Histoplasmosis is an infection transmitted by airborne spores that you breathe in when you work in or around soil that contains a fungus called Histoplasma capsulatum. It generally affects your lungs, but may spread to other organs or tissues outside your lungs.
Farmers, landscapers, construction workers and people who have contact with bird or bat droppings are especially at risk of histoplasmosis.
Asymptomatic primary histoplasmosis
This is the most common form of histoplasmosis and usually causes no signs or symptoms in otherwise healthy people who become infected. The only sign that you were ever infected may be small scars in the lungs.
Most people with histoplasmosis never develop symptoms and aren't aware they're infected. But for some people — primarily infants and those with compromised immune systems — histoplasmosis can be serious. Effective treatments are available for even the most severe forms of histoplasmosis.