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PUBLIC HEALTH
Epidemiology: Even though head-lice infestation is common, affecting about 10% of primary grade school children and their families each year, few people talk about it.1 The condition has been stigmatized by the false belief that lice are attracted to dirty scalps and unkempt hair. In fact, the lowly louse with the lofty name - Pediculus humanus capitus - does not discriminate on the basis of hygiene. The only essentials for this wingless parasite are hair to cling to and scalp blood to feed on.
The adult louse is the size of a sesame seed, has 6 legs and assumes the shade of the hair it infests. The female lays yellow, shiny, oval eggs (nits) that cement firmly to the hair shaft near the scalp. Within a week the nits hatch into nymphs, which mature into adults about 7 days after hatching. Adults can live up to 30 days on a person's head.2
Transmission typically occurs between people who know each other well, and outbreaks are common when children return to school after summer holidays; it takes about 30 seconds for lice to move from one infested head to another, which means that prolonged head-to-head contact is usually required before they spread.3 Children aged 3 to 10 years and their families are infested most often, girls more so than boys. Infestations can also be started by wearing infested clothing,...