Sex
Mortality/morbidity
Frequency: United States
Frequency: International
Age
The rates of positive results on skin testing for sensitivity to antigens of H capsulatum are similar in males and females. Rheumatologic manifestations tend to occur predominantly in females.
Histoplasmosis is the most common endemic fungal infection seen in humans. The central river valleys in the midwestern and south central United States are endemic for histoplasmosis. Approximately 250,000 individuals are infected annually. Clinical manifestations of histoplasmosis occur in less than 5% of the population. Most infections are sporadic, although large outbreaks of histoplasmosis may occur.
Although histoplasmosis can affect individuals of any age, those in extreme age ranges are more prone to developing infection as a result of immature or deteriorated immune defenses.
Approximately 90% of patients with acute pulmonary histoplasmosis are asymptomatic. Acute pericarditis can occur in as many as 5% of patients who are symptomatic. The pericardial fluid is generally exudative. Pleural effusions develop in 40-60% of patients with pericarditis.
The fungus is predominantly found in river valleys between latitudes 45° north and 30° south in South and Central America.
