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.
Bosch G, van Duijkeren E, Bergwerff AA, Rijkenhuizen AB, Ensink JM.Ceftiofur concentrations in an infected and uninfected environment were compared and the efficacy of locally administered ceftiofur was evaluated in an experimental infection with Staphylococcus aureus in tissue cages. Eight ponies had tissue cages (TCs) implanted s.c. on each side of the neck. Into one of the cages 150 mg of ceftiofur was administered and fluid samples were taken to determine ceftiofur concentrations. After 1 week the other TC was infected with S. aureus and subsequently treated with 150 mg ceftiofur administered locally into the TC once daily for 21 days. Samples of fluid we...
Hodgkinson JE.The future implementation of improved and sustainable control strategies for the major equine parasites will be dependent on a greater insight into their basic biology, pathogenicity and epidemiology together with an enhanced ability for accurate diagnosis. This paper will provide a review of the current molecular methods under development for the detection of equine parasites and their application to current scientific questions. In particular, the strongyles are recognised as important pathogens of horses and recent advances made in the study of this parasitic group at the single species lev...
Coles GC, Jackson F, Pomroy WE, Prichard RK, von Samson-Himmelstjerna G, Silvestre A, Taylor MA, Vercruysse J.Before revised World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines on the detection of anthelmintic resistance can be produced, validation of modified and new methods is required in laboratories in different parts of the world. There is a great need for improved methods of detection of anthelmintic resistance particularly for the detection of macrocyclic lactone resistance and for the detection of resistant nematodes in cattle. Therefore, revised and new methods are provided here for the detection of anthelmintic resistance in nematodes of ruminants, horses and ...
van der Meulen K, Caij B, Pensaert M, Nauwynck H.In vitro studies demonstrated that most equine herpesvirus 1 (EHV-1)-infected peripheral blood mononuclear cells (PBMC) do not expose viral envelope proteins on their surface. This protects them against antibody-dependent lysis. We examined whether viral envelope proteins are also undetectable on infected PBMC during cell-associated viremia. Further, surface expression of major histocompatibility complex (MHC)-I was examined, since MHC-I assists in making infected cells recognizable for cytotoxic T-lymphocytes (CTL). Four ponies, previously exposed to EHV, and two ponies that had no contact wi...
Wuersch K, Huessy D, Koch C, Oevermann A.Proliferative enteropathy (PE) caused by the obligate intracellular bacterium Lawsonia intracellularis is a disease of high economic impact in swine worldwide. In most other species the disease occurs as a sporadic infection. This paper reports a PE caused by L. intracellularis in a 9-month-old Pura Raza Española filly with a history of profuse diarrhoea. Pathological lesions consisted of a severe proliferative enteritis associated with argyrophilic bacteria in the apical cytoplasm of proliferating crypt epithelium. Characteristic PCR products confirmed the presumptive diagnosis of L. intrace...
Baselgia S, Doherr MG, Mellor P, Torsteinsdottir S, Jermann T, Zurbriggen A, Jungi T, Marti E.Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis caused by bites of Culicoides and Simulium species, and improved means of diagnosis are required. Objective: The cellular antigen simulation test (CAST) with C. nubeculosus and S. vittatum extracts was assessed in a population of IBH-affected and healthy horses. Variations in test results over a one year period and possible cross-reactivity between different insect extracts was studied. Methods: A total of 314 mature horses were studied using the CAST. Influence of severity of clinical signs, gender and age were evaluate...
Grønbaek LM, Angen O, Vigre H, Olsen SN.Streptococcus equi is the cause of strangles in horses. To improve diagnostic sensitivity, development and evaluation of DNA-based methods are necessary. Objective: To evaluate diagnostic methods and observe the pattern of bacterial shedding during natural outbreaks. Methods: Two herds with natural outbreaks of strangles were visited over a period of 15 weeks and 323 samples originating from 35 horses investigated. The diagnostic use of a nested PCR test was evaluated using a collection of 165 isolates of Lancefield group C streptococci (species specificity) and swabs from nasal passages or fr...
Zouiten H, Berrag B, Oukessou M, Sadak A, Cabaret J.Sport and leisure horses in Morocco are treated with several anthelmintics, organophosphates (dichlorvos), benzimidazoles (mostly thiabendazole) or tetrahydropyrimidines (mostly pyrantel pamoate) against nematodes. We studied three horse stables in Rabat, one in Meknes and one in Bouznika. Two of the Rabat and Bouznika stables had introduced a large number of horses from countries (Argentina or Europe) where resistance to benzimidazoles is frequent, whereas the Meknes stud farm remained without foreign introduction. The number of treatments was not very frequent (twice a year in adult horses) ...
Butler CM, Houwers DJ, Jongejan F, van der Kolk JH.This review discusses the literature on B. burgdorferi infections in view of the rising incidence of this infection in general and the increasing concerns of horse owners and equine practitioners. Lyme disease, the clinical expression of Borrelia infections in man is an important health problem. The geographic distribution of B. burgdorferi infections in equidae should resemble that of human cases because the vector tick involved, Ixodes ricinus, feeds on both species and, indeed, the infection has been established many times in horses. However, a definite diagnosis of the disease "Lyme borrel...
da Silva Anjos DH, de Lurdes A Rodrigues M.Nematodes from the ventral colon of 31 adult horses, 24 males and 9 females, in the metropolitan region of the state of Rio de Janeiro were analysed. There were 53,444 (86.4%) adults of the total recovered strongylid nematodes. They belonged to 21 species of Cyathostominae and seven of Strongylinae. Larval forms made up 13.6% (8407) of the total recovered, and 49% of the strongylid nematodes were observed in ventral colon. The most prevalent and abundant species were Cyathostomum tetracanthum, Cylicocyclus nassatus, Cylicostephanus minutus, Cylicostephanus longibursatus, Cylicostephanus leptos...
Weese JS, Caldwell F, Willey BM, Kreiswirth BN, McGeer A, Rousseau J, Low DE.There are increasing reports of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization in horses and evidence that MRSA can be transmitted between horses and humans. The objective of this study was to investigate reports of skin infection in personnel working with a foal with community-associated MRSA colonization and subsequent infection. Clinical diagnostic specimens were collected from individuals reporting skin lesions following contact with the affected foal. Nasal and groin screening swabs were collected from other veterinary personnel that attended a voluntary scr...
Apprich V, Spergser J, Rosengarten R, Stanek C.Keratinolytic properties of two dermatophytes (Microsporum gypseum, Trichophyton mentagrophytes) and three moulds (Scopulariopsis brevicaulis, Alternaria alternata, Geotrichum candidum) isolated from diseased equine hooves were examined to improve the understanding of pathogenic mechanisms leading to equine onychomycosis. Equine hoof horn material and skin, as well as hoof keratin and dermal keratin extracted from corresponding tissues, were used as sole carbon and nitrogen sources in five test tubes for each fungus. Within 18 days, supernatants of all tubes were repeatedly examined for kerati...
Gupta AK, Kaur D, Rattan B, Yadav MP.Three abortigenic Indian isolates of equine herpesvirus-1 (EHV-1) (Tohana, Hisar and Bikaner), along with two exotic abortigenic isolates (AB4 and V592) and another EHV-1 isolate (Jind) obtained from a case of perinatal foal mortality, were studied for variability. For this purpose, PCR and restriction endonuclease (RE) digestion techniques were used simultaneously as a DNA fingerprinting system. Nine different regions of EHV-1 virus were amplified by PCR using primer pairs specific for the regions and the products obtained from these regions were subsequently subjected to various restriction ...
Butler CM, van Gils JA, van der Kolk JH.Piroplasmosis, a disease endemic to most tropical and subtropical areas, appears to be spreading to more temperate zones. This article gives a review of equine piroplasmosis and describes an acute case of infection with Babesia caballi in a Dutch Standard bred foal after a short stay at a stud in Normandy (France). A 3-month-old stallion foal was presented with lethargy, fever of 41 degrees C, and pale mucosal membranes. Haematology revealed a low packed cell volume (14 l/l) leucytosis (25 G/l) and a high blood urea nitrogen concentration (20.1mmol/l). Infection with B. caballi was diagnosed o...
Duijkeren EV, Box AT, Schellen P, Houwers DJ, Fluit AC.Integrons in gentamicin- and cotrimoxazole-resistant Enterobacteriaceae from dogs and horses with clinical infections were analyzed by conserved segment PCR-RFLP. Five distinct integron types were found, most of which have previously been reported in Enterobacteriaceae isolated from humans and farm animals, indicating that resistance genes are exchanged between the reservoirs in humans, farm animals, and companion animals.
Valentine BA.A retrospective study examined data on cutaneous nodular and proliferative lesions in horses, donkeys and mules submitted to the Veterinary Diagnostic Laboratory at Oregon State University in a 3.5-year period. One hundred and sixteen non-neoplastic nodular and proliferative lesions were identified, comprising 18% of all lesions studied and 6.4% of total equine pathology accessions. Exuberant granulation tissue, eosinophilic granuloma, fungal granuloma, cysts and habronaemiasis were most common, and constituted 91% of non-neoplastic lesions, 16% of all lesions studied, and 5.85% of total equin...
Dunkel B, Palmer JE, Olson KN, Boston RC, Wilkins PA.Foals may present to a referral hospital with the primary diagnosis of uroperitoneum (UP), or they may develop UP while hospitalized for other reasons. Historical, physical, laboratory, and diagnostic variables of foals presenting with UP were compared to those developing UP while hospitalized. Emphasis was placed on the presence of electrolyte abnormalities, evidence of sepsis or infection, and development of anesthetic complications during surgical correction of the defect. Foals developing UP while in the hospital frequently had a history of dystocia and presented at a very young age (< ...
Scotty NC, Evans TJ, Giuliano E, Johnson PJ, Rottinghaus GE, Fothergill AW, Cutler TJ.Lufenuron is a benzoylphenyl urea-derived insecticide that has been recently introduced as a novel treatment for fungal infections in horses. The purposes of this study were to determine (1) the in vitro efficacy of lufenuron against Aspergillus and Fusarium spp. and (2) the ability of lufenuron to reach efficacious blood concentrations after PO administration in horses. Fungal colonies isolated from diseased equine corneas were tested against lufenuron solutions up to 700 microg/mL. Twenty-one adult horses received 1 of 3 PO lufenuron treatment regimens: 5 mg/kg body weight (BW) q24h for 3 da...
Getman LM, Ross MW, Elce YA.To report the diagnosis and outcome after surgical correction of bilateral distal ureteral anomalies in a Standardbred filly. Methods: Clinical case report. Methods: An 8-month-old, 310 kg Standardbred filly with left ureteral atresia and right ureteral ectopia. Methods: The filly was admitted for evaluation of incontinence since birth and severe urine scalding of the hindquarters. Diagnosis was made by both direct (cystoscopy and vaginoscopy) and indirect (intravenous pyelography, ultrasonography, and scintigraphy) evaluation of the ureters and bladder. The filly had left ureteral atresia, hy...
Sponseller BT, Valberg SJ, Tennent-Brown BS, Foreman JH, Kumar P, Timoney JF.Four Quarter Horses (9 months to 7 years of age) with submandibular lymphadenopathy and firm muscles (palpation of which elicited signs of pain) were evaluated; in general, the horses had a stiff gait, and 3 horses became recumbent. Streptococcus equi was cultured from aspirates of lymph nodes or samples of purulent material collected from the auditory tube diverticula. Once the horses were recumbent, their condition deteriorated rapidly despite aggressive antimicrobial and antiinflammatory treatment, necessitating euthanasia within 24 to 48 hours. One horse did not become recumbent and recove...
Rubio-Martínez L, López-Sanromán J, Cruz AM, Santos M, San Román F.To study the pharmacokinetics of vancomycin in plasma obtained from the medullary sinusoids of the proximal phalanx (P1) after intravenous (IV) and intraosseous (IO) regional limb perfusion (RLP). Methods: Experimental study. Methods: Twelve horses. Methods: IV and IO RLP were performed in 2 groups (n = 6) of horses. Vancomycin hydrochloride (300 mg in 60 mL 0.9% NaCl) was randomly infused in 1 front limb, with the contralateral limb as control (60 mL 0.9% NaCl). A hole was drilled in the lateral cortex of P1, and blood samples from the medullary sinusoids of P1 were collected before infusion,...
Morsy TA, Salem HS, Haridy FM, Rifaat MM, Abo-Zenadah NY, Adel el-Kadi M.To continue the study on fascioliasis in Tamyia Center, some farm animals were investigated for natural infection with Fasciola species by stool examination. The results showed 40% infection in sheep, 20% in buffalos, 6.7% in donkeys and zero% in horses. The overall percentage of infection was 25.5. The sheep (total dose 1800mg) and the donkey (total dose (4500 mg.) were successfully treated with Mirazid. On the other hand, one buffalo was successfully treated by a total dose 7500mg, the seconds one did not cured, but the eggs deposited per gm markedly decreased.
Weaver RW, Entry JA, Graves A.Livestock are known contributors to stream pollution. Numbers of fecal streptococci and Escherichia coli in manure naturally deposited by livestock in the field are needed for activities related to bacterial source tracking and determining maximum daily bacterial loading of streams. We measured populations of fecal streptococci and E. coli in fresh and dry manure from cattle (Bos taurus L.), horses (Equus caballus L.), and sheep (Ovis aires L.) on farms in southern Idaho. Populations of indicator bacteria in dry manure were often as high as that in fresh manure from horse and sheep. There was ...
Jacobsen S, Niewold TA, Halling-Thomsen M, Nanni S, Olsen E, Lindegaard C, Andersen PH.The aim of the study was to determine the intraarticular serum amyloid A (SAA) response pattern in horses with inflammatory arthritis. Inflammatory arthritis was induced by injection of lipopolysaccharide (LPS) into the radiocarpal joint of four horses. Serum and synovial fluid (SF) samples were collected before and at 4, 8, 12, 24, 48, 72, 96, and 144 h after injection. Concentrations of SAA were measured by immunoturbidometry, and expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. The LPS injection caused systemic and local clinical signs of in...
Feary DJ, Hyatt D, Traub-Dargatz J, Roach S, Jones RL, Wu CC, Morley PS.The objective of this study was to investigate the perceived increase in resistance of Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) isolated from the lower respiratory tract of horses to trimethoprim-sulfamethoxazole (SXT). The recorded SXT-susceptibility results of 50 S. zooepidemicus isolates from the tracheal wash fluid of equine patients examined at Colorado State University Veterinary Teaching Hospital from each of 2 time periods (1987-1990 and 1997-2001) were compared and statistically analyzed using a cross-sectional study design. There was a statistically significant diff...
Guida N, Mesplet M, Di Gennaro E, Digilio P, Moras EV.Aspergillus fumigatus is a cosmopolitan opportunistic fungal associated to rhinopharyngitis, sinusitis and guttural pouches infection with nasal discharges. All them are similar with Strangle's sign, the infectious disease produced by Streptococcus equi spp. The aim of this work was to detect A. fumigatus in healthy horses living in boxes and field. 226 nasopharyngeal swabbing samples were obtained by mycological routine. A. fumigatus was isolated in 26 (11.5%) horses.
Hoane JS, Gennari SM, Dubey JP, Ribeiro MG, Borges AS, Yai LE, Aguiar DM, Cavalcante GT, Bonesi GL, Howe DK.Sera from 961 horses from Brazil were tested for antibodies against the major surface antigens SnSAG4 and NhSAG1 to determine the seroprevalence of Sarcocystis neurona and Neospora hughesi, respectively. Antibodies against SnSAG4 were detected in 669 (69.6%) of the horses, while antibodies against NhSAG1 were detected in only 24 (2.5%) of the horses. These serologic results suggest that there is a high concentration of S. neurona in the environment of Brazil, which results in marked exposure of horses to this parasite. Additionally, the data further confirm that infection with Neospora spp. is...
Deem DA, Harrington DD.A 15 month-old Quarter Horse colt developed severe bacterial pneumonia and effusive pleuritis. A beta-hemolytic streptococcus was isolated from a tracheal wash specimen but the colt died despite conventional therapy. The gross post mortem and histologic lesions were characteristic of pulmonary nocardiosis. Nocardia brasiliensis was isolated from the lung and bronchial lymph node.
Rütten M, Lehner A, Pospischil A, Sydler T.Listeria monocytogenes infection, although rare in horses, can lead to septicaemia, gastroenteritis and abortion or stillborn foals. Equine cerebral listeriosis has been reported, but only in newborn animals. This report describes a Freiberger gelding with severe neuronal symptoms of sudden onset. The animal collapsed within 24 h and was humanely killed. Necropsy revealed multiple small brown to reddish foci within the brain stem and pons. Histopathology demonstrated multifocal suppurative meningoencephalitis with microabscesses and occasional intra-lesional, coccoid to rod-shaped, bacteria. T...
Read AJ, Finlaison DS, Gu X, Davis RJ, Arzey KE, Kirkland PD.During the equine influenza (EI) outbreak, two assays were used in parallel to diagnose the disease, to demonstrate freedom from infection in disease control zones and ultimately to demonstrate that EI virus had been eliminated from the Australian horse population. A longitudinal study of a population of naturally infected horses was established to determine the performance characteristics of these assays.
Klei TR, Torbert B, Chapman MR, Foil L.Microfilariae of Onchocerca cervicalis were detected in midventral skin biopsy samples in 64 of 84 (76%) mixed-breed ponies greater than 2 years old from the Gulf Coast area and in 42 of 51 (82.4%) horses from Louisiana breeding herds. The number of microfilariae per 8 mm of biopsied skin (ponies) ranged from 1 to 21,570. The number of microfilariae per 6 mm of biopsied skin (horses) ranged from 8 to 55,600.
Nordengrahn A, Klingeborn B, Lindholm A, Merza M.A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to equine herpesvirus 2 in serum samples of horses. By measuring the binding to a single epitope, this blocking ELISA gives a good picture of the antibody status in the animal. The test is based on a monoclonal antibody with neutralizing activity and had a sensitivity of 94% and a specificity of 100%. Antibodies due to newly acquired infection in foals were successfully detected with this blocking ELISA.
Kinoshita Y, Niwa H, Katayama Y, Hariu K.Obligate anaerobes are important etiological agents in pneumonia or pleuropneumonia in horses, because they are isolated more commonly from ill horses that have died or been euthanized than from those that survive. We performed bacterial identification and antimicrobial susceptibility testing for obligate anaerobes to establish effective antimicrobial therapy. We used 16S rRNA gene sequencing to identify 58 obligate anaerobes and compared the results with those from a phenotypic identification kit. The identification results of 16S rRNA gene sequencing were more reliable than those of the comm...
Byrne BA, Rand CL, McElliott VR, Samitz EM, Brault SA.Dermatophilosis caused by Dermatophilus congolensis causes exudative dermatitis in a variety of species. The infection is generally limited to the cutaneous tissues, where infection is acquired from the environment and bacteria penetrate into keratinized epithelium through epithelial disruption. A 3-year-old pony filly was examined for enlarging mandibular lymph nodes during the preceding 10 months. Biopsy of the node revealed mixed and granulomatous inflammation and thick, filamentous Gram-positive bacteria. Dermatophilus congolensis, confirmed by biochemical testing and sequencing of the rib...
Herrera M, Herrera JM, Cantatore S, Aguilar J, Felipe A, Fumuso E.Uterine acute post-breeding inflammation is a physiological tissue response to the entry of exogenous elements, with persistent endometritis being the main pathology responsible for subfertility in the mare (Equus ferus caballus; Linnaeus, 1758). Mares can be classified as susceptible or resistant to endometritis according to their ability to remove intrauterine fluid within 48 hr after experimental inoculation. Endometrial biopsy is a technique that is commonly used to establish the degree of lesions that can affect the fertility of the mare. Endometrial histomorphometry is an objective and ...
Straticò P, Razzuoli E, Hattab J, Guerri G, Celani G, Palozzo A, Bonanni D, Fruscione F, Varasano V, Petrizzi L, Marruchella G.A 7-year-old Friesian stallion with a history of oesophageal stenosis, weight loss, inappetence, and recurrent hyperthermia was referred for gastroscopy. The stomach mucosa surrounding the oesophageal opening showed a large, necrotic, and ulcerated mass. On post-mortem examination, a very large, cauliflower-like neoplasm was seen, affecting non-glandular gastric mucosa. Nodular lesions were observed, scattered on the omentum, the spleen, and the liver. Microscopic findings allowed the diagnosis of gastric squamous cell carcinoma with abdominal metastasis. Biomolecular investigations demonstrat...
Porter MB, Ramirez S.Pathologic disorders of the equine neonate often develop shortly after foaling as a result of prematurity, dystocia, trauma, or septicemia. Recognition of these disorders requires routine patient assessment along with diagnostic aids, including abdominal and thoracic ultrasonography. Fortunately, modern technology affords today's equine practitioners the opportunity to use ultrasonography to advance their practice, and it is the authors' hope that this article might help in those efforts.
Trotter GW, McKinnon AO.Reproductive failure in mares can present a challenge to the attending veterinarian. Although many causes of failure to conceive or to carry to term may be easy to diagnose and treat effectively, others may be difficult. In some cases, more than one problem will be present, and both medical therapy and surgical intervention will be required to achieve a successful outcome. Pneumovagina and its sequelae remain a common cause of reproductive failure in mares. Depending on the case involved, different surgical techniques may be required to correct the problem.