Human Head Louse

Exclusively found on the human scalp and hair, where they remain close to the skin for warmth and food.

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

They are wingless and cannot jump or fly; they move by crawling. They cement their eggs (nits) to hair shafts. They cannot survive for more than about 24 to 48 hours off a human host.

They cause intense itching (pediculosis) and scalp irritation due to an allergic reaction to their saliva. While they are a nuisance and can lead to secondary skin infections from scratching, they are not known to transmit systemic bacterial or viral diseases.