Topic:Pneumonia
Pneumonia in horses is a respiratory condition characterized by inflammation of the lungs, often caused by bacterial, viral, or fungal infections. It can affect horses of all ages, though young and immunocompromised animals are more susceptible. Clinical signs of pneumonia in horses may include coughing, nasal discharge, fever, and labored breathing. Diagnosis typically involves a combination of clinical examination, imaging techniques such as radiography or ultrasonography, and laboratory tests including blood work and microbial cultures. Treatment strategies vary depending on the underlying cause and may involve antimicrobial therapy, supportive care, and environmental management. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathophysiology, diagnosis, and treatment of pneumonia in equine populations.
Clinical evaluation of the serodiagnostic value of enzyme-linked immunosorbent assay for Rhodococcus equi infection in foals. An enzyme-linked immunosorbent assay (ELISA) for detection of serum IgG antibodies against Tween 20-extracted antigen of strain ATCC 6939 was applied in Hidaka, Japan to a total of 752 sick foals showing a variety of signs of infectious disease. An optical density (OD) value of more than 0.3 was tentatively fixed to be positive on the basis of readings made of healthy horse sera in previous studies. During a 2 year study, 138 of the 752 sick foals showed an OD value of 0.3 or higher and were designated as 'suspected of R. equi infection'. Age distribution during the initial medical examination...
Pathogenesis and virulence of Rhodococcus equi. Inhalation of the soil-borne organism, Rhodococcus equi, can lead to a chronic and severe pyogranulomatous pneumonia in young horses and immunocompromised people. In addition, ulcerative colitis is a common sequela to infection in foals, and dissemination from the lung to other body sites is not uncommon in either the horse or man. Although the facultative intracellular bacterium is susceptible to neutrophil-mediated killing, it is able to resist innate macrophage defenses and establish residence within the intracellular environment of that phagocyte. Definitive virulence factors of R. equi ha...
Immunity to Rhodococcus equi. Rhodococcal pneumonia is an important, life threatening disease of foals and immunosuppressed humans. Increased knowledge of the mechanisms of protective immunity are required in order to develop an effective immunoprophylaxis strategy for horses and immunotherapeutic regiments for people. Both humoral and cellular components of the immune system may be involved in immune clearance of R. equi. The susceptibility of foals less than 4-6 months of age is postulated to reflect waning maternal antibody, and passive transfer of hyperimmune plasma can provide protection on endemic farms. However, eff...
Comparison of tracheal aspiration with other tests for diagnosis of Rhodococcus equi pneumonia in foals. The diagnostic value of tracheal aspiration was evaluated through comparison with other diagnostic methods using an experimental model of Rhodococcus equi (R. equi) pneumonia in foals. Pneumonia was induced by spraying of the virulent R. equi strain ATCC 33701 into the trachea of foals. All foals developed fever from 11 to 16 days after bacterial inoculation. One foal was euthanized on day 26 due to its poor prognosis, and other foals euthanized on day 43. During the experiment, some tests for diagnosis of Rhodococcus equi pneumonia such as tracheal aspiration, radiography, serodiagnosis and f...
Pathogenicity and virulence of Rhodococcus equi in foals following intratracheal challenge. Twelve foals, between 27 and 83 days old, were infected with 2 strains of Rhodococcus equi by intratracheal administration. Ten of the 12 foals were inoculated with 10(4)-10(10) colony forming units (cfu) of ATCC 33701 strain. The other 2 foals were inoculated with 10(9) cfu of a plasmid-cured derivative of the ATCC 33701 strain (ATCC 33701P-). All of the 10 foals challenged with the ATCC 33701 strain showed clinical signs of pulmonary disease within 5-13 days, such as gross lesions associated with acute bronchopneumonia and microscopic lesions associated with granulomatous pneumonia. The two ...
Antigenic analysis of Rhodococcus equi preparations using different horse sera. An R. equi vaccine, prepared under conditions which induce the expression of many antigens, and which has given encouraging results in field trials, was analyzed by SDS-PAGE and immunoblots and compared with other R. equi preparations: a preparation made in with the same technique from a nonvirulent isolate (virulence associated protein negative, VapA-negative); a whole cell preparation of a VapA-positive R. equi, prepared as a standard bacterin; and a semipurified VapA preparation (APTX). The antigens in these preparations were analyzed using hyperimmune sera (from adult horses vaccinated wit...
Immunoprophylaxis of Rhodococcus equi pneumonia in foals. An immunoprophylaxis program for R. equi infection of foals has been established on a number of thoroughbred breeding farms in Argentina over the past 4 years. Nearly 800 mares annually were immunized subcutaneously during the last 2 months of pregnancy with 2-3 doses of a vaccine containing soluble antigens of R. equi, including the virulence associated protein (VapA) and 'equi factors' exoenzymes. The mortality from R. equi pneumonia in the foals from vaccinated dams dropped from an average of 3% in the 5 years before the vaccination program was initiated to an average of 1.2% in the 4 years...
Prevention of Rhodococcus equi pneumonia of foals using two different inactivated vaccines. Two different, inactivated, aluminium salt adsorbed vaccines, one containing a R. equi strain (serotype 1, 10(9) CFU/ml and equine herpesvirus 2 (EHV-2) (1.5 x 10(7) PFU/ml) and another containing R. equi only were used on three studfarms to determine whether the disease can be prevented by vaccination of both pregnant mares and their foals. Pregnant mares received two 3 ml doses of vaccine intramuscularly 6 and 2 weeks before parturition and their foals were vaccinated on two or three occasions at 3, 5 or 7 weeks of age. The efficacy of the vaccines was evaluated on the basis of the clinical ...
Acute hemorrhagic pulmonary infarction and necrotizing pneumonia in horses: 21 cases (1967-1993). To characterize history, clinical signs, and pathologic findings in horses with histologically confirmed acute hemorrhagic pulmonary infarction and necrotizing pneumonia. Methods: Retrospective study. Methods: 21 horses. Results: 19 of the 21 horses were Thoroughbred racehorses in training. Eighteen horses had had strenuous exercise immediately prior to onset of illness. Fifteen horses had a serosanguineous nasal discharge during hospitalization. Seventeen horses had radiographic evidence of pulmonary consolidation and pleural effusion. Nine of 14 horses had ultrasonographic evidence of large ...
Acquired B lymphocyte deficiency and chronic enterocolitis in a 3-year-old quarter horse. This case report describes a 3-year-old American Quarter Horse with acquired immunodeficiency. Clinical signs included chronic diarrhea due to Salmonella typhimurium and bacterial pneumonia. Characterization of the immunodeficiency involved in vivo phytohemagglutinin (PHA) intradermal testing, in vitro lymphocyte proliferation in response to concanavalin A, immunofluorescence flow cytometry data on blood lymphocytes, serum protein electrophoresis and immunoglobulin (Ig) quantification. A diagnosis of B lymphocyte deficiency with resulting deficiencies in serum IgG, IgA and IgM and a concurrent...
Prevalence of the virulence-associated gene of Rhodococcus equi in isolates from infected foals. The prevalence of the plasmid-encoded virulence-associated gene (vapA) of Rhodococcus equi, as determined by PCR, was found to be 98% in isolates from 154 foals with pneumonia, confirming the strong association of vapA with virulence. The vapA genes from 60 representative isolates were compared by digestion with the restriction endonuclease HinfI, and no evidence of sequence variation was detected.
Use of Rhodococcus equi virulence-associated protein for immunization of foals against R equi pneumonia. To evaluate use of the virulence-associated protein of Rhodococcus equi in immunizing foals against R equi pneumonia. Methods: Eight (experimental group) and 6 (controls) mares with their foals. Methods: Virulence-associated protein extracted from R equi was used to prepare an acetone-precipitated. Triton X-extracted (APTX) antigen. After determination of the efficacy of passive immunization, in untreated foals or in foals given plasma from a horse vaccinated with APTX antigen or from a nonvaccinated horse, a field trial was done to evaluate the efficacy of vaccination of 8 mares, twice with A...
Antibiotic prophylaxis of lower respiratory tract contamination in horses confined with head elevation for 24 or 48 hours. To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Methods: Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocy...
Chronic bronchopulmonary aspergillosis in a horse with Cushing’s syndrome. An atypical case of chronic equine bronchopulmonary aspergillosis with an unusual hyphal morphology was diagnosed in a horse with Cushing's syndrome. Because of the hyphal localization in chronic ectatic bronchi and bronchioles, and juxtabronchiolar processes, the observed type of aspergillosis is similar to 'saprophytic bronchopulmonary aspergillosis' or 'semi-invasive pulmonary aspergillosis' in humans. The aetiological diagnosis of aspergillosis was accomplished by the application of a panel of monospecific polyclonal and monoclonal antibodies in immunohistochemical techniques.
Identification of Rhodococcus equi using the polymerase chain reaction. Two regions in the gene coding for 16S rRNA in Rhodococcus equi were selected as species-specific primer sequences for the polymerase chain reaction (PCR). PCR using these primers was tested against 10 strains of R. equi (including the type strain) and gave positive results for all but was negative for all other tested species of Rhodococcus; representatives of the most closely related genera and a number of other bacterial species. This method could therefore be used to identify this species which can infect the lungs or other organs of horses, pigs, humans and other animals.
Equine cryptococcal endometritis and placentitis with neonatal cryptococcal pneumonia. No abstract available
Laryngospasm, dysphagia, and emaciation associated with hyperkalemic periodic paralysis in a horse. An 18-month-old Quarter Horse gelding was examined because of weight loss and dysphagia of 1 month's duration. Clinical signs included lethargy, dehydration, ptyalism, and probable aspiration pneumonia. Severe dyspnea and cyanosis were evident after mild exercise. Endoscopy revealed laryngospasm and pharyngospasm. Because clinical signs and endoscopic findings were suggestive of hyperkalemic periodic paralysis (HPP), acetazolamide treatment was instituted. Marked improvement was observed within 48 hours. The horse was determined to be homozygous for HPP. It is likely that this horse's dysphagi...
Serologic responses to Rhodococcus equi in individuals with and without human immunodeficiency virus infection. Thirty healthy blood donors, 15 workers from horse-breeding farms, 69 human immunodeficiency virus (HIV)-negative persons at risk for HIV infection, 125 HIV-infected subjects without Rhodococcus equi infection, and nine HIV-infected patients with Rhodococcus equi pneumonia were evaluated in order to detect serum antibodies to Rhodococcus equi precipitate-soluble antigen by an enzyme immunoassay (EIA). Whereas EIA values for healthy donors, horse farm workers, individuals at risk for HIV infection, and HIV-positive subjects without Rhodococcus equi infection were comparable, HIV-infected patien...
Equine herpesvirus type 2 (EHV-2) as a predisposing factor for Rhodococcus equi pneumonia in foals: prevention of the bifactorial disease with EHV-2 immunostimulating complexes. Equine herpesvirus type 2 (EHV-2), a member of the Gammaherpesvirinae subfamily, was studied in a two-phase respiratory disease complex of young foals as a predisposing factor for the secondary bacterial invasion of lungs with Rhodococcus equi (R. equi). Foals were immunized against EHV-2 on a farm where R. equi pneumonia regularly occurred during the last years. The immunizations were performed by using a subunit vaccine which selectively presents envelope glycoproteins of EHV-2 in a multimeric form of immunostimulating complexes (iscoms). The etiological role of EHV-2 was estimated by observ...
Rattlesnake venom poisoning in horses: 32 cases (1973-1993). To determine the clinical manifestations, morbidity, mortality, and treatment methods for rattlesnake venom poisoning in horses. Methods: Retrospective analysis of medical records. Methods: 27 horses with acute venom poisoning attributable to prairie rattlesnakes, and 5 with chronic problems subsequent to a rattlesnake bite. Results: Most horses were bitten on or near the muzzle while on pasture, resulting in head swelling, dyspnea, and epistaxis. Additional manifestations of acute poisoning included fever, tachycardia, tachypnea, cardiac arrhythmia, hemolytic anemia, thrombocytopenia, hemorrh...
Immunohistochemical detection of virulence-associated antigens of Rhodococcus equi in pulmonary lesions of foals. Rhodococcus equi was isolated from the lungs of six foals with bronchopneumonia. All isolates expressed 15-17-kd antigens by immunoblot analysis and contained a virulence-associated plasmid of 85 or 90 kb. Immunohistochemically, R. equi from all pulmonary lesions showed the expression of 15-17-kd antigens mainly in the phagocytic cells. The specific monoclonal antibody to 15-17-kd antigens of R. equi (MAb 10G5) may be an aid in the diagnosis of R. equi-induced pneumonia.
Prognosis for return to racing after recovery from infectious pleuropneumonia in thoroughbred racehorses: 70 cases (1984-1989). To determine the percentage of Thoroughbred racehorses that would be capable of racing performance after recovery from infectious pleuropneumonia. Methods: Retrospective case series. Methods: 70 Thoroughbred horses that had recovered from pleuropneumonia. Only horses 5 years old known to be in race training at the time of illness were included in the study. Results: Forty-three of the 70 (61%) horses raced after recovery, and 24 of the 43 (56%) won at least 1 race. Horses that required placement of an indwelling thoracic drain apparently did not have a worse prognosis than did horses that did...
Equine neonatal septicaemia: 24 cases. Equine neonatal septicaemia was confirmed in 24 foals hospitalised at the Rural Veterinary Centre between 1989 and 1992 with suspected septicaemia. Septicaemia was confirmed by culture of bacteria from blood of live foals and tissues obtained at necropsy of foals that died or were euthanased. Pathogenic bacteria isolated were predominantly Enterobacteriaceae (including Escherichia coli and Salmonella serovars) and Actinobacillus equuli. Clinical manifestations of septicaemia included signs of depression, dehydration, abnormalities in body temperature and manifestations of localised infection i...
Bacterial pneumonia associated with corticosteroid therapy in three horses. Three horses developed severe pulmonary infections while being treated with systemic corticosteroids for other diseases. Two of them had an immune-mediated skin disease, compatible with a diagnosis of pemphigus foliaceus, and one had severe chronic obstructive pulmonary disease. Case 1 developed diffuse pneumonia from which Streptococcus zooepidemicus and Bacteroides melaninogenicus were isolated, and it responded to antibiotic therapy. Case 2 developed septicaemia, pulmonary thrombosis and pneumonia associated with Escherichia coli, and died during a peracute illness with signs of disseminate...
Attempts to find phenotypic markers of the virulence plasmid of Rhodococcus equi. Four isolates of Rhodococcus equi, from pneumonic foals, and containing the 85 kb virulence plasmid, a porcine isolate containing an 80 kb plasmid, and their plasmid cured derivatives, were examined for 239 phenotypic properties in an attempt to find characters other than the virulence-associated protein (VapA) which might be encoded by the virulence plasmid in organisms grown at 37 degrees C. Tests chosen included those which have previously given variable results for R. equi isolates, since such variability might be attributed to plasmid curing, and characteristics which have been described ...
Subcutaneous emphysema in a neonatal foal. A 16-hour-old foal was examined because of subcutaneous emphysema, which began developing 3 hours after a routine delivery. Physical examination did not reveal soft-tissue or musculoskeletal trauma, and there were no skin injuries to explain the subcutaneous accumulation of air. Results of CBC and serum biochemical analysis were within reference limits, and findings on endoscopy of the pharyngeal area, trachea, and esophagus were within normal limits other than observation of dorsal pharyngeal compression. A pulmonary bulla, pneumomediastinum, and pneumothorax were detected on thoracic radiogr...