Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Giguère S, Berghaus LJ, Lee EA.Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipene...
Edson D, Field H, McMichael L, Jordan D, Kung N, Mayer D, Smith C.Bats of the genus Pteropus (flying-foxes) are the natural host of Hendra virus (HeV) which periodically causes fatal disease in horses and humans in Australia. The increased urban presence of flying-foxes often provokes negative community sentiments because of reduced social amenity and concerns of HeV exposure risk, and has resulted in calls for the dispersal of urban flying-fox roosts. However, it has been hypothesised that disturbance of urban roosts may result in a stress-mediated increase in HeV infection in flying-foxes, and an increased spillover risk. We sought to examine the impact of...
Negussie H, Gizaw D, Tessema TS, Nauwynck HJ.Although equine herpesvirus myeloencephalopathy (EHM) is a sporadic and relatively uncommon manifestation of equine herpesvirus-1 (EHV-1), it has the potential for causing devastating outbreaks in horses. Up till now, there were no reported EHM outbreaks in donkeys and mules. This study describes the isolation and molecular characterization of EHV-1 from clinically EHM-affected horses (n = 6), mules (n = 3) and donkeys (n = 82) in Ethiopia during outbreaks from May 2011 to December 2013. The incidence of EHM cases was higher from April to mid-June. EHM in donkeys was more severe and deat...
Fall M, Fall AG, Seck MT, Bouyer J, Diarra M, Balenghien T, Garros C, Bakhoum MT, Faye O, Baldet T, Gimonneau G.Culicoides biting midges (Diptera: Ceratopogonidae) are important vectors of arboviruses in Africa. Culicoides oxystoma has been recently recorded in the Niayes region of Senegal (West Africa) and its high abundance on horses suggests a potential implication in the transmission of the African horse sickness virus in this region. This species is also suspected to transmit bluetongue virus to imported breeds of sheep. Little information is available on the biology and ecology of Culicoides in Africa. Therefore, understanding the circadian host-seeking activity of this putative vector is of prima...
May CE, Guthrie AJ, Keys B, Joone C, Monyai M, Schulman ML.The response to the first outbreak of contagious equine metritis in South Africa included pioneering a web-based platform to coordinate key aspects of a national, real-time polymerase chain reaction (qPCR)-based stallion screening programme to determine the distribution and prevalence of Taylorella equigenitalis in stallions and exposed mares. Objective: To define the hypothesised pre-existing status of T. equigenitalis in the South African equine population and progression of the epidemiological investigation via the implementation of a molecular diagnostic-based surveillance programme. Metho...
López RH, Soto SU, Gallego-Gómez JC.West Nile virus (WNV) is a member of the genus Flavivirus, and it is transmitted between Culex sp. mosquitoes and avian hosts. Equids and humans are commonly infected with WNV as dead-end hosts, and the signs and symptoms of infection range from mild illness to neurologic symptoms as encephalitis, meningitis and sometimes death. Previous phylogenetic studies have classified WNV into six genetically distinct lineages and provided valuable insight on WNV dispersal patterns within the Americas and its emergence in different geographic areas. In this study, we isolated, sequenced and genetically c...
Schvartz G, Epp T, Burgess HJ, Chilton NB, Armstrong JS, Lohmann KL.Passive surveillance of ticks on horses in Saskatchewan revealed that the horses were parasitized by 3 species, Dermacentor albipictus, D. andersoni, and D. variabilis. The nymphs and adults of D. albipictus occurred on horses earlier in the year than did adults of the 2 other species. Une surveillance passive des tiques chez des chevaux de la Saskatchewan a révélé que les chevaux étaient affectés par des parasites de trois espèces: et Les nymphes et les adultes de se présentaient chez les chevaux plus tôt dans l’année que les adultes des deux autres espèces.(Traduit par Isabel...
Miño S, Kern A, Barrandeguy M, Parreño V.Group A rotaviruses (RVA) are important infectious agents associated with diarrhea in the young of several animal species including foals. Currently, a variety of diagnosis methods are commercially available, like ELISA, latex agglutination and immunochromatographic assays. These commercial tests are mainly designed for the detection of human RVA; its applicability in veterinary diagnosis has been poorly studied. The aim of this study was to compare the sensitivity and specificity of two commercial diagnostic kits, Pathfinder™ Rotavirus and FASTest Rota® strip, with an in-house KERI ELISA, ...
Bannai H, Nemoto M, Ochi A, Kikuchi T, Kobayashi M, Tsujimura K, Yamanaka T, Kondo T.To clarify the factors causing an outbreak in 2014 of Getah virus infection among racehorses at the Miho training center, Japan, we isolated virus strains and performed an epizootiological investigation of affected horses and related horse populations. Three Getah virus isolates were recovered from clinical samples, and one of them (14-I-605) was used in a virus-neutralizing test. Of the affected horses (n = 33), 20 (60.6%) were 2-year-olds. We investigated the histories of Getah virus vaccination of the affected horses and the whole population at the Miho training center. Among the 2-year-old...
Herd HR, Sula MM, Starkey LA, Panciera RJ, Johnson EM, Snider TA, Holbrook TC.This report describes 2 genetically related paint mares, case Nos. 1 and 2, presented to the Oklahoma State University Boren Veterinary Medical Teaching Hospital for chronic weight loss and abnormal gait, respectively. Notable findings in both cases included marked persistent eosinophilia and multiple intramuscular lateral thoracic masses. Histologic examination of masses revealed eosinophilic, centrally necrotic granulomas and marked eosinophilic myositis. Granulomas in case No. 1 also contained intralesional Sarcocystis sp material, and adjacent muscle fibers contained intact protozoal cysts...
Hale D.West Nile Virus is the most frequent cause of arboviral disease in the United States. It was first identified in the United States in 1999. Since that time, each of the 48 contiguous states in the United States has seen the disease, and it has been found in 96% of the U.S. counties in infected humans, mosquitoes, birds, horses, or other mammals. Although most often the disease resolves on its own, patients can develop serious and life-threatening complications, and may need further monitoring and treatment. This article reviews the prevalence, transmission, signs and symptoms, complications, t...
Yeargan M, de Assis Rocha I, Morrow J, Graves A, Reed SM, Howe DK.Enzyme-linked immunosorbent assays (ELISAs) based on the SnSAG surface antigens of Sarcocystis neurona provide reliable detection of infection by the parasite. Moreover, accurate serodiagnosis of equine protozoal myeloencephalitis (EPM) is achieved with the SnSAG ELISAs by measuring antibodies in serum and cerebrospinal fluid (CSF) to reveal active infection in the central nervous system. Two independent ELISAs based on recombinant (r)SnSAG2 or a chimeric fusion of SnSAG3 and SnSAG4 (rSnSAG4/3) are currently used together for EPM serodiagnosis to overcome varied antibody responses in different...
Drebert Z, Golke A, Cymerys J, Słońska A, Chmielewska A, Tucholska A, Bańbura MW.Equid herpesvirus type 1 (EHV-1) is a prevalent causative agent of equine diseases worldwide. After primary replication in the respiratory epithelium the virus disseminates systemically through a peripheral blood mononuclear cell (PBMC)-associated viraemia. EHV-1 is the only alphaherpes- virus known so far which is capable of establishing latent infection not only in neurons but also in immune system cells (mainly in lymphocytes and macrophages). Since leukocytes are not the target cells for viral replication but are used to transport EHV-1 to the internal organs, the questionremains how the v...
Hara Y, Nakajima T, Akamatsu M, Yahiro M, Kagawa S, Petry S, Matsuda M, Moore JE.Contagious equine metritis is a bacterial infectious disease of horses caused by Taylorella equigenitalis, a Gram-negative eubacterium. The disease has been described in several continents, including Europe, North America and Asia. A novel molecular method was developed to detect clustered regularly interspaced short palindromic repeats (CRISPRs), which were separated by non-repetitive unique spacer regions (NRUSRs) of similar length, in the Taylorella equigenitalis EQ59 strain using a primer pair, f-/r-TeCRISPR-ladder, by PCR amplification. In total, 31 Taylorella isolates (17 T. equigenitali...
Perumal AN, Gunawardene YI, Dassanayake RS.Setaria digitata is a filarial parasite that causes fatal cerebrospinal nematodiasis in goats, sheep and horses, resulting in substantial economic losses in animal husbandry in the tropics. Due to its close resemblance to Wuchereria bancrofti, this nematode is also frequently used as a model organism to study human lymphatic filariasis. This review highlights numerous insights into the morphological, histological, biochemical, immunological and genetic aspects of S. digitata that have broadened our understanding towards the control and eradication of filarial diseases.
van Kasteren PB, Knaap RC, van den Elzen P, Snijder EJ, Balasuriya UB, van den Born E, Kikkert M.Arteriviruses are a family of positive-stranded RNA viruses that includes the prototypic equine arteritis virus (EAV) and porcine reproductive and respiratory syndrome virus (PRRSV). Although several vaccines against these viruses are commercially available there is room for improvement, especially in the case of PRRSV. The ability of arteriviruses to counteract the immune response is thought to decrease the efficacy of the current modified live virus vaccines. We have recently shown that the deubiquitinase (DUB) activity of EAV papain-like protease 2 (PLP2) is important for the inhibition of ...
Amaya M, Keck F, Lindquist M, Voss K, Scavone L, Kehn-Hall K, Roberts B, Bailey C, Schmaljohn C, Narayanan A.Many viruses have been implicated in utilizing or modulating the Ubiquitin Proteasome System (UPS) to enhance viral multiplication and/or to sustain a persistent infection. The mosquito-borne Venezuelan equine encephalitis virus (VEEV) belongs to the Togaviridae family and is an important biodefense pathogen and select agent. There are currently no approved vaccines or therapies for VEEV infections; therefore, it is imperative to identify novel targets for therapeutic development. We hypothesized that a functional UPS is required for efficient VEEV multiplication. We have shown that at non-tox...
Laus F, Spaterna A, Faillace V, Veronesi F, Ravagnan S, Beribé F, Cerquetella M, Meligrana M, Tesei B.Interest in the welfare and diseases of donkeys is constantly increasing in several countries. Despite this, clinical research into donkeys needs to be in continual development since they show different reactions compared to horses in many conditions, including infectious diseases, and need specific clinical and therapeutic approaches. No reports are currently available on clinical and clinical pathology data regarding donkeys with natural piroplasms infection. Results: Venous blood samples were taken from one hundred and thirty eight donkeys and underwent indirect fluorescent antibody test (I...
Zwart L, Potgieter CA, Clift SJ, van Staden V.African horse sickness is a serious equid disease caused by the orbivirus African horse sickness virus (AHSV). The virus has ten double-stranded RNA genome segments encoding seven structural and three non-structural proteins. Recently, an additional protein was predicted to be encoded by genome segment 9 (Seg-9), which also encodes VP6, of most orbiviruses. This has since been confirmed in bluetongue virus and Great Island virus, and the non-structural protein was named NS4. In this study, in silico analysis of AHSV Seg-9 sequences revealed the existence of two main types of AHSV NS4, designat...
Rizk MA, El-Sayed SA, Terkawi MA, Youssef MA, El Said el Sel S, Elsayed G, El-Khodery S, El-Ashker M, Elsify A, Omar M, Salama A, Yokoyama N....A rapid and accurate assay for evaluating antibabesial drugs on a large scale is required for the discovery of novel chemotherapeutic agents against Babesia parasites. In the current study, we evaluated the usefulness of a fluorescence-based assay for determining the efficacies of antibabesial compounds against bovine and equine hemoparasites in in vitro cultures. Three different hematocrits (HCTs; 2.5%, 5%, and 10%) were used without daily replacement of the medium. The results of a high-throughput screening assay revealed that the best HCT was 2.5% for bovine Babesia parasites and 5% for equ...
Vilibić-Čavlek T, Barbić Ljubo , Stevanović V, Mlinarić-Galinović G.Usutu virus (USUV) belongs to the family Flaviviridae, genus Flavivirus, Japanese encephalitis serocomplex. The virus was discovered in 1959 in South Africa and has emerged since 1996 causing epizootics with high avian mortality in Europe. The importance of USUV in humans is not fully understood. However, several human clinical cases of USUV infection described so far indicate the role of this virus as an antropozoonotic agent. In Croatia, serologic evidence of USUV was first documented in 2011 in two horses from Zagreb and Sisak-Moslavina County. In 2012, USUV neutralizing antibodies were fou...
Kudirkiene E, Welker M, Knudsen NR, Bojesen AM.Streptococcus equi includes very important animal and human pathogens. S. equi subsp. equi (SEE) is a highly pathogenic equine specific subspecies, while S. equi subsp. zooepidemicus (SEZ) and S. equi subsp. ruminatorum are opportunistic pathogens of various animal species and humans. Due to great phenotypic and sequence similarity between three subspecies their discrimination remains difficult. In this study, we aimed to design and validate a novel, Superspectra based, MALDI-TOF MS approach for reliable, rapid and cost-effective identification of SEE and SEZ, the most frequent S. equi subspec...
Nemoto M, Bannai H, Tsujimura K, Kobayashi M, Kikuchi T, Yamanaka T, Kondo T.An outbreak of Getah virus infection occurred among racehorses in Japan during September and October 2014. Of 49 febrile horses tested by reverse transcription PCR, 25 were positive for Getah virus. Viruses detected in 2014 were phylogenetically different from the virus isolated in Japan in 1978.
Feng KH, Gonzalez G, Deng L, Yu H, Tse VL, Huang L, Huang K, Wasik BR, Zhou B, Wentworth DE, Holmes EC, Chen X, Varki A, Murcia PR, Parrish CR.The A/H3N8 canine influenza virus (CIV) emerged from A/H3N8 equine influenza virus (EIV) around the year 2000 through the transfer of a single virus from horses to dogs. We defined and compared the biological properties of EIV and CIV by examining their genetic variation, infection, and growth in different cell cultures, receptor specificity, hemagglutinin (HA) cleavage, and infection and growth in horse and dog tracheal explant cultures. Comparison of sequences of viruses from horses and dogs revealed mutations that may be linked to host adaptation and tropism. We prepared infectious clones o...
Talafha AQ, Abutarbush SM, Rutley DL.This study aimed to determine the seroprevalence and to identify risk factors associated with Neospora spp. infection in horses in Jordan. Management related data were collected from each farm and individual horses. Sera from 227 horses from 5 of 6 climatic regions in Jordan were analyzed for the presence of antibodies to Neospora spp. by ELISA kit. The study was performed during spring of 2010. The association between seropositivity and risk factors was analyzed. A total of 7 (3%) of 227 sera had antibodies for Neospora spp. There was a significant regional difference (P=0.018) between the 5 ...
Jongejan F, Ringenier M, Putting M, Berger L, Burgers S, Kortekaas R, Lenssen J, van Roessel M, Wijnveld M, Madder M.Autochthonous populations of Dermacentor reticulatus ticks in the Netherlands were discovered after fatal cases of babesiosis occurred in resident dogs in 2004. The presence of D. reticulatus in the Netherlands has also linked with the emergence of piroplasmosis in the resident horse population. The aim of this study was to put together results of continued surveillance of field sites and hosts for this tick in the Netherlands and also in Belgium and determine their infection status for Babesia and Theileria species. Methods: Ticks were collected from the vegetation at 11 locations between 201...
Bourret V, Croville G, Mansuy JM, Mengelle C, Mariette J, Klopp C, Genthon C, Izopet J, Guérin JL.Recent in-depth genetic analyses of influenza A virus samples have revealed patterns of intra-host viral genetic variability in a variety of relevant systems. These have included laboratory infected poultry, horses, pigs, chicken eggs and swine respiratory cells, as well as naturally infected poultry and horses. In humans, next generation sequencing techniques have enabled the study of genetic variability at specific positions of the viral genome. The present study investigated how 454 pyrosequencing could help unravel intra-host genetic diversity patterns on the full-length viral hæmagglutin...
Sales KG, Costa PL, de Morais RC, Otranto D, Brandão-Filho SP, Cavalcanti Mde P, Dantas-Torres F.Phlebotomine sand flies are blood-feeding insects of great medical and veterinary significance acting as vectors of Leishmania parasites. Studying the blood-feeding pattern of these insects may help in the understanding of their interactions with potential reservoir hosts of Leishmania parasites. In this study, we developed real time PCR assays for the identification of sand fly blood meal. Methods: Six pairs of primers were designed based on cytochrome b gene sequences available in GenBank of the following potential hosts: dog, cat, horse, chicken, black rat, and human. Firstly, SYBR Green-ba...
MacDonald DG, Morley PS, Bailey JV, Barber SM, Fretz PB.Post operative surgical wound infection rates were determined 452 cases of equine orthopaedic surgery performed at the Western College of Veterinary Medicine, Saskatoon, Saskatchewan, between January 1, 1981 and December 31, 1990. Only surgical procedures classified as clean or clean-contaminated by the National Research Council were included in this study. The overall post operative infection rate was 10.0% (45 of 452). Clean surgeries (n = 433) had an 8.1% infection rate while clean-contaminated surgeries (n = 19) had a 52.6% infection rate. Information collected from the medical records was...
Edington N, Bridges CG, Griffiths L.When 23 ponies were infected with equid herpesvirus-1 or -4 (EHV-1 or EHV-4), nasal shedding of interferon (IFN) correlated closely with the duration of viral excretion. Equine interferon (EqIFN) was detected in the serum only from animals infected with the EHV-1 virus, and here high levels correlated with clinical symptoms of locomotor disorder and indicated a poor prognosis. Low levels of IFN were detected in explanted mononuclear cells from ponies infected with either virus.
Anzai T, Eguchi M, Sekizaki T, Kamada M, Yamamoto K, Okuda T.In order to establish a rapid diagnostic method for contagious equine metritis (CEM), we developed and evaluated a polymerase chain reaction (PCR) test. Species-specific PCR primer sets were derived from the DNA sequence of a cloned DNA fragment of Taylorella equigenitalis that did not hybridize with the genome of a taxomonically related species, Oligella urethralis. Single step PCR with primer set P1-N2 and two-step semi-nested PCR with primer sets P1-N2 and P2-N2 detected as low as 100 and 10 CFU of the bacteria, respectively. Single-step PCR detected T. equigenitalis from genital swabs of e...
Niwa H, Hobo S, Kinoshita Y, Muranaka M, Ochi A, Ueno T, Oku K, Hariu K, Katayama Y.Salmonella enterica subsp. enterica serovar Abortusequi is a pathogen restricted to horses. Our investigation targeted 4 draft horses (9-10 months old) kept on a Japanese farm that had suffered an outbreak of S. Abortusequi abortion. The 4 horses were suspected to be carriers of the bacterium owing to their high agglutination titers (≥1:2,560) in tube agglutination testing. The owners' on-farm observations confirmed that the horses had no apparent abnormalities, and S. Abortusequi was not isolated from their blood, rectal swabs, or sternal bone marrow fluid at antemortem investigation. Howev...
Bělková T, Bártová E, Řičařová D, Jahn P, Jandová V, Modrý D, Hrazdilová K, Sedlák K.Theileria equi and Babesia caballi are protozoan agents causing equine piroplasmosis, endemic in countries all over the world. The aim of this study was to detect antibodies to T. equi and B. caballi in horses in the Czech Republic and to investigate the origin of the infection. Blood sera from 711 horses were examined with competitive enzyme-linked immunosorbent assay; positive samples were verified with indirect fluorescence immunoassay. Antibodies to T. equi and B. caballi were detected in eight (1.1%) and three (0.4%) horses, respectively. Infection with T. equi was confirmed by PCR and se...
Thanissery R, McLaren MR, Rivera A, Reed AD, Betrapally NS, Burdette T, Winston JA, Jacob M, Callahan BJ, Theriot CM.The relationship between the gut microbiota and Clostridioides difficile, and its role in the severity of C. difficile infection in humans is an area of active research. Intestinal carriage of toxigenic and non-toxigenic C. difficile strains, with and without clinical signs, is reported in animals, however few studies have looked at the risk factors associated with C. difficile carriage and the role of the host gut microbiota. Here, we isolated and characterized C. difficile strains from different animal species (predominantly canines (dogs), felines (cats), and equines (horses)) that were...
Várady M, Königová A, Corba J.The present study included 19 stud farms, including 243 horses, that were investigated for the occurrence of anthelmintic resistant cyathostomes. The number of horses on the farms varied from nine to more than 100, and horses of all ages were included. A minimum of seven horses were used for faecal egg count reduction (FECR) tests. The anthelmintics included were: fenbendazole (paste formulation), ivermectin (paste formulation) and pyrantel (powder). Resistance to benzimidazoles was detected on 14 farms, with FECR values ranging from 65.1 to 86.3%. Larval cultures after fenbendazole treatment ...
Hannant D, Mumford JA, Jessett DM.The duration of immunity as measured by virological, serological and clinical responses following infection with influenza A/equine/Newmarket/79 (H3N8) was assessed in repeated challenge experiments in which ponies were infected by exposure to aerosols of infectious virus. Previous infection stimulated complete clinical protection which persisted for at least 32 weeks as demonstrated by the absence of febrile responses and coughing in two groups of ponies infected 16 weeks or 32 weeks after the first infection. Partial clinical protection persisted for over a year as demonstrated by the absenc...
Chipangura JK, Chetty T, Kgoete M, Naidoo V.The continuous increase in prevalence of antimicrobial resistant bacteria presents a significant public health problem and is an indicator that antimicrobial prudent usage guidelines are not being followed, especially in developing countries. Despite trends being available from numerous countries, there is little published for South Africa. This study was aimed at estimating the prevalence and trends of antimicrobial resistance from bacterial isolates from equine clinical samples submitted for culture and susceptibility testing to the veterinary bacteriology laboratory of the University of Pre...
Duquesne F, Pronost S, Laugier C, Petry S.A direct-PCR assay was developed for the rapid detection of Taylorella equigenitalis, a Gram-negative bacterium responsible for contagious equine metritis (CEM) in Equidae. The bacteria may be detected in equine genital swabs without need for a preliminary step of DNA extraction or bacterial isolation. Specificity was determined with 125 isolates of T. equigenitalis, 24 isolates of Taylorella asinigenitalis, five commensal bacteria of the genital tract and a facultative intracellular pathogen of foals found in large concentration in soil. Our PCR is specific and amplified a 413-bp 16S ribosoma...
Lakos A, Kőrösi A, Földvári G.Tick-borne lymphadenopathy (TIBOLA) is an emerging infection caused by Rickettsia slovaca. We describe here the seasonal, age and gender characteristics as well as the association with horse contact as risk factors for acquiring TIBOLA in comparison with another, more frequent tick-borne disease, Lyme borreliosis.We analysed a dataset of 855 patients diagnosed with either Lyme (n = 805) or TIBOLA (n = 50) disease using Fisher's exact tests and generalized linear models. Then we performed a matched case-control study in which all TIBOLA patients were paired with one Lyme patient matching in age...
Wu W, Blythe DC, Loyd H, Mealey RH, Tallmadge RL, Dorman KS, Carpenter S.Two variants of equine infectious anemia virus (EIAV) that differed in sensitivity to broadly neutralizing antibody were tested in direct competition assays. No differences were observed in the growth curves and relative fitness scores of EIAVs of principal neutralizing domain variants of groups 1 (EIAV(PND-1)) and 5 (EIAV(PND-5)), respectively; however, the neutralization-resistant EIAV(PND-5) variant was less infectious in single-round replication assays. Infectious center assays indicated similar rates of cell-to-cell spread, which was approximately 1,000-fold more efficient than cell-free ...
Kambayashi Y, Bannai H, Tsujimura K, Hirama A, Ohta M, Nemoto M.In 2020, an outbreak of equine coronavirus (ECoV) infection occurred among 41 horses at a riding stable in Tokyo, Japan. This stable had 16 Thoroughbreds and 25 horses of other breeds, including Andalusians, ponies and miniature horses. Fifteen horses (37 %) showed mild clinical signs such as fever, lethargy, anorexia and diarrhoea, and they recovered within 3 days of onset. A virus neutralization test showed that all 41 horses were infected with ECoV, signifying that 26 horses (63 %) were subclinical. The results suggest that subclinical horses played an important role as spreaders. A genome ...
Bai B, Wang XF, Zhang M, Na L, Zhang X, Zhang H, Yang Z, Wang X.Tetherin is an interferon-inducible type II transmembrane glycoprotein which inhibits the release of viruses, including retroviruses, through a "physical tethering" model. However, the role that the glycosylation of tetherin plays in its antiviral activity remains controversial. In this study, we found that mutation of N-glycosylation sites resulted in an attenuation of the antiviral activity of equine tetherin (eqTHN), as well as a reduction in the expression of eqTHN at the plasma membrane (PM). In addition, eqTHN N-glycosylation mutants colocalize obviously with ER, CD63, LAMP1 and endosome...
Minke JM, Toulemonde CE, Dinic S, Cozette V, Cullinane A, Audonnet JC.A classical limitation of early life immunization is the interference by maternally derived antibodies, which are known to inhibit the immune response to modified-live and killed vaccines. Several studies have convincingly shown that even minute amounts of maternally derived antibodies against equine influenza can strongly interfere with successful vaccination of foals born to immune mares. In this study we evaluated the response of foals born to vaccinated mares to immunization with a canarypox-vectored recombinant vaccine against equine influenza virus H3N8. The recombinant vaccine was able ...
Quintana AM, Hussey SB, Burr EC, Pecoraro HL, Annis KM, Rao S, Landolt GA.To evaluate whether an equine-derived canine H3N8 influenza A virus was capable of infecting and transmitting disease to ponies. Methods: 20 influenza virus-seronegative 12- to 24-month-old ponies. Methods: 5 ponies were inoculated via aerosol exposure with 10(7) TCID(50) of A/Canine/Wyoming/86033/07 virus (Ca/WY)/pony. A second group of 5 ponies (positive control group) was inoculated via aerosol exposure with a contemporary A/Eq/Colorado/10/07 virus (Eq/CO), and 4 sham-inoculated ponies served as a negative control group. To evaluate the potential for virus transmission, ponies (3/inoculatio...
Fortier G, Pronost S, Miszczak F, Fortier C, Léon A, Richard E, Van Erck E, Thiry E, Lekeux P.During a case control study undertaken in 2006-2007, a screening and consensus polymerase chain reaction (PCR) was performed to evaluate the potential role of equid herpesviruses (EHV) in several occurrences of respiratory disorders in 661 horses. Of 785 bronchoalveolar or tracheal lavage fluid samples submitted for analysis, 20 were positive for EHV-5 DNA by sequential analysis of the consensus PCR product. Nineteen of those samples were confirmed using a specific EHV-5 PCR. No particular changes in cytological profile could be associated with the detection of EHV-5 in contrast to suggestions...
Glaser A.Before the introduction of the West Nile virus (WNV) into the United States of America (USA) in 1999, conditions in North America were ideal for an arboviral epidemic. Such factors as the large, susceptible and non-immune animal and human populations, the presence of competent vectors, increasing international travel and commerce, existing methods for rapid dissemination and an ill-prepared animal and public health infrastructure all combined to create the essential elements for a severe animal and public health crisis--the 'perfect microbial storm'. The introduction of WNV into New York City ...
Kuttler KL, Zaugg JL, Gipson CA.The therapeutic efficacies of imidocarb and parvaquone were tested against Babesia equi of European origin in carrier horses and for induced acute infections in splenectomized ponies. Imidocarb, at a dosage of 4 mg/kg of body weight, given IM at 72-hour intervals 4 times, was ineffective in eliminating B equi-carrier infection in 9 mature geldings. A single IM administration of 4 mg/kg was not therapeutic in acutely infected splenectomized ponies. When given at 3 different dosages and treatment schedules, parvaquone was ineffective in clearing carrier infection. Parvaquone given IM once at a d...
Moyaert H, Decostere A, Vandamme P, Debruyne L, Mast J, Baele M, Ceelen L, Ducatelle R, Haesebrouck F.Gram-negative, curved, motile bacteria (strains EqF1T and EqF2) were isolated from faecal samples from two clinically healthy horses. Both strains possessed a single, monopolar, sheathed flagellum and were urease-negative. The novel strains grew at 37 degrees C under microaerobic conditions and were positive for oxidase, catalase and alkaline phosphatase activities. The isolates reduced nitrate to nitrite, but gamma-glutamyl transpeptidase activity was not detected. The novel isolates did not grow at 42 degrees C or on media containing 1 % glycine. They were resistant to cephalotin and nalidix...
Watts DM, LeDuc JW, Bailey CL, Dalrymple JM, Gargan TP.Serological data accumulated during the past decade indicated that a variety of feral and domestic animals of the Delaware-Maryland-Virginia (DelMarVa) Peninsula were infected with Jamestown Canyon (JC) and/or Keystone (KEY) viruses (Bunyaviridae, California serogroup). Neutralizing (N) antibody to JC virus was most prevalent in white-tailed deer, sika deer, cottontail rabbits and horses. KEY virus N antibody was detected most frequently in gray squirrels and domestic goats. N antibody indicative of past infection by one or both viruses also was found in raccoons, horses and humans. JC and/or ...
Goodwin D, Gennari SM, Howe DK, Dubey JP, Zajac AM, Lindsay DS.Encephalitozoon cuniculi has been associated with natural cases of abortion and stillbirth in horses. However, little is known about the prevalence of this parasite in horses. We examined sera from 559 horses from Brazil for antibodies to E. cuniculi using the indirect immunofluorescent antibody (IFA) test and the direct agglutination test (DAT). We found that 79 (14.1%) were positive in the IFA test and 70 (12.5%) were positive in the DAT. Compared to the IFA as the "gold standard" the sensitivity of the DAG was 94.0% and the specificity was 96.1%. Our study indicates that horses in Brazil ar...
Ellison SP, Omara-Opyene AL, Yowell CA, Marsh AE, Dame JB.A gene encoding a major 29 kDa surface antigen from Sarcocystis neurona, the primary causative agent of equine protozoal myeloencephalitis (EPM), was cloned, sequenced, and expressed as a recombinant protein. A cDNA library was prepared in the expression vector lambda ZAP from polyA+mRNA isolated from S. neurona merozoites cultivated in vitro. Random sequencing of 96 clones identified a clone of an abundant transcript having a translated amino acid sequence with 30% identity to the 31-kDa surface antigen of Sarcocystis muris cyst merozoites. Southern blot analysis indicated that the correspond...
Furr M, Howe D, Reed S, Yeargan M.Diagnosis of equine protozoal myeloencephalitis (EPM) remains a challenge for equine practitioners. Current utilized methods have inadequate sensitivity and specificity, because of a high number of false positive results. Objective: Evaluation of antibody indices to Sarcocystis neurona should provide high sensitivity and specificity for diagnosis of EPM. Methods: Archived samples from 29 clinical patients. Methods: Archived serum and cerebrospinal fluid (CSF) samples from clinical patients with either EPM (14) or cervical vertebral compressive myelopathy (CVM) (15) were examined and tested for...
George JL, Reif JS, Shideler RK, Small CJ, Ellis RP, Snyder SP, McChesney AE.During an outbreak of strangles in a population of research horses, 4 mares were identified as carriers of Streptococcus equi. Three of the mares had typical signs of strangles (severe regional lymphadenitis with or without rupture of abscessed lymph nodes). The 4th mare experienced episodes of serous to mucopurulent nasal discharge, but never had more than a mild degree of lymph node enlargement. Streptococcus equi was isolated from the abscessed lymph nodes and from nasopharyngeal swab specimens from the first 3 mares from 6 to 19 weeks after rupture of involved nodes. Streptococcus equi was...
Daly J, Daas A, Behr-Gross ME.In 2004, the Office International des Epizooties (OIE) Expert Surveillance Panel on equine influenza recommended that the American lineage component (H3N8) of equine influenza vaccines (A/eq/Newmarket/1/93-like) be updated to an A/eq/South Africa/4/03-like virus. As a consequence the common European Pharmacopoeia (Ph. Eur.) - OIE reference for equine influenza subtype 2 American-like antiserum had to be complemented by an antiserum raised in horses against an A/eq/South Africa/4/03 strain. An international collaborative study run by the European Directorate for the Quality of Medicines (EDQM) ...
Haliburton JC, Vesonder RF, Lock TF, Buck WB.Signs and lesions characteristic of equine leucoencephalomalacia were produced in one of two donkeys given corn cultured with Fusarium moniliforme Sheldon. Gross and histopathologic lesions of the cerebrum included an extensive necrotic cavitation within one cerebral hemisphere, disruption and rarefication of the subcortical white matter, prominent perivascular hemorrhage, and some mononuclear cell perivascular cuffing. Another donkey and three rabbits fed the cultured corn did not develop characteristic signs or lesions of the toxicosis. Chick bioassay studies indicated that the cultured corn...
Garcia-Etxebarria K, Jugo BM.Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have become incorporated into the host genome. Little is known about ERVs in the horse genome. By combining 3 bioinformatic approaches, we detected 1947 putative ERVs in the horse genome. These equine ERVs are not scattered randomly across the genome and are especially abundant in the X chromosome. Based on phylogenetic relationships, some of these equine ERVs were classified into 15 previously uncharacterized families of Classes I, II and III. Compared with the cow and other species, the horse genome appears to ...
Raisis AL, Hodgson JL, Hodgson DR.Equine neonatal septicaemia was confirmed in 24 foals hospitalised at the Rural Veterinary Centre between 1989 and 1992 with suspected septicaemia. Septicaemia was confirmed by culture of bacteria from blood of live foals and tissues obtained at necropsy of foals that died or were euthanased. Pathogenic bacteria isolated were predominantly Enterobacteriaceae (including Escherichia coli and Salmonella serovars) and Actinobacillus equuli. Clinical manifestations of septicaemia included signs of depression, dehydration, abnormalities in body temperature and manifestations of localised infection i...
Wilson ME, Holz CL, Kopec AK, Dau JJ, Luyendyk JP, Soboll Hussey G.Equine herpesvirus type 1 (EHV-1) is the cause of respiratory disease, abortion storms, and outbreaks of herpesvirus myeloencephalopathy (EHM). Infection of the spinal cord is characterised by multifocal regions of virally infected vascular endothelium, associated with vasculitis, thrombosis and haemorrhage that result in ischaemia and organ dysfunction. However, the mechanism of thrombosis in affected horses is unknown. Objective: To evaluate tissue factor (TF) procoagulant activity and thrombin-antithrombin complex (TAT) levels in horses following infection with EHV-1. Methods: In vitro and ...
