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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.
Immune response to vaccines based upon the VapA protein of the horse pathogen, Rhodococcus equi, in a murine model. Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results sh...
Experimental infection of ponies with Sarcocystis fayeri and differentiation from Sarcocystis neurona infections in horses. Sarcocystis neurona and Sarcocystis fayeri infections are common in horses in the Americas. Their antemortem diagnosis is important because the former causes a neurological disorder in horses, whereas the latter is considered nonpathogenic. There is a concern that equine antibodies to S. fayeri might react with S. neurona antigens in diagnostic tests. In this study, 4 ponies without demonstrable serum antibodies to S. neurona by Western immunoblot were used. Three ponies were fed 1 x 10(5) to 1 x 10(7) sporocysts of S. fayeri obtained from dogs that were fed naturally infected horse muscles. A...
Measurement of serum IgG in foals by radial immunodiffusion and automated turbidimetric immunoassay. Hypogammaglobulinemia as a result of failure of transfer of passive immunity (FTPI) is an important risk factor for infectious disease in neonatal foals. The current gold standard for determining serum immunoglobulin concentrations is radial immunodiffusion (RID). The purpose of this study was to compare immunoglobulin concentrations measured by RID with those determined by an automated turbidimetric immunoassay (TIA), which has a much shorter turnaround time. Immunoglobulin concentrations were measured by both RID and TIA in serum collected from 84 neonatal foals. Sixty-seven foals had result...
Encrusted cystitis secondary to Corynebacterium matruchotii infection in a horse. A 17-year-old gelding was evaluated because of dysuria, inappetence, and weight loss. Cystoscopy revealed severe mucosal ecchymoses with luminal hemorrhage and accumulations of crystalloid sludge. Analysis of a urine sample revealed isosthenuria, an alkaline pH, pyuria, hematuria, bacteriuria, and numerous calcium carbonate crystals. Histologic examination of bladder mucosa biopsy specimens revealed severe neutrophilic infiltration with mineralization. A diagnosis of encrusted cystitis exacerbated by sabulous urolithiasis was made. A Corynebacterium sp susceptible to penicillin, sulfonamide, a...
Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine e...
The EICP27 protein of equine herpesvirus 1 is recruited to viral promoters by its interaction with the immediate-early protein. The equine herpesvirus 1 (EHV-1) EICP27 protein cooperates with either the immediate-early (IE) or the EICP0 protein to synergistically trans-activate viral promoters. GST-pulldown and co-immunoprecipitation assays revealed that the EICP27 protein's cooperation with the IE or the EICP0 protein involves its physical interaction with these viral proteins. In the case of the IE-EICP27 protein interaction, IE residues 424 to 826 and EICP27 residues 41 to 206 harbor the interactive domains. Electrophoretic mobility shift assays (EMSA) suggested that the EICP27 protein is not a sequence-specific DNA...
Suspected venous air embolism in a horse. A horse which had had a caecal impaction for 10 days was treated by means of an ileocolostomy [corrected] but failed to respond satisfactorily. Before a second laparotomy was performed it was observed to have dislodged the extension set from a jugular catheter and air was heard being sucked into the vein. It became very agitated but was anaesthetised again and the impaction was removed through an incision in the apex of the colon [corrected] After recovering from the anaesthesia it developed severe signs of pruritus which subsided only after 12 hours. These signs were considered most likely to...
Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. Methods: Prospective case-control study. Methods: 5230 foals on 138 breeding farms with 9136 horses. Methods: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. Results: A number of variables relating to farm size and desirable management practices were significantly associated with increased...
Detection of antibodies to Borrelia burgdorferi in naturally infected horses in the USA by enzyme-linked immunosorbent assay using whole-cell and recombinant antigens. Blood samples were collected from 98 horses suspected of having borreliosis or granulocytic ehrlichiosis in Connecticut and New York State, USA during 1985, 1995, and 1996. Serum antibodies to Borrelia burgdorferi were detected by an enzyme-linked immunosorbent assay (ELISA), based on whole-cell and recombinant antigens, in 82 (84%) horses. Of the 181 sera tested, 59% were positive, using whole-cell antigens, compared to 48% with protein (p)37 and 35% with VlsE antigens. An ELISA containing either of these fusion proteins can be used as an adjunct to general screening by an ELISA or immunoblot...
Molecular characterizations of human and animal group a rotaviruses in the Netherlands. To gain more insight into interspecies transmission of rotavirus group A, human and animal fecal samples were collected between 1997 and 2001 in The Netherlands. A total of 110 human stool samples were successfully P and G genotyped by reverse transcriptase PCR. All strains belonged to the main human rotavirus genotypes G1 to G4, G9, [P4], [P6], [P8], and [P9]. [P8]G1 was predominant, and 5.5% belonged to the G9 genotype. Eleven percent of all P[8] genotypes could be genotyped only by a recently published modified primer. Rotavirus-positive fecal samples from 28 calf herds were genotyped by DN...
Persistence of anti-zonae pellucidae antibodies following a single inoculation of porcine zonae pellucidae in the domestic equine. In this study of equids, we investigated the antibody response and the effect on the estrous cycle following a single inoculation of porcine zonae pellucidae (pZP) employing controlled-release methodology. We also investigated the use of two different water-soluble adjuvants as an alternative to oil-based adjuvants. Twenty-seven domestic mares were inoculated with various formulations of pZP and adjuvant. We showed that the anti-pZP antibodies generated as a result of the inoculations persisted for at least 43 weeks (length of the study). Of the various formulations used in the study, pZP and ...
Management of complicated wounds. Most injuries, including those with significant tissue loss, can be successfully managed with proper therapy. With delayed healing, potential causes for the delay, such as sequestra, foreign bodies, and excessive motion,should be determined and treated to permit complete wound resolution. Horses have the innate ability to heal rapidly; however, minor injuries can quickly turn into complicated wounds, given the severity of the inciting trauma and the less than ideal environment in which the horses are housed. Wound management must focus on a combination of timely surgical and medical interventi...
Disposition of orally administered cefpodoxime proxetil in foals and adult horses and minimum inhibitory concentration of the drug against common bacterial pathogens of horses. To determine the disposition of orally administered cefpodoxime proxetil in foals and adult horses and measure the minimum inhibitory concentrations (MICs) of the drug against common bacterial pathogens of horses. Methods: 6 healthy adult horses and 6 healthy foals at 7 to 14 days of age and again at 3 to 4 months of age. Methods: A single dose of cefpodoxime proxetil oral suspension was administered (10 mg/kg) to each horse by use of a nasogastric tube. In 7- to 14-day-old foals, 5 additional doses were administered intragastrically at 12-hour intervals. The MIC of cefpodoxime for each of 173...
Microbiologic and pathologic findings in an epidemic of equine pericarditis. 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,...
Use of a Bayesian risk-mapping technique to estimate spatial risks for mare reproductive loss syndrome in Kentucky. To estimate spatial risks associated with mare reproductive loss syndrome (MRLS) during 2001 among horses in a specific study population and partition the herd effects into those attributable to herd location and those that were spatially random and likely attributable to herd management. Animals-Pregnant broodmares from 62 farms in 7 counties in central Kentucky. Methods: Veterinarians provided the 2001 abortion incidence proportions for each farm included in the study. Farms were georeferenced and data were analyzed by use of a fully Bayesian risk-mapping technique. Results: Large farm-to-fa...
Molecular detection of Leptospira kirschneri in tissues of a prematurely born foal. Leptospirosis was identified to be the possible cause of premature birth in a foal on a farm with a history of repeated abortions. Using an appropriate polymerase chain reaction (PCR) assay, the presence of Leptospira kirschneri was detected in the tissues of the prematurely born foal. Further confirmation of L. kirschneri was obtained by nucleotide sequence analysis of the PCR-amplified DNA fragment and the partial 16S ribosomal RNA gene sequence. This report further supports mounting evidence that a PCR assay capable of detecting L. kirschneri should be included in routine diagnostic investi...
Identification of strongyle eggs from anthelmintic-treated horses using a PCR-ELISA based on intergenic DNA sequences. The efficacy of five daily fenbendazole (FBZ) treatments was tested against benzimidazole-resistant cyathostomins in naturally infected horses (n=13). Horses were treated with pyrantel embonate (PYR) to remove adult strongyles followed, 7 days later, by a 5-day course of FBZ. The PYR treatment produced an average faecal egg count reduction of 98%. All samples were negative by faecal egg count 7 days after the start of the FBZ treatment. Positive egg counts were observed from 28 days after the start of FBZ treatment and all horses displayed positive faecal egg counts by 77 days after treatment....
Prostaglandins and reproduction in female farm animals. Prostaglandins impact on ovarian, uterine, placental, and pituitary function to regulate reproduction in female livestock. They play important roles in ovulation, luteal function, maternal recognition of pregnancy, implantation, maintenance of gestation, microbial-induced abortion, parturition, postpartum uterine and ovarian infections, and resumption of postpartum ovarian cyclicity. Prostaglandins have both positive and negative effects on reproduction; they are used to synchronize oestrus, terminate pseudopregnancy in mares, induce parturition, and treat retained placenta, luteinized cysts, ...
Venezuelan equine encephalitis virus, southern Mexico. Equine epizootics of Venezuelan equine encephalitis (VEE) occurred in the southern Mexican states of Chiapas in 1993 and Oaxaca in 1996. To assess the impact of continuing circulation of VEE virus (VEEV) on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in Chiapas State. Human serosurveys and risk analyses indicated that long-term endemic transmission of VEEV occurred among villages with seroprevalence levels of 18% to 75% and that medical personnel had a high risk for VEEV exposure. Seroprevalence in wild animals suggested cotton rats as pos...
Differential effects of virulent and avirulent equine infectious anemia virus on macrophage cytokine expression. Equine infectious anemia virus (EIAV) causes rapid development of acute disease followed by recurring episodes of fever, thrombocytopenia, and viremia. Most infected equid eventually bring the virus under immunological control. We recently reported the development of an equine-specific ribonuclease protection assay (RPA) to quantitate mRNA levels of 10 cytokines. Using this newly developed RPA, we now show significant differences in cytokine induction in equine monocyte-derived macrophages (EMDM) exposed to virulent and avirulent EIAV. Virulent EIAV17 induced significant increases in interleuk...
Keratomycosis in six horses in the United Kingdom. Six horses with keratomycosis were examined and three different clinical expressions of the disease were recognised. The diagnostic work-up and response to treatment is described.
Comparison of HIV-1 and EIAV-based lentiviral vectors in corneal transduction. In this study we compare the ability of self-inactivating Human Immunodeficiency Virus 1 (HIV-1) and Equine Infectious Anaemia Virus (EIAV)-based vectors to mediate gene transfer to rabbit and human corneas and to a murine corneal endothelial cell line. Both vectors were pseudotyped with vesicular stomatitis virus-G (VSV-G) envelope and contained marker transgenes under the control of an internal CMV promoter. For specificity of action, the heterologous promoter in the EIAV-vector was exchanged for an inducible E-Selectin promoter, previously shown to regulate gene-expression in a plasmid syst...
West Nile virus in the vertebrate world. West Nile virus (WNV), an arthropod-borne virus belonging to the family Flaviviridae, had been recognized in Africa, Asia and the south of Europe for many decades. Only recently, it has been associated with an increasing number of outbreaks of encephalitis in humans and equines as well as an increasing number of infections in vertebrates of a wide variety of species. In this article, the data available on the incidence of WNV in vertebrates are reviewed. Moreover, the role of vertebrates in the transmission of WNV, the control of WNV infections in veterinary medicine as well as future perspect...
Arterial lactate concentration, hospital survival, sepsis and SIRS in critically ill neonatal foals. Blood lactate concentration has been shown to be a useful clinical indicator in human patients, but has not been formally investigated in critically ill foals. Objective: To investigate the association of blood lactate with hospital survival, markers of cardiovascular status, metabolic acid base status, sepsis and systemic inflammatory response syndrome (SIRS). Methods: A database containing clinical, haematological, plasma biochemical and hospital outcome data on neonatal foals referred to an intensive care unit in 2000-2001 was analysed. Seventy-two foals for which arterial lactate was measu...
Immunoglobulin and peripheral B-lymphocyte concentrations in Fell pony foal syndrome. Fell pony foals are affected by a congenital fatal disease that leads to profound anaemia and immunodeficiency. Previous studies comparing healthy and affected foals have shown normal T-cell populations, but a severe B-lymphopenia. Objective: To measure the levels of individual immunoglobulin subisotypes in normal and affected Fell ponies and correlate these levels with the number of peripheral B-lymphocytes. Methods: Serum levels of individual immunoglobulin subisotypes were measured by ELISA and correlated with the number of peripheral B-lymphocytes (measured by flow cytometry). Results: Aff...
Histology and ultrastructure of the equine lingual tonsil. I. Crypt epithelium and associated structures. The microstructural and ultrastructural features of the equine lingual tonsil were studied in five young horses. Located at the root of the tongue it presented an irregular surface with rounded elevations, numerous folds and crypts. Stratified squamous non-keratinized epithelium lining its outer surface was modified by heavy infiltration of lymphoid cells to form reticular epithelium within the crypt. The latter implies a role in initiating and maintaining immune responses to incoming infectious agents and antigens. Lamellated structures resembling Hassall's corpuscle were observed towards the...
Semi-nested PCR for the specific detection of Habronema microstoma or Habronema muscae DNA in horse faeces. Habronema microstoma and Habronema muscae (Spirurida: Habronematidae) are parasitic nematodes which infect the stomach and/or skin of equids. The accurate diagnosis of gastric habronemosis is central to studying its epidemiology, but data on its distribution and prevalence are lacking, mainly due to the limitations of clinical and coprological diagnosis in live horses. To overcome this constraint, a two-step, semi-nested PCR-based assay was validated (utilizing genetic markers in the nuclear ribosomal DNA) for the specific amplification of H. microstoma or H. muscae DNA from the faeces from ho...
Lawsonia intracellularis proliferative enteropathy in a weanling foal in Australia. A 6-month-old Quarter Horse weanling filly was presented with lethargy, weight loss, inappetance, mild diarrhoea, marked ventral oedema and severe panhypoproteinaemia. Serum antibody titres for Lawsonia intracellularis were very high but PCR to detect faecal shedding of the organism was negative. Proliferative enteropathy due to L. intracellularis infection was diagnosed. After treatment for 4 weeks with oral erythromycin and rifampicin the filly made a complete recovery.
