The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Slocombe JO, McCraw BM, Pennock P, Ducharme NG, Baird JD.Twenty pony foals (reared worm free), 6.5 to 10 weeks of age, were inoculated with Strongylus vulgaris and allocated to 5 groups, each with 4 foals. One week after inoculation, 1 group of 4 foals was given oxfendazole (OFZ) at a dosage rate of 10 mg/kg of body weight, another group was given 2 such treatments 48 hours apart, and a 3rd group was given a placebo. All treatments were administered by stomach tube. Three weeks later, foals were euthanatized and necropsied in a test for efficacy against early 4th-stage larvae. Oxfendazole was 80% and 94.9% effective against early 4th-stage S vulgari...
Reinemeyer CR, Herd RP.The large intestines of 6 horses were divided by length into 12 segments, and each segment was washed and weighed. At least 5% by weight of each segment was examined by mural transillumination, and encysted cyathostome larvae were counted. Total numbers of larvae in each segment were calculated. Encysted larvae (98%) were present in the proximal 7 segments of the large intestine (cecum and proximal 75% of the ventral colon), and 2% were present in the distal 25% of the ventral colon and entire dorsal colon. Encysted larvae (6%) were located in the dorsal colon of 1 heavily infected horse. Larv...
Martin L, Kaswan R, Chapman W.Traumatic optic nerve atrophy is characterised clinically by a unilateral or bilateral sudden onset of blindness. Dilated, fixed pupils and a lack of a menace reflex are the only abnormalities noted soon after the trauma. Within three to four weeks the optic disc becomes paler and the retinal vasculature is markedly decreased. The pathological lesion is a rupture of the nerve axons from stretching forces produced by the posterior movement of the brain against the fixed canalicular portion of the optic nerves. Medical therapy has not been successful.
Baggot JD, Love DN, Stewart J, Raus J.The absorption and disposition kinetics of gentamicin were compared at two dosage levels (2 and 4 mg/kg bodyweight [bwt]) in one- and three-month-old foals. Following intramuscular (im) injection of single 2 mg/kg bwt doses, the drug was absorbed rapidly and produced peak serum concentration (18.2 mu 5.3 +/- g/ml, n = 8) at 30 mins. Much wider variations were associated with the amount of drug absorbed and the serum gentamicin concentrations after administration at the higher dosage level. The half-life of gentamicin was similar in the one-month-old (3.7 +/- 1.7 h, n = 8) and three-month-old (...
Reinemeyer CR, Smith SA, Gabel AA, Herd RP.Monthly variations in the magnitude of adult and larval cyathostome burdens were observed in 55 horses necropsied over a 15-month period in the northern USA. Peak numbers of adult cyathostomes occurred in late winter (March) and late summer (September). Larval cyathostomes demonstrated peak numbers from February to April and again in October, beginning one month earlier than the spring adult peak and one month after the autumn adult peak, respectively. The reproductive status of individual female Cyathostomum catinatum, Cyath coronatum, Cylicocyclus nassatus, Cylicostephanus goldi and Cylicost...
Havelaar AH, Furuse K, Hogeboom WM.In an attempt to explain the presence of F-specific (RNA) bacteriophages in waste-water, faecal material from humans and a variety of animals was examined. The phages were detected in appreciable numbers only in faeces from pigs, broiler chickens, sheep and calves but not from dogs, cows, horses and humans. Parallel examinations for somatic coliphages, thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia revealed the consistent presence of these organisms in all types of samples, albeit in variable numbers. The number of F-specific bacteriophages was related...
Jacob RJ.Preliminary experiments have revealed that several laboratory and wild-type strains of the equine herpesvirus (EHV) triad were temperature-sensitive for growth when assayed at 39 degrees C. The efficiencies of plating (EOP) observed were 10(-2) for both EHV 1 and 2, and 1 X 10(-6) for EHV 3. The EOPs were determined by plaque assays which compared titrations at 34 degrees C and 39 degrees C on equine fetal dermal fibroblast cells. Growth yield experiments, assayed at 34 degrees C, reflected those EOP's, but did not indicate any difference in yields when infected cultures were incubated at 34 d...
Hultgren BD.Pulmonary lobar hypertrophy was diagnosed in a 4-hour-old Quarter Horse full-term foal that had respiratory arrest shortly after birth. The gross and microscopic appearances were consistent with polyalveolar lobe, a congenital anomaly of human infants.
Carroll JF, Schmidtmann ET.The American dog tick, Dermacentor variabilis (Say), was the only ixodid tick found feeding on horses in Montgomery County, Md., from May to August. Average tick burdens were low (less than one tick per horse per week), but >80% of 33 horses examined weekly were exposed to tick feeding during the summer. Of the 98 ticks collected, 78% were attached to the tail and 12% were present in the mane. Host-seeking adult D. variabilis were active on vegetation in pastures from May to early August, with most specimens along hedgerows, woods margins, and horse paths.
Voynick BT, Sweeney CR.Philippine polo and racing horses were examined for exercise-induced pulmonary hemorrhage after their competitive exercise. Exercise-induced pulmonary hemorrhage occurred in 11.1% of the polo horses and 64% of the racing horses. None of the horses had blood at the nostrils.
Smith JE, Cipriano JE, DeBowes R, Moore K.Values for serum ferritin, serum iron, and serum total-iron binding capacity were determined in 100 hospitalized horses. Six foals had iron deficiency, as indicated by low serum ferritin and iron concentrations. Twenty-eight horses had low serum iron content and normal or high serum ferritin content and were considered to have pseudo-iron deficiency, possibly in response to infection. Ten horses had serum ferritin concentrations that were quite high, probably indicating iron overload.
Richardson DW.Eikenella corrodens, a previously unrecognized pathogen in the horse, was isolated from the spinous process of the axis of a colt with signs of severe neck pain. Dorsal laminectomy (excising the infected spinous process and lamina) was performed and the colt was treated with antibiotics for 6 weeks. Recovery was uncomplicated.
Nation PN, Klavano GG.This account describes two neonatal foals affected with osteopetrosis. One of these foals, a full term Peruvian Paso, was born alive, was bright and alert but was unable to stand and was euthanized at two days of age. The second foal, an Appaloosa, was also born alive at full term and was blind, weak, uncoordinated and unable to stand. Postmortem examination of both foals revealed generalized osteopetrosis and brachygnathia inferior. The osteopetrosis was characterized by failure of bone remodelling resulting in spicules of mineralized and nonmineralized cartilage covered by osteoid occupying ...
Yager JA, Foster SF, Zink MC, Prescott JF, Lumsden JH.Polymorphonuclear leukocytes from adult horses were separated from whole blood, using a 2-step Percoll gradient, and were tested for bactericidal function against Corynebacterium equi. Staphylococcus aureus, an organism against which equine neutrophils have proved efficacy, was a positive control. The percentage of uptake after a 15-minute preincubation of the neutrophils and bacteria in the presence of normal horse serum was also calculated. The results indicated that equine neutrophils effectively phagocytosed and killed C equi and S aureus. The percentage of uptake for S aureus (95% +/- 3%)...
Gregory MW, Longstaff JA, Giles CJ.Ciliates resembling Polymorphella ampulla (Dogiel, 1929) were found in large numbers in the crypts and lamina propria of the caecum and colon of a one-year-old Thoroughbred gelding that had shown recurring bouts of chronic diarrhoea and weight loss over a 5-month period. A heavy burden of helminths, mainly cyathostomes (trichonemes) was present at post-mortem examination and no significant bacterial pathogens were recovered. It was considered that the Polymorphella (which is normally a commensal organism) had in this case assumed a secondary pathogenic role.
Frymus T, Kita J, Woyciechowska S, Ganowicz M.On 6 farms with a history of EHV-1 abortions the overall prevalence of losses due to abortion, stillbirth and neonatal foal mortality during 5 foaling seasons preceding the introduction of vaccination against EHV-1 were compared with corresponding data for 8 subsequent seasons in which all horses were immunized with a modified live EHV-1 vaccine. Although both sporadic and epizootic EHV-1 abortions occurred in immunized mares, the numbers of foetal and neonatal foal losses decreased significantly (chi 2 = 15.75; p less than 0.001) from 11.8% (343 of 2897 pregnancies) during the seasons 1969-19...
Magnuson N, Perryman L, Wyatt C, Mason P.Severe combined immunodeficiency (SCID) occurs in horses of the Arabian breed and is inherited as an autosomal recessive trait1. Affected foals are severely lymphopenic with an absence of functional B and T lymphocytes.2 The few lymphocytes that can be found in affected foals resemble large granular lymphocytes (LGL) and can be grown long-term with media containing interleukin-2 (IL-2).3 The disorder is restricted to the lymphoid system, as other leukocytes are functionally and quantitatively normal.4
Adeyefa CA, Tomori O, Akpavie SO, Awoseyi OA.Thirteen cases of a disease with a low morbidity and very high mortality in horses in Nigeria are described; the disease is characterised by fever (rectal temperature > or = 40 degrees C), generalised muscle spasms, ataxia, increased respiratory and heart rates and terminal lateral recumbency. The illness generally lasts three to five days but durations of 12 to 30 hours have been observed. Laboratory investigations, including histopathology and serology suggest a viral aetiology, possibly an alphavirus of the equine encephalitis group.