Histoplasmosis is a disease associated with the droppings of bats known as guano. The disease primarily affects the lungs and can be life threatening, particularly to those with a weakened immune system. It is transmitted when a person inhales spores from fungus that grow on bird and bat droppings.

Is dried bat poop dangerous?

Dry guano can harbor histoplasmosis, a fungus. You do not want to get it into your lungs as it may have long-term health consequences. Vacuuming or disturbing old, dry guano could also expose a person doing the removal to histoplasmosis spores.

Can bat poop in attic make you sick?

The problem begins when dried bat guano is disturbed and "bat guano dust" is created in an attic. When these microscopic spores from the dried bat guano are inhaled by humans they can cause a serious respiratory disease called histoplasmosis*.