in tissue samples from equine genital and ocular SCCs, genital papillomas and penile intraepithelial neoplasia (PIN) lesions, using EcPV2-specific PCR. The sec...
Schröer U, Lange A, Glatzel P, Ludwig H, Borchers K.The aim of the present study was to clarify whether an EHV-1 induced abortion can be prognosticated by an increase of antibody titres, virus shedding and/or viraemia and whether the current abortion diagnostic is suitable. In this context the immune response post immunization and a possible reactivation were of great interest. For this purpose blood samples of 32 mares between the ages of 5-21 years were regularly investigated during a period of two years before and after vaccination and pregnancy. Neutralization tests, indirect immunofluorescence tests as well as PCR and virus isolation were ...
White SD, Foley JE, Spiegel IB, Ihrke PJ.Equine sarcoidosis is a rare, multisystemic, noncaseating, granulomatous and lymphoplasmacytic disease of unknown etiology. A recent report described a horse with granulomatous skin disease displaying histologic, electron microscopic, and polymerase chain reaction (PCR) findings consistent with equine herpesvirus 2 (EHV-2). Objective: To investigate the presence of EHV-2 and equine herpesvirus 1 (EHV-1) in 8 horses with sarcoidosis. Methods: Eight horses with sarcoidosis, reported previously. Methods: Retrospective study. PCR assays of the tissues were performed to detect DNA associated with E...
Starick E.Serum samples from 72 stallions were examined for the occurrence of antibodies against equine arteritis virus, of which 41 animals (57%) were found to be positive. 32 of the seropositive stallions were then screened for persistent EAV infection, before and after the breeding season. Semen samples were investigated by RT-PCR followed by dot blot hybridization and nested PCR, and by virus isolation on cell cultures as well. The carrier state was virologically confirmed in 11 of 32 stallions (34%) during the first and in 9 of 20 (45%) during the second investigation. RT-PCR followed by confirmato...
Marquardt J, Heymer J, Heinz H, Deegen E, Adolf GR, Leibold W.Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is suf...
