(WVUE) - Lice in at least 25 states show resistance to common treatments, according to research presented by the American Chemical society.
Scientists report that lice populations in at least 25 states have developed resistance to over-the-counter treatments still widely recommended by doctors and schools.
In a recent study, a study scientists tout as one of the largest of its kind, lice were gathered from 30 states with the help of public health workers. The lice were tested and found with "knock-down resistance" mutations, which affect the insects' nervous system and desensitize them to insecticides in many over-the-counter treatments, according to the American Chemical Society.
The only state with a population of lice still largely susceptible to the insecticide was Michigan. Why lice haven't developed resistance there is still under investigation, researchers say.
"If you use a chemical over and over, these little creatures will eventually develop resistance," said Kyong Yoon, Ph.D., with Southern Illinois University. "So we have to think before we use a treatment. The good news is head lice don't carry disease. They're more a nuisance than anything else."
So what are parents to do? Researchers say that lice can still be controlled by using different chemicals, some of which are available only by prescription.