HISTOPLASMOSIS

infection with the fungus Histoplasma capsulatum, occurring spontaneously in humans and other animals. The disease is contracted by the inhalation of dust containing spores of the fungus. The fungus is believed to flourish in soil that is contaminated by the droppings of chickens, pigeons, starlings, or bats. The chief site of infection is the lungs, though the fungus can spread through the bloodstream to other organs such as the liver. There are three forms of the disease. The primary acute form involves only the lungs and causes symptoms of fever, coughing, and chest pain. The infection may be slight and is often asymptomatic. In the progressive disseminated form of histoplasmosis, the infection spreads to the liver, spleen, or adrenal glands, where it causes lesions and damages those organs. In the third form, chronic cavitary disease, the infection remains in the lungs but damages them more seriously, causing coughing and severe shortness of breath. All three forms can produce the characteristic symptoms of coughing, chest pain, difficulty in breathing, fever, chills, and fatigue. Histoplasmosis is worldwide in distribution and is endemic in parts of the central eastern United States and the Mississippi River valley; infants and men past middle age show the least resistance to symptomatic infection, but 5080 percent of the total population of endemic areas show positive skin tests. Treatment with amphotericin B is usually effective.