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.
Rogers HJ.Under a variety of conditions of concentration, Eh, and pH, horse anti- serum and normal horse serum exerted similar bacteriostatic effects against Type A. Ferric iron abolished the bacteriostatic effect when added during the first 2 hours of incubation at Eh+60 mV. Ferrous iron abolished the bacteriostatic effect when added after 3 hours. Ferric iron abolished the bacteriostatic effect at—140 mV. A mixture consisting of horse β- and γ-globulins together with human transferrin exerted a bacteriostatic effect similar to that of whole serum. This system responded in the same way as whole se...
Ozawa Y, Bahrami S.Formalized African horse-sickness (AHS) type 9 virus cultivated in monkey kidney stable (MS) cell cultures was experimentally used for immunizing horses. Inactivated vaccines prepared either from viscerotropic or neurotropic type 9 AHS virus produced antibodies in vaccinated horses. Immunity developed in all horses vaccinated with various amounts of the vaccine, and protected them from infection, when challenged 5 weeks after vaccination.
Geurden T, De Keersmaecker F, De Keersmaecker S, Claerebout E, Leathwick DM, Nielsen MK, Sauermann CW.In the present study, an anthelmintic treatment regimen with reduced treatment frequency was evaluated in horses on two study sites in Belgium during three consecutive summer pasture seasons. Historically, the horses on both study sites were treated up to 6 times a year with ivermectin (IVM) or up to 4 times a year with moxidectin (MOX), and previous efficacy evaluations indicated a reduced egg reappearance period in some of the treated horses for both IVM (28 days) and MOX (42 days). In the present study, all horses were treated with IVM or MOX in the spring and in autumn. Faecal egg counts (...
Ochi A, Sekiguchi M, Tsujimura K, Kinoshita T, Ueno T, Katayama Y.Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings. In both cases, significant gross lesions, restricted to the lungs, consisted of numerous firm and coalescing nodules widely distributed throughout the lung. The nodules were <3 cm in diameter and pale white to t...
Rutkowski M, Krzemińska-Fiedorowicz L, Khachatryan G, Kabacińska J, Tischner M, Suder A, Kulik K, Lenart-Boroń A.Frequent occurrence of microbial resistance to biocides makes it necessary to find alternative antimicrobial substances for modern veterinary medicine. The aim of this study was to obtain biodegradable silver nanoparticle-containing (AgNPs) foils synthesized using non-toxic chemicals and evaluation of their activity against bacterial pathogens isolated from oral cavities of cats, dogs and horses. Silver nanoparticle foils were synthesized using sodium alginate, and glucose, maltose and xylose were used as reducing agents. The sizes of AgNPs differed depending on the reducing agent used (xylose...
Slusarewicz P, Pagano S, Mills C, Popa G, Chow KM, Mendenhall M, Rodgers DW, Nielsen MK.Intestinal parasites are a concern in veterinary medicine worldwide and for human health in the developing world. Infections are identified by microscopic visualisation of parasite eggs in faeces, which is time-consuming, requires technical expertise and is impractical for use on-site. For these reasons, recommendations for parasite surveillance are not widely adopted and parasite control is based on administration of rote prophylactic treatments with anthelmintic drugs. This approach is known to promote anthelmintic resistance, so there is a pronounced need for a convenient egg counting assay...
Cutolo AA, Santos AT, Allegretti SM.Twenty horses naturally infected with nematodes were included in a blind, controlled field study on efficacy and safety of an oral 2% ivermectin formulation at a dose of 0.2 mg.kg(-1). Horses were divided into treated and non-treated (control) groups with ten animals each based on preliminary counts of eggs per gram of feces (EPG). Stool samples were collected after treatment for identification of nematode species. Clinical evaluations and EPG counts were performed on days 0, +5, +14 and +19. Nineteen nematode species were identified: Coronocyclus ulambajari, Craterostomum acuticaudatum, Cyath...
Onasanya AE, El-Hage C, Diaz-Méndez A, Vaz PK, Legione AR, Browning GF, Devlin JM, Hartley CA.Equid gammaherpesvirus 2 (EHV2) is a gammaherpesvirus with a widespread distribution in horse populations globally. Although its pathogenic significance can be unclear in most cases of infection, EHV2 infection can cause upper respiratory tract disease in foals. Co-infection of different strains of EHV2 in an individual horse is common. Small regions of the EHV2 genome have shown considerable genetic heterogeneity. This could suggest genomic recombination between different strains of EHV2, similar to the extensive recombination networks that have been demonstrated for some alphaherpesviruses. ...
Grønvold AM, L'Abée-Lund TM, Strand E, Sørum H, Yannarell AC, Mackie RI.Antimicrobial treatment is associated with the spread of antimicrobial resistance and disturbances in the ecological balance of intestinal microbiota. In horses, the main adverse effect of antimicrobial treatment is colitis. We used culture and 16S rRNA gene based molecular methods to monitor the prevalence of antimicrobial resistance and changes in predominant fecal populations during penicillin treatment and general anesthesia of horses in the clinical setting. After 5 days of parenteral administration of penicillin, fecal Escherichia coli were resistant to multiple unrelated antimicrobial a...
Wheat JD.The migration of strongyle larvae is the most common or basic underlying cause of colic in the horse. Disease conditions producing symptoms of colic occur in all sections of the intestinal tract and consist of impactions, torsions, herniations and foreign bodies. Colic also occurs as a result of pre- and post-partum diseases such as torsion of the uterus, haemorrhage, rupture and inversion of the uterus. In general, lesions resulting in circulatory obstruction are the types requiring surgical intervention. There are six general types of small intestine obstruction that lend themselves to surgi...
Morris DD, Messick J, Whitlock RH, Palmer J, Ward MV, Feldman BF.Hemostatic function was determined in 10 ponies at various times after inoculation with Ehrlichia risticii to determine whether equine ehrlichial colitis (EEC) caused changes in the hemostatic system and to determine the prognostic value of hemostatic function tests during EEC. Mean platelet count; plasma fibrinogen, fibronectin, factor VIII: coagulant, alpha 2-antiplasmin, and plasminogen values; and serum concentrations of fibrin/fibrinogen degradation products changed significantly (P less than 0.05) from base line (day 0, before inoculation) during 18 days after inoculation with E risticii...
McGurrin MK, Vengust M, Arroyo LG, Baird JD.An outbreak of protein-losing enteropathy associated with Lawsonia intracelluaris infection was diagnosed in 6 standardbred foals from a farm in Ontario. Wildlife exposure may have been involved in the perpetuation of disease in this outbreak. The clinical presentation, treatment, outcomes, and pathological findings are described. Éclosion d’infections à Lawsonia intracellularis dans un troupeau de Standardbred en Ontario. Une éclosion d’entéropathies exsudatives associée à une infection à Lawsonia intracellularis a été diagnostiquée chez 6 poulains Standardbred d’une ferme de ...
Kern A, Perreten V.To determine the antibiotic resistance and fingerprint profiles of methicillin-resistant coagulase-negative staphylococci (MRCoNS) from animal infections among different practices and examine the history of antibiotic treatment. Methods: Isolates were identified by mass spectrometry and tested for antimicrobial resistance by broth dilution, microarrays and sequence analysis of the topoisomerases. Diversity was assessed by PFGE, icaA PCR and staphylococcal cassette chromosome mec (SCCmec), arginine catabolic mobile element (ACME) and multilocus sequence typing. Clinical records were examined re...
Pasing SS, Aurich C, von Lewinski M, Wulf M, Krüger M, Aurich JE.An important factor influencing stallion fertility is the microbial contamination of semen. Aims of this study were to investigate changes in the microbiological population of the genital mucosa and semen in artificial insemination stallions (n=16) from before to after one breeding season (February-August). MALDI-TOF-MS (matrix assisted laser desorption/ionization time-of-flight mass spectrometry) was used for identification of microbial agents. For bacteriology, swabs from the urethral opening, urethral fossa and penile sheath as well as semen were collected at 4-week-intervals. For semen mot...
Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL, Garber LP, Kopral CA, Phillippi-Taylor AM, Traub-Dargatz JL.Equine strongyle parasites are ubiquitous in grazing equids across the world. Anthelmintic resistance is widely developed in cyathostomin populations, but very few surveys have evaluated anthelmintic efficacy in equine populations in the United States, and most of these are over 15 years old. The present study was carried out as part of the National Animal Health Monitoring Systems (NAHMS) Equine 2015-2016 study. The aims were to investigate anthelmintic treatment efficacy by means of the fecal egg count reduction test (FECRT) and identify parameters associated with decreased efficacy. Data we...
Mirajkar NS, Kelley MR, Gebhart CJ.Reported herein is the draft genome sequence of equine-origin Lawsonia intracellularis strain E40504, an obligate intracellular bacterium and the etiological agent of equine proliferative enteropathy. The 1.69-Mb draft genome sequence includes 1,380 protein-coding genes and 49 RNA genes, and it lacks a genomic island reported in swine-origin L. intracellularis strain PHE/MN1-00.
Fodor L, Szenci O, Peters M, Varga J, Szemerédi G, Wyszoczky F.A total of seven Bacteroides ureolyticus strains were isolated from the cervix and the clitoral fossa of mares with vaginal discharge. No other bacteria capable of causing metritis or vaginitis were isolated from the samples. The isolated strains resembled Taylorella equigenitalis. Both species are catalase, oxidase and alkaline phosphatase positive, but, in addition to these characteristics, B. ureolyticus strains produced urease and they could not tolerate 10% O2. They also failed to be agglutinated in a hyperimmune serum raised against T. equigenitalis; however, B. ureolyticus and T. equige...
Vincze B, Varga M, Kutasi O, Zenke P, Szenci O, Baska F, Bartels A, Spisák S, Cseh S, Solymosi N.Equine grass sickness (also known as dysautonomia) is a life-threatening polyneuropathic disease affecting horses with approx. 80% mortality. Since its first description over a century ago, several factors, such as the phenotype, intestinal microbiome, environment, management and climate, have been supposed to be associated with the increased risk of dysautonomia. In this retrospective study, we examined the possible involvement of genetic factors. Medical and pedigree datasets regarding 1,233 horses with 49 affected animals born during a 23-year period were used in the analysis. Among the des...
Varadin M.Infertility, resulting from failure to conceive during the preceding breeding season, was caused by various forms of endometritis in forty-four mares of Highland and Arabian breeds in Yugoslavia. Chronic mucopurulent and latent catarrhal endometritis occurred most frequently. Douching of the uterus on alternate days for 9 days with warm and cold sterile salt solutions (ranging from 7% to 1% w/v) in the early autumn resulted in conception in 47-7% of mares at an average of 15-2 days after the onset of treatment, and another 36-7% becoming pregnant in the following spring. Mating at the wrong st...
Koenig JB, Rodriguez A, Colquhoun JK, Stämpfli H.During exploratory laparotomy of a foal with colic, a congenital abnormally developed large colon was identified incidentally. Long-term follow-up showed that the colt was more prone to gas-colic with diet and exercise changes than were other horses, due possibly to the short colon. Malformation congénitale du côlon (côlon court) chez un poulain Standardbred âgé de 4 mois. Au cours d’une laparotomie exploratrice chez un poulain atteint de colique, une malformation congénitale du gros côlon a été identifiée de façon fortuite. Un suivi à long terme a montré que le poulain était d...
Magnarelli LA, Ijdo JW, Van Andel AE, Wu C, Oliver JH, Fikrig E.To test serum samples of dogs and horses by use of class-specific recombinant-based ELISA for establishing a diagnosis of granulocytic ehrlichiosis attributable to infection with organisms from the Ehrlichia phagocytophila genogroup. Methods: Serum samples from 43 client-owned dogs and 131 horses (81 with signs of acute illness and 50 without signs of disease). Methods: Serum samples were analyzed, using ELISA with a recombinant 44-kd protein antigen for IgM and IgG antibodies to the human granulocytic ehrlichiosis (HGE) agent (NCH-1 strain). Western blot analyses, using infected human promyel...
Lord J, Carter C, Smith J, Locke S, Phillips E, Odoi A.Surveillance of antimicrobial resistance (AMR) among veterinary pathogens is necessary to identify clinically relevant patterns of AMR and to inform antimicrobial use practices. Streptococcus equi subsp. zooepidemicus and Rhodococcus equi are bacterial pathogens of major clinical importance in horses and are frequently implicated in respiratory tract infections. The objectives of this study were to describe antimicrobial resistance patterns and identify predictors of AMR and multidrug resistance (MDR) (resistance to three or more antimicrobial classes) among equine S. zooepidemicus and R. equi...
Lannergård J, Frykberg L, Guss B.Streptococcus equi subspecies equi is an important horse pathogenic bacterium causing a serious disease called strangles. Using bioinformatics we identified a gene denoted cne (gene encoding collagen-binding protein from S. equi) coding for a novel potential virulence factor of this species called protein CNE. The protein is composed of 657 amino acids and has the typical features found in cell surface-anchored proteins in Gram-positive bacteria. CNE displays amino acid sequence similarities to the previously well-studied collagen-binding protein CNA from Staphylococcus aureus, a proven virule...
Bingham AM, Burkett-Cadena ND, Hassan HK, McClure CJ, Unnasch TR.Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian- and reptile-derived meals observed in the summer. Four ...
Scare JA, Dini P, Norris JK, Steuer AE, Scoggin K, Gravatte HS, Howe DK, Slusarewicz P, Nielsen MK.Ascarid parasites infect a variety of hosts and regular anthelmintic treatment is recommended for all species. Parascaris spp. is the only ascarid species with widespread anthelmintic resistance, which allows for the study of resistance mechanisms. The purpose of this study was to establish an in vitro drug exposure protocol for adult anthelmintic-naïve Parascaris spp. and report a preliminary transcriptomic analysis in response to drug exposure. Live worms were harvested from foal necropsies and maintained in RPMI-1640 at 37 °C. Serial dilutions of oxibendazole (OBZ) and ivermectin (IVM) we...
Lin Y, Barker E, Kislow J, Kaldhone P, Stemper ME, Pantrangi M, Moore FM, Hall M, Fritsche TR, Novicki T, Foley SL, Shukla SK.Not much is known about the zoonotic transmission of methicillin-resistant Staphylococcus aureus (MRSA) in companion animals in the United States. We report the rate of prevalence of S. aureus and MRSA recovered from clinical samples of animals requiring treatment at veterinary clinics throughout the upper midwestern and northeastern United States. Methods: We compared phenotypes, genotypes, and virulence profiles of the MRSA isolates identified in companion animals, such as cats, dogs, horses, and pigs, with typical human nosocomial and community-associated MRSA (CA-MRSA) genotypes to assess ...
Thompson NE, Bergdoll MS, Pattee PA.The factor in normal sera primarily responsible for the enhancement of transfection (and transformation) of Staphylococcus aureus was identified as fibronectin. Serum samples which were depleted of fibronectin by affinity chromatography showed a marked decrease in enhancing activity. Fibronectin isolated from sera of several animal species demonstrated enhancing activity.
Kraouchi DE, Meradi S, Bentounsi B.The composition, prevalence, and seasonal dynamic of species were studied at the slaughterhouse of Constantine region (East Algeria) in 128 horses over an 18 months period. Our survey revealed that 124 (96.9%) horses were infected with a mean intensity of 161 larvae of spp. Four species of were identified; and were by far the predominant species with 95.3% and 77.3% respectively, followed by (14.0%) and (10.1%). The age, sex, and breed of horses did not affect the distribution of the infection. Second-stage larvae (L2) of were absent between April and July and present in higher numbers...
van Dinten LC, van Tol H, Gorbalenya AE, Snijder EJ.Equine arteritis virus (EAV), the prototype Arterivirus, is a positive-stranded RNA virus that expresses its replicase in the form of two large polyproteins of 1,727 and 3,175 amino acids. The functional replicase subunits (nonstructural proteins), which drive EAV genome replication and subgenomic mRNA transcription, are generated by extensive proteolytic processing. Subgenomic mRNA transcription involves an unusual discontinuous step and generates the mRNAs for structural protein expression. Previously, the phenotype of mutant EAV030F, which carries a single replicase point mutation (Ser-2429...
Tatarov G, Dilovski M.An avirulent immunogenic virus strain mutant of the causative agent of rhinopneumonia was found to cause abortions and respiratory diseases in horses. The mutant was obtained with the use of a virulent strain that induced strongly manifested clinical symptoms of the disease, and was cultured in cell media containing 5-iodine-2-desoxiuridine as an antimetabolite, following a definite pattern. It was found that the mutant completely lost its virulence, however, it retained its immunogenicity. It likewise retained these newly acquired biologic properties with regard to its being stable and irreve...
Tamamura-Andoh Y, Niwa H, Kinoshita Y, Uchida-Fujii E, Arai N, Watanabe-Yanai A, Iwata T, Akiba M, Kusumoto M.Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have become a cause for great concern. Although some studies have reported the prevalence of ESBL-producing bacteria and ESBL-encoding genes in horses worldwide, the genetic structure surrounding the ESBL gene has not been analysed in detail. In the present study, we isolated two ESBL-producing Escherichia coli strains from diseased racehorses in Japan and demonstrated the mechanisms underlying the acquisition of their antimicrobial resistance (AMR) genes. Two ESBL-producing E. coli strains (E148 and E189) were isolated from th...
Hedegaard CJ, Heegaard PM.Immunisation by administration of antibodies (immunoglobulins) has been known for more than one hundred years as a very efficient means of obtaining immediate, short-lived protection against infection and/or against the disease-causing effects of toxins from microbial pathogens and from other sources. Thus, due to its rapid action, passive immunisation is often used to treat disease caused by infection and/or toxin exposure. However immunoglobulins may also be administered prior to exposure to infection and/or toxin, although they will not provide long-lasting protection as is seen with active...
