Bats are a very important part of the environment. They serve a important role in keeping the night flying insect population in check, especially mosquitoes. Although they can be a very important species, they can also have some harmful effects if they choose to roost in our homes or other buildings. An accumulation of bat feces (known as guano) can cause property damage and be quite a health risk if the dust is inhaled. In addition, bats are also carriers of several types of diseases, such as rabies. So sometimes it is necessary to relocate these animals to a more appropriate location and prevent them from returning again.
If an exclusion is done correctly, it is 100% bat proof. However, it is quite an extensive process. All holes around the house as small as the diameter of a dime must be sealed and one-way chutes must be affixed to the house at the entrance/exits. This allows them to safely leave for the night to fed but prevents them from getting back into the roost. When they cannot gain access, they will leave and find a new roost area instead.
Depending on the severity of infestation there can be a fair amount of damage and Guano, we provide safe removal of soiled areas. Health Risks relating to Bats Histoplasmosis is an airborne disease caused by a microscopic fungus that occurs in soil and in the nitrogen-rich droppings of birds and bats (Tuttle and Kern 1981, Greenhall 1982, Fenton 1992). A dry cough and other flu-like symptoms are the usual signs of histoplasmosis, which is often mistaken for influenza. While histoplasmosis often does not produce any symptoms, severe symptoms such as high fever, problems with vision, and life-threatening complications occasionally do occur.
The above information is an excerpt from an excellent booklet "Guide to Northeastern Bats and Bat Problems."