Bed bugs are parasitic insects from the genus Cimex, who are micropredators that feed on blood, usually at night.[7] Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms.[5] Bed bug bites may lead to skin changes ranging from small areas of redness to prominent blisters.[1][2] Symptoms may take between minutes to days to appear and itchiness is generally present.[2] Some individuals may feel tired or have a fever.[2] Typically, uncovered areas of the body are affected.[2] Their bites are not known to transmit any infectious disease.[5][7][8] Complications may rarely include areas of dead skin or vasculitis.[2]
Bed bug bites are caused primarily by two species of insects: Cimex lectularius (the common bed bug) and Cimex hemipterus, found primarily in the tropics.[3] Their size ranges between 1 and 7 mm.[7] They spread by crawling between nearby locations or by being carried within personal items.[2] Infestation is rarely due to a lack of hygiene but is more common in high-density areas.[2][9] Diagnosis involves both finding the bugs and the occurrence of compatible symptoms.[5] Bed bugs spend much of their time in dark, hidden locations like mattress seams, or cracks in a wall.[2]
Treatment is directed towards the symptoms.[2] Eliminating bed bugs from the home is often difficult, partly because bed bugs can survive up to approximately 300 days without feeding.[6][8] Repeated treatments of a home may be required.[2] These treatments may include heating the room to 50 °C (122 °F) for more than 90 minutes, frequent vacuuming, washing clothing at high temperatures, and the use of various pesticides.[2]
Fossils found in Egypt show bed bugs have been known as human parasites for at least 3,500 years.[10] Despite being nearly eradicated in developed countries after WW2, infestations have increased since the 1990s and bed bugs are now relatively common in all regions of the globe.[7][3][4][6] Experts point to several factors that have contributed to the explosion in infestations over the last three decades: increased immigration and international travel; expanded markets for second-hand goods; a greater focus on control of other pests; and both the banning of effective pesticides and increased resistance to pesticides still in use.[4][11][12]