title: Investigation of the transmission of Mycobacterium bovis from deer to cattle through indirect contact.
abstract: OBJECTIVE
  To investigate the infection of calves with Mycobacterium bovis through oral exposure and transmission of M. bovis from experimentally infected white-tailed deer to uninfected cattle through indirect contact.
  
  
  METHODS
  24 11-month-old, white-tailed deer and 28 6-month-old, crossbred calves.
  
  
  METHODS
  In the oral exposure experiment, doses of 4.3 x 10(6) CFUs (high dose) or 5 x 10(3) CFUs (low dose) of M. bovis were each administered orally to 4 calves; as positive controls, 2 calves received M. bovis (1.7 x 10(5) CFUs) via tonsillar instillation. Calves were euthanatized and examined 133 days after exposure. Deer-to-cattle transmission was assessed in 2 phases (involving 9 uninfected calves and 12 deer each); deer were inoculated with 4 x 10(5) CFUs (phase I) or 7 x 10(5) CFUs (phase II) of M. Bovis. Calves and deer exchanged pens (phase I; 90 days' duration) or calves received uneaten feed from deer pens (phase II; 140 days' duration) daily. At completion, animals were euthanatized and tissues were collected for bacteriologic culture and histologic examination.
  
  
  RESULTS
  In the low- and high-dose groups, 3 of 4 calves and 1 of 4 calves developed tuberculosis, respectively. In phases I and II, 9 of 9 calves and 4 of 9 calves developed tuberculosis, respectively.
  
  
  CONCLUSIONS
  Results indicated that experimentally infected deer can transmit M. bovis to cattle through sharing of feed. In areas where tuberculosis is endemic in free-ranging white-tailed deer, management practices to prevent access of wildlife to feed intended for livestock should be implemented.
authors.affiliation: Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, USDA, 2300 Dayton Ave, Ames, IA 50010, USA.
authors.forename: Mitchell V
authors.initials: MV
authors.lastname: Palmer
authors.forename: W Ray
authors.initials: WR
authors.lastname: Waters
authors.forename: Diana L
authors.initials: DL
authors.lastname: Whipple
mesh_terms: D000821:Animal Feed / Q000382:microbiology; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology* / Q000635:transmission; D003670:Deer / Q000382:microbiology*; D006799:Housing, Animal; D007371:Interferon-gamma / Q000276:immunology; D009163:Mycobacterium bovis; D014374:Tuberculin Test; D014376:Tuberculosis / Q000635:transmission* / Q000662:veterinary*
chemical_list: D007371:Interferon-gamma