HEALTH HAZARDS ASSOCIATED BAT DROPPINGS
Health risks from bats are often exaggerated. Nevertheless, large populations of roosting bats may present
the risk of disease to people nearby. The most serious health risks arise from disease organisms that can grow in the nutrient-rich
accumulations of bat droppings and debris under a roost — particularly if roosts have been active for years. External
parasites also may become a problem when infested bats leave roosts or nests. The parasites then can invade buildings and
Histoplasmosis is caused by a fungus (Histoplasma capsulatum) found primarily in the areas drained by the
Mississippi and Ohio rivers. Both humans and animals can be affected. The disease is transmitted to humans by airborne fungus
spores from soil contaminated by pigeon and starling droppings (as well as from the droppings of bats). The soil under a roost
usually has to have been enriched by droppings for two years or more for the disease organism to reach significant levels.
Although almost always associated with soil, the fungus has been found in droppings (particularly from bats) alone, such as
in an attic.
Infection occurs when spores, carried by the air are inhaled — especially after a roost has been
disturbed. Most infections are mild and produce either no symptoms or a minor influenza- like illness. On occasion, the disease
can cause high fever, blood abnormalities, pneumonia and even death. In some areas, including portions of Illinois, up to
80 percent of the population show evidence of previous infection. Outbreaks of histoplasmosis have occurred in Central Illinois.
The National Institutes of Health (NIH) has reported a potentially blinding eye condition — presumed
ocular histoplasmosis syndrome (OHS) — that probably results from the fungus. NIH estimates that 4 percent of those
exposed to the disease are at risk of developing OHS.
Bats and disease
Bats are associated with a few diseases that affect people, such as rabies and histoplasmosis. Rabies is
a dangerous, fatal disease, but only about 5 percent of bats submitted for testing are infected with the rabies virus. In
recent years, there has been increased concern about the risk of rabies transmission following contact with bats. If an injured
or ill bat is found in or around a structure, it should be removed. Because most bats will try to bite when handled, they
should be picked up with tongs or a shovel. (please contact us or your local animal control officer) If a bat has bitten or
scratched a person or pet or is found in your home, capture the bat without touching it with your hands and without crushing
its head. If the bat is dead, refrigerate it (DO NOT freeze) and then contact your local health department immediately for
Bats with rabies have been identified in most areas of the state. In recent years, bats have been the most
common animal identified with rabies in the state.
The incidence of histoplasmosis being transmitted from bat droppings to humans is not thought to be high.
Nevertheless, fresh bat droppings (unlike fresh bird dropping) can contain the histoplasmosis fungus. Bat droppings do not
need to come into contact with soil to be a source of the disease.
Removal and cleanup of bird and bat droppings
If there is a SMALL accumulation of droppings from a few birds or bats, it can be cleaned up with soap