Human Head Louse
Scientific Name: Pediculus humanus capitis
Order & Family: Order: Psocodea, Family: Pediculidae
Size: 2 to 3 mm in length (roughly the size of a sesame seed).
Natural Habitat
The scalp and hair of humans; they are obligate ectoparasites that cannot survive long away from a human host.
Diet & Feeding
They feed exclusively on human blood, typically several times a day.
Behavior Patterns
They are wingless and cannot jump or fly; they move by crawling. Eggs (nits) are cemented to the hair shaft near the scalp. They spread primarily through direct head-to-head contact.
Risks & Benefits
Risks include intense itching (pruritus) due to an allergic reaction to louse saliva, and potential secondary bacterial skin infections from scratching. They are not known to transmit systemic diseases. There are no known benefits to the host or ecosystem.
Identified on: 12/26/2025