Bed bugs in a mattress (click on picture to enlarge)

 

Bed bugs feeding
on a persons skin

Close-up picture
of a bed bug
 

Inspections and treatments must be very thorough. (M. Potter, Univ. of Kentucky)
 

 Photo shows eggs, nymphs, and adults beneath carpet edge. (M. Potter, Univ. of Kentucky)
 

Bed bugs hidden beside a recessed screw under a nightstand. (M. Potter, Univ. of Kentucky)

Bed bugs often congregate along seams of mattresses and box springs. Blackish spots are excrement. (M. Potter, Univ. of Kentucky)

Bed Bugs are Back!
(Integrated Pest Management, Cornell Cooperative Extension)

Chinches Domesticas
(Texas Cooperative Extension)

 

Cimex lectularius, the common bed bug.

Bed Bug bites on an arm

Bed Bug bites on the back of a person

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Description and Habits
Bed bugs are small, brownish, flattened insects that feed solely on the blood of animals. The common bed bug, Cimex lectularius, is the species most adapted to living with humans. It has done so since ancient times.

Adult bed bugs are about 1/4 inch long and reddish brown, with oval flattened bodies.  The immature (nymphs) resemble the adults, but are smaller and somewhat lighter in color.  Bed bugs do not fly, but can move quickly over floors, walls, ceilings and other surfaces.  Female bed bugs lay their eggs in secluded areas, depositing up to five a day and 500 during a lifetime.  The eggs are tiny, whitish, and hard to see without magnification (individual eggs are about the size of a dust spec).  When first laid, the eggs are sticky, causing them to adhere to surfaces.  Newly hatched nymphs are no bigger than a pinhead.  As they grow, they molt (shed their skin) five times before reaching maturity. A blood meal is needed between each successive molt.  Under favorable conditions (70 - 90 degrees F), the bugs can complete development in as little as a month, producing three or more generations per year.  Cool temperatures or limited access to a blood meal extends the development time.  Bed bugs are very resilient.  Nymphs can survive months without feeding and the adults for more than a year.  Infestations therefore are unlikely to diminish by leaving premises unoccupied.  Although C. lectularius prefers feeding on humans, it will also bite other warm-blooded animals, including pets.

Bed bugs are typically active at nighttime, with a maximum attack period about an hour or two before sunrise, though given the chance, they may try to feed at other times throughout the day. Attracted by warmth and the presence of CO2, the bug penetrates the skin of its host with two hollow injector tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, while the other tube withdraws the blood from its host. After a five minute blood meal, the bug returns to its hiding area. The bites can’t usually be felt until a few minutes or hours later. Although bed bugs can live for up to 20 months without a meal, they usually look for blood every five to ten days. They can be found on wooden slats, springs as well as the bed frame. They can also live in wallpaper crevices, electrical wall plates, light fixtures, wall hangings, cabinetry as well as carpet fibers and wooden floorboards. For their size, common household bed bugs are extremely fast.

Characteristically these areas are marked by dark spotting and staining, which is the dried excrement of the bugs.  Also present will be eggs and eggshells, molted skin of maturing nymphs, and the bugs themselves.

Another likely sign of bed bugs is rusty or reddish spots of blood on bed sheets or mattresses.  Heavy infestations are sometimes accompanied by a "buggy" or sweetish odor, although such smells are not always apparent.

Bed bugs prefer to hide close to where they feed.  However if necessary, they will crawl more than 100 feet to obtain a blood meal.  Initial infestations tend to be around beds, but the bugs eventually may become scattered throughout a room, occupying any crevice or protected location. They also can spread to adjacent rooms or apartments.

Bites and Concerns
Bed bugs usually bite people at night while they are sleeping.  They feed by piercing the skin with an elongated break through which they withdraw blood.  Engorgement takes about three to 10 minutes, yet the person seldom knows they are being bitten.  Symptoms thereafter vary with the individual.  Some people develop an itchy welt or localized swelling, while others have little or no reaction.  Unlike fleabites that occur mainly around the ankles, bed bugs feed on any bare skin exposed while sleeping (face, neck, shoulder, arms, hands, etc.) The welts and itching are often attributed to other causes such as mosquitoes.  For these reasons, infestations may go a long time unnoticed, and can become quite large before being detected. 

A common concern with bed bugs is whether they transmit diseases.  Although bed bugs can harbor pathogens in their bodies, transmission to humans is considered highly unlikely.  For this reason, they are not considered a serious disease threat.  Their medical significance is mainly limited to the itching and inflammation from their bites.

How Infestations Originate
The bugs are efficient hitchhikers and are usually transported in on luggage, clothing, beds furniture, etc. Outbreaks can often be traced to international travel from countries where the bugs are common, such as Asia, Africa, Europe, the Caribbean, or Central/South America. This is a particular problem for hotels, motels, and apartments, where turnover of occupants is constant.  Bed bugs are small, escaping detection after crawling into suitcases, boxes, and belongings.  The eggs are almost impossible to see when laid on most surfaces.  Purchase or rental of secondhand mattresses, box springs, and furniture is another way that the bugs are transported into non-infested dwellings.

Once bed bugs are introduced, they often spread room to room throughout the building. Unlike cockroaches that feed on filth, the level of cleanliness has little to do with most bed bug infestations.  Pristine homes, hotels, and apartments have plenty of hiding places and an abundance of warm-blooded hosts.

Controlling Infestations
Bed bugs are challenging pests to control.  They hide in many tiny places, so inspections and treatments must be thorough.  In most cases, it will be prudent to enlist the services of a professional pest control firm.  Experienced companies know where to look for bed bugs, and have an assortment of management tools at their disposal. Owners and occupants must remove excess clutter, and in some cases infested mattresses and box springs.  Since bed bugs can move from room to room, it may be necessary to inspect adjoining rooms and apartments.

Where They Hide
Bed bugs can live in almost any crevice or protected location. The most common place to find them is the bed. Bed bugs often hide within seams, tufts, and crevices of the mattress, box spring, bed frame and headboard.

A thorough inspection requires dismantling the bed and standing the components on edge. Things to look for are the bugs themselves, and the light-brown, molted skins of the nymphs.  Dark spots of dried bed bug excrement are often present along mattress seams or wherever the bugs have resided.  Oftentimes the gauze fabric underlying the box spring must be removed to gain access for inspection and possible treatment.  Bed bugs also hide among items stored under beds.

Many areas besides beds, however, can harbor bed bugs.  Nightstands and dressers should be emptied and examined inside and out, then tipped over to inspect the woodwork underneath. Oftentimes the bugs will be hiding in cracks, corners, and recesses.  Upholstered chairs and sofas should be checked, especially seams, tufts, skirts, and  crevices beneath cushions.  Sofas can be major bed bug hotspots when used for sleeping. 

Treatment Procedures
It often takes hours to properly inspect and treat bed bug infestation, and follow-up visits are usually required.

As mentioned earlier, owners and occupants have important pre-treatment responsibilities.  Reducing clutter is a necessity.  Belongings strewn about rooms afford many places for bed bugs to hide, and impedes inspection and treatment.  Infested bedding and garments will need to be bagged and laundered (120 degrees F minimum), or discarded since these items cannot be treated with insecticides.  Smaller items that cannot be laundered can sometimes be de-infested by heating.  Individual items, for example, can be wrapped in plastic and placed in a hot, sunny location for at least a few days (the 120 degree F minimum target temperature should be monitored in the centermost location with a thermometer). Bed bugs also succumb to cold temperatures below 32 degrees F, but the chilling period must be maintained for at least two weeks.  Vacuuming can be very useful for removing bugs and eggs from mattresses, carpet, walls and other surfaces.  Pay particular attention to seams, tufts and edges of mattresses and box springs, and the perimeter edge of wall-to-wall carpets. Afterward, dispose of the vacuum contents in a sealed trash bag.  Steam cleaning of carpets is also helpful for killing bugs and eggs that vacuuming may have missed.

Adapted from Department of Entomology, University of Kentucky
Pictures courtesy of M. Potter, University of Kentucky