Submitted to: North American Deer Farmers Annual Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/24/1998
Publication Date: N/A
Technical Abstract: Tuberculosis caused by Mycobacterium bovis has recently been detected in free-ranging, white-tailed deer in Michigan. Presence of a wild reservoir of tuberculosis is a serious threat to the bovine TB eradication effort. Eradication of TB in white-tailed deer will require a better understanding of disease pathogenesis, diagnosis, and transmission. We developed a model of natural infection using intratonsilar inoculation of white-tailed deer with M. bovis. Routes of transmission were evaluated by culture of nasal, oral, tonsilar, and rectal swabs. M. bovis was isolated from tonsilar swabs from 8 of 9 deer at various times 14 to 87 days after inoculation. M. bovis was isolated from saliva 63 and 80 days after inoculation from 1 of 9 deer. Similarly, M. bovis was isolated from nasal secretions 63 days after inoculation from 1 of 9 deer. Deer were euthanatized and examined 87 days after inoculation. Tuberculous lesions were seen most commonly in medial retropharyngeal lymph nodes and lung, but also involved distant lymphoid and nonlymphoid organs. Intratonsilar inoculation with M. bovis results in lesions similar to those seen in natural infection. M. bovis persists in tonsilar crypts and can shed in saliva and nasal secretions. Relative to intratonsilarly inoculated cattle, deer develop rapid disseminated disease and may, therefore, be more susceptible to M. bovis infection than cattle.