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.
Lane JG, Gibbs C, Meynink SE, Steele FC.The radiographic procedures used for examination of the facial area and paranasal sinuses of 235 horses are reported. Clinical indications for these examinations and the diagnoses made are reviewed. Unilateral nasal discharge was the commonest reason for radiography, accounting for about one third of cases, most of which had radiological signs of paranasal sinus disease recognisable on erect lateral films. Oblique projections were required to obtain further information about the maxillary dental arcades and ventro-dorsal views demonstrated sinus expansion and extension of disease into the nasa...
Morris DD.The medical records of 19 horses with cutaneous vasculitis were reviewed. Most (73.7%) affected horses were between 3 and 10 years old, and there were significantly more mares (14) than stallions or geldings (5) (P less than 0.01). Subcutaneous edema of the limbs, body, and/or head was the predominant clinical sign (18/19 horses; 94.7%). The single most prevalent laboratory abnormality was neutrophilia (greater than 7,000 neutrophils/microliter), which was detected in 10 horses (52.6%). Leukocytoclastic vasculitis was evident in skin biopsy specimens from 12 of 14 horses (85.7%). All horses we...
Madigan JE, Higgins RJ.Equine protozoal myeloencephalitis (EPM) is a disease that produces neurologic signs of brain or spinal cord dysfunction. The causative organism is believed to be a Sarcocystis species of protozoa. A definitive diagnosis can only be made on histopathology of affected spinal cord or brain. No preventive measures or documented treatment is available at this time for suspected cases of EPM.
Barragry TB.The avermectins were introduced in 1981 and constitute a potent new class of anthelmintic agents. They are naturally-derived products of microbial action displaying an exceptionally wide range of antiparasitic efficacy against internal and external parasites of domestic animals. This paper reviews their isolation and chemistry, mechanism of action, chemical efficacy and safety in cattle, sheep, swine, horses and dogs.
Hietala SK, Ardans AA.The interaction of Rhodococcus equi with alveolar macrophages from adult horses, foals experimentally exposed to R. equi (sensitized foals) and non-exposed foals was studied using in vitro bactericidal assays, cytochemical staining and transmission electron microscopy. It was demonstrated that R. equi is a facultative intracellular parasite, able to survive and multiply within the alveolar macrophages of the host by interfering with phagosome-lysosome fusion. Opsonization of R. equi with antibody against capsular components was associated with increased phagosome-lysosome fusion and significan...
Prescott JF.Current understanding of the epidemiology of Rhodococcus equi infection on horse farms is reviewed. Infection is widespread in herbivores and their environment, because herbivore manure supplies the simple organic acid substrates on which the organism thrives. There is a progressive development of infection in the soil on horse farms with prolonged use, because: (1) there is a continual supply of nutrients; (2) the organism multiplies progressively as temperatures rise; (3) the bacterium has a robust nature. While this aerobic organism fails to multiply in the largely anaerobic intestine of th...
Debey MC, Bailie WE.Horse farms in Kansas were surveyed for the incidence of Rhodococcus equi. Fecal specimens and soil or cobweb samples were collected from each farm and cultured on selective media. One control farm (with no history of R. equi infection), one farm which had an outbreak 3 and 4 years previously and 2 farms which had R. equi-infected foals that season were surveyed. In addition, fecal samples from 21 horses hospitalized in the Kansas State University Veterinary Hospital were cultured. There was no significant difference in the incidence of R. equi in fecal samples from the 2 farms with recent dis...
Yager JA, Duder CK, Prescott JF, Zink MC.Polymorphonuclear neutrophil leukocytes (PMNL) from 8 healthy foals (2-14 weeks of age) and 2 foals with bacterial pneumonia were separated from whole blood using a 2 step Percoll gradient. Purified PMNL were tested for bactericidal function against Rhodococcus equi and Staphylococcus aureus in the presence of normal horse serum. The percentage uptake after a 15-min pre-incubation of PMNL and bacteria was also calculated. Ultrastructural examination of the interaction of R. equi and normal foal PMNL was performed after 15 min incubation. Results indicated that foal PMNL effectively phagocytose...
Takai S, Fujimori T, Katsuzaki K, Tsubaki S.Quantitative culture of R. equi in the feces of dams and foals, in the air of the stalls and in the soil of the paddocks was carried out on three horse-breeding farms during the foaling season. The isolation rates of R. equi from the feces of dams from the 3 farms suddenly increased to approximately 80% at the end of March, when the snow in the paddocks finished melting, and remained at that level during April and May. The mean number of R. equi and the isolation rate of R. equi from the feces of dams on the farms were investigated for 5 weeks before and 5 weeks after delivery. During the 10 w...
Yager JA.The pathogenesis of Rhodococcus equi pneumonia in foals is reviewed. The main routes of infection are respiratory and alimentary. The latter is probably the chief route of exposure in all foals and probably leads to development of specific immunity. Susceptible foals, those whose maternal immunity wanes before generation of their own immune response, readily develop disease if exposed aerogenously to sufficient numbers of R. equi. Management and environmental circumstances have a major role to play in determining the magnitude of this challenge and, therefore, in the prevalence of the disease....
Keane DP, Little PB.Rabies, equine herpesvirus type I, and eastern and western encephalomyelitis viruses, known causes of equine neurological disease, are reviewed with emphasis on epidemiology, pathogenesis, clinical signs, and diagnosis.Several arboviruses known to be active in Canada and capable of producing neurological disease in humans (Powassan, St. Louis encephalitis, snowshoe hare, and Jamestown Canyon viruses) are discussed as potential causes of encephalomyelitis in horses.
Hall J, Zha XH, Yu L, Yu CA, Millett F.The interaction of the Rhodobacter sphaeroides cytochrome bc1 complex with Rb. sphaeroides cytochrome c2 and horse cytochrome c was studied by using specific lysine modification and ionic strength dependence methods. The rate of the reactions with both cytochrome c and cytochrome c2 decreased rapidly with increasing ionic strength above 0.2 M NaCl. The ionic strength dependence suggested that electrostatic interactions were equally important to the reactions of the two cytochromes, even though they have opposite net charges at pH 7.0. In order to define the interaction domain on horse cytochro...
Jones RL, Adney WS, Shideler RK.Clostridium difficile was isolated from the feces of 27 of 43 diarrheic foals (63%), and cytotoxin was detected in feces from 28 diarrheic foals (65%). The foals had not received any antimicrobial treatment before the onset of diarrhea. C. difficile was not isolated from feces of 18 normal foals without diarrhea and 62 adult horses (P less than 0.005). This finding of C. difficile and its toxins in association with diarrhea in foals adds another possible cause to the list of infectious agents which may cause diarrhea in foals.
Jang SS, Biberstein EL, Hirsh DC.Actinobacillus suis-like organisms have been recognized in equine specimens at the University of California Veterinary Medical Teaching Hospital since 1975. The most common source (65%) of the organism was transtracheal washings. The organism was gram-negative, produced hemolysis on blood agar, and gave a positive reaction for oxidase, urease, o-nitrophenyl-beta-D-galactopyranoside, and esculin. Carbohydrate reactions were variable, consisting of 4 main patterns. Actinobacillus suis-like organisms were (90%) sensitive to therapeutic concentrations of amikacin, cephalothin, chloramphenicol, gen...
Timoney PJ, McCollum WH, Roberts AW, McDonald MJ.Clinical cases of equine arteritis virus infection have not been diagnosed in Kentucky since 1984, and there has been no indication that any of the horses involved in the 1984 epizootic have since been responsible for spread of the disease to horses in other states or other countries. Cases of abortion caused by naturally acquired infection with this virus have not been confirmed in 1984 or 1985. Neither field nor vaccine strains of equine arteritis virus have been shown to induce teratologic abnormalities or the carrier state in foals born to infected or vaccinated mares. The carrier stallion...
Chirino-Trejo JM, Prescott JF.The antigens extracted from strains belonging to seven capsular serotypes of Rhodococcus equi, as well as from two wild strains isolated from pneumonic foals, were examined. Whole-cell antigens and soluble products present in broth culture supernatants were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroblotted onto nitrocellulose, and stained with serum from hyperimmunized rabbits or foals. Foal sera used included sera from pneumonic animals with known titer to equi factors; from animals bled monthly on a farm with enzootic pneumonia, and from animals bled mont...
McLean RG, Calisher CH, Parham GL.Blood samples collected in September and November 1980 from 87 horses in southwestern Michigan were examined for virus isolation and for plaque-reduction neutralizing antibody against selected arboviruses. Cache Valley virus was isolated from the blood of a clinically normal horse in St Joseph County in September. The age-specific antibody prevalence for Cache Valley virus indicated enzootic transmission in the study area. The high antibody prevalence and the lack of age-specific antibody prevalence indicated sporadic, but intense, exposure to Jamestown Canyon virus. Low prevalences of antibod...
Edwards JF, Yedloutschnig RJ, Dardiri AH, Callis JJ.Virus isolation was attempted from 262 field samples of vesicular material collected during the outbreaks of vesicular exanthema of swine in the U.S.A. from 1952-54. Using primary swine kidney culture, viral cytopathogenic agents were isolated from 76.3% of the samples. However, an overall recovery rate of 82.1% was obtained after samples negative in tissue culture were inoculated intradermally in susceptible swine. All vesicular exanthema of swine virus isolates were identified as serotype B51 using complement fixation and serum neutralization tests. Two isolates did not react with antisera t...
Perdrizet JA, Scott DW.Cellulitis and subcutaneous abscess formation was diagnosed in a 3-month-old Thoroughbred filly. Clinical signs consisted of a large ulcerated plaque, with satellite pustules on the medial aspect of the right hock and subcutaneous abscesses in the right inguinal and mammary gland areas. Laboratory analysis revealed mature neutrophilia. Rhodococcus equi was isolated from the cellulitis and the subcutaneous abscess. Oral administration of erythromycin and rifampin for 35 days resulted in a clinical cure.
Blue J, Perdrizet J, Brown E.Acute myelomonocytic leukemia was diagnosed in a 2-year-old Standardbred mare that had hind limb edema and fever unresponsive to antibiotics. The mare had anemia, thrombocytopenia, and leukocytosis, with circulating myeloblasts and monocytoid cells. A bone marrow specimen was hypercellular, with myeloblasts and monocytoid cells. Peroxidase, chloroacetate esterase, and alpha naphthyl acetate esterase activities were detected in many bone marrow cells. Interstitial pulmonary densities were seen radiographically. The mare was euthanatized and necropsied. Infiltrates of leukemic cells were found m...
Ellenberger C, Schüppel KF, Möhring M, Reischauer A, Alex M, Czerny CP, Fercho A, Schoon HA.Cowpox virus infection associated with a streptococcal septicaemia was diagnosed in a weak German Warmblood filly, born 29 days prematurely, and humanely destroyed on the sixth day of life. At necropsy, ulcerative lesions in the alimentary tract, colitis, polyarthritis and nephritis were observed. Transmission electron microscopical examination of specimens from ulcerative lesions revealed typical orthopox virions. Cowpox virus was unequivocally identified by virological and molecular-biological methods.
Yamanaka T, Tsujimura K, Kondo T, Matsumura T.To investigate the possibilities of two NA inhibitors [oseltamivir carboxylate (OC) and zanamivir (ZA)] as the clinical agents for equine influenza A virus (EIV) infection, we examined the efficacies of these inhibitors against twelve EIVs in vitro. OC and ZA inhibited NA activities of all EIVs with 50% inhibitory concentrations with ranging from 0.017 to 0.130 and from 0.010 to 0.074 microM, respectively. OC and ZA inhibited plaque-forming of all EIVs in MDCK cells with 50% effective concentrations with ranging from 0.015 to 0.097 and from 0.016 to 0.089 microM, respectively, except for one s...
Ohta M, Bannai H, Nemoto M, Kambayashi Y, Tamura N, Tsujimura K.An inactivated equine influenza virus (EIV) vaccine and a live equine herpesvirus type 1 (EHV-1) vaccine are usually administered concurrently to Thoroughbred racehorses in Japan. The objective of this study was to evaluate whether concurrent administration of an inactivated EIV vaccine and a live EHV-1 vaccine in Thoroughbred racehorses influences the antibody response against EIV. We compared the antibody response against EIV in horses administered both vaccines on the same day (Group A; n = 27) and the response in horses administered an inactivated EIV vaccine first and then a live EHV-1 v...
Magdesian KG, Barnum S, Pusterla N. and cause significant morbidity and mortality in foals. Antemortem diagnosis of infection has been complicated by a paucity of tests available for toxin detection. Fecal PCR panels have assays for a variety of toxin gene sequences as well as for several other foal gastrointestinal pathogens. We evaluated results of a comprehensive fecal diarrhea PCR panel in 28 foals that had been presented to a referral hospital because of diarrhea. Sixteen (57%) foals were positive for and/or toxin gene sequences on fecal PCR, including 3 foals positive for NetF toxin. These foals were younger ( = ...
Prutton JSW, Barnum S, Pusterla N.Equine coronavirus (ECoV) is considered an emerging enteric virus with reported morbidity rates ranging from 10 to 83% and fatality rates ranging from 7 to 27% in adult horses; a vaccine for ECoV is currently not available. This study investigated the safety, humoral response and viral shedding in horses inoculated with a commercially available modified-live bovine coronavirus (BCoV) vaccine. Twelve healthy adult horses were vaccinated twice, 3 weeks apart, either orally, intranasally or intrarectally. Two healthy unvaccinated horses served as sentinel controls. Following each vaccine adminis...
Gilliam LL, Ownby CL, McFarlane D, Canida A, Holbrook TC, Payton ME, Krehbiel CR.Rattlesnake bites in horses are not uncommon and the clinical outcomes are widely variable. Treatment of horses with anti-venom is often cost prohibitive and could have negative consequences; therefore, the development of a quantitative test to determine if anti-venom therapy is indicated would be valuable. The objective of this study was to develop an ELISA to detect rattlesnake venom in biological samples from clinically bitten horses. Nineteen horses were enrolled in the study. Urine was available from 19 horses and bite site samples were available from 9 horses. A double sandwich fluoresce...
English AW.The seasonal changes in longevity on herbage of the infective larvae of strongylid nematodes of the horse were studied. During the summer months, 1% of the larvae survived on herbage for 2-3 weeks, with 0.2% still viable for a further 2-3 weeks. Equivalent survival periods in winter were 7-11 weeks and over 11 weeks respectively. During spring and autumn, larvae survived for periods varying from 3-8 weeks. On Rhodes grass (Chloris gayana) growing vigorously in the summer of 1976, the majority of larvae remained in the lowest layers of the pasture, within 10 cm of the soil surface. Very few rea...
Bolin DC, Donahue JM, Vickers ML, Harrison L, Sells S, Giles RC, Hong CB, Poonacha KB, Roberts J, Sebastian MM, Swerczek TW, Tramontin R, Williams NM.During the spring and summer of 2001 and in association with the mare reproductive loss syndrome, 22 terminal and 12 clinical cases of equine pericarditis were diagnosed in central Kentucky. Actinobacillus species were the principal isolates from 8 of 10 nontreated, terminally affected and 3 of 10 clinically affected horses. Enterococcus faecalis and Streptococcus zooepidemicus were cultured from the remaining 2 nontreated terminal cases. No viruses were isolated in tissue culture. Nucleic acid of equine herpesvirus-2 was detected in pericardial and tracheal wash fluids of 3 and 1 individuals,...
Neill SD, O'Brien JJ, McMurray CH, Blanchflower WJ.Cellular fatty acid compositions of contagious equine metritis isolates and three reference Haemophilus equigenitalis cultures were determined by gas chromatography. The chromatographic data were standardised and normalised fatty acid methyl ester (FAME) profiles were produced. The profiles were compared visually and similarity indices were determined using a computer peak matching method. There was little difference between the profiles of the three reference strains, each strain being characterised by three major fatty acids; C 18:1, C 16:0 and 30H-C 14:0. Variations in cultural conditions h...
Minato E, Aoshima K, Kobayashi A, Ohnishi N, Sasaki N, Kimura T.Equine herpesvirus 1 (EHV-1) uses equine major histocompatibility complex class I (MHC class I) as an entry receptor. Exogenous expression of equine MHC class I genes in murine cell lines confers susceptibility to EHV-1 infection. To examine the in vivo role of equine MHC class I as an entry receptor for EHV-1, we generated transgenic (Tg) mice expressing equine MHC class I under the control of the CAG promoter. Equine MHC class I protein was expressed in the liver, spleen, lung, and brain of Tg mice, which was confirmed by Western blot. However, equine MHC class I antigen was only detected in...
Grewar JD, Sergeant ES, Weyer CT, van Helden LS, Parker BJ, Anthony T, Thompson PN.An African horse sickness (AHS) outbreak occurred in South Africa's AHS controlled area in autumn 2016. A freedom from disease survey was performed to establish the likelihood of ongoing circulation of the associated virus during the same period the following year. A single-stage surveillance strategy was employed with a population-level design prevalence of 1% to establish a survey population sensitivity of 95% (probability that one or more positive horses would be detected if AHS was present at a prevalence greater than or equal to the design prevalence). In March 2017, a total of 262 random...
Anderson C, Baha H, Boghdeh N, Barrera M, Alem F, Narayanan A.Zoonotic pathogens that are vector-transmitted have and continue to contribute to several emerging infections globally. In recent years, spillover events of such zoonotic pathogens have increased in frequency as a result of direct contact with livestock, wildlife, and urbanization, forcing animals from their natural habitats. Equines serve as reservoir hosts for vector-transmitted zoonotic viruses that are also capable of infecting humans and causing disease. From a One Health perspective, equine viruses, therefore, pose major concerns for periodic outbreaks globally. Several equine viruses ha...
Eysker M, Boersema JH, Grinwis GC, Kooyman FN, Poot J.The efficacy of a 2% moxidectin equine gel at a dosage rate of 0.4 mg kg-1 was evaluated in a controlled trial at Utrecht University. Twelve yearling castrated male Shetland ponies grazed a pasture of 2 ha from May 1994 until housing in November. Six ponies were treated with moxidectin, whereas the others served as non-treated controls. Necropsy was carried out 35 days after treatment. Greater than 99% efficacy of moxidectin was observed on faecal egg output. No effect of moxidectin was observed on mucosal inhibited early cyathostome L3 (EL3) or on the total numbers of mucosal developing stage...
Sugimoto C, Isayama Y, Kashiwazaki M, Mitani K.The minimal inhibitory concentrations of 31 antimicrobial agents were determined for 99 isolates of Haemophilus equigenitalis by the agar dilution method. All the isolates showed good susceptibility to 26 antimicrobial agents tests, minimal inhibitory concentrations of which were less than 3.13 micrograms/ml for more than 90% of the isolates. Of these agents, 4 macrolides (erythromycin, oleandomycin, kitasamycin, tylosin), 3 tetracyclines (tetracycline, chlortetracycline, oxytetracycline), 1 peptide (colistin), 1 penicillin (ampicillin) and 1 pleuromutilin (tiamulin) were the most active agent...
Kirby AT, Traub-Dargatz JL, Hill AE, Kogan LR, Morley PS, Heird JC.To develop a questionnaire for self-assessment of biosecurity practices at equine boarding facilities and to evaluate infectious disease control practices in these facilities in Colorado. Methods: Cross-sectional study. Methods: 64 equine boarding facilities in Colorado. Methods: Survey questions were rated according to importance for prevention and containment of equine infectious diseases. Point values (range, 0 to 20) were assigned for possible responses, with greater values given for optimal infection control methods. Questionnaires were mailed to equine boarding facilities in Colorado adv...
Tortschanoff M, Aurich C, Rosengarten R, Spergser J.Mycoplasma equigenitalium and Mycoplasma subdolum have been associated with infertility, endometritis, vulvitis and abortions in mares, and with reduced fertility and balanoposthitis in stallions. Despite their role in equine genital disorder, determinants of virulence and pathogenesis as well as factors provoking specific host immune responses have not been identified, so far. To establish the major immunogenic components of Mycoplasma (M.) equigenitalium and M. subdolum, antigen profiles of their type strains as well as 30 clinical isolates were compared by SDS-PAGE and immunoblot analysis u...
Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W.The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, desig...
McGuire TC.Isolated equine immunoglobulin (Ig)G(T) antibodies to equine infectious anemia virus P26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. However, at lower ratios of antibody to antigen precipitation occurred. In addition, complement-fixation by IgG and P26 antigen was inhibited by high concentrations of IgG(T). The unusual reaction pattern noted with IgG(T) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. In situations of nonprecipitability by IgG(T), the adjacent positive control line was inhibited, and th...
Friedman DS, Schoster JV, Pickett JP, Dubielzig RR, Czuprynski C, Knoll JS, Wolfgram LJ.The fungal organism Pseudallescheria boydii was isolated from the cornea of a Quarter Horse with ulcerative keratitis. Despite aggressive hourly medication through a subpalpebral lavage system, with drugs including miconazole and natamycin, the cornea developed a stromal abscess. Orbital exenteration was performed after 3 weeks. The fungal isolate was later determined to be resistant to all 8 antifungal drugs tested. Microscopic examination of the cornea revealed fungal hyphae throughout the corneal stroma and penetrating the Descemet membrane. Pseudallescheria boydii has not been implicated p...
Frazer JL, Perkins NR, Pitt D.During the 2007 equine influenza (EI) outbreak, infected horses were quarantined at Morgan Park Recreational Grounds (MPRG) near Warwick, Queensland. Some individuals caring for horses were reported to have made return journeys between MPRG and home properties containing other horses during the time there was active infection at MPRG. Objective: A retrospective cohort study to assess the biosecurity and hygiene measures undertaken and their outcomes. Methods: All individuals recorded as being responsible for caring for one or more horses at MPRG, and who were also recorded on entry and exit lo...
DiPietro JA, Todd KS, Lock TF, Reuter-Dallman V.Fifty horses from a herd known to have benzimidazole-resistant small strongyles were treated with febantel (6 mg/kg), combinations of febantel (6 mg/kg) and piperazine citrate (25 or 55 mg base/kg), thiabendazole (44 mg/kg), or placebo (0.6 ml of water/kg). Pretreatment and 7-day posttreatment fecal examinations were done. Fecal cultures, strongyle egg per gram (epg) counts, sugar flotation fecal examinations, and in vitro testing for benzimidazole resistance were performed. Results of fecal examinations before treatment were similar in all horses, and results of testing were positive for benz...
Štritof Z, Mitchell C, Turk N, Habuš J, Hađina S, Perharić M, Waller AS.Clinical cases resembling strangles are regularly seen in some areas of Croatia. However, there are no data on the prevalence of infection and the clinical forms or geographic distribution of the disease. The aim of this study was to determine the seroprevalence of Streptococcus equi subspecies equi in horses resident in Croatia, in order to estimate the geographic distribution of infection. The study included 291 horse sera from the eight counties where the majority of Croatian horses are kept. Sera were tested by indirect ELISA (iELISA) for the presence of serum antibodies against S. equi pr...
Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Stamper S, Granstrom DE.Studies in a band of ponies harboring Population S benzimidazole-resistant small strongyles were initiated in 1974 and have continued for 18 years. Treatment (bimonthly) was with cambendazole for the first 4 years and with oxibendazole (OBZ) for the next 14 years. Data on the first 10 years have been published. The present investigation includes the last 8 years (4 October 1984-11 September 1992), which are the seventh through fourteenth years, of treatment with OBZ. Pre- and posttreatment mean counts of strongyle eggs (epg) and larvae (lpg) per gram of feces were determined biweekly during th...
Mitchell SM, Zajac AM, Davis WL, Lindsay DS.Toxoplasma gondii is an important apicomplexan parasite of humans and other warm-blooded animals. Ponazuril is a triazine anticoccidial recently approved for use in horses in the United States. We investigated the mode of action of ponazuril against developing RH strain T. gondii tachyzoites in African green monkey kidney cells. Host cells were infected with 2.0 x 10(5) tachyzoites and treated with 5 microg/ml ponazuril. Cultures were fixed and examined by transmission electron microscopy 3 days after treatment. Ponazuril interfered with normal parasite division. This led to the presence of mu...
Liu IK, Pascoe DR, Chang LW, Zee YC.Serum antibody concentrations against influenza A-equi-1 virus and A-equi-2 virus were measured in a group of 18 foals from birth to 4 months of age. More than 50% of the foals were seronegative to A-equi-1 virus infection by 4 weeks of age, with titers of less than or equal to 1:16. For A-equi-2 virus, more than 50% of the foals were seronegative by 2 weeks of age, with titers of less than or equal to 1:8. Passively derived antibodies against influenza A-equi-1 virus and A-equi-2 virus in foals obtained from recently vaccinated mares and from mares not vaccinated within 6 months before foalin...
Smith R, Chaffin MK, Cohen ND, Martens RJ.To characterize changes in lymphocyte subsets over time in foals from birth to 18 weeks of age, accounting for differences among individuals, and to determine the effect of overnight storage of blood samples on foal lymphocyte subset concentrations. Methods: 8 healthy Quarter Horse foals from birth to 18 weeks of age. Methods: Blood samples were collected longitudinally from birth to 18 weeks of age and a CBC performed on each sample. The samples were stained for lymphocyte markers, either immediately or after overnight storage and analyzed by flow cytometry. Results: Total leukocytes, total l...
Arora S, Sharma S, Goel SK, Singh US.Implementation of the recommended post-exposure prophylaxis by vaccination and specific immunoglobulin therapy for rabies is largely hampered by its high cost and inadequate production. Therefore, the development and availability of an economic preparation of rabies immunoglobulin is a high priority for India, where rabies is a major cause of death. We studied the efficacy of four different adjuvants in raising antibodies to rabies antigen in older, discarded equines. Methods: Eleven equines, 23-26 years old, were divided into 4 groups to receive four different adjuvants in small amounts (1-2 ...
Traub-Dargatz J, Kopral C, Wagner B.This study is the first report estimating, on a national basis, the use of various biosecurity practices, singly and in combination, on U.S. equine operations. Use of biosecurity practices is described for operations by risk level, based on reported exposure of resident horses to outside horses during the previous 12 months. In addition, the association between use of various biosecurity practices and use of antibiotics to treat infectious disease in both adult equids and foals is reported. The comparison of these study findings with previously reported data in the literature is limited by the...
Lane JG, Gibbs C, Meynink SE, Steele FC.The radiographic procedures used for examination of the facial area and paranasal sinuses of 235 horses are reported. Clinical indications for these examinations and the diagnoses made are reviewed. Unilateral nasal discharge was the commonest reason for radiography, accounting for about one third of cases, most of which had radiological signs of paranasal sinus disease recognisable on erect lateral films. Oblique projections were required to obtain further information about the maxillary dental arcades and ventro-dorsal views demonstrated sinus expansion and extension of disease into the nasa...
Wassall DA, Gregory RJ, Phipps LP.The detection of antibodies against Trypanosoma equiperdum in 689 equid sera was compared by enzyme-linked immunosorbent assay (ELISA), the complement fixation test (CFT) and an indirect immunofluorescent test (IIF). CFT was the least sensitive technique, susceptible to anti-complementary factors and the most technically demanding. IIF was more sensitive, but was only suitable for testing limited numbers of samples. In this study, ELISA was the most sensitive test, the least labour intensive and lends itself to a considerable degree of automation. It is suggested that ELISA would be relatively...
