Which organism is often found in bat excrement and can cause respiratory illness?

Histoplasma capsulatum is a fungus that is commonly associated with bat excrement and can cause respiratory illness, particularly histoplasmosis. This organism thrives in environments where bat droppings accumulate, such as caves or old buildings. When contaminated dust or droppings are disturbed, spores can become airborne and inhaled, leading to respiratory infections.

Histoplasmosis can present with various symptoms, from mild respiratory issues to severe pneumonia, depending on the individual's immune status and the extent of exposure. The association with bat feces is significant because it serves as a natural reservoir for the spores of this fungus, making it a key environmental factor in the risk of infection.

Other organisms listed, while they can cause respiratory issues, do not have the same specific relationship with bat excrement. Aspergillus is a mold often found in environments like decaying vegetation but is not specifically tied to bats. Cryptococcus is typically associated with pigeon droppings and can cause respiratory infections as well, but its link to bats is less direct. Valley fever, or coccidioidomycosis, is caused by Coccidioides species and is typically found in soil, particularly in arid regions, rather than in bat droppings.