Indoor Air sciences CSMI Practice Exam

What is a common cause of Histoplasmosis?

1. Bacteria in bat urine

2. Virions in pigeon feces

3. Fungi growing in soil in southwestern US

4. Fungi growing in bird droppings

The correct answer is: Fungi growing in bird droppings

Histoplasmosis is a disease caused by inhaling spores from the fungus Histoplasma capsulatum. This fungus is commonly found in environments where there are large amounts of organic material, particularly in soil that is enriched with bird or bat droppings. The presence of bird droppings creates an ideal substrate for the growth of this fungus. The spores can become airborne when the soil is disturbed, leading to potential inhalation by individuals nearby, putting them at risk of developing the infection. This association with bird droppings, especially from pigeons and other birds, is a well-documented source of Histoplasma spores, making it a key factor in understanding how the disease spreads. By recognizing that the fungus thrives in bird droppings, it becomes clear why this answer is the most accurate in identifying a common cause of Histoplasmosis.