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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.
Antibody and IFN-gamma responses induced by a recombinant canarypox vaccine and challenge infection with equine influenza virus. In horses, equine influenza virus (EIV) is a leading cause of respiratory disease. Conventional inactivated vaccines induce a short-lived immune response. By comparison, natural infection confers a long-term immunity to re-infection. An aim of new equine influenza vaccines is to more closely mimic natural infection in order to achieve a better quality of immunity. A new live recombinant vaccine derived from the canarypox virus vector and expressing haemagglutinin genes of EIV (subtype H3N8) has been developed. Stimulation of the immune system was studied after immunisation with this canarypox-...
Haycocknema-like nematodes in muscle fibres of a horse. A 14-year-old horse (imported to Switzerland from Ireland 8 years earlier) showed signs of chewing muscle atrophy. A severe chronic myositis, caused by numerous immature and mature female nematodes, was diagnosed in muscle samples obtained by biopsy and subsequently at necropsy. Most of the nematodes had invaded muscle fibres of the masseter, root of the tongue and anterior breast, only a few were found in the intermuscular interstitium. Isolated nematodes and parasite sections were clearly different from muscle larvae of Trichinella spp. but showed morphological similarities to Haycocknema pe...
Guttural pouch mycosis in a 6-month-old filly. A 6-month-old filly was presented with unilateral epistaxis. Based on clinical signs, endoscopic examination, and postmortem examination, guttural pouch mycosis was diagnosed. The young age of the filly and the fact that this was the 2nd diagnosis of guttural pouch mycosis on this farm was unusual. Mycose de la poche gutturale chez une pouliche de 6 mois. Une pouliche âgée de 6 mois a été présentée pour épistaxis unilatérale. En tenant compte des signes cliniques, de l’examen endoscopique et de l’examen post-mortem, un diagnostic de mycose de la poche gutturale a été posé. Le je...
Molecular typing of VapA-positive Rhodococcus equi isolates from Jeju native horses, Korea. We recently demonstrated the presence of virulence-associated protein antigen (VapA)-positive Rhodococcus equi in Jeju Island, Korea. These bacteria contained one of two distinct plasmid types, a 90-kb type II plasmid, which has been found in isolates from the native Kiso horses of Japan, and a new variant, a 90-kb type V plasmid. However, the genotypic characters of the VapA-positive R. equi from Jeju native horses and their environments are poorly understood. Ninety-eight isolates from soil samples and 89 isolates from fecal samples were collected from five farms that breed or have bred Jeju...
Comparison of four staining methods for detection of mast cells in equine bronchoalveolar lavage fluid. Mast cells normally are present in equine bronchoalveolar lavage fluid (BALF), but usually represent <2% of all cells in healthy horses. An increased percentage of mast cells has been associated with airway hyperactivity and inflammatory airway diseases, but marked differences are reported between studies in normal and diseased horses. Because an abnormal mast cell count may be of clinical relevance, we compared the ability of a fast Romanowsky method to stain mast cell granules with that of 3 metachromatic stains: automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. The B...
Potential role of Clostridium difficile as a cause of duodenitis-proximal jejunitis in horses. Duodenitis-proximal jejunitis (DPJ) is an idiopathic condition in the horse characterized by inflammation and oedema of the duodenum and proximal jejunum. Clinical signs include colic, ileus, depression, fluid accumulation in the small intestine and stomach, and endotoxaemia. The objective of this study was to investigate prospectively the role of Clostridium difficile in this idiopathic disease. Nasogastric reflux from 10 consecutive cases with DPJ and 16 consecutive horses with other causes of nasogastric reflux was cultured for C. difficile, other Clostridium spp., and Salmonella. Toxigenic...
Development and evaluation of a Sarcocystis neurona-specific IgM capture enzyme-linked immunosorbent assay. Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses caused primarily by the protozoal parasite Sarcocystis neurona. Currently available antemortem diagnostic testing has low specificity. The hypothesis of this study was that serum and cerebrospinal fluid (CSF) of horses experimentally challenged with S neurona would have an increased S neurona-specific IgM (Sn-IgM) concentration after infection, as determined by an IgM capture enzyme linked immunoassay (ELISA). The ELISA was based on the S neurona low molecular weight protein SNUCD-1 antigen and the monoclonal an...
Malassezia species isolated from the intermammary and preputial fossa areas of horses. Malassezia-type yeasts previously have been observed on cytologic examination of the intermammary region of mares that presented with tail-head pruritus; topical antiyeast treatment resolved the pruritus. Further, Malassezia dermatitis has been observed in horses in intertriginous areas such as the udder and prepuce; the species of yeast was not confirmed. It is not known whether healthy mares or male horses can be carriers of this yeast in these body areas. Objective: Malassezia spp. are present in the intermammary region in healthy mares and the preputial fossa in healthy geldings. Methods: ...
Usefulness of a commercial equine IgG test and serum protein concentration as indicators of failure of transfer of passive immunity in hospitalized foals. Detection of failure of transfer of passive immunity (FTPI) is important in reducing morbidity and mortality in neonatal foals. We investigated the performance of a commercial equine IgG test (SNAP Foal IgG Test Kit) to diagnose FTPI in hospitalized foals. Furthermore, we evaluated the usefulness of serum total protein (STP) and serum globulin (SG) concentrations as indicators of FTPI. Serum IgG concentration was measured by means of the SNAP test and single radial immunodiffusion, and SG and STP concentrations were determined by means of a clinical chemistry analyzer. Subjects were 67 hospita...
Evaluation of the effects of footwear hygiene protocols on nonspecific bacterial contamination of floor surfaces in an equine hospital. To evaluate the effects of footwear hygiene protocols on bacterial contamination of floor surfaces in an equine hospital. Methods: Field trial. Methods: Footwear hygiene protocols evaluated included use of rubber overboots with footbaths and footmats containing a quaternary ammonium disinfectant, rubber overboots with footbaths and footmats containing a peroxygen disinfectant, and no restrictions on footwear type but mandatory use of footbaths and footmats containing a peroxygen disinfectant. Nonspecific aerobic bacterial counts were determined via 2 procedures for sample collection and bacter...
Use of DNA and recombinant canarypox viral (ALVAC) vectors for equine herpes virus vaccination. In this study, experimental canarypox virus (ALVAC) and plasmid DNA recombinant vaccines expressing the gB, gC and gD glycoproteins of EHV-1 were assessed for their ability to protect conventional ponies against a respiratory challenge with EHV-1. In addition, potential means of enhancing serological responses in horses to ALVAC and DNA vaccination were explored. These included co-administration of the antigen with conventional adjuvants, complexation with DMRIE-DOPE and co-expression of the antigen along with equine GM-CSF. Groups of EHV primed ponies were vaccinated twice intra-muscularly wi...
Characterization of an equine mannose-binding lectin and its roles in disease. The mannose-binding lectin (MBL), a pattern recognition serum protein, participates in the innate immune system of mammals as an opsonin. In humans, MBL plays a key role in first-line host defense against infection during the lag period prior to the development of a specific immune response. MBL also activates complement via the lectin pathway that requires a MBL-associated serine protease-2 (MASP-2). Homologues of human MBL (hMBL) have been identified in a variety of mammals, fish, and primitive animals such as ascidians. In this study, we report that equine MBL (eMBL) has properties that are...
Antibody and cellular immune responses following DNA vaccination and EHV-1 infection of ponies. Equine herpesvirus-1 (EHV-1) is the cause of serious disease with high economic impact on the horse industry, as outbreaks of EHV-1 disease occur every year despite the frequent use of vaccines. Cytotoxic T-lymphocytes (CTLs) are important for protection from primary and reactivating latent EHV-1 infection. DNA vaccination is a powerful technique for stimulating CTLs, and the aim of this study was to assess antibody and cellular immune responses and protection resulting from DNA vaccination of ponies with combinations of EHV-1 genes. Fifteen ponies were divided into three groups of five ponies...
Immune response to Sarcocystis neurona infection in naturally infected horses with equine protozoal myeloencephalitis. Equine protozoal myeloencephalitis (EPM) is one of the most common neurologic diseases of horses in the United States. The primary etiologic agent is Sarcocystis neurona. Currently, there is limited knowledge regarding the protective or pathophysiologic immune response to S. neurona infection or the subsequent development of EPM. The objectives of this study were to determine whether S. neurona infected horses with clinical signs of EPM had altered or suppressed immune responses compared to neurologically normal horses and if blood sample storage would influence these findings. Twenty clinical...
Passive immunotherapy for influenza A H5N1 virus infection with equine hyperimmune globulin F(ab’)2 in mice. Avian influenza virus H5N1 has demonstrated considerable pandemic potential. Currently, no effective vaccines for H5N1 infection are available, so passive immunotherapy may be an alternative strategy. To investigate the possible therapeutic effect of antibody against highly pathogenic H5N1 virus on a mammal host, we prepared specific equine anti-H5N1 IgGs from horses vaccinated with inactivated H5N1 virus, and then obtained the F(ab')2 fragments by pepsin digestion of IgGs. Methods: The horses were vaccinated with inactivated H5N1 vaccine to prepare anti-H5N1 IgGs. The F(ab')2 fragments were p...
Cerebral listeriosis in an adult Freiberger gelding. 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...
Increased presence of T lymphocytes in central nervous system of EPM affected horses. Equine protozoal myeloencephalitis (EPM), caused by Sarcocystis neurona infection in the central nervous system (CNS), affects up to 1% of all horses during their lifetimes. Neither the protective immune response nor the immunopathology associated with the disease is well understood. To begin to clarify the pathogenesis of the disease, immunohistochemical staining for B and T lymphocytes was performed on spinal cord sections obtained from 17 horses, all of which were all positive for S. neurona based on immunohistochemical staining. Fifteen of the 17 horses included in the study were killed du...
Inflammatory aural polyp in a horse. An inflammatory aural polyp was identified in a 1-year-old standardbred filly, which presented with otorrhea and head rubbing. The polyp was removed by traction-avulsion, and the filly showed no subsequent signs of otorrhea. Aural polyps have not been reported in horses, but they are commonly seen in companion animals and humans. Un polype auditif inflammatoire a été identifié chez une pouliche Standardbred d’un an présentée pour otorrhée et frottage de tête. Le polype a été retiré par traction-avulsion et la pouliche n’a pas manifesté de signes subséquents d’otorrhée. Les ...
Factors associated with failure of thoroughbred horses to train and race. The low productivity associated with training and racing of young Thoroughbreds (TBs) in the UK due to athletic inability, injury and disease requires further study. Objective: To identify the time points and causes of losses during growth and training phases of a cohort of 1022 TB foals born in 1999 up to the end of their third year. Methods: Movement and fate of 1022 Thoroughbred foals conceived in 1998 and born live in 1999 were monitored from birth to age 3 years. Those (n = 562) that entered training age 2 and/or 3 years with one of 161 registered trainers in Britain or Ireland in 2001/2 ...
Two cases of equine abortion caused by Rhodococcus equi. Rhodococcus equi was isolated from lung, liver, spleen, and stomach content of two aborted equine fetuses of 7 and 8 months gestation from two different farms. Lesions included diffuse pyogranulomatous pneumonia with numerous Gram-positive coccobacilli within the cytoplasm of macrophages, multinucleated Langhans giant cells and neutrophils, and enhanced extramedullary hematopoiesis with megakaryocytosis within the liver and spleen. Detection of R. equi was made by bacteriology and immunohistochemistry for R. equi and VapA, the virulence factor of R. equi. R. equi and VapA were identified withi...
Dose-confirmation studies of the cestocidal activity of pyrantel pamoate paste in horses. Dose confirmation studies of the cestocidal activity of pyrantel pamoate paste were conducted at two sites in North America during 2001. Horses with naturally-acquired cestode infections were identified by detection of typical Anoplocephala spp. eggs in feces collected between 7 and 92 days prior to treatment. Twenty and 22 horses were enrolled at Site 1 (Urbana, IL) and Site 2 (Knoxville, TN), respectively. Candidate horses were acclimated to study conditions for 14 days, ranked by length of interval since coprologic confirmation, and allocated randomly to one of two treatment groups: (T1) py...
Investigation of equine influenza cases exhibiting neurological disease: coincidence or association? Equine influenza is usually a transient and self-limiting disease. However, during an outbreak of equine influenza in the UK in 2003 there were reports of unusually severe clinical signs among unvaccinated animals. Two influenza-infected horses developed neurological signs, and one was subjected to euthanasia. Post-mortem examination of the brain revealed viral-type non-suppurative encephalitis, and influenza virus antigen was demonstrated by immunolabelling of sections of nasal mucosa. A syndrome known as influenza-associated encephalopathy has been described in man. Although not proved, the ...
Survey on the subject of equine Lyme borreliosis. According to the results of a questionnaire on equine Lyme borreliosis addressing veterinarians in Germany, the existence of the disease was confirmed by more than half of the 118 participants. Practitioners who regarded Borrelia burgdorferi as a pathogen of horses seemed to be more sensitized in terms of the number of annually diagnosed cases as well as the frequency of occurrence of tick infestation with equine patients or prophylactic treatments against ectoparasites by horse owners. Chronically poor performance and diverse orthopaedic problems were the clinical symptoms most often leading ...
The Fell pony immunodeficiency syndrome also occurs in the Netherlands: a review and six cases. Over the last ten years a fatal syndrome associated with immunodeficiency and severe anaemia has been reported in young Fell pony foals in the UK. Affected foals are usually normal at birth but from the age of 2-4 weeks they progressively lose condition and become severely anaemic. Signs of immunodeficiency become apparent at around 3-4 weeks of age. Morbidity is low but mortality is 100% despite intensive treatment. Affected foals die or are euthanized usually before they reach the age of 3 months. A single autosomal recessive gene is suggested to be on the basis of the syndrome. Recently, af...
Penetration of equine leukocytes by merozoites of Sarcocystis neurona. Horses are considered accidental hosts for Sarcocystis neurona and they often develop severe neurological disease when infected with this parasite. Schizont stages develop in the central nervous system (CNS) and cause the neurological lesions associated with equine protozoal myeloencephalitis. The present study was done to examine the ability of S. neurona merozoites to penetrate and develop in equine peripheral blood leukocytes. These infected host cells might serve as a possible transport mechanism into the CNS. S. neurona merozoites penetrated equine leukocytes within 5 min of co-culture. I...
Seroprevalences of Toxoplasma gondii and Neospora sp. infections in Swedish horses. Sera from 414 Swedish horses were investigated for the presence of antibodies to Toxoplasma gondii and Neospora sp. by the T. gondii direct agglutination test (DAT), and an Neospora caninum iscom-ELISA. Five sera (1%) had a titre >1:40 in DAT, but when analysed by immunoblotting against T. gondii antigens only two of them were positive, giving a seroprevalence of 0.5%. Since the Neospora iscom ELISA had not been validated for equine sera it was used for an initial screening, and all sera with an optical density exceeding 0.200 absorbance units were selected for further investigation by immu...
