Lice

Although lice are often mistakenly thought to be a symbol of inadequate hygiene or poverty, head lice can infest the most fastidious child or adult. In fact, lice actually prefer clean hair because it makes it easier for them to move around and attach their eggs.

Children are the most common targets for these blood-sucking parasites because of their tendency to play closely together and share clothing, which provides the lice with opportunities to move easily from one victim to another. As one of the leading causes of school absences, lice are a growing problem in the U.S., infesting an estimated 6 to 12 million people each year.

An infestation of head lice sends most people running to the drugstore or doctor’s office for a lice-killing shampoo. But the majority of these preparations contain pesticides such as pyrethrins (also found in flea shampoos and roach sprays) or lindane, a dangerous chemical linked to cancer and nervous system damage. In addition, recent reports raise the suspicion that lice are becoming resistant to the pesticides used against them.