Cats are resistant to infection with M tuberculosis but are susceptible to M bovis, M avium complex, or M microti. Some unclassified bacillus forms have also been isolated. Contaminated milk causing GI tract lesions, typically in the mesenteric lymph nodes, is the most common circumstance, and historically this was responsible for a very high percentage of tuberculous cats in Europe. Rapid, hematogenous dissemination to other organs, including the lungs and regional lymph nodes, can occur. Infected skin or deeper wounds sometimes give rise to tuberculous sinuses. Lesions have a central area of necrosis, usually without calcification. The tuberculin skin test is considered unreliable in cats. Diagnosis may be assisted by radiography, ELISA, and culture of the organism. Affected cats should be euthanized because of public health concerns.
Last full review/revision March 2012 by Charles O. Thoen, DVM, PhD