Bedbugs are blood-sucking insects which feed from humans. They often live in bedding, beds and in cracks and crevices of surrounding walls and furniture. They may cause skin reactions and psychological effects, but are not known to transmit disease.
Over the past decade or two, bedbugs have made a dramatic comeback and are increasingly common in homes, apartments, hotels, healthcare facilities and schools. Immigration and international travel have contributed to the resurgence of bedbugs. In addition, changes in modern pest control practice, less effective insecticides and a decrease in societal vigilance have all contributed to this recurrence.
- The two main species of bedbugs are Cimex lectularius and Cimex hemipterus. Cimex lectularius are found in temperate areas. Cimex hemipterus are found in tropical zones.
- Bedbugs are brownish, wingless, flattened insects, measuring around 2-5 mm in length.
- They feed solely on the blood of animals. In addition to humans, they will also bite other warm-blooded animals (eg, dogs, cats and rodents).
They can actually survive for up to one year without eating. The ability to survive without a blood meal is longer at cooler temperatures. The adults can live for up to 18 months. They breed by laying eggs which hatch after around 10-20 days and take between 9-18 weeks to become adults. Females can lay around 300 eggs in their lifetime.
They are sometimes mistaken for ticks, cockroaches or carpet beetles. The immature bedbugs (nymphs) look much like the adults, other than being smaller and a lighter brown.
Bedbugs can crawl rapidly over floors, walls, ceilings and other surfaces. They cannot jump or fly. Bedbugs are inactive during the day, often hiding in dark places (eg, mattresses, bed frames, within plug sockets, in clothing or soft furnishings, in cracks and crevices of wooden furniture).
They live in both clean and dirty environments.
As bedbugs feed at night and inject an anaesthetic when they bite, the initial bite is usually not felt and most patients have no reaction to them. The biting process takes up to ten minutes but the person being bitten is usually unaware of it. The symptoms following being bitten by bedbugs vary but include:
- Little or no reaction. This is the case for most affected individuals.
- Three to four bites forming a line or a curve on the body (usually areas exposed during sleeping such as face, neck, arms) are very suggestive of bedbug bites.
- Isolated pruritus, papules or nodules can occur. Skin reactions most often start out as small macular lesions that can develop into wheals of around 5 cm in diameter. These are often intensely itchy.
- Occasionally, bullous eruptions may occur.
- Rarely, systemic reactions occur (eg, urticaria or even anaphylaxis).
- The onset of symptoms may be delayed, due to delayed allergic reactions to the saliva of the bedbug (up to 11 days later).
- Bedbug bites may be mistaken for bites from fleas or bites from mosquitoes or other arthropods. Bites from fleas tend to be on lower legs or ankles.
- Scabies. Scratching in patients with scabies is more often in the wrists, fingers and around the waistline.
- Other dermatological conditions which may be similar include:
Eradication of bedbugs
Control of infestation is difficult because of the ability of bedbugs to hide in furniture cracks and crevices, and their ability to survive long periods of time without feeding. The following non-chemical measures may be beneficial:
- Washing at 60°C or dry cleaning affected linen.
- Tumble drying affected linen on a hot cycle for at least half an hour.
- Freezing may also be effective; however, affected items must be kept frozen for at least one or two weeks.
- Disposal of highly infested items, together with physical removal of bedbugs and mattress covers and vacuuming, are usually recommended.
- Encasing mattresses in a protective covering (such as those used for people with allergies) may be an option; however, the seal needs to be tight, with no gaps in the encasement material.
Insecticides must be used only by professionals and it is recommended that expert guidance regarding eradication should always be sought.
Pyrethroids are the most commonly used insecticides for bedbug infestations.
Insect growth regulators and carbamates are also sometimes used. However, resistance to all types of insecticides has occurred. Therefore, a combination of insecticides is usually applied to all areas. Re-treatment may be indicated in some areas.
Carbon dioxide fumigation has been shown to be an effective alternative to conventional fumigants for eliminating bedbugs hiding in infested household items such as clothing, sofas, shoes and books.Fumigation for at least 24 hours is required.
Management of bedbug bites
- The symptoms of bedbug bites are often treated with topical steroids (such a hydrocortisone 1%) once or twice a day for up to seven days.
- Antihistamines may be beneficial for those with pruritus.
- Topical or systemic antibiotics may be necessary for those with secondary infection of their bites.
- People with an infestation should be encouraged to contact a pest control expert as soon as the pest has been identified.
Secondary infection from scratching can occur.
Although bedbugs have been suspected of transmitting infectious agents (eg, hepatitis B, hepatitis C, HIV or meticillin-resistant Staphylococcus aureus (MRSA)), no report has yet actually demonstrated that they are infectious disease vectors.
Sleep deprivation is common, with consequent social and health sequelae. In some individuals, psychological sequelae can result from bedbug biting events. These may include nightmares, flashbacks, hypervigilance (to keep the bugs away), insomnia and anxiety.
Further reading and references
Goddard J, deShazo R; Bed bugs (Cimex lectularius) and clinical consequences of their bites. JAMA. 2009 Apr 1301(13):1358-66. doi: 10.1001/jama.2009.405.
Delaunay P; Human travel and traveling bedbugs. J Travel Med. 2012 Dec19(6):373-9. doi: 10.1111/j.1708-8305.2012.00653.x. Epub 2012 Sep 24.
Adelman ZN, Miller DM, Myles KM; Bed bugs and infectious disease: a case for the arboviruses. PLoS Pathog. 2013 Aug9(8):e1003462. doi: 10.1371/journal.ppat.1003462. Epub 2013 Aug 15.
Bed bugs; British Pest Control Association (BPCA)
Bernardeschi C, Le Cleach L, Delaunay P, et al; Bed bug infestation. BMJ. 2013 Jan 22346:f138. doi: 10.1136/bmj.f138.
Potter K; Bed bugs, University of Kentucky Entomology Department, May 2012
Reinhardt K, Kempke D, Naylor RA, et al; Sensitivity to bites by the bedbug, Cimex lectularius. Med Vet Entomol. 2009 Jun23(2):163-6. doi: 10.1111/j.1365-2915.2008.00793.x. Epub 2009 Mar 9.
Naylor RA, Boase CJ; Practical solutions for treating laundry infested with Cimex lectularius (Hemiptera: Cimicidae). J Econ Entomol. 2010 Feb103(1):136-9.
Wang C, Lu L, Xu M; Carbon dioxide fumigation for controlling bed bugs. J Med Entomol. 2012 Sep49(5):1076-83.
Delaunay P, Blanc V, Del Giudice P, et al; Bedbugs and infectious diseases. Clin Infect Dis. 2011 Jan 1552(2):200-10. doi: 10.1093/cid/ciq102.
Doggett SL, Dwyer DE, Penas PF, et al; Bed bugs: clinical relevance and control options. Clin Microbiol Rev. 2012 Jan25(1):164-92. doi: 10.1128/â€‹CMR.05015-11.
Goddard J, de Shazo R; Psychological effects of bed bug attacks (Cimex lectularius L.). Am J Med. 2012 Jan125(1):101-3. doi: 10.1016/j.amjmed.2011.08.010.
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