Submitted to: International Workshop on Tuberculosis in Animals
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 1999
Publication Date: N/A
Technical Abstract: In 1997 tuberculosis was diagnosed in a captive herd of white-tailed deer in northeast Michigan. The herd was composed of approximately 350 deer on 1500 acres, and was operated as a private hunting establishment. The decision to depopulate the herd was made by the owner, the Michigan Department of Agriculture, and the USDA. During the depopulation effort, postmortem examinations were done on 116 deer. Various tissues, feces, an swabs of the nasal, oral, and tonsillar crypt regions were collected for bacteriologic culture from all 116 deer. Tissues were collected for microscopic examination from deer with gross lesions suggestive of tuberculosis. Tuberculosis lesions were seen in 9 of 116 deer. Mycobacterium bovis was isolated from 1 deer that had no gross lesions of tuberculosis. The most common sites to contain gross lesions were the medial retropharyngeal lymph nodes (6 of 9), and the lung (4 of 9). Three of ten tuberculosis deer would have been missed had the examination been limited to the head and associated cranial lymph nodes. Swabs of the tonsilar crypt from 1 of 116 deer contained M. Bovis. All other swabs and fecal samples were negative for the presence of M. Bovis. Pelleted feed, corn, hay, and soil were collected for bacteriologic culture from feeding sites on the 1500-acre premise. Water was collected for bacteriologic culture from ponds used as watering sites. Mycobacterium bovis was not isolated from any feed, hay, soil, or water samples. Some surveys for tuberculosis in white-tailed deer involve examination of the head and cranial lymph nodes only. These results suggest that examination of the head alone, will underestimate the prevalence of disease in a naturally infected population.