Evaluation of 5 serologic assays to detect Rhodococcus equi pneumonia in foals.
Abstract: To determine the sensitivity and specificity of 5 serologic assays used to diagnose Rhodococcus equi pneumonia in foals and to determine whether any of the assays could be used to identify affected foals prior to the onset of clinical signs or to differentiate between affected and unaffected foals when clinical signs first become apparent. Methods: Nested case-control study. Methods: 26 foals. Methods: Serum samples were obtained from all foals at 2, 4, and 6 or 7 weeks of age. Additional samples were obtained from affected foals at the time of diagnosis of R equi pneumonia and from age-matched unaffected foals. Samples were tested with 3 ELISA, an agar gel immunodiffusion assay, and a synergistic hemolysis inhibition assay. Results: Sensitivity and specificity data indicated that none of the assays could be used to reliably differentiate affected from unaffected foals at any testing period. Proportions of foals that had an increase in test values between paired samples collected at 4 and 6 or 7 weeks of age were not significantly different between affected and unaffected foals. For all assays, result values increased significantly over time; however, the rate of increase was not significantly different between affected and unaffected foals. Conclusions: Results suggest that serologic assays, whether performed on single or paired samples, cannot be used to reliably establish, confirm, or exclude a diagnosis of R equi pneumonia in foals.
Publication Date: 2002-09-27 PubMed ID: 12322921DOI: 10.2460/javma.2002.221.825Google Scholar: Lookup
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- Comparative Study
- Evaluation Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper evaluates the efficiency of five serologic tests in diagnosing Rhodococcus equi pneumonia in foals before the onset of clinical symptoms and finds none of the tests reliable enough for this purpose.
Objective and Methodology
- The research was conducted with the objective to determine the sensitivity and specificity of five serologic assays used to diagnose Rhodococcus equi pneumonia in foals. The researchers aimed to identify if any of the assays could detect affected foals before any clinical signs manifested, or if they could differentiate between affected and unaffected foals when clinical signs first appeared.
- The study was implemented as a nested case-control study involving 26 foals.
- The researchers collected serum samples from all the foals at three different time periods – 2, 4, and 6 or 7 weeks of age. Additional samples were collected from those foals that showed signs of R equi pneumonia and also from age-matched unaffected foals.
- These samples were then tested with three different types of ELISA (a type of test used to detect and measure antibodies in the blood), an agar gel immunodiffusion assay, and a synergistic hemolysis inhibition assay.
Findings and Conclusions
- The sensitivity and specificity data indicated that none of the assays could reliably differentiate between affected and unaffected foals at any of the testing periods, including the pre-onset phase of the clinical indicators.
- The researchers noted no significant difference between the affected and unaffected foals in terms of the proportion of foals that had an increase in test values between paired samples collected at 4 and 6 or 7 weeks of age.
- For all assays, result values increased significantly over time. However, the rate of increase was not significantly different between the affected and unaffected foals. This means the progression of the disease in affected foals did not significantly alter the rate of test value increase compared to healthy foals.
- In conclusion, the research suggests that serologic assays, whether performed on single or paired samples, cannot reliably establish, confirm, or exclude a diagnosis of R equi pneumonia in foals. The tests were therefore deemed ineffective in reliably diagnosing Rhodococcus equi pneumonia in foals before the onset of clinical signs.
Cite This Article
APA
Martens RJ, Cohen ND, Chaffin MK, Takai S, Doherty CL, Angulo AB, Edwards RE.
(2002).
Evaluation of 5 serologic assays to detect Rhodococcus equi pneumonia in foals.
J Am Vet Med Assoc, 221(6), 825-833.
https://doi.org/10.2460/javma.2002.221.825 Publication
Researcher Affiliations
MeSH Terms
- Actinomycetales Infections / diagnosis
- Actinomycetales Infections / immunology
- Actinomycetales Infections / veterinary
- Animals
- Antibodies, Bacterial / blood
- Case-Control Studies
- Enzyme-Linked Immunosorbent Assay / methods
- Enzyme-Linked Immunosorbent Assay / veterinary
- Hemolytic Plaque Technique / veterinary
- Horse Diseases / blood
- Horse Diseases / diagnosis
- Horse Diseases / immunology
- Horses
- Immunodiffusion / methods
- Immunodiffusion / veterinary
- Pneumonia, Bacterial / diagnosis
- Pneumonia, Bacterial / immunology
- Pneumonia, Bacterial / veterinary
- Rhodococcus equi / immunology
- Rhodococcus equi / isolation & purification
- Sensitivity and Specificity
Citations
This article has been cited 3 times.- Cohen ND, Flores-Ahlschewde P, Gonzales GM, Kahn SK, da Silveira BP, Bray JM, King EE, Blair CC, Bordin AI. Fecal concentration of Rhodococcus equi determined by quantitative polymerase chain reaction of rectal swab samples to differentiate foals with pneumonia from healthy foals. J Vet Intern Med 2022 May;36(3):1146-1151.
- Tirosh-Levy S, Gürbilek SE, Tel OY, Keskin O, Steinman A. Seroprevalence of Rhodococcus equi in horses in Israel. J S Afr Vet Assoc 2017 Jun 26;88(0):e1-e6.
- Shaw SD, Cohen ND, Chaffin MK, Blodgett GP, Syndergaard M, Hurych D. Estimating the Sensitivity and Specificity of Real-Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals. J Vet Intern Med 2015 Nov-Dec;29(6):1712-7.
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