ARS | Publication request: Update on vaccination of white-tailed deer with Mycobacterium bovis BCG: Safety and Efficacy

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2010
Publication Date: November 15, 2010
Citation: Palmer, M.V., Thacker, T.C., Waters, W.R. 2010. Update on vaccination of white-tailed deer with Mycobacterium bovis BCG: Safety and Efficacy [abstract]. American Association of Veterinary Laboratory Diagnosticians. p. 122.

Technical Abstract: In 1994, white-tailed deer in northeast Michigan were found to be harboring Mycobacterium bovis, the causative agent of tuberculosis in most animals including humans. Although deer likely contracted tuberculosis from cattle in the early 20th century, when the disease was present in Michigan cattle, today disease is spilling back from deer to cattle. Efforts have been made to decrease disease in deer in that region. One possible tool would be to decrease disease transmission through vaccination of deer. The human tuberculosis vaccine M. bovis BCG has been used in humans since 1920. BCG does not induce disease in humans; however, exposure to BCG may interfere with tuberculin skin testing resulting in false positive results. In deer, BCG vaccination decreases disease severity. As venison is often consumed by hunters, it is important to recognize potential public health issues resulting from possible exposure to BCG remaining in deer tissues. BCG persisted for 3 months and 9 months in deer vaccinated orally or subcutaneously, respectively. However, persistence was not seen in meat or other areas that may be used for food. Vaccinated deer shed BCG vaccine for an undetermined time. Non-vaccinated pen mates can be exposed to BCG. Vaccine shedding to other species, such as cattle, could confound tuberculosis testing in cattle, creating false positive results. It was demonstrated that BCG vaccinated deer shed vaccine to pen mates, but did not shed vaccine to cattle that were exposed to deer indirectly through shared feed. Mycobacterium bovis BCG is likely to be a safe and efficacious vaccine for free-ranging white-tailed deer.