Submitted to: World Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: June 2, 1999
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 lof 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 6 of 7 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 7 deer. Similarly, M. bovis was isolated from nasal secretions 63 days after inoculation from 1 of 7 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. Transmission of M. bovis to uninfected penmates occurred withing 70 days of commingling. Intratonsilar inoculation with M. bovis results in lesions similar to those seen in natural infection. Shedding of M. bovis in saliva and nasal secretions represents a likely route of transmission of disease from deer to deer, as well as to other animals, including humans.