Histoplasmosis; chronic pulmonary
Definition:
A chronic respiratory
infection caused by inhaling the spores
of the fungus, Histoplasma capsulatum, found in bird and bat
droppings common along river valleys.
Causes, incidence, and risk factors:
Histoplasmosis is caused by a fungus in the central and
eastern United States (Mississippi and Ohio river valleys),
eastern Canada, Mexico, Central America, South America, Africa,
and Southeast Asia. Most cases are mild or without symptoms
(asymptomatic). Acute
histoplasmosis may occur in epidemics. The illness may
last for 1 to 6 months but is rarely fatal.
Progressive and chronic
disease can also occur. In chronic disease, illness occurs
years after exposure to the disease and is usually confined
to the lungs. Scar-like (fibrotic) changes occur within the
lung tissue.
Risk factors include travel or residence in central or eastern
U.S.; environmental or occupational exposure to droppings
of chickens, bats, blackbirds; pre-existing COPD
(chronic obstructive pulmonary
disease); and people whose immune systems have been suppressed
by disease or medication. The incidence
is 5 out of 1,000,000 people.
Updated Date: 02/09/00
Updated By:J. Gordon Lambert, MD, Associate Medical Director,
Utah Health Informatics and adam.com
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