Although no one can be completely sure of the reasons for the bed bug resurgence, experts have several theories.
The most likely cause for the bed bug resurgence seems to be the increase in international travel to countries where bed bugs are commonplace. In some areas of the world, bed bugs were never eradicated.
Another issue is that may be contributing to the increase in bed bug infestations is that the pesticides we have at our disposal today are not nearly as effective or long lasting than those we had in the 1950s through the 1970s. DDT and similar pesticides were banned because of serious hazards to wildlife, the environment and human health.
There are only a few pesticides approved for indoor use by the EPA and even fewer approved for use on bed bugs. In addition, studies have shown that bed bugs are developing resistance to the most commonly used pyrethroid based insecticides.
Methods of pesticide applications have been modified to reduce human exposure which may be contributing to the increase in bed bugs. Baits (which are not effective against bed bugs) are now being used to treat ants and cockroaches, replacing broadcast spraying of insecticides.
Americans are not educated about bed bugs and may unknowingly engage in behaviors that put them at high risk for getting bed bugs. For example, purchasing used furniture or electronics without checking to see if they have bed bugs or by failing to take precautions when traveling.
Also, because of this lack of awareness, people may overlook the signs of early infestation. This allows the bed bug infestation to spread widely through the residence and for the occupants to transfer bed bugs to other locations before they become aware of the problem.