Which fungal infection is endemic to certain regions of the United States and can cause severe respiratory illness in immunocompromised patients?

Histoplasmosis is a fungal infection caused by the organism Histoplasma capsulatum, which is endemic to regions of the United States, particularly in areas near the Ohio and Mississippi River Valleys. The organism is found in soil, often associated with bird and bat droppings. When the spores are inhaled, particularly in immunocompromised individuals, they can lead to severe respiratory illness, including pneumonia and disseminated disease.

In immunocompromised patients, such as those with HIV/AIDS, cancer, or even those on immunosuppressive medications, the ability to mount an effective immune response is decreased. This makes them more susceptible to severe manifestations of diseases like histoplasmosis. The infection can range from mild and asymptomatic to severe and life-threatening, depending on the immune status of the individual.

While other fungal infections listed, like candidiasis and aspergillosis, also affect immunocompromised individuals, they are not endemic to specific regions of the United States in the same way histoplasmosis is. Candidiasis is commonly associated with opportunistic infections in a variety of clinical settings rather than being tied to geographic locations. Cryptococcus is another significant pathogen that can cause severe illness, especially in immunocompromised patients,