Why Is the Control of Bed Bugs' (Cimex spp.) Infestations as an Urban Environmental Health Pest Difficult? Reasons & Control Strategies

Bed bug infestation is a neglected and unreported health and medical concern in comparison with other vector-borne diseases such as Leishmaniosis, Malaria, and Crimean-Congo hemorrhagic fever, which is increasing worldwide 2 . Bed bugs infestation can produce psychological distress with nightmares, insomnia, anxiety, avoidance behaviors, anemia, and personal dysfunction. So far, bed bugs have not been able to vector human pathogens. Their bites are painless and cause itching skin in individuals, but different complications can arise in individuals. Bed bug bites are mainly on the arms, forearms, legs, neck, and face 5, 6, 2 . Bed bugs are a severe public health issues with difficult and costly eradication methods. They are ordinarily nocturnal and hide in protected places 7


Bed bug resistant
In general, bed bugs' resistant to DDT has been determined since 1960s.The first case of bed bugs resistance to DDT was reported and confirmed in 1947s in Hawaii.Researchers reported bed bugs' resistant to other groups of insecticides such as organophosphates, carbamates, and pyrethroids all over the world 10,22,23 .Bed bugs' populations can become resistant by biochemical resistance 24 , molecular resistance 22 and cuticular resistance 25

Lack of identification, knowledge, and awareness against bed bug
The general lack of public awareness about bed bug is one of the most important factors that increased its infestation.In addition, people are usually not aware about the existence of bed bugs.So, at the time of infestation, bed bugs are often quickly picked by other individuals and transported into other houses 26 .Despite the increasing incidence of infestation, relatively few people can identify a bed bug.Hence, public awareness and knowledge are the key factors to reduce the bed bug infestation 2, 27 .

Poor bed bug management practices
Implementation of controlling programs using just one strategy is rarely efficient and only causes immediate effects in eliminating the bed bugs' infestation.Most of the residents of houses, apartments, hotels, dormitories, and other human dwellings have no effective technical knowledge to prevent and control the bed bug infestation 28 .

Integrated pest management (IPM) methods to control bed bug
Recently, IPM method has been applied as the main tool to control bed bug.Research carried out in the recent eight years showed that IPM was the best approach to eliminate bed bug infestation in contaminated houses 9,28 .It refers to a logical combination of physical, environmental, mechanical, biological, and chemical controlling methods to minimize the risk of exposure to chemical insecticides and control the pests.According to the definition, IPM is a promising and safe strategy for humans and the environment and includes active surveillance and simultaneous use of both chemical and non-chemical control strategies, implementation of follow-ups and preventive measures 29 .
In order to control bed bugs, IPM strategy includes survey for infestation, identification of its severity, cleaning all contaminated areas in order to eliminate the bed bug habitats (sanitation), physical removal (mechanical) of bed bugs, effective and careful use of insecticides according to the instructions, following the inspections daily, weekly, and monthly 29,30 .
Based on the latest research on the control of bed bugs by Wang et al., IPM programs were more effective in reducing and exterminating the bed bugs' infestations than the traditional pest control services 31 .The findings of Wang et al. demonstrated two methods of pest control: (a) Non-chemical tools including steam, vacuuming, mattress encasement, de-cluttering, discarding severely infested items, and frequent laundering as well as (b) Chemical methods including insecticide sprays and dusts, which are named as IPM approach 31 .They indicated that these two methods were necessary for eliminating bed bug infestations rapidly from human's dwellings (Figure 1) 31 .
. The findings of Doggett et al. demonstrated that cuticle thickness is present within a pyrethroidresistant strain of C. lectularius 22 .Moreover, Moussian et al. demonstrated that the bed bug (C.lectularius) cuticle acted as a protective coat against the penetration of insecticides 25 .