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Awake to the Growing Bed Bug Problem - December 2005
December 15, 2005
UNIVERSITY PARK, PA - A dramatic resurgence of bed bugs is causing alarm across the country, but an expert at Penn State says that by following preventative steps, homeowners can stop bed bugs in their tracks.
Bed bugs were once a common public health pest worldwide, but were mostly eradicated by DDT after World War II. Entomologists at Penn State are blaming their recent re-emergence on increased immigration from the developing world, the advent of cheap international travel and the reluctance of some people to utilize spray insecticides within buildings. Other possible causes include the reuse of second-hand furniture and mattresses.
According to Steve Jacobs, extension entomologist at Penn State, bed bugs are small, wingless insects that feed solely upon the blood of warm-blooded animals. "The common bed bug prefers human hosts, but will feed on domestic birds and other animals when necessary," he says. "There are various species that inhabit bird nests and bat roosts and await the return of their hosts, while others live in people's homes."
Bed bugs are active only at night, usually just before dawn. During the day they hide in cracks and crevices in walls, floors, beds and furniture. "When only a few bed bugs are present, they live close to human sleeping areas; when numerous, they can be found in many rooms of the house," Jacobs explains.
The critical first step in determining if you have a bed bug infestation is correctly identifying them. According to Jacobs, adult bed bugs are chestnut brown and flat and oval in shape. "Adults are tiny, about 1/4 inch long. Their small, flat shape enables them to readily hide in cracks, however their bodies become elongated, swollen, and dark red after a blood meal. Newly hatched nymphs look much like the adults but are smaller and nearly colorless," he explains.
Female bed bugs can lay up to 350 eggs in a lifetime, depositing them on rough surfaces or in crack and crevices. "The eggs hatch in six to 17 days, with nymphs needing a blood meal in order to grow. Bed bugs reach maturity after about 21 days, but may take longer if food is scarce," Jacobs explains. "In fact, nymphs and adults can live up to one year without food. When you consider three or more generations can occur each year, with each generation living 12-18 months, you can see how an infestation can quickly become severe," says Jacobs.
People are often fearful that bed bugs can transmit diseases, but according to Jacobs there have been no documented cases of disease transmission as a result of bites. However, their bites can produce an itching, irritating rash. "Bed bugs bite by using their sharp beak to pierce the skin and then inject a salivary fluid containing an anticoagulant that helps them obtain blood," Jacobs explains. "They feed rapidly, becoming engorged in less than ten minutes. The act of biting is usually not felt, but later there is an allergic reaction to the protein found in the bed bug's saliva and a colorless lump develops at the bite location with discomfort lasting a week or more. Rows of three or so welts on exposed skin are characteristic signs of bed bugs."
Besides the bites, another indication of a bed bug infestation is the blood stains from crushed bugs or rusty brown spots of excrement that can be found on sheets and mattresses, bed clothes, and walls. "Fecal spots, eggshells, and shed skins may be also be found in the vicinity of their hiding places," says Jacobs. "An offensive, sweet, musty odor from their scent glands may be detected when bed bug infestations are severe, but the smell is not always detected."
Once you determine you have a bed bug infestation, control can be achieved by following an integrated pest management (IPM) approach that involves tactics that are safe and environmentally compatible, including preventive measures, sanitation, and chemicals applied to targeted sites.
Prevent bed bugs from gaining a foothold in your home by keeping infested items out of it. It is important to carefully inspect clothing and baggage of travelers, being on the lookout for bed bugs and their telltale fecal spots. Jacobs says you should also thoroughly inspect your home, looking for bed bugs and their harborage sites so that cleaning efforts and insecticide treatments can be targeted. "Be sure to inspect mattresses, box springs, and bed frames, as well as crack and crevices that bed bugs may hide in during the day or when digesting a blood meal. The latter sites include window and door frames, floor cracks, carpet tack boards, baseboards, electrical boxes, furniture, pictures, wall hangings, drapery pleats, loosened wallpaper, cracks in plaster, and ceiling moldings," he explains. For hotels, apartments and other multiple-type dwellings, you should have adjoining units inspected since bed bugs can travel long distances.
According to Jacobs, sanitation measures include frequently vacuuming the mattress and premises, laundering bedding and clothing in hot water, and cleaning and sanitizing dwellings. After vacuuming, immediately place the vacuum cleaner bag in a plastic bag, seal tightly, and discard in a container outside. This prevents captured bed bugs from escaping into the home. A stiff brush can be used to scrub the mattress seams to dislodge bed bugs and eggs. Discarding the mattress is another option, although a new mattress can quickly become infested if bed bugs are still in the home. Steam cleaning of mattresses generally is not recommended because it is difficult to get rid of excess moisture, which can lead to problems with mold, mildew, house dust mites, etc.
After the mattress is vacuumed or scrubbed, it can be enclosed in a zippered mattress cover such as that used for house dust mites. Any bed bugs remaining on the mattress will be trapped inside the cover. Leave the cover in place for a year or so since bed bugs can live that long without a blood meal. Sticky traps or glueboards may be used to capture bed bugs, however they are typically utilized to determine if bed bugs are present, not as a method to eliminate the bugs.
Insecticides can be applied as spot treatments to cracks and crevices where bed bugs are hiding. Botanical insecticides containing natural pyrethrins will repel insects and can 'knock down' bed bugs for a period of time, but natural pyrethrins quickly deteriorate, tend to scatter the bugs, and do not provide the necessary residual action of some other materials. Finishes on furniture and other wood items may be damaged from the petroleum carriers contained in aerosol pyrethrins. Inorganic materials such as silica gel, boric acid and diatomaceous earth will provide long-term control provided they are used in an environment with low humidity. These inorganic materials have very low repellency, have a long residual life, and can provide good control if thoroughly applied to cracks and crevices.
If insecticides are used, they should be applied properly to reduce the risk of exposure. "Avoid using highly repellent formulations, which cause bed bugs to scatter to many places. Dust formulations may be used to treat wall voids and attics. You may have to repeat applications if bed bugs are present two weeks after the initial treatment," says Jacobs. Also, keep in mind there are no insecticides labeled for use on bedding or linens. These items should be dry cleaned or laundered in hot water and dried using the "hot" setting. A professional pest control company may be needed to eliminate the bugs. "Experienced companies know where to look for bed bugs, are schooled in proper techniques, and have an assortment of management tools at their disposal," Jacobs explains.
For more information on bed bugs and their control, go the Pennsylvania IPM Program's Pest Problem Solver at http://paipm.cas.psu.edu/ProblemSolvers/PHealthProblSolv.htm, or go to http://www.ento.psu.edu/extension/factsheets/bed_bugs.htm.
The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and nonagricultural situations. For more information, contact the program at (814) 865-2839, or visit Web site http://paipm.cas.psu.edu. To view our archived news releases, see Web site http://paipm.cas.psu.edu/newsrelease.html.