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Am J Vet Res. 2004 Nov;65(11):1483-9.

Investigation of the transmission of Mycobacterium bovis from deer to cattle through indirect contact.

Author information

1
Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, USDA, 2300 Dayton Ave, Ames, IA 50010, USA.

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.

ANIMALS:

24 11-month-old, white-tailed deer and 28 6-month-old, crossbred calves.

PROCEDURE:

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 AND CLINICAL RELEVANCE:

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.

PMID:
15566085
[Indexed for MEDLINE]

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