Inspection Detection Inspection, detection and education

Public Health Significance of Urban Pests 143 indication of a developing infestation.

4.5.2.3. Education

Educating dwelling occupants affected by bedbug infestations is essential to ensure that they actively and voluntarily cooperate in any control programme or effort needed. These occupants are usually the ones who must improve and maintain sanitation, reduce and minimize clutter, and perhaps seal harbourages, to exclude or restrict the movements of the bug population. It can be helpful if dwelling occupants affected by bedbug infes- tations understand as fully as possible the bugs – their biology and behaviour – and the strategies and techniques proposed or being used to control them. To foster such unders- tanding, educational efforts may include verbal explanations, answering questions, infor- mation posted on an Internet web site, or at least a concise printed handout in a language that people can read and understand. Good communications with homeowners, housing managers and any relevant government agencies should be maintained throughout a bed- bug control programme.

4.5.3. Physical removal and exclusion

A number of possibilities exist for physically removing or excluding bedbugs.

4.5.3.1. Physical removal

Bedbugs can be physically removed from exposed harbourages or resting sites, such as edges of a box spring or mattress seams, by sucking them up with a vacuum cleaner. Using a HEPA-filtered vacuum, which removes more than 99 of all particles greater than 0.3µm in diameter, would ensure that allergens associated with bedbugs or their debris were being removed concurrently. Vacuuming will usually kill a large portion of those bugs and can be done at the same time as an inspection, eliminating immediately a significant portion of the pest population. Bedbugs might also be lifted from exposed res- ting sites with commercially available tape or by hand, or just brushed off directly into a container of rubbing alcohol or soapy water Potter, 2004; Gooch, 2005.

4.5.3.2. Exclusion

Sealing access to harbourages can effectively isolate bedbug populations. Bedbugs have specially adapted piercing–sucking mouthparts, and three-segmented, structurally pri- mitive tarsi the terminal segments of the leg with claws. That makes them incapable of chewing or clawing through even a very thin layer of sealant or an unbroken layer of paper or cloth. Sealing a layer of almost any material in place, so that it completely covers the opening of any harbourage, can stop bedbugs from passing through. If any bedbug is thus effectively sealed inside a void or harbourage, it could be permanently removed from the pest population. Even if such a bedbug were to live for another year, or two years or longer, it must die there if that space is never unsealed while the bug is still alive. Just sealing most of the known openings between a harbourage and the bugs’ usual host access sites will restrict the bugs’ movements and help temporarily reduce the inten- sity of their feeding. Enclosing clothes and other items in plastic bags and similarly tigh- Bedbugs 142

4.5.2. Inspection, detection and education

4.5.2.1. Inspection

Detailed inspection by a qualified person is the most essential basic element at the start of any effective effort to control bedbugs. The bugs must be detected promptly, correctly identified and at least a rough estimate of the extent of harbourage sites must be determined as rapidly as possible. No currently known device or technique is available to effectively attract or trap bedbugs, so a tho- rough visual inspection must be done. Certain pyrethrin- based flushing agents can be used to help stimulate the bugs to move around and make them much easier to detect in limited populations. Once detected, correct identification of the pest bugs is important, to focus fur- ther inspections and facilitate the application of control techniques or products that are precise and limited in scope – for example, for treatment of cimicid bugs that feed mainly on certain species of bats or birds.

4.5.2.2. Detection

Typical actions and signs that can accurately detect a bedbug infestation include: • seeing or collecting live bugs Fig 4.4; • smelling the characteristic odour, finding their eggs or so-called cast skins in harbou- rages or near feeding sites; • finding dark faecal deposits or lighter rust-like spots on bed linens or in tradi- tional harbourages Fig. 4.5; and • noting and recording where and when bite victims know or think they were bitten. The use of both sticky traps and insectici- dal aerosols that flush out or excite the bugs can potentially augment monitoring. Any combination of two or more of these signs can help verify the infestation and determine the distribution and prevalence of the bugs. For species that feed mainly on bats or birds, detecting and locating the nests of their local hosts is important. The presence of typical hosts may be an early Fig. 4.5. Bedbug staining is typical of a dropped par- tially digested blood-meal Source: Photo by H. Harlan. Fig. 4.4. Bedbug found on a mattress dust cover Source: Photo by G. Baumann. Public Health Significance of Urban Pests 145

4.5.4.4. Steam