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Topic:Infectious Disease
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.
A comparison of the intestinal helminth communities of Equidae in Southern Africa. The intestinal helminth communities of 8 horses, 12 donkeys, 21 Hartmann's mountain zebras, and 44 Burchell's zebras were compared using the original data from 6 studies in South Africa and Namibia. Necropsy and worm recovery techniques were comparable between the studies. Sixty helminth species (58 nematode, 1 cestode, and 1 trematode species) were recorded. There were significant differences in the helminth community structures of the 4 Equus species. The helminth communities of the 2 closely related zebra subspecies were most similar, and they jointly shared 7 helminth species with donkeys ...
Immune response to vaccines based upon the VapA protein of the horse pathogen, Rhodococcus equi, in a murine model. Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results sh...
Experimental infection of ponies with Sarcocystis fayeri and differentiation from Sarcocystis neurona infections in horses. Sarcocystis neurona and Sarcocystis fayeri infections are common in horses in the Americas. Their antemortem diagnosis is important because the former causes a neurological disorder in horses, whereas the latter is considered nonpathogenic. There is a concern that equine antibodies to S. fayeri might react with S. neurona antigens in diagnostic tests. In this study, 4 ponies without demonstrable serum antibodies to S. neurona by Western immunoblot were used. Three ponies were fed 1 x 10(5) to 1 x 10(7) sporocysts of S. fayeri obtained from dogs that were fed naturally infected horse muscles. A...
Measurement of serum IgG in foals by radial immunodiffusion and automated turbidimetric immunoassay. Hypogammaglobulinemia as a result of failure of transfer of passive immunity (FTPI) is an important risk factor for infectious disease in neonatal foals. The current gold standard for determining serum immunoglobulin concentrations is radial immunodiffusion (RID). The purpose of this study was to compare immunoglobulin concentrations measured by RID with those determined by an automated turbidimetric immunoassay (TIA), which has a much shorter turnaround time. Immunoglobulin concentrations were measured by both RID and TIA in serum collected from 84 neonatal foals. Sixty-seven foals had result...
Immunologic responses to West Nile virus in vaccinated and clinically affected horses. To compare neutralizing antibody response between horses vaccinated against West Nile virus (WNV) and horses that survived naturally occurring infection. Methods: Cross-sectional observational study. Methods: 187 horses vaccinated with a killed WNV vaccine and 37 horses with confirmed clinical WNV infection. Methods: Serum was collected from vaccinated horses prior to and 4 to 6 weeks after completion of an initial vaccination series (2 doses) and 5 to 7 months later. Serum was collected from affected horses 4 to 6 weeks after laboratory diagnosis of infection and 5 to 7 months after the first...
Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine e...
The EICP27 protein of equine herpesvirus 1 is recruited to viral promoters by its interaction with the immediate-early protein. The equine herpesvirus 1 (EHV-1) EICP27 protein cooperates with either the immediate-early (IE) or the EICP0 protein to synergistically trans-activate viral promoters. GST-pulldown and co-immunoprecipitation assays revealed that the EICP27 protein's cooperation with the IE or the EICP0 protein involves its physical interaction with these viral proteins. In the case of the IE-EICP27 protein interaction, IE residues 424 to 826 and EICP27 residues 41 to 206 harbor the interactive domains. Electrophoretic mobility shift assays (EMSA) suggested that the EICP27 protein is not a sequence-specific DNA...
West Nile virus and North America: an unfolding story. Before the introduction of the West Nile virus (WNV) into the United States of America (USA) in 1999, conditions in North America were ideal for an arboviral epidemic. Such factors as the large, susceptible and non-immune animal and human populations, the presence of competent vectors, increasing international travel and commerce, existing methods for rapid dissemination and an ill-prepared animal and public health infrastructure all combined to create the essential elements for a severe animal and public health crisis--the 'perfect microbial storm'. The introduction of WNV into New York City ...
Detection of antibodies to Borrelia burgdorferi in naturally infected horses in the USA by enzyme-linked immunosorbent assay using whole-cell and recombinant antigens. Blood samples were collected from 98 horses suspected of having borreliosis or granulocytic ehrlichiosis in Connecticut and New York State, USA during 1985, 1995, and 1996. Serum antibodies to Borrelia burgdorferi were detected by an enzyme-linked immunosorbent assay (ELISA), based on whole-cell and recombinant antigens, in 82 (84%) horses. Of the 181 sera tested, 59% were positive, using whole-cell antigens, compared to 48% with protein (p)37 and 35% with VlsE antigens. An ELISA containing either of these fusion proteins can be used as an adjunct to general screening by an ELISA or immunoblot...
Microbiologic and pathologic findings in an epidemic of equine pericarditis. During the spring and summer of 2001 and in association with the mare reproductive loss syndrome, 22 terminal and 12 clinical cases of equine pericarditis were diagnosed in central Kentucky. Actinobacillus species were the principal isolates from 8 of 10 nontreated, terminally affected and 3 of 10 clinically affected horses. Enterococcus faecalis and Streptococcus zooepidemicus were cultured from the remaining 2 nontreated terminal cases. No viruses were isolated in tissue culture. Nucleic acid of equine herpesvirus-2 was detected in pericardial and tracheal wash fluids of 3 and 1 individuals,...
Use of a Bayesian risk-mapping technique to estimate spatial risks for mare reproductive loss syndrome in Kentucky. To estimate spatial risks associated with mare reproductive loss syndrome (MRLS) during 2001 among horses in a specific study population and partition the herd effects into those attributable to herd location and those that were spatially random and likely attributable to herd management. Animals-Pregnant broodmares from 62 farms in 7 counties in central Kentucky. Methods: Veterinarians provided the 2001 abortion incidence proportions for each farm included in the study. Farms were georeferenced and data were analyzed by use of a fully Bayesian risk-mapping technique. Results: Large farm-to-fa...
Molecular detection of Leptospira kirschneri in tissues of a prematurely born foal. Leptospirosis was identified to be the possible cause of premature birth in a foal on a farm with a history of repeated abortions. Using an appropriate polymerase chain reaction (PCR) assay, the presence of Leptospira kirschneri was detected in the tissues of the prematurely born foal. Further confirmation of L. kirschneri was obtained by nucleotide sequence analysis of the PCR-amplified DNA fragment and the partial 16S ribosomal RNA gene sequence. This report further supports mounting evidence that a PCR assay capable of detecting L. kirschneri should be included in routine diagnostic investi...
Diagnostic application of immunoperoxidase monolayer assay using monoclonal antibodies produced against equine arteritis virus 14-kDa nucleocapsid protein. Two monoclonal antibodies against the Bucyrus strain of equine arteritis virus (EAV) were produced, and according to immunoperoxidase reaction following Western blot of electrophoresed EAV structural proteins, they recognized the nucleocapsid (N) protein antigen (14-kDa protein). Besides reacting with the blotted polypeptide, the antibodies of the two clones (designated 1H1 and 4G6) selected from 576 have shown high affinity and specificity to intracellular virus antigen as well. Both antibodies reacted with the representatives of the different subtypes of equine arteritis virus providing a su...
Characterization of a 2.6 kbp variable region within a class 1 integron found in an Acinetobacter baumannii strain isolated from a horse. A complete gene cassette contained in a class 1 integron from a multidrug-resistant (MDR) isolate of Acinetobacter baumannii cultured from a horse was characterized by molecular methods. Methods: Template genomic DNA purified from the A. baumannii isolate was investigated by PCR. A gene cassette-associated amplicon was detected and completely characterized. Results: A 2.6 kbp DNA fragment containing four gene cassettes was amplified from the MDR A. baumannii isolate. Sequence analysis showed it was similar to sequences recently reported in Klebsiella pneumoniae, Serratia marcescens and an Esch...
PCR ribotyping of Clostridium difficile isolates originating from human and animal sources. Molecular typing of Clostridium difficile isolates from animals and humans may be useful for evaluation of the possibility for interspecies transmission. The objective of this study was to evaluate C. difficile isolates from domestic animals and humans using PCR ribotyping. Isolates were also tested using PCR for the presence of genes encoding toxins A and B. One hundred and thirty-three isolates of C. difficile from dogs (n = 92), horses (n = 21) and humans (n = 20), plus one each from a cat and a calf, were evaluated. Overall, 23 ribotypes were identified. Of these, nine were identified from...
Venezuelan equine encephalitis virus, southern Mexico. Equine epizootics of Venezuelan equine encephalitis (VEE) occurred in the southern Mexican states of Chiapas in 1993 and Oaxaca in 1996. To assess the impact of continuing circulation of VEE virus (VEEV) on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in Chiapas State. Human serosurveys and risk analyses indicated that long-term endemic transmission of VEEV occurred among villages with seroprevalence levels of 18% to 75% and that medical personnel had a high risk for VEEV exposure. Seroprevalence in wild animals suggested cotton rats as pos...
Genetic clustering of Borna disease virus natural animal isolates, laboratory and vaccine strains strongly reflects their regional geographical origin. The aim of this study was to gain more detailed insights into the genetic evolution and variability of Borna disease virus (BDV). Phylogenetic analyses were performed on field viruses originating from naturally infected animals, the BDV vaccine strain 'Dessau', four widely used laboratory strains and the novel BDV subtype No/98. Four regions of the BDV genome were analysed: the complete p40, p10 and p24 genes and the 5'-untranslated region of the X/P transcript. BDV isolates from the same geographical area exhibited a clearly higher degree of identity to each other than to BDV isolates from ot...
Comparison of HIV-1 and EIAV-based lentiviral vectors in corneal transduction. In this study we compare the ability of self-inactivating Human Immunodeficiency Virus 1 (HIV-1) and Equine Infectious Anaemia Virus (EIAV)-based vectors to mediate gene transfer to rabbit and human corneas and to a murine corneal endothelial cell line. Both vectors were pseudotyped with vesicular stomatitis virus-G (VSV-G) envelope and contained marker transgenes under the control of an internal CMV promoter. For specificity of action, the heterologous promoter in the EIAV-vector was exchanged for an inducible E-Selectin promoter, previously shown to regulate gene-expression in a plasmid syst...
West Nile virus in the vertebrate world. West Nile virus (WNV), an arthropod-borne virus belonging to the family Flaviviridae, had been recognized in Africa, Asia and the south of Europe for many decades. Only recently, it has been associated with an increasing number of outbreaks of encephalitis in humans and equines as well as an increasing number of infections in vertebrates of a wide variety of species. In this article, the data available on the incidence of WNV in vertebrates are reviewed. Moreover, the role of vertebrates in the transmission of WNV, the control of WNV infections in veterinary medicine as well as future perspect...
Preparation of recombinant African horse sickness virus VP7 antigen via a simple method and validation of a VP7-based indirect ELISA for the detection of group-specific IgG antibodies in horse sera. This paper describes the production and purification of a group-specific recombinant protein VP7 of African horse sickness virus serotype 3 (AHSV-3) and validation of an I-ELISA for the detection of IgG-antibodies to VP7 in horse sera. Baculovirus-expressed VP7 crystals were purified from infected insect cells. Analytical accuracy of the I-ELISA was examined using sera (n = 38) from an experimentally infected horse, from foals born to vaccinated mares, from guinea-pigs immunized with nine serotypes of AHSV, and from sera of animals infected with other orbiviruses. Compared to traditional serol...
Semi-nested PCR for the specific detection of Habronema microstoma or Habronema muscae DNA in horse faeces. Habronema microstoma and Habronema muscae (Spirurida: Habronematidae) are parasitic nematodes which infect the stomach and/or skin of equids. The accurate diagnosis of gastric habronemosis is central to studying its epidemiology, but data on its distribution and prevalence are lacking, mainly due to the limitations of clinical and coprological diagnosis in live horses. To overcome this constraint, a two-step, semi-nested PCR-based assay was validated (utilizing genetic markers in the nuclear ribosomal DNA) for the specific amplification of H. microstoma or H. muscae DNA from the faeces from ho...
Evaluation of administration of West Nile virus vaccine to pregnant broodmares. To determine whether administration of killed West Nile virus vaccine was associated with pregnancy loss among broodmares. Methods: Retrospective cohort study. Methods: 595 mares. Methods: Records of pregnant mares with known vaccination history from 4 farms were reviewed. Information obtained from 595 mares included mare's identification; farm; age; breed; reproductive status; last breeding date; date last known pregnant; vaccination date; age of conceptus at vaccination; vaccination during the early embryonic, early fetal, and late fetal periods; and whether an early embryonic death (EED), e...
Vector competence of Culicoides species and the seroprevalence of homologous neutralizing antibody in horses for six serotypes of equine encephalosis virus (EEV) in South Africa. Field-collected Culicoides species (Diptera: Ceratopogonidae) were fed on horse blood-virus mixtures containing one of the six serotypes of equine encephalosis virus (EEV1 to EEV6). The virus mean titres in the bloodmeals varied between 6.1 and 7.0 log10TCID50/mL. Of 19 Culicoides species assayed after 10 days extrinsic incubation at 23.5 degrees C, five yielded the challenge virus, namely Culicoides (Avaritia) imicola Kieffer (EEV1-6), C. (A.) bolitinos Meiswinkel (EEV1, 2, 4, 6), C. (Meijerehelea) leucostictus Kiefer (EEV1, 2), C. (Culicoides) magnus Colaço (EEV1) and C. (Hoffmania) zuluens...
Identification of another B-cell epitope in the type-specific region of equine herpesvirus 4 glycoprotein G. Recently, a novel 12-mer B-cell epitope, MKNNPIYSEGSL, in the type-specific region of equine herpesvirus 1 (EHV-1) glycoprotein G (gG) was identified and used as an antigen for enzyme-linked immunosorbent assay (Maeda et al., J. Clin. Microbiol. 42:1095-1098, 2004). Although our prototype strain, TH20p, possesses two repeat sequences containing the B-cell epitope, the EHV-4 NS80567 strain has two repeat sequences that are not identical. One repeat sequence stretch contained the B-cell epitope, while the other contained the 11-mer, MKNNPVYSESL (underlining indicates a different amino acid). In ...
Immunoglobulin M-capture enzyme-linked immunosorbent assay testing of cerebrospinal fluid and serum from horses exposed to west nile virus by vaccination or natural infection. The West Nile (WN) virus, present in the United States since 1999, is a cause of encephalomyelitis in birds, alligators, humans, and horses. No data exist regarding detection of anti-WN virus immunoglobins in equine cerebrospinal fluid (CSF). The aims of this study were to evaluate the blood-brain barrier (BBB) in WN virus-infected (WNE) horses, to compare diagnostic testing in serum and CSF, and to describe the immunoglobulin M (IgM) response in serum and CSF of vaccinated horses. CSF was collected from the lumbosacral (LS) space (n = 13) or the allanto-occipital (AO) space (n = 14) of WNE ho...
Molecular epidemiologic features of Corynebacterium pseudotuberculosis isolated from horses. To characterize isolates of Corynebacterium pseudotuberculosis from horses, cattle, and sheep in Colorado, Kentucky, Utah, and California in samples collected during perceived epidemics of infection (increased numbers of cases identified) in 2002 and 2003, and determine how closely isolates were related and their possible source. Methods: 54 isolates of C pseudotuberculosis from 49 horses, 4 cattle, and 1 sheep. Methods: Random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) assay, PCR assay for the gene encoding the phospholipase D (PLD) toxin, biochemical analyses, and tests...
