Histoplasma is described as a fungus that lives in which environment?

• A. In soil with large amounts of animal droppings; common in the Ohio Valley.
• B. In standing water with algae growth.
• C. In indoor air conditioning ducts.
• D. On tree bark in rainy regions.

Answer: (A)

Histoplasma capsulatum is a soil-dwelling fungus that thrives in soil enriched with bird or bat guano. In warm, humid regions, this soil supports its growth, and when the soil is disturbed, its spores become airborne and can be inhaled, leading to infection. That makes soil with large amounts of animal droppings, particularly in areas like the Ohio Valley, the best description of its environment. The other options don’t reflect Histoplasma’s usual niche: standing water with algae suggests an aquatic environment, indoor air ducts point to different indoor molds, and tree bark in rainy regions isn’t the typical Histoplasma habitat.