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.
Gräf T, Rodriguez MC, de Oliveira Brandão Y, Royer CA, do Nascimento Ferreira C, Confortin C, Zanluca C, Strottmann DM, Duarte Dos Santos CN....Rocio virus (ROCV), a neurotropic arbovirus of the genus, caused Brazil’s largest encephalitis outbreak in the 1970s but has since been rarely detected. We report the first ROCV encephalitis clinical case after nearly 40 years and isolated and sequenced the virus from CNS tissue of a horse. Metatranscriptomics enabled full-genome sequencing, revealing divergence from the reference sequence at an evolutionary rate of 5.8–7.0 × 10⁻⁴, consistent with . Thirty-one non-synonymous substitutions were identified, with the envelope protein most affected. Findings indicate ROCV cryptic circula...
Ehizibolo DO, Oyekan O, Mkpuma N, Haliru H, Garba I, Turaki IZ, Williams EE, Danmarwa A, Mohammed A, Muhammad MA, Abubakar M, Brown C, Faburay B.Rift Valley Fever (RVF) is a neglected vector-borne zoonotic disease of significant veterinary and public health concern in Sub-Saharan Africa. This study investigated the seroprevalence of Rift Valley Fever Virus (RVFV) exposure and associated risk factors among camels and horses marketed in northern Nigeria. A total of 1117 animals were sampled, comprising camels (812) and horses (305), across three major livestock markets (Maigatari, Maiduguri, and Illela). The overall seroprevalence was 18.8% (95% CI: 16.6-21.2%), with a striking six-fold disparity: camels showed a prevalence of 24.4% (95%...
Acevedo-Jiménez GE, Morales-González C, Akbarin MM, Rodríguez-Murillo C, González-Fernández VD, Avila-De la Vega LM, García-Flores MM....Equine infectious anemia virus (EIAV) is a globally significant equine pathogen, and its control relies on effective serological surveillance. The agar gel immunodiffusion (AGID) test, the WOAH-prescribed method, has limitations in sensitivity. This study developed and validated an indirect ELISA using a synthetic peptide derived from a conserved region of the EIAV gp90 surface glycoprotein. The assay was evaluated using 773 horse sera from the Metropolitan Zone of the Valley of Mexico and compared to the AGID test. The gp90-EIAV ELISA demonstrated a sensitivity of 85.3 % and a specificity o...
Zanacchi A, Fruscione F, Grasselli S, Razzuoli E, Pastorino L, Di Lisa D.Developing advanced preclinical in vitro cancer models is essential for understanding tumor biology, improving drug discovery, and enhancing the clinical translation of new therapies. Papillomaviruses (PVs) cause diverse lesions in humans and animals; notably, bovine papillomavirus (BPV) is the main cause of equine sarcoid, the most common skin tumor in horses. Its pathogenesis involves viral infection, fibroblast transformation, and extracellular matrix (ECM) remodeling. These processes highlight the limitations of conventional two-dimensional (2D) culture systems, which fail to replicate the...
Penzhorn L, Crafford JE, Guthrie AJ.African horse sickness (AHS) is the only equine disease for which the World Organisation for Animal Health (WOAH) gives official disease-free status, given that it poses a major threat to the equine industry. The disease is caused by AHS virus (AHSV; family , taxon species ), which is endemic in sub-Saharan Africa. Reverse-transcription quantitative real-time PCR (RT-qPCR) is a rapid, sensitive detection method used in the diagnosis of AHS and the certification of animals as negative for AHSV for the purpose of movement. Genetic variability of AHSV may influence the accuracy of RT-qPCR detecti...
Mkpuma N, Meseko C, Shittu I, Chukwu C, Afiukwa FN, Iroha IR, Muhammad M, Ogbu O.Equine influenza virus (EIV) H3N8 is a highly contagious respiratory pathogen that poses significant health and economic risks to equids globally. In southeastern Nigeria where equids are sold and slaughtered, limited data exist on EIV epidemiology and circulating lineages. Methods: To address this gap, an active surveillance was conducted between January 2022 and October 2023. A total of 400 nasal swabs were collected from horses and donkeys at slaughterhouses and animal markets. The swabs were screened for equine influenza virus (EIV) using quantitative Reverse-Transcription Polymerase Chain...
Li Z, Yu T, Ge L, Lv S, Fu Q, Shi H.Equine herpesvirus type 1 (EHV-1) is a major veterinary pathogen causing significant economic losses in the livestock industry. Despite its impact, effective vaccines and targeted antiviral strategies remain limited, largely due to an incomplete understanding of host factors regulating viral replication and pathogenesis. Unassigned: To systematically identify host genes essential for EHV-1 infection, we established a BHK-21 cell line stably expressing Cas9 and performed a genome-wide CRISPR/Cas9 knockout screen using a pooled lentiviral single-guide RNA library. Significantly enriched candidat...
Schmitz M, Neugebauer E, Full F, Conn KL.Comparative transcriptomics offers a powerful approach to elucidate host-virus interactions across related pathogens, yet systematic evaluations across species-matched cellular systems remain limited. We performed a cross-species RNA sequencing analysis of respective species' cells infected with three alphaherpesviruses-herpes simplex virus 1 (HSV-1), bovine alphaherpesvirus 1 (BHV-1), and equid alphaherpesvirus 1 (EHV-1)-to dissect conserved and virus-specific transcriptional responses. We show that certain orthologous genes and orthologous pathways are differentially regulated upon infection...
Schliewert EC, Hooijberg EH, Goddard A.African horse sickness (AHS), caused by the vector-borne African horse sickness virus (AHSV), is endemic to sub-Saharan Africa and infection results in high mortality in naïve equine populations. Clinical signs include submucosal petechiae and prolonged bleeding post venepuncture indicative of hypocoagulation. Pathological activation of haemostasis may result from tissue factor expression as a result of vascular endothelial damage or dysfunction, the proposed pathologic mechanism in AHS, potentially resulting in disseminated intravascular coagulation (DIC). Objective: To describe haemostatic ...
Thieulent CJ, Sarkar S, Carossino M, Bhowmik M, Zhu H, Balasuriya UBR.Our laboratory identified the susceptible allelic variant of equine CXCL16 protein (EqCXCL16S) as an entry receptor for equine arteritis virus (EAV). However, EAV has a broad host cell tropism and infects cells that lack EqCXCL16S. Thus, we hypothesized that EAV interacts with other host cell protein(s) that facilitate EAV infection. A virus overlay protein-binding assay in combination with a Far-Western blot from EAV-susceptible equine pulmonary artery endothelial cells (EECs) and equine dermal fibroblasts (E. Derm) identified a 57 kDa protein, present in the membrane fraction of the protein ...
Beniwal N, Lal B, Mithina S, Verma CK, Kumar S, Phagna V, Jakhar K, Sonar S, Gupta V, Singh R, Kumar N, Tan CW, Thachamvally R, Singha H, Murzello K....Rabies is a neglected tropical zoonotic disease caused by rabies-virus (RV) infection and is responsible for almost 60,000 annual deaths globally, largely affecting the socio-economically disadvantaged population. Although fatality is preventable by immunization either before or after exposure with therapeutic antibodies, the high cost of prophylaxis or treatment limits their accessibility for the affected population. However, due to the almost 100% fatality rate in symptomatic individuals, almost 29 million annual vaccinations are performed, imposing high financial burden. Human transmission ...
Garzaro D, Rodríguez N, Medina G, Alcazar W, Gualdron M, Siem JA, Sulbaran Y, Barrios M, Liprandi F, Jaspe RC, Pujol FH.Madariaga virus (MADV), formerly known as the South American variant of Eastern Equine Encephalitis virus (EEEV), is an alphavirus that belongs to the family and has been periodically infecting equids in Venezuela since its first identification in 1975. This study reports the isolation and molecular characterization of MADV isolated from a horse in December 2024 in the context of MADV cases reported in Venezuela. Methods: Antibodies to the rabies virus were detected by indirect immunofluorescence, and to the Equine Infectious Anemia virus (EIAV) by passive immunodiffusion. MADV RNA was detect...
Cooper CJ, Arroyo LG, Hammermueller JD, Botts MM, Pearl DL, Wootton SK, Lillie BN.Equine herpesvirus-1 (EHV-1) is ubiquitous in the horse population, but prevalence estimates have ranged from 3 to 88% depending on the population and method of sampling. No prevalence studies have been carried out in Ontario, Canada. The objective of this study was to measure the prevalence of EHV-1 shedding in healthy broodmares in Ontario. A total of 381 mares from 42 farms in Ontario were sampled, including pregnant and barren broodmares. Samples were collected from the nose, vagina, and blood of each mare up to 6 times from December 2016 through October 2017 using a cross-sectional study ...
Jager MC, Luethy D, Shallop S, Cathcart J, Divers TJ, Tan JY, Beasley EM, Johnson P, Leduc L, Smith C, Jamieson CA, Magdesian KG, Van de Walle GR....Equine hepacivirus (EqHV) is closely related to hepatitis C virus (HCV), which causes persistent infection and chronic hepatitis in people. Information on persistent EqHV infection and hepatitis is limited. Objective: To report 19 cases of chronic hepatitis and persistent EqHV infection. Methods: Mixed retrospective and prospective case series. Methods: Inclusion criteria were: (1) chronic hepatitis, defined as persistently increased serum liver biomarkers, increased serum liver biomarkers accompanied by histopathological evidence of chronicity, for example, fibrosis, or both; (2) positive ser...
Ketphan W, Sato M, Tsujimura K, Mizutani T, Takemae H.Equine rhinitis B virus (ERBV), a member of the Picornaviridae family, is associated with mild to moderate respiratory illness in horses, yet its genomic diversity remains incompletely characterized. In this study, we performed metagenomic analysis on a rectal swab sample from a diarrheic foal confirmed to be positive for rotavirus A. Unexpectedly, we identified a highly divergent ERBV strain with a 9,448-nucleotide genome encoding a 2,721-amino-acid polyprotein. Sequence analysis revealed only 62.5-63.1% identity in the polyprotein and 47.1-49.8% in the VP1 region compared to known ERBV serot...
Pourmahdi Borujeni M, Ghobadian Diali H, Mashhadi AG, Aliabad MJ.The recent identification of novel viruses associated with hepatitis in horses has prompted equine veterinarians to investigate the viral factors contributing to equine hepatitis. Hepacivirus equi (EqHV), a member of the Flaviviridae family within the Hepacivirus genus, has been detected in horses affected by hepatitis. Globally, EqHV is highly conserved, existing as a single genotype with three distinct subtypes (Subtypes 1-3). Numerous studies have detected the virus by PCR and identified EqHV-specific antibodies through serological tests in different regions worldwide. However, to the best ...
Barua S, Tarannum A, Huber L, Easterwood LA, Velayudhan B, Da Silveira BP, Enyetornye B, Cohen ND, Dimitrov KM, Schwarz ER, Awtrey A, Groover E....Over the past decade, newly identified equine hepatotropic flavi- and parvoviruses, such as equine parvovirus-hepatitis (EqPV-H) and equine hepacivirus (EqHV), have generated considerable scientific and clinical interest. Pegiviruses, including Pegivirus (P.) caballi and P. equi, are also recognized and known to frequently cause persistent infections. However, comprehensive epidemiological data in the United States remain limited. This study analyzed 1195 equine serum samples collected from university-owned horses and diagnostic submissions across Alabama, Georgia, and Texas. Quantitative PCR ...
Liang S, Xu Z, Liu X, Yang Y, Zhao L, Hu C, Hou J, Wei Z, Zhang Y, Li D, Yang J, Zhang J, Bi J, Wang Y, Lou Z.Western equine encephalitis virus (WEEV), a group of encephalitic alphaviruses that cause severe diseases in humans and equids, historically used the very-low-density lipoprotein receptor (VLDLR) as a receptor during infection. However, current epidemic strains no longer use VLDLR as a receptor. In this study, we identify that LA1, LA2, LA3, and LA5 of VLDLR can directly interact with WEEV. Using cryo-electron microscopy, we investigate the structures of complexes formed between WEEV and VLDLR-LBD or other VLDLR fragments. Our findings show that LA1 and LA2 insert into a cleft formed by two ad...
In 2017, Spain reported its first equine infectious anemia virus (EIAV) outbreak in 34 years, affecting three horses in two unrelated holdings in Candeleda (Ávila) and Serradilla (Cáceres), with no apparent epidemiological link between premises. Phylogenetic analysis of whole genome and the gene revealed that the Spanish EIAV strains form a distinct monophyletic clade, sharing more than 99% nucleotide identity, suggesting a common contamination event. Interestingly, these three viral strains seem to cluster with North American strains, sharing up to 80.12% nucleotide identity, notably with ...
Gonzálvez M, Franco JJ, Cano-Terriza D, Barbero-Moyano J, Jose-Cunilleras E, García J, Alguacil E, García-Bocanegra I.Equine Infectious Anemia (EIA) is a notifiable disease caused by Equine Infectious Anemia Virus (EIAV), with major sanitary and economic importance for equids worldwide. There is limited and outdated information on the circulation of EIAV in many European countries. In the present study, we aimed to assess virus exposure in different equid species in Western Europe. Methods: Between 2011 and 2023, a cross-sectional study was conducted to investigate the seroprevalence of EIAV in 1676 equids (1444 horses, 106 donkeys and 126 mules/hinnies) from four European regions: Andalusia (Southern Spain; ...
Bhat S, Karunakaran S, Frossard JP, Choudhury B, Steinbach F.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a notifiable respiratory and reproductive disease of equids that causes significant losses to the equine industry. This study presents a comprehensive analysis of two EAV outbreaks in the UK in 2019, combining virus isolation, sequencing and phylogenetic analysis to provide a holistic understanding of EAV dynamics in these outbreaks. Genetic characterization revealed that all outbreak strains were similar to viruses detected in the UK and Europe from 2004 to 2011, belonging to phylogroup D and clustering in two grou...
Morales J, Ruano MJ, Tena-Tomás C, van Schalkwyk A, Loundras EA, Valero-Lorenzo M, López-Herranz A, Romito M, Batten C, Villalba R, Agüero M.African horse sickness (AHS) is a disease affecting equids caused by the AHS virus (AHSV). The World Organisation for Animal Health (WOAH) includes AHS as a notifiable disease and, upon detection within the European Union, immediate control and eradication measures are mandated. Thus, validated diagnostic methods for rapid AHSV detection are essential. The Agüero 2008 and Guthrie 2013 rRT-PCR methods have been widely validated for detection of any AHSV strain and are included as reference rRT-PCRs in the WOAH manual. However, the WOAH Reference Laboratory for AHS in the Republic of South Afri...
Conn KL.Equid alphaherpesvirus 1 (EHV1) is a DNA virus that causes severe disease in equids. Some strains are neurotropic and cause disease in the central nervous system, whereas others are non-neurotropic and can cause negative reproductive outcomes. Mechanisms governing EHV1 pathotype are not understood. However, EHV1 pathotypes have different infection efficiencies and replication kinetics in various cell types. They are also differentially susceptible to epigenetic inhibitors. Aside from this observation little is known about EHV1 chromatin or how its regulation influences infection. To build know...
White J, Thompson K, van den Berg D, O'Neill G, Mendez DH, Talwar J, Degeling C, Forsythe R, Durrheim DN.With more than 60% of emerging infectious diseases being zoonotic, we apply a One Health lens that connects human, animal, and environmental dimensions of the response to a Hendra virus (HeV) event. One Health promotes collaboration among health professionals, veterinarians, environmental scientists, and policymakers to strengthen health infrastructure and improve responses to complex health threats. HeV is an uncommon high-consequence and potentially fatal zoonotic disease endemic to parts of Australia. Previous research has largely focused on the uptake of preparedness measures by veterinari...
Haywood LMB, Clark A, Hause B, Sheahan B.Many cases of equine enterocolitis are suspected to be infectious in nature, but no pathogen is identified in many cases. Objective: Perform next-generation sequencing on faeces collected from cases of equine enterocolitis for the presence of novel viruses and determine if an identified novel virus is associated with cases of equine enterocolitis. Methods: Retrospective cohort study. Methods: Next generation sequencing was performed targeting viral genomes from n = 13 pooled faecal samples (n = 5 horses/pool) with enterocolitis. Subsequent qPCR was performed targeting the highly conser...
This study presents the first investigation of West Nile virus (WNV) seroprevalence among farmed horses in Kazakhstan. In 2024, a total of 368 serum samples were collected from horses across 106 settlements in 10 regions of the Republic of Kazakhstan. Using an enzyme-linked immunosorbent assay (ELISA), antibodies to WNV were detected in 32 horses (8.7%; 95% CI: 6.2-12.0%) from six regions. Among the seropositive animals, 26 (81.25%) were females and 6 (18.75%) were males, ranging in age from 1 to 19 years. No statistically significant association between sex and the presence of antibodies to W...
Wang L, Zheng R, Li Z, Zhang L.Recent increases in cases of western equine encephalitis (WEE) in South America have raised significant concerns about the virus's potential to cause an endemic disease due to its adaptation to mosquito vectors. Currently, there are no effective vaccines or treatments for WEEV, despite ongoing research into various biochemical products in animal models. The virus presents different pathological effects depending on the host. In humans, WEEV infection leads to central nervous system damage, resulting in encephalitis and severe neurological sequelae, which underscores the need for further resear...
Tallmadge RL, Laverack M, Lejeune M, Crossley B, Diel DG.Equid herpesvirus (EHV) 1 and -4 are common viral pathogens of horses that can cause upper respiratory disease, neurological disease, abortion, and death. As characteristic alphaherpesviruses, both EHV-1 and EHV-4 can establish latency, resulting in a lifelong carrier state in infected animals. Here we describe the development and validation of a rapid and sensitive multiplex real-time PCR assay (EHV1-4MP) that simultaneously detects EHV-1 and EHV-4 and includes an endogenous internal control - melanocortin 1 receptor (MC1R) - targeting the equid genome. The EHV1-4MP assay analytical sensitiv...
Gamage C, Graves A, Li G, Thieulent CJ, Balasuriya UBR, Morrow J, Vissani A, Parreño V, Matthijnssens J, Carossino M.Equine rotavirus B (ERVB) has caused foal diarrhea in central Kentucky since 2021. Coding-complete genome sequences from 14 strains circulating in 2024 revealed >99% nucleotide identity to the 2021 prototype ERVB strain RVB/Horse-wt/USA/KY1518/2021, with a conserved genomic constellation (G3-P[3]-I3-R3-C3-M3-A4-N3-T3-E3-H3).
Bunning ML, Bowen RA, Cropp CB, Sullivan KG, Davis BS, Komar N, Godsey MS, Baker D, Hettler DL, Holmes DA, Biggerstaff BJ, Mitchell CJ.A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 isolates. Postinfection, uninfected female Ae. albopictus fed on eight of the infected horses. In the first trial, Nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 to 4, respectively. In the second trial, the seven horses with subclinical infections developed Nt a...
Komar N, Clark GG.West Nile virus (Flavivirus: Flaviviridae; WNV) has spread rapidly throughout the Caribbean Basin since its initial detection there in 2001. This report summarizes our current knowledge of WNV transmission in tropical America. Methods: We reviewed the published literature and consulted with key public health officials to obtain unpublished data. Results: West Nile virus infections first appeared in human residents of the Cayman Islands and the Florida Keys in 2001, and in apparently healthy Jamaican birds sampled early in 2002. Serologic evidence of WNV infection in 2002 was detected in horses...
Patel JR, Heldens J.This review concentrates on the epidemiology, latency and pathogenesis of, and the approaches taken to control infection of horses by equine herpesvirus types 1 (EHV-1) and 4 (EHV-4). Although both viruses may cause febrile rhinopneumonitis, EHV-1 is the main cause of abortions, paresis and neonatal foal deaths. The lesion central to these three conditions is necrotising vasculitis and thrombosis resulting from lytic infection of endothelial cells lining blood capillaries. The initiation of infection in these lesions is likely to be by reactivated EHV-1 from latently infected leukocytes. Howev...
Guy JS, Breslin JJ, Breuhaus B, Vivrette S, Smith LG.A coronavirus was isolated from feces of a diarrheic foal and serially propagated in human rectal adenocarcinoma (HRT-18) cells. Antigenic and genomic characterizations of the virus (isolate NC99) were based on serological comparison with other avian and mammalian coronaviruses and sequence analysis of the nucleocapsid (N) protein gene. Indirect fluorescent-antibody assay procedures and virus neutralization assays demonstrated a close antigenic relationship with bovine coronavirus (BCV) and porcine hemagglutinating encephalomyelitis virus (mammalian group 2 coronaviruses). Using previously des...
Snijder EJ, Wassenaar AL, Spaan WJ.To study the proteolytic processing of the equine arteritis virus (EAV) replicase open reading frame 1a (ORF1a) protein, specific antisera were raised in rabbits, with six synthetic peptides and a bacterial fusion protein as antigens. The processing of the EAV ORF1a product in infected cells was analyzed with Western blot (immunoblot) and immunoprecipitation techniques. Additional information was obtained from transient expression of ORF1a cDNA constructs. The 187-kDa ORF1a protein was found to be subject to at least five proteolytic cleavages. The processing scheme, which covers the entire OR...
Rogers GN, Pritchett TJ, Lane JL, Paulson JC.Human and animal (avian and equine) influenza A virus isolates of the H3 serotype exhibit marked differences in their ability to bind specific sialyloligosaccharide sequences that serve as cell surface receptor determinants (G. Rogers and J. Paulson, 1983, Virology 127, 361-373). Whereas human isolates of this subtype strongly agglutinate enzymatically modified human erythrocytes containing the terminal SA alpha 2,6Gal sequence, avian and equine isolates preferentially agglutinate erythrocytes bearing the SA alpha 2, 3Gal sequence. As shown in this report, a glycoprotein found in horse serum, ...
Campo MS.Tumorigenesis due to papillomavirus (PV) infection was first demonstrated in rabbits and cattle early last century. Despite the evidence obtained in animals, the role of viruses in human cancer was dismissed as irrelevant. It took a paradigm shift in the late 1970s for some viruses to be recognised as 'tumour viruses' in humans, and in 1995, more than 60 years after Rous's first demonstration of CRPV oncogenicity, WHO officially declared that 'HPV-16 and HPV-18 are carcinogenic to humans'. Experimental studies with animal PVs have been a determining factor in this decision. Animal PVs have bee...
Garmashova N, Atasheva S, Kang W, Weaver SC, Frolova E, Frolov I.The encephalitogenic New World alphaviruses, including Venezuelan (VEEV), eastern (EEEV), and western equine encephalitis viruses, constitute a continuing public health threat in the United States. They circulate in Central, South, and North America and have the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that these viruses have developed the ability to interfere with cellular transcription and use it as a means of downregulating a cellular antiviral response. The results of the present study suggest that the N-terminal, approxima...
Ewers C, Bethe A, Stamm I, Grobbel M, Kopp PA, Guerra B, Stubbe M, Doi Y, Zong Z, Kola A, Schaufler K, Semmler T, Fruth A, Wieler LH, Guenther S.To discern the relevance of ST648 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli as a putative new group of multiresistant and extraintestinal pathogenic strains in animals, its frequency, ESBL types, antimicrobial resistance patterns and virulence gene (VG) profiles should be determined and compared with ST131 strains from the same collection of strains. Methods: ESBL-producing E. coli isolates (n = 1152), consecutively sampled from predominantly dogs, cats and horses between 2008 and 2011, were assigned to a phylogenetic group by PCR. Partial multilocus sequence typing was ...
Autorino GL, Battisti A, Deubel V, Ferrari G, Forletta R, Giovannini A, Lelli R, Murri S, Scicluna MT.During the late summer of 1998, veterinary authorities in Tuscany, Italy, received reports of cases of neurologic disease among horses residing in a large wetland area located in the provinces of Florence and Pistoia. West Nile virus was isolated from two of the six horses that died or were euthanized. A retrospective epidemiologic study identified 14 clinical neurologic cases that occurred from August 20 to October 6 (attack rate of 2.8%). A serologic survey conducted over a 700-km2 area in stables with and without apparent clinical cases confirmed a wider spread of the infection, with an ove...
Hu S, Vincenz C, Buller M, Dixit VM.Molluscum contagiosum virus proteins MC159 and MC160 and the equine herpesvirus 2 protein E8 share substantial homology to the death effector domain present in the adaptor molecule Fas-associated death domain protein (FADD) and the initiating death protease FADD-like interleukin-1beta-converting enzyme (FLICE) (caspase-8). FADD and FLICE participate in generating the death signal from both tumor necrosis factor receptor-1 (TNFR-1) and the CD-95 receptor. The flow of death signals from TNFR-1 occurs through the adaptor molecule tumor necrosis factor receptor-associated death domain protein (TRA...
Savini G, Afonso A, Mellor P, Aradaib I, Yadin H, Sanaa M, Wilson W, Monaco F, Domingo M.Epizootic haemorrhagic disease (EHD) is an infectious non-contagious viral disease transmitted by insects of the genus Culicoides which affects wild and domestic ruminants. The causative agent, the epizootic haemorrhagic disease virus (EHDV), belongs to the family Reoviridae, genus Orbivirus and shares many morphological and structural characteristics with the other members of the genus such as bluetongue, African horse sickness and equine encephalosis viruses. In recent years EHD outbreaks have been reported in countries bordering the European Union. They caused disease in cattle and severe r...
Steele KE, Twenhafel NA.The encephalitides caused by Venezuelan (VEEV), eastern (EEEV), and western (WEEV) equine encephalitis viruses are important natural diseases of horses and humans and potential agents of biowarfare or bioterrorism. No licensed vaccines or specific therapies exist to prevent or treat human infections with VEEV, EEEV, or WEEV. Well-characterized animal models are needed to support the development of such medical countermeasures under the United States Food and Drug Administration's "Animal Rule." This review focuses on the pathological features and pathogenetic mechanisms of these alphaviral enc...
Criado-Fornelio A, Martinez-Marcos A, Buling-Saraña A, Barba-Carretero JC.Molecular epizootiology of piroplasmids (Babesia spp., Theileria spp.) and Hepatozoon canis was studied in mammals from southern Europe (mainly from Spain, but also from Portugal and France). Partial amplification and sequencing of the 18s rRNA gene was used for molecular diagnosis. In some particular cases (B. ovis and B. bovis) the complete 18s rRNA gene was sequenced. Blood samples were taken from domestic animals showing clinical symptoms: 10 dogs, 10 horses, 10 cows, 9 sheep and 1 goat. In addition, DNA samples were isolated from blood of 12 healthy dogs and from spleen of 10 wild red fox...
Chandriani S, Skewes-Cox P, Zhong W, Ganem DE, Divers TJ, Van Blaricum AJ, Tennant BC, Kistler AL.Theiler's disease is an acute hepatitis in horses that is associated with the administration of equine blood products; its etiologic agent has remained unknown for nearly a century. Here, we used massively parallel sequencing to explore samples from a recent Theiler's disease outbreak. Metatranscriptomic analysis of the short sequence reads identified a 10.5-kb sequence from a previously undescribed virus of the Flaviviridae family, which we designate "Theiler's disease-associated virus" (TDAV). Phylogenetic analysis clusters TDAV with GB viruses of the recently proposed Pegivirus genus, altho...
Montelaro RC, Parekh B, Orrego A, Issel CJ.The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test str...
Schneider J, Kaaden O, Copeland TD, Oroszlan S, Hunsmann G.Two glycopolypeptides with molecular weights 160,000 and 120,000 (gp120) are regularly recognized by human immunodeficiency virus (HIV)-specific antisera in lysates of cells persistently infected with HIV. In the present study, gp120 was characterized as the major envelope glycopolypeptide of HIV. Gp120 was identified as the external viral glycoprotein by radiosequencing and by its presence in purified virus. However gp120 was predominantly shed as a soluble protein into the culture fluid. Furthermore gp120 was precipitated by sera from horses infected with equine infectious anaemia virus (EIA...
Rivas F, Diaz LA, Cardenas VM, Daza E, Bruzon L, Alcala A, De la Hoz O, Caceres FM, Aristizabal G, Martinez JW, Revelo D, De la Hoz F, Boshell J....In 1995, the first Venezuelan equine encephalitis (VEE) outbreak in Colombia in 22 years caused an estimated 75,000 human cases, 3000 with neurologic complications and 300 fatal, in La Guajira State. Of the state's estimated 50,000 equines, 8% may have died. An epizootic IC virus, probably introduced from Venezuela, was rapidly amplified among unvaccinated equines. Record high rainfall, producing high densities of vector Aedes taeniorhynchus, led to extensive epidemic transmission (30% attack rate) in the four affected municipalities. Native Wayuu Indians, constituting 24% of the state's popul...
Russo AT, White MA, Watowich SJ.Alphavirus replication and propagation is dependent on the protease activity of the viral nsP2 protein, which cleaves the nsP1234 polyprotein replication complex into functional components. Thus, nsP2 is an attractive target for drug discovery efforts to combat highly pathogenic alphaviruses. Unfortunately, antiviral development has been hampered by a lack of structural information for the nsP2 protease. Here, we report the crystal structure of the nsP2 protease (nsP2pro) from Venezuelan equine encephalitis alphavirus determined at 2.45 A resolution. The protease structure consists of two dist...
Tulman ER, Delhon G, Afonso CL, Lu Z, Zsak L, Sandybaev NT, Kerembekova UZ, Zaitsev VL, Kutish GF, Rock DL.Here we present the genomic sequence of horsepox virus (HSPV) isolate MNR-76, an orthopoxvirus (OPV) isolated in 1976 from diseased Mongolian horses. The 212-kbp genome contained 7.5-kbp inverted terminal repeats and lacked extensive terminal tandem repetition. HSPV contained 236 open reading frames (ORFs) with similarity to those in other OPVs, with those in the central 100-kbp region most conserved relative to other OPVs. Phylogenetic analysis of the conserved region indicated that HSPV is closely related to sequenced isolates of vaccinia virus (VACV) and rabbitpox virus, clearly grouping to...
Field H, de Jong C, Melville D, Smith C, Smith I, Broos A, Kung YH, McLaughlin A, Zeddeman A.Hendra virus is a recently emerged zoonotic agent in Australia. Since first described in 1994, the virus has spilled from its wildlife reservoir (pteropid fruit bats, or 'flying foxes') on multiple occasions causing equine and human fatalities. We undertook a three-year longitudinal study to detect virus in the urine of free-living flying foxes (a putative route of excretion) to investigate Hendra virus infection dynamics. Pooled urine samples collected off plastic sheets placed beneath roosting flying foxes were screened for Hendra virus genome by quantitative RT-PCR, using a set of primers a...
Broder CC, Xu K, Nikolov DB, Zhu Z, Dimitrov DS, Middleton D, Pallister J, Geisbert TW, Bossart KN, Wang LF.Hendra virus and Nipah virus are bat-borne paramyxoviruses that are the prototypic members of the genus Henipavirus. The henipaviruses emerged in the 1990s, spilling over from their natural bat hosts and causing serious disease outbreaks in humans and livestock. Hendra virus emerged in Australia and since 1994 there have been 7 human infections with 4 case fatalities. Nipah virus first appeared in Malaysia and subsequent outbreaks have occurred in Bangladesh and India. In total, there have been an estimated 582 human cases of Nipah virus and of these, 54% were fatal. Their broad species tropis...
Castillo-Olivares J, Wood J.West Nile virus (WNV) is a flavivirus closely related to Japanese encephalitis and St. Louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. Occasionally, WNV infects and causes disease in other vertebrates, including humans and horses. West Nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of Europe in addition to the large epidemic that has swept across North America. This review summarises the main features of WNV infection in the horse, ...
Carrera JP, Forrester N, Wang E, Vittor AY, Haddow AD, López-Vergès S, Abadía I, Castaño E, Sosa N, Báez C, Estripeaut D, Díaz Y, Beltrán D....The eastern equine encephalitis (EEE) and Venezuelan equine encephalitis (VEE) viruses are pathogens that infect humans and horses in the Americas. Outbreaks of neurologic disease in humans and horses were reported in Panama from May through early August 2010. Methods: We performed antibody assays and tests to detect viral RNA and isolate the viruses in serum samples from hospitalized patients. Additional cases were identified with enhanced surveillance. Results: A total of 19 patients were hospitalized for encephalitis. Among them, 7 had confirmed EEE, 3 had VEE, and 1 was infected with both ...
Olson JG, Ksiazek TG, Gubler DJ, Lubis SI, Simanjuntak G, Lee VH, Nalim S, Juslis K, See R.Sera were collected from humans, cattle, horses, goats, ducks, chickens, wild birds, bats and rats in Lombok, Indonesia, and were tested by haemagglutination inhibition (HI) for antibodies to JE, ZIKA, CHIK and RR. Selected sera were tested by microneutralization tests for antibodies to the following viruses: JE, ZIKA, MVE, TMU, LGT, KUN, SEP, DEN-2, CHIK, RR, GET, SIN, BUN, BAT and BAK. Human sera had JE HI antibody in 135 (30%) of 446 tested. Neutralization tests indicated that DEN-2, ZIKA, TMU, KUN and SEP may have caused flavivirus infections. Antibodies to other arboviruses tested for wer...
