Mycobacterium avium-intracellulare infection (MAI) is an atypical mycobacterial infection caused by Mycobacterium avium complex. This infection causes respiratory illness in birds, pigs, and humans, especially in immunocompromised people. In the later stages of AIDS it can be very severe. It usually first presents as a persistent cough. It is typically treated with a series of three antibiotics for a period of at least six months.