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.
Karamendin K, Abishov A, Kydyrmanov A, Akhmetzhanova M.In 2011, there was an outbreak of a disease with mass abortions among horses in southeastern Kazakhstan. The AK-2011 strain was isolated from an aborted fetus and subsequently identified as equid alphaherpesvirus 1. Here, we describe the nearly complete genome sequence of the AK-2011 strain, attenuated for vaccine development.
de Almeida Campos AC, Cicolo S, de Oliveira CM, Molina CV, Navas-Suárez PE, Dos Santos TP, da Silveira VB, Barbosa CM, Baccarin RYA, Durigon EL....No abstract available
Pusterla N, Barnum S, Lawton K, Wademan C, Corbin R, Hodzic E.Contemporary data on equine herpesvirus-1 (EHV-1) genotype (non-neuropathogenic or N, neuropathogenic or D and new variant or H) in clinically diseased equids is important in order to determine the frequency of these genotypes and their association with disease expression. A total of 297 EHV-1 qPCR-positive swabs collected from 2019 to 2022 from horses with respiratory disease (EHV-1), neurological disease (equine herpesvirus-1 myeloencephalopathy [EHM]) and abortion were tested for the three different EHV-1 genotypes (N, D and H) using qPCR allelic discrimination assays. All submissions origi...
Sewgobind S, Johnson N, Mansfield KL.Japanese encephalitis (JE) is an infection that occurs predominantly in Asia and the Pacific Islands. It is transmitted by mosquito bites, with the main vector being Culex tritaeniorhynchus, and is maintained in enzootic cycles involving pigs, wild birds and mosquitoes. JE is caused by infection with Japanese encephalitis virus (JEV), a zoonotic pathogen that also causes disease in mammals such as pigs and horses. In humans, most symptoms are mild or flu-like but can progress to encephalitis. Pigs are considered amplification hosts, and sows may have gestational complications. Horses may exhib...
Fukushi N, Badr Y, Fukushi H.Equine herpesvirus type 1 (EHV-1) UL11 is a 74-amino-acid (aa) protein encoded by ORF51. UL11 is modified by acylation including myristoylation and palmitoylation. Myristoylation of EHV-1 UL11 is assumed to occur on the N-terminal glycine, while palmitoylation is assumed to occur on the seventh and ninth cysteines. ORF51, which encodes the first 24 aa, overlaps ORF50 encoding UL12. We previously demonstrated that UL11 was essential for EHV-1 replication in cultured cells and that UL11 was localized at the Golgi apparatus where herpesviruses obtain their final envelope. It is unclear whether th...
Cantón GJ, Navarro MA, Asin J, Chu P, Henderson EE, Mete A, Uzal FA.Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California-Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were estab...
Alshahrani SH, Alameri AA, Kahar F, Alexis Ramírez-Coronel A, Fadhel Obaid R, Alsaikhan F, Zabibah RS, Qasim QA, Altalbawy FMA, Fakri Mustafa Y....Recently in vivo and in vitro studies have provided evidence establishing the significance of microRNAs (miRNAs) in both physiological and pathological conditions. In this regard, the role of miRNA-128 (miR-128) in health and diseases has been found, and its critical regulatory role in the context of some viral diseases has been recently identified. For instance, it has been found that miR-128 can serve as an antiviral mediator and significantly limit the replication and dissemination of human immunodeficiency virus type 1 (HIV-1). Besides, it has been noted that poliovirus receptor-related 4 ...
Ogorek TJ, Golden JE.Venezuelan, western, and eastern equine encephalitic alphaviruses (VEEV, WEEV, and EEEV, respectively) are arboviruses that are highly pathogenic to equines and cause significant harm to infected humans. Currently, human alphavirus infection and the resulting diseases caused by them are unmitigated due to the absence of approved vaccines or therapeutics for general use. These circumstances, combined with the unpredictability of outbreaks-as exemplified by a 2019 EEE surge in the United States that claimed 19 patient lives-emphasize the risks posed by these viruses, especially for aerosolized V...
Chappell DE, Barnett DC, James K, Craig B, Bain F, Gaughan E, Schneider C, Vaala W, Barnum SM, Pusterla N.A voluntary upper respiratory biosurveillance program in the USA received 9740 nasal swab submissions during the years 2008-2021 from 333 veterinarians and veterinary clinics. The nasal swabs were submitted for qPCR testing for six common upper respiratory pathogens:equine influenza virus (EIV), equine herpesvirus-1 (EHV-1), equine herpesvirus-4 (EHV-4), subspecies (), equine rhinitis A virus (ERAV), and equine rhinitis B virus (ERBV). Additional testing was performed for equine gamma herpesvirus-2 (EHV-2) and equine gamma herpesvirus-5 (EHV-5) and the results are reported. Basic frequency s...
Miglinci L, Reicher P, Nell B, Koch M, Jindra C, Brandt S.Squamous cell carcinoma (SCC) seriously compromises the health and welfare of affected horses. Although robust evidence points to equine papillomavirus type 2 (EcPV2) causing genital lesions, the etiopathogenesis of equine SCC is still poorly understood. We screened a series of SCCs from the head-and-neck (HN), (peri-)ocular and genital region, and site-matched controls for the presence of EcPV2-5 and herpesvirus DNA using type-specific EcPV PCR, and consensus nested herpesvirus PCR followed by sequencing. EcPV2 DNA was detected in 45.5% of HN lesions, 8.3% of (peri-)ocular SCCs, and 100% of g...
Munday JS, Grant K, Orbell G, Vaatstra BL.A 6-year-old Thoroughbred mare developed multiple flat plaques, < 1 cm in diameter, on the left front fetlock. These were treated topically using 5-fluorouracil and resolved after 4 weeks. However, additional similar plaques developed on the left front pastern 5 months later. These lesions resolved within 3 months without treatment. Unassigned: One plaque that developed initially and one plaque that developed later were examined histologically. Both consisted of well-demarcated foci of moderate epidermal hyperplasia. Scattered throughout both plaques were cells showing evidence of papillo...
Laabassi F, Dheilly N, Beck C, Amaral R, Gonzalez G, Gaudaire D, Madeline A, Lecouturier F, Lecollinet S, Zientara S, Hans A, Valle-Casuso JC.In order to determine the prevalence of equine infectious anemia virus (EIAV), Usutu virus (USUV), and West Nile virus (WNV) in eastern Algerian drylands, 340 sera from distinct equids have been collected from 2015 to 2017. Serological analysis for the presence of antibodies against EIAV and flaviviruses was performed using commercially available ELISAs. Sera detected positive, doubtful, or negative close to the doubtful threshold in flavivirus ELISA were tested by the virus neutralization test (VNT), using WNV and USUV strains. The prevalence of WNV antibodies with ELISA was 11.47% (39/340) a...
Ochi A, Bannai H, Aonuma H, Kanuka H, Uchida-Fujii E, Kinoshita Y, Ohta M, Kambayashi Y, Tsujimura K, Ueno T, Nemoto M.Mosquitoes and EDTA-treated blood samples from febrile racehorses were investigated for Getah virus infection from 2016 to 2019 at the Miho Training Center, where several outbreaks of Getah virus have occurred. We collected 5557 mosquitoes and 331 blood samples from febrile horses in this study. The most frequently captured mosquito species was Culex tritaeniorhynchus (51.9%), followed by Aedes vexans nipponii (14.2%) and Anopheles sinensis (11.2%). Getah virus was detected in mosquitoes (Aedes vexans nipponii) in 2016 (strain 16-0810-26) but not in 2017-2019. Six of 74 febrile horses in 2016 ...
Bannai H, Kambayashi Y, Nemoto M, Ohta M, Tsujimura K.The immune response and protective efficacy of a modified equid alphaherpesvirus 1 (EHV-1) vaccine administered by two different routes were tested in horses. Horses that received intramuscular (IM) priming and an intranasal (IN) booster with a 28-day interval (IM-IN group [n = 6]), IN priming and IM booster (IN-IM group [n = 5]), or no vaccination (control group [n = 6]) were challenged with EHV-1 strain 10-I-224 28 days after the second vaccination. Both vaccinated groups had significantly higher serum virus-neutralizing titers than the control group, with increased levels of ser...
Balena V, Pradhan SS, Bera BC, Anand T, Sansanwal R, Khetmalis R, Madhwal A, Bernela M, Supriya K, Pavulraj S, Tripathi BN, Virmani N.Equid alphaherpesvirus 1 (EHV-1) infection causes significant health problems in equines. The EHV-1 infection leads to abortion storm in mares, respiratory disease and myeloencephalopathy. Despite the wide use of vaccines, the outbreaks of EHV-1 infections keep occurring globally, suggesting the need for the development of improved vaccines. Gene deletion attenuated mutant viruses could be a good candidate for the development of modified live vaccines. Here, we report the generation of mutant EHV-1 by deleting virulence (glycoprotein E & internal repeat 6; IR6) and immune evasive (pUL43 &a...
Musa-Gobe R, Omeiza G, Nafarnda W, Adamu A.West Nile virus (WNV) is an emerging arbovirus which affects humans and horses. A cross sectional study was carried out on 106 local horses in Kaduna and 78 domestic chickens in Federal Capital Territory. A total of 184 sera were screened for West Nile virus anti Pr‑E antibodies using ID Screen® West Nile competitive enzyme linked immunosorbent assay. For the horses, an overall prevalence of 92.45% was recorded while domestic chickens had a preponderance of 7.69%. From our study, there was a statistical significant difference between the occurrences of WNV in stallions than mares with p <...
Vandoorn E, Stadejek W, Leroux-Roels I, Leroux-Roels G, Parys A, Van Reeth K.Influenza A viruses (IAVs) of subtype H3 that infect humans are antigenically divergent from those of birds, horses, and swine. Human immunity against these viruses might be limited, implying potential pandemic risk. To determine human risk, we selected 4 avian, 1 equine, and 3 swine IAVs representing major H3 lineages. We tested serum collected during 2017-2018 from 286 persons in Belgium for hemagglutination inhibiting antibodies and virus neutralizing antibodies against those animal-origin IAVs and tested replication in human airway epithelia. Seroprevalence rates for circulating IAVs from ...
Barbosa JD, Lins AMC, Bomjardim HDA, Silveira NDSES, Barbosa CC, Beuttemmuller EA, Brito MF, Salvarani FM.An investigative and epidemiological study was carried out for equine herpesvirus type 1 (HVE-1) in 10 outbreaks of neurological disease from different farms in the state of Pará, Brazil. 25 horses were studied: six male and 19 females, aged between one and 13 years. A necropsy of six horses was performed, and the others recovered either with or without treatment (T1-vitamin B1 + dexamentasone; T2-vitamin B1 + flunixim meglumine). Animals that received treatment recovered after eight days. The main clinical signs observed were motor incoordination, progressive paresis, thoracic and/or pelvic ...
Carnet F, Paillot R, Fortier C, Hue ES, Briot L, de Geoffroy F, Vidalain PO, Pronost S.Equine influenza virus (EIV) is responsible for recurring outbreaks that are detrimental to the equine industry. Vaccination is key for prevention, but the effectiveness and duration of protection provided by existing vaccines is often insufficient. In order to improve vaccine efficacy, we evaluated the benefit of immune stimulation with inactivated Parapoxvirus ovis (iPPVO) on the antibody response induced by a vaccine boost against EIV. A whole inactivated ISCOMatrix-adjuvanted equine influenza vaccine was administered alone ( = 10) or combined with iPPVO injections at D0, D2 and D4 post vac...
Fukushi N, Fukushi H.Equine herpesvirus type 1 (EHV-1) is a devastating pathogen of horses, their natural hosts, and causes fatal encephalitis in non-natural hosts. We previously demonstrated that acylation of the tegument protein UL11 is required for viral replication in cultured cells. We created a mutant virus (EHV-1 UL12 trunc UL11 G2AC7AC9A), in which glycyl and cysteinyl residues at positions 2, 7 and 9 of UL11 that are normally acylated were replaced with alanyl residues. This virus, designated the 2/7/9 mutant, has a limited-replication cycle (LRC), in which replication stops after just a few cycles. Here,...
Ou J, Li J, Wang X, Zhong L, Xu L, Xie J, Lu G, Li S.The family comprises many major viral pathogens that can infect humans and multiple other species, causing severe diseases. However, knowledge of parvoviruses that infect equids is limited. In the present study, we found that three equine parvoviruses (EqPVs), namely, equine parvovirus-hepatitis (EqPV-H), equine parvovirus-cerebrospinal fluid (EqPV-CSF) and equine copivirus (EqCoPV) cocirculated among horses in China. We examined the prevalence of these three EqPVs in 225 horse serum samples in China and found EqPV-H, EqPV-CSF and EqCoPV viremia in 7.6% (17/225), 2.7% (6/225) and 2.2% of samp...
Patroca da Silva S, Barbosa de Almeida Medeiros D, Ribeiro Cruz AC, Marques França AF, Diniz Nunes BT, Guerreiro Rodrigues DS, Pinto da Silva EV....In 2018, during the surveillance for West Nile virus (WNV) in horses with neurological clinical signs in the state of Espírito Santo (Brazil), 19 animals were investigated, and 52 biological samples were collected for WNV diagnostic. One brain sample was positive for WNV by RT-qPCR and the virus was isolated in C6/36 cell culture and sequenced. We obtained a nearly complete genome of WNV co-infected with Peruvian horse sickness virus (PHSV) in the cell culture. After confirmation of PHSV by next-generation sequencing, a new PHSV RT-qPCR protocol was developed, which was used to detect another...
Taesuji M, Rattanamas K, Kulthonggate U, Mamom T, Ruenphet S.The immune responses of animals infected with African horse sickness (AHS) virus are determined by enzyme-linked immunosorbent assay (ELISA), complement fixation, and virus neutralization test. During the outbreaks of AHS in Thailand, the immune response after vaccination has been monitored using commercial test kits such as blocking ELISA, which are expensive imported products unavailable commercially in Thailand. This study aimed to assess the sensitivity and specificity of anti-AHS virus antibodies using dot blotting based on monovalent and polyvalent strains of live attenuated AHS vaccine....
Dürrwald R, Kolodziejek J, Oh DY, Herzog S, Liebermann H, Osterrieder N, Nowotny N.(1) Background: Vaccination of horses and sheep against Borna disease (BD) was common in endemic areas of Germany in the 20th century but was abandoned in the early 1990s. The recent occurrence of fatal cases of human encephalitis due to Borna disease virus 1 (BoDV-1) has rekindled the interest in vaccination. (2) Methods: The full genomes of the BD live vaccine viruses "Dessau" and "Giessen" were sequenced and analyzed for the first time. All vaccination experiments followed a proof-of-concept approach. Dose-titration infection experiments were performed in rabbits, based on both cell culture...
Li J, Zhang X, Bai B, Zhang M, Ma W, Lin Y, Wang X, Wang XF.All lentiviruses encode a post-transcriptional transactivator, Rev, which mediates the export of viral mRNA from the nucleus to the cytoplasm and which is required for viral gene expression and viral replication. In the current study, we demonstrate that equine infectious anemia virus (EIAV), an equine lentivirus, encodes a second post-transcriptional transactivator that we designate Grev. Grev is encoded by a novel transcript with a single splicing event that was identified using reverse transcription-PCR (RT-PCR) and RNA-seq in EIAV-infected horse tissues and cells. Grev is about 18 kDa in...
Pusterla N.Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In equids, equine coronavirus has been associated with diarrhea in foals and lethargy, fever, anorexia, and occasional gastrointestinal signs in adult horses. Although horses seem to be susceptible to the human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) based on the high homology to the ACE-2 receptor, they seem to be incidental hosts because of occasional SARS-CoV-2 spillover from humans. However, until more clinical and seroepidemiological data are available, it remains important to m...
Rotavirus species A (RVA) is a pathogen mainly affecting children under five years old and young animals. The infection produces acute diarrhea in its hosts and, in intensively reared livestock animals, can cause severe economic losses. In this study, we analyzed all RVA genomic constellations described in animal hosts. This review included animal RVA strains in humans. We compiled detection methods, hosts, genotypes and complete genomes. RVA was described in 86 animal species, with 52% (45/86) described by serology, microscopy or the hybridization method; however, strain sequences were not de...
Finger MA, Biava JS, Dornbusch PT, Perotta JH, Ullmann LS, Serpa PBDS, Kmetiuk LB, Dos Santos AP, Biondo AW, Leutenegger C, Filho IRB.Molecular approaches to diagnose respiratory viruses have provided an opportunity for early and subclinical pathogen detection, particularly in samples from the upper respiratory tract. This study aimed to investigate the presence of herpesviruses, particularly equid herpesvirus (EHV)-2 and EHV-5, in samples from the lower respiratory tract of healthy racehorses from Southern Brazil. Unassigned: Samples from the lower respiratory tract (i.e., bronchoalveolar lavage fluid [BALF]) were assessed by video endoscopy, cytological evaluation of BALF, and tracheal aspirates (TA), along with quantitati...
Olufemi OT, Edeh ER, Isyaku MS, Haliru M, Samaila S, Mshelia PW, Owolodun OA, Newton JR, Daly JM.Equine influenza (EI) is a fast-spreading respiratory disease of equids caused by equine influenza A virus (EIV), often resulting in high morbidity and a huge economic impact on the equine industry globally. In this cross-sectional study to determine the seroprevalence of EI and its associated risk factors, sera from 830 horses bled on a single occasion in Northwest Nigeria between October 2019 and January 2020 were screened for antibodies to A/equine/Richmond/1/2007 (H3N8) using the single radial haemolysis (SRH) assay. Antibodies were detected in 71.3% (592/830, 95% CI: 68−74%) of horses (...
Ahmed BM, Bayoumi MM, Farrag MA, Elgamal MA, Daly JM, Amer HM.Equine influenza is an important cause of respiratory disease in equids. The causative virus; EIV, is highly variable and can evolve by accumulation of mutations, particularly in the haemagglutinin (HA) gene. Currently, H3N8 is the sole subtype circulating worldwide with Florida clade 1 (FC1) is most prevalent in the Americas and FC2 in Asia and Europe. In Egypt, EIV was detected in two occasions: subtype H7N7 in 1989 and subtype H3N8 (FC1) in 2008. No data is available on the circulation pattern of EIV during the last decade despite frequent observation of suspected cases. Twenty-two nasal sw...
Powers AM, Oberste MS, Brault AC, Rico-Hesse R, Schmura SM, Smith JF, Kang W, Sweeney WP, Weaver SC.Venezuelan equine encephalitis (VEE) epidemics and equine epizootics occurred periodically in the Americas from the 1920s until the early 1970s, when the causative viruses, subtypes IAB and IC, were postulated to have become extinct. Recent outbreaks in Columbia and Venezuela have renewed interest in the source of epidemic/epizootic viruses and their mechanism of interepizootic maintenance. We performed phylogenetic analyses of VEE virus isolates spanning the entire temporal and geographic range of strains available, using 857-nucleotide reverse transcription-PCR products including the E3 and ...
Leroux C, Issel CJ, Montelaro RC.We have investigated the genetic evolution of three functionally distinct regions of the equine infectious anemia virus (EIAV) genome (env, rev, and long terminal repeat) during recurring febrile episodes in a pony experimentally infected with a well-characterized reference biological clone designated EIAV(PV). Viral populations present in the plasma of an EIAV(PV)-infected pony during sequential febrile episodes (18, 34, 80, 106, and 337 days postinfection) were amplified from viral RNA, analyzed, and compared to the inoculated strain. The comparison of the viral quasispecies showed that the ...
Lyons S, Kapoor A, Sharp C, Schneider BS, Wolfe ND, Culshaw G, Corcoran B, McGorum BC, Simmonds P.Although the origin of hepatitis C virus infections in humans remains undetermined, a close homolog of this virus, termed canine hepacivirus (CHV) and found in respiratory secretions of dogs, provides evidence for a wider distribution of hepaciviruses in mammals. We determined frequencies of active infection among dogs and other mammals in the United Kingdom. Samples from dogs (46 respiratory, 99 plasma, 45 autopsy samples) were CHV negative by PCR. Screening of 362 samples from cats, horses, donkeys, rodents, and pigs identified 3 (2%) positive samples from 142 horses. These samples were gene...
Marsh GA, Wang LF.Henipavirus, including Hendra and Nipah viruses, is a group of emerging bat-borne paramyxoviruses which were responsible for severe disease outbreaks in humans, horses and pigs. The mortality rate of human infection varies between 50 and 100%, making them one of the most deadly viruses known to infect humans. Its use of highly conserved cell surface molecules (ephrin) as entry receptors and its highly effective replication and fusion strategies are believed to be important characteristics responsible for its high pathogenicity. Henipavirus also encodes multiple accessory proteins which play a ...
Shehu-Xhilaga M, Ablan S, Demirov DG, Chen C, Montelaro RC, Freed EO.The Gag proteins of a number of different retroviruses contain late or L domains that promote the release of virions from the plasma membrane. Three types of L domains have been identified to date: Pro-Thr-Ala-Pro (PTAP), Pro-Pro-X-Tyr, and Tyr-Pro-Asp-Leu. It has previously been demonstrated that overexpression of the N-terminal, E2-like domain of the endosomal sorting factor TSG101 (TSG-5') inhibits human immunodeficiency virus type 1 (HIV-1) release but does not affect the release of the PPPY-containing retrovirus murine leukemia virus (MLV), whereas overexpression of the C-terminal portion...
Grieder FB, Vogel SN.To investigate the role of type I interferon (IFN) and its regulatory transacting proteins, interferon regulatory factors (IRF-1 and IRF-2), in early protection against infection with virulent Venezuelan equine encephalitis virus (VEE), we utilized mice with targeted mutations in the IFN-alpha/beta receptor, IRF-1, or IRF-2 genes. IFN-alpha/beta-receptor knockout mice are highly susceptible to peripheral infection with virulent or attenuated VEE, resulting in their death within 24 and 48 h, respectively. Treatment of normal macrophages with anti-IFN-alpha/beta antibody prior to and during infe...
Payne SL, Fang FD, Liu CP, Dhruva BR, Rwambo P, Issel CJ, Montelaro RC.The extent and nature of genomic variation among nine antigenically distinct EIAV isolates recovered during sequential clinical episodes from two experimentally infected ponies were examined by restriction fragment analysis and nucleotide sequencing. Only minor variations in restriction enzyme patterns were observed among the viral genomes. In contrast, env gene sequences of four isolates from one pony revealed numerous clustered base substitutions. Divergence in env gene nucleotide and deduced amino acid sequences between pairs of virus isolates ranged from 0.62 to 3.4% env gene mutation rate...
Kay BH, Boyd AM, Ryan PA, Hall RA.Host feeding patterns of mosquitoes were assessed through the identification of 865 blood meals collected from Brisbane during 2000-2001. Under natural conditions, mosquito feeding (including that of Culex annulirostris, Aedes vigilax, and Aedes notoscriptus) was primarily on dogs (37.4%), but also on birds (18.4%), horses (16.8%), brushtail possums (13.3%), humans (11.6%), and cats, flying foxes, and macropods, depending on site. From 1997 to 1999, sera (N=1706) were collected from dogs, cats, horses, flying foxes, and brushtail possums in the Brisbane area and were analyzed by microneutraliz...
Edington N, Bridges CG, Patel JR.Eight mares were infected with equid herpesvirus-1 subtype 1 isolated from a case of equine paresis. In two mares killed at 4 d.p.i. immunofluorescence showed endothelial cell infection together with thrombosis in the rete arteriosus of the nasal mucosa and also in the spinal cord of one of these mares. Circulating platelet counts in the other six mares fell as early as 2 d.p.i. and remained depressed for seven days. Circulating immune complexes started to appear at 2 d.p.i., reached maximum levels at 10 d.p.i., but were undetectable at 28 d.p.i. Three of the six remaining mares developed vary...
Rico-Hesse R, Weaver SC, de Siger J, Medina G, Salas RA.One of the most important questions in arbovirology concerns the origin of epidemic Venezuelan equine encephalitis (VEE) viruses; these viruses caused periodic, extensive epidemics/epizootics in the Americas from 1938-1973 (reaching the United States in 1971) but had recently been presumed extinct. We have documented the 1992 emergence of a new epidemic/epizootic VEE virus in Venezuela. Phylogenetic analysis of strains isolated during two outbreaks indicated that the new epidemic/epizootic virus(es) evolved recently from an enzootic VEE virus in northern South America. These results suggest co...
Ma G, Azab W, Osterrieder N.The equine herpesviruses type 1 (EHV-1) and 4 (EHV-4) are ubiquitous pathogens that affect horse populations on all continents. Despite widespread vaccination, EHV-1 and EHV-4 infections remain a permanent risk. While the two viruses share a high degree of genetic and antigenic similarity, they differ significantly in host range and pathogenicity. Compared to EHV-4, which mainly infects horses and causes respiratory disease, EHV-1 has a broader host range and can result in respiratory disease, abortions, neonatal death, and equine herpesvirusmyeloencephalopathy (EHM). Recent studies have eluci...
Brault AC, Powers AM, Chavez CL, Lopez RN, Cachón MF, Gutierrez LF, Kang W, Tesh RB, Shope RE, Weaver SC.Eastern equine encephalitis virus (EEEV), the sole species in the EEE antigenic complex, is divided into North and South American antigenic varieties based on hemagglutination inhibition tests. Here we describe serologic and phylogenetic analyses of representatives of these varieties, spanning the entire temporal and geographic range available. Nucleotide sequencing and phylogenetic analyses revealed additional genetic diversity within the South American variety; 3 major South/Central American lineages were identified including one represented by a single isolate from eastern Brazil, and 2 lin...
Hilbe M, Herrsche R, Kolodziejek J, Nowotny N, Zlinszky K, Ehrensperger F.Borna disease virus (BDV) is the causative agent of severe T-cell-mediated meningoencephalitis in horses, sheep, and other animal species in central Europe. Here we report the first unequivocal detection of a BDV reservoir species, the bicolored white-toothed shrew, Crocidura leucodon, in an area in Switzerland with endemic Borna disease.
Weaver SC, Hagenbaugh A, Bellew LA, Gousset L, Mallampalli V, Holland JJ, Scott TW.Evolution of viruses in the eastern equine encephalomyelitis (EEE) complex was studied by analyzing RNA sequences and oligonucleotide fingerprints from isolates representing the North and South American antigenic varieties. By using homologous sequences of Venezuelan equine encephalomyelitis virus as an outgroup, phylogenetic trees revealed three main EEE virus monophyletic groups. A North American variety group included all isolates from North America and the Caribbean. One South American variety group included isolates from the Amazon basin in Brazil and Peru, while the other included strain...
Scheel TK, Kapoor A, Nishiuchi E, Brock KV, Yu Y, Andrus L, Gu M, Renshaw RW, Dubovi EJ, McDonough SP, Van de Walle GR, Lipkin WI, Divers TJ....Nonprimate hepacivirus (NPHV) is the closest known relative of hepatitis C virus (HCV) and its study could enrich our understanding of HCV evolution, immunity, and pathogenesis. High seropositivity is found in horses worldwide with ∼ 3% viremic. NPHV natural history and molecular virology remain largely unexplored, however. Here, we show that NPHV, like HCV, can cause persistent infection for over a decade, with high titers and negative strand RNA in the liver. NPHV is a near-universal contaminant of commercial horse sera for cell culture. The complete NPHV 3'-UTR was determined and consists...
Sellon DC, Perry ST, Coggins L, Fuller FJ.In situ hybridization of tissues from two horses infected with the wild-type Wyoming strain of equine infectious anemia virus (EIAV) identified the liver, spleen, lymph nodes, kidney, lung, and adrenal gland as the primary host tissue sites for viral transcription during acute infection. Combined immunohistochemistry, with a monoclonal antibody recognizing a cytoplasmic antigen of equine mononuclear phagocytes, and in situ hybridization for viral RNA identified most infected cells as mature tissue macrophages. In contrast, in situ hybridization of adherent peripheral blood mononuclear cells co...
Morens DM, Taubenberger JK.To understand human influenza in a historical context of viral circulation in avian species, mammals, and in the environment. Methods: Historical review. Methods: Global events in a variety of circumstances over more than 3,000 years time. Methods: Comprehensive review of the historical literature including all major publications on pandemic and panzootic influenza. Methods: Influenza pandemics, panzootics, major epidemics and epizootics, and instances of interspecies transmission of influenza A. Results: Extensive documentation of human and animal influenza over many centuries suggests that i...
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.
Blitvich BJ, Bowen RA, Marlenee NL, Hall RA, Bunning ML, Beaty BJ.We evaluated the ability of epitope-blocking enzyme-linked immunosorbent assays (ELISAs) to detect West Nile virus (WNV) antibodies in domestic mammals. Sera were collected from experimentally infected horses, cats, and pigs at regular intervals and screened in ELISAs and plaque reduction neutralization tests. The diagnostic efficacies of these techniques were similar.
Perryman LE, O'Rourke KI, McGuire TC.Six normal and four immunodeficient horses were injected with a cloned variant of equine infectious anemia virus (EIAV). The six normal horses had detectable EIAV in their plasma by 7 days postinjection. During their primary viremic episode, which was accompanied by fever and anemia, maximum titers of EIAV in plasma ranged from 10(3.8) to 10(4.8) 50% tissue culture infective doses per ml. All six normal horses cleared detectable virus from their plasma by 21 to 35 days after injection. Horses with combined immunodeficiency became viremic by 9 days postinjection and also developed anemia. In co...
Seino KK, Long MT, Gibbs EP, Bowen RA, Beachboard SE, Humphrey PP, Dixon MA, Bourgeois MA.We used a severe challenge model that produces clinical West Nile virus (WNV) disease to test the efficacy of three commercially available equine WNV vaccines in horses. Twenty-four healthy, WNV-seronegative horses of varying ages and genders were placed, in random and blind manner, into three trial groups consisting of eight horses each; two horses in each group received (i) an inactivated WNV vaccine (K-WN), (ii) a modified-live vaccine (CP-WN) containing the WNV prM and E proteins expressed by a canarypox vector, (iii) a live-chimera vaccine (WN-FV) containing WNV prM and E proteins express...
Vannella KM, Moore BB.Idiopathic pulmonary fibrosis (IPF) remains exactly that. The disease originates from an unknown cause, and little is known about the mechanisms of pathogenesis. While the disease is likely multi-factorial, evidence is accumulating to implicate viruses as co-factors (either as initiating or exacerbating agents) of fibrotic lung disease. This review summarizes the available clinical and experimental observations that form the basis for the hypothesis that viral infections may augment fibrotic responses. We review the data suggesting a link between hepatitis C virus, adenovirus, human cytomegalo...
Lichtenstein DL, Rushlow KE, Cook RF, Raabe ML, Swardson CJ, Kociba GJ, Issel CJ, Montelaro RC.As an important enzyme in DNA synthesis, dUTPase is present in a wide variety of organisms and viruses and has been identified as a component of the equine infectious anemia virus (EIAV) pol gene. The role of EIAV dUTPase, designated DU, in virus replication in vitro and in vivo was investigated with a recently described infectious molecular clone of EIAV. A deletion mutant that was deficient in dUTPase activity was constructed, and its replication kinetics was examined in fetal equine kidney (FEK) cells and primary equine bone marrow macrophage (EBMM) cells. In FEK cells, which are permissive...
Gray WL, Baumann RP, Robertson AT, Caughman GB, O'Callaghan DJ, Staczek J.The regulation of equine herpesvirus type 1 (EHV-1) transcription was examined in infected rabbit kidney cells using metabolic inhibitors. In order to map EHV-1 immediate early, early, and late transcripts, viral RNA was 32P-labeled in vivo and hybridized to EHV-1 DNA restriction fragments immobilized on nitrocellulose filters. Immediate early viral RNA was mapped to one region of the viral genome within the inverted repeat DNA sequences (map units 0.78-0.83 and 0.95-1.0). Northern blot hybridization analysis using a 32P-labeled cloned DNA probe from this region identified a single immediate e...
Whalley JM, Robertson GR, Davison AJ.The genome of an Australian isolate of equine herpesvirus type 1 (equine abortion virus) has been analysed using the restriction endonucleases EcoRI, BglII and BamHI, and a physical map constructed. Terminal fragments were identified by exonuclease treatments, and linkage of fragments was deduced by a combination of single- and double-digest experiments and cross-blot hybridizations. The genome has a mol. wt. of 100 x 10(6) and is comprised of a short unique region bounded by repetitive sequences, which is present in both orientations in approximately equal amounts in the DNA population, and a...
Ott DE, Coren LV, Sowder RC, Adams J, Nagashima K, Schubert U.Some retroviruses contain monoubiquitinated Gag and do not bud efficiently from cells treated with proteasome inhibitors, suggesting an interaction between the ubiquitin-proteasome system and retrovirus assembly. We examined equine infectious anemia virus (EIAV) particles and found that approximately 2% of the p9(Gag) proteins are monoubiquitinated, demonstrating that this Gag protein interacts with an ubiquitinating activity. Different types of proteasome inhibitors were used to determine if proteasome inactivation affects EIAV release from chronically infected cells. Pulse-chase immunoprecip...
