Bed bugs are in the insect family Cimicidae and include
three species that attack people. Of these, the most
important is Cimex lectularius, which may also bite bats,
birds, and rodents.
Cimex lectularius is a cosmopolitan species, most
frequently found in the northern temperate climates of
North America, Europe, and Central Asia. It occurs more
sporadically in southern temperate regions. In Florida and
tropical regions it is replaced by C. hemipterus. Problems
with bed bug infestations used to be quite severe, but with the use of DDT after World War II the
incidence of these pests has been greatly reduced, although infestations still do occur. Currently this insect can be a pest wherever sanitary conditions are primitive, or if there are birds or mammals nesting on or near a house. Crowded and dilapidated housing can also facilitate the insect's movement between residences.