Pulmonary histoplasmosis is an infection caused by a fungus called Histoplasma capsulatum. Parts of the fungus, called spores, are inhaled into the lungs. This fungus can be found in soil or other material with bird or bat droppings. In the United States, it is most common in the Mississippi and Ohio River valleys. People who have serious problems with this disease are:
- Babies
- Young children
- Older adults
- People with long-term lung problems or weak immune systems