Prevalence of Mycobacterium bovis infection in cervids on privately owned ranches

Abstract
Objective—To determine prevalence of tuberculosis caused by infection with Mycobacterium bovis in cervids on privately owned ranches in northeastern lower Michigan. Design—Epidemiologic survey. Animals—Cervids on 96 privately owned ranches. Procedures—A combination of slaughter and skin tuberculin testing was used to collect data. Infection with M bovis was confirmed by use of standard necropsy and bacteriologic culture techniques. Results—Cervids with tuberculosis were detected on 1 of the 96 ranches. The apparent prevalence of tuberculosis in cervids from the 96 ranches was 1.1 cases/100 cervids (21 cases/1,867 cervids tested). For the ranch with infected cervids, prevalence of infection with M bovis was 12.1 cases/100 cervids (21 cases/174 cervids tested). No obvious gross lesions were seen in 8 of 21 white-tailed deer and 1 coyote with culture-confirmed M bovis infection. Conclusions and Clinical Relevance—The lack of visible lesions in a substantial proportion of infected animals should be taken into consideration in studies involving detection and prevalence of tuberculosis. (J Am Vet Med Assoc 2002;220:656–659)