Macroscopic lesions suggestive of tuberculosis in swine lymph nodes caused by mycobacteria were already described in many countries, including Brazil. This survey was performed in a farm with previous diagnostic of tuberculosis: lymph nodes were obtained from 146 pigs, aged between 2.5 and > 14 months, and after macroscopic and microscopic examination they were cultured. Furthermore feed, water and sawdust were cultured. Macroscopic lesions were characterized as nodes with diameter between 1-2 mm, with a pale yellow, loose, caseous content. Lymph nodes from 12 pigs were positive for acid-fast bacteria. Mycobacterium-group III (Runyon) was isolated in four cases. The lesions occurred mainly in pigs aged between 6 and 7 months old. The same mycobacteria were isolated from sawdust. It is concluded that sawdust might be the source of infection.
Lymph nodes; Swine; Straw; Tuberculosis; Mycobacterinum
