Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Effect of eastern equine encephalomyelitis virus on the survival of Aedes albopictus, Anopheles quadrimaculatus, and Coquillettidia perturbans (Diptera: Culicidae). The effect of eastern equine encephalomyelitis (EEE) virus on the survivorship of Aedes albopictus (Skuse), Anopheles quadrimaculatus Say, and Coquillettidia perturbans (Walker) was determined experimentally. Female mosquitoes were allowed to feed on EEE viremic chicks, and survival rates were compared for infected and uninfected mosquitoes. Additionally, the survival of female Cq. perturbans and An. quadrimaculatus intrathoracically (i.t.) inoculated with EEE was compared with controls receiving diluent inoculations. Infection with EEE significantly reduced survival in Cq. perturbans compared...
Identification of lipoprotein homologues of pneumococcal PsaA in the equine pathogens Streptococcus equi and Streptococcus zooepidemicus. Streptococcus equi and Streptococcus zooepidemicus are major etiological agents of upper and lower airway disease in horses. Despite the considerable animal suffering and economic burden associated with these diseases, the factors that contribute to the virulence of these equine pathogens have not been extensively investigated. Here we demonstrate the presence of a homologue of the Streptococcus pneumoniae PsaA protein in both of these equine pathogens. Inhibition of signal peptide processing by the antibiotic globomycin confirmed the lipoprotein nature of the mature proteins, and surface expo...
Climate change: effects on culicoides–transmitted viruses and implications for the UK. Changes in the distribution and abundance of insects are likely to be amongst the most important and immediate effects of climate change. We review here the risk that climate change poses to the UK's livestock industry via effects on Culicoides biting midges, the vectors of several arboviruses, including those that cause bluetongue (BT) and African horse sickness (AHS). The major old-world vector of BT and AHS viruses, C. imicola, occurs in southern Europe and will spread further north as global temperatures increase. It is unlikely, however, that in the foreseeable future it will reach and be...
Efficient homologous RNA recombination and requirement for an open reading frame during replication of equine arteritis virus defective interfering RNAs. Equine arteritis virus (EAV), the prototype arterivirus, is an enveloped plus-strand RNA virus with a genome of approximately 13 kb. Based on similarities in genome organization and protein expression, the arteriviruses have recently been grouped together with the coronaviruses and toroviruses in the newly established order Nidovirales. Previously, we reported the construction of pEDI, a full-length cDNA copy of EAV DI-b, a natural defective interfering (DI) RNA of 5.6 kb (R. Molenkamp et al., J. Virol. 74:3156-3165, 2000). EDI RNA consists of three noncontiguous parts of the EAV genome fused ...
Pseudallescheria boydii infection of the nasal cavity of a horse. An 18-year-old 454-kg (1,000-lb) American Quarter Horse gelding was evaluated because of chronic intermittent malodorous right-sided nasal discharge. Endoscopy revealed a mycotic plaque in the nasal cavity adjacent to the nasomaxillary opening of the right caudal maxillary sinus. The nasomaxillary opening appeared to be larger than normal. Fungal culture of specimens of the mycotic plaque yielded Pseudallescheria boydii. The horse was treated with 2% miconazole intranasally, sodium iodide i.v., and potassium iodide p.o. Thirty and 60 days after treatment was initiated, the nasal cavity was fou...
Unilateral nondisseminated actinomycosis of the hydrocele wall: a case report of actinomycosis in the urogenital tract. Actinomycosis of the urogenital tract is rare and predominantly an infectious disease of horses, cattle, swine, and humans. This case report describes isolated actinomycosis of the hydrocele wall presenting as an inflamed right-sighted hydrocele.
Genomic variability of equine herpesvirus-5. Seventeen New Zealand isolates of equine herpesvirus 5 (EHV-5) were compared to the Australian prototype strain. PCR primers were designed to amplify EHV-5 glycoprotein B (gB) gene, and Restriction Fragment Length Polymorphism (RFLP) was used to detect differences between cloned PCR products. EHV-5 isolates from different horses showed a high degree of heterogeneity. However, EHV-5 isolates from individual horses remained homogeneous when examined over a period of time or isolated from different sites. A single EHV-5 gB RFLP profile was detected in isolates from each individual horse but one. ...
Secondary structure model for the ITS-2 precursor rRNA of strongyloid nematodes of equids: implications for phylogenetic inference. In order to maximise the positional homology in the primary sequence alignment of the second internal transcribed spacer for 30 species of equine strongyloid nematodes, the secondary structures of the precursor ribosomal RNA were predicted using an approach combining an energy minimisation method and comparative sequence analysis. The results indicated that a common secondary structure model of the second internal transcribed spacer of these nematodes was maintained despite significant interspecific differences (2-56%) in primary sequences. The secondary structure model was then used to refine...
[Equine Rhodococcus equi pneumonia: first report in Israel and its significance for man]. Rhodococcus equi is an important pathogen in young horses. In recent years it has been increasingly recognized as an opportunistic infectious agent in patients with immune deficiency. The increase in recognized cases may be related to the increased prevalence of AIDS. However, more cases may have been recognized lately due to increased awareness of the pathogenicity of this bacterium. Based on medical reports, there appears to be an association between Rhodococcus equi infections and exposure to animals, horses in particular. During the past year, 2 cases of rhodococcus pneumonia were diagnose...
Characterization of Escherichia coli isolated from adult horses with and without enteritis. In the present study E. coli strains isolated from the faeces of ten horses with diarrhoea and 14 horses without diarrhoea were characterized. All horses were culture negative for Salmonella species. Nine colonies of E. coli from each faecal sample were picked at random and a DNA fingerprint was made by means of a polymerase chain reaction (PCR) using Enterobacterial Repetitive Intergenic Consensus (ERIC) primers. The number of E. coli genotypes did not differ significantly between horses with and without diarrhoea. In addition, all E. coli strains with different DNA fingerprints were tested b...
Transmission of Ehrlichia risticii, the agent of Potomac horse fever, using naturally infected aquatic insects and helminth vectors: preliminary report. Ehrlichia risticii, the agent of Potomac horse fever (PHF), has been recently detected in trematode stages found in snail secretions and in aquatic insects. Based on these findings, horses could conceivably be exposed to E. risticii by skin penetration with infected cercariae, by ingestion of infected cercariae in water or via metacercariae in a second intermediate host, such as an aquatic insect. In order to test this hypothesis, horses were challenged with infectious snail secretions and aquatic insects collected from a PHF endemic region in northern California. Two horses stood with their f...
Determination of the activity of ponazuril against Sarcocystis neurona in cell cultures. The present study examined the efficacy of ponazuril in inhibiting merozoite production of Sarcocystis neurona in cell cultures. Ponazuril inhibited merozoite production by more that 90% in cultures of S. neurona treated with 1.0 microg/ml ponazuril and greater than 95% inhibition of merozoite production was observed when infected cultures were treated with 5.0 microg/ml ponazuril. Ponazuril may have promise as a therapeutic agent in the treatment of S. neurona induced equine protozoal myeloencephalitis (EPM) in horses.
Equine herpesvirus 1 (EHV-1) glycoprotein D DNA inoculation in horses with pre-existing EHV-1/EHV-4 antibody. We have shown previously that equine herpesvirus 1 (EHV-1) glycoprotein D (gD) DNA elicited protective immune responses against EHV-1 challenge in murine respiratory and abortion models of EHV-1 disease. In this study, 20 horses, all with pre-existing antibody to EHV-4 and two with pre-existing antibody to EHV-1, were inoculated intramuscularly with three doses each of 50, 200 or 500microg EHV-1 gD DNA or with 500microg vector DNA. In 8 of 15 horses, inoculation with EHV-1 gD DNA led to elevated gD-specific antibody and nine horses exhibited increased virus neutralising (VN) antibody titres co...
Application of a type-specific enzyme-linked immunosorbent assay for equine herpesvirus types 1 and 4 (EHV-1 and -4) to horse populations inoculated with inactivated EHV-1 vaccine. A type-specific enzyme-linked immunosorbent assay (ELISA) using equine herpesvirus types 1 (EHV-1) and 4 (EHV-4) glycoprotein G was applied for sero-epizootiology of EHV infections in Japan. Recently, an inactivated EHV-1 vaccine has been administered to racehorses for prevention of upper respiratory disease. To examine the effect of the vaccination on the result of the ELISA, 6 horses were experimentally inoculated three times intramuscularly or intranasally with inactivated EHV-1 vaccine. Sera collected from these horses were used to the type-specific ELISA and complement-fixation (CF) test....
Detection of biological threat agents by immunomagnetic microsphere-based solid phase fluorogenic- and electro-chemiluminescence. This article reviews the recent development of two solid-phase chemiluminescence-based techniques, fluorogenic-chemiluminescence (FCL) and electro-chemiluminescence (ECL) for detection of biological threat agents. Both techniques entail a labeled sandwich immunoassay. The objectives of this work are to develop advanced techniques for sensitive and effective detection of a target analyte, particularly in cases where the analysis includes complex samples containing multiple contaminating factors. Other important considerations in developing such detection techniques include the ease of use, the ...
An outbreak of type C botulism in 12 horses and a mule. A USDA Early Response Team investigated deaths of several horses and a mule in northern Arizona at the request of local animal health officials. Thirteen animals (12 horses and 1 mule) housed at 5 facilities in a 7.4 square mile area died between August 1998 and January 1999. Clinical signs consisted of muscular weakness that rapidly progressed to lateral recumbency. Ten animals had paresis of the tongue, throat, or lips. Affected animals appeared alert and were interested in eating and drinking, even while recumbent. All 13 animals were euthanatized. Clostridium botulinum type C was isolated ...
Mutations occurring during serial passage of Japanese equine infectious anemia virus in primary horse macrophages. An attenuated equine infectious anemia virus (EIAV), named V26, was previously obtained after 50 passages of the Japanese virulent strain V70 in primary macrophage culture. To clarify the differences between both viruses, their full-length sequences were determined. There were higher mutations in S2 (6.15% amino acid difference) and LTR (10.7% nucleotide difference). The presumed initiation codon of the S2 gene was absent from the sequence of V26. There was a large insertion within the long-terminal repeat (LTR) U3 hypervariable region of V26. In addition, there were minor mutations in gag (1....
Pathogenicity of Rhodococcus equi expressing a virulence-associated 20 kDa protein (VapB) in foals. Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoc...
The acute phase protein serum amyloid A (SAA) as an inflammatory marker in equine influenza virus infection. The acute phase protein serum amyloid A (SAA) has proven potentially useful as an inflammatory marker in the horse, but the knowledge of SAA responses in viral diseases is limited. The aim of this study was to evaluate SAA as a marker for acute equine influenza A2 (H3N8) virus infection. This is a highly contagious, serious condition that inflicts suffering on affected horses and predisposes them to secondary bacterial infections and impaired performance. Seventy horses, suffering from equine influenza, as verified by clinical signs and seroconversion, were sampled in the acute (the first 48 h...
Infection of aquatic insects with trematode metacercariae carrying Ehrlichia risticii, the cause of Potomac horse fever. We provide evidence of Ehrlichia risticii Holland, the agent of Potomac horse fever, in trematode stages found in aquatic insects collected from a pasture stream in northern California, using nested polymerase chain reaction (PCR) amplification and sequence analyses of the 16S rRNA, 51 kDa major antigen and groEL heat shock protein genes. E. risticii was detected in metacercariae found in the immatures and adults of the following insects: caddisflies (Trichoptera), mayflies (Ephemeroptera), damselflies (Odonata, Zygoptera), dragonflies (Odonata, Anisoptera), and stoneflies (Plecoptera). The pr...
Attitudes of Australian veterinarians about the cause and treatment of lower-respiratory-tract disease in racehorses. A questionnaire was administered to members of the Australian Equine Veterinary Association to investigate their attitudes and behaviours regarding the cause, diagnosis and treatment of lower-respiratory-tract disease in racehorses. The most-important perceived risk factors related to the level of exposure and resistance to infectious agents, whereas factors associated with racing and climatic factors were lower ranked. By far the most-commonly implicated primary cause of disease was respiratory viruses. However, specific diagnostic tests (such as viral serology or virus isolation) were rarely...
Treatment of supraspinous bursitis by use of debridement in standing horses: 10 cases (1968-1999). To evaluate efficacy of debridement for treatment of supraspinous bursitis in horses and to evaluate the outcome. Methods: Retrospective study. Methods: 10 horses with clinical signs of supraspinous bursitis. Methods: Medical records were reviewed for signalment, anamnesis, results of physical and radiographic examination, microbial culture results of supraspinous bursa tissue or exudate, Brucella abortus titers, type of antimicrobial and anti-inflammatory therapies, surgical technique, complications of the surgical procedure, and findings on histologic examination of excised nuchal ligament a...
In vitro detection of equine arteritis virus from seminal plasma for identification of carrier stallions. Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU...
Development of a differential multiplex PCR assay for equine herpesvirus 1 and 4 as a diagnostic tool. In this study, a multiplex polymerase chain reaction (PCR) procedure was developed for differentiation of strains and field isolates of equine herpesvirus type 1 (EHV-1) and type 4 (EHV-4). Specific oli-gonucleotide primers were combined to amplify the thymidine kinase (TK) gene region of EHV-1 and EHV-4, which would yield fragments of different lengths for each virus in the same amplification reaction. The specificity of the largest PCR amplicon for EHV-4 was confirmed by restriction digestion with HindIII. The multiplex PCR proved to be a fast and sensitive method for typing EHV-1 and EHV-4 ...
Equine viral arteritis. Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Equine viral arteritis. Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Equine viral arteritis. Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
