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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.
Development of a real-time RT-PCR assay for improved detection of Borna disease virus. Borna disease virus (BDV) is a non-segmented, negative-stranded RNA virus, which infects cells of the central nervous system (CNS) in many different species. BDV is the causative agent of the neurological disorders in horses and sheep termed classical Borna disease (BD), as well as staggering disease in cats. At present, the diagnosis staggering disease or feline BD is made by histopathology or immunohistochemistry of the CNS. In order to obtain a better clinical diagnostic tool, a duplex real-time RT-PCR assay (rRT-PCR) was developed. TaqMan probes and primers specific for the BDV P and BDV L...
[Equine herpesvirus 2: A study on the relation between viral excretion and respiratory disease in thoroughbred horses]. Equine herpesvirus 2 (EHV-2) was isolated from healthy animals; therefore, the association between EHV-2 infection and respiratory disease raises the question of the role of this agent in this pathology. To date, there are no reports that relate viral excretion to health, this study then analysed 153 nasal swabs from horses in different age groups (older and younger than 1 year old) and state of health (clinically healthy and with respiratory symptoms). Results showed that the percentage of horses with viral excretion was higher within the clinically healthy group, being significative (p < 0.0...
Risk factors for development of acute laminitis in horses during hospitalization: 73 cases (1997-2004). To identify risk factors for development of acute laminitis in horses during hospitalization for illness or injury. Methods: Retrospective case-control study. Methods: 73 horses that developed laminitis (case horses) and 146 horses that did not develop laminitis (control horses) during hospitalization. Methods: Case and control horses were matched in a 2:1 ratio by the date on which each horse was evaluated. Potential risk factors investigated included age, breed, and sex; highest and lowest values recorded during hospitalization for fibrinogen concentration, WBC count, PCV, and total solids c...
Investigations on outbreaks of African horse sickness in the surveillance zone in South Africa. Confirmed outbreaks of African horse sickness (AHS) occurred in the surveillance zone of the Western Cape in 1999 and 2004, both of which led to a two-year suspension on the export of horses. Light trap surveys in the outbreak areas showed that known vector competent Culicoides species, notably C. imicola, were abundant and present in numbers equal to those in the traditional AHS endemic areas. Isolations of AHS virus serotypes 1 and 7, equine encephalosis virus, and bluetongue virus from field-collected C. imicola in the surveillance zone demonstrated that this species was highly competent an...
Observed prevalence of tick-borne pathogens in domestic animals in Sicily, Italy during 2003-2005. The objective of this study was to characterize the observed prevalence of tick-borne pathogens (TBP) in domestic animals in Sicily, Italy during 2003-2005. Serological (competitive ELISA and indirect immunofluorescence antibody, n = 3299) and DNA tests (polymerase chain reaction and reverse line blot, n = 2565) were conducted on horse, donkey, cattle, sheep, goat, pig and dog samples. Pathogens analysed included Anaplasma, Ehrlichia, Rickettsia, Babesia and Theileria species, and Coxiella burnetii. The most prevalent TBP were Anaplasma and Babesia species. The results reported herein suggeste...
Burkholderia Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis. The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. Results: Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA)...
Genotypic characterization of VapA positive Rhodococcus equi in foals with pulmonary affection and their soil environment on a warmblood horse breeding farm in Germany. Pulsotypes of VapA positive Rhodococcus equi isolated from foals and soil on a farm in Germany were characterized on the basis of nasal and tracheal samples simultaneously collected in 2003 from 217 foals with sonographic evidence of pneumonia or pulmonary abscesses. Of the 217 double samples, R. equi was isolated in 118 (54%) of the tracheal samples and in 52 of the nasal swab samples (24%) (P<0.001). Furthermore, 37 and 55 isolates were also randomly selected from nasal swabs and the tracheal samples, respectively, and further processed to determine the presence of VapA by colony blot enz...
Outbreak of neurologic disease caused by equine herpesvirus-1 at a university equestrian center. Equine herpesvirus type 1 (EHV-1) infection causes neurologic disease in horses. However, risk factors for the disease and long-term prognosis are poorly characterized. Objective: There are identifiable risk factors for equine herpes-1 myeloencephalopathy. Methods: The entire population of 135 horses housed within the equestrian facility. Methods: A descriptive study investigated the clinical, serologic, virologic, and management aspects of an outbreak of EHV-1 myeloencephalopathy. Results: Out of 135 horses at the facility, 117 displayed signs of EHV-1 infection. Forty-six horses developed ne...
Characterization of multidrug resistant Salmonella recovered from diseased animals. Three hundred and eighty Salmonella isolates recovered from animal diagnostic samples obtained from four state veterinary diagnostic laboratories (AZ, NC, MO, and TN) between 2002 and 2003 were tested for antimicrobial susceptibilities and further characterized for bla(CMY) beta-lactamase genes, class 1 integrons and genetic relatedness using PFGE. Forty-seven serovars were identified, the most common being S. Typhimurium (26%), S. Heidelberg (9%), S, Dublin (8%), S. Newport (8%), S. Derby (7%), and S. Choleraesuis (7%). Three hundred and thirteen (82%) isolates were resistant to at least one ...
West Nile Virus in horses, sub-Saharan Africa. To evaluate the presence and extension of West Nile virus where French soldiers are stationed in Africa, specific antibody prevalence was determined by using ELISA and Western blot. Among 245 horses living in close proximity to the soldiers, seroprevalence was particularly high in Chad (97%) and Senegal (92%).
Avian titer development against West nile virus after extralabel use of an equine vaccine. West Nile virus affects many animals, but the highest prevalence of morbidity and mortality is observed in birds, horses, and humans. The purpose of this study was to determine a protocol in birds of prey and corvids, using a vaccine developed for horses. The birds were assigned to five groups. Groups 1-4 received 0.25 ml, 0.5 ml, 0.75 ml, and 1.0 ml, respectively, and group 5 served as a control group. The greatest percentage of seroconversion (58.3%) was observed in the vaccine group that received a dose of 1.0 ml administered thrice, 3 wk apart. This report demonstrates that a vaccine devel...
Development and characterization of an infectious cDNA clone of the virulent Bucyrus strain of Equine arteritis virus. Strains of Equine arteritis virus (EAV) differ in the severity of the disease that they induce in horses. Infectious cDNA clones are potentially useful for identification of genetic determinants of EAV virulence; to date, two clones have been derived from a cell culture-adapted variant of the original (Bucyrus) isolate of EAV, and it has previously been shown that recombinant virus derived from one of these (rEAV030) is attenuated in horses. A complete cDNA copy of the genome of the virulent Bucyrus strain of EAV has now been assembled into a plasmid vector. In contrast to rEAV030, recombinant...
Correlation between the induction of Th1 cytokines by an attenuated equine infectious anemia virus vaccine and protection against disease progression. The equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) has been used to protect against equine infectious anaemia (EIA) disease for several decades in China. The attenuated mechanism and immunological protective mechanisms remain to be elucidated. To identify responses that correlate with the protection against disease, we immunized horses with DLV, followed by challenge with an EIAV wild-type strain LN. All vaccinated horses were asymptomatic and had a low level of virus replication (<10 copies ml-1). The expression level of cytokines including gamma interferon...
Immune selection of equine infectious anemia virus env variants during the long-term inapparent stage of disease. The principal neutralizing domain (PND) of equine infectious anemia virus (EIAV) is located in the V3 region of SU. Genetic variation in the PND is considered to play an important role in immune escape and EIAV persistence; however, few studies have characterized genetic variation in SU during the inapparent stage of disease. To better understand the mechanisms of virus persistence, we undertook a longitudinal study of SU variation in a pony experimentally inoculated with the virulent EIAV(Wyo). Viral RNA isolated from the inoculum and from sequential sera samples was amplified by RT-PCR, clon...
Vaccine potential of novel surface exposed and secreted proteins of Streptococcus equi. Streptococcus equi, a clonal descendent of an ancestral S. zooepidemicus, causes equine strangles, a highly contagious purulent lymphadenitis of the head and neck. The aim of this study was to evaluate as vaccine components novel surface exposed or secreted S. equi proteins identified in an expression gene library with sera from resistant horses. Six proteins expressed by S. equi CF32 but not by S. zooepidemicus 631 were used to vaccinate one group of eight ponies. A second pony group was immunized with five adhesin and other proteins encoded by genes of Linkage Gr 1. All ponies made strong se...
A comparison of Freund’s Complete and Freund’s Modified Adjuvants used with a contraceptive vaccine in wild horses (Equus caballus). Fifteen captive wild mares (Equus caballus) were treated with porcine zona pellucida contraceptive vaccine and either Freund's Complete Adjuvant (n = 7) or Freund's Modified Adjuvant (n = 8). All mares received a booster inoculation of porcine zona pellucida plus Freund's Incomplete Adjuvant a month later. Anti-porcine zona pellucida antibodies were measured over 10 mo following the initial inoculation. There were no significant differences in antibody titers at any point during the 10 mo, and seven of the eight mares in the Freund's Modified Adjuvant group were above the 60% level at the end ...
First description of the horse stomach worm, Habronema muscae (Spirurida: Habronematidae) by scanning electron microscopy. Habronema muscae (Spirurida: Habronematidae) occurs in the stomach of equids, is transmitted by adult muscid dipterans and causes gastric habronemiasis. Scanning electron microscopy (SEM) was used to study the morphological aspects of adult worms of this nematode in detail. The worms possess two trilobed lateral lips. The buccal cavity was cylindrical, with thick walls and without teeth. Around the mouth, four submedian cephalic papillae and two amphids were seen. A pair of lateral cervical papillae was present. There was a single lateral ala and in the female the vulva was situated in the mid...
Disseminated cryptococcosis including osteomyelitis in a horse. A 4-year-old Arab mare was diagnosed with disseminated cryptococcosis, including osteomyelitis of the proximal phalanx of the left hind limb, osteomyelitis with associated soft tissue granuloma of a rib and disseminated, large cryptococcal nodules in the lungs. The lesion in the dorsoproximal aspect of the proximal phalanx had a large area of cortical lysis with spiculated periosteal new bone and extensive soft tissue swelling. The affected rib had a pathological fracture. Cryptococcal osteomyelitis has not been previously reported in horses but should be considered as a differential diagnosis...
Detection of viruses in nasal swab samples from horses with acute, febrile, respiratory disease using virus isolation, polymerase chain reaction and serology. To examine the association of viruses with acute febrile respiratory disease in horses. Design Nasal swab and serum samples were collected from 20 horses with acute febrile upper respiratory disease that was clinically assessed to have a viral origin. Methods: Each of the samples was inoculated onto equine fetal kidney, RK13 and Vero cell cultures, and viral nucleic acid was extracted for polymerase chain reaction (PCR) or reverse transcription PCR. PCR primers were designed to amplify nucleic acid from viruses known to cause or be associated with acute febrile respiratory disease in horses in...
Evidence of the partial effects of inactivated Japanese encephalitis vaccination: analysis of previous outbreaks in Japan from 1953 to 1960. To evaluate the partial effects of vaccination against equine Japanese encephalitis (JE) and characterize other prognostic factors based on previous outbreak records in Japan from 1953 to 1960. Methods: Individual case records, which included demographic information, vaccination history, and clinical information (dates of onset, recovery and death, and symptoms), were investigated. The relations between two outcomes, JE death and symptomatic period, and other variables were examined. Results: Of a total reported 803 cases during the observation period, 453 (56.5%) were diagnosed with either se...
Genetic typing of equine arteritis virus isolates from Argentina. We report the nucleotide sequence and genetic diversity of four Equine Arteritis Virus (EAV) ORF 5 and 6 from Argentina isolates, obtained from asymptomatic virus-shedding stallions. Nucleic acid recovered from the isolates were amplified by RT-PCR and sequenced. Nucleotide and deduced amino acid sequences from the Argentine isolates were compared with 17 sequences available from the GenBank. Phylogenetic analysis revealed that the Argentine isolates grouped together in a definite cluster near European strains. Despite the greater genetic variability among ORF 5 from different isolates and str...
Multiplex real-time PCR for the detection and differentiation of equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4). A multiplex real-time PCR was designed to detect and differentiate equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4). The PCR targets the glycoprotein B gene of EHV-1 and EHV-4. Primers and probes were specific to each equine herpesvirus type and can be used in monoplex or multiplex PCRs, allowing the differentiation of these two closely related members of the Alphaherpesvirinae. The two probes were minor-groove binding probes (MGB) labelled with 6-carboxy-fluorescein (FAM) and VIC for detection of EHV-1 and EHV-4, respectively. Ten EHV-1 isolates, six EHV-1 positive clinical samples...
A novel Salmonella genomic island 1 and rare integron types in Salmonella Typhimurium isolates from horses in The Netherlands. To investigate the genotypic resistance of integron-carrying Salmonella Typhimurium isolates from horses and their genetic relationship. Methods: Sixty-one Salmonella isolates were screened for the presence of class 1 integrons by PCR. The gene cassettes of integron-positive isolates were detected by PCR, restriction fragment length polymorphism typing, and sequencing. The potential for the transfer of resistance determinants was investigated by conjugation experiments. The presence of Salmonella genomic island 1 (SGI1) or its variants was studied by PCR and nucleotide sequencing. PFGE was use...
Cerebellar abscess due to Rhodococcus equi in an immunocompetent patient: case report and literature review. Rhodococcus equi (R. equi) is a facultative, intracellular, nonmotile, non-spore-forming, gram-positive coccobacillus, primarily causes zoonotic infections that affect grazing animals, mainly horses and foals and is a rare opportunistic pathogen found in severely compromised patients, and most commonly in recent years, in human immunodeficiency virus (HIV)-infected persons. Early cases, most in patients receiving immunosuppressant therapy, were more likely to be successfully treated with antimicrobial agents than cases in AIDS patients, it is emerging as an important pathogen in patients with ...
Incidence and effects of West Nile virus infection in vaccinated and unvaccinated horses in California. A prospective cohort study was used to estimate the incidence of West Nile virus (WNV) infection in a group of unvaccinated horses (n = 37) in California and compare the effects of natural WNV infection in these unvaccinated horses to a group of co-mingled vaccinated horses (n = 155). Horses initially were vaccinated with either inactivated whole virus (n = 87) or canarypox recombinant (n = 68) WNV vaccines during 2003 or 2004, prior to emergence of WNV in the region. Unvaccinated horses were serologically tested for antibodies to WNV by microsphere immunoassay incorporating recombinant WNV E ...
Helicobacter equorum sp. nov., a urease-negative Helicobacter species isolated from horse faeces. Gram-negative, curved, motile bacteria (strains EqF1T and EqF2) were isolated from faecal samples from two clinically healthy horses. Both strains possessed a single, monopolar, sheathed flagellum and were urease-negative. The novel strains grew at 37 degrees C under microaerobic conditions and were positive for oxidase, catalase and alkaline phosphatase activities. The isolates reduced nitrate to nitrite, but gamma-glutamyl transpeptidase activity was not detected. The novel isolates did not grow at 42 degrees C or on media containing 1 % glycine. They were resistant to cephalotin and nalidix...
Capsid protein of eastern equine encephalitis virus inhibits host cell gene expression. Eastern equine encephalitis virus (EEEV) causes sporadic but often severe cases of human and equine neurological disease in North America. To determine how EEEV may evade innate immune responses, we screened individual EEEV proteins for the ability to rescue the growth of a Newcastle disease virus expressing green fluorescent protein (NDV-GFP) from the antiviral effects of interferon (IFN). Only expression of the EEEV capsid facilitated NDV-GFP replication. Inhibition of the antiviral effects of IFN by the capsid appears to occur through a general inhibition of cellular gene expression. For ex...
