Infection of swine with Mycobacterium bovis as a model of human tuberculosis.

Swine were infected with Mycobacterium bovis to develop a model for pulmonary and disseminated tuberculosis in humans. Pigs were inoculated with various doses of M. bovis by intravenous (i.v.), intratracheal (int), or tonsillar routes. Animals were euthanized between 17 and 60 days after inoculation, and tissues were collected for culture and histopathologic examination. Lesions of disseminated tuberculosis were found in pigs given 10(4) or 10(8) cfu of M. bovis i.v. or int; localized pulmonary disease was found in pigs given 10(2) or 10(3) cfu of M. bovis int. Lesions ranged from well-organized tubercles with coagulative necrosis, epithelioid macrophages, and fibrosis to large expansive tubercles with liquefactive necrosis and extracellular growth of M. bovis. Tuberculous meningitis was observed in animals given M. bovis i.v. Swine infected with M. bovis are a useful animal model for elucidating the mechanisms of pathogenesis and host defense to tuberculosis in humans.