Head Lice

The head louse (Pediculus humanus capitis) is a flat, wingless insect with three pair of legs, each ending in a claw. Head lice feed on human blood and live on human hair, where females lay 3-10 nits (eggs) a day and as many 60-100 nits in their 30 day lifetime. The nits are attached to a hair follicle with a fixative cement secreted by the louse, that make them difficult to remove. Adult head lice move very quickly from hair-to-hair on the infected person (2.5-12 inches per minute) and may be difficult to observe.

Pre-school and elementary children, ages 3-10, and their families are infested most often. The higher incidence of head lice among young children may be due to their increased physical contact with each other and the sharing of objects that had contact with human hair infested with head lice. There are more cases of head lice infestation among school-aged children then there are of all other communicable disease combined, except for the common cold.

SYMPTOMS OF HEAD LICE INFESTATION

The itching associated with head lice infestation is caused by an allergic reaction to the anticoagulant saliva of the head louse. Allergic reactions to the saliva are not immediate, and may take several weeks to appear. Therefore it is important to realize that a person who develops symptoms has probably been infested with head lice for several weeks.

Repeated scratching may lead to inflammation, and may create a mode of entry into the scalp for germs or lice feces resulting in secondary infections on the scalp. Persons with secondary infections may develop a mild fever and irritability.

SPREAD OF HEAD LICE

Direct transfer: Head-to-head contact may be responsible for most lice transfer.

Indirect transfer: Sharing objects (e.g., brushes, hats, head phones or head bands) that had contact with human hair infested with head lice within the previous 2 days, may allow transfer of live lice.

Facts on the spread of head lice:

• Head lice cannot jump or fly from head to head. Head lice can crawl very quickly from hair-to-hair and from the head of an infested person to the     head of a non-infested person if their heads are touching.
• Adult head lice and nymphs can be spread from person-to-person or from a contaminated object-to-person; nits cannot be spread person-to-person or from contaminated object-to-person.
• Pets do not spread head lice. Head lice feed on human blood only. Head lice do not spread disease.
• Head lice are not an indication of poor personal hygiene or living in an unclean environment.
• Shaving the head of an infested person is not recommended. Use discretion when cutting long hair or thick hair to assist in nit removal.