DEPARTMENT OF COMPARATIVE PATHOBIOLOGY
Catherine Alinovi, DVM,
MS
Graduate Student in Epidemiology/Public Health
Department of Comparative Pathobiology
Purdue University
“Real-Time PCR, Compared To Liquid And Solid Culture Media And ELISA,
For The Detection Of Mycobacterium avium subsp. paratuberculosis”
Thursday, March 27, 2008
VPTH
112
3:30
pm
Abstract:
Fecal and serum samples collected from two subpopulations of
dairy cows in northern Indiana
were used to evaluate sensitivity and specificity of a newly licensed real-time
PCR test for direct fecal detection of Mycobacterium
avium ssp. paratuberculosis (MAP). Results of the real-time PCR were evaluated
in parallel with solid and liquid media culture systems and a serum ELISA for
detection of MAP antibodies. A total of
143 samples were evaluated by all 4 test methods. Using prior published estimates for
sensitivity and specificity of each of the tests and Bayesian methodology, the
sensitivity and specificity of the real-time PCR test was estimated to be 0.60
and 0.97, respectively. The accuracy of
real-time PCR was comparable to both solid and liquid culture. Because real-time PCR accuracy is comparable
to standard culture methods, it is a useful new test. In addition, test results are obtained as
rapidly as an ELISA, but are more accurate than the ELISA. This makes real-time PCR an attractive test
and should shorten the quarantine period required for new purchases of unknown
MAP-status animals into herds participating in an MAP control program.