Histoplasmosis is a systemic disease resulting from inhaled spores affecting which organ primarily?

• A. Lungs
• B. Liver
• C. Kidneys
• D. Brain

Answer: (A)

The main concept is that histoplasmosis starts with inhalation of the fungal spores, so the lungs are the first and primary site of infection. When these spores are inhaled, they settle in the alveoli and are taken up by macrophages, triggering a pulmonary immune response and granuloma formation. While the disease can become systemic and involve other organs such as the liver, spleen, bone marrow, and lymph nodes, those organs are affected secondarily after the fungi spread through the reticuloendothelial system. The question asks which organ is primarily affected, and that is the lungs because they’re the initial point of entry and infection.