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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.
Equine infectious anemia. The ability of EIAV to persistently infect horses in the face of a profound immune response by the host makes it a potentially devastating disease for the horse population of the United States. Its ability to evade host immune defenses by lying dormant in apparently healthy animals and by rapidly changing its antigenic determinants is proving to be a major obstacle to vaccine development. Because most infected horses appear clinically normal and a large proportion of horses in this country remain untested, the virus is not likely to be eradicated in the near future. Yet, for the same reason, b...
Clostridia-associated enterocolitis in adult horses and foals. A review of the literature describing clostridia-associated enterocolitis is presented. The bacteria, their toxins, and possible factors that interact to contribute to the pathogenesis of enterocolitis are described. Clinical signs associated with clostridia-associated enterocolitis, methods of diagnosis, treatments, and preventive strategies are discussed.
Application of epidemiologic principles and methods to investigating and controlling equine infectious diseases. Epidemiology is a tool much like any other diagnostic tool that the practitioner uses as an aid in the complete physical examination of the group of animals. It can be used to generate a specific differential diagnosis list. Epidemiology is especially useful to design a disease control and prevention program by helping to elucidate the key determinants of disease occurrence.
[Pilot study of the occurrence of Prototheca in fecal samples of horses]. Fecal samples of 146 horses were culturally investigated for occurrence of Prototheca spp. using a selective medium, developed by PORE (1973). Prototheca zopfii could be isolated in monoculture from 9 fecal samples (6.2%). The results of this pilot study show that horses too can harbour and shed Prototheca spp. in variable frequency.
Equine ehrlichiosis. Equine ehrlichiosis is a seasonal disease of horses first reported in 1969. Clinical signs in horses include high fever, depression, partial hypophagia, anorexia, limb edema, petechiation, icterus, ataxia, and reluctance to move. Hematologic changes include leukopenia, thrombocytopenia, icterus, anemia, and inclusion bodies, principally in neutrophils and occasionally in eosinophils. Diagnosis is made by clinical signs and observing characteristic morulae in a blood smear with standard Wright's stain. Mortality is low unless secondary infection develops or injury occurs as a result of incoordi...
Equine rabies. With the continued increase in the number of wildlife rabies cases reported across the United States and Canada, this disease will remain a threat to the horse as the potential for exposure to infected wildlife and other domestic animals is likely to also increase. Because there are no rapid, definitive antemortem diagnostic tests, the tentative diagnosis is based upon the variable and sometimes nonspecific clinical signs. Although the CSF analysis may be helpful in some cases, it may not be abnormal. Nor is collection of the specimen always practical in the field situation. The FAT on neural ...
Rhodococcus equi-associated osteomyelitis in foals. Two cases of Rhodococcus equi infection in foals are described, in which osteomyelitis was a feature. Because rhodococcal infection is usually low grade and chronic, and because the signs of early metaphysitis can be subtle, any articular or periarticular swelling in a foal from a farm with a history of rhodococcosis should be strongly suspected to be associated with R equi until proven otherwise.
[Equine leukosis with progressive lameness–a case study]. A case of generalized equine leucosis is presented. The most important clinical signs were cachexia, loss of condition, fever, tachycardia, subcutaneous tumors and severe lameness accompanied by edema of the right thoracic limb. Hematology showed anemia and neutrophilia; clinical biochemistry indicated hypalbuminemia, hyperphosphatemia and hyperfibrinogenemia. Necropsy revealed multiple tumors throughout the body which mainly originated from lymph nodes. Histopathologically the tumors consisted of two cell-types: a. uniform lymphocytoid cells with a highly infiltrative growth pattern; b. heter...
Equine influenza. Influenza continues to be one of the most important diseases of horses despite the availability and widespread use of equine influenza vaccines for almost 30 years. In recent years, infection with the influenza A/equine/2 subtype has become endemic in the equine populations of North America, Europe, and Scandinavia. Continued antigenic drift of field virus has compromised the efficacy of vaccines, most of which contain antigens prepared from influenza viruses isolated more than 10 years ago. This article reviews the history, virology, epidemiology, pathogenesis, immunology, clinical presentati...
Rotaviral diarrhea. Rotavirus poses a challenge each foaling season to farm managers and veterinarians in intensive horse breeding areas throughout the world. By understanding the epidemiology of the disease as well as characteristics of the virus, veterinarians can make sound recommendations on prevention and control of outbreaks. Even when effective prophylactic products are developed, farm management practices, including quarantine, disinfection, and hygiene, will always need to be in force to prevent any contagious disease outbreak.
[Reproduction data in breeding mares, diseases and losses among suckling foals and preventive husbandry in German stud farms]. By means of a survey, the reproductive rate of mares and the foal losses in ten Thoroughbred, Saddlebred and Pony studs in Germany, mainly from North-Rhine-Westfalia, were collected and evaluated. Data for the survey were recorded for 1985-1990. The study also examined the hygienic management in the surveyed studs, and the morbidity rate of suckling foals was obtained for 1990. In addition to the survey questionnaire each stud was visited once. Two studs of each horse group were visited several times every week from March to August in order to evaluate as exactly as possible the husbandry and ...
Characterization of virulence variants of African horsesickness virus. There are three clinicopathologic syndromes associated with African horsesickness (AHS) virus infection in horses. These different forms of AHS (pulmonary, cardiac, and fever forms) vary in the organs affected, the severity of lesions, time of onset of clinical signs and mortality rates. We have studied the effects of infection with three cell culture passaged variants of AHS virus in naive North American horses. One of these viruses, AHS/4SP, consistently caused the pulmonary form of AHS with rapid onset of severe pulmonary edema and 100% mortality. A second variant, AHS/9PI, resulted in sign...
Evaluation of agar gel immunodiffusion and indirect fluorescent antibody assays as supplemental tests for dourine in equids. The agar gel immunodiffusion (AGID) and indirect fluorescent antibody (IFA) assays were evaluated as supplemental tests to the complement-fixation (CF) test, the official US importation certification test for dourine in equids. The American stabilate (n = 10 animals) or the Canadian stabilate (n = 6 animals) of Trypanosoma equiperdum cultured in rat blood was administered by catheterization and infusion in the urogenital tract of 16 equids. To assess parasitemia and serologic responses by use of the CF, AGID, and IFA tests, a total of 787 serum and blood samples were obtained from equids befor...
Salmonellosis. Salmonellosis is the most common infectious cause of diarrhea or colitis in horses. It can be associated with high fatality rates in patients with compromised host defenses. The increasing incidence of infection and antimicrobial resistance present a challenge for the practicing veterinarians. The epidemiology and pathogenesis of salmonellosis are reviewed. Diagnosis, treatment, and control of disease are discussed.
Hematuria and leptospiruria in a foal. A Thoroughbred foal that was born after 305 days of gestation was referred 6 hours after birth. On initial examination, the foal was alert, but weak and unable to stand. Heart rate was 150 beats/min, respiratory rate was 48 breaths/min, and rectal temperature was 33 C. Leukocytosis was detected (26,000 WBC/microliters). Dysuria and passage of red urine was observed approximately 30 hours after admission. Urine collected by free catch had a 3+ reaction for blood on dipstick analysis. Examination of Warthin Starry-stained sections of allantochorion revealed organisms morphologically characterist...
Correction of patellar luxation by recession sulcoplasty in three foals. Lateral luxation of the patella in four femoropatellar joints of three foals was repaired by recession sulcoplasty and medial imbrication of the joint. One foal was euthanatized because of septic arthritis caused by incisional dehiscence, and the other two foals were normal 2 years after surgery. Recession sulcoplasty combined with medial imbrication of the joint capsule resulted in a functional femoropatellar joint and should be considered in foals affected with lateral patellar luxation.
Coccidioides immitis mastitis in a mare. No abstract available
Characterization of the myristylated polypeptide encoded by the UL1 gene that is conserved in the genome of defective interfering particles of equine herpesvirus 1. Equine herpesvirus 1 (EHV-1, Kentucky A strain) preparations enriched for defective interfering particles (DIPs) can readily establish persistent infection. The UL1 gene, which is conserved in the genome of DIPs that mediate persistent infection, maps between nucleotides 1418 and 2192 (258 amino acids) from the L (long) terminus. UL1 has no homology with any known gene encoded by herpes simplex virus type 1 but has limited homology to open reading frame 2 of varicella-zoster virus and the "circ" gene of bovine herpesvirus type 1. Previous work showed that the EHV-1 UL1 gene belongs to the earl...
Generation and partial characterization of an eosinophil chemotactic cytokine produced by sensitized equine mononuclear cells stimulated with Strongylus vulgaris antigen. Supernatants generated by stimulation of peripheral blood mononuclear cells (PBMC) from Strongylus vulgaris sensitized or immunized ponies were assayed in vitro for eosinophil chemotactic activity (ECA) using the filter system in blind well chambers. The supernatants from these cultures were chemotactic for eosinophils, but not for neutrophils. Supernates from cultures of unsensitized PBMC stimulated with S. vulgaris antigen were not chemotactic for eosinophils. ECA was first detected in culture supernatants after 1.5 h of incubation and was dependent on both antigen and PBMC concentrations, b...
Histoplasmosis in horses. Histoplasmosis was diagnosed in nine horses during 1986-1990. The infection with Histoplasma capsulatum caused granulomatous placentitis and abortion in one mare in the 7th month of gestation and three mares in the 10th month. Four newborn foals died from severe granulomatous pneumonia within a few days of birth; and a weanling thoroughbred developed granulomatous pneumonia and lymphadenitis at 5 months of age.
Comparison of five tests for the serologic diagnosis of myiasis by Gasterophilus spp. larvae (Diptera: Gasterophilidae) in horses and donkeys: a preliminary study. Sera from 41 horses and 159 donkeys, from twelve States of México, were tested to ascertain anti-Gasterophilus circulating antibodies by double immunodiffusion (DD), counterimmunoelectrophoresis (CIE), indirect haemagglutination (IH), thin layer immunoassay (TIA) and diffusion-in-gel ELISA (DIG-ELISA) methods using crude somatic antigen from third instar larvae of G. intestinalis (DeGeer). At necropsy, 33/41 horses and 24/159 donkeys were found to be parasitized by G. intestinalis and/or G. nasalis (L.). Gasterophilus intestinalis was the species most commonly found in the equines. Analysis o...
Streptococci and Pasteurella spp. associated with disease of the equine lower respiratory tract. The likelihood of finding evidence of inflammation in 551 tracheal washes collected endoscopically from 278 Thoroughbred racehorses increased with the number of bacterial colony forming units (cfu) per ml of wash (P < 0.001). The aerobic bacteria Streptococcus zooepidemicus, Pasteurella/Actinobacillus-like species and Streptococcus pneumoniae were significantly associated with lower airway inflammation whereas coagulase-negative Staphylococcus spp., alpha-haemolytic Streptococcus spp., Acinetobacter spp., Bacillus spp., Escherichia coli, Pseudomonas aeruginosa, non-haemolytic Streptococcus spp...
Development of neutralizing antibody in horses infected with Ehrlichia risticii. The role of the humoral immune response in ehrlichial infection is unknown. Development of neutralizing antibodies during a course of Ehrlichia risticii infection in a pony was examined in vitro by determining the inhibition of E. risticii infection of P388D1 cells in the presence of the sera. The pony experimentally infected with E. risticii developed significant neutralizing activity in the sera by 15 days postinfection when parasitemia started to decline. Neutralizing activity continued to rise after recovery from the disease up to 34 days postinfection at which time the experiment was term...
Neutrophil chemotaxis in the horse is not mediated by a complex of equine neutrophil elastase and equine alpha-1-proteinase inhibitor. Studies have demonstrated that as a result of proteolytic inactivation or complex formation (with neutrophil elastase), human alpha-1-proteinase inhibitor (API) becomes a potent chemoattractant for human neutrophils. The present study aimed to investigate the in vitro chemotactic response of equine neutrophils to an equivalent complex of equine API and neutrophil elastase. No evidence of neutrophil migration was observed towards purified complex derived from equine neutrophil elastase and the Spi 1 isoform of equine API, or to crude mixtures of porcine pancreatic elastase and unseparated equin...
Development of a competitive enzyme-linked immunosorbent assay for detection of bovine, ovine, porcine, and equine antibodies to vesicular stomatitis virus. Two competitive (C) enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of antibodies to vesicular stomatitis virus (VSV) in animal sera. The assays are based upon the availability of polyclonal antibodies (PAbs) from mouse ascitic fluids prepared against the New Jersey (NJ) and the Indiana (IN) VSV serotypes. The assays were performed by the immobilization of VSV-NJ and VSV-IN antigens on a solid phase (microtiter plate). Appropriately diluted test serum mixed with an equal volume of serotype-specific PAb was allowed to incubate in the presence of the relevant VSV ant...
In-vitro susceptibility to antimicrobial drugs of bacterial isolates from horses in The Netherlands. Minimum inhibitory concentrations (MICs) of 30 antimicrobial agents (including the hitherto unreported antimicrobial agents doxycycline, minocycline, vanomycin, 3 quinolones and 3 combinations of antimicrobial agents) for isolates of Salmonella spp. (20), Escherichia coli (17), Klebsiella spp. (8), Proteus spp. (7), Pseudomonas aeruginosa (7), Actinobacillus equuli (5), Rhodococcus equi (4), Streptococcus zooepidemicus (23), Streptococcus equisimilis (6), Streptococcus equi (4), coagulase-positive Staphylococcus spp. (20) and Taylorella equigenitalis (19) were determined using the agar dilutio...
Relationship between onset of puberty and establishment of persistent infection with equine arteritis virus in the experimentally infected colt. The relationship between stage of reproductive tract maturity and susceptibility to the experimental establishment of persistent infection with equine arteritis virus (EAV) was investigated in 21 prepubertal and 15 peripubertal colts. Five of six prepubertal colts inoculated intranasally remained infected in the reproductive tract from post-challenge day 28 to 93 and two of six from post-challenge day 120 to 180. No virus was detected in five of these animals killed on post-challenge day 210. Each of two peripubertal colts remained infected in the reproductive tract at post-challenge day 60 an...
Evaluation of intradermal mould antigen testing in the diagnosis of equine chronic obstructive pulmonary disease. Intradermal end-point titres for commercial aqueous extracts of Micropolyspora faeni, Thermoactinomyces vulgaris and Aspergillus fumigatus were determined in control and chronic obstructive pulmonary disease (COPD) affected horses. The intradermal end-point titres of control and COPD-affected horses were not significantly different and values for individual horses for M. faeni, A. fumigatus and T. vulgaris were not correlated with the pulmonary dysfunction or with the bronchoalveolar lavage fluid neutrophilia which had been induced by previous inhalation challenges with these antigens and by '...
