Prevalence of atypical mycobacteriosis in slaughtered swine in Gunma Prefecture and the serovars of the isolates.

Atypical mycobacteriosis was detected in 4,919 (0.28%) of 1,776,294 swine slaughtered at the G slaughter house in Gunma Prefecture during the period 1988-1990. The tuberculous lesions were mainly observed in the submaxillary (64.4%) and mesenteric lymph nodes (29.0%). The enzootic and sporadic infections were detected in 4 and 870 of 1,200 piggeries, respectively. Of the 2,076 infected swine detected between September, 1988 and December, 1989, 231 swine were submitted to the isolation of Mycobacterium avium-intracellulare complex (MAIC). MAIC was isolated from 141 of 219 swine that had tuberculous lesions only in the lymph nodes and from all of the remaining 12 swine that had lesions in the liver or in both the lymph nodes and organs. MAIC was also isolated from 11 gastric and 6 cecal contents of the 231 swine. Of 431 strains isolated, 336 were classified into 13 serovars. M. intracellulare serovar 6 (34.6%) was the most predominant, followed by serovars 8 (21.8%), 4 (8.6%) and 10 (6.5%). Four strains (0.9%) were identified as M. avium serovar 3. In 16 swine, each individual harbored plural serovars. The results of the investigation suggested that the atypical mycobacteriosis due to MAIC was widely distributed in swine in Gunma Prefecture.