The trend in the prevalence of bovine tuberculosis (BTB) in Korean dairy cattle was investigated in relation to test programs used between 1961 and 2004, during which a total of 8,961,061 dairy cows were tested and 10,248 confirmed to have BTB. The annual prevalence increased in the late 1960s, then decreased during the 1970s and 1980s, and started to increase again from the late 1990s. It seemed that the prevalence varies according to the different test program used. The prevalence of BTB was higher when the tests were performed with heat-concentrated synthetic medium (HCSM) or purified protein derivative (PPD) tuberculin alone compared to that when using combined HCSM and PPD tuberculin testing.

Comparative studies of histopathologic lesions from 23 purified protein derivative (PPD) positive cattle, 21 slaughter cattle found with tuberculosis, and 11 tuberculosis-positive elk (Cervus elaphus) were performed. PPD positive cattle did not show specific histopathologic lesions in all 23 heads that were no visible lesion reactor. Slaughter cattle found with tuberculosis revealed microscopically classical granulomatous lesion (tubercle) with central caseous necrosis surrounded by mantle of epithelioid cells and Langhan's giant cells capsuled by connective tissue in lung. Elk was noted with some different lesion patterns with classical granulomatous lesion and suppurative abscesses that was composed of fibrin, degenerated cells without having connective tissue. In addition, many Langhan's giant cells infiltration in alveoli at peripheral lesion were observed in some cases of classical granulomatous lesion and suppurative abscesses.