Bed Bugs

Bed Bugs are a type of insect in the Order Hemiptera (Hemi = half, pteron = wing), Family Cimicidae. Bed bugs are a type of external parasite of mammals and avians. The important species that bites and sucks human blood is Cimex Hemipterus which is found in hot countries. In Thailand, there has been no reports of bed bug pandemic for several years so the younger generations nowadays do not know what bed bugs are. However, in the last 2-3 years, there has been news of bed bugs. There was a spread of bed bugs that bothered train passengers causing the State Railway of Thailand to suspend its operation to eradicate bed bugs in passenger trains. More bed bugs have also been found in hotels. This is because foreign tourists bringing bed bugs with them resulting in an epidemic of bed bugs in hotels and accommodations in main tourist cities of Thailand for example Bangkok, Chonburi, Chiang Mai, Phuket and Krabi. Entrepreneurs of hotel and accommodation businesses have been badly affected by the issue of the spread of bed bugs in their accommodation. Clean places may also be the habitats and breeding grounds of bed bugs even though there are only a few bed bugs that cannot be totally eradicated.

At the end of the 20th century, the population of bed bugs reduced very quickly due to the use of DDT (Dichloro-diphenyltricholoethane). However, at the start of the century, it has been found that bed bugs have spread very quickly and have become a problem worldwide. At present, there are reports of bed bugs in several continents such as North America, South America, Europe, Australia and Asia. There have also been reports of resistance against pesticides that are used to kill bed bugs especially pyrethroid pesticides. The resistance against pesticides of bed bugs has also emerged in Thailand. The study of health science research institute, department of medical sciences, has been found that bed bugs found in hotels in Bangkok, Chon Buri, Chiang Mai, Phuket and Krabi have shown resistance against several types of pesticides. Hence bed bugs have become difficult to control. If this issue is not corrected, physical and mental health may be disturbed. It may also cause a long-term problem to tourism and hotel businesses.

Medical and Public Health Significance

Bed bugs are a type of insects that are of medical significance. This is because bed bugs cause people and animals to be annoyed by they sucking blood. The person who has been bitten will feel itchy from bed bug bite because of the allergy to the saliva of a bed bug. Later, the itchiness may change into swelling, allergy and infectious skin in that area. In 2011, a Canadian scientist has discovered that bed bugs are important carriers of 2 types of bacteria that resist antibiotics. Moreover, there have been lab tests which have found that certain important protozoa such as Leishmania donovani and L. tropica and Hepatitis B can grow inside bed bugs. However, there is no concrete evidence that bed bugs are carriers of protozoa and such viruses to humans in the natural condition. In avians, bed bugs may cause anaemia in chicken, turkeys and pigeons.

Biological and Ecological Information

Bed bugs have incomplete metamorphosis which includes egg phase, nymph phase and adult phase. An adult bed bug looks similar to a nymph but is bigger. Female bed bugs lay 1-5 eggs a day however, this can increase to 12 eggs a day. Over the course of its life, a female bed bug is able to lay as many as 500 eggs. The places where bed bugs like to lay eggs include headboard, under headboard, bed edges, wooden frame under the bed, box spring, wooden cornice of headboard and wooden cornice around the rooms, on the bed, on the bed edges, under the bed, side table for telephone and lamp, areas of a carpet near a wall, dressing table, wooden tissue box, bag rest, wardrobe, rattan chair, curtain, room wall, pillar edges, window edges,

picture frame, a hole or crack on the wall and electrical plugs. Eggs of bed bugs are white. Each is about 1-1.5 millimetres long. It has a lid and cement-like substance around it allowing an egg to be attached to the place where it is laid. There are 5 stages of nymph (stage 1- stage 5). In each stage, a nymph needs to consume blood at least once before progressing to the next stage. However, a nymph of a bed bug is able to live for 3-4 months without blood. It takes approximately 6-8 weeks for an egg to grow into an adult. However, the rate of growth depends on food and temperature under appropriate conditions.

Life Cycle of a Bed Bug
Photo courtesy: MidMos Solutions Ltd.

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An adult bed bug has a body which is flat and of an oval shape. It is approximatley 5-6 millimetres long. It has the colour of light to dark brown. Its head is short. There are 4 sections in each of its antennae. A bed bug’s mouth is piercing sucking divided into 3 sections that can be stored in a nook under the body. The front of its thorax is indented. The sides expand out wider than other sections. Its wings which come in the form of wing pads are not developed. There are 6 legs. Its abdomen is of an egg shape. One can see its sections clearly. Male bed bugs have aedeagus (sexual organ) which is narrow and pointy at the end of its body. Female has an opening of spermalege or organ of Berlese at the fifth abdomen section for the benefit of breeding. An adult bed bug has one pair of scent gland in the lower part of the thorax. In the nymph stage, a similar gland has been found in the upper part of the thorax. A similar type of gland has been found in the upper part of the abdomen. Such glands help making bed bugs having unique scents which are hexanol and octenol. Bed bugs release these scents from the body to protect themselves. An adult bed bug may live for 6 -12 months. They are able to continue hiding and not eating blood from several months to one year. Normally bed bugs come out to suck human blood at night as well as in dark places for instance when one turns off the lights to prepare for bed or in cinemas. Nonetheless, bed bugs may suck human blood during the day should they want some blood. During the day, bed bugs hide themselves and live along the edges of bed, nooks of bed, nooks of chairs, along the cracks on the floor, wall and cracks in buildings. Bed bugs are found in various public places such as hotels, cinemas, schools, trains and buses especially dirty and crowded places such as prisons, refugee camps and military camps. Bed bugs may come out of their hidings for as far as 6 metres to suck human blood before going back or finding a new place to hide/live.

Visual comparison of adult bedbug both sexes.

 

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Females
bed-bug-4
Male

 

Prevention and Eradication of Bed Bugs

Efficient prevention and eradication of bed bugs need to combine various methods together for instance providing information about bed bugs, surveys and evaluations before and after the control, control using appropriate physical methods, management of the environment of places that bed bugs are found, appropriate use of pesticides to eradicate bed bugs as well as the test to find the resistance against pesticides used.

Survey of Bed Bugs

Tools and equipment needed for the survey of bed bugs include torches, tweezers, paintbrush, and small pointy iron (to move bed bugs that are in small nooks), plastic bottle with a screw lid to store bed bugs, magnifying glass and a result form. Bed bugs are to be carefully and regularly surveyed. This is to be done at least once a month. Places in the bed room that bed bugs are found include bed headboard, decorations at the bed headboard, bed edges, wooden frame under the bed, box spring, wooden cornice of headboard and wooden cornice around the rooms, on the bed, on the bed edges, under the bed, side table for telephone and lamp, areas of a carpet near a wall, dressing table, wooden tissue box, bag rest, wardrobe, rattan chair, curtain, room wall, pillar edges, window edges and picture frame. Surveys of bed bugs are to be done both before and after the control process.

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Panel ornamental headboards
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Fabric panels ornamental headboards
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Turndown below
bed-bug-9
on the Couch

 

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Bedbug mattress seams area
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Roy Black of bedbug feces.
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Treatment of bedbug peel left.
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Bedbug eggs

 

Indicators of Bed Bugs in an area

  • Bed bugs (alive or dead)
  • Black fece stains of bed bugs
  • Remainders from the molting process of bed bugs
  • Eggs of bed bugs (which may have already hatched or not) (bed bugs along the bed seams and eggs of bed bugs).

Non-chemical prevention and eradication of Bed Bugs

1. 1. Physical Bed Bug Eradication

Vacuum cleaner using a vacuum cleaner to clean carpets and floors may be able to kill some bed bugs that are found outside their hiding places. However, it is not able to kill eggs or bed bugs that are hidden within their hiding spaces. One should kill bed bugs in the dust bag inside the vacuum cleaner right after the operation. Otherwise bed bugs may spread to other rooms. One is able to eradicate bed bugs in the dust bag through the following procedure;

  • Immerse a dust bag in a container that has water and a high concentration of detergent (the dust bag needs to be fully immersed) for at least 1 hour.
  • Boil the dust bag in boiling water for at least 10 minutes.
  • Dry the dust bag in a dryer with the temperature at least 60° C for at least 30 minutes.

Heat one may use heat to eradicate bed bugs;

  • Boil bedsheets, curtain as well as fabric beddings and other objects that have been taken from a room where bed bugs are found in water that has the temperature of at least 60ºC for at least 10 minutes to eradicate both bed bugs and eggs that may still be in such fabrics.
  • Dry clean bed sheets as well as fabric beddings and other objects or dry fabrics with a dryer at the temperature of at least 60ºC for at least 30 minutes. This is able to eradicate bed bugs at all stages including the egg stage.
  • Use a steamer to spray on bed bugs at the spot where they are found. Bed bugs are killed when they face steams at the temperature of at least 60ºC (steams coming out of the end of the tube at the distance of less than 2.5 centimetres). However, one needs to be careful with regards to the humidity of residue steam on fabric materials. Such issue may result in bacteria or moulds. Hence, after being spreayed by hot water, fabric materials should be hot blown to ensure that they are completely dry.
  • Use a heater to heat up the room for the room to have the internal temperature of 50ºC for at least 3 hours or at the temperature of 60ºC for 1 hour. This will eradicate bed bugs as well as their eggs. This is the approach that completely eradicate all bed bugs in a room.

2. Environmental Adjustment of the Areas where Bed Bugs are found

One is to improve one’s room by destroying all the hiding areas of bed bugs for instance tears of wallpapers, areas between the headboard and a wall, areas between the wooden cornice and a wall and using silicone to renovate or rubber cement to seal these cracks to prevent them from being used as hiding spaces for bed bugs.

Chemical Prevention and Eradication of Bed Bugs

In terms of chemical prevention and eradication of bed bugs, pesticides need to be sprayed. The pesticides used must be the types that the bed bugs have not resisted to. Such chemical needs to be sprayed thoroughly to all nooks and spaces that may be hiding spaces of bed bugs. One is to survey and evaluate approximately 3-7 days after the control action namely the spraying of chemical to kill bed bugs. The survey needs to be thorough. If bed bugs are still found, that will mean the spraying has not covered the areas where there are bed bugs and spraying of chemical will need to be repeated. The evaluation has to go on until no bed bugs are found. Moreover, one is to change groups of pesticides used every 6-12 months to reduce the issue of chemical resistance of bed bugs. World Health Organisation has recommended pesticides that are to be used to control bed bugs as shown in the following table;

Insecticide Insecticide groupa WHO hazard
classificationb
Concentration
(g/l or g/kg)
Bendiocarb C ll 2.4
Flufenoxuron IGR U 0.3
Methoprene IGR U 0.9
Chlorpyrifos OP ll 2-5
Malathion OP lll 20
Pirimiphos-methyl OP lll 10
α-Cypermethrin P ll 0.3-0.6
β-Cyfluthrin P ll 0.25-0.5
Bifenthrin P ll 0.48-0.96
Cyfluthrin P ll 0.4
Cypermethrin P ll 0.5-2.0
Cyphenothrin P ll 0.5-1.0
Deltamethrin P ll 0.3 (0.5c)
λ-Cyhalothrin P ll 0.03
Permethrin P ll 1.25
d-Phenothrin P U 1.0-2.0
Resemethrin P lll 3
Tetramethrin P U 1-2

 

Using Liquid Spray Pesticides

National Institute of Health of Thailand, Department of Medical Sciences has studied the effectiveness of 10 types of pesticides (Liquid Spray) with active substances from 6 chemical groups that are used to eradicate/kill insects namely; Organophosphate (Diazinon); Carbamate (Fenobucarb, Propoxur); Pyrethroid (Esfenvalerate, Cypermethirn, Bifentrin, Etofenprox); Pyrrole (Chlorfenapyr); Phenylpyrazole (Fipronil); and Neonicotinoid (Imidacloprid). These are popular among the pest control entrepreneurs for controlling crawling insects (such as cockroaches, ants, termites and bed bugs). Sample colonies are taken from various provinces. Each type of pesticide chemicals is diluted by water to reach concentration levels indicated on the labels. Then they are sprayed directly onto bed bugs. From the study, it has been found that Imidacloprid is the most effective pesticide chemical followed by Chlorfenapyr and Fipronil.

Table showing effectiveness of pesticide products (liquid spray) in eradicating bed bugs whose colonies are taken from various provinces in Thailand

Chemical insecticide The active ingredient Concentration used (mg/L) LT50 (day) of bedbugs from different provinces
Bangkok Chon Buri Phuket Krabi Chiang Mai
A Diazinon 4,600 34.2 8.0 8.4 7.7 18.3
B Fenobucarb 5,000 42.8 11.6 6.0 10.0 8.8
C Propoxur 250 72.4 7.1 9.4 30.3 NA*
D Esfenvalerate 500 54.9 7.7 9.7 8.9 19.9
E Cypermethrin 1,000 NA* 6.4 7.1 9.7 7.7
F Bifenthrin 1,000 36.6 7.5 23.2 NA* NA*
G Etofenprox 4,000 37.7 8.0 11.2 10.1 10.1
H Chlorfenapyr 624 8.7 3.7 3.3 1.5 3.8
I Fipronil 250 12.7 1.3 6.2 0.8 9.5
J Imidacloprid 500 0.4 0.8 0.03 0.4 0.9

Remarks:

1) LT50 s the time period (days) that bed bugs are exposed to pesticides and half (50%) of the tested bed bugs die as a result.
2) NA* refers to the condition that none of bed bugs are killed over the testing period.

It is worth noting that the three types of pesticides namely Imidacloprid, Chlorfenapyr and Fipronil are new groups of pesticides that have never been used to eradicate bed bugs before (pesticides that WHO recommends to use with bed bugs). For the other 7 types of pesticides, it has been found that they have low effectiveness in killing bed bugs. This coincides with the data received from the survey of large companies that use pesticides (liquid spray) especially pesticides in the groups of Organophosphate and Carbarnate which are used to eradicate insects in hotel rooms such as cockroaches, ants, termites as well as bed bugs.

Pesticide Spraying Procedures

1. One should mix pesticide chemicals by following suggestions indicated in the product labels.
2. While mixing pesticide, one should wear protective gloves and masks to avoid being exposed to the chemials. While spraying, one should stand upwind. Do not let chemicals enter your eyes, nose, mouth or on your skin.
3. Once the spraying of pesticide is finished, one needs to wash hands, face, body and hair thoroughly. Then change clothes before drinking or eating.
4. Do not throw empty containers of pesticide into rivers, canals and public water sources.
5. One should wash empty containers with water at least 3 times before destroying or burying in the ground. One must not burn it with fire.

The use of Pesticides in the form of Aerosol

From the study of effectiveness of 8 types of aerosol pesticides that contain active substances in Pyrethroid group that are used to eradicate bed bugs, it has been found that most products have different effectiveness in eradicating bed bugs whose colonies are taken from provinces. It may be explained that this is caused by differing recipes and reacting substances of those products. Hence, mixing several reacting substances together are the way that can increase the effectiveness of pesticides even though the total amount of reacting substances is not very high. Moreover, the recipe types are one important factor that has an impact on the effectiveness of insect control. Normally, oil-based products are more effective compared to water-based products even though they both contain the same reacting substances and concentration level. This is because oil-based solution allows better attachment of reacting substances to insect bodies facilitating better absorption into their bodies when compared to water-based solution. The study on residue effects from additional experiments of the researchers has found that some surfaces such as filter papers and fabrics that have been sprayed by the said products until wet, once they are dry, they will not have any effectiveness in killing bed bugs. Hence, those who are to use these pesticides (aerosol) to kill bed bugs, need to keep in mind that these products will be effective only when they are sprayed directly onto the bed bugs. They have no residue effect. Hence they cannot be used to control bed bugs in their hiding places.

The Use of Fumigation Pest Control

The use of fumigation pest control has started to become more popular in controlling household insects especially abroad. It has been found that Vikane Gas which contains Sulfuryl Fluoride as reacting substance has been used to eradicate bed bugs in residential areas such as houses and hotels. This method is able to kill bed bugs of all phases from egg, nymph and adult phases without any residue toxin. In Thailand, it has been found that many pest control companies have recommended hotels to eradicate bed bugs with fumigation. The reacting substances are tablet phosphine (including Aluminium phosphide or Magnesium phosphide) and Methyl Bromide. These chemicals are normally used to kill pests that damage agricultural crops in barns or kill insects that may be hiding in packaged products in containers. However, the three fumigation methods of killing bed bugs have a setback. They are highly hazardous to human beings and pets that may cause immediate death if the operators cannot close all the leakages in the room properly allowing gas to leak outside. Hence, the operating company of fumigation needs to have experts who have been properly trained to ensure that the method is safe for human beings, animals and the environment. Another setback of fumigation is that it costs a lot (this depends on the conditions of the operating areas).

Thermal fogging using various types of pesticides, be it those in Pyrethroid or Organophosphate groups as well as the use of smoke pesticides (can) has been found not able to kill bed bugs in rooms.

Speed and Resistance Tests of bed bugs against Pesticides

According to the results of the study of Health Science Research Institute, Department of Medical Sciences (2009-2010), bed bugs that have been taken sample from 5 provinces namely Bangkok, Chiang Mai, Phuket, Krabi and Chonburi have built resistance against several groups of pesticide used in the test. Such groups include; Organochlorine (DDT, Dieldrin); Organophosphate (Malathion, Fenitrothion); Carbamate (Bendiocarb, Propoxur); and Pyrethroid (Cyfluthrin, Deltamethrin, Permethrin, Lambdacyhalothrin, Etofenprox). Hence, one should test the resistance against bed bug pesticides before and after the control operations every 6-12 months (should bed bugs are still found). One may consult and receive services of speed and resistance tests of bed bugs against pesticides at Health Science Research Institute, Department of Medical Sciences.

Summary of Procedures of Bed-bug Prevention and Eradication in Hotels

1. Train hotel personnel especially cleaners to have biological and ecological knowledge regarding bed bugs. They also need to know the methods of survey, prevention and eradication of bed bugs.

2. Cleaners are likely to be the first people to know that there are bed bugs in rooms. Hence, they should survey traces of bed bugs in hotel rooms carefully and thoroughly when they go in to clean. They need to observe certain indicators that there are bed bugs in the area. Such indicators include bodies of bed bugs (alive or dead); black fece stains; their eggs; and remainders from the molting process of bed bugs.

3. Should any of the above indicators is found, one needs to conduct a thorough survey of bed bugs in hotel rooms covering every inch of the room to find the hiding places of bed bugs for instance headboard, bedsheets, bed seams, night table, lamps, luggage rest, wardrobes, wallpaper, curtain, chairs, sofa etc. One should also dismantle decorations on the headboard and mattress base.

4. If bed bugs are found in one room, one should also survey the adjacent rooms both on the left and right as well as the opposite room(s).

5. One should conduct bed-bug eradication process using the methods appropriate to the place where bed-bugs are found using the combination of chemical and non-chemical approaches.

6. Bed-bug eradication without the use of chemicals may be done physically for instance, boiling and heating methods.

7. Chemical bed-bug eradication may be done using pesticides that have been known through researches that bed bugs have not resisted to. They may be used in the forms of liquid spray or aerosol. The spray needs to cover the whole area that has been found to be the hiding places of bed bugs. Partial spray may cause the control to be ineffective because bed bugs may move and escape quickly to other areas in the room as well as the adjacent rooms.

8. After spraying pesticides, one should not enter the room until the chemicals are completely dry (at least 48 hours) and the control evaluation needs to be done within the period of 3-7 days. However, if it has been found that there are bed bugs that are still alive (which may be caused by spraying in a non-comprehensive manner). One needs to repeat the spray follow by evaluations 3-7 days afterwards. Then the method needs to be repeated until no bed bugs are found. One must always note that it may not be possible to totally eradicate bed bugs in the first spray of pesticides. The process may need to be repeated 2-3 times for them to be totally eradicated.

9. Rooms are to be improved by dismantling and damaging all hiding places of bed bugs for instance, under-bed, tears of wallpapers, areas between the headboard and a wall, areas between the wooden cornice and a wall. Rooms are to be renovated using silicone or rubber cement to seal such cracks to prevent them from being used as hiding spaces for bed bugs.

10. Create log books of bed bugs found for ever room with details of the control and evaluation processes.

11. A Monitoring and Control of Bed Bugs in the Hotel Plan needs to be made. This should include the thorough and regular surveys of bed bugs in the room. The survey needs to be done at least once a month. Then the details need to be jotted down in log books even though no bed bugs are found. One must always keep in mind that even though bed bugs throughout the hotel have been eradicated, there is still a possibility that there may be new bed bugs coming with the guests who stay at the hotel.

12. Even though one bed bug or one of the indicators is found, one needs to immediately follow the procedure listed above.

13. One needs to specify the procedure when a customer complains of being bitten by insect especially bed bugs for instance, when moving a customer out of a hotel room in which bed bugs have been found, one will need to eradicate bed bugs in that room and the new room that the customer is moving to immediately when the customer has left. This is because bed bugs from the old room may spread to the new room as well as its adjacent rooms with the customer. Moreover, one needs to survey and evaluate the control carefully and thoroughly until bed bugs in that room are totally eradicated.

14. The image of a hotel in which bed bugs are found for ordinary people is dirtiness. Even though the hotel has tried to keep everything clean, a few bed bugs in the hotel without a quick response measures will result in the issue being expanded. It will become difficult to overcome and it may cause damage to the business in the long term.

Reference:

Bed Bugs: Biology and Measures of Prevention and Eradication, A Manual to Prevent and Eradicate Bed Bugs in Hotels and Residences by Department of Medical Sciences, Ministry of Public Health and the National Research Council of Thailand

***From the Manual for Personnel responsible for the use of hazardous materials at work, The Food and Drug Administration, Ministry of Public Health

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