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.
McQueary CA, Worley DE, Catlin JE.Of 22 foals from 4 localities in southwestern Montana, 59% were found to be infected with Eimeria leuckarti. Oocysts collected from feces of 4 positive horses were sporulated and subsequently administered to a 5- to 6-month-old foal. The prepatent period was 31 days and the patent period was between 5 and 10 days.
Dutta SK, Campbell DL.Blastic transformation of peripheral blood mononuclear cells and serum neutralization antibody levels for equine herpesivurs type 1 were measured in 19 mares from three farms at the time of termination of their pregnancy by normal foaling or viral abortion. The stimulation indexes of lymphocytes obtained from the mares from two farms (Farm 1 and 2) which had virus abortions, ranged from 2.1 to 10.8. But there was no significant difference in stimulation index levels between the aborting and normal foaling mares on these two farms. Equine herpesvirus type 1 was isolated from the mononuclear cel...
Greatorex JC.The clinical manifestations, diagnosis and differential diagnosis of "verminous aneurysm" formation at the root of the cranial mesenteric artery and coeliac artery resulting from Strongylus vulgaris larvae migration are described. Forty-nine of 57 cases were successfully treated with low molecular weight dextran (dextran 70).
Jahrling PB, Beall JL.Hydroxylapatite column chromatography methods were developed to characterize selected alphavirus populations. Different conditions of pH and phosphate molarity were required to obtain satisfactory elution profiles and separations for Western equine encephalomyelitis virus strains, compared with Eastern equine encephalomyelitis virus and Semliki Forest virus strains. Raising the pH of the buffers effected earlier elutions of all viruses. Selection of phosphate gradients with more gentle slopes and adjustment to the proper pH effected better separations of virus subpopulations. Elution profiles ...
Rumbaugh GE.Physical, neurologic, and clinicopathologic findings in a 3-year-old female Morgan horse with anorexia and nasal discharge suggested suppurative meningitis. Necropsy findings substantiated the tentative diagnosis. Actinomyces sp was cultured from a meningeal abscess surrounding the pituitary gland and from resolving lung abscesses.
Verma BB, Biberstein EL, Meyer ME.A serologic survey was made of the prevalence of common leptospiral infections in horses in California. A total of 465 serums were tested, using the microscopic agglutination method, against 5 leptospiral serotypes: Leptospira pomona, Leptospira icterohaemorrhagiae, Leptospira canicola, Leptospira grippotyphosa, and Leptospira hardjo. Of the serums tested, 127 (27.30%) were positive against 1 or more of the leptospires, with percentage distribution among the reactors as follows: L pomona, 12.47%; L icterohaemorrhagiae, 10.32%; L canicola, 3.22%; L grippotyphosa, 0.86%; and L hardjo, 0.43%. The...
Hallauer C.1. Equine infectious anemia (EIA) is an immunologically-medicated disease. Immune complexes formed in blood and tissues are responsible for most symptoms and lesions (anemia, splenomegaly, lymphadenopathy, glomerulonephritis, etc.). In addition, a state of cellular hypersensitivity of the delayed type is involved in the pathogenesis. 2. Periodical attacks of pyrexia and clinical illness in the presence of immunity are caused by antigenically-modified variants of virus. By means of immunosuppressive treatments similar relapses of fever associated with the appearance of new virus variants can be...
Harasawa R, Konishi S, Ogata M.This research study focuses on detecting the presence of antibodies against adenovirus in horses imported into Japan and it demonstrates that the majority of horses imported into Japan have displayed […]
Gleeson LJ, Studdert MJ.Intrauterine infection of pregnant mare with equine herpesvirus type 2 (EHV 2) did not result in foetal abortion, stillbirth or recognisable disease. Collection of uterine fluid by allantocentesis or amniocentesis 107 days after inoculation confirmed that intrauterine infection was established. EHV 2 was isolated from both allantoic and amniotic fluid separately collected at the time of elective Caesarean section 156 days after inoculation and virus neutralising antibody to EHV 2 was present in the foal's presuckle serum at birth. A very mild clinical disease, characterised by a scant, mucous ...
Shen DT, Crawford TB, Gorham JR, McGuire TC.Twelve chemicals and commercial disinfectants were tested for inactivation of equine infectious anemia virus. In the presence of 10% bovine serum, all chemicals inactivated 4 log10 (based on 0.1 ml) of the virus within 5 minutes at 23 C. A reduction of at least 4 log10 was observed when the virus was exposed for 1 minute to substituted phenolic disinfectants (3 commercial preparations and sodium orthophenylphenate), halogen derivatives (iodophor and sodium hypochlorite), chlorhexidine, and 70% ethanol. Sodium hydroxide (5%), 2% formalin, and 2% glutaraldehyde were slower to inactivate the viru...
Kucera CJ, Beckenhauer WH.An inactivated, aluminum hydroxide adjuvant equine influenza vaccine was tested in horses and guinea pigs to determine the levels of antigen that would elicit maximum serological responses. Vaccine containing serial twofold increments of A/Equi-1/Prague and A/Equi-2/Miami strains of equine influenza virus was administered to random groupings of both types of test animals. The hemagglutination inhibition antibody response for each group was then measured. Results in horses and guinea pigs were compared to determine if the equine serological values could be related to a potency test in laborator...
Moore RM, Moulthrop JI, Sather GE, Holmes CL, Parker RL.Field studies were conducted in 1972 to determine the immunization status of equines along the Mexico, Arizona, and New Mexico borders. Interviews with horse owners were conducted along roads selected at random in the counties of Santa Cruz and Yuma, Ariz., and in Dona Ana County, N. Mex. At least 450 horse owners in each county were asked about the vaccination status of their animals, and information was taken on 1,260 animals. Blood specimens were obtained from every third equine, regardless of stated vaccination status, and tested for the presence of Venezuelan equine encephalitis (VEE), we...
Potter ME, Currier RW, Pearson JE, Harris JC, Parker RL.In mid-July, 1975, western equine encephalomyelitis (WEE) virus was isolated from mosquitoes collected in flooded areas of eastern North Dakota and western Minnesota. Inasmuch as clinical manifestations of WEE are usually observed in horses before human cases of encephalitis are recognized, surveillance of equine disease was initiated. Sixty-one practicing veterinarians from the are under surveillance reported 281 cases of WEE in horses from June through September, with peak incidence in late July. The high percentage of sero-positive, clinically normal, unvaccinated horses in one region sugge...
Coggins L, Auchnie JA.Equine infectious anemia (EIA) has been enzootic in Hong Kong since the end of World War II. In 1972, a serologic survey of the horses at the Hong Kong Jockey Club indicated 23% prevalence of EIA. Disease control measures were instituted, and the spread of infection was reduced. In 1976, the prevalence of EIA was believed to be sufficiently low to implement procedures for eradication of EIA from all horses in Hong Kong. A correlation between EIA and poor performance of racehorses was demonstrated.
McMullan WC, Joyce JR, Hanselka DV, Heitmann JM.Amphotericin B was used systemically or locally, or both, in the treatment of localized subcutaneous phycomycosis in horses. In 8 of 10 cases, the results were satisfactory. Intravenous treatment was well tolerated at an average starting daily dosage of 0.38 mg/kg, increasing up to as high as 1.47 mg/kg. It was concluded that the ideal treatment regimen would include early surgical removal of the lesion followed by daily intravenous and topical administration of amphotericin B, with periodic extirpation of small necrotic tracts as necessary.
Teruya JM, Santa Rosa CA, Giorgi W, Yanaguita RM.A serological examination was carried out for L. monocytogenes antibodies on 9,318 domestic animal--7,809 bovine, 838 horses and 671 swine--in São Paulo, Brazil. Serum agglutination in tubes was the method used. Only somatic antigens from serotypes 1, 2, 3, 4a and 4b were employed. It was considered reagent all sera reacting in a titer 1/20 while as positive only sera with 1/320 or above. According this criteria the results showed showed that in cattle 17.8% were reagent but only 8 sera were positive for types 1, 2 and 4b. Only type 1 was found in horses in a rate of 22.7% reagent, and 11 pos...
Dubey JP, Streitel RH, Stromberg PC, Toussant MJ.Hearts, diaphragms, esophagi, and spinal cords from 266 horses were obtained at slaughter in Creston, Ohio. Tissues were examined microscopically for Sarcocystis in sections, digested in trypsin to obtain bradyzoites, and fed to 10 dogs and 10 cats. Intramuscular cysts were found in selections of two hearts from 57 horses and four esophagi from 107 horses. The cysts were up to 900 micron long and up to 70 micron wide. The cyst wall was 1 to 2 micron thick and cross-striated. The enclosed bradyzoites were banana-shaped, 15 to 20 by 20 to 3 micron, and contained several PAS-positive granules. Br...
Burrows R, Spooner PR, Goodridge D.Ponies held in isolation for 40 months were vaccinated and revaccinated with four commercial equine influenza vaccines. Little or no HI antibody was detected after the first inoculation; second and subsequent annual revaccinations produced peak HI antibody titres between 7 and 14 days. Titres fell quickly between 14 and 28 days and less quickly thereafter. The decline of HI antibody appeared to be related more to the initial titre attained and to the period after vaccination than to the composition of the vaccine. The response to a first annual revaccination was superior to that produced by a ...
Jeffcott LB, Rossdale PD.The current knowledge of the clinical signs, epidemiology and pathogenesis of abortion due to the equid herpesvirus (EHV 1) is reviewed. The relationship between the respiratory and abortigenic forms of the disease is discussed as well as the low incidence of virus abortion in the UK compared to some other parts of the world. Some practical aspects of the disease as they affect stud management are considered including methods of diagnosis, prophylaxis and the necessary action to be taken to prevent spread of infection.
Petzoldt K, Merkt H, Müller E, Kirpal G.Over the last years the percentage of foals lost by EHV at term or close to term seems to be higher than in former years. Furthermore, the pathological findings seem to shift from liver to lung. So far there has been no explanation for this phenomenon.