The National Pediculosis Association, a non-profit group behind the website HeadLice.org, also offers suggestions for frantic parents who find that a lice treatment product hasn’t worked. (Home lice remedies can be deadly.).
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That very fact has made the increase in prevalence of lice cases since the 1990s – despite the corresponding increased access to effective treatments – so puzzling.
In time for the start of school for many kids, lice in 25 states have developed resistance to common over-the-counter treatments. Pyrethroids include permethrin, which is used in some of the most common drug-store treatments of lice, the release noted. Samples from New Mexico, New Jersey, New York, and Oregon had one, two, or three mutations; the only state without any mutations was Michigan, although researchers are not sure why. The situation has been developing for many years, says researcher Kyong Yoon, Ph.D., of Southern Illinois University.
The trio of mutations – called kdr, for “knock down resistance” – affects the insect’s nervous system and makes them less sensitive to the insecticide chemicals that are found in lice treatments and also in mosquito repellant or fly spray, for example. The new study found lice with all three genetic mutations in the 25 states pictured above in dark blue.
In the most recent study, he cast the widest net yet, gathering lice from 30 states with the help of a broad network of public health workers.
[Untangling the myths about head lice]. (“My PhD entirely focused on head lice”, he says with a laugh.) Using the services of professional nitpickers across the country, Yoon decided to take an American lice census by collecting pest populations from every state.
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Yoon said that lice can still be controlled by using different chemicals, but even those might only work for so long. “If you use a chemical over and over, these little creatures will eventually develop some resistance”, he said. “So we have to think before we use a treatment”. Though head lice aren’t known to transmit any diseases, they can be an itchy nuisance-and now, they’re harder to kill.
