Tuberculosis in cattle caused by IS901+ Mycobacterium avium subsp. avium -a case report

In small cattle herd an eight-year-old cow showed a reaction to bovine tuberculin in two consecutive skin tests. The animal showing clinical signs related to tuberculin was slaughtered for diagnostic purpose. The lungs were completely coverred with disseminate tubercles of different sizes and the mediastinal lymph nodes were enlarged. Pneumonia granulomatosa tuberculosa and lymphadenitis hyperplastica chronica were diagnosed histologically.Mycobacterium avium susp.avium of IS901+ and IS1245+ genotype was also isolated from lungs and from lymph node. Six weeks after the affected animal has been eliminated from the herd, the skin test in other animals on the farm was performed: single test with avian tuberculin in extensively poultry (n=12), comparative test with bovine and avian tuberculin in catlle (n=7). Concluding from the results of negative skin testing of other animals on the farm, it is very likely that the cow did not transmit M.a. avium into the environment.