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Topic:Infection
Infections in horses encompass a range of diseases caused by various pathogens, including bacteria, viruses, fungi, and parasites. These infections can affect different systems within the horse, such as the respiratory, gastrointestinal, and integumentary systems, leading to a variety of clinical signs depending on the pathogen and the severity of the infection. Common infectious diseases in horses include equine influenza, strangles, and equine herpesvirus. Diagnosis often involves clinical examination, laboratory testing, and sometimes imaging, to identify the causative agent and assess the extent of the disease. Treatment strategies may include antimicrobial therapy, supportive care, and preventive measures such as vaccination and biosecurity practices. This page aggregates peer-reviewed research studies and scholarly articles that explore the pathogenesis, diagnosis, treatment, and prevention of infectious diseases in equine populations.
[The prevention of pneumovagina and the effect of the Caslick operation on fertility: a retrospective study]. Mares with a large vulvar orifice have an increased risk of pneumovagina, which is associated with reduced fertility. Treatment is by means of the Caslick operation, by which size of the vulvar orifice is reduced. Factors that influence the occurrence of pneumovagina are the age and fertility status of the mare. In this study the risk factors for pneumovagina and the effect of the Caslick operation on fertility were investigated. In 1994, 1995, and 1996 a total of 967 mares were sent for service at a stud. Of these mares, 116 underwent a Caslick operation. The operated mares were older than th...
Presumed clostridial and aerobic bacterial infections of the cornea in two horses. Microscopic examination of Gram-stained tissue specimens collected from severe corneal ulcers in 2 horses revealed large gram-positive rods suggestive of Clostridium spp. Clostridium perfringens was isolated from specimens collected from horse 1; anaerobic organisms were not detected in specimens from horse 2. Aerobic bacterial culture revealed Aeromonas hydrophila and Enterobacter cloacae in specimens collected from horses 1 and 2, respectively. An insect exoskeleton was presumed to be the underlying cause of ulceration in horse 1. Cause of ulceration in horse 2 was not determined. Antibiotic...
Risk factors for nosocomial Salmonella infection among hospitalized horses. To identify risk factors for nosocomial Salmonella infections among hospitalized horses. Methods: Longitudinal study. Methods: 1,583 horses hospitalized in an intensive care unit between January 1992 and June 1996. Methods: Survivor functions were used to estimate time to shedding salmonellae for various Salmonella serotypes. Survival analysis was then used to determine how variables associated with patient management, environmental conditions, hospital conditions, and other disease processes affected the risk of nosocomial Salmonella infection. Results: 78 horses shed Salmonella organisms: 35...
Molecular characterization of equine isolates of Streptococcus pneumoniae: natural disruption of genes encoding the virulence factors pneumolysin and autolysin. Although often considered a strict human pathogen, Streptococcus pneumoniae has been reported to infect and cause pneumonia in horses, although the pathology appears restricted compared to that of human infections. Here we report on the molecular characterization of a group of S. pneumoniae isolates obtained from horses in England and Ireland. Despite being obtained from geographically distinct locations, the isolates were found to represent a tight clonal group, virtually identical to each other but genetically distinguishable from more than 120 divergent isolates of human S. pneumoniae. A co...
Characterisation of equine T helper cells: demonstration of Th1- and Th2-like cells in long-term equine T-cell cultures. The aim of this study was to characterise CD4+T-cells in equines, as these cells are pivotal in establishing immune responses or regulating established ones. Peripheral blood mononuclear cells from a pony immunised with ovalbumin were cultured in vitro in the presence of the specific antigen and autologous antigen presenting cells. During the antigen starvation phase, cells were maintained on recombinant equine IL-2. After 35 days of culture, most of the cells were CD4+, CD8-and sIg-. Cells proliferated specifically in the presence of antigen, as tested on day 42 of culture. These cells were a...
Antigenic profile of African horse sickness virus serotype 4 VP5 and identification of a neutralizing epitope shared with bluetongue virus and epizootic hemorrhagic disease virus. African horse sickness virus (AHSV) causes a fatal disease in horses. The virus capsid is composed of a double protein layer, the outermost of which is formed by two proteins: VP2 and VP5. VP2 is known to determine the serotype of the virus and to contain the neutralizing epitopes. The biological function of VP5, the other component of the capsid, is unknown. In this report, AHSV VP5, expressed in insect cells alone or together with VP2, was able to induce AHSV-specific neutralizing antibodies. Moreover, two VP5-specific monoclonal antibodies (MAbs) that were able to neutralize the virus in a ...
Equine nasal and paranasal sinus tumours. Part 1: review of the literature and tumour classification. The normal gross and histological anatomy of the equine nasal and paranasal sinuses are reviewed and the relationships between the local anatomy, the occurrence of different tumour types, and of tumour spread are examined. The histological classification of the more common equine sinonasal tumours and tumour-like lesions are discussed. Clinical and pathological descriptions of 50 more recently recorded such tumours are separately tabulated. The literature shows that equine sinonasal tumours, both endemic and sporadic, are relatively uncommon in horses, with non-neoplastic growths such as maxil...
Serologic testing of horses for granulocytic ehrlichiosis, using indirect fluorescent antibody staining and immunoblot analysis. To diagnose granulocytic ehrlichiosis in horses, compare results of indirect fluorescent antibody (IFA) staining procedures with those of immunoblot analysis, and compare serologic test findings with polymerase chain reaction (PCR) results. Methods: 69 horses with high rectal temperatures (> or = 39 C) and lethargy, anorexia, or limb edema. Methods: 43 convalescent serum samples obtained from 38 horses 2 to 18 weeks after onset of illness were analyzed by use of immunoblot procedures and IFA staining methods, using the NCH-1 or BDS ehrlichial strains. Blood samples from 69 acutely ill horse...
Strategic control of gastrointestinal nematode and lungworm infections with eprinomectin at turnout and eight weeks later. Two groups of 10 first-year grazing cattle were either left untreated as controls (group 1) or treated with eprinomectin as a pour-on application at turnout and eight weeks later (group 2). The control group developed a mild infection with gastrointestinal nematodes and lungworms during the season, whereas the treated animals remained healthy. The interval between the treatments allowed the establishment of adult worms, but the egg counts remained negligible. The total number of eggs shed by the treated cattle during the grazing season was significantly smaller than by the controls.
Tapeworms as a cause of intestinal disease in horses. Until recently, the equine tapeworm Anoplocephala perfoliata was difficult to diagnose and considered to be of questionable pathogenicity. Here, Chris Proudman and Sandy Trees describe recent advances in the immunodiagnosis of this parasite that have facilitated epidemiological studies. These studies suggest that A. perfoliata may be an important cause of intestinal disease in the horse and demonstrate a dose-response relationship between infection intensity and risk of disease. If tapeworm infection is a risk factor for ileocaecal colic, the identification and treatment of infected individual...
Thoracic and abdominal blastomycosis in a horse. A 5-year-old Quarter Horse mare was examined because of lethargy, fever, and weight loss of 1 month's duration. Thoracic auscultation revealed decreased lung sounds cranioventrally. Thoracic ultrasonography revealed bilateral anechoic areas with hyperechoic strands, consistent with pleural effusion and fibrin tags. A large amount of free fluid was evident during abdominal ultrasonography. Abnormalities included anemia, hyperproteinemia, hyperglobulinemia, hyperfibrinogenemia, and hypoalbuminemia. Thoracic radiography revealed alveolar infiltrates in the cranial and caudoventral lung fields. A ...
Cytological and bacteriological findings in guttural pouch lavages of clinically normal horses. Percutaneous washes of the guttural pouches were obtained from two groups of 15 clinically normal horses, one lightly exercised and the other heavily exercised. Microbiological and cytological studies showed a wide variation in the differential cell counts. The cytological pattern of the normal lavages (< 5 per cent neutrophils) was characterised by a large proportion of ciliated columnar epithelial cells, a few non-ciliated cuboidal epithelial cells, and less than 1 per cent monocytes, lymphocytes, and eosinophils. Abnormal lavages (with more than 5 per cent neutrophils) had higher levels ...
Borna disease virus infection in racing horses with behavioral and movement disorders. Borna disease virus (BDV) is a neurotropic agent with capacity to infect and cause neurological disease in a broad range of warmblooded hosts including horses, sheep, cattle, cats, and possibly also humans. The epidemiology of BDV is largely unknown. However, it is likely that subclinically infected animals may represent potential virus reservoirs. In two groups of Swedish racing horses, one clinically healthy and one consisting of horses with diffuse neurological signs, the BDV seroprevalence was 24.5% and 57.7%, respectively. BDV RNA was detected in peripheral blood mononuclear cells in 8 ou...
Ultrasound as an aid for diagnosis of ovarian abscesses in two mares. This report describes two mares presented for evaluation of anorexia, fever of unknown origin, and weight loss. Clinical examination, laboratory findings, and transrectal ultrasonographic images suggested ovarian abscessation. One mare was successfully treated medically. Because of financial considerations, the second mare was euthanatized and a postmortem examination was performed. At necropsy, there was an enlarged right ovary with an adhesion to the large colon. Microscopic findings were characteristic of an ovarian abscess.
The seroprevalence of equine trypanosomosis in the pantanal. Since little information is available on the epizootiological status of Trypanosoma evansi in South America and particularly Brazil, we evaluated equine serum samples collected in 1993, 1994, 1995 and 1997 for the presence of antibodies against this trypanosome species. Our study shows corroborative evidence about the correlation among high T. evansi seroprevalence and the rainy season in the Pantanal, Brazil. The higher seroprevalence was 79.2% in horses from a ranch located in the Nhecolândia sub-region in 1994 and the lower 5.8% in animals from the same ranch in 1997. No seroprevalence was...
Are Sarcocystis neurona and Sarcocystis falcatula synonymous? A horse infection challenge. Equine protozoal myeloencephalitis (EPM) is a debilitating neurologic disease of the horse. The causative agent. Sarcocystis neurona, has been suggested to be synonymous with Sarcocystis falcatula, implying a role for birds as intermediate hosts. To test this hypothesis, opossums (Didelphis virginiana) were fed muscles containing S. falcatula sarcocysts from naturally infected brown-headed cowbirds (Molothrus ater). Ten horses were tested extensively to ensure no previous exposure to S. neurona and were quarantined for 14 days, and then 5 of the horses were each administered 10(6) S. falcatula...
Investigations on the ability of clenbuterol hydrochloride to reduce clinical signs and inflammation associated with equine influenza A infection. Twenty-four Quarter Horse and Quarter Horse-cross yearlings were experimentally infected with influenza A virus (Influenza A/equine/Saskatoon/90 [H3N8]) by nebulisation. In a double blind controlled trial the horses were randomly assigned to 3 groups of 8 animals. Group 1 received a placebo, (carrier syrup), Group 2 the labelled dose and Group 3 twice the labelled dose of clenbuterol hydrochloride. All treatments were given per os b.i.d. for 10 days and started on the day of infection. The horses were monitored for clinical signs of influenza infection for 14 days. Bronchoalveolar lavages were...
Repeated administration of trimethoprim/sulfadiazine in the horse–pharmacokinetics, plasma protein binding and influence on the intestinal microflora. Six healthy adult horses were given repeated administrations of trimethoprim/ sulfadiazine (TMP/SDZ) intravenously (i.v.) (2.5 mg/kg TMP and 12.5 mg/kg SDZ) and orally (p.o.) as a paste (5 mg/kg TMP and 25 mg/kg SDZ). Both formulations were given twice daily for 5 days, with a 3-week interval between i.v. and oral administration. The influence of the drug combination on the intestinal microflora was examined and the plasma concentrations, pharmacokinetic parameters and plasma protein binding were determined. There were no major changes in the bacterial intestinal flora and no clinical evidence...
Role of interferon and interferon regulatory factors in early protection against Venezuelan equine encephalitis virus infection. To investigate the role of type I interferon (IFN) and its regulatory transacting proteins, interferon regulatory factors (IRF-1 and IRF-2), in early protection against infection with virulent Venezuelan equine encephalitis virus (VEE), we utilized mice with targeted mutations in the IFN-alpha/beta receptor, IRF-1, or IRF-2 genes. IFN-alpha/beta-receptor knockout mice are highly susceptible to peripheral infection with virulent or attenuated VEE, resulting in their death within 24 and 48 h, respectively. Treatment of normal macrophages with anti-IFN-alpha/beta antibody prior to and during infe...
Methicillin-resistant Staphylococcus aureus outbreak in a veterinary teaching hospital: potential human-to-animal transmission. During a 13-month period, 11 equine patients visiting a veterinary teaching hospital for various diagnostic and surgical procedures developed postprocedural infections from which methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA) strains were isolated. The S. aureus isolates were identified by conventional methods that included Gram staining, tests for colonial morphology, tests for clumping factor, and tests for coagulase and urease activities and were also tested with the API STAPH IDENT system. Antimicrobial susceptibility tests were performed by the disk diffusion method. The b...
Evaluation of peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity for detection of septic peritonitis in horses. To determine whether peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity can be used to differentiate horses with septic peritonitis from those with nonseptic peritonitis. Methods: Prospective study. Methods: 46 horses, including 10 healthy horses, 15 horses with septic peritonitis, and 21 horses with nonseptic peritonitis. Methods: Peritoneal fluid and blood samples were analyzed for pH, glucose concentration, and lactate dehydrogenase activity. Complete blood cell counts were performed, and peritoneal fluid samples were submitted for bacterial culture. Results: Hor...
Gag protein epitopes recognized by CD4(+) T-helper lymphocytes from equine infectious anemia virus-infected carrier horses. Antigen-specific T-helper (Th) lymphocytes are critical for the development of antiviral humoral responses and the expansion of cytotoxic T lymphocytes (CTL). Identification of relevant Th lymphocyte epitopes remains an important step in the development of an efficacious subunit peptide vaccine against equine infectious anemia virus (EIAV), a naturally occurring lentivirus of horses. This study describes Th lymphocyte reactivity in EIAV carrier horses to two proteins, p26 and p15, encoded by the relatively conserved EIAV gag gene. Using partially overlapping peptides, multideterminant and poss...
Streptococcus equi but not Streptococcus zooepidemicus produces potent mitogenic responses from equine peripheral blood mononuclear cells. Streptococcus equi causes equine strangles. The acute disease has many of the hallmarks of an acute response including high fever, elevated plasma fibrinogen and neutrophilia, affects known to be mediated by proinflammatory cytokines. The objective of this study was to screen-culture supernatants from equine clinical isolates of S. equi and S. zooepidemicus for stimulation of mitogenic responses by horse peripheral blood mononuclear cells. Mitogenicity comparable to that of concanavalin A was detected in culture supernatants of S. equi strains but not in those of S. zooepidemicus. Mitogenicity...
The gamma2 late glycoprotein K promoter of equine herpesvirus 1 is differentially regulated by the IE and EICP0 proteins. The equine herpesvirus 1 immediate-early (IE) phosphoprotein is essential for the activation of transcription from viral early and late promoters and trans-represses its own promoter. Transient-transfection assays showed that the IE protein trans-represses the gamma2 late gK promoter. Gel shift and DNase I footprinting assays demonstrated that the IE protein binds to the gK promoter sequences from -42 to -26 and from -13 to +12 that overlap the transcription initiation site (+1). These results indicated that the IE protein binds to the transcription initiation site of the gK promoter sequences...
A sensitive polymerase chain reaction based assay for the detection of Setaria digitata: the causative organism of cerebrospinal nematodiasis in goats, sheep and horses. A sensitive PCR assay for the detection of Setaria digitata has been developed. Two oligonucleotide primers (17 nt) were designed from a previously cloned and characterized tandemly arranged repetitive sequence of Setaria digitata. Using these primers, it was possible to amplify small quantities (100 fg) of S. digitata genomic DNA. A simple procedure, using proteinase K and non-ionic detergent NP 40, was followed to process the host blood samples and mosquitoes harbouring L3 larvae. The sensitivity of the polymerase chain reaction based assay surpasses the microscopic detection and the previou...
Influence of age and plasma treatment on neutrophil phagocytosis and CD18 expression in foals. The aim of this study was to evaluate the influence of age and plasma treatment on neutrophil phagocytosis, CD18 expression and serum opsonic capacity in foals in field settings. Microbial infections constitute a large threat in young foals and neutrophil functions are crucial for the defense. Blood samples were obtained from 13 foals at seven time points between the ages of 2 and 56 days and once from 16 adult horses. Six of the foals were treated with adult plasma at the age of 1 week. Neutrophil phagocytosis of yeast after various opsonizations and the expression of complement adhesion rece...
Evaluation of temporal and spatial clustering of horses with Corynebacterium pseudotuberculosis infection. To determine whether horses with Corynebacterium pseudotuberculosis infections that were examined at a veterinary medical teaching hospital between July 1, 1992, and June 30, 1994 had patterns of temporal or spatial clustering. Methods: 134 case and 800 control horses randomly selected from all non-case horses admitted during the study period. Methods: Admission date and geographic location were determined. Scan, Cuzick & Edwards', and Knox tests were applied to determine whether case horses had patterns of temporal or spatial clustering. Results: For all windows > or = 3 days (134 case...
Purification and biochemical characterization of equine pulmonary surfactant protein D. To characterize surfactant protein D (SP-D) isolated from bronchoalveolar lavage fluid (BALF) of healthy horses. Methods: BALF from 10 Thoroughbreds (5 males, 5 females; 26 to 40 months old) without history or clinical signs of respiratory tract disease. Methods: BALF was obtained and centrifuged at 33,000 X g. The supernatant was applied to a mannose-Sepharose 6B affinity column in the presence of calcium, and the bound protein fraction was analyzed by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis; amino acid composition was determined and partial seque...
Amylopectinosis in fetal and neonatal Quarter Horses. Three Quarter Horses, a stillborn filly (horse No. 1), a female fetus aborted at approximately 6 months of gestation (horse No. 2), and a 1-month-old colt that had been weak at birth (horse No. 3), had myopathy characterized histologically by large spherical or ovoid inclusions in skeletal and cardiac myofibers. Smaller inclusions were also found in brain and spinal cord and in some cells of all other tissues examined. These inclusions were basophilic, red-purple after staining with periodic acid-Schiff (both before and after digestion with diastase), and moderately dark blue after staining wi...
