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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.
Recent vesicular stomatitis virus infection detected by immunoglobulin M antibody capture enzyme-linked immunosorbent assay. We developed an enzyme-linked immunosorbent assay (ELISA) that was capable of detecting immunoglobulin M (IgM) antibody to vesicular stomatitis virus (VSV) in the sera of experimentally and naturally infected cattle and horses. The detection of IgM in the sera of these animals permitted an estimate of the recency of infection by VSV serotype New Jersey. A VSV serotype New Jersey epizootic strain isolated from a horse and passed once in an Aedes albopictus cell line was used to infect a horse and a calf. Sera from these animals were used to standardize the ELISA. This assay was used to test ser...
Studies on equine recurrent uveitis. II: The role of infection with Leptospira interrogans serovar pomona. An enzyme linked immunosorbent assay was developed for the detection of immunoglobulin class specific antibodies to Leptospira interrogans serovar pomona in the serum and aqueous humor of horses. Serum antibody was also assayed by microscopic agglutination tests. Although higher levels of antibody were found in sera from horses with signs of uveitis, the association was not statistically significant. Antibodies to pomona were detected in the aqueous of 12 eyes from the 101 horses sampled at a slaughterhouse, and in most instances, a comparison of the aqueous/serum antibody level with that of t...
Studies on equine recurrent uveitis. I: Levels of immunoglobulin and albumin in the aqueous humor of horses with and without intraocular disease. A radioimmunoassay was developed for detection of immunoglobulin in the aqueous of normal horses and horses with intraocular diseases. Levels of albumin were detected by radial immunodiffusion. Results of assays on samples from normal eyes from which aqueous was obtained by paracentesis under anesthesia were 32.10 +/- 21.50 microgram/ml for IgG, 0.05 +/- 0.01 microgram/ml for IgM, 0.04 +/- 0.02 microgram/ml for IgA and 34.0 +/- 38.0 microgram/ml for albumin. Results in 138 normal eyes sampled post mortem were 41.56 +/- 38.65 microgram/ml for IgG, 0.18 +/- 0.43 microgram/ml for IgM, 0.46 +/- 1....
Effect of intrauterine infusion of Escherichia coli endotoxin in postpartum pony mares. Fifteen pony mares were assigned to 1 of 3 treatment groups after foaling: Group 1, 35 ml of sterile saline solution was infused into the uterine lumen within 24 hours after parturition (6 mares); group 2, 300 mg of Escherichia coli endotoxin was infused into the uterine lumen within 24 hours after parturition (6 mares); and group 3, 300 mg of E coli endotoxin was infused into the uterine lumen between 72 and 96 hours after parturition (3 mares). Rectal temperatures were taken at -1, -0.5, 0, 0.5, 1, 1.5, 2, 3, 4, and 5 hours after treatment. Venous blood samples were also taken at these times...
Studies on the immunogenicity of Streptococcus equi vaccines in foals. The ability of either formalin-treated or heat-inactivated whole Streptococcus equi cell vaccines or partially purified M-protein of S. equi to give rise to protective antibody levels was studied in Standardbred foals by serological means. Two commercial preparations, i.e. a beta-propiolactone killed whole S. equi cell bacterin and a cell-free extract of S. equi cells were included in the study. The mean passive hemagglutination antibody titers (10 X log2) in sera of foals given either four doses of formalin-treated whole cell vaccine or an initial dose of formalin-treated followed by three do...
In vitro phagocytosis and killing of Corynebacterium equi by alveolar macrophages of foals. Bronchoalveolar lavage was performed 5 times, sequentially, on 3 healthy foals while each foal was 6 to 63 days of age. Phagocytosis and bactericidal assays were performed on recovered alveolar macrophages. Corynebacterium equi and alveolar macrophages at a ratio of 10:1 were incubated for 1 hour in medium containing 1% heat-inactivated rabbit anti-C equi serum. After incubation, greater than 90% of the alveolar macrophages contained at least 1 ingested bacterium and each alveolar macrophage contained 9.4 +/- 1.0 bacteria (mean +/- SE). After alveolar macrophages and C equi were incubated for ...
Isolation of non-O1 Vibrio cholerae associated with enteric disease of herbivores in western Colorado. Non-O1 Vibrio cholerae was isolated from a horse (Equus caballus), a lamb (genus Ovis), and two American buffalo (Bison bison) suffering from enteric disease in the western part of Colorado. In 1981, a foal died of apparent respiratory failure. Necropsy findings included heart failure and gastroenteritis. V. cholerae serovar 347 (Smith) was isolated from the colon of this animal. V. cholerae serovar 27 (Smith) was isolated in 1983 from the intestine of a feedlot lamb suffering from pneumonia and severe watery diarrhea. In 1984, an enteric disease occurred in a herd of American bison. The sick ...
Retropharyngeal infections in five horses. Five horses with retropharyngeal (RP) infections had clinical signs of dysphagia and/or dyspnea. Diagnosis was confirmed, using pharyngeal endoscopy and lateral radiography of the pharynx. One horse responded to surgical drainage of a RP abscess and was sound at light work. One horse responded to medical management after the site of infection was surgically explored. Two horses recovered after medical management; the RP abscess of 1 of these 2 horses ruptured spontaneously into the pharynx and the other horse became racing sound. The fifth horse remained dysphagic and had left laryngeal hemipl...
Serum antibodies to Leptospira bratislava in Swedish pigs and horses. Sera from 116 and 89 Swedish pigs and horses respectively were examined for the presence of antibodies to L. bratislava. Antibodies were found in 18.1 and 49.4% respectively of pigs and horses examined. Presence of serum antibodies was not associated with clinical signs of infection.
Micronema granuloma in the gingiva of a horse. A well-circumscribed proliferative mass was protruding from the body of the mandible of a 4-year-old Appaloosa gelding. The mass was uniformly firm and was ulcerated on the dorsal surface. The horse was euthanatized due to extensive involvement of the jaw and difficulty in eating. Microscopically, the mass consisted of numerous discrete microgranulomas separated by bands of abundant fibrous connective tissue containing lymphocytes, plasma cells, and histiocytic macrophages. Numerous rhabditiform nematodes were in the microgranulomas as well as in the surrounding connective tissue. The nematode...
Isolation of equine coital exanthema virus (equine herpesvirus 3) from the nostril of a foal. The virus causing equine coital exanthema (equine herpesvirus 3) was isolated from a lesion on the nostril of a 2-month-old foal. One week after the mare had returned from a stallion station, vesicular lesions developed on her vulva. They were diagnosed clinically as coital exanthema, and 5 days later a lesion developed on the nostril of her foal. This case is an example of horse-to-horse transmission of coital exanthema virus without coitus. A laboratory diagnosis is necessary to differentiate viruses that cause vesicular lesions about the oral and nasal cavities of horses.
Perirectal abscesses in six horses. Perirectal abscesses were diagnosed retrospectively in 6 horses treated for colic. The abscesses caused colic in the horses by producing an extraluminal obstruction that led to fecal impaction. The abscesses were diagnosed by rectal palpation and aspiration of exudate from the masses and were drained surgically. In horses in which the abscess involved abdominal organs, peritonitis developed.
Anti-lipopolysaccharide toxin therapy for whole body X-irradiation overdose. Death in humans from ionising radiation overexposure in the 3-8 Gy (300-800 rad) range is in part due to the toxaemia caused by the entry of gram-negative bacteria and/or their lipopolysaccharide toxin (LPS) into the blood circulation through the walls of partially denuded gut. Anti-LPS hyperimmune equine plasma was evaluated for its ability to lower irradiation-induced lethality. Mice were irradiated with 6.3 Gy (630 rad) and six days later received equine Anti-LPS hyperimmune plasma, control plasma or saline. Mortalities in the three groups were 58%, 92% and 79% (p less than 0.01) respective...
Experimental reactivation of equid herpesvirus 1 (EHV 1) following the administration of corticosteroids. Eight ponies were experimentally infected with equid herpesvirus 1 (EHV 1) (subtype 1). All animals showed clinical and serological evidence of infection and virus was isolated from nasal swabs and leucocytes. These ponies were kept in isolation for a further three months during which time complement fixing antibody decreased at least four-fold. Following immunosuppression with dexamethasone and prednisolone subtype 1 virus was recovered from six of the eight animals within 14 days. Five of these six ponies were viraemic and three of them shed virus in nasal secretions; only four displayed sig...
Causative ehrlichial organisms in Potomac horse fever. An ehrlichia was consistently isolated from the peripheral blood leukocyte fraction of ponies that had been experimentally infected with Potomac horse fever by whole blood transfusion from naturally infected horses. The organism was propagated in a human histiocyte cell line for 3 to 5 weeks and then inoculated intravenously or intradermally into healthy adult ponies. Clinical signs of Potomac horse fever, which varied in the degree of severity, occurred 9 to 14 days post-inoculation in all of the ponies. One pony died 20 days post-inoculation. The ehrlichial organism was reisolated in the hum...
Phagocytic and killing capacities of uterine-derived polymorphonuclear leukocytes from mares resistant and susceptible to chronic endometritis. The host defense competence of uterine-derived polymorphonuclear leukocytes (PMN) from mares considered resistant (grade I uteri) and susceptible (grade III uteri) to chronic endometritis was evaluated for phagocytic and killing (bactericidal) capacities, using a fluorochrome assay. Peripheral blood PMN from noncategorized mares and from grade I and grade III mares were used as controls. Uterine-derived PMN from mares with grade I uteri were functionally competent for phagocytosis and killing of Candida albicans, whereas uterine-derived PMN from mares with grade III uteri had significantly les...
Arbovirus investigations in Argentina, 1977-1980. IV. Serologic surveys and sentinel equine program. Serologic surveys of wild and domestic birds, wild mammals, and horses were conducted during arbovirus field studies in Argentina from 1977 through 1980, a non-epizootic interval. The prevalence of neutralizing antibodies to eastern equine encephalitis (EEE) was consistently higher than to western equine encephalitis (WEE) virus in all species and all areas. The presence of antibodies in short-lived avian species and in young unvaccinated horses and the demonstration of seroconversions in horses during the period, indicated that these viruses are either enzootic in, or annually reintroduced in...
Powassan viral encephalitis: a review and experimental studies in the horse and rabbit. Powassan virus strain M794, a member of the Flavivirus genus known to infect man and animals in Canada, was inoculated intracerebrally into rabbits and horses. No clinical signs were observed in rabbits, but widespread encephalitis resulted, characterized by lymphoid perivascular cuffing, lymphocytic meningitis, and lymphocytic choroiditis. In horses, eight days after inoculation, prominent neurological signs occurred and lesions were those of non-suppurative encephalomyelitis, neuronal necrosis, and focal parenchymal necrosis. The virus could not be reisolated from the rabbit or horse brains....
Ultrastructural study of ehrlichial organisms in the large colons of ponies infected with Potomac horse fever. Potomac horse fever is characterized by fever, anorexia, leukopenia, profuse watery diarrhea, dehydration, and high mortality. An ultrastructural investigation was made to search for any unusual microorganisms in the digestive system, lymphatic organs, and blood cells of ponies that had developed clinical signs after transfusion with whole blood from horses naturally infected with Potomac horse fever. A consistent finding was the presence of rickettsial organisms in the wall of the intestinal tract of these ponies. The organisms were found mostly in the wall of the large colon, but fewer organ...
Upper respiratory tract obstruction caused by a pharyngeal abscess in a filly. A 3-year-old Thoroughbred filly had a pharyngeal abscess causing obstruction of the upper respiratory tract. Diagnosis was made by a combination of endoscopy, biopsy, cytology, and radiography. Treatment with antimicrobials and analgesics resulted in successful resolution of the abscess.
Use of cancellous bone graft in treatment of navicular bone osteomyelitis in a foal. A 3-month-old Quarter Horse filly stepped on a fence staple and developed navicular bone osteomyelitis of the right hindfoot. A 1.5-cm spherical portion of medullary cavity containing purulent material was debrided and flushed with 0.9% NaCl solution. Cancellous bone was collected from a caudal sternebra and placed into the defect. The solar defect had filled with granulation tissue and was epithelialized 6 weeks after surgery. At 6-month follow-up evaluation, the navicular bone defect had healed and the foal was sound on the limb. Cancellous bone grafting may have merit for the treatment of n...
Persistence of encysted Toxoplasma gondii in tissues of equids fed oocysts. Thirteen 6-month- to 13-year-old equids were each inoculated orally with 10,000 infective Toxoplasma gondii oocysts. The equids remained clinically normal. Equids were euthanatized on postinoculation days 33, 45, 90, 104, 120, 140, 162, 183, 197, 204, 211, 294, and 476. Their tissues were bioassayed for viable oocysts by feeding muscles to Toxoplasma-free cats and by inoculation of pepsin digests of 13 organs into mice. Using mouse inoculation, T gondii was recovered from tissues of the 9 equids euthanatized on each of postinoculation days 33, 45, 120, 140, 183, 197, 211, 294, and 476. Toxopla...
The use of the glutaraldehyde coagulation test for detection of hypogammaglobulinaemia in neonatal foals. The effectiveness of the glutaraldehyde coagulation test (GCT) in detecting failure to acquire colostral immunoglobulin in neonatal foals was investigated. This was achieved by comparing and correlating results from the GCT with those obtained by single radial immunodiffusion (SRID) of equine IgG. The GCT was found to be a practical, inexpensive, semiquantitative test with a high specificity and sensitivity at critical IgG levels.
Pathogenesis of helminths in equines. This review summarizes information on the clinical signs, gross and microscopic lesions associated with nematode and cestode infections and discusses the development of these conditions in the equine host.
Salmonella shed by horses with colic. Salmonella was isolated from 13 of 100 colicky horses admitted to a referral hospital. Seven horses were shedding the microorganism at or soon after hospital admission. A unique serotype was introduced into the hospital by a horse not shedding Salmonella at admission. It was concluded that 8 horses were infected before admission. Whether the remaining 5 horses were infected before or after admission could not be determined. Salmonella senftenberg was the most commonly isolated serotype from colicky horses and from horses with salmonellosis that were not colicky on hospital admission during the...
