| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Evaluation Studies |
Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, USDA, Ames, IA 50010, USA. sausterm@nadc.ars.usda.gov
The aim of the study reported here was to estimate the sensitivity and specificity of the gamma interferon (IFN-gamma) ELISA for paratuberculosis in sheep using receiver-operating characteristic analysis. Bacteriologic culture of tissues was used to define the reference positive population (n = 33). Two reference negative populations were used: culture-negative sheep from infected flocks (n = 77), and sheep from noninfected flocks (n = 358). We also evaluated the accuracy of 2 Mycobacterium avium subspecies paratuberculosis (MAP) antigen preparations, a whole-cell sonicate (MpS) and a johnin purified-protein derivative (PPDj). The source of the reference negative sheep used in the analysis affected overall accuracy of the IFN-gamma ELISA. The area under the curve was 0.683 (95% confidence interval 0.574-0.787), using culture-negative sheep from infected flocks, was 0.831 (0.764-0.889), using sheep from noninfected flocks for the MpS, and was 0.809 (0.726-0.881) and 0.897 (0.862-0.925) for the PPDj, respectively. Using the MpS, the cut point that classified the most sheep correctly was an optical density reading of 0.20, for sensitivity of 40.7% (19.4-57.6) and specificity of 88.7% (77.0-95.7) or 97.6% (93.04-99.5), depending on the reference negative population used. Using the PPDj, the cut point that classified the most sheep correctly was 0.25 for sensitivity of 66.7% (47.2-82.7) and specificity of 93.5% (85.5-97.9) or 98.3% (96.4-99.4), respectively. The PPDj was more accurate at identifying MAP-infected sheep than was the MpS (P = 0.034).
This article has been cited by other articles:
|
|
 |
|
  D. J. Begg, K. de Silva, K. Bosward, L. Di Fiore, D. L. Taylor, G. Jungersen, and R. J. Whittington Enzyme-linked immunospot: an alternative method for the detection of interferon gamma in Johne's disease J Vet Diagn Invest, March 1, 2009; 21(2): 187 - 196. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. R. Stabel Pasteurization of Colostrum Reduces the Incidence of Paratuberculosis in Neonatal Dairy Calves J Dairy Sci, September 1, 2008; 91(9): 3600 - 3606. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Suelee. Robbe-Austerman, J. R. Stabel, and D. G. Morrical Skin test and gamma interferon enzyme-linked immunosorbent assay results in sheep exposed to dead Mycobacterium avium subspecies paratuberculosis organisms J Vet Diagn Invest, January 1, 2007; 19(1): 88 - 90. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Semret, D. Bakker, N. Smart, I. Olsen, K. Haslov, and M. A. Behr Genetic Analysis of Mycobacterium avium Complex Strains Used for Producing Purified Protein Derivatives. Clin. Vaccine Immunol., September 1, 2006; 13(9): 991 - 996. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
