What is a body louse? - briefly
The body louse (Pediculus humanus corporis) is a wingless, blood‑feeding ectoparasite that inhabits the seams of clothing and crawls onto the skin to feed. It serves as a vector for bacterial diseases including epidemic typhus, relapsing fever, and trench fever.
What is a body louse? - in detail
The body louse, scientifically named Pediculus humanus corporis, is a wing‑less, blood‑feeding ectoparasite that inhabits the seams of clothing rather than the skin itself. It belongs to the order Phthiraptera, family Pediculidae, and is closely related to the head louse (P. humanus capitis).
Adult specimens measure 2–4 mm in length, are gray‑brown, and possess a flattened body adapted for moving through fabric fibers. Six legs end in clawed tarsi that grip cloth fibers. The head bears short antennae and compound eyes, while the thorax supports the legs and mouthparts specialized for piercing the host’s epidermis.
The life cycle comprises three stages: egg (nit), nymph, and adult. Females lay 4–5 eggs per day, attaching them to clothing fibers. Eggs hatch in 6–9 days, releasing nymphs that undergo three molts over 9–12 days before reaching maturity. Adults live 30–40 days on a human host, requiring a blood meal every 4–5 hours.
Habitat preference includes warm, humid environments where clothing remains in prolonged contact with the body. Lice migrate to the skin only to feed, then return to the garment. Off‑host survival ranges from 5 days in cool, dry conditions to up to 2 weeks in moist, warm settings.
Key pathogens transmitted by this parasite are:
- Rickettsia prowazekii – causative agent of epidemic typhus
- Bartonella quintana – responsible for trench fever
- Borrelia recurrentis – agent of relapsing fever
Transmission occurs when lice defecate on the skin during feeding; pathogen‑laden feces enter the bloodstream through scratching or abrasions.
Clinical manifestations include intense pruritus, a maculopapular rash, and visible lice or nits on clothing seams. Secondary bacterial infection may develop at sites of excoriation.
Diagnosis relies on direct visual identification of live insects or attached nits in clothing, supplemented by microscopic examination of collected specimens.
Control strategies focus on eliminating the insect’s habitat:
- Wash clothing at ≥60 °C, followed by tumble drying on high heat
- Iron garments to destroy eggs and nymphs
- Use insecticide‑treated clothing or apply topical permethrin to infested items
- Maintain personal hygiene and avoid prolonged wearing of unwashed garments
Outbreaks commonly arise in overcrowded, unsanitary settings such as refugee camps, prisons, or disaster shelters, where limited access to clean clothing facilitates rapid spread. Effective public‑health response combines environmental decontamination with education on personal hygiene and prompt treatment of affected individuals.