Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 5/21/2000
Publication Date: N/A
Technical Abstract: Mycobacterium bovis is a member of the M. tuberculosis (TB) complex and can cause TB in a broad range of host species including humans. Although TB caused by M. bovis has nearly been eradicated from domestic livestock in the United States, the disease continues to be a serious problem in many regions of the world. Food-producing animals infected with M. bovis pose a public health threat because of the potential for human consumption of mea or milk products that are contaminated with the organism. The purpose of our study was to determine the risk of infection associated with consumption of meat contaminated with M. bovis. Swine have been used as an animal model to study a variety of human diseases. Results of our previous research demonstrated that swine are susceptible to M. bovis when challenged by the intratracheal, intratonsilar, intravenous, intragastric, and oral routes of inoculation. The distribution and characteristics of lesions produced in swine experimentally challenged with M. bovis are very similar to lesions observed in humans with TB. In the present study, swine were challenged by the oral route with various doses of M. bovis. We determined that swine become infected when they are fed uncooked ground beef or PBS that contains between 1.2 x 10*2 and 5.7 x 10*7 M. bovis organisms. Infection was confirmed by histologic examination and bacteriologic culturing. Evidence of infection was observed in tissues collected from the head, thoracic and abdominal cavities, and carcass of swine challenged with M. bovis by the oral route. Results of this study indicate that swine, when used as an animal model of human TB, can become infected with M. bovis by ingestion of food products contaminated with as few as 120 organisms.