Guano, urine, odor, and ectoparasites Bat guano and urine accumulating in attics and wall spaces attract arthropods such as roaches and mites. The accompanying odor can be pungent but not dangerous. Bat ectoparasites, such as ticks, mites, fleas, and bugs, rarely attack humans. They are most likely to cause a nuisance after a house has been batproofed, thereby ridding the edifice of bats but leaving arthropods. Arthropod problems are unlikely except in very large, well-established bat colonies where fumigation may be appropriate.
Ectoparasites quickly die in the absence of bats.
House bat management. U.S. Fish and Wildlife Service, Resource Publication 143. Northern Prairie Wildlife Research Center Home Page.