PARENTS battling infestations of lice on their children鈥檚 heads will soon
have a new weapon. A shampoo developed in the US causes lice eggs, or nits, to
glow under ultraviolet light, making them much easier to spot and remove by
hand.
Sydney Spiesel, a pediatrics professor at Yale University School of Medicine,
formulated the shampoo after he was forced to manually remove
pesticide-resistant lice and their eggs from a child鈥檚 head. 鈥淭he child had
thick, blonde hair. It took me an hour to go through this kid鈥檚 head,鈥� he
says.
Every year about 14 million children get head lice in the US alone. For
years, shampoos containing permethrin were used to keep the bugs at bay. But
recent studies鈥攁nd experience in schools and day nurseries鈥攕how that
lice have become resistant to this and other common pesticides.
Advertisement
Another ingredient in some head-lice shampoos is lindane, which is approved
by the Food and Drug Administration for treating lice. But lindane is a
carcinogen, and the US Consumers Union and other groups have warned that it
shouldn鈥檛 be used on children.
This leaves parents literally nit-picking, using special fine-toothed combs
bought at pharmacies. But the tiny eggs, at less than a millimetre across, are
hard to see鈥攁nd they stick tenaciously to the hair. If even a few eggs are
missed, the child can quickly become re-infested.
Knowing that lice eggs
contain chitin鈥攖he polysaccharide from which the exoskeletons of
arthropods are made鈥擲piesel took a commercial organic dye he knew would
bind to chitin and added it to an over-the-counter shampoo. The dye is
鈥渄elightfully cheap and delightfully non-toxic,鈥� he says.
The dye bound to the chitin in the eggs, but not to the hair or scalp. When
Spiesel shone a 鈥渂lack鈥� (UV) light on the eggs he saw a 鈥渂rilliant glow鈥� which
made them easy to remove. Spiesel claims he now holds a patent on his
lice-detecting shampoo, but he hasn鈥檛 licensed it. He says he鈥檚 looking for a
business partner to help him bring it to market.
A non-profit group that discourages the use of chemical treatments says
Spiesel鈥檚 idea is too complicated. 鈥淲e鈥檙e not really excited by this idea. The
best way is not to get people into dark rooms with black lights. We want to
enable people to screen them routinely,鈥� says Deborah Altschuler, president of
the National Pediculosis Association (www.headlice.org) in Newton,
Massachusetts.
The association recommends that parents routinely check their children for
signs of head lice and use a nit comb to remove eggs.