New research finds that head lice have developed a “high level” of resistance to some of the most common over-the-counter remedies – which means it could be a little more difficult to get rid of the itch-inducing pests.
Scientists sampled lice from 30 states in the United States for the study. Insects from 25 states, including California, Florida, Maine and Minnesota, showed mutations in genes that make them less susceptible to these insecticides such as pyrethroids.
"It's almost saturated with [these genes], which means that people using permethrin and pyrethrin based products will probably have a very hard time controlling the lice," said research leader Kyong Sup Yoon, associate professor of biological sciences and environmental sciences at Southern Illinois University.
However, this certainly doesn’t mean that lice cannot be killed at all. Apart from manual cleaning methods such as using a specially designed comb, Yoon said that the infestation can still be controlled by using other chemicals.
But even those can become useless with time.
“If you use a chemical over and over, these little creatures will eventually develop resistance. So we have to think before we use a treatment,” he added. “The good news is head lice don't carry disease. They're more a nuisance than anything else.”
Yoon will present his findings at the 250th National Meeting & Exposition of the American Chemical Society this week.