Author
Palmer, Mitchell | |
Waters, Wade | |
Whipple, Diana |
Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/1/2004 Publication Date: 11/20/2004 Citation: Palmer, M.V., Waters, W.R., Whipple, D.L. 2004. Deer to cattle transmission of mycobacterium bovis through indirect contact. American Journal of Veterinary Research. 65(11):1483-1489 Interpretive Summary: To demonstrate infection through oral exposure, calves received either high or low oral doses of the bacterium Mycobacterium bovis, while 2 positive control calves received intratonsilar doses of M. bovis. Calves were examined 133 days after oral or intratonsilar exposure. To demonstrate deer to cattle transmission, deer were experimentally inoculated with M bovis. On a daily basis, calves either switched pens with deer (phase I) or feed was moved from inoculated deer pens to the calf pens (phase II). Switching of pens continued for 90 days while sharing of feed continued for 140 days after which deer and calves were examined. Three of four calves receiving the low oral dose and 1 of 4 calves receiving the high oral dose developed tuberculosis. In phase I, 9 of 9 (100%) calves developed tuberculosis while in phase II, 4 of 9 (44%) calves developed tuberculosis. Experimentally infected deer can transmit M. bovis to cattle through sharing of feed. Livestock producers in areas where tuberculosis is endemic in free-ranging white-tailed deer should implement management practices to prevent access of wildlife to feed intended for livestock. Technical Abstract: To demonstrate infection through oral exposure, crossbred bovine calves received oral doses of either 4.3 x 10**6 colony forming units (CFU) of M bovis (n=4, high dose) or 5 x 10**3 CFU (n=4, low dose), while 2 positive control calves received intratonsilar doses of 1.7 x 10**5 CFU. Calves were euthanatized and examined 133 days after oral or intratonsilar exposure. To demonstrate deer to cattle transmission, deer were experimentally inoculated with 4 to 7 x 10**5 CFU of M bovis (n=12 for each phase). On a daily basis, calves (n=9 for each phase) either switched pens with deer (phase I) or feed was moved from inoculated deer pens to the calf pens (phase II). Switching of pens continued for 90 days while sharing of feed continued for 140 days after which deer and calves were examined. Tissues were collected for bacteriologic culture and microscopic examination. Three of four calves receiving the low oral dose and 1 of 4 calves receiving the high oral dose developed tuberculosis. In phase I, 9 of 9 (100%) calves developed tuberculosis while in phase II, 4 of 9 (44%) calves developed tuberculosis. Experimentally infected deer can transmit M bovis to cattle through sharing of feed. Livestock producers in areas where tuberculosis is endemic in free-ranging white-tailed deer should implement management practices to prevent access of wildlife to feed intended for livestock. |