Bed bugs, bed-bugs, or bedbugs are parasitic insects of the cimicid family that feed exclusively on blood. Cimex lectularius, the common bed bug, is the best known, as it prefers to feed on human blood. Other Cimex species specialize in other animals, e.g., bat bugs, such as Cimex pipistrelli (Europe), Cimex pilosellus (western US), and Cimex adjunctus (entire eastern US).
The name “bed bug” derives from the preferred habitat of Cimex lectularius: warm houses and especially nearby or inside of beds and bedding or other sleep areas. Bed bugs are mainly active at night, but are not exclusively nocturnal. They usually feed on their hosts without being noticed.
A number of adverse health effects may result from bed bug bites, including skin rashes, psychological effects, and allergic symptoms. They are not known to transmit any pathogens as disease vectors. Certain signs and symptoms suggest the presence of bed bugs; finding the insects confirms the diagnosis.
Bed bugs have been known as human parasites for thousands of years. At a point in the early 1940s, they were mostly eradicated in the developed world, but have increased in prevalence since 1995, likely due to pesticide resistance. Because infestation of human habitats has been on the increase, bed bug bites and related conditions have been on the rise as well.
Bed bugs can cause a number of health effects, including skin rashes, psychological effects, and allergic symptoms. They can be infected by at least 28 human pathogens, but no study has clearly found that the insect can transmit the pathogen to a human being. Bed bug bites or cimicosis may lead to a range of skin manifestations from no visible effects to prominent blisters.
Diagnosis involves both finding bed bugs and the occurrence of compatible symptoms. Treatment involves the elimination of the insect and measures to help with the symptoms until they resolve. They have been found with methicillin-resistant Staphylococcus aureus (MRSA) and with vancomycin-resistant Enterococcus faecium (VRE), but the significance of this is still unknown.
Investigations into potential transmission of HIV, MRSA, hepatitis B, hepatitis C, and hepatitis E have not shown that bed bugs can spread these diseases. However it may be possible that arboviruses are transmissible.
Adult bed bugs are light brown to reddish-brown, flattened, oval-shaped and have no hind wings. The front wings are vestigial and reduced to pad-like structures. Bed bugs have segmented abdomens with microscopic hairs that give them a banded appearance. Adults grow to 4–5 millimetres (0.16–0.20 in) long and 1.5–3 millimetres (0.059–0.118 in) wide.
Newly hatched nymphs are translucent, lighter in color and become browner as they moult and reach maturity. A bed bug nymph of any age that has just consumed a blood meal has a bright red translucent abdomen, fading to brown over the next several hours, and to opaque black within two days as the insect digests its meal. Bed bugs may be mistaken for other insects, such as booklice, small cockroaches, or carpet beetles; however, when warm and active their movements are more ant-like and, like most other true bugs, they emit a characteristic disagreeable odor when crushed.
Bed bugs use pheromones and kairomones to communicate regarding nesting locations, feeding and reproduction.
The life span of bed bugs varies by species and is also dependent on feeding.
Bed bugs can survive a wide range of temperatures and atmospheric compositions. Below 16.1 °C (61.0 °F), adults enter semi-hibernation and can survive longer; they can survive for at least five days at −10 °C (14 °F), but die after 15 minutes of exposure to −32 °C (−26 °F). Common commercial and residential freezers reach temperatures low enough to kill most life stages of bed bug, with 95% mortality after 3 days at −12 °C (10 °F). They show high desiccation tolerance, surviving low humidity and a 35–40 °C range even with loss of one-third of body weight; earlier life stages are more susceptible to drying out than later ones.
The thermal death point for Cimex lectularius is 45 °C (113 °F); all stages of life are killed by 7 minutes of exposure to 46 °C (115 °F). Bed bugs apparently cannot survive high concentrations of carbon dioxide for very long; exposure to nearly pure nitrogen atmospheres, however, appears to have relatively little effect even after 72 hours.
Bed bugs can exist singly, but tend to congregate once established. Though strictly parasitic, they spend only a tiny fraction of their life cycles physically attached to hosts. Once a bed bug finishes feeding, it relocates to a place close to a known host, commonly in or near beds or couches in clusters of adults, juveniles, and eggs—which entomologists call harborage areas or simply harborages to which the insect returns after future feedings by following chemical trails. These places can vary greatly in format, including luggage, inside of vehicles, within furniture, amongst bedside clutter—even inside electrical sockets and nearby laptop computers. Bed bugs may also nest near animals that have nested within a dwelling, such as bats, birds, or rodents. They are also capable of surviving on domestic cats and dogs, though humans are the preferred host of Cimex lectularius.
Bed bugs can also be detected by their characteristic smell of rotting raspberries. Bed bug detection dogs are trained to pinpoint infestations, with a possible accuracy rate of between 11% and 83%.
Photo By Content Providers(s): CDC/ Harvard University, Dr. Gary Alpert; Dr. Harold Harlan; Richard Pollack. Photo Credit: Piotr Naskrecki (http://phil.cdc.gov/phil) [Public domain], via Wikimedia Commons