Importance as pests Economic impact Bites and health effects

Public Health Significance of Urban Pests 139 1997. Some people can develop a general malaise from numerous bedbug bites; that, along with the loss of sleep and extreme itching of bug bites, can lower a person’s vitality and make individuals listless and almost constantly uncomfortable. Because of the media attention given to bedbugs in recent years, people may more rea- dily suspect bedbug bites as a most likely cause of a rash or skin irritation. Physicians commonly will not rule this out, as it is not possible to positively identify a skin irritation as a bedbug bite. It is common for those experienced with bedbugs to look at an irrita- tion and eliminate bedbugs as a possible cause; however, just examining an irritated area will not determine conclusively the source of the bite. Building inspectors that search for bedbugs should make sure that an infestation is confirmed via inspection prior to any action or, at least, determine that the victim is not suffering from delusory parasitosis, where he or she believes that they have been bitten by an invisible pest. Bedbug bites can be confused with numerous dermatological conditions, including those of psychological origin such as delusory parasitosis. If the person affected is complaining about bites, but an entomological source cannot be found, that person should seek medical attention.

4.3.4. Importance as pests

Because they are very small, nocturnal, seek cryptic harbourages, and can detect and avoid many chemicals including cleaning agents, common bedbugs are often hard to control. Complete elimination of an established bedbug population is nearly impossible to accom- plish in a single visit by most PMPs. They are easily transported on or in luggage, furni- ture, boxes, or even on clothes. They are very thin, except just after a blood-meal, and can fit through or hide in very narrow cracks. In the absence of hosts, adults can live without feeding for several months to more than a year and nymphs for three months or longer. This pest has substantially increased in importance as a result of the public’s fear of bedbugs, their characteristic odour and their feeding behaviour. Because bedbug fee- ding can cause serious physical distress mainly persistent, intense itching, which varies with each individual, demands for prompt, effective control are increasing significantly, too.

4.3.5. Economic impact

There are neither precise nor detailed records of the costs of bedbug control efforts nor of any of the related costs to people bitten in residential, commercial or institutional hou- sing. Costs for the hospitality industry include: • increased laundry expenses • replacement of bedding and furniture • structural cleaning and physical modifications • lost revenue from negative publicity • insurance claims and lawsuits. As an example of one of the simplest cases, a reasonable cost estimate for the inspection and effective treatment of a small infestation, involving a bed and two nearby floor–wall Bedbugs 138

4.3.3. Bites and health effects

Although their bite is often nearly undetectable, the saliva of bedbugs contains biologi- cally and enzymatically active proteins that may cause a progressive immunogenic and allergenic reaction to repeated biting. Depending on the combined biting intensity and frequency, there are typically five stages of symptoms, including no reaction, delayed reaction, delayed plus immediate reaction, immediate reaction only and, finally, no reac- tion. A common hypersensitivity response that follows bedbug bites is papular urticaria, a disorder manifested by chronic or recurrent papules. Rarely, a disseminated bullous eruption with systemic reaction may occur Liebold, Schliemann-Willers Wollina, 2003. Typical symptoms include a raised, inflamed, reddish wheal at each feeding site. Such wheals may itch very intensely for several successive days. Immediate immune reactions may appear from 1 to 24 hours after a given bite and may last 1–2 days, but delayed immune reactions usually first appear 1–3 days after a bite and may last 2–5 days Feingold, Benjamini Michaeli, 1968. In the cases of delayed reactions, it is often difficult to pinpoint the source, as the victim may have visited seve- ral different rooms in several locations over that period. Consequently, upon manifesta- tion of symptoms, the previous night’s lodging may be suspected; however, the bites may have occurred several nights prior. People bitten frequently by these bugs may develop a so-called sensitivity syndrome, which may include nervousness, nearly constant agitation jumpiness, and sleeplessness. In such cases, either removing the bedbugs either physi- cally or by the use of an insecticide or relocating the person has caused the syndrome to disappear over time. Several different species of Cimicidae may bite people, including tropical bedbugs, some bat bugs and some swallow bugs, as mentioned previously in sec- tion 4.2 Ryckman Bentley, 1979. Also, a social stigma may be associated with having an infestation of bedbugs Usinger, 1966; Krinsky, 2002. Currently, there is no requirement to report bedbug infestations to any public health or other government agency at any level. Medical clinicians, however, have reported the fol- lowing significant symptoms as due to common bedbug bites: • serious local redness and intense itching, both immediately and after several days delay Sansom, Reynolds Peachey, 1992; • disseminated bullous eruption with systemic reaction Liebold, Schliemann-Willers Wollina, 2003; and • true anaphylaxis, which has been misinterpreted as coronary occlusion Parsons, 1955. Besides the effects of direct bites, airborne common bedbug allergens that are always released during infestations may produce bronchial asthma. Within a group of 54 asth- matic Egyptian patients, 37.1 reacted positively to a common bedbug head and thorax extract, and 50.1 reacted positively to an abdominal common bedbug extract Abou Gamra et al., 1991. Numerous routine bedbug bites can contribute to anaemia and may even make a person more susceptible to common diseases Usinger, 1966; Snetsinger, Public Health Significance of Urban Pests 141 much more common in poorer communities, these practices probably help to rapidly and repeatedly spread bedbugs to new sites and to redistribute them to places from which they may have been eliminated earlier. Large multi-unit buildings common to poor areas can be very hard to rid of bedbugs. Once bedbugs become established, any control effort that does not include checking the whole building at nearly the same time, along with a coordinated occupant education and treatment effort as needed, will usually fail, because the bugs will frequently move away from any partially treated and potentially repellent active sites into adjacent rooms. Their movements are generally unencumbered, because they readily move through wall voids and along utility lines, heating ducts, elevator shafts, and laundry and mail chutes.

4.5. An integrated approach to bedbug management