Naturally occurring, or so-called spontaneous tuberculosis in rabbits is an uncommon finding; most cases are caused by Mycobacterium bovis or M avium. Rabbits apparently become infected when exposed to other tuberculous animals or by ingesting milk from tuberculous cattle. M avium has been reported in rabbits that are housed in close contact with domestic or exotic birds infected with M avium. Rabbits are relatively resistant to M tuberculosis; such infections are seldom reported. Rabbits infected with M avium complex may develop miliary lesions involving the lung and liver. Tuberculin skin tests may be conducted on the skin of the abdomen. Test sites should be observed for induration and swelling at 24 and 48 hr after injection of M bovis purified protein derivative.