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Topic:Infection
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.
Multiple small-intestine intussusceptions: a complication of purpura haemorrhagica in a horse. A Belgian draft horse stallion presented with classical signs of purpura haemorrhagica: oedema of the distal limbs, ventral abdomen and head, ecchymotic haemorrhage of mucous membranes, epistaxis, fever, lethargy, reluctance to move, and anorexia. Serum chemistry revealed a highly elevated gamma-globulin fraction. Streptococcal lymphadenitis (strangles) had been present on a neighbouring farm in the past few months. After an initial positive response to therapy with benzylpenicillin, flunixin and dexamethasone, the horse's condition deteriorated suddenly on day 4 of hospitalization, with signs...
Infection of peripheral blood mononuclear cells with neuropathogenic equine herpesvirus type-1 strain Ab4 reveals intact interferon-α induction and induces suppression of anti-inflammatory interleukin-10 responses in comparison to other viral strains. The recent increase in incidence, morbidity, and mortality of neurological disease induced by equine herpesvirus type 1 (EHV-1) has suggested a change of virulence of the virus. The exact mechanisms by which EHV-1 induces neurologic disease are not known. Environmental, viral, and host risk factors might contribute to neurological manifestation. Here, we investigated innate interferon-α (IFN-α), interleukin-10 (IL-10) and IL-4 responses after infection of equine peripheral blood mononuclear cells (PBMC) with EHV-1 using an available cytokine multiplex assay. Three viral strains representing ...
The effect of environment on interferon-gamma production in neonatal foals. While interferon-gamma (IFNγ) plays an important role in protection against viral and intracellular bacterial infections, its production in neonates is deficient. Exposure to environmental antigens can promote the maturation of the immune system of neonatal humans and mice. We hypothesize that exposure to high level of microbial components would increase the production of IFNγ in neonatal foals. To test this hypothesis, one group of foals was placed into stalls three times a week for 8 weeks. A second group of foals remained on pasture. Air samples were collected from the barn and pasture fo...
Association of Streptococcus equi with equine monocytes. Streptococcus equi (Se), the cause of equine strangles, is highly resistant to phagocytosis by neutrophils and is usually classified as an extracellular pathogen. Large numbers of the organism in tonsillar tissues during the acute phase of the disease are completely eliminated during convalescence by mechanisms not yet understood. In this study we demonstrate in an opsono-bactericidal assay and by cytometry and confocal microscopy that Se is interiorized and killed by equine blood monocytes. This finding supports the hypotheses that adaptive immune clearance is mediated by tonsillar macrophage...
Intravenous technetium-99m labelled PEG-liposomes in horses: a safety and biodistribution study. Liposomes are phospholipid nanoparticles that extravasate at sites of increased vascular permeability. They have potential in equine medicine for targeted drug delivery and diagnostic imaging of infectious, inflammatory and neoplastic lesions. Objective: This study evaluates the safety and biodistribution of i.v. polyethyleneglycol(PEG) liposomes in normal horses. Methods: PEG-liposomes were prepared by the film hydration method and labelled using (99m) Tc-hexamethyl-propylene-amine-oxime. A single dose of 0.24 µmol/kg bwt (99m) Tc-PEG-liposomes and 2.4 µmol/kg bwt unlabelled PEG-liposomes...
Observations on effects of a neem seed extract (MiteStop®) on biting lice (mallophages) and bloodsucking insects parasitizing horses. The hair of 300 horses belonging to short hair and long hair races had been routinely treated during the last 3 years with a neem seed extract (MiteStop®) in order to kill mallophages (e.g., specimens of the genus Werneckiella). It was found that in all cases, a hidden infestation with these biting lice had existed, which became visible when the product (diluted 1:20 with tap water) was brushed onto the hair. The mallophages left the body surface and became visible as a fine "wooly looking" layer at the tips of the hair. Furthermore, this treatment stopped the forming of dandruff of the skin...
Lawsonia intracellularis-specific interferon γ gene expression by peripheral blood mononuclear cells in vaccinated and naturally infected foals. The cell-mediated immune response to Lawsonia intracellularis, the agent of equine proliferative enteropathy (EPE), was investigated in vaccinated and naturally infected foals. Interferon (IFN)-γ gene expression was determined in peripheral blood mononuclear cells collected from vaccinated (n=6) and control foals (n=6) every 30 days for 180 days following first vaccine administration, and from clinically affected foals (n=16) within 7-10 days of diagnosing EPE. Seroconversion (immunoperoxidase monolayer assay titer ≥60) occurred in 5/6 vaccinated foals between 60 and 90 days following the f...
Oral absorption of clarithromycin is nearly abolished by chronic comedication of rifampicin in foals. The delivery of clarithromycin (CRL) to its site of action in bronchial/alveolar epithelial cells (EC), bronchial epithelial lining fluid (ELF), and bronchoalveolar lavage cells (BALC) may be influenced by CYP3A4 and the drug transporters, ATP-binding cassette (ABC) B1 and ABCC2 and organic anion-transporting polypeptides (OATPs), which can be modulated and/or up-regulated via the nuclear pregnane X receptor (PXR) by rifampicin (RIF). Therefore, we evaluated the disposition and pulmonary distribution of CLR (7.5 mg/kg b.i.d., 21 days) and expression of ABCB1, ABCC2, OATP1A2, and OATP2B1 in EC ...
Equine torovirus (BEV) induces caspase-mediated apoptosis in infected cells. Toroviruses are gastroenteritis causing agents that infect different animal species and humans. To date, very little is known about how toroviruses cause disease. Here, we describe for the first time that the prototype member of this genus, the equine torovirus Berne virus (BEV), induces apoptosis in infected cells at late times postinfection. Observation of BEV infected cells by electron microscopy revealed that by 24 hours postinfection some cells exhibited morphological characteristics of apoptotic cells. Based on this finding, we analyzed several apoptotic markers, and observed protein syn...
Is the skin sensitivity test required for administering equine rabies immunoglobulin? Rabies immunoglobulins are life-saving in patients with severe exposure to rabies. Despite the high degree of purification of equine rabies immunoglobulin (ERIG), the product inserts still recommend a skin sensitivity test before administration of this heterologous serum. A recent WHO recommendation states that there are no scientific grounds for performing a skin test before administering ERIG because testing does not predict reactions and it should be given irrespective of the result of the test. In this conflicting situation, we assessed the use of the skin sensitivity test in predicting ad...
Surveillance programme for important equine infectious respiratory pathogens in the USA. The prevalence and epidemiology of important viral (equine influenza virus [EIV], equine herpesvirus type 1 [EHV-1] and EHV-4) and bacterial (Streptococcus equi subspecies equi) respiratory pathogens shed by horses presented to equine veterinarians with upper respiratory tract signs and/or acute febrile neurological disease were studied. Veterinarians from throughout the USA were enrolled in a surveillance programme and were asked to collect blood and nasal secretions from equine cases with acute infectious upper respiratory tract disease and/or acute onset of neurological disease. A questionn...
Development and evaluation of a real-time polymerase chain reaction method for the detection of Mycoplasma felis. Infection by Mycoplasma felis is associated with ocular and respiratory disease in cats and respiratory disease in horses. A correct diagnosis is beneficial since the use of specific antimycoplasmal treatment can lead to resolution. The objective of the present study was to develop a real-time polymerase chain reaction (PCR) method based on dual-labeled fluorogenic probe technology, targeting the gene encoding elongation factor Tu (tuf ), for the fast and specific detection of M. felis. Specificity was achieved by basing the assay design on partial sequencing of the tuf gene in strains and cli...
Characterization of the interferon gamma response to Lawsonia intracellularis using an equine proliferative enteropathy challenge (EPE) model. Lawsonia intracellularis is the etiological agent of infectious intestinal hyperplasia for which several clinical diseases have been described including proliferative enteropathy (PE), intestinal adenomatosis, and ileitis. While initially recognized as the causative agent of PE in pigs, L. intracellularis is now viewed as an emerging cause of intestinal hyperplasia in a wide range of mammalian species, including horses. Equine proliferative enteropathy (EPE) has been reported worldwide though definitive diagnosis is difficult and the epidemiology of the disease remains poorly understood. Weanl...
Bovine papillomavirus type 1 and Equus caballus papillomavirus 2 in equine squamous cell carcinoma of the head and neck in a Connemara mare. In January 2010, 18 months after excision of an ocular squamous cell carcinoma (SCC), a Connemara mare presented with anorexia and periorbital/parotideal lesions. Post mortem examination revealed these lesions as forming one entity, with 2 additional growths in the retropharyngeal region and the left jugular groove, respectively. The lesions were confirmed histopathologically as SCCs. Using PCR, peripheral blood mononuclear cells (PBMCs) from 2008 and 2010, tumour tissue, intact skin and vulval mucosa were screened for Equus caballus papillomavirus type 2 (EcPV-2) and bovine papillomavirus typ...
Cryptosporidium parvum infection in a mare and her foal with foal heat diarrhoea. Cryptosporidium infection was molecularly investigated in mares and in their neonatal foals for which the occurrence of foal heat diarrhoea was also assessed. Thirty-seven mare/foal pairs were included in the study. All foals were born in the same stud farm during 2006-2008 breeding seasons. Two faecal samples, one prior to and one after delivery were collected from each mare, whereas three faecal samples were taken from each foal, i.e. at 8, 10 and 12 days of age. All samples (74 from mares and 111 from foals) were divided into two aliquots, one of which was examined for the presence of Crypt...
Persistent, widespread papilloma formation on the penis of a horse: a novel presentation of equine papillomavirus type 2 infection. A 9-year-old gelding presented with approximately 100 papillomas that covered about 75% of the distal penis. Biopsy was performed, and histology showed evidence of viral cytopathic change and koilocytosis. Polymerase chain reaction using DNA extracted from biopsied tissue amplified equine papillomavirus type 2 (EcPV-2) DNA sequences. Sixteen months later, the horse was re-examined and the appearance of the papillomas was unchanged. Equine papillomavirus type 2 DNA sequences were again amplified from both biopsied tissue and swabs of the penis. Papillomavirus was localized to the lesions by imm...
Lower airway disease, now and in the future. Respiratory disease is an important cause of wastage in the Thoroughbred industry and is a cause of welfare problems in all types of horse. This review concerns developments in our understanding of equine respiratory disease since 1998 and illustrates how strategic funding from the Horserace Betting Levy Board has contributed to this understanding.
Radiological anatomy of the donkey’s foot: objective characterisation of the normal and laminitic donkey foot. Anatomical change within a laminitic foot is of diagnostic and prognostic importance. A lateromedial radiograph represents the current 'gold standard' by which these changes are identified. Detection of anatomical change is dependent upon a priori knowledge of normality and subjective assessment alone may not identify modest change. Normal baseline data is, therefore, needed against which objective comparisons can be made. There is little information regarding the radiological anatomy of the donkey foot, hence an equine model has been widely adopted. However, descriptive accounts suggest funda...
Serial use of serologic assays and fecal PCR assays to aid in identification of subclinical Lawsonia intracellularis infection for targeted treatment of Thoroughbred foals and weanlings. To assess the serial use of serum immunoperoxidase monolayer assays (IPMAs) and fecal PCR assays, combined with other diagnostic methods, to identify subclinical Lawsonia intracellularis infections for targeted treatment of Thoroughbred foals and weanlings at farms in which the pathogen was endemic or nonendemic. Methods: Evaluation study. Methods: 100 foals and weanlings (53 and 47 at farms in which L intracellularis was endemic and nonendemic, respectively). Methods: Serum was collected every 4 weeks and tested via IPMA, for antibodies against L intracellularis. Fecal samples were collected ...
Impaired efficacy of ivermectin against Parascaris equorum, and both ivermectin and pyrantel against strongyle infections in trotter foals in Finland. In order to assess the resistance situation against macrocyclic lactones in Parascaris equorum and against tetrahydropyrimidine derivatives in strongyles in Finnish trotter horses, 112 foals on 18 farms, mostly 1 year old, were examined for these parasites with a modified McMaster faecal flotation method. P. equorum positive foals (n=24) were given ivermectin orally at a dose of 200 μg/kg b.w., while strongyle positive but P. equorum negative foals (n=38) received pyrantel embonate orally at a dose of 19 mg/kg. Sixteen P. equorum infected foals, treated with ivermectin, also harboured strongy...
Immune response to Rhodococcus equi ATCC 33701-secreted proteins in mice and identification of immunogenic recombinant proteins by dot-blotting. Rhodococcus equi remains a significant pathogen, causing severe pneumonia in foals. The development of vaccines and serologic diagnosis could be greatly facilitated by studying the humoral immune response to this equine pathogen. In this study, a crude extract of R. equi ATCC 33701-secreted proteins combined with the Montanide® ISA70 adjuvant was found to be highly immunogenic in mice with the highest titer of 99,000 on day 42 after the first subcutaneous immunization. This immune response was dependent on the quantity of proteins injected and the presence of adjuvant. By dot-blotting, eight ...
Observations on development of natural infection and species composition of small strongyles in young equids in Kentucky. Early development and maturation of species of small strongyles have not been studied extensively. Most information is on the first appearance of strongyle eggs in feces of foals. However, species cannot be determined in this manner because of similarity of the morphological features of the eggs. To determine more definitive knowledge on development and species composition of natural infections of small strongyles, eight equid foals were necropsied and examined at various ages (31 to 92 days of age). The entire contents of the large intestine were examined, and all worms (6,671) recovered were...
Prevalence of methicillin-resistant Staphylococci on a farm: staff can harbour MRS when animals do not. The aim of this work was to establish the prevalence of methicillin-resistant Staphylococci (MRS) in the animals and staff of a teaching and research farm. Samples of dairy cattle (36), beef cattle (26), sheep (19), horses (21), pigs (23), goats (23) and humans (13) were collected and screened for the presence of MRS. The detection of mecA gene was performed by PCR to determine the resistance of the samples to methicillin. Antimicrobial-resistance testing to penicillin, meropenem, ceftriaxone, cephalothin, oxacillin, levofloxacin, enrofloxacin, chloramphenicol, ciprofloxacin, gentamicin, clind...
Facing the threat of equine parasitic disease. Horses worldwide are exposed to a complex mixture of intestinal parasitic helminths. When burdens are high, these parasites can seriously compromise health and welfare. Some helminth species have an extremely high prevalence and are difficult to control, not least because there is a limited understanding of their most basic biology. Furthermore, levels of resistance to some of the commonly used anthelmintics are widespread and increasing. The cyathostomins are the most common nematode species affecting equids worldwide. Within this group of parasites are more than 50 different species. Until r...
Putative intestinal hyperammonaemia in horses: 36 cases. Intestinal hyperammonaemia (HA) has been infrequently reported in individual horses; however, there have been no studies describing clinical and laboratory data as well as short- and long-term outcome in a larger number of cases. Objective: To describe clinical and laboratory data and short- and long-term outcome in a large group of horses with intestinal HA. Methods: Multi-centred, retrospective study; case records of horses with HA were reviewed and any horse with a clinical or post mortem diagnosis of intestinal HA was included. Hyperammonaemia was defined as a blood ammonium (NH(4) (+)) co...
Consistent detection of bovine papillomavirus in lesions, intact skin and peripheral blood mononuclear cells of horses affected by hoof canker. Equine hoof canker is a chronic proliferative pododermatitis of as yet unknown aetiology. Like equine sarcoid disease, canker is a therapy-resistant disorder characterised by hyperkeratosis, acanthosis and a marked tendency to recur. Objective: There is an association of sarcoid-inducing bovine papillomaviruses of types 1 and 2 (BPV-1, BPV-2) with hoof canker disease. Methods: Using PCR-based techniques, we assessed canker tissue, intact skin and/or peripheral blood mononuclear cells (PBMCs) of 25 canker-affected horses for the presence of sarcoid-associated BPV-1 and -2. Results: Conventional...
Etiologic and epidemiologic analysis of bacterial infectious upper respiratory disease in Thoroughbred horses at the Seoul Race Park. Infectious upper respiratory disease (IURD) of Thoroughbred racehorses has been a frequent problem (29.6% of incidence) at the Seoul Race Park (Korea). Risk factors for IURD include the season with a high transfer rate (summer and fall), the stabling period (≤ 3 months), and age (2 to 3 years old), suggesting that the movement and new environment may have depressed the immune system of the horses and decreased their ability to respond properly to pathogens. The bacterial strains (n = 98) isolated from IURD horses included Pseudomonas spp., Escherichia coli, Staphylococcus spp., Streptococcus...
Serum antibody responses in horses and mice following immunization with Actinobacillus equuli outer membrane proteins and recombinant Aqx toxin. The immune responsiveness of mice (without prior natural exposure) and mares (with naturally acquired antibodies) was determined following vaccination with Actinobacillus equuli outer membrane proteins (OMPs) and/or recombinant A. equuli toxin (rAqx). Mice were vaccinated subcutaneously on days 0 and 21 with one of three doses (5, 25 or 50μg) of A. equuli OMPs, rAqx or both, together with Freund's incomplete adjuvant (FIA). Antibodies against formalin-killed whole bacterial cells (WBCs), OMPs and Aqx were determined on days 0, 21 and 42. Mares were vaccinated subcutaneously on days 0 and 21 w...
