Pigs are susceptible to M tuberculosis, M bovis, and M avium complex. M avium avium is most frequently isolated; serologic identification of isolates is useful in epidemiologic investigations. Granulomatous lesions are most often found in the cervical, submandibular, and mesenteric lymph nodes, but lesions may also be found elsewhere. Typically, enlarged nodes contain small, white or yellow, caseous foci, usually without any evidence of mineralization. Pigs with disease due to M tuberculosis may have similar regionalized lesions. Pigs are particularly susceptible to M bovis, which is usually acquired from shared grazing or ingestion of dairy products. This can cause a rapidly progressive, disseminated disease with caseation and liquefaction of lesions. The SID test conducted on the dorsal surface of the ear is useful for diagnosis.
Last full review/revision March 2012 by Charles O. Thoen, DVM, PhD