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.
Ross MW, Stephens PR, Reimer JM.A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosi...
Sundquist B, Lövgren K, Morein B.A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Mendoza L, Alfaro AA, Villalobos J.A 5-year-old, female saddle horse developed a tumoral mass anterolaterally on the metacarpal region of its right front leg. Histopathological study showed hyaline, aseptate, broad hyphae in the sequestered coral-like necrotic masses. Radiographs revealed an extensive osteomyelitis with disorganized bone proliferation of the metacarpal bones, as well as exostosis of the distal radius and the proximal and distal row of carpal bones. The etiologic agent was detected histologically, isolated in culture and identified as Pythium insidiosum. Serological tests were positive. Immunotherapy was applied...
Bridges CG, Ledger N, Edington N.Ponies, without evidence of previous exposure to Equine herpes virus-1 (EHV-1), were experimentally infected with EHV-1 subtype 2 and investigated for lymphocyte transformation to virus-infected cell polypeptides, as shown by separation with gel electrophoresis. Animals made significant responses to Western blot fractions that corresponded to molecular weights of approximately 30,000, 40,000-45,000, 60,000-65,000, 80,000-95,000 and 100,000-140,000 MW. These molecular weight ranges correlated with the positions of major EHV-1 subtype 2 glycoproteins that were found at migration distances approx...
Belknap J, Arden W, Yamini B.A 2-month-old Standard-bred colt with signs of abdominal pain and large scrotum was found to have septic periorchitis involving the right testis. Surgical exploration of the abdomen and scrotum was performed; the colt was then castrated. Actinobacillus equuli was isolated from specimens obtained at surgery. The colt was treated with broad-spectrum antibiotics and flunixin meglumine after surgery, and fully recovered. The clinical signs of periorchitis in the colt were similar to an inguinal/scrotal hernia.
Plenderleith RW.In large animal practice, clinical cases involving deep-seated infections affecting bones, joints, meninges and the larynx are particularly difficult to treat. The antibiotic lincomycin has the ability to penetrate tissue of poor vascularity and is also effective in the presence of pus. Eleven cattle, six sheep and three horses were treated with the drug at various doses and in 75 per cent of the cases there was a positive response.
Lyons ET, Drudge JH, Tolliver SC.During 1986, fecal specimens were collected 1 or more times from each of 164 horse foals (158 Thoroughbred and 6 mixed light horse type), ranging in age from 0 to 252 days, on 13 farms in central Kentucky. To detect natural infection with Eimeria leuckarti, feces were examined for oocysts. Oocysts were found in 67 (41%) of the foals on 11 (85%) of the farms. The earliest age at which oocysts were first detected was 15 days (1 foal); the latest age was 123 days (1 foal). The mean age for the first appearance of oocysts in the feces of the 67 foals positive for E leuckarti was approximately 70 d...
Cabañes FJ, Abarca L, Bragulat MR, Bruguera T.A phaeohyphomycotic infection caused by Alternaria alternata is reported in a 5-month-old Spanish mare. The diagnosis was made by direct microscopic examination and by repeated isolation of the fungus in culture. This is the first documented case to be reported in Spain.
Peterson RB, Goyal SM.A comparative study was carried out to determine the relative sensitivities of eight different cell culture systems to six different herpesviruses of animals. The cells used were: OFL (ovine fetal lung), ML (mink lung), FK (ferret kidney), PTK-2 (potoroo kidney), TEK (turkey embryo kidney), ED (equine dermal), BT (bovine turbinate), and PK15 (porcine kidney). The viruses tested were: PRV (pseudorabies) of swine, CPHV (caprine herpesvirus), IBRV (infectious bovine rhinotracheitis virus), DN-599 strain of bovine herpesvirus type 4, EHV-1 (equine herpesvirus), and CHV (canine herpesvirus). On the...
Brewer BD, Koterba AM.A sepsis scoring system was developed and tested prospectively in a blind study of 190 neonatal foals admitted to the University of Florida Veterinary Medical Teaching Hospital's neonatal intensive care unit. The system used 14 readily available historical, clinical or laboratory variables and weighted each item to arrive at a sepsis score. The score was found to have a sensitivity of 93 per cent, a specificity of 86 per cent, positive accuracy rate of 89 per cent and negative accuracy rate of 92 per cent. The sepsis score was far more sensitive and specific for infection, even in very early c...
Bermudez V, Miller RB, Johnson W, Rosendal S, Ruhnke L.The growth of Mycoplasma equigenitalium and Mycoplasma subdolum from specimens collected from the clitoral fossa of each of four Standardbred mares was not diminished by freezing of the specimens in liquid nitrogen (-196 degrees C) for up to 30 days when compared to samples cultured immediately.
Thein P, Brown K.Infections with EHV1 can lead to manifestation at the CNS of horses followed by encephalomyelitis and "equine stroke". Horse experiments could confirm the clinical picture and gave links to the potential pathogenesis of the disease. We also have been in the position to isolate and characterize an EHV4 virus out of the brain of a horse with CNS disorders. The two viruses carry different biological properties which obviously dominate the pathogenesis. These properties as well as experimental and field cases are described and different diagnostic tests are discussed.
Browning GF, Ficorilli N, Studdert MJ.Two previously unknown and distinct herpesviruses were isolated from donkeys. One, with the characteristics of a betaherpesvirus, was isolated from the leukocytes of an apparently healthy donkey, while the second, an alphaherpesvirus, was recovered from the nasal cavity of donkeys given high doses of corticosteroids, and caused rhinitis in two seronegative weanling donkeys when they were intranasally infected. Few, if any, restriction endonuclease fragments were shared by the donkey betaherpesvirus, equine herpesvirus 2 (EHV 2) or EHV 5, a second distinctly different equine betaherpesvirus, no...
Adams R, Koterba AM, Cudd TC, Baker WA.The medical records of 18 neonatal foals, in which exploratory celiotomies were performed for suspected urinary tract lesions, were reviewed. Despite clinical signs and laboratory values indicative of disruption of the urinary tract, three foals did not have a site of urinary tract leakage at surgery. Eight foals had ruptured bladders and seven foals had urachal lesions. Ultrasonography was used as a pre-operative diagnostic procedure in eight foals to evaluate the presence of free peritoneal fluid and urinary tract integrity. Nine foals were alive six months after discharge. Seven of the nine...
Bosler EM, Cohen DP, Schulze TL, Olsen C, Bernard W, Lissman B.By using paired sera the IgM and IgG host responses were analyzed in dogs with ELISA and Western blot techniques. Antibodies in clinical seropositive dogs bound to 4-25 IgM and up to 40 or more IgG antigenic determinants. Early IgM response to the 41-kDa flagellin persisted for at least 9 months and involved as many as seven other peptides. IgG response expanded later in the disease and involved more immunogens than are currently recognized in late human disease. A percentage of asymptomatic dogs that later developed clinical symptoms were seropositive. Immunoblot studies suggested that B. bur...
Gold JJ, Heath IB, Bauchop T.Vegetative and reproductive stages of Caecomyces equi gen. nov., sp. nov. isolated from the horse caecum were examined by light and electron microscopy. This organism, which is similar to isolates known as Sphaeromonas communis, produces uniflagellate, uninucleate zoospores whose perikinetosomal structures, i.e. circumflagellar ring, spur, struts and scoop, are similar in many respects to those described in species of Neocallimastix. Microtubular roots extend basally from the spur and associate with hydrogenosomes and the nucleus. Another group of microtubules radiates laterally in a fan-shape...
Jaeschke G, Wintzer HJ.This is a review on Morbus maculosus equorum (purpura haemorrhagica) on the base of literature data and of a case report on 13 own patients. It is shown, that the clinical picture of this disease has not changed within the last 150 years. Clinical main symptoms are haemorrhagic diathesis (petechiae, ecchymosis, suggillations) as well as peripheral edema and fever. The main haematological findings are neutrophilia, mostly going along with shift to the left and lymphopenia. In the last few years thrombocytopenia was also described in some cases. Basic therapeutics are glucocorticoids and penicil...
Kuttler KL, Goff WL, Gipson CA, Blackburn BO.Both the complement-fixation test (CFT) and the indirect fluorescent antibody test (IFAT) were conducted on weekly serum samples from nine Arab geldings for 28 days before and 256 days after their exposure to Babesia equi of European origin. On an average the IFAT became positive 8 days before the CFT and showed higher relative serum titer increases. Both test procedures successfully detected infection and neither showed an appreciable drop in titer during this time frame, with the exception of the CFT, which showed a transient drop immediately following treatment with imidocarb. A test conduc...
Cohen D, Bosler EM, Bernard W, Meirs D, Eisner R, Schulze TL.A serologic survey of horses in the New Jersey-Pennsylvania area demonstrated that about 10% (6.2-14.2%) have significant levels of serum antibody to Borrelia burgdorferi. However, in a highly endemic area of central New Jersey, up to 60% of the mares and yearlings samples on one farm were seropositive. In 1983, sera from this same farm exhibited only 12% positives in mares and 35% positives in yearlings. Longitudinal studies of paired sera obtained from individual yearlings over a 6-month period in 1985 showed that 34% of them declined during the period. A new clinical syndrome associated wit...
Murakami Y, Nerome K, Yoshioka Y, Mizuno S, Oya A.Growth characteristics of a wide range of influenza A viruses from different mammals and bird species were examined in an established line of canine kidney (MDCK) cells at an ordinary (37 degrees C) and a high temperature (42 degrees C). Although all viruses employed in the present study possessed a capability of replicating at 37 degrees C, virus growth at 42 degrees C showed considerable variation and reflected differences in the natural hosts of the isolates. All reference strains and isolates from bird species grew well in the MDCK cells maintained at 42 degrees C, but human viruses did no...
Akkmeteli MA.Although mycotoxicoses attract more and more attention, the epidemiology of these diseases is still not adequately studied. The author devotes his study to certain diseases. In addition to the diseases whose mycotoxic nature is in no doubt, he conditionally includes certain diseases whose mycotoxic causation needs further proof. The author has assigned stachybotryotoxicosis and alimentary toxic aleukia or fusariotoxicosis to the first category and endemic nephropathy and primary liver-cell carcinoma to the second. His intention in adopting this approach is to establish the common features and ...
Hall RF, Pursell AR, Cole JR, Youmans BC.An epizootic of equine infectious anemia (EIA) involved 35 horses on a farm in south Georgia. During a 126-day period, 21 of these horses became seropositive for EIA. After the initial diagnosis in July, the horses were tested every 7 to 10 days. At least one additional horse was found to be seropositive on each testing day. As soon as they were determined to be seropositive, the horses were removed from the herd and sent to slaughter. The removal of the seropositive horses, however, did not stop the epizootic. We believe the initial infection was from a 7-year-old stallion that recently had b...
Dorr TE, Higgins RJ, Dangler CA, Madigan JE, Witham CL.Three cases of equine protozoal myeloencephalitis were diagnosed over a 12-month period in horses that had never left the state of California. These cases suggest that the disease is enzootic in California.
Padilla SL, Prieto K, Dohm DJ, Turell MJ, Klein TA, Fernández R, Watts DM, Lowen RG, Palacios GF, Pitt ML, Wiley MR, Nasar F.Venezuelan equine encephalitis virus (VEEV) is an important pathogen of medical and veterinary importance in the Americas. In this report, we present the complete genome sequences of five VEEV isolates obtained from pools of Culex (Melanoconion) gnomatos (4) or Culex (Melanoconion) pedroi (1) from Iquitos, Peru. Genetic and phylogenetic analyses showed that all five isolates grouped within the VEEV complex sister to VEEV IIIC and are members of subtype IIID. This is the first report of full-length genomic sequences of VEEV IIID.
Penell JC, Bonnett BN, Pringle J, Egenvall A.Computerized diagnostic information offers potential for epidemiological research; however data accuracy must be addressed. The principal aim of this study was to evaluate the completeness and correctness of diagnostic information in a computerized equine clinical database compared to corresponding hand written veterinary clinical records, used as gold standard, and to assess factors related to correctness. Further, the aim was to investigate completeness (epidemiologic sensitivity), correctness (positive predictive value), specificity and prevalence for diagnoses for four body systems and cor...
Seahorn JL, Slovis NM, Reimer JM, Carey VJ, Donahue JG, Cohen ND.To identify factors significantly associated with an epidemic of fibrinous pericarditis during spring 2001 among horses in central Kentucky. Methods: Case-control study. Methods: 38 horses with fibrinous pericarditis and 30 control horses examined for other reasons. Methods: A questionnaire was developed to solicit information regarding a wide range of management practices and environmental exposures from farm owners or managers. Results: The following factors were found in bivariate analyses to be significantly associated with an increased risk of pericarditis: being from a farm with mares an...
London WT, Levitt NH, Altshuler G, Curfman BL, Kent SG, Palmer AE, Sever JL, Houff SA.Fetal rhesus monkeys were inoculated intracerebrally with an attenuated strain of western equine encephalitis virus. All animals developed microcephaly. Twelve of sixteen monkeys developed ex vacuo hydrocephalus. All virus inoculated fetuses developed WEE virus antibody. Virus could not be recovered at the time of delivery. Monkeys with the highest WEE antibody titers showed the greatest degree of hydrocephalus.
The goal of this work was the development of suitable (real-time) RT-PCR techniques for fast and sensitive diagnosis of EAV and for molecular-epidemiological characterisation of viral strains, as an alternative to virus isolation. To this purpose two conventional RT-PCR methods and one real-time RT-PCR were adapted to detect the broadest possible spectrum of viral strains. Several dilutions with Bucyrus strain showed a 100-fold higher sensitivity of real-time RT-PCR and heminested RT-PCR compared to simple RT-PCR. Making use of 11 cell culture supernatants of different EAV isolates and 7 semen...
Hughes K.Cases of Hendra virus infection in horses in Australia have been seen regularly since the virus was first isolated in 1994. Kristopher Hughes, associate professor of equine medicine at Charles Sturt University in Australia, gives an overview of how knowledge of the virus has developed in the past 20 years.
Boucher C, Higgins R, Nadeau M, Vincent C.A sexagenarian couple operating a dairy farm, where there were also many horses, suffered a severe respiratory infection associated with the bacterium Streptococcus equi ssp. zooepidemicus. The investigation revealed that the source of infection was due to contacts with a horse having an infected wound from which we isolated this zoonotic agent. A sexagenarian couple operating a dairy farm, where there were also many horses, suffered a severe respiratory infection associated with the bacterium Streptococcus equi ssp. zooepidemicus. The investigation revealed that the source of infection was du...
Ardans AA, Pritchett RF, Zee YC.A viral agent was isolated from lung tissue obtained upon necropsy of an Arabian foal which had exhibited clinical signs of pneumonia. The virus is 75 nm in diameter, cubic in symmetry, and resistant to chloroform and low pH (3.0). It contains deoxyribonucleic acid and has a buoyant density of 1.31 g/cm(3) in cesium chloride. These findings indicate that the virus is a member of the adenovirus group.
Sullivan E, Lecollinet S, Kerviel A, Hue E, Pronost S, Beck C, Dumarest M, Zientara S, Roy P.African horse sickness virus (AHSV) is an Orbivirus within the Reoviridae family, spread by Culicoides species of midges, which infects equids with high mortality, particularly in horses and has a considerable impact on the equine industry. In order to control the disease, we previously described Entry Competent Replication Abortive (ECRA) virus strains for each of the nine distinct AHSV serotypes and demonstrated their potential as vaccines, first in type I interferon receptor (IFNAR-/-) knockout mice, and then in ponies. In this report we have investigated whether or not a combination ECRA v...
Eyre P, Gaviller P, Thorsen J.Groups of guinea-pigs were vaccinated with equine influenza A-1 virus and helically-cut tracheal strips were subsequently contracted to carbachol (EC50) and relaxed to isoprenaline at 3, 5 and 10 days post-vaccination. Tracheas from another group were contracted to phenylephrine in the presence of propranolol. Compared to controls, responses to isoprenaline in virus-infected tracheas were significantly potentiated at days 3 and 10. Virus infection significantly inhibited tracheal responsiveness to phenylephrine. It appears that enhancement of isoprenaline may be caused by diminished reactivity...
How SJ, Lloyd DH, Lida J.A monoclonal antibody (McAb) to Dermatophilus congolensis was produced from murine hybridoma cultures and purified by affinity chromatography. Species specificity was demonstrated using indirect immunofluorescent staining; the McAb was shown to react with 10 D congolensis isolates but not with 10 Nocardia species isolates, a Rhodococcus and a Streptomyces species isolate. The McAb was used to demonstrate D congolensis in clinical material from confirmed bovine and ovine cases and presumptive equine cases of dermatophilosis by indirect immunofluorescent staining.
Kalinowski M, Grądzki Z, Jarosz Ł, Adaszek Ł.Rhodococcus equi (R. hoagii) is an opportunistic pathogen commonly found in foals up to 6 months old and animal environment. The R. equi genome contains genetically stable chromosomal DNA and an 80-90 kb plasmid containing vapA gene, responsible for virulence. Most reports from around the world focus on the determination of R. equi plasmid profiles. Few studies have attempted to determine differences in nucleotide sequences between virulent strains of R. equi isolated from foals and breeding environment. The aim of the study was to perform a molecular analysis of a fragment of the chromosomal ...
Adeyefa CA.The effects of the various growth factors with regard to the nutritional physiology of zoophilic dermatophytes isolated from horses are reported. The optimum temperature, pH and growth period for the fungal isolates were found to be 30 degrees-35 degrees C, 5-6 and 7-12 days respectively while the carbon and nitrogen sources utilised by the organisms were sucrose, fructose, maltose, L-arginine and calcium nitrate. The use of these factors in preparation of efficacious fungicides used in the treatment of ringworm infections in man and animals is discussed.
Buchwalder R, Schuster R.For the first time findings of Setaria equina (Abildgaard, 1789) in horses are reported from the German Democratic Republic. The nematodes, located in the peritoneum, were discovered in the course of autopsy. Based on a thorough analysis of the international literature, the paper discusses geographical distribution, morphology, cycle and diagnosis of this nematode as well as clinical symptoms mainly caused by the stages of the larvae.
Chambers TM, Reedy SE.In horses, presumptive diagnosis of equine influenza is commonly made on the basis of clinical signs. This alone is insufficient for confirmation of equine influenza, because other equine infectious respiratory diseases can in some degree have similar clinical presentations. Surveillance and control of equine influenza also necessitate detection of subclinical cases. Effective diagnosis of equine influenza virus infection is critically dependent on obtaining adequate specimens of virus-containing respiratory secretions for testing. These specimens are also valuable as sources for isolation of ...
During 2013, in Argentina, three new isolates of serogroup Bunyamwera virus (genus Orthobunyavirus, family Peribunyaviridae) were recovered from two horses with encephalitis, and from an aborted equine fetus. In the present study, we report the complete genome sequence, genetic characterization, and phylogenetic analysis of three new strains isolated in Argentina to clarifying their relationship within the Bunyamwera serogroup virus and to investigate the evolutionary history of viruses with segmented genomes.
Saengseesom W, Kasempimolporn S, Akesowan S, Ouisuwan S, Sitprija V.A therapeutic anti-rabies immunoglobulin for human use has been produced mainly in horses. The presently available seroneutralization test, the rapid fluorescent focus inhibition test (RFFIT), is laborious and rather difficult to carry out in horse farms. This study was undertaken to develop a simple latex agglutination test (LAT) for determining rabies antibodies in horse sera. LAT was validated by testing a total of 468 horse serum samples characterized by RFFIT. Of these, 253 of 260 samples with antibody titers of less than 100 IU/ml had agglutination score of 1+, whereas 174 of 208 samples...
Jaspers U, Thiele D, Krauss H.A competitive ELISA system for the detection of antibodies against Coxiella (C.) burnetii in cattle, sheep, goats, horses and humans is described. The ELISA is based on a biotinylated monoclonal antibody with specificity for C. burnetii lipopolysaccharide in combination with streptavidin peroxidase. For evaluation and statistical analysis, 413 sera from cattle, sheep, goats, horses and humans were tested in parallel in the indirect immunofluorescence test (IFT). Furthermore, a total of 448 bovine and human sera were also tested with an indirect ELISA and 47 sheep sera were investigated using t...
Ward AC, Sriranganathan N, Evermann JF, Traub-Dargatz JL.Escherichia coli was isolated from the feces and intestines of foals with and without diarrhea. Piliation of isolates was demonstrated by electron microscopy and agglutination in antisera having specificity for K88, K99, P987 and F41 pili. Piliation was also demonstrated by electron microscopy on organisms which did not react with any of the antisera.
Among the protozoa of the genus Sarcocystis (Apicomplexa; Sarcocystidae), Sarcocystis bertrami (syn. Sarcocystis fayeri) is an obligate intracellular parasite of donkeys and horses with worldwide distribution. Here, we report the detection of S. bertrami in naturally infected donkeys from southern Italy and describe their structure by light microscopy (LM) and transmission electron microscopy (TEM). Protozoal cysts were detected both morphologically and molecularly in skeletal muscles of 28.57% (40/140) donkeys. Mature cysts of S. bertrami were found in skeletal muscle measuring 31-102 μm l...
Sahu SP, Dardiri AH, Rommel FA, Pierson RE.Survival of bacteria that cause contagious equine metritis (CEM) was evaluated in Amies modified transport (AMT) medium, in AMT medium with charcoal, and in Stuart transport medium at 37, 22, 4, and -70 C. The CEM bacteria suspended in transport media survived at 22, 4, and -70 C for longer periods in AMT medium with charcoal than they did in AMT and Stuart transport media. In 1 day, the number of bacteria in exudate stored in the absence of any transport medium decreased 15-fold at 22 C and twofold at 4 C. The CEM bacteria were isolated from exudate on cotton-tipped swabs from all three trans...
Clayton YM, Fox EC.The research article aims to investigate the mycology of dental calculus (tartar) and its potential to harbor fungal organisms that could lead to ocular infections, particularly in those involved in […]
Thornton JJ, Roberts JF, AuCoin DP, Tuanyok A.We report a presumptive case of melioidosis caused by an atypical Burkholderia pseudomallei serotype in an American quarter horse in north-central Florida, USA, through archived formalin-fixed paraffin-embedded specimens dating back to 2006. This case underscores the potential pathologic impact of emergent B. pseudomallei in the Gulf region of the United States.
Ganbaatar O, Ganzorig S, Tseren-Ochir EO, Suzuki Y, Takai S.In 2024, 90 soil samples and 11 fecal samples were collected from nine Mongolian provinces. Using NANAT selective agar, R. equi was successfully isolated from 23 soil samples (25.6%) across five provinces and from three fecal samples (27.3%) collected in two provinces. A total of 122 isolates were identified as R. equi via choE-targeted polymerase chain reaction (PCR) and subsequently screened for virulence-associated genes (vapA, vapB, and vapN) by PCR. Of these, 17 isolates tested positive for the vapA gene, while the remaining 105 isolates were negative for both vapB and vapN. Plasmid prof...
Kirisawa R, Hosoi Y, Yamaya R, Taniyama H, Okamoto M, Tsunoda N, Hagiwara K, Iwai H.We isolated a variant equine herpesvirus-1 (EHV-1), strain 5089, from the lung of a dead neonatal foal in Japan and characterized the biological nature of the virus. The virus spread in cultured cells mainly by cell-to-cell infection, unlike wild-type EHV-1, which spreads efficiently as a cell-free virus. The virus titer in cultured supernatant and the intracellular virus titer were low compared to those of wild-type EHV-1. Heparin treatment of the virus had no effect on viral infectivity in cell culture. Glycoprotein C (gC) was not detected by Western blotting and fluorescent antibody tests i...
