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Topic:Infectious Disease
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.
Detection of Cryptosporidium parvum in horses: thresholds of acid-fast stain, immunofluorescence assay, and flow cytometry. Feces collected from three asymptomatic horses and seeded with Cryptosporidium parvum oocysts (10(1) to 10(6)/g of feces) were evaluated by acid-fast staining (AF), an immunofluorescent antibody (IFA) technique, and flow cytometry. The thresholds of detection were 5 x 10(5) oocysts/g of feces for the IFA and AF techniques and 5 x 10(4) oocysts/g for flow cytometry.
Prevalence of beta2-toxigenic Clostridium perfringens in horses with intestinal disorders. The incidence of a new, yet unassigned toxin type of Clostridium perfringens containing the genes for the alpha-toxin and the recently described beta2-toxin in horses with intestinal disorders is reported. The study included 18 horses suffering from typical typhlocolitis, 7 horses with atypical typhlocolitis, 16 horses with other intestinal disorders, and 58 horses without intestinal disease. In total, 20 samples of ingesta of the small and large intestines, five biopsy specimens of the intestinal wall, and 74 fecal samples were analyzed bacteriologically. C. perfringens isolates were typed fo...
Diagnosis and prevention of equine infectious diseases: present status, potential, and challenges for the future. The frequent transfers of horses, whether on a permanent or temporary basis, make strict control of infectious diseases essential. Such control needs a reliable and rapid means to accurately diagnose the relevant diseases. Indirect diagnosis based on antibody detection remains certainly the best method to secure the epidemiologic surveillance of the diseases at regional, national, or even world level, while direct diagnosis is the only way to diagnose a new outbreak. New diagnostic methods resulting from advances in biochemistry, molecular biology, and immunology are now available. As far as a...
Evaluation of equine infectious anemia virus core proteins produced in a baculovirus expression system in agar gel immunodiffusion test and enzyme-linked immunosorbent assay. Equine infectious anemia virus (EIAV) core proteins (Gag and p26) obtained from a baculovirus expression system were used in agar gel immunodiffusion (AGID) and enzyme-linked immunosorbent assay (ELISA) antigens to test seventy-six horse sera. Those sera showed false-positive reaction in AGID test using Nisseiken antigen. However, none of them showed false-positive reaction with both of the expressed antigens. The 76 horse sera were also tested by ELISA. The sera gave a high background in ELISA using Nisseiken antigen. Gag and p26 reacted strongly against positive sera from horses immunized wi...
Enzyme-linked immunosorbent assay (ELISA) for detection of anti-Trypanosoma evansi equine antibodies. The standardization of ELISA for the detection of anti-Trypanosoma evansi antibodies in naturally and experimentally infected horses is described. Bayesian analysis was used to establish the cutoff between positive and negative sera. In order to determine the assessment of the ELISA test, the results obtained were compared with those from an IFA. A relative sensibility of 98.39%, a specificity of 95.12% and a predictive value of 96.83% were determined. The standardized technique was used to evaluate the antibody production against trypanosome in an experimentally infected equine, in which the ...
Suppressant effect of human or equine rabies immunoglobulins on the immunogenicity of post-exposure rabies vaccination under the 2-1-1 regimen: a field trial in Indonesia. MAS054 Clinical Investigator Group. WHO's reference protocol for post-exposure rabies vaccination advises five intramuscular injections on days 0, 3, 7, 14, and 30; in addition, rabies immunoglobulins (RIG) must be given to serious cases of exposure (grade III severity). Some studies indicate that these immunoglobulins suppress the immunogenicity of rabies vaccine when administered according to an alternative protocol of four injections (2-1-1) on days 0, 7, and 21, which was therefore not recommended for grade III exposures. To test this effect, we conducted a multicentre study in Indonesia using three groups of subjects. One g...
Observations on African horse sickness in Saudi Arabia. The present epidemiological status of African horse sickness in Saudi Arabia, as shown by seroconversion, virus isolation and clinical observation of sentinel horses is described. No African horse sickness virus activity was detected throughout the duration of the study (from November 1992 to March 1995). These findings support previous reports that African horse sickness is not endemic in Saudi Arabia.
A review of leptospirosis in farm animals in Portugal. This paper presents a review of Leptospira infection in farm animals in Portugal which is based mainly on serological results obtained in the National Veterinary Research Laboratory between January 1987 and December 1993. Serum samples were tested by the microscopic agglutination test, at a minimum dilution of 1:100. Positive titres were obtained in 15.3% of the 9,543 bovine samples examined. Sejroe, Pomona, Hebdomadis, Tarassovi and Icterohaemorrhagiae were the principal serogroups which reacted in the tests. A total of 3,195 pigs were tested, of which 20.2% showed positive reactions. The mai...
Effect of moderate exercise on the severity of clinical signs associated with influenza virus infection in horses. The purpose of this experiment was to determine if exercising horses, infected with influenza virus, exacerbates the severity of clinical disease. Eight horses were trained on a treadmill for 42 days and then challenged with aerosolised influenza A/equine/Kentucky/91 (H3N8). Following challenge, 4 horses (exercise group) continued training for 28 days, while the other 4 horses (nonexercise group) were confined to their stalls. All horses developed clinical signs within 36 h of challenge (fever, coughing, and mucopurulent nasal discharge) and clinical scores were greater in the exercise group. ...
Endoscopic treatment of suspected infectious intertubercular bursitis in a horse. A 9-year-old gelding was evaluated because of a 30-day history of mild intermittent left forelimb lameness. The only detectable abnormality was mild atrophy of the musculature of the proximal portion of the left forelimb. The cause of the lameness could not be determined. The horse was discharged from the hospital, but was reexamined 6 weeks later because of worsening of the lameness. At that time, the horse resisted flexion and extension of the left shoulder joint, and results of evaluation of an ultrasound-guided aspirate of fluid from the intertubercular bursa were suggestive of infection. ...
Systemic infection by equid herpesvirus-1 in a Grevy’s zebra stallion (Equus grevyi) with particular reference to genital pathology. A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto u...
Seroprevalence of equine herpesvirus 1 in thoroughbred foals before and after weaning. To investigate the seroprevalence of equine herpesvirus 1 in foals around weaning and after weaning on two large Thoroughbred farms using a type-specific enzyme-linked immunosorbent assay to determine exposure to infection. Methods: A longitudinal population study in groups of Thoroughbred weanling foals. Methods: Two hundred weanling Thoroughbred foals from a population of about 380 foals were enrolled on two adjacent stud farms in the Hunter Valley of New South Wales. Foals on both farms were weaned from February to May 1995 into randomly selected groups of 10 to 15 foals. Farms were selecte...
Equine infectious anemia virus Gag polyprotein late domain specifically recruits cellular AP-2 adapter protein complexes during virion assembly. We have identified an interaction between the equine infectious anemia virus (EIAV) late assembly domain and the cellular AP-2 clathrin-associated adapter protein complex. A YXXL motif within the EIAV Gag late assembly domain was previously characterized as a sequence critical for release of assembling virions. We now show that this YXXL sequence interacts in vitro with the AP-50 subunit of the AP-2 complex, while the functionally interchangeable late assembly domains carried by the Rous sarcoma virus p2b protein and human immunodeficiency virus type 1 p6 protein, which utilize PPPY and PTAPP ...
Enterotoxigenic Clostridium perfringens type A necrotic enteritis in a foal. A Thoroughbred-Quarter Horse crossbred foal developed hemorrhagic enteritis and died < 48 hours after birth. Gross and histologic findings were suggestive of Clostridium perfringens type C infection, and large numbers of C perfringens were isolated from intestinal contents. However, genotyping of isolates indicated that they were enterotoxigenic C perfringens type A, and isolates were found to produce C perfringens enterotoxin in vitro. This case suggests that enterotoxigenic C perfringens type A may cause enteric disease in horses.
Public veterinary medicine: public health. Serologic evaluation of vesicular stomatitis virus exposure in horses and cattle in 1996. To determine potential risk factors for vesicular stomatitis (VS) in Colorado livestock in 1995 and evaluate VS virus (VSV) exposure of Colorado livestock in 1996. Methods: Retrospective case-control study of VS risk factors and seroprevalence evaluation. Methods: Premises included 52 that had VS-positive animals and 33 that did not have VS-positive animals during the 1995 epidemic, and 8 in the vicinity of premises that had VS-positive animals during the 1995 epidemic. Methods: Layout and management data for premises were collected during site visits in 1996. Signalment and management data we...
Enzyme-linked immunosorbent assay for serological survey of equine arteritis virus in racehorses. To examine antibodies against equine arteritis virus (EAV), an enzyme-linked immunosorbent assay (ELISA) using purified virus antigen was developed. The results of ELISA were compared with those of serum neutralization (SN) tests. The ELISA absorbance values and the SN titers in sera collected weekly from EAV-infected horses showed a similar pattern. The ELISA could detect antibody to EAV in horses experimentally infected with not only a homologous virus strain, which was used as the ELISA antigen, but also a heterologous strain. Using the ELISA, serum samples collected in 1996 from racehorses...
Pathogenicity of Vibrio alginolyticus for cultured gilt-head sea bream (Sparus aurata L.). The in vivo and in vitro pathogenic activities of whole cells and extracellular products of Vibrio alginolyticus for cultured gilt-head sea bream were evaluated. The 50% lethal doses ranged from 5.4 x 10(4) to 1.0 x 10(6) CFU/g of body weight. The strains examined had the ability to adhere to skin, gill, and intestinal mucus of sea bream and to cultured cells of a chinook salmon embryo cell line. In addition, the in vitro ability of V. alginolyticus to adhere to mucus and skin cells of sea bream was demonstrated by scanning electron microscopy. The biological activities of extracellular produc...
Description of a new Neospora species (Protozoa: Apicomplexa: Sarcocystidae). Neospora hughesi n. sp. was isolated from the central nervous system tissue of an adult equine (Equus caballus) from California. The tachyzoites are crescent-shaped, approximately 2 x 5 microm (1.8-3.0 x 4.0-7.0 microm), with characteristic apical complex structures consisting of an anterior polar ring, conoid, numerous rhoptries filled with a uniform electron-dense material, and 22 microtubules extending posteriorly from the polar ring. Comparison of N. hughesi to canine and bovine Neospora caninum isolates showed phenotypic differences in immunoreactive proteins. Molecular analysis of the sm...
Animal models of pneumocystosis. As in vitro culture systems allowing to isolate Pneumocystis samples from patients or other mammal hosts are still not available, animal models have critical importance in Pneumocystis research. The parasite was reported in numerous mammals but P. carinii pneumonia (PCP) experimental models were essentially developed by using rats, mice, rabbits and ferrets. The rat treated with corticosteroids for 9-12 weeks is a useful PCP model. Like laboratory rats, conventional mice develop PCP after prolonged corticosteroid administration. The ferret (Mustela putorius furo) also develop PCP under cortico...
Coprological methods for the diagnosis of Anoplocephala perfoliata infection of the horse. To compare the sensitivities of three coprological techniques for the diagnosis of Anoplocephala perfoliata infection in horses and to assess the value of the methods for diagnosis of horses at risk of clinical cestodiasis. Methods: Faecal samples were collected from necropsied horses with or without A perfoliata infection and examined using one sedimentation and two different flotation methods. The coprological results were compared with worm counts performed at necropsy of the horses and the degree of mucosal damage. In addition, the efficiency of recovery of A perfoliata eggs from faeces wa...
Persistence of the efficacy of a moxidectin gel on the establishment of cyathostominae in horses. A controlled trial was carried out to evaluate the persistence of the effect against small strongyles of a 2 per cent moxidectin gel administered orally to foals at a dose rate of 0.4 mg/kg bodyweight. Five of nine helminth-free foals were treated on day 0, and the remaining four foals were used as controls. On days 0, 7, 14, 21 and 28 all nine foals were infected experimentally with 200,000 small strongyle larvae. Three treated and two control foals were necropsied on day 42 and the rest on day 43. Fourteen species of small or medium sized small strongyles were found in the control foals, 10 ...
Experimental infection of four horses with Ehrlichia phagocytophila. Four clinically healthy horses which were negative for antibodies to Ehrlichia phagocytophila, the agent of bovine ehrlichiosis, were infected experimentally with E phagocytophila-containing bovine leucocytes, administered intravenously. The horses were examined daily for four weeks, and blood samples were collected daily for cytological, haematological and biochemical examination and for a nested polymerase chain reaction (PCR). An indirect immunofluorescence test was used to determine when the horses seroconverted and the duration of positive titres. There were no abnormal clinical, haematol...
Influence of fecal shedding of Salmonella organisms on mortality in hospitalized horses. To predict mortality of horses by use of clinical data from the first day of hospitalization, to determine whether fecal shedding of Salmonella organisms is related to severity of clinical disease, and to determine the impact of fecal shedding of Salmonella organisms on mortality. Methods: Prospective study. Methods: 1,446 hospitalized horses. Methods: Medical information was obtained from horses hospitalized in an intensive care unit or isolation facility during a 4.5-year period. A model was created to predict mortality, using covariates determined on the day of admission. Predicted mortalit...
Actinobacillus and Pasteurella species isolated from horses with lower airway disease. Seventy-three bacterial isolates from 65 horses with and without evidence of lower airway disease were identified to assess whether the association with disease was accounted for by a small or large number of species. Just over half (50.5 per cent were Actinobacillus equuli, 17.8 per cent were A suis-like, 11 per cent were Pasteurella pneumotropica, 8.2 per cent were A lignieresii, 6.8 per cent were P haemolytica and 5.5 per cent were P mairii. These results suggest that a range of Actinobacillus and Pasteurella species can be isolated from the lower airways of horses, with many of the isolate...
