Topic:Pathogens
Pathogens are microorganisms, such as bacteria, viruses, fungi, and parasites, that can cause disease in horses. These microorganisms interact with the equine immune system, often leading to a range of health issues that can affect individual horses or entire populations. Pathogens can be transmitted through various routes, including direct contact, vectors, or environmental exposure. Common equine pathogens include Streptococcus equi, Equine Herpesvirus, and Strongylus vulgaris. Understanding the interactions between equine hosts and pathogens is essential for disease prevention, management, and treatment. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, transmission, and impact of pathogens on equine health.
Ultrastructure of Haemophilus equigenitalis, causative agent of contagious equine metritis. Haemophilus equigenitalis, a proposed new species of Haemophilus and the causative agent of contagious equine metritis, a venereal disease of the horse, had ultrastructural characteristics of gram-negative bacteria. The organism additionally had a small, threadlike capsule that was removed by heating in phosphate-buffered saline solution. Heating also detached the outer membrane from the cytoplasmic membrane. The capsule could only be demonstrated when bacterial were stained with ruthenium red during the preparation of ultrathin sections. The gross morphology of newly isolated organisms (rodli...
Persistence in nature of influenza virus A/eq/Praha/56 (Heq1Neq1). Equine influenza occurred in Czechoslovakia 14 years after the last epizootic in horses that had returned from abroad. Six strains A (Heq1Neq1) antigenically related to, but not identical with, strain A/eq/Praha/56 were isolated from 10 washings. Seroconversion was demonstrated with paired sera, but the antibody increase was more marked against the newly isolated strain.
Dynamic changes of horse serum T-globulin immunization with snake venoms, tetanus and diphtheria toxoids. In course of immunizing horses with snake venoms, tetanus and diphtheria toxoids, a new serum component, T-globulin, was formed and migrated between the beta- and gamma-globulins. The T-globulin content was parallel with the antibody titre after the middle course of immunization. There were many components in snake antivenin and T-globulin was composed of most of those components. The components of diphtheria T-globulin were the same as those of crude antitoxin and tetanus T-globulin except one precipitin.
The epidemiology of ringworm in racehorses caused by Trichophyton equinum var autotrophicum. The epidemiology of dermatomycocis due to Trichophyton equinum var autotrophicum was studied in a number of thoroughbred stables in south-east Queensland. The significant factors in the epidemiology were defined. The infection was readily transmitted, particularly by infected saddle-girths, on which the fungus could survive for 12 months. Mild abrasion from the saddle during work favoured the development of lesions and prolonged the recovery period. A pronounced age and seasonal incidence of the disease was demonstrated as young horses under the age of 3 years were most susceptible, and the ma...
Pleasure horses as a possible source of Salmonella agona. Horses in a riding stable sporadically excreted Salmonella agona, S anatum, and S newington in the feces. The three serotypes were isolated from apparently normal horses. The horses were sampled (the number sampled varied between 10 and 21) six times throughout a 13-month period. The greatest percentage of the horses (12 of 19, or 63%) were found to be excreting salmonella in September. Among the 12 horses excreting salmonella during this month, 8 (67%) were found to be excreting S agona.
Survival of contagious equine metritis bacteria in transport media. 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...
Selective medium for Corynebacterium equi isolation. The development of a selective medium for the isolation of Corynebacterium equi is described. The medium has been used to examine fecal samples from 127 horses of which 90 have been found to carry the organism.
Isolation of Klebsiella pneumoniae from the urogenital tract of experimentally infected mares. K. pneumoniae capsule type 68 infused into the uterus of 4 mares was recovered up to 15 weeks after inoculation. The insertion of a tampon for 10 min was more effective than a swab technique in detecting the organism in the uterus. The clitoral fossa and the urethral orifice when sampled by the swab technique were also found to be infected for a comparable period. K. pneumoniae was isolated from the clitoral specimens more often and more consistently than from either urethral or uterine specimens.
Hepatic pathology of experimental Parascaris equorum infection in worm-free foals. The pathological changes associated with the migration through the liver of P. equorum larvae were investigated. Twenty pony foals were killed at intervals of 2 to 185 days after a single infection with 160 or 8000 P. equorum eggs and 4 pony foals were killed at intervals of 94 to 144 days after twice weekly infections of 50 eggs from birth. At post-mortem examination the macroscopic changes included the development of focal haemorrhages and small, white diffuse or nodular lesions.
Microscopic lesions were found mainly around the portal triads and consisted of infiltration by cells, including...
A comparative study of bovine herpesvirus 1247 and equine herpesvirus 1 in ponies. The clinical and immunological response of ponies exposed to a bovine herpesvirus isolate and equine herpesvirus 1 were compared. Each virus was inoculated into two ponies by the intranasal route. One uninoculated pony was used with each group as a contact control. The four inoculated ponies developed a mild rhinitis with an increase in rectal temperature. Virus was recovered from nasal secretions collected from the four inoculated and one contact pony. All ponies developed a serum neutralizing antibody to each virus. The data show that the two viruses are similar.
The bacteriological culture of equine uterine contents, in-vitro sensitivity of organisms isolated and interpretation. A total of 19 pathogenic bacterial species was isolated from uterine swabs of 498 out of 1539 mares over 4 years. The swabs were taken by 5 veterinary clinicians using 2 different techniques. Bacterial contamination during swabbing was minimized by scrupulous attention to cleansing of the external genitalia and the perineal area, and in the handling of the culture specimen. The most prevalent organisms isolated were beta-haemolytic streptococcus (39%), Escherichia coli (27%) and Klebsiella pneumoniae (7%). Interpretation of microbiological findings correlated well with clinical findings when n...
A study of the specificity of Bandeiraea simplicifolia lectin I by competitive-binding assay with blood-group substances and with blood-group A and B active and other oligosaccharides. The specificity of Bandeiraea simplicifolia lectin I (BS I) has been studied by competitive-binding assays (CBA) using tritium-labeled human B and hog A substances. Blood-group B substances isolated from horse gastric mucosae and from human ovarian-cyst fluids were much better inhibitors of binding of tritiated blood-group B substance to insoluble BS I-Sepharose 2B than were human blood-group A substances from saliva and ovarian-cyst fluid. A and B active blood-group substances showed the same range of potency in inhibiting binding of tritium-labeled hog A substance to BS I-Sepharose 2B. CBA w...
Enterotoxemia in two foals. Two Quarter Horse foals from different premises died from enterotoxemia. Clostridium perfringens toxins alpha and beta were demonstrated in the foal's intestines by mouse protection tests. Clostridium perfringens type C was isolated from the intestines of each foal. Histologic examination revealed hemorrhage, necrosis, and massive numbers of C perfringens.
Rates of infection in, and transmission of, African horse-sickness virus by Aedes aegypti mosquitoes. Very low infection rates (less than 3%) were obtained when Aedes aegypti mosquitoes ingested blood contained 5.8--6.5 log10 MLD50/0.02 ml African horse sickness virus (AHSV). When A. aegypti mosquitoes were inoculated intrathoracically with virus, however, high infection rates were achieved. Mosquitoes infected by inoculum failed to transmit virus to embryonated hens eggs by bite, and virus could not be detected in membrane or blood when inoculated mosquitoes were allowed to engorge on uninfected blood through a chick skin membrane. It was concluded that the mosquito A. aegypti is unlikely to ...
Characterization of haemolytic streptococci isolated from horses and cattle. No abstract available
Further characterization of Listeria monocytogenes serotype 5. Fifteen strains of Listeria monocytogenes serotype 5 were characteriized for carbohydrate utilization, enzymic reactions, and other differential criteria. Hemolytic patterns were tested on ovine, bovine, equine, human and lapine blood agars. Results were compared with those of previously reported strains of L. monocytogens serotype 5.
Some studies on equine strains of Escherichia coli. A detailed study was made of 194 equine strains of E. coli, involving biochemical and serological characters. In these, the equine strains closely resembled E. coli from other sources, and shared antigenic characters with strains isolated from different animal species.
Metastatic phycomycosis in a horse. Extensive subcutaneous phycomycosis of the lower hindlimb developed over a period of 8 months in a Thoroughbred filly. There was no response to treatments such as trichlorphon, sodium iodide, or etisazole. Extension of the limb lesion over the following 3 months was associated with an enlarged inguinal lymph node, which was removed. Characteristic phycomycotic lesions were observed in the node, and a fungus having the morphologic features of Hyphomyces destruens was isolated from both the limb and nodal lesions.