The study of viral infections that affect equine species assesses the relationship between viruses and horses. Infections can lead to a range of clinical symptoms and may impact the health and performance of horses. Common equine viruses include Equine Influenza Virus, Equine Herpesvirus, and West Nile Virus, among others. Understanding the mechanisms of viral transmission, pathogenesis, and host immune responses is essential for developing effective prevention and treatment strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, molecular biology, and clinical management of viral infections in horses.
DOLL ER, WALLACE E, RICHARDS MG.Manninger and Csontos reported that mares inoculated with equine abortion virus developed a transient fever 2 to 4 days after pharyngeal or intravenous inoculation and that an uninoculated horse in contact with the experimentally inoculated mares contracted a febrile disease resembling equine influenza. Also, mares that had aborted virus-infected fetuses were resistant to inoculation with equine influenza virus. From these observations, they proposed that virus abortions were a manifestation of infection of pregnant mares by the equine influenza virus. In reports on equine virus abortions, Kre...
Chaintoutis SC, Diakakis N, Polizopoulou ZS, Dovas CI.Serum protein electrophoresis (SPE) is widely used to evaluate protein changes associated with several pathologies, aiming to assist clinical diagnosis. This study aimed to determine, for the first time, SPE profile changes in WNV-naturally infected horses. Sixty horses with different clinical and infection status (encephalitis, asymptomatic infection, and immunologically naïve) were included. Total protein concentrations were determined via an automated biuret method and SPE was performed using a cellulose acetate membrane-based automated system. Statistical analysis revealed significantly h...
Charles A, Kerckhove HV, De Maré L, Cassart D, Ficheroulle J, Pouyade GR, Tosi I.A Standardbred racehorse was presented for exercise intolerance, weight loss, pyrexia and facial deformity. Radiography and ultrasonography revealed periostitis and regional soft tissue swelling of maxillary bones. Computed tomography excluded any dental or sinus origin of these abnormalities. Further deformities on distal limbs and skin lesions appeared during hospitalization. Radiography identified bilateral periostitis and soft tissue swelling in the distal radius and metatarsal bones, as observed in the head, suggestive of hypertrophic osteopathy (HO). Skin biopsies revealed granulomatous ...
Mazzei M, Sorvillo B, Sgorbini M, Bindi F, Perelli A, Laus F.(1) Background: Respiratory problems may be associated with pathogens among which viruses may play an important role in causing or promoting clinical signs. However, traditional diagnostic methods for equine infectious diseases, such as PCR, are limited to known pathogens and often miss rare or novel viruses. Metagenomic next-generation sequencing is a transformative method that allows the sequencing of all genomes present in a sample. Recent studies have used next-generation sequences to identify viral sequences in horses with unexplained respiratory symptoms, revealing potential links betwee...
Mazzei M, Sorvillo B, Sgorbini M, Bindi F, Perelli A, Laus F.(1) Background: Respiratory problems may be associated with pathogens among which viruses may play an important role in causing or promoting clinical signs. However, traditional diagnostic methods for equine infectious diseases, such as PCR, are limited to known pathogens and often miss rare or novel viruses. Metagenomic next-generation sequencing is a transformative method that allows the sequencing of all genomes present in a sample. Recent studies have used next-generation sequences to identify viral sequences in horses with unexplained respiratory symptoms, revealing potential links betwee...
Padalino B, Pellegrini F, Felici M, Zappaterra M, Catella C, Cordisco M, Lorusso E, Cirone F, Pratelli A.Respiratory disorders (RDs) are a common transport-related welfare consequence in horses. This prospective study described the journeys of horses transported to two slaughterhouses in Italy, documented the prevalence of potentially RD-related pathogens, and identified possible predisposing factors. Data were recorded from arrival until 48 h after arrival and included the collection of Deep Nasopharyngeal Swabs (DNS), journey details and welfare assessment of horses (n = 155). PCR was used to quantify the presence of influenza A virus, reovirus, equine herpesvirus type 1 and 4, adenovirus, r...
Cardeti G, Manna G, Cersini A, Nardini R, Rosati S, Reina R, Cittadini M, Sittinieri S, Altigeri A, Marcario GA, Scicluna MT.The mechanisms of the innate immunity control of equine infectious anemia virus in horses are not yet widely described. Equine monocytes isolated from the peripheral blood of three Equine infectious anemia (EIA) seronegative horses were differentiated in vitro into macrophages that gave rise to mixed cell populations morphologically referable to M1 and M2 phenotypes. The addition of two equine recombinant cytokines and two EIA virus reference strains, Miami and Wyoming, induced a more specific cell differentiation, and as for other species, IFNγ and IL4 stimulation polarized horse macrophages...
Pusterla N, Barnum S, Lawton K, Craig B, James K.Equid alphaherpesvirus 4 (EqAHV4; Orthoherpesviridae, Varicellovirus equidalpha4; equine rhinopneumonitis virus) has seldom been associated with complications such as abortion and myeloencephalopathy, given the low tendency of this virus to induce viremia. We investigated the frequency of EqAHV4 viremia in horses with fever and respiratory signs. Case selection included all equids with EqAHV4 quantitative real-time PCR (qPCR)-positive nasal secretions (defined as EqAHV4 qPCR-positive cases) submitted to a diagnostic laboratory. Controls consisted of each case submitted before and after each Eq...
Sun Y, Yu YT, Castillo XO, Anderson R, Wang M, Sun Q, Tallmadge R, Sams K, Reboul G, Zehr J, Brown J, Wang X, Marra N, Stanhope B, Grenier J....Fever of unknown origin (FUO) without a respiratory component is a frequent clinical presentation in horses. Multiple pathogens, both tick-borne and enteric, can be involved as etiologic agents. An additional potential mechanism is intestinal barrier dysfunction. This case-control study aimed to detect and associate microbial taxa in blood with disease state. Areas known for a high prevalence of tick-borne diseases in humans were chosen to survey horses with FUO, which was defined as fever of 101.5°F or higher with no signs of respiratory illness or other recognisable diseases. Blood samples ...
Tsujimura K, Bannai H, Kambayashi Y, Nemoto M, Ohta M.Equid alphaherpesvirus 1 (EqAHV1; Orthoherpesviridae, Varicellovirus equidalpha1) spreads by viremia to susceptible organs. Because EqAHV1 circulates in the bloodstream in a cell-associated manner, serum samples are not considered valuable for detecting EqAHV1 and have therefore not been tested by highly sensitive detection methods such as real-time PCR (rtPCR). We investigated whether EqAHV1 could be detected by this method in equine serum samples. We performed rtPCR on archived sera and peripheral blood mononuclear cells (PBMCs) collected from 3 horses experimentally inoculated with EqAHV1. ...
Marchi S, Amodeo D, Peccetti B, De Palma I, Messina G, Montomoli E, Trombetta CM.Influenza D virus (IDV) is a novel influenza virus, first isolated from swine with influenza-like symptoms in the USA in 2011. To date, IDV circulation has been reported in various animal species such as cattle, pigs, horses with the ability to expand its range of hosts. UV radiation has been widely used for the disinfection of various sources such as water, air, and surfaces, especially in places at greater risk of contamination by viruses and bacteria, such as hospitals and health facilities. The aim of this study was to evaluate the potential virucidal effect of a violet-blue light against ...
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...
Keven JB, Walker ED.Eastern equine encephalomyelitis virus (EEEV) is endemic in Michigan, showing an upsurge in human cases and in infections of white-tailed deer, horses, and other animals in the past decade (2010-2020). However, blood-host associations of the enzootic mosquito vector Culiseta melanura in the Great Lakes region are poorly known compared with other better-studied regions. Vertebrate sources of blood meals of Cs. melanura collected from resting boxes were determined through sequencing of the mitochondrial cytochrome B gene generated from polymerase chain reaction. Thirty-six unique avian species w...
de la Cuesta-Torrado M, Vitale V, Velloso Alvarez A, Neira-Egea P, Diss C, Cuervo-Arango J.Equine herpesvirus 1-induced myeloencephalopathy has a significant impact on the equine industry. Nevertheless, the clinical variables that may affect the severity of the disease are still under investigation. The objective of this research is studying the relationship between the level of lymphopenia and vaccination status with the severity of the disease in horses at an event, considering whether they had been correctly vaccinated or not prior to exposure to EHV-1. Ten horses were admitted to a veterinary teaching hospital following an equine herpesvirus myeloencephalopathy outbreak during a...
Liu D, Zhao X, Wang X.Equine herpesvirus 1 (EHV-1), EHV-4, EHV-8, and EHV-9, are classified within the subfamily and are recognized as causative agents of respiratory, urogenital, and neurological disorders in horses. These viruses, collectively referred to as αEHVs, exhibits both unique and shared characteristics in terms of host interaction, pathogenesis, epidemiology, and immune evasion, which arise from both the identities and discrepancies among respective genomic homologs. The genomic architecture of αEHVs is similar to other members of the same subfamily, such as well-known HSV-1, VZV, and PRV. However, r...
Cullinane A, Garvey M, Dayot L, Lukaseviciute G.Equine rotavirus A (RVA) is a major cause of debilitating diarrhoea in neonatal foals globally. The aim of this study was to characterise RVA viruses currently circulating in Ireland and to identify risk factors associated with disease outbreaks. Of the 377 samples submitted during 2023 and 2024, 48 foals from 36 outbreaks were confirmed to be RVA-positive by real-time PCR. The viruses detected were genotyped by VP7 and VP4 gene sequencing. In 2024, the attending veterinary surgeon was contacted, and epidemiological data were collected. These included the vaccination status of the foal's dam a...
Al-Hammadi MA.Equine papillomavirus type 1 (EcPV-1) causes cutaneous papillomatosis in horses, which is characterized by benign, proliferative epithelial lesions. Despite its global presence, the prevalence and characterization of EcPV-1 in Arabian horses in Saudi Arabia have not been previously reported. Unassigned: This study is the first to identify and comprehensively analyze EcPV-1 in four Arabian horses presenting with multiple raised, verrucous lesions around the muzzle and lips. Unassigned: This study involved clinical examination, skin biopsy collection, histopathological examination, and molecular...
Suvanto MT, Truong Nguyen PT, Vauhkonen H, Olander V, Joensuu R, Culverwell CL, Kaansalo K, Hepojoki J, Vapalahti O, Korhonen EM, Smura T, Huhtamo E.The genus (, ) comprises several globally important vector-borne animal viruses, such as borne bluetongue virus, African horse sickness virus and epizootic haemorrhagic disease virus (EHDV). Orbiviruses that are associated with mosquitoes are a diverse group including established mosquito-borne animal pathogens such as the Peruvian horse sickness virus and phylogenetically related less well-characterized viruses isolated mostly from mammals. Although reported from various geographic regions, these viruses have not previously been detected in northern Europe. Using next-generation sequencing a...
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 ...
Hoxha I, Xhekaj B, Muja-Bajraktari N, Sekulin K, Unterköfler MS, Schlamadinger L, Situmorang T, Fuehrer HP, Obwaller AG, Camp JV, Walochnik J....West Nile virus (WNV, family Flaviviridae) is the most geographically widespread arbovirus affecting humans. It circulates between wild birds and mosquitoes, while humans and horses are dead-end hosts. In recent years, several outbreaks have been reported from European countries, including the Balkan Peninsula. In the Republic of Kosovo, a southern Balkan country, data on WNV are scarce, and neither mosquito monitoring nor WNV surveillance is established. To address this gap, we aimed to assess a first monitoring approach that should set the basis and support future large-scale activities in t...
Perkins GA, Wagner B, Rollins A, Sfraga H, Pearson E, Cercone M.To apply equine herpesvirus type 1 (EHV-1) antibody testing in nasal swabs and serum in nonclinical horses during a naturally occurring outbreak of (EHV-1). Previous experimental EHV-1 challenge studies showed stable serum anti-EHV-1 antibody concentrations paired with rapidly increasing nasal mucosal antibodies (mucAbs) prevent EHV-1 infection, viral shedding, and cell-associated viremia. From this, we hypothesized that EHV-1 antibody testing can confirm exposure in non-clinical horses during an outbreak. Unassigned: 2 horses with neurological signs from 1 farm were admitted to an equine hosp...
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...
Frisch V, Ramsauer AS, Preining I, Unterköfler MS, Fuehrer HP, Hofer M, Lyrakis M, Bouhsira E, Liénard E, Cavalleri JV.Equine hepacivirus (EqHV) from the family, has been detected in horses worldwide with a global RNA prevalence of up to 7.9%. While vertical transmission and iatrogenic transmission with infected blood products have been demonstrated for this virus, field infection rates suggest an additional horizontal transmission route. The aim of this study was to investigate the potential role of (Diptera, Muscidae) – a hematophagous fly that is found in stables with ruminants and horses as preferred hosts– in the transmission of EqHV RNA. From 2021 to 2022, were collected from three horse barns in ...
Scupham AJ.Many viruses mutate rapidly to adapt to host defenses, and for some of these viruses, the result is long-term infection in individual hosts. The work described here examines the infection and long-term maintenance of a newly identified virus, equine parvovirus-hepatitis (EqPV-H), in an individual horse. This description is possible because of a hypervariable region in the capsid gene; sequence variants were tracked by high-throughput sequencing of serum samples taken over a 16-year period. The data support the hypothesis that EqPV-H infection resulted in a sequence variant bottleneck. The cont...
Mohamed E, Van Cleemput J, Şahin B, Van den Broeck W, Boyen F, Nauwynck H.The equine respiratory and reproductive tract microbiomes are complex and subject to constant fluctuations. Among the microbial inhabitants, subsp. (SEZ) is recognized as the dominant bacterium. It is an opportunistic pathogen that may occasionally lead to various types of infections. A key virulence factor of SEZ is the streptolysin S (SLS) toxin, which is responsible for the characteristic β-hemolysis on blood agar and tissue damage. Viruses and bacteria may interact and aggravate lesions and disease. This study aimed to evaluate the impact of an SLS-containing supernatant from SEZ on the...
Busquets N, Gardela J, José-Cunilleras E, Solé A, Salvador MJ, Obón E, Molina-López R, Aranda C, Montalvo T, Corbella I, Bou-Monclús MA....West Nile virus (WNV), mainly transmitted by mosquitoes, poses significant health risks to humans and horses, particularly in endemic regions. The first detection of WNV lineage 2 in Spain was in 2017 in Catalonia (northeastern Spain). In 2023, WNV was confirmed in a young yellow-legged gull and a probable human case was notified within the urban settings. We aimed to define the zone of WNV circulation in the Barcelona Metropolitan Area where these infections occurred and the effectiveness of the One Health approach for early WNV detection. The Catalan WNV surveillance and control programs in...
Schliewert EC, Hooijberg EH, Goddard A.African horse sickness (AHS), caused by the vector-borne African horse sickness virus (AHSV), is endemic to sub-Saharan Africa and infection results in high mortality in naïve equine populations. Clinical signs include submucosal petechiae and prolonged bleeding post venepuncture indicative of hypocoagulation. Pathological activation of haemostasis may result from tissue factor expression as a result of vascular endothelial damage or dysfunction, the proposed pathologic mechanism in AHS, potentially resulting in disseminated intravascular coagulation (DIC). Objective: To describe haemostatic ...
Cooper CJ, Arroyo LG, Hammermueller JD, Botts MM, Pearl DL, Wootton SK, Lillie BN.Equine herpesvirus-1 (EHV-1) is ubiquitous in the horse population, but prevalence estimates have ranged from 3 to 88% depending on the population and method of sampling. No prevalence studies have been carried out in Ontario, Canada. The objective of this study was to measure the prevalence of EHV-1 shedding in healthy broodmares in Ontario. A total of 381 mares from 42 farms in Ontario were sampled, including pregnant and barren broodmares. Samples were collected from the nose, vagina, and blood of each mare up to 6 times from December 2016 through October 2017 using a cross-sectional study ...
Acevedo-Jiménez GE, Morales-González C, Akbarin MM, Rodríguez-Murillo C, González-Fernández VD, Avila-De la Vega LM, García-Flores MM....Equine infectious anemia virus (EIAV) is a globally significant equine pathogen, and its control relies on effective serological surveillance. The agar gel immunodiffusion (AGID) test, the WOAH-prescribed method, has limitations in sensitivity. This study developed and validated an indirect ELISA using a synthetic peptide derived from a conserved region of the EIAV gp90 surface glycoprotein. The assay was evaluated using 773 horse sera from the Metropolitan Zone of the Valley of Mexico and compared to the AGID test. The gp90-EIAV ELISA demonstrated a sensitivity of 85.3 % and a specificity o...
Leo LK, Bergvall KE.Equine aural plaque caused by equine papilloma viruses is common worldwide and affected horses can show severe clinical signs. Due to its viral aetiology, in some countries affected horses are not allowed to compete. Since lesions persist, showing no spontaneous regression, effective and safe treatment is required. Currently, the only treatment with consistent efficacy is imiquimod. Treatment time is prolonged and adverse effects are common. In humans, papilloma warts are successfully and safely treated with topical nitric-zinc complex solutions inducing a painless caustic effect. Objective: T...
Martano M, Montagnaro S, Power K, Cuccaro B, Cutarelli A, Maiolino P, Restucci B.This study investigated the presence of δ bovine papillomaviruses (BPV-1, BPV-2, BPV-13, BPV-14) in equine skin lesions from Southern Italy, focusing on equine sarcoids and their histopathological correlations. 63 equine skin samples were analysed using PCR and sequencing for BPV detection, and their histopathological features were assessed. BPV DNA was detected in 69.84% of the samples, with BPV-1 and BPV-2 being the most prevalent genotype, followed by BPV-13, while BPV-14 was not detected. BPV DNA was also found in non-sarcoid tumours and non-neoplastic conditions. Histopathological analys...
