Human Head Louse

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea; Family: Pediculidae

Size: 2-3 mm (approximate size of a sesame seed)

Human Head Louse

Natural Habitat

Exclusively the human scalp and hair

Diet & Feeding

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

Behavior Patterns

They are wingless and cannot jump; they move by crawling. They lay eggs (nits) which are glued to the hair shaft near the scalp. They cannot survive for more than 24-48 hours off a human host.

Risks & Benefits

They do not transmit disease but cause intense itching (pruritus) and potential secondary skin infections from scratching. They are considered a nuisance rather than a medical biological threat.

Identified on: 3/11/2026