Resistance to pesticides has increased significantly in recent decades. The carbamate insecticide propoxur is highly toxic to bed bugs, but it has potential toxicity to children exposed to it, and the US Environmental Protection Agency has been reluctant to approve it for indoor use. Boric acid, occasionally applied as a safe indoor insecticide, is not effective against bed bugs because they do not groom. Epidemiology
Bed bugs occur around the world. Before the 1950s about 30% of houses in the United States had bedbugs. This percentage has since fallen, which is believed to be partly due to the use of DDT to kill cockroaches. The invention of the vacuum cleaner and simplification of furniture design may have also played a role in the decrease. Others believe it might simply be the cyclical nature of the organism.However, rates of infestation in developed countries have increased dramatically since the 1980s. This is thought to be due to greater foreign travel, increased immigration from the developing world to the developed world, more frequent exchange of second-hand furnishings among homes, a greater focus on control of other pests, resulting in neglect of bed bug countermeasures, and increasing bedbug resistance to pesticides. Lower cockroach populations due to insecticide use may have aided bed bugs resurgence, since cockroaches are known to sometimes predate them.
Detection
Bed bugs can exist singly but tend to congregate once established. Although strictly parasitic, they spend only a tiny fraction of their lives physically attached to hosts. Once a bed bug finishes feeding, it follows a chemical trail to return to a nearby harborage, commonly in or near beds or couches, where they live in clusters of adults, juveniles, and eggs. These places may include luggage, vehicles interiors, furniture, bedside clutter—even inside electrical sockets or laptop computers. Bed bugs may also lodge 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 C. 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 between 11% and 83%.Homemade detectors have been developed. Bedbug detectors, often referred to as "monitors" or "traps", use attractant based methods such as lactic acid or carbon dioxide (associated with the presence of a human body) or pheromones to trap bugs in a container. Bedbug detectors can confirm a bedbug infestation but they are not effective for eradication. Differential diagnosis
Other possible conditions with which these conditions can be confused include scabies, gamasoidosis, allergic reactions, mosquito bites, spider bites, chicken pox and bacterial skin infections.