Submitted to: Wildlife Disease Association Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 4, 2000
Publication Date: N/A
Technical Abstract: Mycobacterium bovis has been isolated from herds of cattle in northeast Michigan where there is a wildlife reservoir of disease in white-tailed deer. Results of DNA fingerprinting indicate that the deer and cattle are infected with the same strain of M. bovis. The purpose of this study was to determine if cattle can become infected with M. bovis through indirect contact with experimentally infected deer. Three groups of four deer were inoculated with 7 x 10**5 M. bovis by instillation of the organisms into the crypt of the palatine tonsil. After two weeks, pens where the deer were housed were topically disinfected and three groups of three six month old calves were introduced into the barn. Each group of deer was paired with a group of calves. Deer were given excess feed and hay and allowed access to it for several hours. The deer were then moved to a holding pen and the calves were moved to the pen that had been occupied by the deer without cleaning the pen. The calf pens were cleaned and the dee were then moved to the clean pens. This process was repeated daily for 80 days. All of the deer were euthanized by day 91 of the experiment and all had extensive lesions of tuberculosis. On day 77, all of the calves were skin tested using the comparative cervical skin test and were classified as reactors. Results of the interferon gamma assay were positive for three of the calves on day 28 and for all nine calves on day 56. Calves were necropsied beginning on day 177. Gross and microscopic lesions were observed and M. bovis was isolated from all calves. Results of this study show that calves can become infected with M. bovis through indirect contact with experimentally infected white-tailed deer.