ARS | Publication request: Bovine tuberculosis in a Nebraska herd of farmed elk and fallow deer: a failure of the tuberculin skin test and opportunities for serodiagnosis

Submitted to: Veterinary Medicine International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2011
Publication Date: April 17, 2011
Citation: Waters, W.R., Stevens, G.E., Schoenbaum, M.A., Orloski, K.A., Robbe-Austerman, S., Harris, N.B., Hall, S.M., Thomsen, B.V., Wilson, A.J., Brannian, R.E., Nelson, J.T., Schafer, S., Esfandiari, J., Dutton, M., Greenwald, R., Lyashchenko, K.P. 2011. Bovine tuberculosis in a Nebraska herd of farmed elk and fallow deer: a failure of the tuberculin skin test and opportunities for serodiagnosis. Veterinary Medicine International [serial online]. 2011:Article 953985. Available: http://www.sage-hindawi.com/journals/vmi/2011/953985/.

Interpretive Summary: Elk and fallow deer are routinely tested for tuberculosis by tuberculin skin testing as outlined in the USDA uniform methods and rules for the eradication of bovine tuberculosis in the United States. However, skin testing has an apparent lack of accuracy and requires two handling events, often injurious to these animals. New tests for routine surveillance of tuberculosis in elk and fallow deer are greatly needed. In the present study, it was determined skin test is poorly sensitive in the detection of tuberculosis in elk and fallow deer. Additionally, three antibody based blood tests demonstrated exceptional accuracy. This case study demonstrates new technologies capable of detecting tuberculosis in captive deer species. Since this technology is easily transferred to diagnostic laboratories, serological assays may prove practical for use in surveillance of tuberculosis infection in captive elk and fallow deer. These methods should prove useful for the tuberculosis eradication program.

Technical Abstract: In 2009, Mycobacterium bovis infection was detected in a herd of 59 elk (Cervus elaphus) and 50 fallow deer (Dama dama) in Nebraska, USA. Upon depopulation of the herd, the incidence of bovine tuberculosis (TB) was estimated at ~71 - 75%, based upon histopathology and culture results. Particularly with elk, gross lesions were often severe and extensive. One year prior, the majority of the elk had been tested for TB by single cervical test (SCT) and all were negative. Upon initial detection of a tuberculous elk in this herd, 44 of the 59 elk were tested by SCT; only 3 / 28 M. bovis-infected elk were detected by SCT (sensitivity ~ 11%). Serum samples were collected from the infected elk (n = 34, all SCT negative) and fallow deer (n = 32, none tested by SCT) from this herd at necropsy and tested by three antibody detection methods including MultiAntigen Print Immunoassay, CervidTB STAT-PAK, and Dual Path Platform VetTB. Serologic test sensitivity ranged from 79 - 97% depending on the test format and host species. Together, these findings demonstrate the opportunities for use of serodiagnosis in the rapid detection of TB in elk and fallow deer.