Bedbugs have been unwelcome bedfellows for humans for thousands of years. An increase in pyrethroid resistance, a ban on the insecticide dichloro-diphenyl-trichloroethane (DDT), increased international travel, and increased population density in large cities have led to an exponential rise in the incidence of bedbug infestations. Physicians are often at the forefront of bedbug infestation diagnosis.
Once the diagnosis is suggested, symptomatic treatment of the patient and extermination of the pests are essential, though time-consuming, costly, and often problematic. Measures to eliminate infestation and to prevent spread include identification of the pest, early detection, patient education, and professional eradication.
BEDBUGS: A BRIEF HISTORY
The term bedbug refers to the obligate parasitic arthropod Cimex lectularius (the common bedbug) and, less commonly, its tropical cousin C hemipterus. Bedbugs have coexisted with humans for centuries, dating back to the ancient Egyptians 3,500 years ago.1 Through the mid-20th century, about 30% of US households were infested with bedbugs.2 The introduction of pesticides during World War II markedly decreased the incidence, but with increased international travel, pesticide resistance, and the banning of certain pesticides in the last decade, bedbugs have reemerged worldwide.3
Bedbugs are red-brown, wingless, oval-shaped insects measuring 4 to 5 mm in length (Figure 1). They are hematophagous ectoparasites that preferentially feed on human blood, although they feed on some animals as well.2
Cimex lectularius dwells in temperate climates and C hemipterus in more tropical climates, but overlap and interbreeding are common. The usual life cycle is about 6 months, but some bugs live 12 months or longer. The female bedbug lays 5 to 8 eggs per week, or approximately 500 eggs in her lifetime, and each egg hatches in 5 to 10 days.4
These photophobic parasites do not live on their human hosts but rather simply visit for a meal. They cohabitate in dark locations, attacking human hosts when they are inactive or sleeping for long periods of time. Common living areas include mattress seams, box springs, bed linens and clothes, wallpaper seams, electrical outlets, and furniture seams (Table 1).5 The female bedbug lays her eggs in these secluded crevices, ensuring their safety until hatching. The dense nests of adult bedbugs, their eggs, and accumulated fecal matter allow for easy visual identification of infestation.5
Bedbugs typically feed between 1:00 am and 5:00 am. Though wingless, they successfully navigate towards their human host, attracted by emitted heat and carbon dioxide.2 Once attached to human skin, the bedbug bite releases enzymes and chemicals including nitrophorin and nitric oxide that facilitate bleeding; these substances are responsible for the resultant dermatitis. (Of note, bedbugs with experimentally excised salivary glands do not cause skin disease in humans.6) After feeding for 3 to 20 minutes, the length and weight of the arthropod can increase by 50% to 200%. A fully sated bedbug can survive for a year until its next meal.2,7 Even if an establishment, home, room, or article of clothing infested with bedbugs has been abandoned for several months, without proper eradication the item still represents a possible nidus for recurrent disease if used, inhabited, or worn again.
From the earliest documented cases of Cimex in ancient Egyptian tombs to the mid-1900s, the cohabitation of humans and bedbugs was seen as inevitable. With the introduction of DDT 60 years ago, the bedbug population significantly decreased.8 Since DDT’s prohibition, coupled with increased travel and heightened resistance to over-the-counter insecticides, the bedbug population has reemerged exponentially.9,10
Infestations have been reported worldwide, on every continent, and in all 50 of the United States. In Australia, infestations have risen 4,500% in the last 10 to 15 years.11 In the United States, infestation occurs exclusively with C lectularius and the incidence is rising. Philadelphia and New York City are among the most bedbug-infested US cities. New York City experienced a 2,000% increase in bedbug complaints between 2004 and 2009.8
Bedbugs can be transmitted either through active migration of colonies from one area to another adjacent living area through wall spaces or ventilation, or through passive transportation in luggage, clothing, furniture, used mattresses, bookbags, and other personal items.1 Although infestation affects people of all socioeconomic classes and backgrounds, the likelihood increases in people who frequently travel and people who live in lower income neighborhoods with tightly packed apartments. Bedbug infestations are also common in refugee camps: 98% of the rooms in a refugee camp in Sierra Leone had bedbugs, and almost 90% of the residents had signs of bites.12 Unlike scabies, direct person-to-person, skin-to-skin transfer is rare.