@spencersok I live in Michigan in the summer and Tucson in the winter. When I was diagnosed with MAC, my Infectious Disease doc told me that it's very unusual to see MAC in Michigan, and thinks I got it in Arizona, which is terribly dry. @windwalker (Terri M), wrote in a comment to me in the "New Diagnosis of MAC/MAI & I'm scared" thread: "I caught my mac in Tucson, Az. pretty sure from our hot tub. Arizona is one of our country's 'Hot Spots' for mac. Some other states are: Florida, California, Wisconsin, Hawaii, and I think New Hampshire. Well water is supposed to be void of mac in most cases." @sueinmn wrote: "according to my doc, and the reading I have done, the bacterium is endemic in MANY places – in fact, just about everywhere. I too was diagnosed after several winters in South Texas and Arizona – and several bouts of what appeared to be desert fever or valley fever."