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.
Lobigs M, Pavy M, Hall RA, Lobigs P, Cooper P, Komiya T, Toriniwa H, Petrovsky N.Advax is a polysaccharide-based adjuvant that potently stimulates vaccine immunogenicity without the increased reactogenicity seen with other adjuvants. This study investigated the immunogenicity of a novel Advax-adjuvanted Vero cell culture candidate vaccine against Japanese encephalitis virus (JEV) in mice and horses. The results showed that, in mice, a two-immunization, low-dose (50 ng JEV antigen) regimen with adjuvanted vaccine produced solid neutralizing immunity comparable to that elicited with live ChimeriVax-JE immunization and superior to that elicited with tenfold higher doses of a ...
Qi T, Guo W, Huang W, Dai L, Zhao L, Li H, Li X, Zhang X, Wang Y, Yan Y, He N, Xiang W.During the 2007 outbreak of equine influenza (EIV) in China, an influenza virus designated A/donkey/Xinjiang/5/2007 (donkey/Xinjiang/2007) was isolated from a symptomatic donkey in Xinjiang Uygur Autonomous Region, China. To analyze the genetic evolution of the new isolate, the hemagglutinin (HA) gene of donkey/Xinjiang/2007 was amplified and sequenced. Sequence alignment, prediction of glycosylation sites and phylogenetic analysis of the HA1 protein of donkey/Xinjiang/2007 showed most similarity to the Florida sublineage clade 2 of the American lineage of equine influenza viruses. The HA1 seq...
Maclachlan NJ, Guthrie AJ.Arthropod-transmitted viruses (Arboviruses) are important causes of disease in humans and animals, and it is proposed that climate change will increase the distribution and severity of arboviral diseases. Orbiviruses are the cause of important and apparently emerging arboviral diseases of livestock, including bluetongue virus (BTV), African horse sickness virus (AHSV), equine encephalosis virus (EEV), and epizootic hemorrhagic disease virus (EHDV) that are all transmitted by haematophagous Culicoides insects. Recent changes in the global distribution and nature of BTV infection have been espec...
Nemoto M, Tsujimura K, Yamanaka T, Kondo T, Matsumura T.Loop-mediated isothermal amplification (LAMP) is a novel method for the rapid and sensitive detection of DNA without the need for expensive equipment. In the present study, LAMP assays were developed for the specific detection of Equid herpesvirus 1 and 4 (EHV-1 and EHV-4, respectively) and for the differentiation of glycoprotein E (gE)-deleted EHV-1 (DeltagE) strain, a candidate strain for a live vaccine, from field EHV-1 strains. Specific primer sets were designed for the gC and gE genes of EHV-1 and for the gC gene of EHV-4. The analytical sensitivities of the LAMP assays were compared with...
Brum MC, Anjos BL, Nogueira CE, Amaral LA, Weiblen R, Flores EF.An outbreak of severe cutaneous disease associated with an orthopoxvirus in horses in southern Brazil is described. Fourteen Crioulo mares and foals from a husbandry farm developed papules, and vesicles progressing to proliferative and exudative lesions on the muzzle, external nares, and external and internal lips. The vesicles eroded, and the proliferative lesions eventually bled and progressed to moist crusts and scars. The clinical signs lasted approximately 6-12 days, after which the animals progressively recovered. Direct electron microscopy of skin biopsies revealed brick-shaped, 250-300...
Virmani N, Bera BC, Singh BK, Shanmugasundaram K, Gulati BR, Barua S, Vaid RK, Gupta AK, Singh RK.An outbreak of equine influenza (EI) was reported in India in June, 2008 after a gap of two decades. The outbreak started from Jammu and Kashmir (Katra), northern state of India and spread to the other parts of the country affecting equines in 11 states. The virus (H3N8) was isolated from nasal swabs obtained from clinical cases in various locations in the country including Katra (Jammu and Kashmir), Mysore (Karnataka) and Ahmedabad (Gujarat) using embryonated chicken eggs. The virus isolates were identified as H3N8 by haemagglutination inhibition (HI) test titration with standard serum and by...
Loroño-Pino MA, Farfan-Ale JA, Garcia-Rejon JE, Lin M, Rosado-Paredes E, Puerto FI, Bates A, Root JJ, Franklin AB, Sullivan HJ, Blitvich BJ.No abstract available
Cymerys J, Dzieciatkowski T, Słońska A, Bierla J, Tucholska A, Chmielewska A, Golke A, Bańbura MW.Equine herpesvirus-1 (EHV-1) infections cause significant economic losses for equine industries worldwide as a result of abortion, respiratory illness, and neurologic disease in all breeds of horses. The occurrence of abortions caused by EHV-1 has repeatedly been confirmed in Poland, but neurological manifestations of the infection have not been described yet. Also it is unknown how the infection of neurons with non-neuropathogenic strains is regulated. To further understand the virus-neuron interaction we studied two strains of EHV-1 in murine primary neuron cell cultures. Both strains were i...
Reichert E, Clase A, Bacetty A, Larsen J.The New World alphaviruses Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), and western equine encephalitis virus (WEEV) pose a significant threat to human health as the etiological agents of serious viral encephalitis through natural infection as well as through their potential use as a biological weapon. At present, there is no FDA-approved medical treatment for infection with these viruses. The Defense Threat Reduction Agency, Joint Science and Technology Office for Chemical and Biological Defense (DTRA/JSTO), is currently funding research aimed at deve...
Zoonoses and public healthDecember 23, 2009
Volume 57, Issue 3 211-219 doi: 10.1111/j.1863-2378.2009.01303.x
Calistri P, Giovannini A, Savini G, Monaco F, Bonfanti L, Ceolin C, Terregino C, Tamba M, Cordioli P, Lelli R.After 10 years, West Nile virus (WNV) re-emerged in Italy in August 2008. As on 31 December 2008, the infection affected eight Provinces in three Regions (Emilia Romagna, Veneto, Lombardy), where a total of 794 cases of WNV infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. Only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in 18 different farms. The observed case-fatality rate was 15.6% (5/32). The confirmed clinical cases ...
Van Soom A, Wrathall AE, Herrler A, Nauwynck HJ.Although the transfer of embryos is much less likely to result in disease transmission than the transport of live animals, the sanitary risks associated with embryo transfer continue to be the subject of both scientific investigations and adaptations of national and international legislation. Therefore, the implications are important for veterinary practitioners and livestock breeders. In vivo-derived and in vitro-produced embryos are widely used in cattle and embryos from other species, such as sheep, goats, pigs and horses, are also currently being transferred in fairly significant numbers. ...
Heo EJ, Lee HS, Jeoung HY, Ko HR, Kweon CH, Ko YJ.A recombinant glycoprotein (R-GP) of vesicular stomatitis New Jersey virus (VSV-NJ) was expressed in insect cells by a baculovirus system. Its utility as a diagnostic antigen in a blocking ELISA was investigated as an alternative to the current native GP extracted from VSV-NJ. With the cut-off value of 73% inhibition, the R-GP ELISA exhibited 99.1% specificity for naive sera from cattle and horses. It did not cross-react with VSV-Indiana (VSV-IN) positive sera and differentiated from foot-and-mouth disease and swine vesicular disease. Taken together, this is the first report that the R-GP has ...
Giles C, Cavanagh HM, Noble G, Vanniasinkam T.There are currently two known serotypes of equine adenovirus (EAdV), equine adenovirus type 1 (EAdV1) and equine adenovirus type 2 (EAdV2); EAdV1 is predominantly associated with upper respiratory tract infections while EAdV2 appears to have a higher association with gastrointestinal infection, however, very little is known about the prevalence of these viruses in horse populations in Australia. In this study we tested 122 serum samples obtained from horses in New South Wales, Australia, using a standard serum neutralization (SN) assay and ELISA. Ninety-seven of the 122 sera displayed had mode...
Azab W, Tsujimura K, Kato K, Arii J, Morimoto T, Kawaguchi Y, Tohya Y, Matsumura T, Akashi H.Equine herpesvirus 4 (EHV-4) is an important equine pathogen that causes respiratory tract disease among horses worldwide. A thymidine kinase (TK)-deletion mutant has been generated by using bacterial artificial chromosome (BAC) technology to investigate the role of TK in pathogenesis. Deletion of TK had virtually no effect on the growth characteristics of WA79DeltaTK in cell culture when compared to the parent virus. Also, virus titers and plaque formation were unaffected in the absence of the TK gene. The sensitivity of EHV-4 to inhibition by acyclovir (ACV) and ganciclovir (GCV) was studied...
Covaleda L, Fuller FJ, Payne SL.Equine infectious anemia virus (EIAV) infection is distinctive in that it causes a rapid onset of clinical disease relative to other retroviruses. In order to understand the interaction dynamics between EIAV and the host immune response, we explored the effects of EIAV and its S2 protein in the regulation of the cytokine and chemokine response in macrophages. EIAV infection markedly altered the expression pattern of a variety of pro-inflammatory cytokines and chemokines monitored in the study. Comparative studies in the cytokine response between EIAV(17) and EIAV(17DeltaS2) infection revealed ...
Soboll G, Hussey SB, Minke JM, Landolt GA, Hunter JS, Jagannatha S, Lunn DP.Equine influenza virus remains an important problem in horses despite extensive use of vaccination. Efficacy of equine influenza vaccination depends on the onset and duration of protective immunity, and appropriate strain specificity of the immune response. This study was designed to test the protective immunity resulting from vaccination with the North American commercial ALVAC equine influenza vaccine (RECOMBITEK Influenza, Merial, USA)(1) against challenge with American lineage influenza viruses. In experiment 1, 12 ponies were vaccinated twice, at a 35 day interval, using the ALVAC-influen...
Gauci PJ, Wu JQ, Rayner GA, Barabé ND, Nagata LP, Proll DF.DNA vaccines encoding different portions of the structural proteins of western equine encephalitis virus were tested for the efficacy of their protection in a 100% lethal mouse model of the virus. The 6K-E1 structural protein encoded by the DNA vaccine conferred complete protection against challenge with the homologous strain and limited protection against challenge with a heterologous strain.
Sentsui H, Wu D, Murakami K, Kondo T, Matsumura T.Recombinant equine interferon-gamma (reIFN-gamma) was prepared using a baculovirus expression system and its antiviral activity was investigated using several equine viruses. The reIFN-gamma suppressed the replication of all equine viruses used in the present experiment in horse cell cultures, but did not affect the growth of host cells at concentrations of less than 1000 u/ml. A strong antiviral effect was observed, especially against RNA viruses. Equine picornavirus, equine rhinovirus and equine arteritis virus could not be propagated at all in 100 u/ml reIFN-gamma when 100 TCID(50) of infec...
Pusterla N, Hussey SB, Mapes S, Leutenegger CM, Madigan JE, Ferraro GL, Wilson WD, Lunn DP.The objective of the current study was to compare the performance of 4 methods to quantify Equid herpesvirus 1 (EHV-1) by real-time polymerase chain reaction (PCR) in nasal secretions from experimentally and naturally infected horses. Nasal secretions were collected on the challenge day and daily thereafter for 13 days from 4 experimentally infected horses. Additional nasal swabs were collected from 30 horses with clinical signs consistent with natural EHV-1 infection. Absolute quantitation of EHV-1 target molecules was performed using standard curves for EHV-1 and equine glyceraldehyde-3-phos...
Fine DL, Jenkins E, Martin SS, Glass P, Parker MD, Grimm B.A multisystem approach was used to assess the efficiency of several methods for inactivation of Venezuelan equine encephalitis virus (VEEV) vaccine candidates. A combination of diverse assays (plaque, in vitro cytopathology and mouse neurovirulence) was used to verify virus inactivation, along with the use of a specific ELISA to measure retention of VEEV envelope glycoprotein epitopes in the development of several inactivated VEEV candidate vaccines derived from an attenuated strain of VEEV (V3526). Incubation of V3526 aliquots at temperatures in excess of 64 degrees C for periods >30 min i...
Brosnahan MM, Damiani A, van de Walle G, Erb H, Perkins GA, Osterrieder N.Available vaccines fail to induce lasting and protective immunity to equine herpesvirus 1 (EHV-1) associated diseases. RNA interference is a novel approach showing promise for therapeutic use in outbreak situations. This study examined the effect of small interfering RNA (siRNA) on clinical signs as well as the presence of live virus and viral DNA in nasal secretions and peripheral blood mononuclear cells (PBMCs) in horses experimentally infected with EHV-1. siRNA targeting two EHV-1 genes (glycoprotein B and the origin binding protein) was administered 12h before and 12h after intranasal infe...
Dzieciatkowski T, Przybylski M, Cymerys J, Turowska A, Chmielewska A, Tucholska A, Banbura MW.Equine herpesvirus type 1 (EHV-1) is one of the major viral agents causing diseases in horses common worldwide. A variety of techniques, including PCR, have been used to diagnose EHV-1 infections. In this paper, an attempt of real-time PCR has been described, which uses specific fluorochrome-labeled TaqMan probes for detection of viral DNA. This method does not require post-amplification manipulations, thereby reducing the risk of cross-contamination. The assay was sensitive enough to detect EHV-1 sequences in different clinical samples, as well in mice neuronal cell cultures. The technique wa...
Arrigo NC, Adams AP, Weaver SC.The eastern equine encephalitis (EEE) complex consists of four distinct genetic lineages: one that circulates in North America (NA EEEV) and the Caribbean and three that circulate in Central and South America (SA EEEV). Differences in their geographic, pathogenic, and epidemiologic profiles prompted evaluation of their genetic diversity and evolutionary histories. The structural polyprotein open reading frames of all available SA EEEV and recent NA EEEV isolates were sequenced and used in evolutionary and phylogenetic analyses. The nucleotide substitution rate per year for SA EEEV (1.2 x 10(-4...
Bryant NA, Paillot R, Rash AS, Medcalf E, Montesso F, Ross J, Watson J, Jeggo M, Lewis NS, Newton JR, Elton DM.During 2007, large outbreaks of equine influenza (EI) caused by Florida sublineage Clade 1 viruses affected horse populations in Japan and Australia. The likely protection that would be provided by two modern vaccines commercially available in the European Union (an ISCOM-based and a canarypox-based vaccine) at the time of the outbreaks was determined. Vaccinated ponies were challenged with a representative outbreak isolate (A/eq/Sydney/2888-8/07) and levels of protection were compared.A group of ponies infected 18 months previously with a phylogenetically-related isolate from 2003 (A/eq/South...
Gryspeerdt AC, Vandekerckhove AP, Garré B, Barbé F, Van de Walle GR, Nauwynck HJ.Equine herpesvirus 1 (EHV1) replicates in the respiratory tract of horses, after which infected leukocytes transport virus throughout the body, resulting in abortion or nervous system disorders. Two EHV1 strains circulate in the field: neurovirulent and non-neurovirulent. To investigate differences in replication in the upper respiratory tract (URT), an experimental inoculation study in ponies was performed with both strains. Two groups of six ponies, were inoculated intranasally with 10(6.5) TCID(50) of either strain. Clinical signs, nasal shedding and viremia were evaluated. At early time po...
Gaede W, Reckling KF, Schliephake A, Missal D, Hotzel H, Sachse K.At a stud farm of Trakehner horses, all 33 foals of a birth cohort developed conjunctivitis and serous to muco-purulent rhinitis, and 7 older horses showed recurrent signs of conjunctivitis. Examination of nasal and conjunctival swabs by bacterial and cell culture, as well as real-time PCR, ArrayTube microarray analysis and DNA sequencing led to the identification of Chlamydophila (C.) caviae (first description in horses) and Streptococcus (S.) equi subsp. zooepidemicus. We presume a synergistic effect associated with these two agents by hypothesising that primary lesions were set by C. caviae...
Lu Z, Chambers TM, Boliar S, Branscum AJ, Sturgill TL, Timoney PJ, Reedy SE, Tudor LR, Dubovi EJ, Vickers ML, Sells S, Balasuriya UB.The objective of this study was to develop and evaluate new TaqMan real-time reverse transcription-PCR (rRT-PCR) assays by the use of the minor groove binding probe to detect a wide range of equine influenza virus (EIV) strains comprising both subtypes of the virus (H3N8 and H7N7). A total of eight rRT-PCR assays were developed, targeting the nucleoprotein (NP), matrix (M), and hemagglutinin (HA) genes of the two EIV subtypes. None of the eight assays cross-reacted with any of the other known equine respiratory viruses. Three rRT-PCR assays (EqFlu NP, M, and HA3) which can detect strains of th...
Craigo JK, Barnes S, Zhang B, Cook SJ, Howe L, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV), a lentivirus that infects horses, has been utilized as an animal model for the study of HIV. Furthermore, the disease associated with the equine lentivirus poses a significant challenge to veterinary medicine around the world. As with all lentiviruses, EIAV has been shown to have a high propensity for genomic sequence and antigenic variation, especially in its envelope (Env) proteins. Recent studies have demonstrated Env variation to be a major determinant of vaccine efficacy, emphasizing the importance of defining natural variation among field isolates o...
Sergeant ES, Kirkland PD, Cowled BD.During the Australian epidemic of equine influenza in 2007, tens of thousands of horses were infected. From the resulting field data, 475 known infected and 1323 uninfected horses were identified to allow a post outbreak evaluation of the performance of the commonly used bELISA for influenza A under field conditions. A variety of techniques, such as ROC plots, area under the curve and hypothesis testing were used to assess the overall performance of the test. The test was deemed to be accurate (area under curve=0.993+/-0.003 standard error) and significantly informative (z=-32.0; p or =50) wer...
Konishi E.The literature on natural infections with Japanese encephalitis virus in Japan and subclinical:clinical infection rates was summarized. To detect natural infections, conventional serologic methods were used in the past, while nonstructural 1 protein-based methods have been used recently. Annual infection rates in humans and horses indicated the status of natural virus activity in Japan.
Kirisawa R, Toishi Y, Akamatsu A, Soejima K, Miyashita T, Tsunoda N.In the spring of 2015, two stallions reared in Farms A and B in Hokkaido in Japan showed symptoms of equine coital exanthema. Equine herpesvirus 3 (EHV-3) was isolated from penis swab samples of both stallions, and the isolates from each stallion in Farms A and B were designated as SS-1 and YS-1 strains, respectively. BamHI restriction profiles of SS-1 and Japanese reference strain Iwate-1 were indistinguishable, but the BamHI-A fragment of YS-1 was larger than those of SS-1 and Iwate-1 by 1.9 kbp because of the lack of two BamHI sites. Nucleotide sequence analyses of glycoprotein G (gG), gB, ...
Gaudaire D, Lecouturier F, Ponçon N, Morilland E, Laugier C, Zientara S, Hans A.In 2009, a major outbreak of equine infectious anaemia (EIA) was reported in the south-east of France. This outbreak affected three premises located in the Var region where the index case, a 10-year-old mare that exhibited clinical signs consistent with EIA, occurred at a riding school. Overall, more than 250 horses were tested for EIAV (equine infectious anaemia virus) antibodies, using agar gel immunodiffusion test, and 16 horses were positive in three different holdings. Epidemiological survey confirmed that the three premises were related through the purchase/sale of horses and the use of ...
Sundquist B, Lövgren K, Morein B.A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Borges IA, Reynolds MG, McCollum AM, Figueiredo PO, Ambrosio LLD, Vieira FN, Costa GB, Matos ACD, de Andrade Almeida VM, Ferreira PCP, Lobato ZIP....Since 1999 (VACV) outbreaks involving bovines and humans have been reported in Brazil; this zoonosis is known as Bovine Vaccinia (BV) and is mainly an occupational disease of milkers. It was only in 2008 (and then again in 2011 and 2014) however, that VACV was found causing natural infections in Brazilian equids. These reports involved only equids, no infected humans or bovines were identified, and the sources of infections remain unknown up to date. The peculiarities of Equine Vaccinia outbreaks (e.g., absence of human infection), the frequently shared environments, and fomites by equids and...
Swayze RD, Bhogal HS, Barabé ND, McLaws LJ, Wu JQ.Western equine encephalitis virus (WEEV) is a mosquito-borne RNA virus which causes lethal infection in humans and equines. There are no commercial vaccines or anti-WEEV drugs available for humans. We used replication-defective, human adenovirus serotype-5 (HAd5) as a delivery vector for developing WEEV vaccine. Our previous study found delivery of both E1 and E2 envelope proteins of WEEV by HAd5 vector offers complete protection against lethal challenge of WEEV. In this paper, we constructed a HAd5-vectored E1 vaccine, Ad5-E1. Mice given single-dose vaccination of Ad5-E1 were completely prote...
Van Eeden C, Zaayman D, Venter M.Recently Shuni virus (SHUV) has been identified in clinical cases of neurological disease in horses in South Africa. Being that it was one of the less recognized orthobunyaviruses, with limited clinical descriptions of disease dating back to the 1960s and 1970s, SHUV-specific assays were never developed. In this study, the development of a nested real-time PCR assay is described for the detection of SHUV by means of melt-curve analysis using fluorescence resonance energy transfer (FRET) probe technology. The assay was validated against previously positive clinical specimens and a dilution seri...
Metz MBC, Olufemi OT, Daly JM, Barba M.There is some evidence that West Nile virus (WNV), which causes encephalomyelitis in equids, is an emerging disease in Europe. The aim of this study was to perform a systematic review and meta-analysis to analyse seroprevalence studies of WNV in equids in European countries between 2001 and 2018. Two electronic databases, PubMed and Scopus, were searched for relevant publications published from 2001 to 2018 using predetermined keywords. A total of 1,484 papers were initially found. After applying the eligibility criteria, 39 papers were finally included in the systematic review. Analysis of 28...
Koch C, Ramsauer AS, Drögemüller M, Ackermann M, Gerber V, Tobler K.Several attempts have been made to categorize equid- and bovid-specific bovine papillomavirus 1 (BPV1) isolates based on sequence tags. This study includes newly determined sequence information from 33 BPV1 isolates of equine, asinine and bovine origin and investigates sequence bias due to host species. Twenty of the viral genomes were sequenced over their entire length and a further thirteen were sequenced, including flanking sequences, at two specific sites, the LCR and the E5 ORF. Alignment and analyses of the sequences did not reveal statistically significant site differences between the s...
Abrahão JS, de Souza Trindade G, Pereira-Oliveira G, de Oliveira Figueiredo P, Costa G, Moreira Franco-Luiz AP, Lopes Assis F, Bretas de Oliveira D....In August 2014, an outbreak of oral exanthematous disease in equids was reported in Brazil, affecting 11 donkeys and 3 mules. Objective: To investigate if Vaccinia virus (VACV) was the aetiological agent in this outbreak. Methods: Investigation of clinical cases using serological, molecular and phylogenetic approaches. Methods: To analyse the presence of neutralising antibodies against VACV, samples were submitted in triplicate to a plaque-reduction neutralisation test (PRNT ). On the basis of previous studies which detected VACV DNA in sera, we submitted extracted DNA samples to different pol...
Dunowska M, Gopakumar G, Perrott MR, Kendall AT, Waropastrakul S, Hartley CA, Carslake HB.Infection with equid herpesvirus 1 (EHV-1) may be asymptomatic, or may result in respiratory disease, abortion, neonatal death, or neurological disease. The aim of this study was to estimate the prevalence of EHV-1 infection, including differentiation between genotypes with aspartic acid (D) and asparagine (N) at position 752 of the DNA polymerase sequence, within a selected population of New Zealand horses. The second aim was to determine the predictive value of serology for detection of latently infected horses. Retropharyngeal lymph nodes (RLN) and trigeminal ganglia (TG) were dissected fro...
Tang YD, Zhang X, Na L, Wang XF, Fu LH, Zhu CH, Wang X, Zhou JH.Equine infectious anemia virus (EIAV) is a member of the genus Lentivirus of the family Retroviridae. Horses are the most susceptible equids to EIAV infection and are therefore the primary hosts of this virus. In contrast, infected donkeys do not develop clinically active equine infectious anemia (EIA). This phenomenon is similar to what has been observed with HIV-1, which fails to induce AIDS in non-human primates. Interestingly, Shen et al. developed a donkey-tropic pathogenic virus strain (EIAVDV117, DV117) by serially passaging a horse-tropic pathogenic strain, EIAVLN40 (LN40), in donkeys....
Yamanaka T, Nemoto M, Bannai H, Tsujimura K, Matsumura T, Kokado H, Gildea S, Cullinane A.Equine influenza (EI) vaccine has been widely used. However, the causative EI virus (H3N8) undergoes continuous antigenic drift, and the vaccine strains must be periodically reviewed and if necessary, updated to maintain vaccine efficacy against circulating viruses. In 2016, the Japanese vaccine was updated by replacing the old viruses with the Florida sub-lineage Clade (Fc) 2 virus, A/equine/Yokohama/aq13/2010 (Y10). We investigated the virus neutralization (VN) antibody response to Fc2 viruses currently circulating in Europe, after booster or primary immunization with the new vaccine. These ...
Anagha G, Gulati BR, Riyesh T, Virmani N.Equine herpesvirus 1 (EHV1) is a common pathogen of horses that causes upper respiratory tract disease, abortion, neonatal death and neurological disease. The neurological form of disease is called equine herpesvirus myeloencephalopathy (EHM). During the past decade, the incidence of EHM has been on the rise in Europe, North America, Australia and Asia. Some EHV1 isolates causing EHM exhibit a single-nucleotide polymorphism (SNP) in the DNA polymerase gene (ORF30) at position 2254 (A to G). Further, based on polymorphism in the ORF68, EHV1 isolates have been classified into different groups. T...
Agius CT, Nagesha HS, Studdert MJ.A new equine herpesvirus, provisionally designated equine herpesvirus 5 (EHV5; Browning and Studdert (1987) J. Gen. Virol. 68, 1441-1447), was examined for the degree of genomic difference from equine herpesvirus 2 (EHV2) by Southern hybridizations. EHV5 and EHV2 whole genomic DNA probes were highly specific for homologous DNA only, indicating that significant genomic difference exists between the two viruses. Restriction endonuclease analysis of EHV5 strain 2-141 (EHV5.2-141) revealed that the genome is 179 kb and exists as a single isomer. Clones representing 82% of the genome were obtained ...
Peters-Kennedy J, Lange CE, Rine SL, Hackett RP.Equus caballus papillomavirus 8, a recently discovered virus, has been reported to cause generalised papillomavirus in horses. Objective: To describe a case in which multiple viral plaques, viral papillomas, squamous cell carcinoma (SCC) in situ and invasive squamous cell carcinoma (ISCC) were associated with EcPV8 in a horse. Methods: Case report. Methods: A 16-year-old mixed breed horse presented with dozens of raised crusted papular to nodular lesions over a course of 4 years. Masses had been surgically excised four times and cisplatin beads and emulsion were implanted on three different ...
Müller K, König M, Thiel HJ.The tick-borne encephalitis (TBE), also known as early summer meningo-encephalitis, is a geographically limited virus infection transmitted mainly by ticks. The importance of TBE is largely underestimated. The causative agent TBE-Virus (TBEV) is grouped into the genus Flavivirus of the virus family Flaviviridae. Clinical disease including fatal outcomes has been described for men and dogs. With regard to horses only a limited number of case reports is available. In a study performed at the Institute of Virology, Justus-Liebig-University Giessen serum samples from the German endemic region of M...
Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize cur...
Bannai H, Takahashi Y, Ohmura H, Ebisuda Y, Mukai K, Kambayashi Y, Nemoto M, Tsujimura K, Ohta M, Raidal S, Padalino B.This study evaluated the effects of 12-hour transportation on immune responses to equine herpesvirus type 1 (EHV-1) and type 4 (EHV-4). Possible replication of EHV-1 and EHV-4 was monitored by real-time PCR of nasal swabs and peripheral blood mononuclear cells (PBMCs), and changes in systemic and mucosal antibodies were investigated. Six healthy Thoroughbreds with transport experience were transported in commercial trucks, repeating the same three-hour route four times. Blood samples for cortisol measurement were taken before departure and every three hours. Nasal swabs, PBMCs, nasal wash and ...
Lonning SM, Zhang W, Leib SR, McGuire TC.Cytotoxic T lymphocytes (CTL) appear to be critical in resolving or reducing the severity of lentivirus infections. Retroviral vectors expressing the Gag/Pr or SU protein of the lentivirus equine infectious anemia virus (EIAV) were constructed and used to evaluate EIAV-specific CTL responses in horses. Three promoters, cytomegalovirus, simian virus SV40, and Moloney murine sarcoma virus (MoMSV) long terminal repeat (LTR), were used, and there was considerable variation in their ability to direct expression of Gag/Pr and SU. Vectors expressing EIAV proteins under the direction of MoMSV LTR and ...
Little PB, Thorsen J, Moore W, Weninger N.Powassan virus strain M794, a member of the Flavivirus genus known to infect man and animals in Canada, was inoculated intracerebrally into rabbits and horses. No clinical signs were observed in rabbits, but widespread encephalitis resulted, characterized by lymphoid perivascular cuffing, lymphocytic meningitis, and lymphocytic choroiditis. In horses, eight days after inoculation, prominent neurological signs occurred and lesions were those of non-suppurative encephalomyelitis, neuronal necrosis, and focal parenchymal necrosis. The virus could not be reisolated from the rabbit or horse brains....
Tsujimura K, Yamanaka T, Kondo T, Fukushi H, Matsumura T.To develop a live vaccine for equine herpesvirus type 1 (EHV-1), two EHV-1 mutants containing no heterogeneous DNA, DeltagI and DeltagE, were constructed with deletions in the open reading frame of either glycoprotein I (gI) or E (gE), respectively. In equine cell culture, deletion mutants formed smaller plaques than the parental and revertant viruses, but the one-step growth patterns of the deletion mutants and the parental strain were approximately the same. These results suggest that both gI and gE contribute to the ability of EHV-1 to spread directly from cell-to-cell, but that these glyco...
Bannai H, Nemoto M, Tsujimura K, Yamanaka T, Kondo T, Matsumura T.Virus-neutralizing (VN) testing is essential for evaluating virus-specific immunity in equine herpesvirus type-1 (EHV-1) infection. We developed a focus-reduction neutralization test (FRNT) for EHV-1 using 96-well plates for faster large-scale testing with sufficient sensitivity. We used an overlay medium containing Avicel (FMC Biopolymer), a microcrystalline cellulose with lower viscosity than the methylcellulose. The foci were visualized by immuno-staining with anti-EHV-1 gp14 monoclonal antibody. The FRNT successfully detected seroconversion in horses experimentally infected with EHV-1 (n =...
McGuire TC, Zhang W, Hines MT, Henney PJ, Byrne KM.Horses with equine infectious anemia virus (EIAV) have episodes of viremia and disease; however, most eventually become inapparent carriers. A possible mechanism of control is cytotoxic T lymphocytes (CTL). To evaluate CTL in inapparent carriers with low viral loads, peripheral blood mononuclear cells (PBMC) were stimulated in vitro with autologous EIAV-infected PBMC and human IL-2 to detect memory CTL (CTLm). In initial studies, three carriers had CTLm and one of these had low-level effector CTL (CTLe). The CTLm were restricted by equine lymphocyte alloantigen-A (ELA-A) locus encoded MHC clas...
Hurst EW.The virus of equine encephalomyelitis (eastern strain) evokes in the horse, calf, sheep and dog an unusually intense encephalomyelitis characterized by acute primary degeneration of nerve cells, the appearance in neurons of the brain stem and elsewhere of nuclear inclusions resembling those in Borna disease and poliomyelitis, polymorphonuclear infiltration in the nervous tissues with early microglial proliferation, and perivascular cuffing with mononuclears and polymorphonuclears in varying proportions. The grey matter is affected more than the white. Lesions may be less marked in the striatum...
Gonzalez-Obando J, Forero JE, Zuluaga-Cabrera AM, Ruiz-Saenz J.Equine influenza is a highly contagious disease caused by the H3N8 equine influenza virus (EIV), which is endemically distributed throughout the world. It infects equids, and interspecies transmission to dogs has been reported. The H3N8 Florida lineage, which is divided into clades 1 and 2, is the most representative lineage in the Americas. The EIV infects the respiratory system, affecting the ciliated epithelial cells and preventing the elimination of foreign bodies and substances. Certain factors related to the disease, such as an outdated vaccination plan, age, training, and close contact ...
Blunden AS, Smith KC, Whitwell KE, Dunn KA.A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto u...
Claessen C, Favoreel H, Ma G, Osterrieder N, De Schauwer C, Piepers S, Van de Walle GR.Equid herpesvirus 1 (EHV1) is an ubiquitous alphaherpesvirus that can cause respiratory disease, abortion and central nervous disorders. EHV1 is known to infect a variety of different cell types in vitro, but its tropism for cultured primary equine mesenchymal stem cells (MSC) has never been explored. We report that equine MSC were highly permissive for EHV1 and supported lytic replication of the virus in vitro. Interestingly, we observed that an infection of MSC with EHV1 resulted in a consistent downregulation of cell surface molecules CD29 (β1-integrin), CD105 (endoglin), major histocompat...
Schwartz EJ, Vaidya NK, Dorman KS, Carpenter S, Mealey RH.Understanding the dynamics of acute viral infection is crucial for developing strategies to prevent and control infection. In this study, lentiviral dynamics in a host without adaptive immunity were examined in order to determine kinetic parameters of infection and quantify the effect of neutralizing antibodies in preventing infection, using mathematical modeling of data from equine infectious anemia virus (EIAV) infection of horses with severe combined immunodeficiency (SCID). Estimated parameters were used to calculate the basic reproductive number and virus doubling time and found that the ...
Pavulraj S, Virmani N, Bera BC, Joshi A, Anand T, Virmani M, Singh R, Singh RK, Tripathi BN.Equine influenza viruses (EIVs) are responsible for acute contagious respiratory infection in equines and the disease remains a major threat for equine population throughout the world despite vaccination strategies in place. The present study was aimed to assess the suitability of BALB/c mice as a potential small animal model for preliminary screening of EI vaccine candidates. For this, we evaluated the immunogenicity and protective efficacy of an inactivated EIV (H3N8) vaccine in BALB/c mouse model after challenge with homologous H3N8 virus (Clade 2 virus, Florida sublineage) through serology...
Webster RG, Thomas TL.A new H3N8 equine influenza virus [A/Equine/Jilin/1/89 (Eq/Jilin)] appeared in Northeastern China in 1989 and caused high mortality in horses; the available evidence indicates that it has not yet spread outside this region of the world. Serological analysis with postinfection ferret sera in haemagglutination inhibition (HI) tests confirmed that Eq/Jilin is antigenically distinct from H3N8 equine influenza viruses isolated between 1963 and 1991 and also showed that a current equine influenza virus [A/Equine/Alaska/1/91 (H3N8)] had undergone antigenic drift. In the present study we determine if ...
