Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: 7/9/1998
Publication Date: N/A
Technical Abstract: In this study, we evaluated the single cervical skin test (SCT), comparative cervical skin test (CCT), and blood tuberculosis test (BTB) for diagnosis of tuberculosis (TB) in naturally infected elk. In September, 1997, the SCT was conducted on 55 captive elk of which 17 were classified as SCT suspect. When these were retested using the CCT, 15 were classified as reactors. All 17 elk were euthanized and tissue samples were collected TB was confirmed by isolation of M. bovis or by observation of TB compatible lesions in all 15 CCT reactor elk and in 1 elk that was CCT negative. TB was also confirmed in 2 calves that were not tested. In December, 1997, the 52 remaining elk, including calves not previously tested, were tested using the SCT and BTB. Fifteen elk were classified as reactors and TB was confirmed in 7. In February, 1998, 28 elk were euthanized and tissue samples were collected. Two elk had compatible lesions and M. bovis was isolated from 1 elk with lesions and from 1 elk with no lesions. BTB results for the 52 elk tested in December, 1997, were as follows: 42 were negative; 7 were avian; 2 were equivocal; and 1 was not done. M. bovis was isolated from an elk with no BTB result. Results of this study indicate that skin testing can be used to identify elk infected with M. bovis. None of the infected animals were detected by the BTB test when it was conducted approximately 90 days after the previous skin test. Scientists that developed the BTB recommend that the test be conducted 14 days after skin testing. A provision in the UMR allows for the BTB test to be used when the SCT is conducted in high risk herds. Use of the BTB test for the TB eradication program in Cervidae may need to be reconsidered.