Bed bugs, Cimex lectularius, have been around for thousands of years. They are a human parasite (organism living in, with, or on another organism) from the insect family Cimicidae, which thrives in temperate and tropical regions worldwide. Bed bugs are exclusively hematophagous (they feed only on blood). They are small but visible to the naked eye, wingless, yellow to reddish brown in color, oval shaped, and have prominent eyes. They can hide in the cracks and crevices of mattresses, in box springs, on the backboards of beds, and behind loose wallpaper baseboards, and they can travel in furniture, luggage, clothing, and other personal belongings. The stigma commonly associated with bed bugs is mostly unwarranted because infestation is not necessarily attributable to lack of hygiene. International travel, immigration, and resistance to insecticides have contributed to a resurgence in reports of infestations with these insects in developed countries. Bed bugs are predominantly night feeders, attracted to warm-blooded animals, including humans. There is currently no scientific evidence that these blood-sucking insects spread diseases such as human immunodeficiency virus (HIV). The April 1, 2009, issue of JAMA includes an article about bed bugs.