Submitted to: International Conference on Mycobacterium bovis
Publication Type: Abstract only
Publication Acceptance Date: 8/22/2005
Publication Date: 8/22/2005
Citation: Judge, L.J., Waters, W.R., Palmer, M.V., Bolin, S.R. 2005. Population Differences in Test Specificity and Validation of Novel Antigens [abstract]. International Conference on Mycobacterium bovis. p. 70. Interpretive Summary:
Technical Abstract: The Gamma Interferon test (BovigamR) has been utilized by several countries for the diagnosis of bovine Tuberculosis; recently (2003) the United States Department of Agriculture approved the use of this test. Michigan began using this test in 2004 with 2332 tests conducted statewide during the calendar year. Michigan was granted split-state status (April, 2004); this necessitated the development of two distinct testing zones within the state. As a result, Gamma Interferon test performance has been monitored separately in these zones; test specificity has been significantly lower in the lower disease status (bovine Tuberculosis endemic) zone than in the higher status (bovine Tuberculosis disease-free) zone. This is the opposite of the expected result (of reduced specificity where disease prevalence is known to be higher) and has greatly limited the use of the test (high false positive rate) in some areas of the state. Therefore, a validation study for the assessment of novel antigens for use with the Gamma Interferon test (ESAT-6/CFP-10) with the potential for improving test specificity has been initiated. Field validation and subsequent approval of these antigens for use in the United States could greatly facilitate the adoption of the Gamma Interferon test in Michigan. These antigens may also prove to be a useful addition to the BovigamR testing utilized in other states and nations bovine Tuberculosis testing programs.