Where do lice live in a human? - briefly
Lice reside on the scalp and other hair‑covered areas of the body, securing their eggs (nits) to individual strands near the skin. They feed on blood drawn from the surface of the skin and stay confined to these hair‑bearing regions.
Where do lice live in a human? - in detail
Lice are obligate ectoparasites that occupy specific micro‑habitats on the human body where temperature, humidity, and access to blood are optimal.
The most common species, Pediculus humanus capitis (head louse), resides in the scalp hair. Adult insects cling to the shaft of each hair strand, positioning their bodies close to the scalp to feed on capillary blood. Eggs (nits) are cemented to the hair at a distance of 1–2 mm from the scalp, a location that ensures the developing embryo remains within the warm, moist environment required for hatching.
Pediculus humanus corporis (body louse) prefers densely haired regions such as the armpits, groin, and the lower abdomen. Unlike the head louse, it spends most of its time on clothing fibers, especially the seams of shirts, underwear, and socks, where it can move to the skin surface to take blood meals. The insect’s claws are adapted to grasp fabric, allowing it to survive in the dry inter‑stices of garments while still accessing the host’s skin.
Pthirus pubis (pubic louse) inhabits coarse hair of the genital area, perianal region, and occasionally the chest, abdomen, or facial hair. Its larger claw structure enables a secure grip on thicker hairs, and the parasite remains close to the skin surface to feed.
Additional, less common sites include:
- Eyebrows and eyelashes, where head lice may lay nits and occasionally feed.
- Facial hair (beard, moustache) in men, providing a suitable niche for both head and body lice.
- Skin folds such as the neck, behind the ears, and the waistband area, which retain moisture and protect nits from removal.
The selection of these locations reflects the parasite’s need for:
- Consistent warmth (approximately 30–34 °C).
- High relative humidity (≥50 %) to prevent desiccation.
- Easy access to superficial capillaries for blood ingestion.
- Secure attachment points for eggs and adults.
Understanding the precise habitats of each lice species informs effective treatment, targeting the specific body region and associated clothing or hair structures where the insects reside.