Histoplasmosis is a fungal infection caused by inhaling spores from the Histoplasma capsulatum fungus, which is commonly found in soil, especially in areas with bird or bat droppings. Most people who breathe in these spores do not get sick, but some may develop flu-like symptoms, such as fever, cough, and fatigue. In healthy individuals, the body often fights off the infection without treatment. However, those with weakened immune systems, such as people with HIV/AIDS or those undergoing chemotherapy, may experience more severe symptoms and complications. Early diagnosis and treatment are important for managing the infection effectively.