What's in Your Pipes?

That can't be the whole answer, of course, since plenty of Americans take showers without getting sick. Studies show that nearly half of NTM patients are also genetically predisposed to lung infections. Some have inherited one of the genes for cystic fibrosis. Others have a defective alpha-1 anti-trypsin gene, a condition that has been linked to a high risk of emphysema. Perhaps it is a combination of bad genes and bad luck that is making people sick.

Things seem to be getting worse. Several doctors report that more and more of their NTM patients are infected with so-called rapid growers--mycobacteria that are particularly destructive and hard to treat. No one knows why.

One thing is certain: most people with NTM infections are not getting properly diagnosed. Their complaints tend to be general and vague: long-lasting fatigue and a cough that won't go away. A specialized sputum test can identify the infection--if one is ordered. Telltale signs will also show up on a CAT scan--if you know what to look for. That is why doctors and patients are trying to spread the word about this mysterious ailment. (Leitman's husband Philip has taken the lead in Florida, raising funds, organizing medical workshops and creating a website, www.ntminfo.com. Sometimes what you don't know can hurt you.

--With reporting by Michael Peltier/Tallahassee and Mary Sutter/Miami