@barbb MAC stands for mycobacterium avium complex . It is considered to be a rare lung disease . Unlike TB it is not considered a contagious disease. It is usually treated with three strong antibiotics for at least a year. Generally a person will have a bronchoscopy, CT scan, blood work checks, and periodic sputum checks during the MAC journey. Most people have the MAC bacteria but are not infected with it. When it becomes an infection it becomes problematic. irene5