Cimex lectularius and Cimex hemipterus
- Parasite
- For completeness
Flat, reddish-brown insects that hide in beds and bite at night. Bites itch and disturb sleep, but bed bugs are not known to spread disease.
Also called: bed bugs, chinches de cama
Quick facts
- Type
- Parasite · Ectoparasites
- Gram / shape
- Oval
- Spread
- Carried in luggage · They come out at night
- Causes
- Cimicosis · Papular urticaria and
- Treatment
- Bites
At a glance
- Shape
- Oval, flat, reddish-brown body that swells and darkens after feeding
- Family
- Cimicidae
- Type
- Wingless blood-feeding insects (Hemiptera), temporary ectoparasites
- Size
- About 1–7 mm depending on stage
Morphology
- Flat body that fits into mattress seams, bed frames, cracks and behind sockets.
- Beak-like piercing mouthparts folded under the head.
- Nymphs are paler, almost translucent, and turn red after a meal.
Transmission
- Carried in luggage, clothing, used furniture and mattresses between homes, hotels, hostels and shelters.
- They come out at night, feed for a few minutes on sleeping people, then hide again.
- Infestation has nothing to do with dirt: it follows travel and moving belongings.
Reservoir: Human dwellings, hotels, shelters, dormitories and public transport; Bats and birds for related species
Isolation precautions
What the care team adds to standard precautions.
- Standard
Life cycle
- The female lays a few eggs a day in cracks and seams, glued to surfaces.
- Eggs hatch in about one to two weeks into nymphs that look like small adults.
- Each of the five nymph stages needs a blood meal before moulting.
- Adults feed every few days and can live many months.
- Adults and nymphs survive several months without feeding, so empty rooms stay infested.
Virulence factors
- Saliva with anaesthetic and anticoagulant substances: the bite is not felt.
- Reactions are hypersensitivity: many people have none, others itchy wheals.
- Infestations cause insomnia, anxiety and social stigma.
- Widespread resistance to common insecticides.
Diseases it causes
- Cimicosis: itchy bite reactions, often in rows or clusters
- Papular urticaria and, rarely, severe allergic reactions including anaphylaxis
- Secondary bacterial infection from scratching
Clinical picture
- Itchy red papules or wheals on exposed skin (face, neck, arms), often in a line or cluster.
- Reactions may appear one to several days after the bite.
- Several people sleeping in the same place are affected; insomnia and anxiety are common.
Diagnosis
- Clinical picture plus finding the insect: live bugs, shed skins and eggs in mattress seams and furniture.
- Rusty or dark spots of blood and faeces on sheets and mattresses; a sweet, musty odour in heavy infestations.
- Bites alone cannot confirm bed bugs: mosquito and flea bites look alike.
Treatment
Bites: avoid scratching, antiseptic care, topical corticosteroids and oral antihistamines for itch; emergency care for anaphylaxis. Infestations need professional integrated pest management, not repeated self-spraying.
Drug class only; doses and regimens are set by the clinician from the current guideline.
In Pharmacology:
Prevention
- Inspect beds and luggage when travelling; keep bags off the floor and bed.
- Wash and dry clothing at high temperature after trips or when infested.
- Inspect second-hand furniture and mattresses before bringing them home.
- Mattress encasements, reducing clutter and vacuuming seams and cracks.
- Early detection: small infestations are much easier to control.
Test yourself
Think of the answer, then tap the question to see it.
Do bed bugs transmit infections to people?
They are not known to spread disease; the problems are itching, allergic reactions, superinfection and sleep loss.
Where do bed bugs hide during the day?
In mattress seams, bed frames, headboards, furniture cracks and behind wall fittings near where people sleep.
Why can an empty apartment stay infested?
Because adults and nymphs can survive several months without a blood meal.
What signs on the bed suggest an infestation?
Rusty blood or faecal spots, shed skins, eggs and live bugs in seams, and a musty odour.
Connections
← Back to the group: Ectoparasites
Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: About Bed Bugs | Bed Bugs | CDC (CDC, 2024); Bed Bugs: Get Them Out and Keep Them Out (US EPA, 2025).
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Representative model, for educational purposes only.