Body Louse / Head Louse (Nymph/Adult)

Scientific Name: Pediculus humanus

Order & Family: Order: Psocodea (formerly Phthiraptera); Family: Pediculidae

Size: 1 mm to 3 mm (approx. the size of a sesame seed).

Natural Habitat

Exclusively found on the human body, specifically on the head/scalp (Head louse) or in clothing/bedding (Body louse).

Diet & Feeding

Obligate hematophages; they feed exclusively on human blood several times a day.

Behavior Patterns

They are wingless and cannot jump or fly; they move by crawling. They glue their eggs (nits) to hair shafts or clothing fibers. They require close proximity to a human host for warmth and food, usually dying within 24-48 hours if separated from a host.

Risks & Benefits

Risks: Cause intense itching (pruritus) due to an allergic reaction to saliva. Body lice (but not head lice) can transmit serious diseases like epidemic typhus, trench fever, and louse-borne relapsing fever. Benefits: None.

Identified on: 1/8/2026