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Journal of clinical microbiology1997; 35(9); 2215-2219; doi: 10.1128/jcm.35.9.2215-2219.1997

Comparison of PCR and culture to the indirect fluorescent-antibody test for diagnosis of Potomac horse fever.

Abstract: Potomac horse fever is an acute systemic equine disease caused by Ehrlichia risticii. Currently, serologic methods are widely used to diagnose this disease. However, serologic methods cannot determine whether the horse is presently infected or has been exposed to ehrlichial antigens in the past. The purpose of the present study was to compare the sensitivities of the nested PCR and cell culture with that of the indirect fluorescent-antibody (IFA) test for the diagnosis of Potomac horse fever. Blood and fecal specimens serially collected from a pony experimentally infected with E. risticii Maryland, blood specimens serially collected from mice inoculated with E. risticii Ohio 380, and blood and/or fecal specimens collected from 27 horses which had clinical signs compatible with Potomac horse fever were examined. These horses resided in Kentucky, Indiana, Pennsylvania, and Vermont. The IFA test titer became positive after 6 days postinoculation (p.i.) for the pony. A culture of the blood of the pony was positive for E. risticii starting on day 1 and was positive through day 28 p.i. By the nested PCR, E. risticii was detectable in the blood and feces of the pony starting on day 1 and was detectable through day 32 p.i. E. risticii was detected in the blood of subclinically infected mice by the nested PCR. Twenty-two clinical specimens were seropositive for E. risticii by the IFA test, with titers ranging from 1:20 to 1:1,280. E. risticii was cultured from 95% (20 of 21) of seropositive clinical blood specimens. E. risticii was detected in the blood by PCR in 81% (17 of 20) of the culture-positive clinical specimens. The study indicated that the nested PCR is as sensitive as culture for detecting infection with E. risticii.
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Publication Date: 1997-09-01 PubMed ID: 9276390PubMed Central: PMC229942DOI: 10.1128/jcm.35.9.2215-2219.1997Google Scholar: Lookup
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  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research paper seeks to determine the most efficient method for diagnosing Potomac Horse Fever. Through a comparison exercise, the study analyzes the efficacy of Nested Polymerase Chain Reaction (PCR), cell culture, and the indirect fluorescent antibody (IFA) test in diagnosing this disease.

Research Context

  • Potomac Horse Fever is an acute equine disease, instigated by an organism known as Ehrlichia risticii.
  • In this study, various diagnostic modalities have been compared to identify their sensitivities towards the detection of the disease.
  • The techniques tested include the nested PCR, cell culture, and the indirect fluorescent antibody (IFA) test.
  • The researchers utilized blood and fecal specimens which were collected on different times from a pony which was deliberately infected with E. risticii. They also used blood specimens from mice inoculated with the same organism and samples from 27 horses showing symptoms of Potomac Horse Fever.

Research Analysis

  • The researchers noted that the IFA test started to show a positive outcome on the sixth day following the pony’s inoculation.
  • E. risticii could be also detected in the pony’s blood culture from the first day to the 28th day post-inoculation.
  • The nested PCR test was successful in detecting E. risticii in the blood and feces from the first day and until the 32nd day post-inoculation.
  • Subclinically infected mice also returned positive results for E. risticii through the nested PCR method.

Study Conclusion

  • Of the 27 horses exhibiting Potomac Horse Fever symptoms, 22 showed positive outcomes in the IFA test. The test results ranged from 1:20 to 1:1,280.
  • Out of the 21 seropositive clinical blood specimens, E. risticii was obtained from 95% of the samples via culturing.
  • 81% of these culture-positive clinical specimens showed presence of E. risticii through a PCR test.
  • The results of the study therefore indicate that the nested PCR test is just as sensitive as cell culture in detecting E. risticii infections.

Cite This Article

APA
Mott J, Rikihisa Y, Zhang Y, Reed SM, Yu CY. (1997). Comparison of PCR and culture to the indirect fluorescent-antibody test for diagnosis of Potomac horse fever. J Clin Microbiol, 35(9), 2215-2219. https://doi.org/10.1128/jcm.35.9.2215-2219.1997

Publication

Journal of clinical microbiology
ISSN: 0095-1137
NlmUniqueID: 7505564
Country: United States
Language: English
Volume: 35
Issue: 9
Pages: 2215-2219

Researcher Affiliations

Mott, J
  • Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210-1093, USA.
Rikihisa, Y
    Zhang, Y
      Reed, S M
        Yu, C Y

          MeSH Terms

          • Animals
          • Cells, Cultured
          • DNA, Bacterial / analysis
          • DNA, Bacterial / genetics
          • Ehrlichia / genetics
          • Ehrlichia / growth & development
          • Ehrlichia / immunology
          • Ehrlichiosis / blood
          • Ehrlichiosis / diagnosis
          • Ehrlichiosis / veterinary
          • Feces / microbiology
          • Female
          • Fluorescent Antibody Technique, Indirect / methods
          • Horse Diseases / diagnosis
          • Horse Diseases / microbiology
          • Horses
          • Leukocytes, Mononuclear / microbiology
          • Mice
          • Polymerase Chain Reaction / methods
          • Sensitivity and Specificity

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