‘Super’ head lice: Resistant Lice
Published: August 19, 2015
‘Super’ head lice: Resistant Lice, Head lice are becoming immune to common treatments, scientists have revealed, meaning parents are fighting a losing battle with nits in their children’s hair.
With the return to school on the horizon, parents will be worried to learn that new research suggests that head lice have developed a “high level” of resistance to some of the most popular treatments.
The itch-inducing pests lead to missed school days and frustrated parents, who could have even more reason to be wary of the bug this year.
Scientists report that lice in at least 25 American states have developed resistance to over-the-counter treatments still widely recommended by doctors and schools.
Doctor Kyong Yoon, of Southern Illinois University, said: “We are the first group to collect lice samples from a large number of populations across the United States.
“What we found was that 104 out of the 109 lice populations we tested had high levels of gene mutations, which have been linked to resistance to pyrethroids.”
Pyrethroids are a family of insecticides used widely indoors and outdoors to control mosquitoes and other insects. It includes permethrin, the active ingredient in some of the most common lice treatments sold over the counter.
Dr Yoon said that the momentum toward widespread pyrethroid-resistant lice has been building for years. The first report on the development came from Israel in the late 1990s.
He became one of the first to report the phenomenon in the US in 2000 when he was a graduate student at the University of Massachusetts.
Dr Yoon said: “I was working on insecticide metabolism in a potato beetle when my mentor, John Clark, suggested I look into the resurgence of head lice.
“I asked him in what country and was surprised when he said the US.”
Dr Yoon tested the pests for a trio of genetic mutations known collectively as kdr, which stands for “knock-down resistance” which were first found in house flies in the late 1970s after farmers began using pyrethroids rather than DDT.
He found many of the lice did indeed have kdr mutations, which affect an insect’s nervous system and desensitise them to pyrethroids. Since then, he has expanded his survey.
In the most recent study he gathered lice from 30 states and discovered that samples from 25, including California, Texas, Florida and Maine, had all three genetic mutations associated with kdr making them the most resistant to pyrethroids.
Samples from four states – New York, New Jersey, New Mexico and Oregon – had one, two or three mutations. The only state with a population of lice still largely susceptible to the insecticide was Michigan. Dr Yoon said why lice haven’t developed resistance there is still under investigation.
Dr Yoon says that lice can still be controlled by using different chemicals, some of which are available only by prescription.
But he added: “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. The good news is head lice don’t carry disease. They’re more a nuisance than anything else.”
The findings are due to be presented at the 250th National Meeting and Exposition of the American Chemical Society.
News of head lice being increasingly immune to over the counter treatments has certainly got Telegraph readers talking. Here is a selection of your favourite home remedies.
Did all my children with lots of conditioner, rubbed it in, combed it out, the whole head, up to the scalp with a nit comb taking the lice and nits with it. Repeat for four days in succession. Effective, no hassle, no chemicals, nice hair,” writes Liberty.
Super easy to kill them, and without nasty chemicals: tea tree oil shampoo,” writes radiostar.
I just use a nit comb after putting shampoo or conditioner in the kids’ hair, repeating a few days later to give any nits I miss time to hatch and get caught. A thorough comb through only takes 10 minutes and is surprisingly therapeutic,” writes Dale.
Use conditioner, comb though every evening for two weeks in the bath, break the cycle, bond with your children who will love having their hair combed. It’s not difficult,” writes Fred.
Liquid paraffin, olive oil or coconut oil work too” writes Blue Screen of Death.
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