Mycobacteria other than mammalian tubercle bacilli are capable of producing disease in a wide range of animal hosts. Serotypes of Mycobacterium avium complex cause the most important mycobacterial diseases in domestic animals. Although disease is most common in lymph nodes, a wide variety of tissues may be involved, including tissue from spleen, liver, lungs, kidney, central nervous system, gall bladder, intestinal mucosa, skeletal system, ovaries, and the skin.