Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Direct agglutination test for the detection of antibodies to Sarcocystis neurona in experimentally infected animals. Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in the Americas. The apicomplexan protozoan most commonly associated with EPM is Sarcocystis neurona. A direct agglutination test (SAT) was developed to detect antibodies to S. neurona in experimentally infected animals. Merozoites of the SN6 strain of S. neurona collected from cell culture were used as antigen and 2-mercaptoethanol was added to the antigen suspension to destroy IgM antibodies when mixed with test sera. Mice fed sporocysts of S. speeri or S. falcatula-like sporocysts from opossums did not sero...
Immunoconversion against Sarcocystis neurona in normal and dexamethasone-treated horses challenged with S. neurona sporocysts. Equine protozoal myeloencephalitis is a common neurologic disease of horses in the Americas usually caused by Sarcocystis neurona. To date, the disease has not been induced in horses using characterized sporocysts from Didelphis virginiana, the definitive host. S. neurona sporocysts from 15 naturally infected opossums were fed to horses seronegative for antibodies against S. neurona. Eight horses were given 5x10(5) sporocysts daily for 7 days. Horses were examined for abnormal clinical signs, and blood and cerebrospinal fluid were harvested at intervals for 90 days after the first day of chall...
Characterization of a Sarcocystis neurona isolate from a Missouri horse with equine protozoal myeloencephalitis. Little information is available about antigenic variation of Sarcocystis neurona isolated from horses with equine protozoal myeloencephalitis, nor is there much information available on the specific antibody pattern to S. neurona antigens of horses from different geographic regions where S. neurona isolates have been obtained. This communication reports on the characterization of a new S. neurona isolate, SN-MU1. The isolate was obtained from a 3-year old Thoroughbred that had asymmetrical neurological signs and localized skeletal muscle atrophy. This S. neurona isolate is similar to other S. ...
Comparison of Sarcocystis neurona isolates derived from horse neural tissue. Sarcocystis neurona is a protozoan parasite that can cause neurological deficits in infected horses. The route of transmission is by fecal-oral transfer of sporocysts from opossums. However, the species identity and the lifecycle are not completely known. In this study, Sarcocystis merozoites from eight isolates obtained from Michigan horses were compared to S. neurona from a California horse (UCD1), Sarcocystis from a grackle (Cornell), and five Sarcocystis isolates from feral opossums from Michigan. Comparisons were made using several techniques. SDS-PAGE analysis with silver staining showed...
Ultrastructure of schizonts and merozoites of Sarcocystis neurona. The ultrastructure of Sarcocystis neurona schizonts and merozoites was studied in specimens derived from cell culture and from the brains of infected mice. Schizonts and merozoites were located in the host cell cytoplasm without a parasitophorous vacuole at any stage of development. Merozoites divided by endopolygeny. Fully formed merozoites had a pellicle, numerous polysomes and ribosomes, smooth and rough endoplasmic reticulum, 22 subpellicular microtubules, 9-16 dense granules, 25-75 micronemes, a plastid, a Golgi complex, 1-3 mitochondria, a conoid, 2 apical rings, 2 polar rings, 0-6 lipid...
Antigenic and molecular analyses reveal that the equine rotavirus strain H-1 is closely related to porcine, but not equine, rotaviruses: interspecies transmission from pigs to horses? We have sequenced the genes encoding the inner capsid protein VP6 and the outer capsid glycoprotein VP7 of the subgroup (SG) I equine rotavirus strain H-1 (P9[7], G5). The VP6 and VP7 proteins of the equine rotavirus strain H-1 shared a high degree of sequence and deduced amino acid identity with SG I porcine strains and serotype G5 porcine strains, respectively. Previous sequence analyses of the genes encoding the outer capsid spike protein VP4 and the nonstructural proteins NSP1 and NSP4 of equine H-1 strain also revealed a high degree of sequence and deduced amino acid homology with the pro...
Borna disease in horses. Borna disease is a sporadically occurring, progressive viral polioencephalomyelitis that primarily affects horses and sheep. The etiological agent, Borna disease virus (BDV), is an enveloped, single-stranded RNA virus that has been classified in the new virus family Bornaviridae within the order Mononegavirales. Serological evidence of BDV infection has been found in an increasing number of countries throughout the world. After an incubation period lasting a few weeks to several months, BDV infection can cause locomotor and sensory dysfunction followed by paralysis and death. Borna disease is ...
Fistulation of the auditory tube diverticulum (guttural pouch) with a neodymium:yttrium-aluminum-garnet laser for treatment of chronic empyema in two horses. Two horses with chronic empyema of the auditory tube diverticulum (guttural pouch) were refractory to medical treatment; empyema was bilateral in 1 horse and unilateral in the other. Both horses were treated by fistulation of the cartilage of the pharyngeal orifice by use of a neodymium:yttrium-aluminum-garnet laser in a noncontact manner. To maintain patency of the fistulae, indwelling catheters were placed into the openings created by the laser. For both horses, long-term follow-up did not reveal complications, and both owners were satisfied with results of the procedure. The authors recomme...
Antimicrobic and anthelmintic resistance. Antimicrobial and anthelmintic resistance are growing issues for the equine practitioner. The development of antimicrobial or anthelmintic resistance is a source of significant concern because of increased frequency of treatment failures and increased treatment costs. In addition, antimicrobial resistance may have important consequences for public health. Only through judicious use can the efficacy of antimicrobials and anthelmintics be prolonged. This article discusses the development of resistance and suggestions for control.
Diagnosis of eastern equine encephalitis by immunohistochemistry in two flocks of Michigan ring-neck pheasants. The diagnosis of eastern equine encephalitis (EEE) virus infection in avian species is relatively difficult when compared with other species. There are no characteristic histologic lesions in the avian brain that would serve to distinguish EEE from infections with, for example, Newcastle disease or highly pathogenic avian influenza virus. Traditionally, virus isolation (VI) and/or hemagglutination inhibition (HI) has been used for a definitive diagnosis of EEE in birds. Recently, we developed an immunohistochemistry (IHC) technique for confirmatory diagnosis of EEE infection in equine brain. T...
Neurological signs in a horse due to metastases of an intestinal adenocarcinoma. 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.
Equine protozoal myeloencephalitis. Recent advances in the understanding of the parasite life cycle, epidemiology, clinical signs, diagnosis, treatment, and prevention of EPM are reviewed. The NAHMS Equine '98 study and a controlled retrospective study from The Ohio State University College of Veterinary Medicine identified a number of risk factors associated with development of the disease. The national annual incidence of EPM was 1% or less depending on the primary use of the animals. Increased disease risk was associated with age (1-5 and > 13 years of age), season (lowest in winter months and increasing with ambient tempe...
A random amplified polymorphic DNA polymerase chain reaction technique that differentiates between Neospora species. Neospora caninum is a recently described coccidial parasite that was first isolated from a dog in 1988 and has subsequently been shown to infect a wide range of mammals. Neospora hughesi, a new species of this genus, has recently been isolated from the spinal cord of horses showing clinical signs of equine protozoal myeloencephalitis. The random amplified polymorphic DNA polymerase chain reaction technique is capable of differentiating between N. caninum and N. hughesi.
Hendra and Nipah virus infections. The most important clinical and pathological manifestation of Hendra virus infection in horses and humans is that of severe interstitial pneumonia caused by viral infection of small blood vessels. The virus is also capable of causing nervous disease. Hendra virus is not contagious in horses and is spread by close contact with body fluids, such as froth from infected lungs. Diagnosis should be based on the laboratory examination of blood, lung, kidney, spleen, and, if nervous signs are present, also of the brain. Evidence of infection with the more recently identified and related Nipah virus wa...
Acute thrombosis of limb arteries in horses with sepsis: five cases (1988-1998). A hypercoagulable condition and poor perfusion to distal extremities might occur during equine endotoxaemic or septic shock, which could cause thrombosis of limb arteries. In our review, thrombosis occurred in neonatal foals in association with gram-negative bacteraemia. In 3 older foals and adults, thrombosis was associated with inflammatory bowel disease, diarrhoea and toxaemia. All patients had been treated with broad-spectrum antibiotics, nonsteroidal antiinflammatory drugs and i.v. crystalloid solutions. Two horses received i.v. hyperimmune plasma. A generalised coagulopathy was not suspe...
Caecocaecal and caecocolic intussusceptions associated with larval cyathostomosis in four young horses. This report describes the clinical and pathological features of 4 horses affected by caecocaecal or caecocolic intussusceptions associated with larval cyathostomiasis. In each case, there was clinical and/or pathological evidence of concurrent larval cyathostomosis. They all demonstrated variable signs including diarrhoea, pyrexia, weight loss and subcutaneous oedema and cyathostome larvae were identified in the faeces of 3 of the horses. These cases highlight the need to consider caecal intussusceptions as a possible complication in horses affected by larval cyathostomosis, especially where s...
Design and clinical use of a modified colon tray for large colon evacuation in the horse. A modified colon tray to perform large colon evacuations in horses was designed. A funnel-shaped accessory was constructed to create a mechanical separation between the sterile and nonsterile part of the tray. Sterile hooks were used to make a temporary and stabile colostomy. Thirty horses with surgical correction of nonstrangulating large colon obstruction underwent a large colon evacuation with this modified tray. The surgical procedure was uncomplicated and resulted in a positive outcome in 29 horses. This less labour-intensive way to evacuate the large colon results in minor contamination ...
Emergent causes of placentitis and abortion. The clinical signs, laboratory findings, diagnosis, epidemiology, treatment, and prevention and control of two emerging causes of placentitis and abortion in horses are described in this article. Leptospirosis has been reported as a significant cause of fetal loss in horses in Kentucky, Northern Ireland, and England. Most abortions result from infection by serovars kennewicki or bratislava. Nocardioform placentitis has become the most common cause of placentitis in central Kentucky horses. Nocardioform placentitis is associated with infection by unnamed, gram-positive, filamentous, branching b...
Evaluation of polymyxin B in an ex vivo model of endotoxemia in horses. To evaluate effects of polymyxin B sulfate (PMB) on response of horses to endotoxin, using an ex vivo model. Methods: 8 healthy horses. Methods: In a crossover design, 3 doses of PMB (100, 1,000, and 10,000 U/kg of body weight) and physiologic saline solution (control) were evaluated. Prior to and for 24 hours after administration of PMB, blood samples were collected into heparinized tubes for use in 2 assays. For the endotoxin-induced tumor necrosis factor (TNF) assay, blood samples were incubated (37 C for 4 h) with 1 ng of Escherichia coli or Salmonella Typhimurium endotoxin/ml of blood. Pl...
Getah virus as an equine pathogen. Getah virus is a member of the genus Alphavirus in the family Togaviridae and has been frequently isolated from mosquitoes. Seroepizootiologic studies indicate that the virus is mosquito-borne and widespread, ranging from Eurasia to southeast and far eastern Asia, the Pacific islands, and Australasia. The natural host animal of the virus was not known until the first recognized occurrence of Getah virus infection among racehorses in two training centers in Japan in 1978. Outbreaks of clinical disease due to Getah virus infection occur infrequently, and only one outbreak has been reported outsi...
Investigation of an outbreak of tapeworm-associated colic in a training yard. A novel serological assay which measures IgG(T) specific for a 12/13 kDa protein of the equine tapeworm Anoplocephala perfoliata was used as part of a colic outbreak investigation. A training/rehabilitation yard for Thoroughbreds and Arabs was found to have an increasing incidence of colic over a 5 year period, culminating in a peak incidence of 1.15 episodes/horse year at risk. Four animals suffered from ileal impaction colic which necessitated surgical management. A case-control study design suggested a strong association between tapeworm infection and colic, with evidence of a dose-response...
Laboratory vector competence of black flies (Diptera:Simuliidae) for the Indiana serotype of vesicular stomatitis virus. In previous experiments we have demonstrated that colonized and wild black flies are competent laboratory vectors of different Mexican and Western USA isolates of vesicular stomatitis virus, serotype New Jersey (VSV-NJ). We have recently demonstrated biological VSV-NJ transmission by black flies using animal models. In the study described here, we tested the vector competence of colonized and wild black flies for the vesicular stomatitis virus, serotype Indiana (VSV-IN). A 1998 equine isolate was used. After a 10 day incubation period, saliva from experimentally infected Simulium vittatum and ...
Clostridial enterocolitis. Equine clostridial enterocolitis is being recognized with increasing frequency. It has been identified in foals with diarrhea, antibiotic-associated enterocolitis, or nosocomial enterocolitis. The sporadic occurrence of clostridial enterocolitis, the variety of types of clostridia involved, and the difficulty of experimentally reproducing the disease suggest that it is a poorly defined multifactorial syndrome. The risk factors associated with susceptibility to colonization and progressive infection are largely based on anecdotal observations and extrapolation from human studies. Quantitative s...
The medical management of eight horses with grade 3 rectal tears. Eight horses with Grade 3b rectal tears of the peritoneal part of the rectum or small colon were treated by a combination of medical therapy and dietary manipulation. All of the horses developed septic peritonitis during the course of treatment. Medical therapy consisted of a combination of penicillin, gentamicin and flunixin meglumine administered parenterally, metronidazole administered orally and liquid paraffin administered by nasogastric tube. Some horses also received fluid and electrolyte therapy i.v., plasma and heparin i.v. All horses were maintained on a laxative diet. Six of the 8 h...
Administration of ticarcillin in combination with clavulanic acid intravenously and intrauterinely to clinically normal oestrous mares. Ticarcillin and clavulanic acid (potassium clavulanate) were administered to normal oestrous mares intravenously (i.v.) at a dose of 50 and 1.67 mg/kg for ticarcillin and clavulanate, respectively. In a crossover design, the same drugs were administered intrauterine (i.u.) at a dose of 12.4 and 0.4 mg/kg for ticarcillin and clavulanate, respectively. The i.u. dose was administered in 100 mL of saline solution. Endometrial tissue biopsies and plasma samples were collected after drug administration for the determination of ticarcillin and clavulanate concentrations by high-pressure liquid chroma...
Heterologous expression of lacticin 3147 in Enterococcus faecalis: comparison of biological activity with cytolysin. Lacticin 3147 is a broad-spectrum, two-component, lanthionine-containing bacteriocin produced by Lactococcus lactis DPC3147 which has widespread food and biomedical applications as a natural antimicrobial. Other two-component lantibiotics described to date include cytolysin and staphylococcin C55. Interestingly, cytolysin, produced by Enterococcus faecalis, has an associated haemolytic activity. The objective of this study was to compare the biological activity of lacticin 3147 with cytolysin. The lacticin 3147-encoding determinants were heterologously expressed in Ent. faecalis FA2-2, a plasm...
Isolation and characterization of an equine foamy virus. Foamy viruses (FVs) are complex retroviruses which have been isolated from different animal species including nonhuman primates, cattle, and cats. Here, we report the isolation and characterization of a new FV isolated from blood samples of horses. Similar to other FVs, the equine foamy virus (EFV) exhibits a highly characteristic ultrastructure and induces syncytium formation and subsequent cell lysis on a large number of cell lines. Molecular cloning of EFV reveals that the general organization is that of other known FVs, whereas sequence similarity with its bovine FV counterpart is only 40%...
Phylogenetic analysis of partial mitochondrial cytochrome oxidase c subunit I and large ribosomal RNA sequences and nuclear internal transcribed spacer I sequences from species of Cyathostominae and Strongylinae (Nematoda, Order Strongylida), parasites of the horse. Three nucleotide data sets, one nuclear (ITS-2) and two mitochondrial (COI and l-rRNA), have been investigated in order to determine relationships among species of Strongylinae and Cyathostominae, intestinal parasites of the horse. The data exhibited a strong mutational bias towards A and T and in the COI gene, silent sites appeared to saturate rapidly partly due to this substitution bias. Thus, the COI gene was found to be less phylogenetically informative than the l-rRNA and ITS-2 genes. Combined analysis of the l-rRNA and ITS-2 genes supported a monophyletic clade of the cyathostomes with T...
The equine herpesvirus 1 immediate-early protein interacts with EAP, a nucleolar-ribosomal protein. The equine herpesvirus 1 (EHV-1) immediate-early (IE) phosphoprotein is essential for the activation of transcription from viral early and late promoters and regulates transcription from its own promoter. The IE protein of 1487 amino acids contains a serine-rich tract (SRT) between residues 181 and 220. Deletion of the SRT decreased transactivation activity of the IE protein. Previous results from investigation of the ICP4 protein, the IE homolog of herpes simplex virus 1 (HSV-1), revealed that a domain containing a serine-rich tract interacts with EAP (Epstein-Barr virus-encoded small nuclear...
