Guess who is coming to dinner.
For the past month or so, we left the chilly mid-Atlantic region to visit katydids, amblypygids, tarantulas, butterflies, stingless bees, and paper wasps in the tropical rainforests of Central America. As the winter-that-never-was draws to an end we return to North America to meet a few tiny vampires recently in the news. This week we visit despicable bed bugs, tiny bloodsucking fiends recently found in two elementary schools in the District of Columbia. Over the past decade we heard stories of bed bugs appearing in places without beds including office buildings, movie theaters, schools, and retail stores. How do bed bugs work and what is behind this recent upswing in bed bug detections, especially in our major cities?
Like many obligate parasites, bed bugs lead an interesting albeit codependent life. They must have a blood meal in all stages, except eggs, to survive. By inserting tiny sucking mouthparts and pumping in saliva laced with anticoagulants, bed bugs are able to take in several times their weight in blood in a feeding bout lasting from 3 – 10 minutes. They will bite any part of the body including the face, neck, shoulders, arms, and legs. When temperatures are warm, it takes less than a month to complete a generation and when cooler it may take 4 months to complete the life cycle. Like other true bugs, these have scent glands that give them a distinctive odor and a sweet smell sometimes accompanies a heavy infestation.
At three times actual speed, watch as this bed bug tanks up on my blood.
Bed bugs are tough. Nymphs can live several months without a meal and at certain temperatures adults are reported to survive more than a year without food. Females lay 200 to 500 eggs during the course of their lifetime. The eggs are roughly the size of a period at the end of a sentence. The immature stages, the nymphs, are reddish brown when full of blood and tan when empty. Adults are about the size of a peppercorn and brown to chestnut colored when empty or full of blood, respectively. During the day, bed bugs usually hide in bedclothes, mattress seams, box springs, spaces in the bed frame, behind the headboard, baseboards, picture frames, chests of drawers, posters, loose wallpaper, and almost any nook and cranny in the bedroom. I have heard many tales of couches and living room furniture harboring these rascals as well as seats in theaters. In offices, reports abound of infested work cubicles, where clutter and file cabinets provide small spaces in which bed bugs can hide. Bed bugs likely arrive in businesses and schools as hitchhikers from infested homes, traveling on clothing, book bags, backpacks, or briefcases.
President Lincoln sees just how small bed bug eggs really are.
Several hypotheses explain the marked increase in reports of bedbugs in dwellings, schools, college dormitories, hotels, hospitals, and elder care facilities. Prior to the Second World War, bed bugs were commonplace in detached homes and multifamily dwellings in the US. The advent of insecticides such as DDT after the Second World War greatly reduced the incidence of bed bugs in this country and abroad. Indoor pests including cockroaches and ants were targets of liberal applications of potent residual insecticides. These practices also probably knocked down populations of bed bugs. A shift away from broadcast applications of DDT to targeted approaches using traps and baits for indoor pests may have opened the door for bed bugs to reappear as major pests. Moreover, one class of insecticides called synthetic pyrethroids became a mainstay for controlling indoor pests, including bed bugs. Recent studies revealed widespread resistance of bed bugs to some synthetic pyrethroids, rendering this class of insecticides far less effective in killing bed bugs than when these products first came into use.
Another piece of the bed bug puzzle lies with an increase in international travel to regions of the world were bed bugs are common. International travel provides opportunity for these clever stowaways to enter this country. Bed bugs readily hide in concealed places such as luggage, and due to their small size and cryptic habits they travel right along with globetrotters. We have not yet found a wall tiny enough to keep bed bugs out of our nation. A third factor identified with the uptick in bed bug infestations is the exchange of second hand furniture. Used sofas, bedding, chests of drawers, and other furniture provide great opportunity for bed bugs to move from one home to another.
Bed bugs, tiny vampires of the night, scatter when exposed to bright light or cling to each other in a roiling ball of bugs large and small.
There is some good news in this story. First, DC has done a good job in licking the bed bug in schools problem and students should soon be back to their regular classrooms. The second piece of good news is that bed bugs are not known to be carriers of human disease. However, following a bed bug bite, the human body reacts to proteins injected into the skin by the bug as it feeds. The reaction to the bite is highly variable and ranges from nothing to large itchy red welts. My reaction appears within a day but for others welts can appear weeks after an encounter. According to a study by Michael Potter and his colleagues at the University of Kentucky, for many people the reaction to the bite is minimal. Factors such as gender and ethnicity do not seem to affect the strength of one’s reaction to a bite. Age, however, apparently does. The elderly are less likely to react to bed bug bites than are younger folks. This is not good news because bed bug bites are often a harbinger of an incipient infestation. More importantly, these findings underscore the need for a high level of bed bug awareness and vigilance in facilities providing care and housing for seniors who may not know that they are being bitten.
Shed skins and dark spots of excrement on a sheet or a mattress are clues of a bed bug infestation.
How can you avoid bed bug infestations? When you travel be aware of your surroundings. If you stay in a hotel, inspect your bed. Look for the bugs or their telltale signs such as shed skins or dark excrement spots on the mattress, especially along the seam. Use a small flashlight to look on the bed frame and behind the headboard. To reduce the risk of little stowaways entering your luggage and coming home with you, elevate your suitcase and place it on a luggage stand, not the bed. Keep soiled and clean clothes in sealed plastic bags. Do not toss worn items on the floor. After returning home, vacuum out all luggage and toss your clothes into the dryer. By exposing clothing, bedding, backpacks, and other items to dry heat of 120°F or better for 20 to 30 minutes, all life stages of bed bugs will be killed. Portable heating boxes are available to heat items that might be damaged or are too large for dryer.
Avoid creating an infestation in your home with used furnishings. Beware of second hand furniture especially bedroom items. Be sure to inspect thoroughly any used mattresses, box springs, bed frames, nightstands, and mirrors. College students returning to campus should resist the urge to go dumpster diving for dorm-room or apartment furnishings! This is a good way to move infested furniture into your room. Experts recommend the use of bed bug-proof encasements for mattresses and box springs. Bed bugs love to hide in these places and encasements force them into the open where they are more easily detected. Small entrapment devices can also be place under the legs of beds or sofas. Bed bugs climb in but cannot climb out. This makes detection easier even when populations are low.
Skin rash where bed bugs fed on sensitive individual.
Unusual bites may be your first sign of an infestation. If you suspect an infestation, confirm that the cause of the bites are human bed bugs and not another arthropod or closely related bug associated with bats or birds that have entered your home. To do this you will need to capture one of these rascals and have it identified by an expert. Bat bugs and bird bugs are common and often mistaken for bed bugs. If bird or bat bugs invade, then the solution is to eliminate the nest (birds) and exclude birds and bats from the house with screening and repair of structures. If you confirm a bed bug infestation, you may not want to go it alone. A professional pest control operator will have the tools, techniques, and an integrated pest management (IPM) plan to detect and deal with the problem. Some commercial firms employ bed bug sniffing dogs to detect infestations. Unlike their handlers, these canines work for kibble. They are extraordinarily adept at finding bed bugs. Once an infestation is confirmed, the solution will involve more than one visit. Professionals may use a variety of management approaches involving treatments of heat or cold, the application of EPA registered insecticides, and a variety of other methods to exclude and thwart these bloodsuckers. Some things that you can do to help these professionals is to reduce clutter in the bedroom and around the home, vacuum floors and baseboards thoroughly and repeatedly, wash all bedclothes in hot water, and discard or encase infested mattresses and box springs.
Ridding a school, home, apartment, office, business, theater, hotel, health care facility, or any structure of bed bugs involves a serious ongoing commitment of time and resources by all parties involved – administrators, parents, renters, occupants, owners, property managers and pest management professionals. As bed bugs become more widespread and commonplace, early detection, rational discussion, and carefully designed and executed management programs will help us deal with these disagreeable characters.
References
Special thanks to my colleagues for providing bed bugs videotaped and photographed for this episode. Stimulating discussions with Reg Coler, Larry Pinto, and Rich Cooper who provided much of the insight for this story. The fascinating article s“[Bed Bugs] The Sensitivity Spectrum: Human Reactions to Bed Bug Bites” by Michael F. Potter, Kenneth F. Haynes, Kevin Connelly, Michael Deutsch, Erich Hardebeck, Don Partin, and Ron Harrison, and “Insecticide Resistance in the Bed Bug: A Factor in the Pest’s Sudden Resurgence?” by Alvaro Romero, Michael Potter, Daniel Potter, and Kenneth Haynes were used in references for this episode.
For more information on bed bugs, please visit the following web sites:
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef636.htm