At a magnification of 1125X, this photomicrograph revealed some of the ultrastructural morphology exhibited by a Histoplasma capsulatum fungal macroconidium. The reproductive spores produced by H. capsulatum can be either macroconidia or microconidia. It is the macroconidia that exhibits finger-like projections from its surface, whereas, the microconidia are much smaller, round, and possess a smooth surface. See PHIL 299 for a depiction of both macro- and microconidia
What is histoplasmosis?
Histoplasmosis is a disease caused by the fungus Histoplasma capsulatum. Its symptoms vary greatly, but the disease primarily affect the lungs. Occasionally, other organs are affected. This form of the disease is called disseminated histoplasmosis, and it can be fatal if untreated.
What are the symptoms of histoplasmosis?
Most infected persons have no apparent ill effects. The acute respiratory disease is characterized by respiratory symptoms, a general ill feeling, fever, chest pains, and a dry or nonproductive cough. Distinct patterns may be seen on a chest x-ray. Chronic lung disease resembles tuberculosis and can worsen over months or years. The disseminated form is fatal unless treated.
Is histoplasmosis treatable?
Yes. Antifungal medications are used to treat severe cases of acute histoplasmosis and all cases of chronic and disseminated disease. Mild disease usually resolves without treatment. Past infection results in partial protection against ill effects if reinfected.
Where is H. capsulatum found?
H. capsulatum is found throughout the world and is endemic in certain areas of the United States. The fungus has been found in poultry house litter, caves, areas harboring bats, and in bird roosts.
Credit: CDC/ Dr. Libero Ajello