Photo credit: CDC/ CDC-DPDx; Blaine Mathison - This image depicts a view from above of an adult, Cimex lectularius bed bug. Adult bed bugs are on average 5 mm long and have an oval-shaped and flattened body.
The common bed bug (Cimex lectularius) has long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. Unlike most public health pests, bed bugs are not known to transmit or spread disease.
They can, however, cause other public health issues, so it’s important to pay close attention to preventing and controlling bed bugs.
Experts believe the recent increase in bed bugs in the United States may be due to more travel, lack of knowledge about preventing infestations, increased resistance of bed bugs to pesticides, and ineffective pest control practices.
The good news is that there are effective strategies to control bed bugs involving both non-chemical and chemical methods.
Bed bugs can be hard to find and identify, given their small size and their habit of staying hidden. It helps to know what they look like, since the various life stages have different forms.
Appearance of Bed Bugs (Cimex lectularius L.)
Two adult bed bugs in a petri dish (courtesy of Kim Jung)
Adult bed bugs, in general, are:
about the size of an apple seed (5-7 mm or 3/16 - 1/4 inch long);
long and brown, with a flat, oval-shaped body (if not fed recently);
balloon-like, reddish-brown, and more elongated (if fed recently);
a “true bug” (characteristics of true bugs include a beak with three segments; antenna that have four parts; wings that are not used for flying; and short, golden-colored hairs); and
smelly, with a “musty-sweetish” odor produced through glands on the lower side of the body.
Young bed bugs (also called nymphs), in general, are:
smaller, translucent or whitish-yellow in color; and
if not recently fed, can be nearly invisible to the naked eye because of coloring and size.
Bed bug eggs, in general, are:
tiny, the size of a pinhead;
pearl-white in color; and
marked by an eye spot if more than five days old.
Bed Bug Life Cycle
Life cycle of the bed bug. Photo Courtesy of Stephen Doggett, Department of Medical Entomology, Westmead Hospital, Sydney, Australia
The life cycle of a bed bug is shown in the photograph below. During its lifetime, a bed bug will go through the following stages (Starting from the top left, moving counterclockwise):
1st stage nymph (1.5 mm).
2nd stage nymph (2 mm).
3rd stage nymph (2.5 mm).
4th stage nymph (3 mm).
5th stage nymph (4.5 mm).
Unfed adult female.
Unfed adult male.
Looking for Signs of Bed Bugs
Photo of a person's arm with bed bug bites (courtesy of Harold Harlan, AFPMB)
Closeup of blood on a chair (Photo courtesy of Harold Harlan)
A more accurate way to identify a possible infestation is to look for physical signs of bed bugs. When cleaning, changing bedding, or staying away from home, look for:
Rusty or reddish stains on bed sheets or mattresses caused by bed bugs being crushed.
Dark spots (about this size: •), which are bed bug excrement and may bleed on the fabric like a marker would.
Eggs and eggshells, which are tiny (about 1mm) and pale yellow skins that nymphs shed as they grow larger.
Live bed bugs.
Where Bed Bugs Hide
Canvas strap of old box spring covering that is housing adults, skin castings, feces, and eggs. (Photo courtesy of Dr. Louis Sorkin)
When not feeding, bed bugs hide in a variety of places. Around the bed, they can be found near the piping, seams and tags of the
mattress and box spring, and in cracks on the bed frame and headboard.
If the room is heavily infested, you may find bed bugs:
In the seams of chairs and couches, between cushions, in the folds of curtains.
In drawer joints.
In electrical receptacles and appliances.
Under loose wall paper and wall hangings.
At the junction where the wall and the ceiling meet.
Even in the head of a screw.
Since bed bugs are only about the width of a credit card, they can squeeze into really small hiding spots. If a crack will hold a credit card, it could hide a bed bug.
Bed bugs along the side of a window frame
Photo courtesy: Jung Kim
Close up of bed bug eggs on cardboard
Photo courtesy: Harold Harlan
Bed bugs along the bottom edge of an electrical outlet
Bed Bug Behavior and Habit
Understanding the behavior of bed bugs (how they eat, live, and reproduce) will help you to find an infestation before it becomes established and to monitor for the presence of bed bugs after your home has been treated.
Appear to prefer to feed on humans, but will feed on other mammals and birds as well.
Will readily travel 5-20 feet from established hiding places (called harborage) to feed on a host.
Even though they are primarily active at night, if hungry they will seek hosts in full daylight.
Feeding can take 3-12 minutes.
The rusty or tarry spots found on bed sheets or in bug hiding places are because 20% of the time adults and large nymphs will void remains of earlier blood meals while still feeding.
Bed bugs need at least one blood meal before the individual bug can develop to the next of the six life stages.
They can feed more than once.
Each stage also requires the molting of skin.
To continue to mate and produce eggs, both males and females must feed at least once every 14 days.
Each female may lay 1 to 3 eggs per day and 200-500 eggs per her lifetime (6-12 months but could be longer).
Egg-to-egg life cycle may take four to five weeks under favorable conditions.
Bed bugs can survive and remain active at temperatures as low as 7°C (46°F), but they die when their body temperatures reaches 45°C (113°F).
To kill bed bugs with heat, the room must be even hotter to ensure sustained heat reaches the bugs no matter where they are hiding.
Common bed bugs are found almost anywhere their host can live.
Tropical bed bugs (Cimex hemipterus) require a higher average temperature than the common bed bug and are found in tropical and subtropical areas.
Protecting Your Home from Bed Bugs
Bed bugs are great hitchhikers. They can move from an infested site to a new home by traveling on furniture, bedding, luggage, boxes, and clothing.
Although they typically feed on blood every five to ten days, bed bugs can be quite resilient; they are capable of surviving several months to a year without feeding.
A few simple precautions can help prevent bed bug infestation in your home:
Inspect the luggage rack in your hotel room for bed bugs.
Use a protective cover that encases mattresses and box springs and eliminates many hiding spots. The light color of the encasement makes bed bugs easier to see. Be sure to purchase a high quality encasement that will resist tearing and check the encasements regularly for holes.
Reduce clutter in your home to reduce hiding places for bed bugs.
Vacuum frequently to remove any successful hitchhikers.
Be vigilant when using shared laundry facilities. Transport items to be washed in plastic bags (if you have an active infestation, use a new bag for the journey home). Remove from dryer directly into bag and fold at home. (A dryer on high heat can kill bed bugs.)
If you live in a multi-family home, try to isolate your unit by:
Installing door sweeps on the bottom of doors to discourage movement into hallways.
Sealing cracks and crevices around baseboards, light sockets, etc., to discourage movement through wall voids.
Consider purchasing a portable heating chamber to treat any items that you believe may have bed bugs.
Do-it-yourself Bed Bug Control
Identify the Problem
Inspect infested areas, plus surrounding living spaces, to determine extent of infestation.
Consider non-chemical methods of killing bed bugs. Some will be more useful than others.
-Heat treatment using a clothes dryer on high heat, black plastic bags in the sun or a hot, closed car (pest management professionals have other methods that are not suitable for non-trained individuals to use).
-Cold treatment can be successful in the home environment if the freezer is set to 0o F. You must leave the items in the freezer at that temperature for four days. (Always use a thermometer to check the temperature, since home freezers are not always set to 0o.)
Reducing the numbers of bugs with these and other non-chemical methods is helpful, but is unlikely to entirely eliminate the infestation.
If needed, use pesticides carefully according to the label directions or hire a pest management professional.
Look for EPA-registered pesticides.
Bed bugs must be listed on the label.
Use foggers (bug bombs) only with extreme care. Improper use can harm your health or cause a fire/explosion.
Because foggers work with a broadcast spraying action, they should not be used as the sole source of bed bug control. The spray will not reach the cracks and crevices where bed bugs hide.
Every few days after you complete your initial cleanup and control processes, carefully look for any evidence of bed bugs.
If you see bed bugs, that means that either the initial cleanup missed some individuals or that eggs have hatched (finding and removing or killing all eggs can be very difficult) and retreatment may be needed.
Desiccants (drying agents) can be particularly effective in some situations since they work by drying out the bug (which means the bed bugs can't develop resistance to it).
If using desiccants, be sure to use only products registered as a pesticide.
Do not use pool or food-grade diatomaceous earth - this type of diatomaceous earth can harm you when you breathe it in. The pesticide version uses a different size of diatoms, which reduces the hazard.
Desiccants can be very effective; however, they can take up to several months to work.
Bed bug interceptor (place under furniture legs to catch bed bugs)
Evaluate and Prevent
Continue to inspect for presence of bed bugs, at least every 7 days, in case any eggs remained.
Interceptors (placed under the legs of furniture to catch bed bugs and keep them from climbing the legs; commercial and do-it-yourself versions available), traps or other methods of monitoring can be used.