Head Lice Becoming Resistant To Treatment
Researchers: Best Defense Is Good Hygiene
UPDATED: 11:39 a.m. EDT October 25, 2002
Health departments have reported that head lice are becoming resistant to existing treatments.
The departments have noted a growing number of complaints from schools saying the recommended shampoo treatments are not working.
The most common ingredient in various products used to treat head lice is permethrin, which is derived from natural compounds in chrysanthemum flowers, according to John Clark, a professor at the University of Massachusetts at Amherst.
Researchers at the university are growing lice in colonies to study their resistance to permethrin. They hope their work will lead to new ways to control head lice.
The group found that resisance to permethrin ranged from 50 percent in some Los Angeles school children to about 98 percent in a migrant workers' camp in Florida. Clark's research group also did sampling in Texas, where resistance was found to be 75 to 80 percent.
Clark said overuse of products containing permethrin is likely the main reason for the resistance problem.
"I believe, and a lot of other people that study resistance believe, that it's the misuse of these over-the-counter products that have been the real problem in terms of selecting resistance," Clark said.
While researchers investigate head lice resistance, they recommend a program of good personal hygiene as the best defense. Do not share combs, brushes, or headgear, officials say.
The lice are difficult to see, but their eggs, called "nits," are more easily recognizable.
The departments have noted a growing number of complaints from schools saying the recommended shampoo treatments are not working.
The most common ingredient in various products used to treat head lice is permethrin, which is derived from natural compounds in chrysanthemum flowers, according to John Clark, a professor at the University of Massachusetts at Amherst.
Researchers at the university are growing lice in colonies to study their resistance to permethrin. They hope their work will lead to new ways to control head lice.
The group found that resisance to permethrin ranged from 50 percent in some Los Angeles school children to about 98 percent in a migrant workers' camp in Florida. Clark's research group also did sampling in Texas, where resistance was found to be 75 to 80 percent.
Clark said overuse of products containing permethrin is likely the main reason for the resistance problem.
"I believe, and a lot of other people that study resistance believe, that it's the misuse of these over-the-counter products that have been the real problem in terms of selecting resistance," Clark said.
While researchers investigate head lice resistance, they recommend a program of good personal hygiene as the best defense. Do not share combs, brushes, or headgear, officials say.
The lice are difficult to see, but their eggs, called "nits," are more easily recognizable.
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