I want to know about the fungal pneumonia blastomycosis. How do you contract it? Is it treatable?

A.H.C.

Blastomycosis is an uncommon fungal infection that usually affects the lungs but can spread to the skin, bones and in rare cases the brain and spinal cord. The organism, named Blastomyces, is known as a "geographic fungus," because people become infected only in the regions where the fungus grows. In North America, Blastomyces is found along major river valleys, including Southeastern and South Central states, Midwestern states bordering the Great Lakes, and other regions near rivers. Cases have also been seen in Africa, Asia, and Central and South America.

Blastomycosis is similar to tuberculosis in that it is not usually diagnosed at the time of infection. When the patient first is exposed to the fungus, he or she may develop a nondescript flulike illness that gets better without treatment. Later, if the fungus reactivates, the patient develops what is called "typical blastomycosis." This is a chronic pneumonia, with cough, fever, shortness of breath, weight loss and chest pain.

If untreated, blastomycosis can sometimes spread rapidly to other organs. It is especially aggressive in patients with weakened immune systems. In other cases, untreated disease progresses slowly, over many months.

Without therapy, infection results in death more often than not. With treatment, however, the vast majority of patients survive. Treatment is usually one of two medications given for six months -- intravenous amphotericin B (trade name Amphotec) or itraconazole (trade name Sporanox) tablets. The oral medicine has an obvious advantage because of the ease of treatment. In addition, intravenous amphotericin B can cause kidney damage. However, if a patient is especially ill, amphotericin B is the preferred choice until he or she is stable and can begin oral treatment.