What are lice and where do they live? - briefly
Lice are minute, wingless ectoparasites that feed on blood or skin debris. They inhabit the hair, fur, or feathers of mammals and birds, with certain species adapting to live in human clothing.
What are lice and where do they live? - in detail
Lice are obligate ectoparasites belonging to the order Phthiraptera. They are wingless insects with flattened bodies, chewing mouthparts, and specialized claws that enable attachment to hair or feathers. Their life cycle comprises egg (nit), nymph, and adult stages; development occurs entirely on the host, with eggs hatching in 5–10 days and maturity reached within 2–3 weeks.
Four primary species infest humans:
- Pediculus humanus capitis – head lice, residing on scalp hair and feeding several times daily.
- Pediculus humanus corporis – body lice, living in the seams of clothing and moving to the skin to feed.
- Pthirus pubis – pubic lice, inhabiting coarse hair of the genital region, perianal area, and occasionally chest or facial hair.
- Pediculus humanus (general term for both head and body forms) – sometimes used interchangeably in literature.
Habitat characteristics:
- Scalp and hair – provides a warm, moist environment with frequent blood meals.
- Clothing seams – offers protection from removal, with access to skin for feeding.
- Coarse body hair – supplies grip for larger claws and a stable microclimate.
Geographic distribution is worldwide; infestations occur wherever human populations exist, with prevalence higher in crowded or unhygienic conditions. Environmental factors such as temperature (optimal 30–32 °C) and humidity (50–70 %) support egg viability and nymph development.
Transmission occurs through direct contact with an infested individual or, for body lice, via contaminated clothing and bedding. Lice cannot survive more than 48 hours off a host, limiting indirect spread.
Control measures focus on mechanical removal of eggs, topical insecticides, and laundering of clothing at temperatures above 60 °C to eliminate body‑lice populations. Regular inspection of hair and body hair reduces the risk of sustained infestation.