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.
Turan N, Yildirim F, Altan E, Sennazli G, Gurel A, Diallo I, Yilmaz H.The aim of the present study was to investigate abortion storms that occurred in the Marmara region of Turkey in 2008-2009 using a real-time PCR. Two aborted foetuses were necropsied and histo-pathological findings reported herein. Ten lungs, 3 brains and one nasal swab from 10 aborted foetuses, 6 nasal swabs and 3 vaginal swabs from aborting mares were included in this study. EHV-1 was isolated from the lung, liver and brain of 1 aborted foetus. EHV-1 DNA was detected in the lungs, livers and spleens of 2 necropsied foetuses and in 3 lungs from 10 foetuses submitted for diagnosis. A brain fro...
Pennick KE, McKnight CA, Patterson JS, Latimer KS, Maes RK, Wise AG, Kiupel M.Immunohistochemistry (IHC) and in situ hybridization (ISH) can be used either to detect or to differentiate between Eastern equine encephalitis virus (EEEV) and West Nile virus (WNV) within formalin-fixed, paraffin-embedded (FFPE) brain tissue of horses. To compare the diagnostic sensitivity and specificity of ISH and IHC, FFPE brain tissue from 20 EEEV-positive horses and 16 WNV-positive horses were tested with both EEEV and WNV oligoprobes and EEEV- and WNV-specific antibodies. Reverse transcription polymerase chain reaction (RT-PCR) for detection of EEEV and WNV was used as the gold standar...
Gordon AN, Marbach CR, Oakey J, Edmunds G, Condon K, Diviney SM, Williams DT, Bingham J.A 5-year-old Australian stock horse in Monto, Queensland, Australia, developed neurological signs and was euthanized after a 6-day course of illness. Histological examination of the brain and spinal cord revealed moderate to severe subacute, nonsuppurative encephalomyelitis. Sections of spinal cord stained positively in immunohistochemistry with a flavivirus-specific monoclonal antibody. Reverse transcription polymerase chain reaction assay targeting the envelope gene of flavivirus yielded positive results from brain, spinal cord, cerebrospinal fluid, and facial nerve. A flavivirus was isolate...
Malik P, Bálint A, Dán A, Pálfi V.Equine herpesvirus-1 (EHV-1) can be classified into distinct groups by single nucleotide polymorphisms (SNPs) in their genomes. Only a few of these can be associated with a special attribute of the virus. Differences in the ORF30 region can determine the neuropathogenic potential, while by substitutions in the ORF68 region several strain groups can be made. In previous studies no connection was found between the neuropathogenic potential and the SNPs in ORF68, but the occurrence of members of distinct groups in different outbreaks can facilitate epidemiological investigations because the geogr...
Burgess BA, Tokateloff N, Manning S, Lohmann K, Lunn DP, Hussey SB, Morley PS.There is little information on the duration of nasal shedding of EHV-1 from horses with naturally occurring equine herpesvirus myeloencephalopathy (EHM). Objective: To evaluate the duration of nasal shedding of EHV-1 in horses affected by EHM. Methods: One hundred and four horses naturally exposed to EHV-1, 20 of which had clinical signs of EHM. Methods: All horses on affected premises were monitored. Those horses developing EHM were sampled in a longitudinal outbreak investigation. Nasal swabs were collected daily from 16 of 20 horses affected by EHM. A qPCR was performed on 98 of 246 nasal s...
Sykora S, Samek L, Schönthaler K, Palm F, Borzacchiello G, Aurich C, Brandt S.Squamous cell carcinomas (SCC) are malignant tumours arising from keratinocytes. In horses, there is increasing evidence for Equus caballus papillomavirus type 2 (EcPV-2) being causally involved in SCC development. However, only little is known regarding intralesional transcription of the virus, and sparse information on the incidence of EcPV-2 infection in healthy equids is available so far. Using RT-PCR, total mRNA from 8 EcPV-2 DNA-positive and 1 EcPV-2 negative SCC/SCC precursor lesions was screened for the presence of EcPV-2 E6 and E1 transcripts. Using PCR, we tested 193 sample specimens...
Yamanaka T, Bannai H, Nemoto M, Tsujimura K, Kondo T, Muranaka M, Hobo S, Minamijima YH, Yamada M, Matsumura T.Equine influenza A virus (EIV) of the H3N8 subtype is an important pathogen causing acute respiratory disease in horses. Peramivir is a selective inhibitor of the influenza virus neuraminidase (NA). The characteristics of peramivir are not only its capacity for parenteral administration, but also its strong affinity for NA and slow off-rate from the NA-peramivir complex, suggesting that it could lead to a prolonged inhibitory effect and thus allow a lower dosing frequency. The aims of this study were to evaluate the inhibitory efficacy of peramivir against the NA activities of EIV in vitro and...
van Eeden C, Williams JH, Gerdes TG, van Wilpe E, Viljoen A, Swanepoel R, Venter M.To determine which agents cause neurologic disease in horses, we conducted reverse transcription PCR on isolates from of a horse with encephalitis and 111 other horses with acute disease. Shuni virus was found in 7 horses, 5 of which had neurologic signs. Testing for lesser known viruses should be considered for horses with unexplained illness.
Pretorius A, Van Kleef M, Van Wyngaardt W, Heath J.African horsesickness (AHS) is an infectious but noncontagious viral disease affecting all species of Equidae. The recall immune response of AHSV naïve horses immunised with an attenuated African horsesickness virus serotype 4 (AHSV4) was characterised using immune assays including ELISPOT, real-time PCR (qPCR) and flow cytometry. The recall immune response detected in PBMC isolated from three inoculated horses showed an upregulation of circulating B lymphocytes that correlated with elevated IL-4 mRNA expression indicative of humoral immunity, but reduced frequency of CD4⁺ cells. In additio...
Fuentealba NA, Sguazza GH, Eöry ML, Valera AR, Pecoraro MR, Galosi CM.Equid herpesvirus 1 (EHV-1) infection has a significant economic impact on equine production, causing abortion, respiratory disease, neonatal death and neurological disorders. The identification of specific EHV-1 genes related to virulence and pathogenicity has been the aim of several research groups. The purpose of the present study was to analyze different genomic regions of Argentinean EHV-1 strains and to determine their possible relationship with virulence or clinical signs. Twenty-five EHV-1 Argentinean isolates recovered from different clinical cases between 1979 and 2007 and two refere...
Ma G, Feineis S, Osterrieder N, Van de Walle GR.Major histocompatibility complex class I (MHC-I) molecules play an important role in host immunity to infection by presenting antigenic peptides to cytotoxic T lymphocytes (CTLs), which recognize and destroy virus-infected cells. Members of the Herpesviridae have developed multiple mechanisms to avoid CTL recognition by virtue of downregulation of MHC-I on the cell surface. We report here on an immunomodulatory protein involved in this process, pUL56, which is encoded by ORF1 of equine herpesvirus type 1 (EHV-1), an alphaherpesvirus. We show that EHV-1 pUL56 is a phosphorylated early protein w...
Barbić L, Lojkić I, Stevanović V, Bedeković T, Starešina V, Lemo N, Lojkić M, Madić J.Equine herpesvirus type 1 (EHV-1) is a worldwide spread pathogen of horses. It can cause abortion, respiratory and neurological disease and consequentially significant economic losses in equine industries. During 2009, two outbreaks of EHV-1 were confirmed in two stud farms in Eastern Croatia. The first outbreak occurred in February following the import of 12 horses from USA, serologically negative to EHV-1 before transport. Four mares aborted in the late stage of pregnancy and one perinatal death was recorded. Other six mares showed clinical signs of myeloencephalopathy with fatal end in four...
Vairo S, Vandekerckhove A, Steukers L, Glorieux S, Van den Broeck W, Nauwynck H.Equine viral arteritis (EVA) is an infectious disease with variable clinical outcome. Outbreaks, causing important economic losses, are becoming more frequent. Currently, there is a shortage of pathogenesis studies performed with European strains. In the present study, eight seronegative ponies were experimentally inoculated with the Belgian strain of equine arteritis virus (EAV) 08P178 (EU-1 clade) and monitored daily for clinical signs of EVA. Nasopharyngeal swabs, ocular swabs, bronchoalveolar cells and blood were collected for virological and serological testing. Two ponies were euthanized...
Capomaccio S, Willand ZA, Cook SJ, Issel CJ, Santos EM, Reis JK, Cook RF.The genetically distinct wild horse herds inhabiting Shackleford Banks, North Carolina are probably the direct descendents of Spanish stock abandoned after failed attempts to settle mid-Atlantic coastal regions of North America in the Sixteenth Century. In a 1996 island survey, 41% of the gathered horses were discovered seropositive for Equine Infectious Anemia Virus (EIAV) with additional cases identified in 1997 and 1998. As a result of their unique genetic heritage, EIAV seropositive individuals identified in the two latter surveys were transferred to a quarantine facility on the mainland. ...
Mattar S, Komar N, Young G, Alvarez J, Gonzalez M.We prospectively sampled flavivirus-naïve horses in northern Colombia to detect West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) seroconversion events, which would indicate the current circulation of these viruses. Overall, 331 (34.1%) of the 971 horses screened were positive for past infection with flaviviruses upon initial sampling in July 2006. During the 12-month study from July 2006-June 2007, 33 WNV seroconversions and 14 SLEV seroconversions were detected, most of which occurred in the department of Bolivar. The seroconversion rates of horses in Bolivar for the period of M...
Reis JK, Diniz RS, Haddad JP, Ferraz IB, Carvalho AF, Kroon EG, Ferreira PC, Leite RC.Equine infectious anemia (EIA) is an important viral infection affecting horses worldwide. The course of infection is accompanied generally by three characteristic stages: acute, chronic and inapparent. There is no effective EIA vaccine or treatment, and the control of the disease is based currently on identification of EIAV inapparent carriers by laboratory tests. Recombinant envelope protein (rgp90) was expressed in Escherichia coli and evaluated via enzyme-linked immunosorbent assay (ELISA). There was an excellent agreement (95.42%) between the ELISA results using rgp90 and agar gel immunod...
García-Bocanegra I, Jaén-Téllez JA, Napp S, Arenas-Montes A, Fernández-Morente M, Fernández-Molera V, Arenas A.West Nile virus (WNV) is a mosquito-transmitted flavivirus recognized as an emerging and re-emerging pathogen in different countries. This study describes the monitoring of the first WNV epidemic in Spain between 2010 and 2011. Between September and December 2010, 36 outbreaks of WNV in horses were reported in three different provinces of Andalusia (southern Spain), with no apparent spread outside this area. The temporal distribution and the clinical signs observed during the WNV epidemic in Spain were, in general, similar to those reported in Europe and in the Mediterranean Basin. Morbidity, ...
Miszczak F, Legrand L, Balasuriya UB, Ferry-Abitbol B, Zhang J, Hans A, Fortier G, Pronost S, Vabret A.During the summer of 2007, an outbreak of equine viral arteritis (EVA) occurred in Normandy (France). After investigation, a link was suggested between an EAV carrier stallion (A) and the index premise of the outbreak. The full-length nucleotide sequence analysis of a study reference strain (F27) isolated from the lung of a foal revealed a 12,710 nucleotides EAV genome with unique molecular hallmarks in the 5'UTR leader sequence and the ORF1a sequence encoding the non-structural protein 2. The evolution of the viral population in the persistently infected Stallion A was then studied by cloning...
Ferris NP, Clavijo A, Yang M, Velazquez-Salinas L, Nordengrahn A, Hutchings GH, Kristersson T, Merza M.Two lateral flow devices (LFD) for the detection of vesicular stomatitis (VS) virus (VSV), types Indiana (VSV-IND) and New Jersey (VSV-NJ) were developed using monoclonal antibodies C1 and F25VSVNJ-45 to the respective VSV serotypes. The performance of the LFDs was evaluated in the laboratory on suspensions of vesicular epithelia and cell culture passage derived supernatants of VSV. The collection of test samples included 105 positive for VSV-IND (92 vesicular epithelial suspensions and 13 cell culture antigens; encompassing 93 samples of subtype 1 [VSV-IND-1], 9 of subtype 2 [VSV-IND-2] and 3...
Goodman LB, Wimer C, Dubovi EJ, Gold C, Wagner B.Equine herpesvirus 1 (EHV-1) induces a variety of disease manifestations, including respiratory disease, abortions, and myeloencephalopathy. Several vaccines are commercially available but could not previously be distinguished by serologic testing from infection with EHV-1 (or the closely related EHV-4). Currently available vaccines are not reliably protective against the severe manifestations of the disease, including fatal myeloencephalopathy. We determined immunological parameters that can differentiate vaccinated from previously infected animals by comparing humoral and cellular EHV-1-spec...
Yao S, Qi J, Liu J, Chen R, Pan X, Li X, Gao F, Xia C.In order to clarify the structure and the peptide-presentation characteristics of the equine major histocompatibility complex (MHC) class I molecule, a complex of equine MHC class I molecule (ELA-A1 haplotype, 7-6 allele) with mouse β(2)-microglobulin and the cytotoxic T lymphocyte (CTL) epitope Env-RW12 (RVEDVTNTAEYW) derived from equine infectious anaemia virus (EIAV) envelope protein (residues 195-206) was refolded and crystallized. The crystal, which belonged to space group P2(1), diffracted to 2.3 Å resolution and had unit-cell parameters a = 82.5, b = 71.4, c = 99.8 Å, β = 102.9°. T...
Aleman M, Pickles KJ, Simonek G, Madigan JE.Trigeminal neuralgia or neuropathic pain has been regarded as a putative cause of idiopathic headshaking in horses. Equine herpesvirus-1 (EHV-1) infection and resultant postherpetic pain have been suggested as a possible cause of such neuropathic pain. Objective: To determine the presence of EHV-1 in the trigeminal ganglia of horses with idiopathic headshaking. Methods: Nineteen horses: control (n = 11, 9 geldings, 2 mares, median age 11 years) and headshaking (n = 8, all geldings, median age 11.5 years) horses were sourced from the equine research herd and caseload at the Veterinary Medical T...
Matthijnssens J, Miño S, Papp H, Potgieter C, Novo L, Heylen E, Zeller M, Garaicoechea L, Badaracco A, Lengyel G, Kisfali P, Cullinane A, Collins PJ....In this study, the complete genome sequences of seven equine group A rotavirus (RVA) strains (RVA/Horse-tc/GBR/L338/1991/G13P[18], RVA/Horse-wt/IRL/03V04954/2003/G3P[12] and RVA/Horse-wt/IRL/04V2024/2004/G14P[12] from Europe; RVA/Horse-wt/ARG/E30/1993/G3P[12], RVA/Horse-wt/ARG/E403/2006/G14P[12] and RVA/Horse-wt/ARG/E4040/2008/G14P[12] from Argentina; and RVA/Horse-wt/ZAF/EqRV-SA1/2006/G14P[12] from South Africa) were determined. Multiple novel genotypes were identified and genotype numbers were assigned by the Rotavirus Classification Working Group: R9 (VP1), C9 (VP2), N9 (NSP2), T12 (NSP3), ...
García-Bocanegra I, Jaén-Téllez JA, Napp S, Arenas-Montes A, Fernández-Morente M, Fernández-Molera V, Arenas A.TO THE EDITOR: West Nile virus (WNV) is a member of the genus Flavivirus within the Japanese encephalitis antigenic complex. The enzootic virus cycle involves transmission between avian hosts and ornithophilic mosquitoes, whereas humans and horses are considered dead-end hosts. Given the recent increase of WNV infection in humans and horses in Europe, concern has been raised regarding public and animal health.
Madani H, Casal J, Alba A, Allepuz A, Cêtre-Sossah C, Hafsi L, Kount-Chareb H, Bouayed-Chaouach N, Saadaoui H, Napp S.Antibodies against bluetongue virus were detected in cattle, sheep, goats, and camels in Algeria in 2008. Antibodies against epizootic hemorrhagic disease virus were detected in cattle, but antibodies against African horse sickness virus were not detected in horses and mules. Epizootic hemorrhagic disease in northern Africa poses a major risk for the European Union.
Marsh GA, Haining J, Hancock TJ, Robinson R, Foord AJ, Barr JA, Riddell S, Heine HG, White JR, Crameri G, Field HE, Wang LF, Middleton D.Hendra virus (HeV) is a highly pathogenic zoonotic paramyxovirus harbored by Australian flying foxes with sporadic spillovers directly to horses. Although the mode and critical control points of HeV spillover to horses from flying foxes, and the risk for transmission from infected horses to other horses and humans, are poorly understood, we successfully established systemic HeV disease in 3 horses exposed to Hendra virus/Australia/Horse/2008/Redlands by the oronasal route, a plausible route for natural infection. In 2 of the 3 animals, HeV RNA was detected continually in nasal swabs from as ea...
Oura CA, Batten CA, Ivens PA, Balcha M, Alhassan A, Gizaw D, Elharrak M, Jallow DB, Sahle M, Maan N, Mertens PC, Maan S.Prior to the recent outbreak of equine encephalosis in Israel in 2009, equine encephalosis virus (EEV) had only been isolated from equids in South Africa. In this study we show the first evidence for the circulation of EEV beyond South Africa in Ethiopia, Ghana and The Gambia, indicating that EEV is likely to be freely circulating and endemic in East and West Africa. Sequence analysis revealed that the EEV isolate circulating in The Gambia was closely related to an EEV isolate that was isolated from a horse from Israel during the EEV outbreak in 2009, indicating that the two viruses have a com...
van der Meulen K, Caij B, Pensaert M, Nauwynck H.In vitro studies demonstrated that most equine herpesvirus 1 (EHV-1)-infected peripheral blood mononuclear cells (PBMC) do not expose viral envelope proteins on their surface. This protects them against antibody-dependent lysis. We examined whether viral envelope proteins are also undetectable on infected PBMC during cell-associated viremia. Further, surface expression of major histocompatibility complex (MHC)-I was examined, since MHC-I assists in making infected cells recognizable for cytotoxic T-lymphocytes (CTL). Four ponies, previously exposed to EHV, and two ponies that had no contact wi...
Conze TM, Bagó Z, Revilla-Fernández S, Schlegel J, Goehring LS, Matiasek K.A final diagnosis in a horse with clinical signs of encephalopathy can be challenging despite the use of extensive diagnostics. Clinical signs are often not pathognomonic and need to be interpreted in combination with (specific) laboratory results and epidemiological data of the geographical region of the origin of the case(s). Here we describe the diagnostic pathway of tick-borne encephalitis virus infection in two horses using established molecular diagnostic methods and a novel in situ hybridization technique to differentiate between regionally important/emerging diseases for central Europe...
Guzmán C, Calderón A, Oviedo T, Mattar S, Castañeda J, Rodriguez V, Moraes Figueiredo LT.Venezuelan equine encephalitis virus (VEEV) is an alphavirus that causes encephalitis with a high impact on public health in Latin America. However, only in Guatemala, Trinidad and Tobago, and Mexico have found antibodies in VEEV in bats, using immunohistochemistry, the sensitivity and specificity are improved; thus, it is better for demonstrating natural infection in bats as potential hosts. This study aimed to determine the presence of VEEV in tissues of frugivorous bats. Methods: A prospective descriptive cross-sectional study with a non-probabilistic sampling was carried out in 12 localiti...
Sijmons S, Vissani A, Tordoya MS, Muylkens B, Thiry E, Maes P, Matthijnssens J, Barrandeguy M, Van Ranst M.Equid herpesvirus 3 (EHV-3) is a member of the subfamily Alphaherpesvirinae that causes equine coital exanthema. Here, we report the first complete genome sequence of EHV-3. The 151,601-nt genome encodes 76 distinct genes like other equine alphaherpesviruses, but genetically, EHV-3 is significantly more divergent.
Eddy GA, Martin DH, Reeves WC, Johnson KM.A series of field studies using strain TC-83 attenuated Venezuelan equine encephalomyelitis vaccine in horses was made to determine the rate of seroconversions, the postvaccination viremia, and the possibility of adverse reactions to the vaccine. The rate of seroconversions varied from 50% in one study to 91 and 100% in two others. The highest level of viremia measured was 7 x 10(3) to 8 x 10(3) plaqueforming units per ml. No adverse reactions to the vaccine were observed in any horses, including 42 pregnant mares and their resulting foals.
El-Hage CM, Bamford NJ, Gilkerson JR, Lynch SE.Ross River virus (RRV) is a mosquito-borne arbovirus of the genus Alphavirus that causes disease in humans and horses in Australia. A temporal association of RRV infection in horses with clinical signs including pyrexia, malaise, and polyarthralgia has been reported, along with reduced athletic performance, often for extended periods. Despite these reports, disease due to RRV remains somewhat controversial as experimental infection of horses has resulted in obvious viraemia yet minimal signs of clinical disease. The relatively high viraemia demonstrated by horses infected with RRV has led to s...
Browning GF, Studdert MJ.The BamHI, EcoRI, and HindIII physical maps of the genomes of 14 isolates of equine herpesvirus 2 (EHV 2) were determined by Southern blot analysis using DNA fragments of a previously mapped EHV 2 strain 86/67. No two isolates had identical maps for all 3 enzymes, the number of differing cleavage sites between pairs of isolates varying from 3 to 21. Overall 75 cleavage sites were mapped, of which 40 were variable. Cleavage sites occurred throughout the genome, including within the terminal repeat regions. Additionally, fragment length polymorphisms, independent of cleavage site loss or gain, w...
Kaynarcalidan O, Oğuzoğlu TÇ.Papillomaviruses are oncogenic DNA viruses and induce hyperplastic benign lesions of both cutaneous and mucosal tissues in their various hosts, including many domestic and wild animals as well as humans. There are some Papillomavirus genotypes that can infect hosts different from their own, such as BPV 1 and BPV 2 originated from cattle, which can also infect horses and are responsible for fibroblastic tumours in horses. This review article summarizes the origin and evolution of papillomaviruses as an etiological agent in the historical process. The main focus in this review is the evaluation ...
Gutiérrez S, Thébaud G, Smith DR, Kenney JL, Weaver SC.The within-host diversity of virus populations can be drastically limited during between-host transmission, with primary infection of hosts representing a major constraint to diversity maintenance. However, there is an extreme paucity of quantitative data on the demographic changes experienced by virus populations during primary infection. Here, the multiplicity of cellular infection (MOI) and population bottlenecks were quantified during primary mosquito infection by Venezuelan equine encephalitis virus, an arbovirus causing neurological disease in humans and equids.
Guthrie AJ, Howell PG, Hedges JF, Bosman AM, Balasuriya UB, McCollum WH, Timoney PJ, MacLachlan NJ.A serological study conducted in 1995 revealed that 7 stallions at the Lipizzaner Centre, Gauteng, South Africa, were seropositive for antibody to equine arteritis virus (EAV). A Lipizzaner stallion imported into South Africa from Yugoslavia in 1981 had previously (1988) been confirmed to be an EAV carrier. Despite being placed under life-long breeding quarantine, EAV had been transmitted between stallions at the Lipizzaner Centre. Objective: To investigate the phylogenetic relationships between the strain of EAV shed in the semen of the original carrier stallion and strains recovered from the...
Solbrig MV.Borna disease (BD), caused by the neurotropic RNA virus, Borna Disease virus, is an affliction ranging from asymptomatic to fatal meningoencephalitis across naturally and experimentally infected warmblooded (mammalian and bird) species. More than 100 years after the first clinical descriptions of Borna disease in horses and studies beginning in the 1980's linking Borna disease virus to human neuropsychiatric diseases, experimentally infected rodents have been used as models for examining behavioral, neuropharmacological, and neurochemical responses to viral challenge at different stages of lif...
Dutta SK, Myrup AC.A novel, simple method of infectious center assay was developed to detect and quantitate the intracellular existence of equine herpesvirus 1 and equine herpesvirus 2 in peripheral blood mononuclear cells infected in vivo and in vitro with the viruses by cocultivation of these cells with a permissive equine cell culture. The infectious center titers were correlated with the infectious virus titers. In vivo equine herpesvirus 1-infected mononuclear cells obtained from ponies experimentally infected with the virus and equine herpesvirus 2-infected mononuclear cells obtained from selected naturall...
Back H, Berndtsson LT, Gröndahl G, Ståhl K, Pringle J, Zohari S.Equine Influenza Virus (EIV) is a major cause of respiratory disease in horses and the virus constantly undergoes antigenic drift. Here we characterize and describe the HA1 and the NA genes of H3N8 within samples obtained from outbreaks in Sweden during November-December 2011. Both clade 1 and clade 2 viruses of the Florida sublineage were identified. The index case of clade 2 was transported to Sweden from Spain through the Netherlands, whereas the clade 1 had its origin from a Swedish stud farm. The clade 1 virus was efficiently spread between training yards by unvaccinated young horses, but...
Barrera R, Torres N, Freier JE, Navarro JC, García CZ, Salas R, Vasquez C, Weaver SC.The distribution of the sylvatic subtype ID Venezuelan equine encephalitis (VEE) viruses in the lowland tropical forests of western Venezuela was investigated using remote sensing and geographic information system technologies. Landsat 5 Thematic Mapper satellite imagery was used to study the reflectance patterns of VEE endemic foci and to identify other locations with similar reflectance patterns. Enzootic VEE virus variants isolated during this study are the closest genetic relatives of the epizootic viruses that emerged in western Venezuela during 1992-1993. VEE virus surveillance was condu...
Groppelli E, Tuthill TJ, Rowlands DJ.Equine rhinitis A virus (ERAV) is genetically closely related to foot-and-mouth disease virus (FMDV), and both are now classified within the genus Aphthovirus of the family Picornaviridae. For disease security reasons, FMDV can be handled only in high-containment facilities, but these constraints do not apply to ERAV, making it an attractive alternative for the study of aphthovirus biology. Here, we show, using immunofluorescence, pharmacological agents, and dominant negative inhibitors, that ERAV entry occurs (as for FMDV) via clathrin-mediated endocytosis and acidification of early endosomes...
Hierholzer JC, Gamble WC, Quist KD, Chappell WA.Horses were immunized by a variety of inoculation procedures designed to determine the most efficient method of producing antisera to adenovirus types 25 to 31. The procedures evaluated included immunization by (i) direct intravenous (iv) injection, (ii) iv infusion, (iii) intramuscular (im) injection of virus with and without Freund's incomplete adjuvant, (iv) combined iv and im injections, and (v) combined iv infusion and im injection. The im schedule (no. 3) was superior to the others in terms of immunizing antigen and time required, and hemagglutination-inhibition (HI) and serum-neutralizi...
Moloney BJ.This overview of the equine influenza (EI) epidemic as it occurred in two Australian states, New South Wales and Queensland, in 2007 describes the functions and activities of the epidemiology teams that were engaged during the outbreak and also identifies key features of the epidemiology of EI during the outbreak.
McGuire TC, O'Rourke KI, Baszler TV, Leib SR, Brassfield AL, Davis WC.Cells infected with vaccinia viruses expressing the equine infectious anaemia virus (EIAV) gag gene (VGag) or gag plus the 5' pol encoding protease (VGag/PR) were evaluated with monoclonal antibody to a p26 capsid protein linear epitope (QEISKFLTD). Both recombinant viruses expressed Gag precursor protein (55K) whereas only VGag/PR expressed a detectable Gag-Pol fusion protein (82K) with a functional protease, shown by subviral particles containing processed p26. Horses inoculated with VGag/PR produced antibodies reactive with EIAV Gag proteins.
Laviada MD, Babín M, Dominguez J, Sánchez-Vizcaíno JM.A sandwich enzyme-linked immunsorbent assay (ELISA) for rapid detection of African horsesickness virus (AHSV) in infected spleens or cell culture supernatant was developed. This method uses two monoclonal antibodies (MAbs) which recognize two non-overlapping epitopes of the major core protein (VP7) to coat the solid phase, and one labeled with biotin as second antibody. This ELISA was evaluated for its ability to detect AHSV in infected spleens resulting in a sensitivity of 97.4% and a specificity of 100% compared with virus isolation in cell culture, and can be used for the detection of the n...
Ellis JA, Konoby C, West KH, Allan GM, Krakowka S, McNeilly F, Meehan B, Walker I.Porcine circovirus type 2 (PCV2) is a recently recognized agent that is consistently associated with postweaning multisystemic wasting disease in swine. There are conflicting data concerning the ability of this virus to infect and cause disease in other species. To determine if normal cattle, cattle affected with various illnesses, and normal horses in endemic areas of PCV2 infection in swine have had PCV2 infections, 100 randomly selected bovine sera, 100 equine sera, and 100 colostrum samples from clinically normal dairy cattle were examined for the presence of antibodies to porcine circovir...
Wood JL, Chanter N, Newton JR, Burrell MH, Dugdale D, Windsor HM, Windsor GD, Rosendal S, Townsend HG.Lower respiratory tract disease developed in a group of racehorses in training between two and six years of age. Disease was observed in 22 of 25 horses for which full records were available. Seroconversion to Mycoplasma felis was demonstrated by indirect haemagglutination assay in 19 of 22 paired sera and high titres (> or = 64) were found in convalescent sera from the three remaining horses. Evidence of respiratory viral infection was confined to seroconversions to equine herpesvirus-4 in two of the horses. Tracheal wash samples, taken from four horses with visibly increased tracheal muco...
Virmani N, Bera BC, Gulati BR, Karuppusamy S, Singh BK, Kumar Vaid R, Kumar S, Kumar R, Malik P, Khurana SK, Singh J, Manuja A, Dedar R, Gupta AK....Equine influenza is a contagious viral disease that affects all members of the family Equidae, i.e., horses, donkeys and mules. The authors describe the pattern of equine influenza outbreaks in a number of states of India from July 2008 to June 2009. The disease was first reported in June 2008 in Katra (Jammu and Kashmir) and spread to ten other states within a year. All outbreaks of equine influenza in the various states were confirmed by laboratory investigations (virus isolation and/or serological confirmation based on haemagglutination inhibition [HI] assays of paired samples) before decla...
Snyder DB, Myrup AC, Dutta SK.Pony foals, negative for detectable serum-neutralizing antibody to equine herpesvirus 1 by the standard tube-culture virus neutralization test, were experimentally infected with equine herpesvirus 1. Complement-requiring (CR) and non-complement-requiring (NCR) serum-neutralizing antibodies were evaluated in preinfection and postinfection sera by means of a complement-enhanced plaque reduction assay. Low levels of CR antibodies were found in the preinfection sera of only group II ponies. Upon infection, CR antibodies were detected by day 2 postinfection and reached peak titers between 7 and 14 ...
Wilson WC, Letchworth GJ, Jiménez C, Herrero MV, Navarro R, Paz P, Cornish TE, Smoliga G, Pauszek SJ, Dornak C, George M, Rodriguez LL.Sporadic outbreaks of vesicular stomatitis (VS) in the United States result in significant economic losses for the U.S. livestock industries because VS is a reportable disease that clinically mimics foot-and-mouth disease. Rapid and accurate differentiation of these 2 diseases is critical because their consequences and control strategies differ radically. The objective of the current study was to field validate a 1-tube multiplexed real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assay for the rapid detection of Vesicular stomatitis New Jersey virus and Vesicular st...
Sreenivasan CC, Uprety T, Reedy SE, Temeeyasen G, Hause BM, Wang D, Li F, Chambers TM.Antibodies to influenza D virus (IDV) have been detected in horses, but no evidence of disease in the field has been reported. To determine whether IDV is infectious, immunogenic, and pathogenic in horses, four 2-year-old horses seronegative for both influenza A (H3N8) and D viruses were intranasally inoculated with 6.25 × 107 TCID50/animal of D/bovine/California/0363/2019 (D/CA2019) virus, using a portable equine nebulizer system. Horses were observed daily for clinical signs including rectal temperature, nasal discharge, coughing, lung sounds, tachycardia, and tachypnea. No horses exhibited...
