The major health concern associated with bat guano is histoplasmosis. This airborne disease originates in a fungus that is found living in bat droppings. It can affect the respiratory system of any human who breathes in air that has been exposed to it. The body is typically capable of fighting this disease, however, individuals with a compromised immune system may require medication for treatment.
Bats often choose to roost in the attics and open rafters of homes and barns. They sleep during the day, hunt at night, and can create extensive nests by mating and bearing young after a few seasons. The bat guano they leave behind, both inside the upper areas of the home and on the ground outside, is very toxic to humans if disturbed.
Histoplasmosis can live on top of bat guano, or in soil that has been exposed to droppings. When the guano is stirred up in any way, the fungus quickly becomes airborne. It can circulate into the breathable air of a home or building, and infect the lungs of any individual who inhales it.
The disease typically requires a period of around ten days to germinate and begin evidencing symptoms. Sufferers tend to complain of fever, chest pains, coughing, headache, and a loss of appetite. The body's immune system is generally capable of fighting off the disease and experiencing a full recovery in a matter of several weeks. Those with compromised immune systems, such as individuals who are already ill from another disease or have been infected with AIDS, may require treatment including medication and hospitalization.
Many countries, including the US, protect bats as an endangered species, and do not allow them to be exterminated during the removal process. Homeowners may wish to contact a professional exterminator who can completely remove the infestation without killing the animals. They should immediately seal any remaining openings to the home's attic or rafters once this has been completed to prevent the animals from returning. Some of these services also charge a fee for the removal of the animals' waste.
Bat guano is only toxic if disturbed, and will dissipate on its own harmlessly into the air if left untouched after two to three years. If the infestation occurred in a part of the home that can be sealed off from occupants, or in a rarely used outbuilding, then it may be beneficial not to remove the droppings at all. Most cases of illness from exposure to this type of waste occur after a nest or soil near a nest has been cleaned and removed. If a homeowner prefers to clean the area, he should wear a face mask that can filter particles as small as one milli-micron. He should use a vacuum with a high-efficiency air filter to remove the waste and discard of it immediately in a sealed garbage bag.