Head Lice Head lice are parasitic insects that live on the head. They survive by feeding on human blood. Lice infestations are spread most commonly by close person-to-person contact. Lice move by crawling; they cannot hop or fly. Adult head lice are 2–3 mm in length. Head lice infest the head and neck and attach their eggs to the base of the hair shaft. Lice move by crawling; they cannot hop or fly.
Figure 9.9 – Adult head louse.20
Symptoms of a head lice infestation include:
Tickling feeling of something moving in the hair.
Itching, caused by an allergic reaction to the bites of the head louse.
Irritability and difficulty sleeping; head lice are most active in the dark.
Sores on the head caused by scratching. These sores can sometimes become infected with bacteria found on the person’s skin.