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.
Sponseller ML, Binn LN, Wooding WL, Yager RH.Four field strains of western encephalitis virus were inoculated subcutaneously or intracranially (i/c) into recently weaned ponies. After s/c inoculation, 3 of the 4 strains produced an inapparent infection with a short period of viraemia. The 4th strain produced viraemia, fever, and signs of central nervous system disease. Viraemia occurred after intracranial inoculation with each strain; however, a variation in clinical response occurred, ranging from an inapparent infection to death. The disease pattern was characterized by three successive phases: viraemia, increased body temperature, and...
Darlington RW, James C.Darlington, R. W. (St. Jude Children's Research Hospital, Memphis, Tenn.), and C. James. Biological and morphological aspects of the growth of equine abortion virus. J. Bacteriol. 92:250-257. 1966.-The growth of equine abortion virus (EAV) was studied by bioassay and electron microscopy in L-cell monolayer and suspension cultures, and in HeLa and BHK 21/13 cell monolayers. Results of virus assay (plaque-forming units) indicated that production of cell-associated virus (CAV) began at 6 to 9 hr after infection in all of the cell strains used. Virus release occurred 1 to 2 hr later. By 15 to 20 h...
Rosser EJ.Although there are numerous dermatoses in the horse in which the formation of crusts occurs, there are two relatively common and important infectious crusting dermatoses, namely, dermatophytosis and dermatophilosis. This article reviews the current concepts regarding the etiology and pathogenesis of each disease, as well as the more common clinical presentations, methods of diagnosis, and treatment.
Thirumalapura NR, Livengood J, Beeby J, Wang W, Goodrich EL, Goodman LB, Erol E, Tewari D.Neorickettsia risticii, an obligate intracellular bacterium, is the causative agent of Potomac horse fever (PHF). Diagnosis of PHF is based on demonstration of serum antibodies, isolation of N. risticii, and/or detection of nucleic acid by a PCR assay. An existing real-time PCR assay targeting the N. risticii 16S rRNA has been validated using blood samples from horses with colitis, and snails; to our knowledge, the performance of the assay for other sample types has not been reported. We describe here a modification of the 16S rRNA gene assay by the addition of a set of primers and probe targe...
Nagatomo H, Tokita Y, Shimizu T.Although it is known that commercialized bovine serum is sometimes contaminated with mycoplasmas, it is not clear whether mycoplasmas can survive in horse serum. In this study, as a preliminary examination of the survival of mycoplasmas inoculated in horse sera, the survivability of 8 strains of 7 mycoplasmas was tested. The results obtained reveal that two strains of M. bovis and M. gallisepticum were found to survive in non-heated and inactivated sera for 94 to 330 days at 30 or 37 degrees C. Three strains of M. bovirhinis, M. gateae and A. laidlawii lived for 7 to 330 days depending upon th...
Harasawa R, Higashi T.Viral DNA obtained from the equine adenovirus propagated in equine transitional cell carcinoma (ETCC) cells and in equine fetal dermis cells were compared by cleaving with isoschizomeric restriction enzymes, HpaII and MspI, and then electrophoresed in 1.4 per cent agarose gels. Differences between the HpaII and MspI cleavage patterns were evident in viral DNA obtained only from the equine adenovirus propagated in ETCC cells, suggesting site specific methylation at CpG sequences.
Anderson WI, King JM, Rothwell JT.Segmental atresia of the transverse colon was observed at necropsy in a neonatal foal. The dorsal and ventral components of the large colon were fused, and ended blindly. The small colon was collapsed and completely closed at its cranial end. The right and left dorsal and ventral colons were fused into one blind-ended tube. Histologically, eosinophilic intranuclear inclusion bodies demonstrative of Equine Rhinopneumonitis were present in the thymus.
Current and emerging issues: reminder of the notifiable status of porcine epidemic diarrhoeaHighlights from the scanning surveillance networkUpdate on international disease threatsReview of animal health threats by the Veterinary Risk Group These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for July 2017.
Franken P, van den Hoven R, Sasse HH, Koeman JP, Goedegebuure SD.The case of a three-year-old mare is reported, in which clinical examination revealed the presence of haemorrhagic diathesis as a result of disseminated intravascular coagulation. The animal also showed severe lameness which was due to involvement of the long bones. The diagnosis was only established after death.
Iqbal J, Edington N.Equid herpesvirus 1 (EHV-1) is the most common cause of virus-induced abortion in horses. After primary infection the virus becomes latent predominantly in the respiratory tract lymph nodes and the genome can also be detected in the peripheral nervous system. The role of mouse as a feasible model for the establishment of latency and reactivation of EHV-1 was investigated. Intracerebral and intranasal infections of 3- and 17-day-old mice were made and virus replication was confirmed by virus isolation and detected by indirect immunofluorescence (IIF) in brain. For reactivation studies, the mice...
Russo AM, Ebermayer SE, Mancebo OA, Monzón CM.The fungus Curvularia verruculosa, which produces eumycotic mycetomas, was isolated from skin of horses with granulomatous lesions on the legs. The isolation was made in Sabouraud dextrose agar medium. The horses came from Comandante Fontana suburb, Formosa-Argentina. This finding would be the first report of Curvularia in horses in Argentina.
Ghaly P, Di Mascio D, Vicaretti M.A common source of infection in equine, , is an uncommon pathogen in humans, rarely identified as the cause for mycotic aortic aneurysms. Typically associated with consumption of unpasteurized milk or contact with horses, can result in severe bacteremia, endocarditis and meningitis. We describe the presentation and successful management of a 69-year-old retired equestrian who underwent infrarenal aortic resection and reconstruction using autologous right femoral vein for a mycotic aneurysm.
Day FT, Crowhurst RC, Simpson DJ, Greenwood RE, Ellis DR, Eaton-Evans W.An outbreak of contagious equine metritis occurred in Newmarket in 1977. This survey records the effect on fertility of 20 of the stallions which were infected. Swabbing of mares since then has detected 37 carrier mares harbouring the organism, most frequently in the clitoral area. This swabbing programme reduced the incidence of new cases in 1978 to 3 mares and 1 stallion.
Nijdam P, Elmas C, Fugazzola MC.A 1-month-old Miniature Shetland colt was presented to the Burg Müggenhausen Equine Clinic. Primary complaints were regurgitation of milk, bilateral white nasal discharge, and weakness. Physical examination, endoscopy of the esophagus, and contrast radiography led to the diagnosis of an esophageal stricture and aspiration pneumonia. Surgical treatment by means of an esophagomyotomy was performed. The foal improved only temporarily and multiple sessions of endoscopic balloon dilation of the esophagus were performed afterwards. 12 months after the final treatment the foal was healthy and had no...
Hara Y, Nakajima T, Akamatsu M, Yahiro M, Kagawa S, Petry S, Matsuda M, Moore JE.Contagious equine metritis is a bacterial infectious disease of horses caused by Taylorella equigenitalis, a Gram-negative eubacterium. The disease has been described in several continents, including Europe, North America and Asia. A novel molecular method was developed to detect clustered regularly interspaced short palindromic repeats (CRISPRs), which were separated by non-repetitive unique spacer regions (NRUSRs) of similar length, in the Taylorella equigenitalis EQ59 strain using a primer pair, f-/r-TeCRISPR-ladder, by PCR amplification. In total, 31 Taylorella isolates (17 T. equigenitali...
Singh G.A/eq-1 and A/eq-2 influenza viruses were isolated simultaneously from an epidemic of equine influenza in north India. Evidently, both types of equine influenza viruses circulated in the equine population at the same time.
Adeyefa CA, Durojaiye OA.Serum samples obtained from 107 Polo horses showing clinical signs of viral respiratory disease were tested for precipitating antibodies to adenovirus by agar gel precipitation test and counter-immunoelectrophoresis method. The results obtained demonstrate serological evidence of adenovirus infection in Polo horses in Nigeria. The counter-immunoelectrophoresis method was observed to be about 3 times more sensitive than the agar gel precipitation test with 19.3 vs 64.5%. It could thus be used to screen a large number of serum samples within a short period.
Gallen F, Kernaonet E, Foulet A, Goldstein A, Lebon P, Babinet F.Rhodococcus Equi, a strictly aerobic Gram positive coco-bacillus, is a pathogen for horses and foals. It may induce opportunistic infections and is described in AIDS infected patients. We report the case of a 47-year old man, breeder of horses, with kidney transplant who has presented, 8 years after his graft, an impairment of health, a fever and evidence of pulmonary disease. The pulmonary biopsy under scanner guidance and microbiology study, has displayed the diagnosis of Rhodococcus equi infection. The evolution has been favorable with double antibiotherapy (follow-up 27 months). Ten compar...
Moorthy AR, Spradbrow PB.Mycoplasmas were isolated from two of 43 nasal swabs taken from live horses, and from one of 28 tracheal swabs taken from slaughtered horses. The slaughtered horse that yielded mycoplasmas had no gross pathological changes in the respiratory tract, but the nasal isolations were made from horses with rhinitis. The three mycoplasmas could be distinguished by cultural characteristics, and probably they represent three different species.
DiPietro JA, Lock TF, Todd KS, Davis JL.Eighteen pony foals inoculated with 1,500 +/- 109 infective Parascaris equorum eggs were given 0.02 ml of ivermectin vehicle (liquid)/kg of body weight, PO, (control); 0.2 mg of ivermectin paste/kg, PO; or 0.2 mg ivermectin liquid/kg, PO, on postinoculation day (PID) 28. Foals were euthanatized on PID 42, and the small intestinal contents were examined for P equorum larvae. The mean number of fourth-stage P equorum larvae in foals treated with ivermectin paste and liquid were 3.5 and 6, respectively. Significantly (P less than 0.01) higher mean numbers of larvae (1,250) were detected in foals ...
Gummow B, Herr S, Brett OL.A complement fixation test, using round-bottomed microtitration plates and an 8 channel microdiluter, based on that used for brucellosis by Herr, Huchzermeyer, Te Brugge, Williamson, Roos & Schiele, 1985, has been developed for use on the sera of horses to detect antibodies to the contagious equine metritis organism. The results with 2 known positive sera tested 116 times in 27 separate tests were reproducible for the most part within a twofold range. They seldom exceeded these limits and never exceeded a fourfold range. The test itself is capable of being carried out within 90 min. The test w...
Sanada Y, Noda H, Nagahata H.The blastogenic response of lymphocytes from 16 newborn foals naturally infected with Rhodococcus equi was investigated, in order to evaluate the relationship between R. equi infection and depressed host response. Naturally infected foals showed evidence of R. equi infection at 5-6 weeks of age, as determined by clinical, haematological, bacteriological and serological methods. The blastogenic response of lymphocytes against phytohaemagglutinin was significantly depressed (stimulation index < 1.80; P < 0.01, P < 0.05) in R. equi-infected foals at 5-6 weeks of age compared with those o...
Casola C, Pot SA, Lavaud A, Voelter K.Corneal cross-linking should be considered as treatment option in Friesian horses with infectious keratitis and corneal dystrophy. Optical coherence tomography, giving information of corneal structure, can help for diagnosis and monitoring.
Spoormakers TJ, IJzer J, Sloet van Oldruitenborgh-Oosterbaan MM.A 22-year-old Dutch Warmblood mare was referred to Utrecht University with progressive left hind limb paresis and hyporeflexia. The preliminary clinical diagnosis was the neurological form of equine herpes virus (EHV-1) infection. Within 1 day of admission, the mare became recumbent and deteriorated rapidly. Postmortem examination revealed an adenocarcinoma of the caecum, with metastases in all regional lymph nodes and extending from the lumbar nodes into the vertebral canal, causing spinal cord compression and destruction of the left 4th and 5th lumbar nerves.
Schoster A, Anderson ME.A 9-year-old Quarter horse was presented for chronic refractory pneumonia. On necropsy, an hepatic abscess, caudal vena cava thrombosis, pulmonary thromboembolism, and embolic pneumonia were identified. Similar lesions have been reported in cattle as caudal vena cava thrombosis syndrome, however this syndrome has not previously been reported in horses. Un cheval Quarter horse âgé de 9 ans est présenté pour une pneumonie réfractaire chronique. À la nécropsie, un abcès hépatique, une thrombose de la veine cave caudale, un thromboembolisme pulmonaire et une pneumonie embolique ont été...
Oge S, Oge H, Yildirim A, Kircali F.Necropsies on 43 horses, 35 donkeys and two mules slaughtered in Ankara, Turkey, revealed that 12 (15%) of the equines harboured adult Setaria equina. When blood samples were checked for microfilariae, using Knott's method and a combination of membrane filtration followed by histochemical staining for acid phosphatase (AP), only three (4%) of the animals were found to be microfilaraemic. When stained for AP, the S. equina microfilariae exhibited diffuse red staining over the entire body, including the sheath, with brighter staining around the anal and excretory pores. Application of Knott's me...
West Nile virus in Europe and the USA. Evidence that the spread of vesicular stomatitis in the USA is beginning to slow. Summary of UK surveillance testing, July to September 2015 These are among matters discussed in the most recent quarterly equine disease surveillance report, prepared by Defra, the Animal Health Trust and the British Equine Veterinary Association.
Weiblen R, Rabuske M, Rebelatto MC, Nobre VM, Canabarro TF.We report an outbreak of abortion due to equine herpesvirus (EHV) in 5 mares between 9 and 11 months of gestation, from a herd of 22 Thoroughbred mares. Equine herpesvirus was isolated from extracts of the liver, spleen and thymus but not from the lungs of a 9-month fetus grown in Rabbit Kidney (RK13) cells. The virus was identified by electron microscopy, where virus particles could be seen in the nucleus of infected cells, and by the fluorescent antibody technique with polyclonal antibodies against the whole virus. Anamnesis, necropsy, histopathology, bacteriology, and virology data suggest ...
Metz GE, Serena MS, Ocampos GM, Panei CJ, Fernandez VL, Echeverría MG.Equine arteritis virus (EAV) was isolated from a testicle of the presumable first stallion infected with EAV in Argentina. This virus isolate (named LT-LP-ARG) was confirmed by GP5-specific PCR and indirect immunofluorescence assays. The PCR product was sequenced, and the phylogenetic analysis revealed that the LT-LP-ARG strain of EAV forms a monophyletic group, together with other strains previously isolated in our laboratory (LP02 group). However, all Argentinean EAV strains belong to a polyphyletic group. We believe that the virus isolate presented in this report could be the origin of EAV ...
Menassé I.After a brief reference to the importance of the non-parenteral route of vaccination of domestic animals in general, the author deals, for each animal species separately, with the most important vaccines utilised by this method of administration. On the basis of bibliographical data, he describes the history of this use, discusses the results of the application in the field and draws the relative conclusions.
Paskin R.The equine influenza outbreak detected in August 2007 in New South Wales and Queensland did not enter Victoria, which was, however, considered at risk because of its sizable border with New South Wales. Accordingly, Victoria implemented a response plan to prevent disease entry and enable early detection of any disease. Horse movement restrictions, surveillance strategies and public awareness formed a large part of this response.
Lopes CA, Moreno G, Curi PR.The susceptibilities of 760 Staphylococcus aureus strains isolated from animal infections (400), human infections (300) and healthy human carriers (60) to seven antibiotics were determined by an agar dilution technique. The isolates from human infections were more resistant to a wider spectrum of antibiotics than were the strains from animal infections and healthy human carriers. Amikacin and gentamicin were the most active drugs against all groups of strains.
