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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.
Detection of Trichinella spiralis in a horse during routine examination in Italy. Routine examination for Trichinella infection by artificial digestion of 5-g samples of muscle tissue revealed the presence of muscle larvae in one out of 28 horses imported from Romania to an abattoir in Italy. The parasite, identified as Trichinella spiralis by the polymerase chain reaction, showed a reproductive capacity index of 68 in Swiss mice. Light microscope examination of 200 nurse cell-larva complexes showed that 22% of them were calcified and that the capsules of the non-calcified nurse cells were 17.5-27.5 microns (s = 22.67 microns) thick and had very few cellular infiltrates. Th...
Strains of Actinobacillus spp. from diseases of animals and ostriches in Zimbabwe. Among the Actinobacillus spp. only A. lignieresii represents a homogenous and well studied taxon. However, haemolytic and non-haemolytic strains of A. equuli and A. suis are also isolated from a wide range of diseases in a variety of hosts. These isolates often pose problems in definitive identification. Consequently, several studies have been published, emphasizing the need for detailed studies to reclassify various members of this genus and also to assess their disease significance. We isolated 48 strains of Actinobacillus from clinical cases in horses, cattle, sheep, cat, pigs and ostrich. ...
Ocular tuberculosis in a horse. This paper is the first report of systemic tuberculosis involving the eyes in a horse. The animal lost condition and gradually became increasingly blind in both eyes; it was eventually euthanased. The pathological findings included bilateral, mycobacterial granulomatous uveitis with unilateral retinal detachment and necrosis, and disseminated, mycobacterial granulomatous foci in the myocardium, lungs, bronchial lymph nodes, kidneys, liver, pancreas, colon and visceral serosal surfaces, with the most extensive lesions in the myocardium. The mycobacteria were identified as Mycobacterium avium.
Association of deficiency in antibody response to vaccine and heterogeneity of Ehrlichia risticii strains with Potomac horse fever vaccine failure in horses. Ehrlichia risticii is the causative agent of Potomac horse fever (PHF), which continues to be an important disease of horses. Commercial inactivated whole-cell vaccines are regularly used for immunization of horses against the disease. However, PHF is occurring in large numbers of horses in spite of vaccination. In a limited study, 43 confirmed cases of PHF occurred between the 1994 and 1996 seasons; of these, 38 (89%) were in horses that had been vaccinated for the respective season, thereby clearly indicating vaccine failure. A field study of horses vaccinated with two PHF vaccines indicated...
Biological control of gastro-intestinal nematodes–facts, future, or fiction? The potential of using fungi to prevent nematodosis caused by parasites with free-living larval stages is well documented today. In this respect Duddingtonia flagrans, a net-trapping, nematode-destroying fungus, appears to be the most promising candidate. Laboratory experiments and in-vivo studies, where fungal spores have survived passage through the gastro-intestinal tract of cattle and horses, plus field studies with cattle, horses and pigs, demonstrate significant reduction in the number of infective larvae that develop in the faecal environment. In field trials this reduction subsequently...
Neonatal alloimmune thrombocytopenia in a quarter horse foal. Neonatal alloimmune thrombocytopenia is recognized as a spontaneous disease of human infants, piglets, and possibly mules, but it has not been previously reported in horses. A 1-day-old Quarter Horse foal presented to Michigan State University Large Animal Clinic with severe thrombocytopenia of unknown origin. Immunoglobulins that bound to the foal's platelets were identified in the mare's plasma, serum, and milk by indirect assays. The immunoglobulins were further shown to recognize platelets from the foal's full brother, born 1 year earlier. These findings, coupled with the clinical course o...
Elevation of cytokines associated with the thrombocytopenia of equine infectious anaemia. Thrombocytopenia is a common finding in infection with equine infectious anaemia virus (EIAV), a lentivirus with some homology to human immunodeficiency virus (HIV). The thrombocytopenia of EIA, like that in some HIV patients, appears to have a multifactorial pathogenesis. To investigate the decreased platelet production seen in experimental EIA, the levels of three potential negative regulators of platelet production--tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and interferon-alpha (IFN-alpha)--were measured in serum and bone marrow of six severe combi...
Fourier-transform infrared spectroscopic studies on the coordination of the side-chain COO- groups to Ca2+ in equine lysozyme. Interactions between Ca2+ and the Asp side chains in the Ca2+-binding site of equine lysozyme were investigated by Fourier-transform infrared (FT-IR) spectroscopy. In the spectrum of equine lysozyme, the intensities of the bands at about 1595 cm-1 and 1578 cm-1 in the region of the COO antisymmetric stretches increased upon Ca2+ binding. In the region of the COO- symmetric stretches, the loss of intensity at about 1388 cm-1 and gains of intensities at about 1423 cm-1 and 1403 cm-1 were observed due to Ca2+ binding to equine lysozyme. The spectral changes for equine lysozyme indicate that the C...
The use of Baypamun N in crowding associated infectious respiratory disease: efficacy of Baypamun N (freeze dried product) in 4-10 month old horses. The efficacy of an immunomodulator, Baypamun N, was tested in 4-10-month-old horses which were exposed to stress by weaning, transport and commingling with yearlings from different breeders (crowding). Verum (n = 26) and placebo animals (n = 27) received three intramuscular injections of the investigational preparations (days 0, 2, 9) starting at the day of commingling in one stable. The incidence of acute respiratory disease was high during the first 4 weeks after commingling. Approximately 50% of all horses showed seroconversion due to field infection by EHV1 and EHV4 during the observation ...
Isolation of virulent Rhodococcus equi from transtracheal aspirates of foals serodiagnosed by enzyme-linked immunosorbent assay. Although isolation of Rhodococcus equi from tracheobronchial aspirates is thought to be a definitive diagnosis of R. equi pneumonia in foals, virulence of isolates from the aspirates of infected foals remains obscure. In the present study, transtracheal aspirates were collected from thirty-one 1- to 6-month-old foals, which showed clinical signs of respiratory tract infection, and R. equi isolates were analyzed for the presence of virulence plasmids and virulence-associated antigens. Moreover, this method was compared with a serodiagnosis by an enzyme-linked immunosorbent assay (ELISA) to eval...
Genetic variation of envelope gp90 gene of equine infectious anemia virus isolated from an experimentally infected horse. Six strains of equine infectious anemia virus (EIAV) were recovered from febrile and non-febrile stages of a horse experimentally infected with the P337-V70 strain given once to a horse. The env gp90 genes of the isolates, the P337-V70 and P337-V26, avirulent virus derived from the P337-V70 strain, were sequenced. A comparison of the gp90 gene sequences revealed that amino acid variations among the viruses tested showed as high as 8.2 to 11.5%. In addition, the comparison also indicated that the isolates that recovered from the non-febrile stage were contained in nucleotide insertions in the p...
In vivo evaluation of intramedullary interlocking nail fixation of transverse femoral osteotomies in foals. To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals. Methods: A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. Methods: Six foals weighing 149 to 207 kg. Methods: The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5-in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all ...
Venereal infection of mares by equine arteritis virus and use of killed vaccine against the infection. Venereal infection with equine arteritis virus (EAV) was established in each of seven mares by inoculation via the cervix with 20 ml of viral suspension (> or = 8 x 10(6) plaque-forming units; PFU), following treatment with prostaglandin and oestradiol. A dose of < or = 8 x 10(5) PFU produced infection in only five of eight mares. Serum neutralizing antibody developed in mares manifesting clinical signs of equine viral arteritis (EVA), and a weak antibody was detectable in one apparently healthy mare inoculated with 8 x 10(5) PFU. Virus isolation was demonstrated not only in the buffy co...
A novel P/V/C gene in a new member of the Paramyxoviridae family, which causes lethal infection in humans, horses, and other animals. In 1994, a new member of the family Paramyxoviridae isolated from fatal cases of respiratory disease in horses and humans was shown to be distantly related to morbilliviruses and provisionally called equine morbillivirus (K. Murray et al., Science 268:94-97, 1995). To facilitate characterization and classification, the virus was purified, viral proteins were identified, and the P/V/C gene was cloned and sequenced. The coding strategy of the gene is similar to that of Sendai and measles viruses, members of the Paramyxovirus and Morbillivirus genera, respectively, in the subfamily Paramyxovirina...
Pathogenesis and clinical signs of equine herpesvirus-1 in experimentally infected ponies in vivo. Equine herpesvirus-1 (EHV-1) causes respiratory disease, neonatal death, abortion and neurologic disease. The main purpose of this study was to identify viral antigen in respiratory tract samples by immunoperoxidase staining. Six pony foals were selected on the basis of demonstrating seronegativity to EHV-1 by virus neutralization and housed in isolation. They were infected experimentally by administering EHV-1 nebulized ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals had febrile responses, nasal discharge, and enlarged submandibular lymph ...
An outbreak of foal yersiniosis in Poland: pathological and bacteriological examination. In the springtime of 1995, 10 per cent of foals at a stud-farm died due to suppurative lesions. Three dead foals were examined. The manifestations of watery diarrhoea and pneumonia were observed. A profuse growth of an enterotoxigenic strain of Yersinia pseudotuberculosis was obtained from the internal organs of the foals. The foals with clinical symptoms of pneumonia and watery diarrhoea were immunized with Propionibacterium acnes t. II. All mares and their offspring from the stud were treated with an immunomodulator (Propionibacterium acnes t. II) and then vaccinated with a formalin-inactiva...
Fructosamine measurement in ponies: validation and response following experimental cyathostome infection. Validation of an assay for measurement of fructosamine in equine serum and plasma utilised blood samples collected from 24 British native breed ponies. The results indicated that fructosamine can be measured easily using an assay which is precise and accurate. Paired plasma and serum fructosamine measurements were highly correlated, however, greater variations were observed within serum compared with those in plasma. A reference range for fructosamine in plasma was calculated to be 256.9 +/- 60.6 mumol litre-1 (mean +/- 2 SD). In order to assess the fructosamine response following experimental...
Expression cloning and humoral immune response to the nucleocapsid and membrane proteins of equine arteritis virus. To provide a convenient and sensitive method for the detection of equine arteritis virus (EAV)-specific serum antibodies, we developed an immunoblot assay employing the EAV nucleocapsid (N) and membrane (M) proteins expressed in a procaryotic expression vector (pMAL-c2) for the production of recombinant maltose-binding (MBP) fusion proteins (MBP-N and MBP-M). The antigenic reactivity of the recombinant fusion proteins and their Xa factor cleavage EAV products was confirmed by immunoblot using horse antisera to EAV. Some horse sera, however, showed immune reactivity to the MBP fusion partner pr...
Immunodiagnosis of fasciolosis in horses and pigs using western blots. Crude and partially purified somatic (S) and excretory-secretory (ES) antigens of Fasciola hepatica were subjected to Western blot analysis in order to identify polypeptides that would enable specific and sensitive immunodiagnosis of horse and pig fasciolosis to be undertaken. Sera from 20 horses and 20 pigs with natural infections of F. hepatica and the same number of uninfected hosts of each species were tested, together with sera from 2 pigs with Cysticercus cellulosae infections. Using crude S antigens, sera from infected horses and pigs reacted specifically with a wide range of polypeptid...
Outbreak of Salmonella infantis infection in a large animal veterinary teaching hospital. During the past 11 years, there have been numerous reports of outbreaks of salmonellosis involving horses in veterinary teaching hospitals. Some of these outbreaks have been associated with Salmonella serotypes not commonly associated with infection of horses. Salmonella infantis is among the more common Salmonella serotypes isolated from human beings, and is an important pathogen in the broiler chicken industry. However, it was not commonly isolated from horses or cattle on a national basis between 1993 and 1995. In this report, we describe an outbreak of S infantis infection among large anim...
Abscess on the lateral epicondyle of the humerus as a cause of lameness in a horse. An 18-month-old 450-kg [990-lb] sexually intact male Holsteiner was evaluated for lameness of the left forelimb of 3-months' duration. We were unable to localize the site of lameness, using intra-articular and perineural anesthesia, and radiography of the shoulder and cubital joint (elbow) did not reveal radiographic abnormalities. Nuclear scintigraphy was performed. An increase in radio-isotope uptake was evident at the lateral epicondyle of the left humerus. Radiographs of the region 3 weeks later revealed a 1.5-cm focal lucency surrounded by a 1.0-cm rim of necrotic bone. The lesion was con...
Characterisation of gamma herpesviruses in the horse by PCR. A polymerase chain reaction (PCR) based on a combination of oligonucleotide primers selected using the octamer frequency disparity method with primers specific for EHV-5 (described by other authors) recognized all of a series of gamma herpesvirus field isolates. This PCR produced only three fragments: (1) one EHV-2-specific; (2) one EHV-5-specific; and (3) a fragment that occurred alone or in combination with the other two. Cloning and sequencing of four different isolates yielding only the last PCR product showed that this corresponds to a deletion/insertion mutant of EHV-2. The fact that thi...
Expression of transforming growth factor-beta 1 in normal and dyschondroplastic articular growth cartilage of the young horse. This study describes the distribution pattern of transforming growth factor-beta 1 (TGF-beta 1) mRNA and protein in normal pre- and post natal growth cartilage and alterations present in lesions of dyschondroplasia (osteochondrosis). TGF-beta 1 expression and immunoreactivity have been investigated by in situ hybridisation and immunolocalisation in the articular/epiphyseal growth cartilage of the lateral trochlear ridge of the distal femur. Cartilage was obtained from 19 normal Thoroughbred horses (5 prenatal and 14 post natal horses) and 15 post natal horses with dyschondroplasia (DCP). TGF-b...
Frequency of memory cytotoxic T lymphocytes to equine infectious anemia virus proteins in blood from carrier horses. Horses with equine infectious anemia virus (EIAV) have episodes of viremia and disease; however, most eventually become inapparent carriers. A possible mechanism of control is cytotoxic T lymphocytes (CTL). To evaluate CTL in inapparent carriers with low viral loads, peripheral blood mononuclear cells (PBMC) were stimulated in vitro with autologous EIAV-infected PBMC and human IL-2 to detect memory CTL (CTLm). In initial studies, three carriers had CTLm and one of these had low-level effector CTL (CTLe). The CTLm were restricted by equine lymphocyte alloantigen-A (ELA-A) locus encoded MHC clas...
Clinical trial of moxidectin oral gel in horses. A clinical trial carried out over 98 days was done to evaluate treatment of horses with moxidectin gel for efficacy as measured by (1) reduction in the production of parasite ova post treatment, (2) a comparison of the posttreatment parasite egg count suppression of moxidectin to ivermectin, and (3) assessment of the field safety, animal acceptance of the moxidectin formulation, and the utility of the moxidectin delivery device. One hundred and fifty Standardbred horses with naturally acquired parasite infections were used in the study. Moxidectin had more prolonged and greater suppressive inf...
Infection of bone marrow macrophages by equine infectious anemia virus. To characterize infection of bone marrow-derived macrophages (BMDM) with equine infectious anemia virus (EIAV) by determining virus production, effects on viability, and induction of cytokines. Methods: BMDM obtained from bone marrow of 6 clinically normal adult horses. Methods: BMDM were infected with EIAV at a multiplicity of infection of 8. Cell viability, percentage of cells with detectable viral protein, reverse transcriptase activity, and concentrations of infective virus (focus-forming units/ml), interleukin 6, and tumor necrosis factor-alpha were measured in culture supernatant samples...
Immunohistochemical demonstration of African horse sickness viral antigen in formalin-fixed equine tissues. The distribution of viral antigen was studied in various tissues of three ponies, aged 3-4 years, infected experimentally with a virulent strain of African horse sickness virus (AHSV) serotype 4. Tissues were collected from the animals in the terminal stage of the peracute form of the disease and from one noninfected horse, included as a control. A polyclonal antibody with specificity for AHSV, plus the nonstructural protein NS2, was used in a sensitive avidin-biotin-peroxidase-complex (ABC) method performed on formalin-fixed, paraffin-embedded tissue sections. AHSV antigen was located primari...
Antibodies against equine herpesviruses in free-ranging mountain zebras from Namibia. Twenty-one blood samples of free-ranging mountain zebras (Equus zebra) from Namibia were tested for equine herpesvirus (EHV-1, -2, -3, -4) specific antibodies by immunofluorescence assay (IFA) and neutralization test (NT). Additionally, type-specific nested polymerase chain reactions (nested PCR) were employed for detection of EHV-1, -2 and -4 DNA. Equine herpesvirus-1 antibodies were detected by IFA in all zebras, while only seven serum samples contained EHV-4 IFA antibodies. Sera with high IFA antibodies also were found to neutralize EHV-1 and -4. Furthermore, 20 zebras were EHV-2 seropositi...
Evaluation of a test for identification of Arabian horses heterozygous for the severe combined immunodeficiency trait. To determine whether a recently developed test would correctly identify horses heterozygous for the severe combined immunodeficiency (SCID) trait. Methods: Case series. Methods: 17 healthy Arabian horses that had previously produced foals with SCID, 1 healthy Arabian foal whose dam and sire had produced foals with SCID, 4 foals with SCID, and 1 healthy non-Arabian foal. Methods: DNA was extracted from leukocytes or fibroblasts, amplified by means of polymerase chain reaction, and hybridized with probes specific for the normal and mutant alleles of the catalytic subunit of DNA-dependent protein...
